--- /dev/null
+ ============================
+ KERNEL KEY RETENTION SERVICE
+ ============================
+
+This service allows cryptographic keys, authentication tokens, cross-domain
+user mappings, and similar to be cached in the kernel for the use of
+filesystems other kernel services.
+
+Keyrings are permitted; these are a special type of key that can hold links to
+other keys. Processes each have three standard keyring subscriptions that a
+kernel service can search for relevant keys.
+
+The key service can be configured on by enabling:
+
+ "Security options"/"Enable access key retention support" (CONFIG_KEYS)
+
+This document has the following sections:
+
+ - Key overview
+ - Key service overview
+ - Key access permissions
+ - New procfs files
+ - Userspace system call interface
+ - Kernel services
+ - Defining a key type
+ - Request-key callback service
+ - Key access filesystem
+
+
+============
+KEY OVERVIEW
+============
+
+In this context, keys represent units of cryptographic data, authentication
+tokens, keyrings, etc.. These are represented in the kernel by struct key.
+
+Each key has a number of attributes:
+
+ - A serial number.
+ - A type.
+ - A description (for matching a key in a search).
+ - Access control information.
+ - An expiry time.
+ - A payload.
+ - State.
+
+
+ (*) Each key is issued a serial number of type key_serial_t that is unique
+ for the lifetime of that key. All serial numbers are positive non-zero
+ 32-bit integers.
+
+ Userspace programs can use a key's serial numbers as a way to gain access
+ to it, subject to permission checking.
+
+ (*) Each key is of a defined "type". Types must be registered inside the
+ kernel by a kernel service (such as a filesystem) before keys of that
+ type can be added or used. Userspace programs cannot define new types
+ directly.
+
+ Key types are represented in the kernel by struct key_type. This defines
+ a number of operations that can be performed on a key of that type.
+
+ Should a type be removed from the system, all the keys of that type will
+ be invalidated.
+
+ (*) Each key has a description. This should be a printable string. The key
+ type provides an operation to perform a match between the description on
+ a key and a criterion string.
+
+ (*) Each key has an owner user ID, a group ID and a permissions mask. These
+ are used to control what a process may do to a key from userspace, and
+ whether a kernel service will be able to find the key.
+
+ (*) Each key can be set to expire at a specific time by the key type's
+ instantiation function. Keys can also be immortal.
+
+ (*) Each key can have a payload. This is a quantity of data that represent
+ the actual "key". In the case of a keyring, this is a list of keys to
+ which the keyring links; in the case of a user-defined key, it's an
+ arbitrary blob of data.
+
+ Having a payload is not required; and the payload can, in fact, just be a
+ value stored in the struct key itself.
+
+ When a key is instantiated, the key type's instantiation function is
+ called with a blob of data, and that then creates the key's payload in
+ some way.
+
+ Similarly, when userspace wants to read back the contents of the key, if
+ permitted, another key type operation will be called to convert the key's
+ attached payload back into a blob of data.
+
+ (*) Each key can be in one of a number of basic states:
+
+ (*) Uninstantiated. The key exists, but does not have any data
+ attached. Keys being requested from userspace will be in this state.
+
+ (*) Instantiated. This is the normal state. The key is fully formed, and
+ has data attached.
+
+ (*) Negative. This is a relatively short-lived state. The key acts as a
+ note saying that a previous call out to userspace failed, and acts as
+ a throttle on key lookups. A negative key can be updated to a normal
+ state.
+
+ (*) Expired. Keys can have lifetimes set. If their lifetime is exceeded,
+ they traverse to this state. An expired key can be updated back to a
+ normal state.
+
+ (*) Revoked. A key is put in this state by userspace action. It can't be
+ found or operated upon (apart from by unlinking it).
+
+ (*) Dead. The key's type was unregistered, and so the key is now useless.
+
+
+====================
+KEY SERVICE OVERVIEW
+====================
+
+The key service provides a number of features besides keys:
+
+ (*) The key service defines two special key types:
+
+ (+) "keyring"
+
+ Keyrings are special keys that contain a list of other keys. Keyring
+ lists can be modified using various system calls. Keyrings should not
+ be given a payload when created.
+
+ (+) "user"
+
+ A key of this type has a description and a payload that are arbitrary
+ blobs of data. These can be created, updated and read by userspace,
+ and aren't intended for use by kernel services.
+
+ (*) Each process subscribes to three keyrings: a thread-specific keyring, a
+ process-specific keyring, and a session-specific keyring.
+
+ The thread-specific keyring is discarded from the child when any sort of
+ clone, fork, vfork or execve occurs. A new keyring is created only when
+ required.
+
+ The process-specific keyring is replaced with an empty one in the child
+ on clone, fork, vfork unless CLONE_THREAD is supplied, in which case it
+ is shared. execve also discards the process's process keyring and creates
+ a new one.
+
+ The session-specific keyring is persistent across clone, fork, vfork and
+ execve, even when the latter executes a set-UID or set-GID binary. A
+ process can, however, replace its current session keyring with a new one
+ by using PR_JOIN_SESSION_KEYRING. It is permitted to request an anonymous
+ new one, or to attempt to create or join one of a specific name.
+
+ The ownership of the thread and process-specific keyrings changes when
+ the real UID and GID of the thread changes.
+
+ (*) Each user ID resident in the system holds two special keyrings: a user
+ specific keyring and a default user session keyring. The default session
+ keyring is initialised with a link to the user-specific keyring.
+
+ When a process changes its real UID, if it used to have no session key, it
+ will be subscribed to the default session key for the new UID.
+
+ If a process attempts to access its session key when it doesn't have one,
+ it will be subscribed to the default for its current UID.
+
+ (*) Each user has two quotas against which the keys they own are tracked. One
+ limits the total number of keys and keyrings, the other limits the total
+ amount of description and payload space that can be consumed.
+
+ The user can view information on this and other statistics through procfs
+ files.
+
+ Process-specific and thread-specific keyrings are not counted towards a
+ user's quota.
+
+ If a system call that modifies a key or keyring in some way would put the
+ user over quota, the operation is refused and error EDQUOT is returned.
+
+ (*) There's a system call interface by which userspace programs can create
+ and manipulate keys and keyrings.
+
+ (*) There's a kernel interface by which services can register types and
+ search for keys.
+
+ (*) There's a way for the a search done from the kernel to call back to
+ userspace to request a key that can't be found in a process's keyrings.
+
+ (*) An optional filesystem is available through which the key database can be
+ viewed and manipulated.
+
+
+======================
+KEY ACCESS PERMISSIONS
+======================
+
+Keys have an owner user ID, a group access ID, and a permissions mask. The
+mask has up to eight bits each for user, group and other access. Only five of
+each set of eight bits are defined. These permissions granted are:
+
+ (*) View
+
+ This permits a key or keyring's attributes to be viewed - including key
+ type and description.
+
+ (*) Read
+
+ This permits a key's payload to be viewed or a keyring's list of linked
+ keys.
+
+ (*) Write
+
+ This permits a key's payload to be instantiated or updated, or it allows
+ a link to be added to or removed from a keyring.
+
+ (*) Search
+
+ This permits keyrings to be searched and keys to be found. Searches can
+ only recurse into nested keyrings that have search permission set.
+
+ (*) Link
+
+ This permits a key or keyring to be linked to. To create a link from a
+ keyring to a key, a process must have Write permission on the keyring and
+ Link permission on the key.
+
+For changing the ownership, group ID or permissions mask, being the owner of
+the key or having the sysadmin capability is sufficient.
+
+
+================
+NEW PROCFS FILES
+================
+
+Two files have been added to procfs by which an administrator can find out
+about the status of the key service:
+
+ (*) /proc/keys
+
+ This lists all the keys on the system, giving information about their
+ type, description and permissions. The payload of the key is not
+ available this way:
+
+ SERIAL FLAGS USAGE EXPY PERM UID GID TYPE DESCRIPTION: SUMMARY
+ 00000001 I----- 39 perm 1f0000 0 0 keyring _uid_ses.0: 1/4
+ 00000002 I----- 2 perm 1f0000 0 0 keyring _uid.0: empty
+ 00000007 I----- 1 perm 1f0000 0 0 keyring _pid.1: empty
+ 0000018d I----- 1 perm 1f0000 0 0 keyring _pid.412: empty
+ 000004d2 I--Q-- 1 perm 1f0000 32 -1 keyring _uid.32: 1/4
+ 000004d3 I--Q-- 3 perm 1f0000 32 -1 keyring _uid_ses.32: empty
+ 00000892 I--QU- 1 perm 1f0000 0 0 user metal:copper: 0
+ 00000893 I--Q-N 1 35s 1f0000 0 0 user metal:silver: 0
+ 00000894 I--Q-- 1 10h 1f0000 0 0 user metal:gold: 0
+
+ The flags are:
+
+ I Instantiated
+ R Revoked
+ D Dead
+ Q Contributes to user's quota
+ U Under contruction by callback to userspace
+ N Negative key
+
+ This file must be enabled at kernel configuration time as it allows anyone
+ to list the keys database.
+
+ (*) /proc/key-users
+
+ This file lists the tracking data for each user that has at least one key
+ on the system. Such data includes quota information and statistics:
+
+ [root@andromeda root]# cat /proc/key-users
+ 0: 46 45/45 1/100 13/10000
+ 29: 2 2/2 2/100 40/10000
+ 32: 2 2/2 2/100 40/10000
+ 38: 2 2/2 2/100 40/10000
+
+ The format of each line is
+ <UID>: User ID to which this applies
+ <usage> Structure refcount
+ <inst>/<keys> Total number of keys and number instantiated
+ <keys>/<max> Key count quota
+ <bytes>/<max> Key size quota
+
+
+===============================
+USERSPACE SYSTEM CALL INTERFACE
+===============================
+
+Userspace can manipulate keys directly through three new syscalls: add_key,
+request_key and keyctl. The latter provides a number of functions for
+manipulating keys.
+
+When referring to a key directly, userspace programs should use the key's
+serial number (a positive 32-bit integer). However, there are some special
+values available for referring to special keys and keyrings that relate to the
+process making the call:
+
+ CONSTANT VALUE KEY REFERENCED
+ ============================== ====== ===========================
+ KEY_SPEC_THREAD_KEYRING -1 thread-specific keyring
+ KEY_SPEC_PROCESS_KEYRING -2 process-specific keyring
+ KEY_SPEC_SESSION_KEYRING -3 session-specific keyring
+ KEY_SPEC_USER_KEYRING -4 UID-specific keyring
+ KEY_SPEC_USER_SESSION_KEYRING -5 UID-session keyring
+ KEY_SPEC_GROUP_KEYRING -6 GID-specific keyring
+
+
+The main syscalls are:
+
+ (*) Create a new key of given type, description and payload and add it to the
+ nominated keyring:
+
+ key_serial_t add_key(const char *type, const char *desc,
+ const void *payload, size_t plen,
+ key_serial_t keyring);
+
+ If a key of the same type and description as that proposed already exists
+ in the keyring, this will try to update it with the given payload, or it
+ will return error EEXIST if that function is not supported by the key
+ type. The process must also have permission to write to the key to be
+ able to update it. The new key will have all user permissions granted and
+ no group or third party permissions.
+
+ Otherwise, this will attempt to create a new key of the specified type
+ and description, and to instantiate it with the supplied payload and
+ attach it to the keyring. In this case, an error will be generated if the
+ process does not have permission to write to the keyring.
+
+ The payload is optional, and the pointer can be NULL if not required by
+ the type. The payload is plen in size, and plen can be zero for an empty
+ payload.
+
+ A new keyring can be generated by setting type "keyring", the keyring
+ name as the description (or NULL) and setting the payload to NULL.
+
+ User defined keys can be created by specifying type "user". It is
+ recommended that a user defined key's description by prefixed with a type
+ ID and a colon, such as "krb5tgt:" for a Kerberos 5 ticket granting
+ ticket.
+
+ Any other type must have been registered with the kernel in advance by a
+ kernel service such as a filesystem.
+
+ The ID of the new or updated key is returned if successful.
+
+
+ (*) Search the process's keyrings for a key, potentially calling out to
+ userspace to create it.
+
+ key_serial_t request_key(const char *type, const char *description,
+ const char *callout_info,
+ key_serial_t dest_keyring);
+
+ This function searches all the process's keyrings in the order thread,
+ process, session for a matching key. This works very much like
+ KEYCTL_SEARCH, including the optional attachment of the discovered key to
+ a keyring.
+
+ If a key cannot be found, and if callout_info is not NULL, then
+ /sbin/request-key will be invoked in an attempt to obtain a key. The
+ callout_info string will be passed as an argument to the program.
+
+
+The keyctl syscall functions are:
+
+ (*) Map a special key ID to a real key ID for this process:
+
+ key_serial_t keyctl(KEYCTL_GET_KEYRING_ID, key_serial_t id,
+ int create);
+
+ The special key specified by "id" is looked up (with the key being
+ created if necessary) and the ID of the key or keyring thus found is
+ returned if it exists.
+
+ If the key does not yet exist, the key will be created if "create" is
+ non-zero; and the error ENOKEY will be returned if "create" is zero.
+
+
+ (*) Replace the session keyring this process subscribes to with a new one:
+
+ key_serial_t keyctl(KEYCTL_JOIN_SESSION_KEYRING, const char *name);
+
+ If name is NULL, an anonymous keyring is created attached to the process
+ as its session keyring, displacing the old session keyring.
+
+ If name is not NULL, if a keyring of that name exists, the process
+ attempts to attach it as the session keyring, returning an error if that
+ is not permitted; otherwise a new keyring of that name is created and
+ attached as the session keyring.
+
+ To attach to a named keyring, the keyring must have search permission for
+ the process's ownership.
+
+ The ID of the new session keyring is returned if successful.
+
+
+ (*) Update the specified key:
+
+ long keyctl(KEYCTL_UPDATE, key_serial_t key, const void *payload,
+ size_t plen);
+
+ This will try to update the specified key with the given payload, or it
+ will return error EOPNOTSUPP if that function is not supported by the key
+ type. The process must also have permission to write to the key to be
+ able to update it.
+
+ The payload is of length plen, and may be absent or empty as for
+ add_key().
+
+
+ (*) Revoke a key:
+
+ long keyctl(KEYCTL_REVOKE, key_serial_t key);
+
+ This makes a key unavailable for further operations. Further attempts to
+ use the key will be met with error EKEYREVOKED, and the key will no longer
+ be findable.
+
+
+ (*) Change the ownership of a key:
+
+ long keyctl(KEYCTL_CHOWN, key_serial_t key, uid_t uid, gid_t gid);
+
+ This function permits a key's owner and group ID to be changed. Either
+ one of uid or gid can be set to -1 to suppress that change.
+
+ Only the superuser can change a key's owner to something other than the
+ key's current owner. Similarly, only the superuser can change a key's
+ group ID to something other than the calling process's group ID or one of
+ its group list members.
+
+
+ (*) Change the permissions mask on a key:
+
+ long keyctl(KEYCTL_SETPERM, key_serial_t key, key_perm_t perm);
+
+ This function permits the owner of a key or the superuser to change the
+ permissions mask on a key.
+
+ Only bits the available bits are permitted; if any other bits are set,
+ error EINVAL will be returned.
+
+
+ (*) Describe a key:
+
+ long keyctl(KEYCTL_DESCRIBE, key_serial_t key, char *buffer,
+ size_t buflen);
+
+ This function returns a summary of the key's attributes (but not its
+ payload data) as a string in the buffer provided.
+
+ Unless there's an error, it always returns the amount of data it could
+ produce, even if that's too big for the buffer, but it won't copy more
+ than requested to userspace. If the buffer pointer is NULL then no copy
+ will take place.
+
+ A process must have view permission on the key for this function to be
+ successful.
+
+ If successful, a string is placed in the buffer in the following format:
+
+ <type>;<uid>;<gid>;<perm>;<description>
+
+ Where type and description are strings, uid and gid are decimal, and perm
+ is hexadecimal. A NUL character is included at the end of the string if
+ the buffer is sufficiently big.
+
+ This can be parsed with
+
+ sscanf(buffer, "%[^;];%d;%d;%o;%s", type, &uid, &gid, &mode, desc);
+
+
+ (*) Clear out a keyring:
+
+ long keyctl(KEYCTL_CLEAR, key_serial_t keyring);
+
+ This function clears the list of keys attached to a keyring. The calling
+ process must have write permission on the keyring, and it must be a
+ keyring (or else error ENOTDIR will result).
+
+
+ (*) Link a key into a keyring:
+
+ long keyctl(KEYCTL_LINK, key_serial_t keyring, key_serial_t key);
+
+ This function creates a link from the keyring to the key. The process
+ must have write permission on the keyring and must have link permission
+ on the key.
+
+ Should the keyring not be a keyring, error ENOTDIR will result; and if
+ the keyring is full, error ENFILE will result.
+
+ The link procedure checks the nesting of the keyrings, returning ELOOP if
+ it appears to deep or EDEADLK if the link would introduce a cycle.
+
+
+ (*) Unlink a key or keyring from another keyring:
+
+ long keyctl(KEYCTL_UNLINK, key_serial_t keyring, key_serial_t key);
+
+ This function looks through the keyring for the first link to the
+ specified key, and removes it if found. Subsequent links to that key are
+ ignored. The process must have write permission on the keyring.
+
+ If the keyring is not a keyring, error ENOTDIR will result; and if the
+ key is not present, error ENOENT will be the result.
+
+
+ (*) Search a keyring tree for a key:
+
+ key_serial_t keyctl(KEYCTL_SEARCH, key_serial_t keyring,
+ const char *type, const char *description,
+ key_serial_t dest_keyring);
+
+ This searches the keyring tree headed by the specified keyring until a
+ key is found that matches the type and description criteria. Each keyring
+ is checked for keys before recursion into its children occurs.
+
+ The process must have search permission on the top level keyring, or else
+ error EACCES will result. Only keyrings that the process has search
+ permission on will be recursed into, and only keys and keyrings for which
+ a process has search permission can be matched. If the specified keyring
+ is not a keyring, ENOTDIR will result.
+
+ If the search succeeds, the function will attempt to link the found key
+ into the destination keyring if one is supplied (non-zero ID). All the
+ constraints applicable to KEYCTL_LINK apply in this case too.
+
+ Error ENOKEY, EKEYREVOKED or EKEYEXPIRED will be returned if the search
+ fails. On success, the resulting key ID will be returned.
+
+
+ (*) Read the payload data from a key:
+
+ key_serial_t keyctl(KEYCTL_READ, key_serial_t keyring, char *buffer,
+ size_t buflen);
+
+ This function attempts to read the payload data from the specified key
+ into the buffer. The process must have read permission on the key to
+ succeed.
+
+ The returned data will be processed for presentation by the key type. For
+ instance, a keyring will return an array of key_serial_t entries
+ representing the IDs of all the keys to which it is subscribed. The user
+ defined key type will return its data as is. If a key type does not
+ implement this function, error EOPNOTSUPP will result.
+
+ As much of the data as can be fitted into the buffer will be copied to
+ userspace if the buffer pointer is not NULL.
+
+ On a successful return, the function will always return the amount of
+ data available rather than the amount copied.
+
+
+ (*) Instantiate a partially constructed key.
+
+ key_serial_t keyctl(KEYCTL_INSTANTIATE, key_serial_t key,
+ const void *payload, size_t plen,
+ key_serial_t keyring);
+
+ If the kernel calls back to userspace to complete the instantiation of a
+ key, userspace should use this call to supply data for the key before the
+ invoked process returns, or else the key will be marked negative
+ automatically.
+
+ The process must have write access on the key to be able to instantiate
+ it, and the key must be uninstantiated.
+
+ If a keyring is specified (non-zero), the key will also be linked into
+ that keyring, however all the constraints applying in KEYCTL_LINK apply
+ in this case too.
+
+ The payload and plen arguments describe the payload data as for add_key().
+
+
+ (*) Negatively instantiate a partially constructed key.
+
+ key_serial_t keyctl(KEYCTL_NEGATE, key_serial_t key,
+ unsigned timeout, key_serial_t keyring);
+
+ If the kernel calls back to userspace to complete the instantiation of a
+ key, userspace should use this call mark the key as negative before the
+ invoked process returns if it is unable to fulfil the request.
+
+ The process must have write access on the key to be able to instantiate
+ it, and the key must be uninstantiated.
+
+ If a keyring is specified (non-zero), the key will also be linked into
+ that keyring, however all the constraints applying in KEYCTL_LINK apply
+ in this case too.
+
+
+===============
+KERNEL SERVICES
+===============
+
+The kernel services for key managment are fairly simple to deal with. They can
+be broken down into two areas: keys and key types.
+
+Dealing with keys is fairly straightforward. Firstly, the kernel service
+registers its type, then it searches for a key of that type. It should retain
+the key as long as it has need of it, and then it should release it. For a
+filesystem or device file, a search would probably be performed during the
+open call, and the key released upon close. How to deal with conflicting keys
+due to two different users opening the same file is left to the filesystem
+author to solve.
+
+When accessing a key's payload data, the key->lock should be at least read
+locked, or else the data may be changed by update during the access.
+
+(*) To search for a key, call:
+
+ struct key *request_key(const struct key_type *type,
+ const char *description,
+ const char *callout_string);
+
+ This is used to request a key or keyring with a description that matches
+ the description specified according to the key type's match function. This
+ permits approximate matching to occur. If callout_string is not NULL, then
+ /sbin/request-key will be invoked in an attempt to obtain the key from
+ userspace. In that case, callout_string will be passed as an argument to
+ the program.
+
+ Should the function fail error ENOKEY, EKEYEXPIRED or EKEYREVOKED will be
+ returned.
+
+
+(*) When it is no longer required, the key should be released using:
+
+ void key_put(struct key *key);
+
+ This can be called from interrupt context. If CONFIG_KEYS is not set then
+ the argument will not be parsed.
+
+
+(*) Extra references can be made to a key by calling the following function:
+
+ struct key *key_get(struct key *key);
+
+ These need to be disposed of by calling key_put() when they've been
+ finished with. The key pointer passed in will be returned. If the pointer
+ is NULL or CONFIG_KEYS is not set then the key will not be dereferenced and
+ no increment will take place.
+
+
+(*) A key's serial number can be obtained by calling:
+
+ key_serial_t key_serial(struct key *key);
+
+ If key is NULL or if CONFIG_KEYS is not set then 0 will be returned (in the
+ latter case without parsing the argument).
+
+
+(*) If a keyring was found in the search, this can be further searched by:
+
+ struct key *keyring_search(struct key *keyring,
+ const struct key_type *type,
+ const char *description)
+
+ This searches the keyring tree specified for a matching key. Error ENOKEY
+ is returned upon failure. If successful, the returned key will need to be
+ released.
+
+
+(*) To check the validity of a key, this function can be called:
+
+ int validate_key(struct key *key);
+
+ This checks that the key in question hasn't expired or and hasn't been
+ revoked. Should the key be invalid, error EKEYEXPIRED or EKEYREVOKED will
+ be returned. If the key is NULL or if CONFIG_KEYS is not set then 0 will be
+ returned (in the latter case without parsing the argument).
+
+
+(*) To register a key type, the following function should be called:
+
+ int register_key_type(struct key_type *type);
+
+ This will return error EEXIST if a type of the same name is already
+ present.
+
+
+(*) To unregister a key type, call:
+
+ void unregister_key_type(struct key_type *type);
+
+
+===================
+DEFINING A KEY TYPE
+===================
+
+A kernel service may want to define its own key type. For instance, an AFS
+filesystem might want to define a Kerberos 5 ticket key type. To do this, it
+author fills in a struct key_type and registers it with the system.
+
+The structure has a number of fields, some of which are mandatory:
+
+ (*) const char *name
+
+ The name of the key type. This is used to translate a key type name
+ supplied by userspace into a pointer to the structure.
+
+
+ (*) size_t def_datalen
+
+ This is optional - it supplies the default payload data length as
+ contributed to the quota. If the key type's payload is always or almost
+ always the same size, then this is a more efficient way to do things.
+
+ The data length (and quota) on a particular key can always be changed
+ during instantiation or update by calling:
+
+ int key_payload_reserve(struct key *key, size_t datalen);
+
+ With the revised data length. Error EDQUOT will be returned if this is
+ not viable.
+
+
+ (*) int (*instantiate)(struct key *key, const void *data, size_t datalen);
+
+ This method is called to attach a payload to a key during
+ construction. The payload attached need not bear any relation to the data
+ passed to this function.
+
+ If the amount of data attached to the key differs from the size in
+ keytype->def_datalen, then key_payload_reserve() should be called.
+
+
+ (*) int (*duplicate)(struct key *key, const struct key *source);
+
+ If this type of key can be duplicated, then this method should be
+ provided. It is called to copy the payload attached to the source into
+ the new key. The data length on the new key will have been updated and
+ the quota adjusted already.
+
+ The source key will be locked against change on the source->sem, so it is
+ safe to sleep here.
+
+
+ (*) int (*update)(struct key *key, const void *data, size_t datalen);
+
+ If this type of key can be updated, then this method should be
+ provided. It is called to update a key's payload from the blob of data
+ provided.
+
+ key_payload_reserve() should be called if the data length might change
+ before any changes are actually made. Note that if this succeeds, the
+ type is committed to changing the key because it's already been altered,
+ so all memory allocation must be done first.
+
+ The key will be locked against other changers on key->sem, so it is safe
+ to sleep here.
+
+ key_payload_reserve() should be called with the key->lock write locked,
+ and the changes to the key's attached payload should be made before the
+ key is locked.
+
+
+ (*) int (*match)(const struct key *key, const void *desc);
+
+ This method is called to match a key against a description. It should
+ return non-zero if the two match, zero if they don't.
+
+
+ (*) void (*destroy)(struct key *key);
+
+ This method is optional. It is called to discard the payload data on a
+ key when it is being destroyed.
+
+
+ (*) void (*describe)(const struct key *key, struct seq_file *p);
+
+ This method is optional. It is called during /proc/keys reading to
+ summarise a key in text form.
+
+
+ (*) long (*read)(const struct key *key, char __user *buffer, size_t buflen);
+
+ This method is optional. It is called by KEYCTL_READ to translate the
+ key's payload into something a blob of data for userspace to deal
+ with. Ideally, the blob should be in the same format as that passed in to
+ the instantiate and update methods.
+
+ If successful, the blob size that could be produced should be returned
+ rather than the size copied.
+
+
+============================
+REQUEST-KEY CALLBACK SERVICE
+============================
+
+To create a new key, the kernel will attempt to execute the following command
+line:
+
+ /sbin/request-key create <key> <uid> <gid> \
+ <threadring> <processring> <sessionring> <callout_info>
+
+<key> is the key being constructed, and the three keyrings are the process
+keyrings from the process that caused the search to be issued. These are
+included for two reasons:
+
+ (1) There may be an authentication token in one of the keyrings that is
+ required to obtain the key, eg: a Kerberos Ticket-Granting Ticket.
+
+ (2) The new key should probably be cached in one of these rings.
+
+This program should set it UID and GID to those specified before attempting to
+access any more keys. It may then look around for a user specific process to
+hand the request off to (perhaps a path held in placed in another key by, for
+example, the KDE desktop manager).
+
+The program (or whatever it calls) should finish construction of the key by
+calling KEYCTL_INSTANTIATE, which also permits it to cache the key in one of
+the keyrings (probably the session ring) before returning. Alternatively, the
+key can be marked as negative with KEYCTL_NEGATE; this also permits the key to
+be cached in one of the keyrings.
+
+If it returns with the key remaining in the unconstructed state, the key will
+be marked as being negative, it will be added to the session keyring, and an
+error will be returned to the key requestor.
+
+Supplementary information may be provided from whoever or whatever invoked
+this service. This will be passed as the <callout_info> parameter. If no such
+information was made available, then "-" will be passed as this parameter
+instead.
+
+
+Similarly, the kernel may attempt to update an expired or a soon to expire key
+by executing:
+
+ /sbin/request-key update <key> <uid> <gid> \
+ <threadring> <processring> <sessionring>
+
+In this case, the program isn't required to actually attach the key to a ring;
+the rings are provided for reference.
.long sys_mq_getsetattr
.long sys_ni_syscall /* reserved for kexec */
.long sys_waitid
- .long sys_setaltroot
+ .long sys_setaltroot /* 285 */
+ .long sys_add_key
+ .long sys_request_key
+ .long sys_keyctl
syscall_table_size=(.-sys_call_table)
goto error;
#endif
-#ifdef CONFIG_KEYS
+#ifdef CONFIG_KEYS_TURNED_OFF
ret = afs_key_register();
if (ret < 0)
goto error_cache;
error_kafstimod:
afs_kafstimod_stop();
error_keys:
-#ifdef CONFIG_KEYS
+#ifdef CONFIG_KEYS_TURNED_OFF
afs_key_unregister();
error_cache:
#endif
afs_kafstimod_stop();
afs_kafsasyncd_stop();
afs_cell_purge();
-#ifdef CONFIG_KEYS
+#ifdef CONFIG_KEYS_TURNED_OFF
afs_key_unregister();
#endif
#ifdef AFS_CACHING_SUPPORT
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/spinlock.h>
+#include <linux/key.h>
#include <linux/personality.h>
#include <linux/binfmts.h>
#include <linux/swap.h>
if (bprm->e_uid != current->euid || bprm->e_gid != current->egid ||
permission(bprm->file->f_dentry->d_inode,MAY_READ, NULL) ||
- (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP))
+ (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
+ suid_keys(current);
current->mm->dumpable = 0;
+ }
/* An exec changes our domain. We are no longer part of the thread
group */
void compute_creds(struct linux_binprm *bprm)
{
int unsafe;
+
+ if (bprm->e_uid != current->uid)
+ suid_keys(current);
+ exec_keys(current);
+
task_lock(current);
unsafe = unsafe_exec(current);
security_bprm_apply_creds(bprm, unsafe);
#define __NR_sys_kexec_load 283
#define __NR_waitid 284
#define __NR_sys_setaltroot 285
+#define __NR_add_key 286
+#define __NR_request_key 287
+#define __NR_keyctl 288
-#define NR_syscalls 286
-
-/* user-visible error numbers are in the range -1 - -124: see <asm-i386/errno.h> */
+#define NR_syscalls 289
+/*
+ * user-visible error numbers are in the range -1 - -128: see
+ * <asm-i386/errno.h>
+ */
#define __syscall_return(type, res) \
do { \
- if ((unsigned long)(res) >= (unsigned long)(-125)) { \
+ if ((unsigned long)(res) >= (unsigned long)(-(128 + 1))) { \
errno = -(res); \
res = -1; \
} \
--- /dev/null
+/* key-ui.h: key userspace interface stuff for use by keyfs
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _LINUX_KEY_UI_H
+#define _LINUX_KEY_UI_H
+
+#include <linux/key.h>
+
+/* the key tree */
+extern struct rb_root key_serial_tree;
+extern spinlock_t key_serial_lock;
+
+/* required permissions */
+#define KEY_VIEW 0x01 /* require permission to view attributes */
+#define KEY_READ 0x02 /* require permission to read content */
+#define KEY_WRITE 0x04 /* require permission to update / modify */
+#define KEY_SEARCH 0x08 /* require permission to search (keyring) or find (key) */
+#define KEY_LINK 0x10 /* require permission to link */
+#define KEY_ALL 0x1f /* all the above permissions */
+
+/*
+ * the keyring payload contains a list of the keys to which the keyring is
+ * subscribed
+ */
+struct keyring_list {
+ unsigned maxkeys; /* max keys this list can hold */
+ unsigned nkeys; /* number of keys currently held */
+ struct key *keys[0];
+};
+
+
+/*
+ * check to see whether permission is granted to use a key in the desired way
+ */
+static inline int key_permission(const struct key *key, key_perm_t perm)
+{
+ key_perm_t kperm;
+
+ if (key->uid == current->fsuid)
+ kperm = key->perm >> 16;
+ else if (key->gid != -1 &&
+ key->perm & KEY_GRP_ALL &&
+ in_group_p(key->gid)
+ )
+ kperm = key->perm >> 8;
+ else
+ kperm = key->perm;
+
+ kperm = kperm & perm & KEY_ALL;
+
+ return kperm == perm;
+}
+
+/*
+ * check to see whether permission is granted to use a key in at least one of
+ * the desired ways
+ */
+static inline int key_any_permission(const struct key *key, key_perm_t perm)
+{
+ key_perm_t kperm;
+
+ if (key->uid == current->fsuid)
+ kperm = key->perm >> 16;
+ else if (key->gid != -1 &&
+ key->perm & KEY_GRP_ALL &&
+ in_group_p(key->gid)
+ )
+ kperm = key->perm >> 8;
+ else
+ kperm = key->perm;
+
+ kperm = kperm & perm & KEY_ALL;
+
+ return kperm != 0;
+}
+
+
+extern struct key *lookup_user_key(key_serial_t id, int create, int part,
+ key_perm_t perm);
+
+extern long join_session_keyring(const char *name);
+
+extern struct key_type *key_type_lookup(const char *type);
+extern void key_type_put(struct key_type *ktype);
+
+#define key_negative_timeout 60 /* default timeout on a negative key's existence */
+
+
+#endif /* _LINUX_KEY_UI_H */
--- /dev/null
+/* key.h: authentication token and access key management
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ *
+ * See Documentation/keys.txt for information on keys/keyrings.
+ */
+
+#ifndef _LINUX_KEY_H
+#define _LINUX_KEY_H
+
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/rbtree.h>
+#include <linux/spinlock.h>
+#include <asm/atomic.h>
+
+#ifdef __KERNEL__
+
+/* key handle serial number */
+typedef int32_t key_serial_t;
+
+/* key handle permissions mask */
+typedef uint32_t key_perm_t;
+
+struct key;
+
+#ifdef CONFIG_KEYS
+
+#undef KEY_DEBUGGING
+
+#define KEY_USR_VIEW 0x00010000 /* user can view a key's attributes */
+#define KEY_USR_READ 0x00020000 /* user can read key payload / view keyring */
+#define KEY_USR_WRITE 0x00040000 /* user can update key payload / add link to keyring */
+#define KEY_USR_SEARCH 0x00080000 /* user can find a key in search / search a keyring */
+#define KEY_USR_LINK 0x00100000 /* user can create a link to a key/keyring */
+#define KEY_USR_ALL 0x001f0000
+
+#define KEY_GRP_VIEW 0x00000100 /* group permissions... */
+#define KEY_GRP_READ 0x00000200
+#define KEY_GRP_WRITE 0x00000400
+#define KEY_GRP_SEARCH 0x00000800
+#define KEY_GRP_LINK 0x00001000
+#define KEY_GRP_ALL 0x00001f00
+
+#define KEY_OTH_VIEW 0x00000001 /* third party permissions... */
+#define KEY_OTH_READ 0x00000002
+#define KEY_OTH_WRITE 0x00000004
+#define KEY_OTH_SEARCH 0x00000008
+#define KEY_OTH_LINK 0x00000010
+#define KEY_OTH_ALL 0x0000001f
+
+struct seq_file;
+struct user_struct;
+
+struct key_type;
+struct key_owner;
+struct keyring_list;
+struct keyring_name;
+
+/*****************************************************************************/
+/*
+ * authentication token / access credential / keyring
+ * - types of key include:
+ * - keyrings
+ * - disk encryption IDs
+ * - Kerberos TGTs and tickets
+ */
+struct key {
+ atomic_t usage; /* number of references */
+ key_serial_t serial; /* key serial number */
+ struct rb_node serial_node;
+ struct key_type *type; /* type of key */
+ rwlock_t lock; /* examination vs change lock */
+ struct rw_semaphore sem; /* change vs change sem */
+ struct key_user *user; /* owner of this key */
+ time_t expiry; /* time at which key expires (or 0) */
+ uid_t uid;
+ gid_t gid;
+ key_perm_t perm; /* access permissions */
+ unsigned short quotalen; /* length added to quota */
+ unsigned short datalen; /* payload data length */
+ unsigned short flags; /* status flags (change with lock writelocked) */
+#define KEY_FLAG_INSTANTIATED 0x00000001 /* set if key has been instantiated */
+#define KEY_FLAG_DEAD 0x00000002 /* set if key type has been deleted */
+#define KEY_FLAG_REVOKED 0x00000004 /* set if key had been revoked */
+#define KEY_FLAG_IN_QUOTA 0x00000008 /* set if key consumes quota */
+#define KEY_FLAG_USER_CONSTRUCT 0x00000010 /* set if key is being constructed in userspace */
+#define KEY_FLAG_NEGATIVE 0x00000020 /* set if key is negative */
+
+#ifdef KEY_DEBUGGING
+ unsigned magic;
+#define KEY_DEBUG_MAGIC 0x18273645u
+#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
+#endif
+
+ /* the description string
+ * - this is used to match a key against search criteria
+ * - this should be a printable string
+ * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
+ */
+ char *description;
+
+ /* type specific data
+ * - this is used by the keyring type to index the name
+ */
+ union {
+ struct list_head link;
+ } type_data;
+
+ /* key data
+ * - this is used to hold the data actually used in cryptography or
+ * whatever
+ */
+ union {
+ unsigned long value;
+ void *data;
+ struct keyring_list *subscriptions;
+ } payload;
+};
+
+/*****************************************************************************/
+/*
+ * kernel managed key type definition
+ */
+struct key_type {
+ /* name of the type */
+ const char *name;
+
+ /* default payload length for quota precalculation (optional)
+ * - this can be used instead of calling key_payload_reserve(), that
+ * function only needs to be called if the real datalen is different
+ */
+ size_t def_datalen;
+
+ /* instantiate a key of this type
+ * - this method should call key_payload_reserve() to determine if the
+ * user's quota will hold the payload
+ */
+ int (*instantiate)(struct key *key, const void *data, size_t datalen);
+
+ /* duplicate a key of this type (optional)
+ * - the source key will be locked against change
+ * - the new description will be attached
+ * - the quota will have been adjusted automatically from
+ * source->quotalen
+ */
+ int (*duplicate)(struct key *key, const struct key *source);
+
+ /* update a key of this type (optional)
+ * - this method should call key_payload_reserve() to recalculate the
+ * quota consumption
+ * - the key must be locked against read when modifying
+ */
+ int (*update)(struct key *key, const void *data, size_t datalen);
+
+ /* match a key against a description */
+ int (*match)(const struct key *key, const void *desc);
+
+ /* clear the data from a key (optional) */
+ void (*destroy)(struct key *key);
+
+ /* describe a key */
+ void (*describe)(const struct key *key, struct seq_file *p);
+
+ /* read a key's data (optional)
+ * - permission checks will be done by the caller
+ * - the key's semaphore will be readlocked by the caller
+ * - should return the amount of data that could be read, no matter how
+ * much is copied into the buffer
+ * - shouldn't do the copy if the buffer is NULL
+ */
+ long (*read)(const struct key *key, char __user *buffer, size_t buflen);
+
+ /* internal fields */
+ struct list_head link; /* link in types list */
+};
+
+extern struct key_type key_type_keyring;
+
+extern int register_key_type(struct key_type *ktype);
+extern void unregister_key_type(struct key_type *ktype);
+
+extern struct key *key_alloc(struct key_type *type,
+ const char *desc,
+ uid_t uid, gid_t gid, key_perm_t perm,
+ int not_in_quota);
+extern int key_payload_reserve(struct key *key, size_t datalen);
+extern int key_instantiate_and_link(struct key *key,
+ const void *data,
+ size_t datalen,
+ struct key *keyring);
+extern int key_negate_and_link(struct key *key,
+ unsigned timeout,
+ struct key *keyring);
+extern void key_revoke(struct key *key);
+extern void key_put(struct key *key);
+
+static inline struct key *key_get(struct key *key)
+{
+ if (key)
+ atomic_inc(&key->usage);
+ return key;
+}
+
+extern struct key *request_key(struct key_type *type,
+ const char *description,
+ const char *callout_info);
+
+extern int key_validate(struct key *key);
+
+extern struct key *key_create_or_update(struct key *keyring,
+ const char *type,
+ const char *description,
+ const void *payload,
+ size_t plen,
+ int not_in_quota);
+
+extern int key_update(struct key *key,
+ const void *payload,
+ size_t plen);
+
+extern int key_link(struct key *keyring,
+ struct key *key);
+
+extern int key_unlink(struct key *keyring,
+ struct key *key);
+
+extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
+ int not_in_quota, struct key *dest);
+
+extern int keyring_clear(struct key *keyring);
+
+extern struct key *keyring_search(struct key *keyring,
+ struct key_type *type,
+ const char *description);
+
+extern struct key *search_process_keyrings(struct key_type *type,
+ const char *description);
+
+extern int keyring_add_key(struct key *keyring,
+ struct key *key);
+
+extern struct key *key_lookup(key_serial_t id);
+
+#define key_serial(key) ((key) ? (key)->serial : 0)
+
+/*
+ * the userspace interface
+ */
+extern struct key root_user_keyring, root_session_keyring;
+extern int alloc_uid_keyring(struct user_struct *user);
+extern void switch_uid_keyring(struct user_struct *new_user);
+extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
+extern void exit_keys(struct task_struct *tsk);
+extern int suid_keys(struct task_struct *tsk);
+extern int exec_keys(struct task_struct *tsk);
+extern void key_fsuid_changed(struct task_struct *tsk);
+extern void key_fsgid_changed(struct task_struct *tsk);
+
+#else /* CONFIG_KEYS */
+
+#define key_validate(k) 0
+#define key_serial(k) 0
+#define key_get(k) NULL
+#define key_put(k) do { } while(0)
+#define alloc_uid_keyring(u) 0
+#define switch_uid_keyring(u) do { } while(0)
+#define copy_keys(f,t) 0
+#define exit_keys(t) do { } while(0)
+#define suid_keys(t) do { } while(0)
+#define exec_keys(t) do { } while(0)
+#define key_fsuid_changed(t) do { } while(0)
+#define key_fsgid_changed(t) do { } while(0)
+
+#endif /* CONFIG_KEYS */
+#endif /* __KERNEL__ */
+#endif /* _LINUX_KEY_H */
--- /dev/null
+/* keyctl.h: keyctl command IDs
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _LINUX_KEYCTL_H
+#define _LINUX_KEYCTL_H
+
+/* special process keyring shortcut IDs */
+#define KEY_SPEC_THREAD_KEYRING -1 /* - key ID for thread-specific keyring */
+#define KEY_SPEC_PROCESS_KEYRING -2 /* - key ID for process-specific keyring */
+#define KEY_SPEC_SESSION_KEYRING -3 /* - key ID for session-specific keyring */
+#define KEY_SPEC_USER_KEYRING -4 /* - key ID for UID-specific keyring */
+#define KEY_SPEC_USER_SESSION_KEYRING -5 /* - key ID for UID-session keyring */
+#define KEY_SPEC_GROUP_KEYRING -6 /* - key ID for GID-specific keyring */
+
+/* keyctl commands */
+#define KEYCTL_GET_KEYRING_ID 0 /* ask for a keyring's ID */
+#define KEYCTL_JOIN_SESSION_KEYRING 1 /* join or start named session keyring */
+#define KEYCTL_UPDATE 2 /* update a key */
+#define KEYCTL_REVOKE 3 /* revoke a key */
+#define KEYCTL_CHOWN 4 /* set ownership of a key */
+#define KEYCTL_SETPERM 5 /* set perms on a key */
+#define KEYCTL_DESCRIBE 6 /* describe a key */
+#define KEYCTL_CLEAR 7 /* clear contents of a keyring */
+#define KEYCTL_LINK 8 /* link a key into a keyring */
+#define KEYCTL_UNLINK 9 /* unlink a key from a keyring */
+#define KEYCTL_SEARCH 10 /* search for a key in a keyring */
+#define KEYCTL_READ 11 /* read a key or keyring's contents */
+#define KEYCTL_INSTANTIATE 12 /* instantiate a partially constructed key */
+#define KEYCTL_NEGATE 13 /* negate a partially constructed key */
+
+#endif /* _LINUX_KEYCTL_H */
# define PR_TIMING_TIMESTAMP 1 /* Accurate timestamp based
process timing */
-
#define PR_SET_NAME 15 /* Set process name */
#endif /* _LINUX_PRCTL_H */
unsigned long mq_bytes; /* How many bytes can be allocated to mqueue? */
unsigned long locked_shm; /* How many pages of mlocked shm ? */
+#ifdef CONFIG_KEYS
+ struct key *uid_keyring; /* UID specific keyring */
+ struct key *session_keyring; /* UID's default session keyring */
+#endif
+
/* Hash table maintenance information */
struct list_head uidhash_list;
uid_t uid;
kernel_cap_t cap_effective, cap_inheritable, cap_permitted;
unsigned keep_capabilities:1;
struct user_struct *user;
+#ifdef CONFIG_KEYS
+ struct key *session_keyring; /* keyring inherited over fork */
+ struct key *process_keyring; /* keyring private to this process (CLONE_THREAD) */
+ struct key *thread_keyring; /* keyring private to this thread */
+#endif
unsigned short used_math;
char comm[16];
/* file system info */
/* Thread group tracking */
u32 parent_exec_id;
u32 self_exec_id;
-/* Protection of (de-)allocation: mm, files, fs, tty */
+/* Protection of (de-)allocation: mm, files, fs, tty, keyrings */
spinlock_t alloc_lock;
/* Protection of proc_dentry: nesting proc_lock, dcache_lock, write_lock_irq(&tasklist_lock); */
spinlock_t proc_lock;
extern void unhash_process(struct task_struct *p);
/*
- * Protects ->fs, ->files, ->mm, ->ptrace, ->group_info, ->comm and
- * synchronises with wait4().
+ * Protects ->fs, ->files, ->mm, ->ptrace, ->group_info, ->comm, keyring
+ * subscriptions and synchronises with wait4(). Also used in procfs.
*
* Nests both inside and outside of read_lock(&tasklist_lock).
* It must not be nested with write_lock_irq(&tasklist_lock),
#include <asm/siginfo.h>
#include <asm/signal.h>
#include <linux/quota.h>
+#include <linux/key.h>
asmlinkage long sys_time(int __user *tloc);
asmlinkage long sys_stime(time_t __user *tptr);
asmlinkage long sys_setaltroot(const char __user *altroot);
asmlinkage long sys_ni_syscall(void);
+asmlinkage long sys_add_key(const char __user *_type,
+ const char __user *_description,
+ const void __user *_payload,
+ size_t plen,
+ key_serial_t destringid);
+
+asmlinkage long sys_request_key(const char __user *_type,
+ const char __user *_description,
+ const char __user *_callout_info,
+ key_serial_t destringid);
+
+asmlinkage long sys_keyctl(int cmd, unsigned long arg2, unsigned long arg3,
+ unsigned long arg4, unsigned long arg5);
+
#endif
#include <linux/personality.h>
#include <linux/tty.h>
#include <linux/namespace.h>
+#include <linux/key.h>
#include <linux/security.h>
#include <linux/cpu.h>
#include <linux/acct.h>
__exit_fs(tsk);
exit_namespace(tsk);
exit_thread();
+ exit_keys(tsk);
if (tsk->signal->leader)
disassociate_ctty(1);
#include <linux/mempolicy.h>
#include <linux/sem.h>
#include <linux/file.h>
+#include <linux/key.h>
#include <linux/binfmts.h>
#include <linux/mman.h>
#include <linux/fs.h>
}
#endif
+ p->tgid = p->pid;
+ if (clone_flags & CLONE_THREAD)
+ p->tgid = current->tgid;
+
if ((retval = security_task_alloc(p)))
goto bad_fork_cleanup_policy;
if ((retval = audit_alloc(p)))
goto bad_fork_cleanup_sighand;
if ((retval = copy_mm(clone_flags, p)))
goto bad_fork_cleanup_signal;
- if ((retval = copy_namespace(clone_flags, p)))
+ if ((retval = copy_keys(clone_flags, p)))
goto bad_fork_cleanup_mm;
+ if ((retval = copy_namespace(clone_flags, p)))
+ goto bad_fork_cleanup_keys;
retval = copy_thread(0, clone_flags, stack_start, stack_size, p, regs);
if (retval)
goto bad_fork_cleanup_namespace;
* Ok, make it visible to the rest of the system.
* We dont wake it up yet.
*/
- p->tgid = p->pid;
p->group_leader = p;
INIT_LIST_HEAD(&p->ptrace_children);
INIT_LIST_HEAD(&p->ptrace_list);
retval = -EAGAIN;
goto bad_fork_cleanup_namespace;
}
- p->tgid = current->tgid;
p->group_leader = current->group_leader;
if (current->signal->group_stop_count > 0) {
bad_fork_cleanup_namespace:
exit_namespace(p);
+bad_fork_cleanup_keys:
+ exit_keys(p);
bad_fork_cleanup_mm:
if (p->mm)
mmput(p->mm);
#include <linux/fs.h>
#include <linux/workqueue.h>
#include <linux/device.h>
+#include <linux/key.h>
#include <linux/times.h>
#include <linux/security.h>
#include <linux/dcookies.h>
cond_syscall(compat_mbind)
cond_syscall(compat_get_mempolicy)
cond_syscall(compat_set_mempolicy)
+cond_syscall(sys_add_key)
+cond_syscall(sys_request_key)
+cond_syscall(sys_keyctl)
/* arch-specific weak syscall entries */
cond_syscall(sys_pciconfig_read)
current->fsgid = new_egid;
current->egid = new_egid;
current->gid = new_rgid;
+ key_fsgid_changed(current);
return 0;
}
}
else
return -EPERM;
+
+ key_fsgid_changed(current);
return 0;
}
current->suid = current->euid;
current->fsuid = current->euid;
+ key_fsuid_changed(current);
+
return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RE);
}
current->fsuid = current->euid = uid;
current->suid = new_suid;
+ key_fsuid_changed(current);
+
return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_ID);
}
if (suid != (uid_t) -1)
current->suid = suid;
+ key_fsuid_changed(current);
+
return security_task_post_setuid(old_ruid, old_euid, old_suid, LSM_SETID_RES);
}
current->gid = rgid;
if (sgid != (gid_t) -1)
current->sgid = sgid;
+
+ key_fsgid_changed(current);
return 0;
}
current->fsuid = uid;
}
+ key_fsuid_changed(current);
+
security_task_post_setuid(old_fsuid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS);
return old_fsuid;
wmb();
}
current->fsgid = gid;
+ key_fsgid_changed(current);
}
return old_fsgid;
}
asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
unsigned long arg4, unsigned long arg5)
{
- int error;
+ long error;
int sig;
error = security_task_prctl(option, arg2, arg3, arg4, arg5);
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/bitops.h>
+#include <linux/key.h>
/*
* UID task count cache, to get fast user lookup in "alloc_uid"
.sigpending = ATOMIC_INIT(0),
.mq_bytes = 0,
.locked_shm = 0,
+#ifdef CONFIG_KEYS
+ .uid_keyring = &root_user_keyring,
+ .session_keyring = &root_session_keyring,
+#endif
};
/*
{
if (up && atomic_dec_and_lock(&up->__count, &uidhash_lock)) {
uid_hash_remove(up);
+ key_put(up->uid_keyring);
+ key_put(up->session_keyring);
kmem_cache_free(uid_cachep, up);
spin_unlock(&uidhash_lock);
}
new->mq_bytes = 0;
new->locked_shm = 0;
+ if (alloc_uid_keyring(new) < 0) {
+ kmem_cache_free(uid_cachep, new);
+ return NULL;
+ }
+
/*
* Before adding this, check whether we raced
* on adding the same user already..
spin_lock(&uidhash_lock);
up = uid_hash_find(uid, hashent);
if (up) {
+ key_put(new->uid_keyring);
+ key_put(new->session_keyring);
kmem_cache_free(uid_cachep, new);
} else {
uid_hash_insert(new, hashent);
old_user = current->user;
atomic_inc(&new_user->processes);
atomic_dec(&old_user->processes);
+ switch_uid_keyring(new_user);
current->user = new_user;
free_uid(old_user);
+ suid_keys(current);
}
menu "Security options"
+config KEYS
+ bool "Enable access key retention support"
+ help
+ This option provides support for retaining authentication tokens and
+ access keys in the kernel.
+
+ It also includes provision of methods by which such keys might be
+ associated with a process so that network filesystems, encryption
+ support and the like can find them.
+
+ Furthermore, a special type of key is available that acts as keyring:
+ a searchable sequence of keys. Each process is equipped with access
+ to five standard keyrings: UID-specific, GID-specific, session,
+ process and thread.
+
+ If you are unsure as to whether this is required, answer N.
+
+config KEYS_DEBUG_PROC_KEYS
+ bool "Enable the /proc/keys file by which all keys may be viewed"
+ depends on KEYS
+ help
+ This option turns on support for the /proc/keys file through which
+ all the keys on the system can be listed.
+
+ This option is a slight security risk in that it makes it possible
+ for anyone to see all the keys on the system. Normally the manager
+ pretends keys that are inaccessible to a process don't exist as far
+ as that process is concerned.
+
config SECURITY
bool "Enable different security models"
help
# Makefile for the kernel security code
#
+obj-$(CONFIG_KEYS) += keys/
subdir-$(CONFIG_SECURITY_SELINUX) += selinux
# if we don't select a security model, use the default capabilities
--- /dev/null
+#
+# Makefile for key management
+#
+
+obj-y := \
+ key.o \
+ keyring.o \
+ keyctl.o \
+ process_keys.o \
+ user_defined.o \
+ request_key.o
+
+obj-$(CONFIG_PROC_FS) += proc.o
--- /dev/null
+/* internal.h: authentication token and access key management internal defs
+ *
+ * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#ifndef _INTERNAL_H
+#define _INTERNAL_H
+
+#include <linux/key.h>
+#include <linux/key-ui.h>
+
+extern struct key_type key_type_dead;
+extern struct key_type key_type_user;
+
+/*****************************************************************************/
+/*
+ * keep track of keys for a user
+ * - this needs to be separate to user_struct to avoid a refcount-loop
+ * (user_struct pins some keyrings which pin this struct)
+ * - this also keeps track of keys under request from userspace for this UID
+ */
+struct key_user {
+ struct rb_node node;
+ struct list_head consq; /* construction queue */
+ spinlock_t lock;
+ atomic_t usage; /* for accessing qnkeys & qnbytes */
+ atomic_t nkeys; /* number of keys */
+ atomic_t nikeys; /* number of instantiated keys */
+ uid_t uid;
+ int qnkeys; /* number of keys allocated to this user */
+ int qnbytes; /* number of bytes allocated to this user */
+};
+
+#define KEYQUOTA_MAX_KEYS 100
+#define KEYQUOTA_MAX_BYTES 10000
+#define KEYQUOTA_LINK_BYTES 4 /* a link in a keyring is worth 4 bytes */
+
+extern struct rb_root key_user_tree;
+extern spinlock_t key_user_lock;
+extern struct key_user root_key_user;
+
+extern struct key_user *key_user_lookup(uid_t uid);
+extern void key_user_put(struct key_user *user);
+
+
+
+extern struct rb_root key_serial_tree;
+extern spinlock_t key_serial_lock;
+extern struct semaphore key_alloc_sem;
+extern struct rw_semaphore key_construction_sem;
+extern wait_queue_head_t request_key_conswq;
+
+
+extern void keyring_publish_name(struct key *keyring);
+
+extern int __key_link(struct key *keyring, struct key *key);
+
+extern struct key *__keyring_search_one(struct key *keyring,
+ const struct key_type *type,
+ const char *description,
+ key_perm_t perm);
+
+typedef int (*key_match_func_t)(const struct key *, const void *);
+
+extern struct key *keyring_search_aux(struct key *keyring,
+ struct key_type *type,
+ const void *description,
+ key_match_func_t match);
+
+extern struct key *search_process_keyrings_aux(struct key_type *type,
+ const void *description,
+ key_match_func_t match);
+
+extern struct key *find_keyring_by_name(const char *name, key_serial_t bound);
+
+extern int install_thread_keyring(struct task_struct *tsk);
+
+
+/*
+ * debugging key validation
+ */
+#ifdef KEY_DEBUGGING
+static void __key_check(const struct key *key)
+{
+ printk("__key_check: key %p {%08x} should be {%08x}\n",
+ key, key->magic, KEY_DEBUG_MAGIC);
+ BUG();
+}
+
+
+static inline void key_check(const struct key *key)
+{
+ if (key && (IS_ERR(key) || key->magic != KEY_DEBUG_MAGIC))
+ __key_check(key);
+}
+
+#else
+
+#define key_check(key) do {} while(0)
+
+#endif
+
+#endif /* _INTERNAL_H */
--- /dev/null
+/* key.c: basic authentication token and access key management
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+#include <linux/err.h>
+#include "internal.h"
+
+static kmem_cache_t *key_jar;
+static key_serial_t key_serial_next = 3;
+struct rb_root key_serial_tree; /* tree of keys indexed by serial */
+spinlock_t key_serial_lock = SPIN_LOCK_UNLOCKED;
+
+struct rb_root key_user_tree; /* tree of quota records indexed by UID */
+spinlock_t key_user_lock = SPIN_LOCK_UNLOCKED;
+
+static LIST_HEAD(key_types_list);
+static DECLARE_RWSEM(key_types_sem);
+
+static void key_cleanup(void *data);
+static DECLARE_WORK(key_cleanup_task, key_cleanup, NULL);
+
+/* we serialise key instantiation and link */
+DECLARE_RWSEM(key_construction_sem);
+
+/* any key who's type gets unegistered will be re-typed to this */
+struct key_type key_type_dead = {
+ .name = "dead",
+};
+
+/*****************************************************************************/
+/*
+ * get the key quota record for a user, allocating a new record if one doesn't
+ * already exist
+ */
+struct key_user *key_user_lookup(uid_t uid)
+{
+ struct key_user *candidate = NULL, *user;
+ struct rb_node *parent = NULL;
+ struct rb_node **p = &key_user_tree.rb_node;
+
+ try_again:
+ spin_lock(&key_user_lock);
+
+ /* search the tree for a user record with a matching UID */
+ while (*p) {
+ parent = *p;
+ user = rb_entry(parent, struct key_user, node);
+
+ if (uid < user->uid)
+ p = &(*p)->rb_left;
+ else if (uid > user->uid)
+ p = &(*p)->rb_right;
+ else
+ goto found;
+ }
+
+ /* if we get here, we failed to find a match in the tree */
+ if (!candidate) {
+ /* allocate a candidate user record if we don't already have
+ * one */
+ spin_unlock(&key_user_lock);
+
+ user = NULL;
+ candidate = kmalloc(sizeof(struct key_user), GFP_KERNEL);
+ if (unlikely(!candidate))
+ goto out;
+
+ /* the allocation may have scheduled, so we need to repeat the
+ * search lest someone else added the record whilst we were
+ * asleep */
+ goto try_again;
+ }
+
+ /* if we get here, then the user record still hadn't appeared on the
+ * second pass - so we use the candidate record */
+ atomic_set(&candidate->usage, 1);
+ atomic_set(&candidate->nkeys, 0);
+ atomic_set(&candidate->nikeys, 0);
+ candidate->uid = uid;
+ candidate->qnkeys = 0;
+ candidate->qnbytes = 0;
+ spin_lock_init(&candidate->lock);
+ INIT_LIST_HEAD(&candidate->consq);
+
+ rb_link_node(&candidate->node, parent, p);
+ rb_insert_color(&candidate->node, &key_user_tree);
+ spin_unlock(&key_user_lock);
+ user = candidate;
+ goto out;
+
+ /* okay - we found a user record for this UID */
+ found:
+ atomic_inc(&user->usage);
+ spin_unlock(&key_user_lock);
+ if (candidate)
+ kfree(candidate);
+ out:
+ return user;
+
+} /* end key_user_lookup() */
+
+/*****************************************************************************/
+/*
+ * dispose of a user structure
+ */
+void key_user_put(struct key_user *user)
+{
+ if (atomic_dec_and_lock(&user->usage, &key_user_lock)) {
+ rb_erase(&user->node, &key_user_tree);
+ spin_unlock(&key_user_lock);
+
+ kfree(user);
+ }
+
+} /* end key_user_put() */
+
+/*****************************************************************************/
+/*
+ * insert a key with a fixed serial number
+ */
+static void __init __key_insert_serial(struct key *key)
+{
+ struct rb_node *parent, **p;
+ struct key *xkey;
+
+ parent = NULL;
+ p = &key_serial_tree.rb_node;
+
+ while (*p) {
+ parent = *p;
+ xkey = rb_entry(parent, struct key, serial_node);
+
+ if (key->serial < xkey->serial)
+ p = &(*p)->rb_left;
+ else if (key->serial > xkey->serial)
+ p = &(*p)->rb_right;
+ else
+ BUG();
+ }
+
+ /* we've found a suitable hole - arrange for this key to occupy it */
+ rb_link_node(&key->serial_node, parent, p);
+ rb_insert_color(&key->serial_node, &key_serial_tree);
+
+} /* end __key_insert_serial() */
+
+/*****************************************************************************/
+/*
+ * assign a key the next unique serial number
+ * - we work through all the serial numbers between 2 and 2^31-1 in turn and
+ * then wrap
+ */
+static inline void key_alloc_serial(struct key *key)
+{
+ struct rb_node *parent, **p;
+ struct key *xkey;
+
+ spin_lock(&key_serial_lock);
+
+ /* propose a likely serial number and look for a hole for it in the
+ * serial number tree */
+ key->serial = key_serial_next;
+ if (key->serial < 3)
+ key->serial = 3;
+ key_serial_next = key->serial + 1;
+
+ parent = NULL;
+ p = &key_serial_tree.rb_node;
+
+ while (*p) {
+ parent = *p;
+ xkey = rb_entry(parent, struct key, serial_node);
+
+ if (key->serial < xkey->serial)
+ p = &(*p)->rb_left;
+ else if (key->serial > xkey->serial)
+ p = &(*p)->rb_right;
+ else
+ goto serial_exists;
+ }
+ goto insert_here;
+
+ /* we found a key with the proposed serial number - walk the tree from
+ * that point looking for the next unused serial number */
+ serial_exists:
+ for (;;) {
+ key->serial = key_serial_next;
+ if (key->serial < 2)
+ key->serial = 2;
+ key_serial_next = key->serial + 1;
+
+ if (!parent->rb_parent)
+ p = &key_serial_tree.rb_node;
+ else if (parent->rb_parent->rb_left == parent)
+ p = &parent->rb_parent->rb_left;
+ else
+ p = &parent->rb_parent->rb_right;
+
+ parent = rb_next(parent);
+ if (!parent)
+ break;
+
+ xkey = rb_entry(parent, struct key, serial_node);
+ if (key->serial < xkey->serial)
+ goto insert_here;
+ }
+
+ /* we've found a suitable hole - arrange for this key to occupy it */
+ insert_here:
+ rb_link_node(&key->serial_node, parent, p);
+ rb_insert_color(&key->serial_node, &key_serial_tree);
+
+ spin_unlock(&key_serial_lock);
+
+} /* end key_alloc_serial() */
+
+/*****************************************************************************/
+/*
+ * allocate a key of the specified type
+ * - update the user's quota to reflect the existence of the key
+ * - called from a key-type operation with key_types_sem read-locked by either
+ * key_create_or_update() or by key_duplicate(); this prevents unregistration
+ * of the key type
+ * - upon return the key is as yet uninstantiated; the caller needs to either
+ * instantiate the key or discard it before returning
+ */
+struct key *key_alloc(struct key_type *type, const char *desc,
+ uid_t uid, gid_t gid, key_perm_t perm,
+ int not_in_quota)
+{
+ struct key_user *user = NULL;
+ struct key *key;
+ size_t desclen, quotalen;
+
+ key = ERR_PTR(-EINVAL);
+ if (!desc || !*desc)
+ goto error;
+
+ desclen = strlen(desc) + 1;
+ quotalen = desclen + type->def_datalen;
+
+ /* get hold of the key tracking for this user */
+ user = key_user_lookup(uid);
+ if (!user)
+ goto no_memory_1;
+
+ /* check that the user's quota permits allocation of another key and
+ * its description */
+ if (!not_in_quota) {
+ spin_lock(&user->lock);
+ if (user->qnkeys + 1 >= KEYQUOTA_MAX_KEYS &&
+ user->qnbytes + quotalen >= KEYQUOTA_MAX_BYTES
+ )
+ goto no_quota;
+
+ user->qnkeys++;
+ user->qnbytes += quotalen;
+ spin_unlock(&user->lock);
+ }
+
+ /* allocate and initialise the key and its description */
+ key = kmem_cache_alloc(key_jar, SLAB_KERNEL);
+ if (!key)
+ goto no_memory_2;
+
+ if (desc) {
+ key->description = kmalloc(desclen, GFP_KERNEL);
+ if (!key->description)
+ goto no_memory_3;
+
+ memcpy(key->description, desc, desclen);
+ }
+
+ atomic_set(&key->usage, 1);
+ rwlock_init(&key->lock);
+ init_rwsem(&key->sem);
+ key->type = type;
+ key->user = user;
+ key->quotalen = quotalen;
+ key->datalen = type->def_datalen;
+ key->uid = uid;
+ key->gid = gid;
+ key->perm = perm;
+ key->flags = 0;
+ key->expiry = 0;
+ key->payload.data = NULL;
+
+ if (!not_in_quota)
+ key->flags |= KEY_FLAG_IN_QUOTA;
+
+ memset(&key->type_data, 0, sizeof(key->type_data));
+
+#ifdef KEY_DEBUGGING
+ key->magic = KEY_DEBUG_MAGIC;
+#endif
+
+ /* publish the key by giving it a serial number */
+ atomic_inc(&user->nkeys);
+ key_alloc_serial(key);
+
+ error:
+ return key;
+
+ no_memory_3:
+ kmem_cache_free(key_jar, key);
+ no_memory_2:
+ if (!not_in_quota) {
+ spin_lock(&user->lock);
+ user->qnkeys--;
+ user->qnbytes -= quotalen;
+ spin_unlock(&user->lock);
+ }
+ key_user_put(user);
+ no_memory_1:
+ key = ERR_PTR(-ENOMEM);
+ goto error;
+
+ no_quota:
+ spin_unlock(&user->lock);
+ key_user_put(user);
+ key = ERR_PTR(-EDQUOT);
+ goto error;
+
+} /* end key_alloc() */
+
+EXPORT_SYMBOL(key_alloc);
+
+/*****************************************************************************/
+/*
+ * reserve an amount of quota for the key's payload
+ */
+int key_payload_reserve(struct key *key, size_t datalen)
+{
+ int delta = (int) datalen - key->datalen;
+ int ret = 0;
+
+ key_check(key);
+
+ /* contemplate the quota adjustment */
+ if (delta != 0 && key->flags & KEY_FLAG_IN_QUOTA) {
+ spin_lock(&key->user->lock);
+
+ if (delta > 0 &&
+ key->user->qnbytes + delta > KEYQUOTA_MAX_BYTES
+ ) {
+ ret = -EDQUOT;
+ }
+ else {
+ key->user->qnbytes += delta;
+ key->quotalen += delta;
+ }
+ spin_unlock(&key->user->lock);
+ }
+
+ /* change the recorded data length if that didn't generate an error */
+ if (ret == 0)
+ key->datalen = datalen;
+
+ return ret;
+
+} /* end key_payload_reserve() */
+
+EXPORT_SYMBOL(key_payload_reserve);
+
+/*****************************************************************************/
+/*
+ * instantiate a key and link it into the target keyring atomically
+ * - called with the target keyring's semaphore writelocked
+ */
+static int __key_instantiate_and_link(struct key *key,
+ const void *data,
+ size_t datalen,
+ struct key *keyring)
+{
+ int ret, awaken;
+
+ key_check(key);
+ key_check(keyring);
+
+ awaken = 0;
+ ret = -EBUSY;
+
+ down_write(&key_construction_sem);
+
+ /* can't instantiate twice */
+ if (!(key->flags & KEY_FLAG_INSTANTIATED)) {
+ /* instantiate the key */
+ ret = key->type->instantiate(key, data, datalen);
+
+ if (ret == 0) {
+ /* mark the key as being instantiated */
+ write_lock(&key->lock);
+
+ atomic_inc(&key->user->nikeys);
+ key->flags |= KEY_FLAG_INSTANTIATED;
+
+ if (key->flags & KEY_FLAG_USER_CONSTRUCT) {
+ key->flags &= ~KEY_FLAG_USER_CONSTRUCT;
+ awaken = 1;
+ }
+
+ write_unlock(&key->lock);
+
+ /* and link it into the destination keyring */
+ if (keyring)
+ ret = __key_link(keyring, key);
+ }
+ }
+
+ up_write(&key_construction_sem);
+
+ /* wake up anyone waiting for a key to be constructed */
+ if (awaken)
+ wake_up_all(&request_key_conswq);
+
+ return ret;
+
+} /* end __key_instantiate_and_link() */
+
+/*****************************************************************************/
+/*
+ * instantiate a key and link it into the target keyring atomically
+ */
+int key_instantiate_and_link(struct key *key,
+ const void *data,
+ size_t datalen,
+ struct key *keyring)
+{
+ int ret;
+
+ if (keyring)
+ down_write(&keyring->sem);
+
+ ret = __key_instantiate_and_link(key, data, datalen, keyring);
+
+ if (keyring)
+ up_write(&keyring->sem);
+
+ return ret;
+} /* end key_instantiate_and_link() */
+
+EXPORT_SYMBOL(key_instantiate_and_link);
+
+/*****************************************************************************/
+/*
+ * negatively instantiate a key and link it into the target keyring atomically
+ */
+int key_negate_and_link(struct key *key,
+ unsigned timeout,
+ struct key *keyring)
+{
+ struct timespec now;
+ int ret, awaken;
+
+ key_check(key);
+ key_check(keyring);
+
+ awaken = 0;
+ ret = -EBUSY;
+
+ if (keyring)
+ down_write(&keyring->sem);
+
+ down_write(&key_construction_sem);
+
+ /* can't instantiate twice */
+ if (!(key->flags & KEY_FLAG_INSTANTIATED)) {
+ /* mark the key as being negatively instantiated */
+ write_lock(&key->lock);
+
+ atomic_inc(&key->user->nikeys);
+ key->flags |= KEY_FLAG_INSTANTIATED | KEY_FLAG_NEGATIVE;
+ now = current_kernel_time();
+ key->expiry = now.tv_sec + timeout;
+
+ if (key->flags & KEY_FLAG_USER_CONSTRUCT) {
+ key->flags &= ~KEY_FLAG_USER_CONSTRUCT;
+ awaken = 1;
+ }
+
+ write_unlock(&key->lock);
+ ret = 0;
+
+ /* and link it into the destination keyring */
+ if (keyring)
+ ret = __key_link(keyring, key);
+ }
+
+ up_write(&key_construction_sem);
+
+ if (keyring)
+ up_write(&keyring->sem);
+
+ /* wake up anyone waiting for a key to be constructed */
+ if (awaken)
+ wake_up_all(&request_key_conswq);
+
+ return ret;
+
+} /* end key_negate_and_link() */
+
+EXPORT_SYMBOL(key_negate_and_link);
+
+/*****************************************************************************/
+/*
+ * do cleaning up in process context so that we don't have to disable
+ * interrupts all over the place
+ */
+static void key_cleanup(void *data)
+{
+ struct rb_node *_n;
+ struct key *key;
+
+ go_again:
+ /* look for a dead key in the tree */
+ spin_lock(&key_serial_lock);
+
+ for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
+ key = rb_entry(_n, struct key, serial_node);
+
+ if (atomic_read(&key->usage) == 0)
+ goto found_dead_key;
+ }
+
+ spin_unlock(&key_serial_lock);
+ return;
+
+ found_dead_key:
+ /* we found a dead key - once we've removed it from the tree, we can
+ * drop the lock */
+ rb_erase(&key->serial_node, &key_serial_tree);
+ spin_unlock(&key_serial_lock);
+
+ /* deal with the user's key tracking and quota */
+ if (key->flags & KEY_FLAG_IN_QUOTA) {
+ spin_lock(&key->user->lock);
+ key->user->qnkeys--;
+ key->user->qnbytes -= key->quotalen;
+ spin_unlock(&key->user->lock);
+ }
+
+ atomic_dec(&key->user->nkeys);
+ if (key->flags & KEY_FLAG_INSTANTIATED)
+ atomic_dec(&key->user->nikeys);
+
+ key_user_put(key->user);
+
+ /* now throw away the key memory */
+ if (key->type->destroy)
+ key->type->destroy(key);
+
+ kfree(key->description);
+
+#ifdef KEY_DEBUGGING
+ key->magic = KEY_DEBUG_MAGIC_X;
+#endif
+ kmem_cache_free(key_jar, key);
+
+ /* there may, of course, be more than one key to destroy */
+ goto go_again;
+
+} /* end key_cleanup() */
+
+/*****************************************************************************/
+/*
+ * dispose of a reference to a key
+ * - when all the references are gone, we schedule the cleanup task to come and
+ * pull it out of the tree in definite process context
+ */
+void key_put(struct key *key)
+{
+ if (key) {
+ key_check(key);
+
+ if (atomic_dec_and_test(&key->usage))
+ schedule_work(&key_cleanup_task);
+ }
+
+} /* end key_put() */
+
+EXPORT_SYMBOL(key_put);
+
+/*****************************************************************************/
+/*
+ * find a key by its serial number
+ */
+struct key *key_lookup(key_serial_t id)
+{
+ struct rb_node *n;
+ struct key *key;
+
+ spin_lock(&key_serial_lock);
+
+ /* search the tree for the specified key */
+ n = key_serial_tree.rb_node;
+ while (n) {
+ key = rb_entry(n, struct key, serial_node);
+
+ if (id < key->serial)
+ n = n->rb_left;
+ else if (id > key->serial)
+ n = n->rb_right;
+ else
+ goto found;
+ }
+
+ spin_unlock(&key_serial_lock);
+
+ not_found:
+ key = ERR_PTR(-ENOKEY);
+ goto error;
+
+ found:
+ /* pretent doesn't exist if it's dead */
+ if (atomic_read(&key->usage) == 0 ||
+ (key->flags & KEY_FLAG_DEAD) ||
+ key->type == &key_type_dead)
+ goto not_found;
+
+ /* this races with key_put(), but that doesn't matter since key_put()
+ * doesn't actually change the key
+ */
+ atomic_inc(&key->usage);
+
+ spin_unlock(&key_serial_lock);
+ error:
+ return key;
+
+} /* end key_lookup() */
+
+/*****************************************************************************/
+/*
+ * find and lock the specified key type against removal
+ * - we return with the sem readlocked
+ */
+struct key_type *key_type_lookup(const char *type)
+{
+ struct key_type *ktype;
+
+ down_read(&key_types_sem);
+
+ /* look up the key type to see if it's one of the registered kernel
+ * types */
+ list_for_each_entry(ktype, &key_types_list, link) {
+ if (strcmp(ktype->name, type) == 0)
+ goto found_kernel_type;
+ }
+
+ up_read(&key_types_sem);
+ ktype = ERR_PTR(-ENOKEY);
+
+ found_kernel_type:
+ return ktype;
+
+} /* end key_type_lookup() */
+
+/*****************************************************************************/
+/*
+ * unlock a key type
+ */
+void key_type_put(struct key_type *ktype)
+{
+ up_read(&key_types_sem);
+
+} /* end key_type_put() */
+
+/*****************************************************************************/
+/*
+ * attempt to update an existing key
+ * - the key has an incremented refcount
+ * - we need to put the key if we get an error
+ */
+static inline struct key *__key_update(struct key *key, const void *payload,
+ size_t plen)
+{
+ int ret;
+
+ /* need write permission on the key to update it */
+ ret = -EACCES;
+ if (!key_permission(key, KEY_WRITE))
+ goto error;
+
+ ret = -EEXIST;
+ if (!key->type->update)
+ goto error;
+
+ down_write(&key->sem);
+
+ ret = key->type->update(key, payload, plen);
+
+ if (ret == 0) {
+ /* updating a negative key instantiates it */
+ write_lock(&key->lock);
+ key->flags &= ~KEY_FLAG_NEGATIVE;
+ write_unlock(&key->lock);
+ }
+
+ up_write(&key->sem);
+
+ if (ret < 0)
+ goto error;
+ out:
+ return key;
+
+ error:
+ key_put(key);
+ key = ERR_PTR(ret);
+ goto out;
+
+} /* end __key_update() */
+
+/*****************************************************************************/
+/*
+ * search the specified keyring for a key of the same description; if one is
+ * found, update it, otherwise add a new one
+ */
+struct key *key_create_or_update(struct key *keyring,
+ const char *type,
+ const char *description,
+ const void *payload,
+ size_t plen,
+ int not_in_quota)
+{
+ struct key_type *ktype;
+ struct key *key = NULL;
+ key_perm_t perm;
+ int ret;
+
+ key_check(keyring);
+
+ /* look up the key type to see if it's one of the registered kernel
+ * types */
+ ktype = key_type_lookup(type);
+ if (IS_ERR(ktype)) {
+ key = ERR_PTR(-ENODEV);
+ goto error;
+ }
+
+ ret = -EINVAL;
+ if (!ktype->match || !ktype->instantiate)
+ goto error_2;
+
+ /* search for an existing key of the same type and description in the
+ * destination keyring
+ */
+ down_write(&keyring->sem);
+
+ key = __keyring_search_one(keyring, ktype, description, 0);
+ if (!IS_ERR(key))
+ goto found_matching_key;
+
+ /* if we're going to allocate a new key, we're going to have to modify
+ * the keyring */
+ ret = -EACCES;
+ if (!key_permission(keyring, KEY_WRITE))
+ goto error_3;
+
+ /* decide on the permissions we want */
+ perm = KEY_USR_VIEW | KEY_USR_SEARCH | KEY_USR_LINK;
+
+ if (ktype->read)
+ perm |= KEY_USR_READ;
+
+ if (ktype == &key_type_keyring || ktype->update)
+ perm |= KEY_USR_WRITE;
+
+ /* allocate a new key */
+ key = key_alloc(ktype, description, current->fsuid, current->fsgid,
+ perm, not_in_quota);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error_3;
+ }
+
+ /* instantiate it and link it into the target keyring */
+ ret = __key_instantiate_and_link(key, payload, plen, keyring);
+ if (ret < 0) {
+ key_put(key);
+ key = ERR_PTR(ret);
+ }
+
+ error_3:
+ up_write(&keyring->sem);
+ error_2:
+ key_type_put(ktype);
+ error:
+ return key;
+
+ found_matching_key:
+ /* we found a matching key, so we're going to try to update it
+ * - we can drop the locks first as we have the key pinned
+ */
+ up_write(&keyring->sem);
+ key_type_put(ktype);
+
+ key = __key_update(key, payload, plen);
+ goto error;
+
+} /* end key_create_or_update() */
+
+EXPORT_SYMBOL(key_create_or_update);
+
+/*****************************************************************************/
+/*
+ * update a key
+ */
+int key_update(struct key *key, const void *payload, size_t plen)
+{
+ int ret;
+
+ key_check(key);
+
+ /* the key must be writable */
+ ret = -EACCES;
+ if (!key_permission(key, KEY_WRITE))
+ goto error;
+
+ /* attempt to update it if supported */
+ ret = -EOPNOTSUPP;
+ if (key->type->update) {
+ down_write(&key->sem);
+ ret = key->type->update(key, payload, plen);
+
+ if (ret == 0) {
+ /* updating a negative key instantiates it */
+ write_lock(&key->lock);
+ key->flags &= ~KEY_FLAG_NEGATIVE;
+ write_unlock(&key->lock);
+ }
+
+ up_write(&key->sem);
+ }
+
+ error:
+ return ret;
+
+} /* end key_update() */
+
+EXPORT_SYMBOL(key_update);
+
+/*****************************************************************************/
+/*
+ * duplicate a key, potentially with a revised description
+ * - must be supported by the keytype (keyrings for instance can be duplicated)
+ */
+struct key *key_duplicate(struct key *source, const char *desc)
+{
+ struct key *key;
+ int ret;
+
+ key_check(source);
+
+ if (!desc)
+ desc = source->description;
+
+ down_read(&key_types_sem);
+
+ ret = -EINVAL;
+ if (!source->type->duplicate)
+ goto error;
+
+ /* allocate and instantiate a key */
+ key = key_alloc(source->type, desc, current->fsuid, current->fsgid,
+ source->perm, 0);
+ if (IS_ERR(key))
+ goto error_k;
+
+ down_read(&source->sem);
+ ret = key->type->duplicate(key, source);
+ up_read(&source->sem);
+ if (ret < 0)
+ goto error2;
+
+ atomic_inc(&key->user->nikeys);
+
+ write_lock(&key->lock);
+ key->flags |= KEY_FLAG_INSTANTIATED;
+ write_unlock(&key->lock);
+
+ error_k:
+ up_read(&key_types_sem);
+ out:
+ return key;
+
+ error2:
+ key_put(key);
+ error:
+ up_read(&key_types_sem);
+ key = ERR_PTR(ret);
+ goto out;
+
+} /* end key_duplicate() */
+
+/*****************************************************************************/
+/*
+ * revoke a key
+ */
+void key_revoke(struct key *key)
+{
+ key_check(key);
+
+ /* make sure no one's trying to change or use the key when we mark
+ * it */
+ down_write(&key->sem);
+ write_lock(&key->lock);
+ key->flags |= KEY_FLAG_REVOKED;
+ write_unlock(&key->lock);
+ up_write(&key->sem);
+
+} /* end key_revoke() */
+
+EXPORT_SYMBOL(key_revoke);
+
+/*****************************************************************************/
+/*
+ * register a type of key
+ */
+int register_key_type(struct key_type *ktype)
+{
+ struct key_type *p;
+ int ret;
+
+ ret = -EEXIST;
+ down_write(&key_types_sem);
+
+ /* disallow key types with the same name */
+ list_for_each_entry(p, &key_types_list, link) {
+ if (strcmp(p->name, ktype->name) == 0)
+ goto out;
+ }
+
+ /* store the type */
+ list_add(&ktype->link, &key_types_list);
+ ret = 0;
+
+ out:
+ up_write(&key_types_sem);
+ return ret;
+
+} /* end register_key_type() */
+
+EXPORT_SYMBOL(register_key_type);
+
+/*****************************************************************************/
+/*
+ * unregister a type of key
+ */
+void unregister_key_type(struct key_type *ktype)
+{
+ struct rb_node *_n;
+ struct key *key;
+
+ down_write(&key_types_sem);
+
+ /* withdraw the key type */
+ list_del_init(&ktype->link);
+
+ /* need to withdraw all keys of this type */
+ spin_lock(&key_serial_lock);
+
+ for (_n = rb_first(&key_serial_tree); _n; _n = rb_next(_n)) {
+ key = rb_entry(_n, struct key, serial_node);
+
+ if (key->type != ktype)
+ continue;
+
+ write_lock(&key->lock);
+ key->type = &key_type_dead;
+ write_unlock(&key->lock);
+
+ /* there shouldn't be anyone looking at the description or
+ * payload now */
+ if (ktype->destroy)
+ ktype->destroy(key);
+ memset(&key->payload, 0xbd, sizeof(key->payload));
+ }
+
+ spin_unlock(&key_serial_lock);
+ up_write(&key_types_sem);
+
+} /* end unregister_key_type() */
+
+EXPORT_SYMBOL(unregister_key_type);
+
+/*****************************************************************************/
+/*
+ * initialise the key management stuff
+ */
+static int __init key_init(void)
+{
+ /* allocate a slab in which we can store keys */
+ key_jar = kmem_cache_create("key_jar", sizeof(struct key),
+ 0, SLAB_HWCACHE_ALIGN, NULL, NULL);
+ if (!key_jar)
+ panic("Cannot create key jar\n");
+
+ /* add the special key types */
+ list_add_tail(&key_type_keyring.link, &key_types_list);
+ list_add_tail(&key_type_dead.link, &key_types_list);
+ list_add_tail(&key_type_user.link, &key_types_list);
+
+ /* record the root user tracking */
+ rb_link_node(&root_key_user.node,
+ NULL,
+ &key_user_tree.rb_node);
+
+ rb_insert_color(&root_key_user.node,
+ &key_user_tree);
+
+ /* record root's user standard keyrings */
+ key_check(&root_user_keyring);
+ key_check(&root_session_keyring);
+
+ __key_insert_serial(&root_user_keyring);
+ __key_insert_serial(&root_session_keyring);
+
+ keyring_publish_name(&root_user_keyring);
+ keyring_publish_name(&root_session_keyring);
+
+ /* link the two root keyrings together */
+ key_link(&root_session_keyring, &root_user_keyring);
+
+ return 0;
+
+} /* end key_init() */
+
+subsys_initcall(key_init);
--- /dev/null
+/* keyctl.c: userspace keyctl operations
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/keyctl.h>
+#include <linux/fs.h>
+#include <linux/err.h>
+#include <asm/uaccess.h>
+#include "internal.h"
+
+/*****************************************************************************/
+/*
+ * extract the description of a new key from userspace and either add it as a
+ * new key to the specified keyring or update a matching key in that keyring
+ * - the keyring must be writable
+ * - returns the new key's serial number
+ * - implements add_key()
+ */
+asmlinkage long sys_add_key(const char __user *_type,
+ const char __user *_description,
+ const void __user *_payload,
+ size_t plen,
+ key_serial_t ringid)
+{
+ struct key *keyring, *key;
+ char type[32], *description;
+ void *payload;
+ long dlen, ret;
+
+ ret = -EINVAL;
+ if (plen > 32767)
+ goto error;
+
+ /* draw all the data into kernel space */
+ ret = strncpy_from_user(type, _type, sizeof(type) - 1);
+ if (ret < 0)
+ goto error;
+ type[31] = '\0';
+
+ ret = -EFAULT;
+ dlen = strnlen_user(_description, PAGE_SIZE - 1);
+ if (dlen <= 0)
+ goto error;
+
+ ret = -EINVAL;
+ if (dlen > PAGE_SIZE - 1)
+ goto error;
+
+ ret = -ENOMEM;
+ description = kmalloc(dlen + 1, GFP_KERNEL);
+ if (!description)
+ goto error;
+
+ ret = -EFAULT;
+ if (copy_from_user(description, _description, dlen + 1) != 0)
+ goto error2;
+
+ /* pull the payload in if one was supplied */
+ payload = NULL;
+
+ if (_payload) {
+ ret = -ENOMEM;
+ payload = kmalloc(plen, GFP_KERNEL);
+ if (!payload)
+ goto error2;
+
+ ret = -EFAULT;
+ if (copy_from_user(payload, _payload, plen) != 0)
+ goto error3;
+ }
+
+ /* find the target keyring (which must be writable) */
+ keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+ if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto error3;
+ }
+
+ /* create or update the requested key and add it to the target
+ * keyring */
+ key = key_create_or_update(keyring, type, description,
+ payload, plen, 0);
+ if (!IS_ERR(key)) {
+ ret = key->serial;
+ key_put(key);
+ }
+ else {
+ ret = PTR_ERR(key);
+ }
+
+ key_put(keyring);
+ error3:
+ kfree(payload);
+ error2:
+ kfree(description);
+ error:
+ return ret;
+
+} /* end sys_add_key() */
+
+/*****************************************************************************/
+/*
+ * search the process keyrings for a matching key
+ * - nested keyrings may also be searched if they have Search permission
+ * - if a key is found, it will be attached to the destination keyring if
+ * there's one specified
+ * - /sbin/request-key will be invoked if _callout_info is non-NULL
+ * - the _callout_info string will be passed to /sbin/request-key
+ * - if the _callout_info string is empty, it will be rendered as "-"
+ * - implements request_key()
+ */
+asmlinkage long sys_request_key(const char __user *_type,
+ const char __user *_description,
+ const char __user *_callout_info,
+ key_serial_t destringid)
+{
+ struct key_type *ktype;
+ struct key *key, *dest;
+ char type[32], *description, *callout_info;
+ long dlen, ret;
+
+ /* pull the type into kernel space */
+ ret = strncpy_from_user(type, _type, sizeof(type) - 1);
+ if (ret < 0)
+ goto error;
+ type[31] = '\0';
+
+ /* pull the description into kernel space */
+ ret = -EFAULT;
+ dlen = strnlen_user(_description, PAGE_SIZE - 1);
+ if (dlen <= 0)
+ goto error;
+
+ ret = -EINVAL;
+ if (dlen > PAGE_SIZE - 1)
+ goto error;
+
+ ret = -ENOMEM;
+ description = kmalloc(dlen + 1, GFP_KERNEL);
+ if (!description)
+ goto error;
+
+ ret = -EFAULT;
+ if (copy_from_user(description, _description, dlen + 1) != 0)
+ goto error2;
+
+ /* pull the callout info into kernel space */
+ callout_info = NULL;
+ if (_callout_info) {
+ ret = -EFAULT;
+ dlen = strnlen_user(_callout_info, PAGE_SIZE - 1);
+ if (dlen <= 0)
+ goto error2;
+
+ ret = -EINVAL;
+ if (dlen > PAGE_SIZE - 1)
+ goto error2;
+
+ ret = -ENOMEM;
+ callout_info = kmalloc(dlen + 1, GFP_KERNEL);
+ if (!callout_info)
+ goto error2;
+
+ ret = -EFAULT;
+ if (copy_from_user(callout_info, _callout_info, dlen + 1) != 0)
+ goto error3;
+ }
+
+ /* get the destination keyring if specified */
+ dest = NULL;
+ if (destringid) {
+ dest = lookup_user_key(destringid, 1, 0, KEY_WRITE);
+ if (IS_ERR(dest)) {
+ ret = PTR_ERR(dest);
+ goto error3;
+ }
+ }
+
+ /* find the key type */
+ ktype = key_type_lookup(type);
+ if (IS_ERR(ktype)) {
+ ret = PTR_ERR(ktype);
+ goto error4;
+ }
+
+ /* do the search */
+ key = request_key(ktype, description, callout_info);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error5;
+ }
+
+ /* link the resulting key to the destination keyring */
+ if (dest) {
+ ret = key_link(dest, key);
+ if (ret < 0)
+ goto error6;
+ }
+
+ ret = key->serial;
+
+ error6:
+ key_put(key);
+ error5:
+ key_type_put(ktype);
+ error4:
+ key_put(dest);
+ error3:
+ kfree(callout_info);
+ error2:
+ kfree(description);
+ error:
+ return ret;
+
+} /* end sys_request_key() */
+
+/*****************************************************************************/
+/*
+ * get the ID of the specified process keyring
+ * - the keyring must have search permission to be found
+ * - implements keyctl(KEYCTL_GET_KEYRING_ID)
+ */
+static long keyctl_get_keyring_ID(key_serial_t id, int create)
+{
+ struct key *key;
+ long ret;
+
+ key = lookup_user_key(id, create, 0, KEY_SEARCH);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error;
+ }
+
+ ret = key->serial;
+ key_put(key);
+ error:
+ return ret;
+
+} /* end keyctl_get_keyring_ID() */
+
+/*****************************************************************************/
+/*
+ * join the session keyring
+ * - implements keyctl(KEYCTL_JOIN_SESSION_KEYRING)
+ */
+static long keyctl_join_session_keyring(const char __user *_name)
+{
+ char *name;
+ long nlen, ret;
+
+ /* fetch the name from userspace */
+ name = NULL;
+ if (_name) {
+ ret = -EFAULT;
+ nlen = strnlen_user(_name, PAGE_SIZE - 1);
+ if (nlen <= 0)
+ goto error;
+
+ ret = -EINVAL;
+ if (nlen > PAGE_SIZE - 1)
+ goto error;
+
+ ret = -ENOMEM;
+ name = kmalloc(nlen + 1, GFP_KERNEL);
+ if (!name)
+ goto error;
+
+ ret = -EFAULT;
+ if (copy_from_user(name, _name, nlen + 1) != 0)
+ goto error2;
+ }
+
+ /* join the session */
+ ret = join_session_keyring(name);
+
+ error2:
+ kfree(name);
+ error:
+ return ret;
+
+} /* end keyctl_join_session_keyring() */
+
+/*****************************************************************************/
+/*
+ * update a key's data payload
+ * - the key must be writable
+ * - implements keyctl(KEYCTL_UPDATE)
+ */
+static long keyctl_update_key(key_serial_t id,
+ const void __user *_payload,
+ size_t plen)
+{
+ struct key *key;
+ void *payload;
+ long ret;
+
+ ret = -EINVAL;
+ if (plen > PAGE_SIZE)
+ goto error;
+
+ /* pull the payload in if one was supplied */
+ payload = NULL;
+ if (_payload) {
+ ret = -ENOMEM;
+ payload = kmalloc(plen, GFP_KERNEL);
+ if (!payload)
+ goto error;
+
+ ret = -EFAULT;
+ if (copy_from_user(payload, _payload, plen) != 0)
+ goto error2;
+ }
+
+ /* find the target key (which must be writable) */
+ key = lookup_user_key(id, 0, 0, KEY_WRITE);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error2;
+ }
+
+ /* update the key */
+ ret = key_update(key, payload, plen);
+
+ key_put(key);
+ error2:
+ kfree(payload);
+ error:
+ return ret;
+
+} /* end keyctl_update_key() */
+
+/*****************************************************************************/
+/*
+ * revoke a key
+ * - the key must be writable
+ * - implements keyctl(KEYCTL_REVOKE)
+ */
+static long keyctl_revoke_key(key_serial_t id)
+{
+ struct key *key;
+ long ret;
+
+ key = lookup_user_key(id, 0, 0, KEY_WRITE);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error;
+ }
+
+ key_revoke(key);
+ ret = 0;
+
+ key_put(key);
+ error:
+ return 0;
+
+} /* end keyctl_revoke_key() */
+
+/*****************************************************************************/
+/*
+ * clear the specified process keyring
+ * - the keyring must be writable
+ * - implements keyctl(KEYCTL_CLEAR)
+ */
+static long keyctl_keyring_clear(key_serial_t ringid)
+{
+ struct key *keyring;
+ long ret;
+
+ keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+ if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto error;
+ }
+
+ ret = keyring_clear(keyring);
+
+ key_put(keyring);
+ error:
+ return ret;
+
+} /* end keyctl_keyring_clear() */
+
+/*****************************************************************************/
+/*
+ * link a key into a keyring
+ * - the keyring must be writable
+ * - the key must be linkable
+ * - implements keyctl(KEYCTL_LINK)
+ */
+static long keyctl_keyring_link(key_serial_t id, key_serial_t ringid)
+{
+ struct key *keyring, *key;
+ long ret;
+
+ keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+ if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto error;
+ }
+
+ key = lookup_user_key(id, 1, 0, KEY_LINK);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error2;
+ }
+
+ ret = key_link(keyring, key);
+
+ key_put(key);
+ error2:
+ key_put(keyring);
+ error:
+ return ret;
+
+} /* end keyctl_keyring_link() */
+
+/*****************************************************************************/
+/*
+ * unlink the first attachment of a key from a keyring
+ * - the keyring must be writable
+ * - we don't need any permissions on the key
+ * - implements keyctl(KEYCTL_UNLINK)
+ */
+static long keyctl_keyring_unlink(key_serial_t id, key_serial_t ringid)
+{
+ struct key *keyring, *key;
+ long ret;
+
+ keyring = lookup_user_key(ringid, 0, 0, KEY_WRITE);
+ if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto error;
+ }
+
+ key = lookup_user_key(id, 0, 0, 0);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error2;
+ }
+
+ ret = key_unlink(keyring, key);
+
+ key_put(key);
+ error2:
+ key_put(keyring);
+ error:
+ return ret;
+
+} /* end keyctl_keyring_unlink() */
+
+/*****************************************************************************/
+/*
+ * describe a user key
+ * - the key must have view permission
+ * - if there's a buffer, we place up to buflen bytes of data into it
+ * - unless there's an error, we return the amount of description available,
+ * irrespective of how much we may have copied
+ * - the description is formatted thus:
+ * type;uid;gid;perm;description<NUL>
+ * - implements keyctl(KEYCTL_DESCRIBE)
+ */
+static long keyctl_describe_key(key_serial_t keyid,
+ char __user *buffer,
+ size_t buflen)
+{
+ struct key *key;
+ char *tmpbuf;
+ long ret;
+
+ key = lookup_user_key(keyid, 0, 1, KEY_VIEW);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error;
+ }
+
+ /* calculate how much description we're going to return */
+ ret = -ENOMEM;
+ tmpbuf = kmalloc(PAGE_SIZE, GFP_KERNEL);
+ if (!tmpbuf)
+ goto error2;
+
+ ret = snprintf(tmpbuf, PAGE_SIZE - 1,
+ "%s;%d;%d;%06x;%s",
+ key->type->name,
+ key->uid,
+ key->gid,
+ key->perm,
+ key->description ? key->description :""
+ );
+
+ /* include a NUL char at the end of the data */
+ if (ret > PAGE_SIZE - 1)
+ ret = PAGE_SIZE - 1;
+ tmpbuf[ret] = 0;
+ ret++;
+
+ /* consider returning the data */
+ if (buffer && buflen > 0) {
+ if (buflen > ret)
+ buflen = ret;
+
+ if (copy_to_user(buffer, tmpbuf, buflen) != 0)
+ ret = -EFAULT;
+ }
+
+ kfree(tmpbuf);
+ error2:
+ key_put(key);
+ error:
+ return ret;
+
+} /* end keyctl_describe_key() */
+
+/*****************************************************************************/
+/*
+ * search the specified keyring for a matching key
+ * - the start keyring must be searchable
+ * - nested keyrings may also be searched if they are searchable
+ * - only keys with search permission may be found
+ * - if a key is found, it will be attached to the destination keyring if
+ * there's one specified
+ * - implements keyctl(KEYCTL_SEARCH)
+ */
+static long keyctl_keyring_search(key_serial_t ringid,
+ const char __user *_type,
+ const char __user *_description,
+ key_serial_t destringid)
+{
+ struct key_type *ktype;
+ struct key *keyring, *key, *dest;
+ char type[32], *description;
+ long dlen, ret;
+
+ /* pull the type and description into kernel space */
+ ret = strncpy_from_user(type, _type, sizeof(type) - 1);
+ if (ret < 0)
+ goto error;
+ type[31] = '\0';
+
+ ret = -EFAULT;
+ dlen = strnlen_user(_description, PAGE_SIZE - 1);
+ if (dlen <= 0)
+ goto error;
+
+ ret = -EINVAL;
+ if (dlen > PAGE_SIZE - 1)
+ goto error;
+
+ ret = -ENOMEM;
+ description = kmalloc(dlen + 1, GFP_KERNEL);
+ if (!description)
+ goto error;
+
+ ret = -EFAULT;
+ if (copy_from_user(description, _description, dlen + 1) != 0)
+ goto error2;
+
+ /* get the keyring at which to begin the search */
+ keyring = lookup_user_key(ringid, 0, 0, KEY_SEARCH);
+ if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto error2;
+ }
+
+ /* get the destination keyring if specified */
+ dest = NULL;
+ if (destringid) {
+ dest = lookup_user_key(destringid, 1, 0, KEY_WRITE);
+ if (IS_ERR(dest)) {
+ ret = PTR_ERR(dest);
+ goto error3;
+ }
+ }
+
+ /* find the key type */
+ ktype = key_type_lookup(type);
+ if (IS_ERR(ktype)) {
+ ret = PTR_ERR(ktype);
+ goto error4;
+ }
+
+ /* do the search */
+ key = keyring_search(keyring, ktype, description);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+
+ /* treat lack or presence of a negative key the same */
+ if (ret == -EAGAIN)
+ ret = -ENOKEY;
+ goto error5;
+ }
+
+ /* link the resulting key to the destination keyring if we can */
+ if (dest) {
+ ret = -EACCES;
+ if (!key_permission(key, KEY_LINK))
+ goto error6;
+
+ ret = key_link(dest, key);
+ if (ret < 0)
+ goto error6;
+ }
+
+ ret = key->serial;
+
+ error6:
+ key_put(key);
+ error5:
+ key_type_put(ktype);
+ error4:
+ key_put(dest);
+ error3:
+ key_put(keyring);
+ error2:
+ kfree(description);
+ error:
+ return ret;
+
+} /* end keyctl_keyring_search() */
+
+/*****************************************************************************/
+/*
+ * see if the key we're looking at is the target key
+ */
+static int keyctl_read_key_same(const struct key *key, const void *target)
+{
+ return key == target;
+
+} /* end keyctl_read_key_same() */
+
+/*****************************************************************************/
+/*
+ * read a user key's payload
+ * - the keyring must be readable or the key must be searchable from the
+ * process's keyrings
+ * - if there's a buffer, we place up to buflen bytes of data into it
+ * - unless there's an error, we return the amount of data in the key,
+ * irrespective of how much we may have copied
+ * - implements keyctl(KEYCTL_READ)
+ */
+static long keyctl_read_key(key_serial_t keyid,
+ char __user *buffer,
+ size_t buflen)
+{
+ struct key *key, *skey;
+ long ret;
+
+ /* find the key first */
+ key = lookup_user_key(keyid, 0, 0, 0);
+ if (!IS_ERR(key)) {
+ /* see if we can read it directly */
+ if (key_permission(key, KEY_READ))
+ goto can_read_key;
+
+ /* can't; see if it's searchable from this process's
+ * keyrings */
+ ret = -ENOKEY;
+ if (key_permission(key, KEY_SEARCH)) {
+ /* okay - we do have search permission on the key
+ * itself, but do we have the key? */
+ skey = search_process_keyrings_aux(key->type, key,
+ keyctl_read_key_same);
+ if (!IS_ERR(skey))
+ goto can_read_key2;
+ }
+
+ goto error2;
+ }
+
+ ret = -ENOKEY;
+ goto error;
+
+ /* the key is probably readable - now try to read it */
+ can_read_key2:
+ key_put(skey);
+ can_read_key:
+ ret = key_validate(key);
+ if (ret == 0) {
+ ret = -EOPNOTSUPP;
+ if (key->type->read) {
+ /* read the data with the semaphore held (since we
+ * might sleep) */
+ down_read(&key->sem);
+ ret = key->type->read(key, buffer, buflen);
+ up_read(&key->sem);
+ }
+ }
+
+ error2:
+ key_put(key);
+ error:
+ return ret;
+
+} /* end keyctl_read_key() */
+
+/*****************************************************************************/
+/*
+ * change the ownership of a key
+ * - the keyring owned by the changer
+ * - if the uid or gid is -1, then that parameter is not changed
+ * - implements keyctl(KEYCTL_CHOWN)
+ */
+static long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
+{
+ struct key *key;
+ long ret;
+
+ ret = 0;
+ if (uid == (uid_t) -1 && gid == (gid_t) -1)
+ goto error;
+
+ key = lookup_user_key(id, 1, 1, 0);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error;
+ }
+
+ /* make the changes with the locks held to prevent chown/chown races */
+ ret = -EACCES;
+ down_write(&key->sem);
+ write_lock(&key->lock);
+
+ if (!capable(CAP_SYS_ADMIN)) {
+ /* only the sysadmin can chown a key to some other UID */
+ if (uid != (uid_t) -1 && key->uid != uid)
+ goto no_access;
+
+ /* only the sysadmin can set the key's GID to a group other
+ * than one of those that the current process subscribes to */
+ if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
+ goto no_access;
+ }
+
+ /* change the UID (have to update the quotas) */
+ if (uid != (uid_t) -1 && uid != key->uid) {
+ /* don't support UID changing yet */
+ ret = -EOPNOTSUPP;
+ goto no_access;
+ }
+
+ /* change the GID */
+ if (gid != (gid_t) -1)
+ key->gid = gid;
+
+ ret = 0;
+
+ no_access:
+ write_unlock(&key->lock);
+ up_write(&key->sem);
+ key_put(key);
+ error:
+ return ret;
+
+} /* end keyctl_chown_key() */
+
+/*****************************************************************************/
+/*
+ * change the permission mask on a key
+ * - the keyring owned by the changer
+ * - implements keyctl(KEYCTL_SETPERM)
+ */
+static long keyctl_setperm_key(key_serial_t id, key_perm_t perm)
+{
+ struct key *key;
+ long ret;
+
+ ret = -EINVAL;
+ if (perm & ~(KEY_USR_ALL | KEY_GRP_ALL | KEY_OTH_ALL))
+ goto error;
+
+ key = lookup_user_key(id, 1, 1, 0);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error;
+ }
+
+ /* make the changes with the locks held to prevent chown/chmod
+ * races */
+ ret = -EACCES;
+ down_write(&key->sem);
+ write_lock(&key->lock);
+
+ /* if we're not the sysadmin, we can only chmod a key that we
+ * own */
+ if (!capable(CAP_SYS_ADMIN) && key->uid != current->fsuid)
+ goto no_access;
+
+ /* changing the permissions mask */
+ key->perm = perm;
+ ret = 0;
+
+ no_access:
+ write_unlock(&key->lock);
+ up_write(&key->sem);
+ key_put(key);
+ error:
+ return ret;
+
+} /* end keyctl_setperm_key() */
+
+/*****************************************************************************/
+/*
+ * instantiate the key with the specified payload, and, if one is given, link
+ * the key into the keyring
+ */
+static long keyctl_instantiate_key(key_serial_t id,
+ const void __user *_payload,
+ size_t plen,
+ key_serial_t ringid)
+{
+ struct key *key, *keyring;
+ void *payload;
+ long ret;
+
+ ret = -EINVAL;
+ if (plen > 32767)
+ goto error;
+
+ /* pull the payload in if one was supplied */
+ payload = NULL;
+
+ if (_payload) {
+ ret = -ENOMEM;
+ payload = kmalloc(plen, GFP_KERNEL);
+ if (!payload)
+ goto error;
+
+ ret = -EFAULT;
+ if (copy_from_user(payload, _payload, plen) != 0)
+ goto error2;
+ }
+
+ /* find the target key (which must be writable) */
+ key = lookup_user_key(id, 0, 1, KEY_WRITE);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error2;
+ }
+
+ /* find the destination keyring if present (which must also be
+ * writable) */
+ keyring = NULL;
+ if (ringid) {
+ keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+ if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto error3;
+ }
+ }
+
+ /* instantiate the key and link it into a keyring */
+ ret = key_instantiate_and_link(key, payload, plen, keyring);
+
+ key_put(keyring);
+ error3:
+ key_put(key);
+ error2:
+ kfree(payload);
+ error:
+ return ret;
+
+} /* end keyctl_instantiate_key() */
+
+/*****************************************************************************/
+/*
+ * negatively instantiate the key with the given timeout (in seconds), and, if
+ * one is given, link the key into the keyring
+ */
+static long keyctl_negate_key(key_serial_t id,
+ unsigned timeout,
+ key_serial_t ringid)
+{
+ struct key *key, *keyring;
+ long ret;
+
+ /* find the target key (which must be writable) */
+ key = lookup_user_key(id, 0, 1, KEY_WRITE);
+ if (IS_ERR(key)) {
+ ret = PTR_ERR(key);
+ goto error;
+ }
+
+ /* find the destination keyring if present (which must also be
+ * writable) */
+ keyring = NULL;
+ if (ringid) {
+ keyring = lookup_user_key(ringid, 1, 0, KEY_WRITE);
+ if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto error2;
+ }
+ }
+
+ /* instantiate the key and link it into a keyring */
+ ret = key_negate_and_link(key, timeout, keyring);
+
+ key_put(keyring);
+ error2:
+ key_put(key);
+ error:
+ return ret;
+
+} /* end keyctl_negate_key() */
+
+/*****************************************************************************/
+/*
+ * the key control system call
+ * - currently invoked through prctl()
+ */
+asmlinkage long sys_keyctl(int option, unsigned long arg2, unsigned long arg3,
+ unsigned long arg4, unsigned long arg5)
+{
+ switch (option) {
+ case KEYCTL_GET_KEYRING_ID:
+ return keyctl_get_keyring_ID((key_serial_t) arg2,
+ (int) arg3);
+
+ case KEYCTL_JOIN_SESSION_KEYRING:
+ return keyctl_join_session_keyring((const char __user *) arg3);
+
+ case KEYCTL_UPDATE:
+ return keyctl_update_key((key_serial_t) arg2,
+ (const void __user *) arg3,
+ (size_t) arg4);
+
+ case KEYCTL_REVOKE:
+ return keyctl_revoke_key((key_serial_t) arg2);
+
+ case KEYCTL_DESCRIBE:
+ return keyctl_describe_key((key_serial_t) arg2,
+ (char __user *) arg3,
+ (unsigned) arg4);
+
+ case KEYCTL_CLEAR:
+ return keyctl_keyring_clear((key_serial_t) arg2);
+
+ case KEYCTL_LINK:
+ return keyctl_keyring_link((key_serial_t) arg2,
+ (key_serial_t) arg3);
+
+ case KEYCTL_UNLINK:
+ return keyctl_keyring_unlink((key_serial_t) arg2,
+ (key_serial_t) arg3);
+
+ case KEYCTL_SEARCH:
+ return keyctl_keyring_search((key_serial_t) arg2,
+ (const char __user *) arg3,
+ (const char __user *) arg4,
+ (key_serial_t) arg5);
+
+ case KEYCTL_READ:
+ return keyctl_read_key((key_serial_t) arg2,
+ (char __user *) arg3,
+ (size_t) arg4);
+
+ case KEYCTL_CHOWN:
+ return keyctl_chown_key((key_serial_t) arg2,
+ (uid_t) arg3,
+ (gid_t) arg4);
+
+ case KEYCTL_SETPERM:
+ return keyctl_setperm_key((key_serial_t) arg2,
+ (key_perm_t) arg3);
+
+ case KEYCTL_INSTANTIATE:
+ return keyctl_instantiate_key((key_serial_t) arg2,
+ (const void __user *) arg3,
+ (size_t) arg4,
+ (key_serial_t) arg5);
+
+ case KEYCTL_NEGATE:
+ return keyctl_negate_key((key_serial_t) arg2,
+ (unsigned) arg3,
+ (key_serial_t) arg4);
+
+ default:
+ return -EOPNOTSUPP;
+ }
+
+} /* end sys_keyctl() */
--- /dev/null
+/* keyring.c: keyring handling
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/err.h>
+#include <asm/uaccess.h>
+#include "internal.h"
+
+/*
+ * when plumbing the depths of the key tree, this sets a hard limit set on how
+ * deep we're willing to go
+ */
+#define KEYRING_SEARCH_MAX_DEPTH 6
+
+/*
+ * we keep all named keyrings in a hash to speed looking them up
+ */
+#define KEYRING_NAME_HASH_SIZE (1 << 5)
+
+static struct list_head keyring_name_hash[KEYRING_NAME_HASH_SIZE];
+static rwlock_t keyring_name_lock = RW_LOCK_UNLOCKED;
+
+static inline unsigned keyring_hash(const char *desc)
+{
+ unsigned bucket = 0;
+
+ for (; *desc; desc++)
+ bucket += (unsigned char) *desc;
+
+ return bucket & (KEYRING_NAME_HASH_SIZE - 1);
+}
+
+/*
+ * the keyring type definition
+ */
+static int keyring_instantiate(struct key *keyring,
+ const void *data, size_t datalen);
+static int keyring_duplicate(struct key *keyring, const struct key *source);
+static int keyring_match(const struct key *keyring, const void *criterion);
+static void keyring_destroy(struct key *keyring);
+static void keyring_describe(const struct key *keyring, struct seq_file *m);
+static long keyring_read(const struct key *keyring,
+ char __user *buffer, size_t buflen);
+
+struct key_type key_type_keyring = {
+ .name = "keyring",
+ .def_datalen = sizeof(struct keyring_list),
+ .instantiate = keyring_instantiate,
+ .duplicate = keyring_duplicate,
+ .match = keyring_match,
+ .destroy = keyring_destroy,
+ .describe = keyring_describe,
+ .read = keyring_read,
+};
+
+/*
+ * semaphore to serialise link/link calls to prevent two link calls in parallel
+ * introducing a cycle
+ */
+DECLARE_RWSEM(keyring_serialise_link_sem);
+
+/*****************************************************************************/
+/*
+ * publish the name of a keyring so that it can be found by name (if it has
+ * one)
+ */
+void keyring_publish_name(struct key *keyring)
+{
+ int bucket;
+
+ if (keyring->description) {
+ bucket = keyring_hash(keyring->description);
+
+ write_lock(&keyring_name_lock);
+
+ if (!keyring_name_hash[bucket].next)
+ INIT_LIST_HEAD(&keyring_name_hash[bucket]);
+
+ list_add_tail(&keyring->type_data.link,
+ &keyring_name_hash[bucket]);
+
+ write_unlock(&keyring_name_lock);
+ }
+
+} /* end keyring_publish_name() */
+
+/*****************************************************************************/
+/*
+ * initialise a keyring
+ * - we object if we were given any data
+ */
+static int keyring_instantiate(struct key *keyring,
+ const void *data, size_t datalen)
+{
+ int ret;
+
+ ret = -EINVAL;
+ if (datalen == 0) {
+ /* make the keyring available by name if it has one */
+ keyring_publish_name(keyring);
+ ret = 0;
+ }
+
+ return ret;
+
+} /* end keyring_instantiate() */
+
+/*****************************************************************************/
+/*
+ * duplicate the list of subscribed keys from a source keyring into this one
+ */
+static int keyring_duplicate(struct key *keyring, const struct key *source)
+{
+ struct keyring_list *sklist, *klist;
+ unsigned max;
+ size_t size;
+ int loop, ret;
+
+ const unsigned limit =
+ (PAGE_SIZE - sizeof(*klist)) / sizeof(struct key);
+
+ ret = 0;
+ sklist = source->payload.subscriptions;
+
+ if (sklist && sklist->nkeys > 0) {
+ max = sklist->nkeys;
+ BUG_ON(max > limit);
+
+ max = (max + 3) & ~3;
+ if (max > limit)
+ max = limit;
+
+ ret = -ENOMEM;
+ size = sizeof(*klist) + sizeof(struct key) * max;
+ klist = kmalloc(size, GFP_KERNEL);
+ if (!klist)
+ goto error;
+
+ klist->maxkeys = max;
+ klist->nkeys = sklist->nkeys;
+ memcpy(klist->keys,
+ sklist->keys,
+ sklist->nkeys * sizeof(struct key));
+
+ for (loop = klist->nkeys - 1; loop >= 0; loop--)
+ atomic_inc(&klist->keys[loop]->usage);
+
+ keyring->payload.subscriptions = klist;
+ ret = 0;
+ }
+
+ error:
+ return ret;
+
+} /* end keyring_duplicate() */
+
+/*****************************************************************************/
+/*
+ * match keyrings on their name
+ */
+static int keyring_match(const struct key *keyring, const void *description)
+{
+ return keyring->description &&
+ strcmp(keyring->description, description) == 0;
+
+} /* end keyring_match() */
+
+/*****************************************************************************/
+/*
+ * dispose of the data dangling from the corpse of a keyring
+ */
+static void keyring_destroy(struct key *keyring)
+{
+ struct keyring_list *klist;
+ int loop;
+
+ if (keyring->description) {
+ write_lock(&keyring_name_lock);
+ list_del(&keyring->type_data.link);
+ write_unlock(&keyring_name_lock);
+ }
+
+ klist = keyring->payload.subscriptions;
+ if (klist) {
+ for (loop = klist->nkeys - 1; loop >= 0; loop--)
+ key_put(klist->keys[loop]);
+ kfree(klist);
+ }
+
+} /* end keyring_destroy() */
+
+/*****************************************************************************/
+/*
+ * describe the keyring
+ */
+static void keyring_describe(const struct key *keyring, struct seq_file *m)
+{
+ struct keyring_list *klist;
+
+ if (keyring->description) {
+ seq_puts(m, keyring->description);
+ }
+ else {
+ seq_puts(m, "[anon]");
+ }
+
+ klist = keyring->payload.subscriptions;
+ if (klist)
+ seq_printf(m, ": %u/%u", klist->nkeys, klist->maxkeys);
+ else
+ seq_puts(m, ": empty");
+
+} /* end keyring_describe() */
+
+/*****************************************************************************/
+/*
+ * read a list of key IDs from the keyring's contents
+ */
+static long keyring_read(const struct key *keyring,
+ char __user *buffer, size_t buflen)
+{
+ struct keyring_list *klist;
+ struct key *key;
+ size_t qty, tmp;
+ int loop, ret;
+
+ ret = 0;
+ klist = keyring->payload.subscriptions;
+
+ if (klist) {
+ /* calculate how much data we could return */
+ qty = klist->nkeys * sizeof(key_serial_t);
+
+ if (buffer && buflen > 0) {
+ if (buflen > qty)
+ buflen = qty;
+
+ /* copy the IDs of the subscribed keys into the
+ * buffer */
+ ret = -EFAULT;
+
+ for (loop = 0; loop < klist->nkeys; loop++) {
+ key = klist->keys[loop];
+
+ tmp = sizeof(key_serial_t);
+ if (tmp > buflen)
+ tmp = buflen;
+
+ if (copy_to_user(buffer,
+ &key->serial,
+ tmp) != 0)
+ goto error;
+
+ buflen -= tmp;
+ if (buflen == 0)
+ break;
+ buffer += tmp;
+ }
+ }
+
+ ret = qty;
+ }
+
+ error:
+ return ret;
+
+} /* end keyring_read() */
+
+/*****************************************************************************/
+/*
+ * allocate a keyring and link into the destination keyring
+ */
+struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
+ int not_in_quota, struct key *dest)
+{
+ struct key *keyring;
+ int ret;
+
+ keyring = key_alloc(&key_type_keyring, description,
+ uid, gid, KEY_USR_ALL, not_in_quota);
+
+ if (!IS_ERR(keyring)) {
+ ret = key_instantiate_and_link(keyring, NULL, 0, dest);
+ if (ret < 0) {
+ key_put(keyring);
+ keyring = ERR_PTR(ret);
+ }
+ }
+
+ return keyring;
+
+} /* end keyring_alloc() */
+
+/*****************************************************************************/
+/*
+ * search the supplied keyring tree for a key that matches the criterion
+ * - perform a breadth-then-depth search up to the prescribed limit
+ * - we only find keys on which we have search permission
+ * - we use the supplied match function to see if the description (or other
+ * feature of interest) matches
+ * - we readlock the keyrings as we search down the tree
+ * - we return -EAGAIN if we didn't find any matching key
+ * - we return -ENOKEY if we only found negative matching keys
+ */
+struct key *keyring_search_aux(struct key *keyring,
+ struct key_type *type,
+ const void *description,
+ key_match_func_t match)
+{
+ struct {
+ struct key *keyring;
+ int kix;
+ } stack[KEYRING_SEARCH_MAX_DEPTH];
+
+ struct keyring_list *keylist;
+ struct timespec now;
+ struct key *key;
+ long err;
+ int sp, psp, kix;
+
+ key_check(keyring);
+
+ /* top keyring must have search permission to begin the search */
+ key = ERR_PTR(-EACCES);
+ if (!key_permission(keyring, KEY_SEARCH))
+ goto error;
+
+ key = ERR_PTR(-ENOTDIR);
+ if (keyring->type != &key_type_keyring)
+ goto error;
+
+ now = current_kernel_time();
+ err = -EAGAIN;
+ sp = 0;
+
+ /* start processing a new keyring */
+ descend:
+ read_lock(&keyring->lock);
+ if (keyring->flags & KEY_FLAG_REVOKED)
+ goto not_this_keyring;
+
+ keylist = keyring->payload.subscriptions;
+ if (!keylist)
+ goto not_this_keyring;
+
+ /* iterate through the keys in this keyring first */
+ for (kix = 0; kix < keylist->nkeys; kix++) {
+ key = keylist->keys[kix];
+
+ /* ignore keys not of this type */
+ if (key->type != type)
+ continue;
+
+ /* skip revoked keys and expired keys */
+ if (key->flags & KEY_FLAG_REVOKED)
+ continue;
+
+ if (key->expiry && now.tv_sec >= key->expiry)
+ continue;
+
+ /* keys that don't match */
+ if (!match(key, description))
+ continue;
+
+ /* key must have search permissions */
+ if (!key_permission(key, KEY_SEARCH))
+ continue;
+
+ /* we set a different error code if we find a negative key */
+ if (key->flags & KEY_FLAG_NEGATIVE) {
+ err = -ENOKEY;
+ continue;
+ }
+
+ goto found;
+ }
+
+ /* search through the keyrings nested in this one */
+ kix = 0;
+ ascend:
+ while (kix < keylist->nkeys) {
+ key = keylist->keys[kix];
+ if (key->type != &key_type_keyring)
+ goto next;
+
+ /* recursively search nested keyrings
+ * - only search keyrings for which we have search permission
+ */
+ if (sp >= KEYRING_SEARCH_MAX_DEPTH)
+ goto next;
+
+ if (!key_permission(key, KEY_SEARCH))
+ goto next;
+
+ /* evade loops in the keyring tree */
+ for (psp = 0; psp < sp; psp++)
+ if (stack[psp].keyring == keyring)
+ goto next;
+
+ /* stack the current position */
+ stack[sp].keyring = keyring;
+ stack[sp].kix = kix;
+ sp++;
+
+ /* begin again with the new keyring */
+ keyring = key;
+ goto descend;
+
+ next:
+ kix++;
+ }
+
+ /* the keyring we're looking at was disqualified or didn't contain a
+ * matching key */
+ not_this_keyring:
+ read_unlock(&keyring->lock);
+
+ if (sp > 0) {
+ /* resume the processing of a keyring higher up in the tree */
+ sp--;
+ keyring = stack[sp].keyring;
+ keylist = keyring->payload.subscriptions;
+ kix = stack[sp].kix + 1;
+ goto ascend;
+ }
+
+ key = ERR_PTR(err);
+ goto error;
+
+ /* we found a viable match */
+ found:
+ atomic_inc(&key->usage);
+ read_unlock(&keyring->lock);
+
+ /* unwind the keyring stack */
+ while (sp > 0) {
+ sp--;
+ read_unlock(&stack[sp].keyring->lock);
+ }
+
+ key_check(key);
+ error:
+ return key;
+
+} /* end keyring_search_aux() */
+
+/*****************************************************************************/
+/*
+ * search the supplied keyring tree for a key that matches the criterion
+ * - perform a breadth-then-depth search up to the prescribed limit
+ * - we only find keys on which we have search permission
+ * - we readlock the keyrings as we search down the tree
+ * - we return -EAGAIN if we didn't find any matching key
+ * - we return -ENOKEY if we only found negative matching keys
+ */
+struct key *keyring_search(struct key *keyring,
+ struct key_type *type,
+ const char *description)
+{
+ return keyring_search_aux(keyring, type, description, type->match);
+
+} /* end keyring_search() */
+
+EXPORT_SYMBOL(keyring_search);
+
+/*****************************************************************************/
+/*
+ * search the given keyring only (no recursion)
+ * - keyring must be locked by caller
+ */
+struct key *__keyring_search_one(struct key *keyring,
+ const struct key_type *ktype,
+ const char *description,
+ key_perm_t perm)
+{
+ struct keyring_list *klist;
+ struct key *key;
+ int loop;
+
+ klist = keyring->payload.subscriptions;
+ if (klist) {
+ for (loop = 0; loop < klist->nkeys; loop++) {
+ key = klist->keys[loop];
+
+ if (key->type == ktype &&
+ key->type->match(key, description) &&
+ key_permission(key, perm) &&
+ !(key->flags & KEY_FLAG_REVOKED)
+ )
+ goto found;
+ }
+ }
+
+ key = ERR_PTR(-ENOKEY);
+ goto error;
+
+ found:
+ atomic_inc(&key->usage);
+ error:
+ return key;
+
+} /* end __keyring_search_one() */
+
+/*****************************************************************************/
+/*
+ * find a keyring with the specified name
+ * - all named keyrings are searched
+ * - only find keyrings with search permission for the process
+ * - only find keyrings with a serial number greater than the one specified
+ */
+struct key *find_keyring_by_name(const char *name, key_serial_t bound)
+{
+ struct key *keyring;
+ int bucket;
+
+ keyring = ERR_PTR(-EINVAL);
+ if (!name)
+ goto error;
+
+ bucket = keyring_hash(name);
+
+ read_lock(&keyring_name_lock);
+
+ if (keyring_name_hash[bucket].next) {
+ /* search this hash bucket for a keyring with a matching name
+ * that's readable and that hasn't been revoked */
+ list_for_each_entry(keyring,
+ &keyring_name_hash[bucket],
+ type_data.link
+ ) {
+ if (keyring->flags & KEY_FLAG_REVOKED)
+ continue;
+
+ if (strcmp(keyring->description, name) != 0)
+ continue;
+
+ if (!key_permission(keyring, KEY_SEARCH))
+ continue;
+
+ /* found a potential candidate, but we still need to
+ * check the serial number */
+ if (keyring->serial <= bound)
+ continue;
+
+ /* we've got a match */
+ atomic_inc(&keyring->usage);
+ read_unlock(&keyring_name_lock);
+ goto error;
+ }
+ }
+
+ read_unlock(&keyring_name_lock);
+ keyring = ERR_PTR(-ENOKEY);
+
+ error:
+ return keyring;
+
+} /* end find_keyring_by_name() */
+
+/*****************************************************************************/
+/*
+ * see if a cycle will will be created by inserting acyclic tree B in acyclic
+ * tree A at the topmost level (ie: as a direct child of A)
+ * - since we are adding B to A at the top level, checking for cycles should
+ * just be a matter of seeing if node A is somewhere in tree B
+ */
+static int keyring_detect_cycle(struct key *A, struct key *B)
+{
+ struct {
+ struct key *subtree;
+ int kix;
+ } stack[KEYRING_SEARCH_MAX_DEPTH];
+
+ struct keyring_list *keylist;
+ struct key *subtree, *key;
+ int sp, kix, ret;
+
+ ret = -EDEADLK;
+ if (A == B)
+ goto error;
+
+ subtree = B;
+ sp = 0;
+
+ /* start processing a new keyring */
+ descend:
+ read_lock(&subtree->lock);
+ if (subtree->flags & KEY_FLAG_REVOKED)
+ goto not_this_keyring;
+
+ keylist = subtree->payload.subscriptions;
+ if (!keylist)
+ goto not_this_keyring;
+ kix = 0;
+
+ ascend:
+ /* iterate through the remaining keys in this keyring */
+ for (; kix < keylist->nkeys; kix++) {
+ key = keylist->keys[kix];
+
+ if (key == A)
+ goto cycle_detected;
+
+ /* recursively check nested keyrings */
+ if (key->type == &key_type_keyring) {
+ if (sp >= KEYRING_SEARCH_MAX_DEPTH)
+ goto too_deep;
+
+ /* stack the current position */
+ stack[sp].subtree = subtree;
+ stack[sp].kix = kix;
+ sp++;
+
+ /* begin again with the new keyring */
+ subtree = key;
+ goto descend;
+ }
+ }
+
+ /* the keyring we're looking at was disqualified or didn't contain a
+ * matching key */
+ not_this_keyring:
+ read_unlock(&subtree->lock);
+
+ if (sp > 0) {
+ /* resume the checking of a keyring higher up in the tree */
+ sp--;
+ subtree = stack[sp].subtree;
+ keylist = subtree->payload.subscriptions;
+ kix = stack[sp].kix + 1;
+ goto ascend;
+ }
+
+ ret = 0; /* no cycles detected */
+
+ error:
+ return ret;
+
+ too_deep:
+ ret = -ELOOP;
+ goto error_unwind;
+ cycle_detected:
+ ret = -EDEADLK;
+ error_unwind:
+ read_unlock(&subtree->lock);
+
+ /* unwind the keyring stack */
+ while (sp > 0) {
+ sp--;
+ read_unlock(&stack[sp].subtree->lock);
+ }
+
+ goto error;
+
+} /* end keyring_detect_cycle() */
+
+/*****************************************************************************/
+/*
+ * link a key into to a keyring
+ * - must be called with the keyring's semaphore held
+ */
+int __key_link(struct key *keyring, struct key *key)
+{
+ struct keyring_list *klist, *nklist;
+ unsigned max;
+ size_t size;
+ int ret;
+
+ ret = -EKEYREVOKED;
+ if (keyring->flags & KEY_FLAG_REVOKED)
+ goto error;
+
+ ret = -ENOTDIR;
+ if (keyring->type != &key_type_keyring)
+ goto error;
+
+ /* serialise link/link calls to prevent parallel calls causing a
+ * cycle when applied to two keyring in opposite orders */
+ down_write(&keyring_serialise_link_sem);
+
+ /* check that we aren't going to create a cycle adding one keyring to
+ * another */
+ if (key->type == &key_type_keyring) {
+ ret = keyring_detect_cycle(keyring, key);
+ if (ret < 0)
+ goto error2;
+ }
+
+ /* check that we aren't going to overrun the user's quota */
+ ret = key_payload_reserve(keyring,
+ keyring->datalen + KEYQUOTA_LINK_BYTES);
+ if (ret < 0)
+ goto error2;
+
+ klist = keyring->payload.subscriptions;
+
+ if (klist && klist->nkeys < klist->maxkeys) {
+ /* there's sufficient slack space to add directly */
+ atomic_inc(&key->usage);
+
+ write_lock(&keyring->lock);
+ klist->keys[klist->nkeys++] = key;
+ write_unlock(&keyring->lock);
+
+ ret = 0;
+ }
+ else {
+ /* grow the key list */
+ max = 4;
+ if (klist)
+ max += klist->maxkeys;
+
+ ret = -ENFILE;
+ size = sizeof(*klist) + sizeof(*key) * max;
+ if (size > PAGE_SIZE)
+ goto error3;
+
+ ret = -ENOMEM;
+ nklist = kmalloc(size, GFP_KERNEL);
+ if (!nklist)
+ goto error3;
+ nklist->maxkeys = max;
+ nklist->nkeys = 0;
+
+ if (klist) {
+ nklist->nkeys = klist->nkeys;
+ memcpy(nklist->keys,
+ klist->keys,
+ sizeof(struct key *) * klist->nkeys);
+ }
+
+ /* add the key into the new space */
+ atomic_inc(&key->usage);
+
+ write_lock(&keyring->lock);
+ keyring->payload.subscriptions = nklist;
+ nklist->keys[nklist->nkeys++] = key;
+ write_unlock(&keyring->lock);
+
+ /* dispose of the old keyring list */
+ kfree(klist);
+
+ ret = 0;
+ }
+
+ error2:
+ up_write(&keyring_serialise_link_sem);
+ error:
+ return ret;
+
+ error3:
+ /* undo the quota changes */
+ key_payload_reserve(keyring,
+ keyring->datalen - KEYQUOTA_LINK_BYTES);
+ goto error2;
+
+} /* end __key_link() */
+
+/*****************************************************************************/
+/*
+ * link a key to a keyring
+ */
+int key_link(struct key *keyring, struct key *key)
+{
+ int ret;
+
+ key_check(keyring);
+ key_check(key);
+
+ down_write(&keyring->sem);
+ ret = __key_link(keyring, key);
+ up_write(&keyring->sem);
+
+ return ret;
+
+} /* end key_link() */
+
+EXPORT_SYMBOL(key_link);
+
+/*****************************************************************************/
+/*
+ * unlink the first link to a key from a keyring
+ */
+int key_unlink(struct key *keyring, struct key *key)
+{
+ struct keyring_list *klist;
+ int loop, ret;
+
+ key_check(keyring);
+ key_check(key);
+
+ ret = -ENOTDIR;
+ if (keyring->type != &key_type_keyring)
+ goto error;
+
+ down_write(&keyring->sem);
+
+ klist = keyring->payload.subscriptions;
+ if (klist) {
+ /* search the keyring for the key */
+ for (loop = 0; loop < klist->nkeys; loop++)
+ if (klist->keys[loop] == key)
+ goto key_is_present;
+ }
+
+ up_write(&keyring->sem);
+ ret = -ENOENT;
+ goto error;
+
+ key_is_present:
+ /* adjust the user's quota */
+ key_payload_reserve(keyring,
+ keyring->datalen - KEYQUOTA_LINK_BYTES);
+
+ /* shuffle down the key pointers
+ * - it might be worth shrinking the allocated memory, but that runs
+ * the risk of ENOMEM as we would have to copy
+ */
+ write_lock(&keyring->lock);
+
+ klist->nkeys--;
+ if (loop < klist->nkeys)
+ memcpy(&klist->keys[loop],
+ &klist->keys[loop + 1],
+ (klist->nkeys - loop) * sizeof(struct key *));
+
+ write_unlock(&keyring->lock);
+
+ up_write(&keyring->sem);
+ key_put(key);
+ ret = 0;
+
+ error:
+ return ret;
+
+} /* end key_unlink() */
+
+EXPORT_SYMBOL(key_unlink);
+
+/*****************************************************************************/
+/*
+ * clear the specified process keyring
+ * - implements keyctl(KEYCTL_CLEAR)
+ */
+int keyring_clear(struct key *keyring)
+{
+ struct keyring_list *klist;
+ int loop, ret;
+
+ ret = -ENOTDIR;
+ if (keyring->type == &key_type_keyring) {
+ /* detach the pointer block with the locks held */
+ down_write(&keyring->sem);
+
+ klist = keyring->payload.subscriptions;
+ if (klist) {
+ /* adjust the quota */
+ key_payload_reserve(keyring,
+ sizeof(struct keyring_list));
+
+ write_lock(&keyring->lock);
+ keyring->payload.subscriptions = NULL;
+ write_unlock(&keyring->lock);
+ }
+
+ up_write(&keyring->sem);
+
+ /* free the keys after the locks have been dropped */
+ if (klist) {
+ for (loop = klist->nkeys - 1; loop >= 0; loop--)
+ key_put(klist->keys[loop]);
+
+ kfree(klist);
+ }
+
+ ret = 0;
+ }
+
+ return ret;
+
+} /* end keyring_clear() */
+
+EXPORT_SYMBOL(keyring_clear);
--- /dev/null
+/* proc.c: proc files for key database enumeration
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <asm/errno.h>
+#include "internal.h"
+
+#ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
+static int proc_keys_open(struct inode *inode, struct file *file);
+static void *proc_keys_start(struct seq_file *p, loff_t *_pos);
+static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos);
+static void proc_keys_stop(struct seq_file *p, void *v);
+static int proc_keys_show(struct seq_file *m, void *v);
+
+static struct seq_operations proc_keys_ops = {
+ .start = proc_keys_start,
+ .next = proc_keys_next,
+ .stop = proc_keys_stop,
+ .show = proc_keys_show,
+};
+
+static struct file_operations proc_keys_fops = {
+ .open = proc_keys_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+#endif
+
+static int proc_key_users_open(struct inode *inode, struct file *file);
+static void *proc_key_users_start(struct seq_file *p, loff_t *_pos);
+static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos);
+static void proc_key_users_stop(struct seq_file *p, void *v);
+static int proc_key_users_show(struct seq_file *m, void *v);
+
+static struct seq_operations proc_key_users_ops = {
+ .start = proc_key_users_start,
+ .next = proc_key_users_next,
+ .stop = proc_key_users_stop,
+ .show = proc_key_users_show,
+};
+
+static struct file_operations proc_key_users_fops = {
+ .open = proc_key_users_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+/*****************************************************************************/
+/*
+ * declare the /proc files
+ */
+static int __init key_proc_init(void)
+{
+ struct proc_dir_entry *p;
+
+#ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
+ p = create_proc_entry("keys", 0, NULL);
+ if (!p)
+ panic("Cannot create /proc/keys\n");
+
+ p->proc_fops = &proc_keys_fops;
+#endif
+
+ p = create_proc_entry("key-users", 0, NULL);
+ if (!p)
+ panic("Cannot create /proc/key-users\n");
+
+ p->proc_fops = &proc_key_users_fops;
+
+ return 0;
+
+} /* end key_proc_init() */
+
+__initcall(key_proc_init);
+
+/*****************************************************************************/
+/*
+ * implement "/proc/keys" to provides a list of the keys on the system
+ */
+#ifdef CONFIG_KEYS_DEBUG_PROC_KEYS
+
+static int proc_keys_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &proc_keys_ops);
+
+}
+
+static void *proc_keys_start(struct seq_file *p, loff_t *_pos)
+{
+ struct rb_node *_p;
+ loff_t pos = *_pos;
+
+ spin_lock(&key_serial_lock);
+
+ _p = rb_first(&key_serial_tree);
+ while (pos > 0 && _p) {
+ pos--;
+ _p = rb_next(_p);
+ }
+
+ return _p;
+
+}
+
+static void *proc_keys_next(struct seq_file *p, void *v, loff_t *_pos)
+{
+ (*_pos)++;
+ return rb_next((struct rb_node *) v);
+
+}
+
+static void proc_keys_stop(struct seq_file *p, void *v)
+{
+ spin_unlock(&key_serial_lock);
+}
+
+static int proc_keys_show(struct seq_file *m, void *v)
+{
+ struct rb_node *_p = v;
+ struct key *key = rb_entry(_p, struct key, serial_node);
+ struct timespec now;
+ unsigned long timo;
+ char xbuf[12];
+
+ now = current_kernel_time();
+
+ read_lock(&key->lock);
+
+ /* come up with a suitable timeout value */
+ if (key->expiry == 0) {
+ memcpy(xbuf, "perm", 5);
+ }
+ else if (now.tv_sec >= key->expiry) {
+ memcpy(xbuf, "expd", 5);
+ }
+ else {
+ timo = key->expiry - now.tv_sec;
+
+ if (timo < 60)
+ sprintf(xbuf, "%lus", timo);
+ else if (timo < 60*60)
+ sprintf(xbuf, "%lum", timo / 60);
+ else if (timo < 60*60*24)
+ sprintf(xbuf, "%luh", timo / (60*60));
+ else if (timo < 60*60*24*7)
+ sprintf(xbuf, "%lud", timo / (60*60*24));
+ else
+ sprintf(xbuf, "%luw", timo / (60*60*24*7));
+ }
+
+ seq_printf(m, "%08x %c%c%c%c%c%c %5d %4s %06x %5d %5d %-9.9s ",
+ key->serial,
+ key->flags & KEY_FLAG_INSTANTIATED ? 'I' : '-',
+ key->flags & KEY_FLAG_REVOKED ? 'R' : '-',
+ key->flags & KEY_FLAG_DEAD ? 'D' : '-',
+ key->flags & KEY_FLAG_IN_QUOTA ? 'Q' : '-',
+ key->flags & KEY_FLAG_USER_CONSTRUCT ? 'U' : '-',
+ key->flags & KEY_FLAG_NEGATIVE ? 'N' : '-',
+ atomic_read(&key->usage),
+ xbuf,
+ key->perm,
+ key->uid,
+ key->gid,
+ key->type->name);
+
+ if (key->type->describe)
+ key->type->describe(key, m);
+ seq_putc(m, '\n');
+
+ read_unlock(&key->lock);
+
+ return 0;
+
+}
+
+#endif /* CONFIG_KEYS_DEBUG_PROC_KEYS */
+
+/*****************************************************************************/
+/*
+ * implement "/proc/key-users" to provides a list of the key users
+ */
+static int proc_key_users_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &proc_key_users_ops);
+
+}
+
+static void *proc_key_users_start(struct seq_file *p, loff_t *_pos)
+{
+ struct rb_node *_p;
+ loff_t pos = *_pos;
+
+ spin_lock(&key_user_lock);
+
+ _p = rb_first(&key_user_tree);
+ while (pos > 0 && _p) {
+ pos--;
+ _p = rb_next(_p);
+ }
+
+ return _p;
+
+}
+
+static void *proc_key_users_next(struct seq_file *p, void *v, loff_t *_pos)
+{
+ (*_pos)++;
+ return rb_next((struct rb_node *) v);
+
+}
+
+static void proc_key_users_stop(struct seq_file *p, void *v)
+{
+ spin_unlock(&key_user_lock);
+}
+
+static int proc_key_users_show(struct seq_file *m, void *v)
+{
+ struct rb_node *_p = v;
+ struct key_user *user = rb_entry(_p, struct key_user, node);
+
+ seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
+ user->uid,
+ atomic_read(&user->usage),
+ atomic_read(&user->nkeys),
+ atomic_read(&user->nikeys),
+ user->qnkeys,
+ KEYQUOTA_MAX_KEYS,
+ user->qnbytes,
+ KEYQUOTA_MAX_BYTES
+ );
+
+ return 0;
+
+}
--- /dev/null
+/* process_keys.c: management of a process's keyrings
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/keyctl.h>
+#include <linux/fs.h>
+#include <linux/err.h>
+#include <asm/uaccess.h>
+#include "internal.h"
+
+/* session keyring create vs join semaphore */
+static DECLARE_MUTEX(key_session_sem);
+
+/* the root user's tracking struct */
+struct key_user root_key_user = {
+ .usage = ATOMIC_INIT(3),
+ .consq = LIST_HEAD_INIT(root_key_user.consq),
+ .lock = SPIN_LOCK_UNLOCKED,
+ .nkeys = ATOMIC_INIT(2),
+ .nikeys = ATOMIC_INIT(2),
+ .uid = 0,
+};
+
+/* the root user's UID keyring */
+struct key root_user_keyring = {
+ .usage = ATOMIC_INIT(1),
+ .serial = 2,
+ .type = &key_type_keyring,
+ .user = &root_key_user,
+ .lock = RW_LOCK_UNLOCKED,
+ .sem = __RWSEM_INITIALIZER(root_user_keyring.sem),
+ .perm = KEY_USR_ALL,
+ .flags = KEY_FLAG_INSTANTIATED,
+ .description = "_uid.0",
+#ifdef KEY_DEBUGGING
+ .magic = KEY_DEBUG_MAGIC,
+#endif
+};
+
+/* the root user's default session keyring */
+struct key root_session_keyring = {
+ .usage = ATOMIC_INIT(1),
+ .serial = 1,
+ .type = &key_type_keyring,
+ .user = &root_key_user,
+ .lock = RW_LOCK_UNLOCKED,
+ .sem = __RWSEM_INITIALIZER(root_session_keyring.sem),
+ .perm = KEY_USR_ALL,
+ .flags = KEY_FLAG_INSTANTIATED,
+ .description = "_uid_ses.0",
+#ifdef KEY_DEBUGGING
+ .magic = KEY_DEBUG_MAGIC,
+#endif
+};
+
+/*****************************************************************************/
+/*
+ * allocate the keyrings to be associated with a UID
+ */
+int alloc_uid_keyring(struct user_struct *user)
+{
+ struct key *uid_keyring, *session_keyring;
+ char buf[20];
+ int ret;
+
+ /* concoct a default session keyring */
+ sprintf(buf, "_uid_ses.%u", user->uid);
+
+ session_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, 0, NULL);
+ if (IS_ERR(session_keyring)) {
+ ret = PTR_ERR(session_keyring);
+ goto error;
+ }
+
+ /* and a UID specific keyring, pointed to by the default session
+ * keyring */
+ sprintf(buf, "_uid.%u", user->uid);
+
+ uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, 0,
+ session_keyring);
+ if (IS_ERR(uid_keyring)) {
+ key_put(session_keyring);
+ ret = PTR_ERR(uid_keyring);
+ goto error;
+ }
+
+ /* install the keyrings */
+ user->uid_keyring = uid_keyring;
+ user->session_keyring = session_keyring;
+ ret = 0;
+
+ error:
+ return ret;
+
+} /* end alloc_uid_keyring() */
+
+/*****************************************************************************/
+/*
+ * deal with the UID changing
+ */
+void switch_uid_keyring(struct user_struct *new_user)
+{
+#if 0 /* do nothing for now */
+ struct key *old;
+
+ /* switch to the new user's session keyring if we were running under
+ * root's default session keyring */
+ if (new_user->uid != 0 &&
+ current->session_keyring == &root_session_keyring
+ ) {
+ atomic_inc(&new_user->session_keyring->usage);
+
+ task_lock(current);
+ old = current->session_keyring;
+ current->session_keyring = new_user->session_keyring;
+ task_unlock(current);
+
+ key_put(old);
+ }
+#endif
+
+} /* end switch_uid_keyring() */
+
+/*****************************************************************************/
+/*
+ * install a fresh thread keyring, discarding the old one
+ */
+int install_thread_keyring(struct task_struct *tsk)
+{
+ struct key *keyring, *old;
+ char buf[20];
+ int ret;
+
+ sprintf(buf, "_tid.%u", tsk->pid);
+
+ keyring = keyring_alloc(buf, tsk->uid, tsk->gid, 1, NULL);
+ if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto error;
+ }
+
+ task_lock(tsk);
+ old = tsk->thread_keyring;
+ tsk->thread_keyring = keyring;
+ task_unlock(tsk);
+
+ ret = 0;
+
+ key_put(old);
+ error:
+ return ret;
+
+} /* end install_thread_keyring() */
+
+/*****************************************************************************/
+/*
+ * install a fresh process keyring, discarding the old one
+ */
+static int install_process_keyring(struct task_struct *tsk)
+{
+ struct key *keyring, *old;
+ char buf[20];
+ int ret;
+
+ sprintf(buf, "_pid.%u", tsk->tgid);
+
+ keyring = keyring_alloc(buf, tsk->uid, tsk->gid, 1, NULL);
+ if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto error;
+ }
+
+ task_lock(tsk);
+ old = tsk->process_keyring;
+ tsk->process_keyring = keyring;
+ task_unlock(tsk);
+
+ ret = 0;
+
+ key_put(old);
+ error:
+ return ret;
+
+} /* end install_process_keyring() */
+
+/*****************************************************************************/
+/*
+ * install a session keyring, discarding the old one
+ * - if a keyring is not supplied, an empty one is invented
+ */
+static int install_session_keyring(struct task_struct *tsk,
+ struct key *keyring)
+{
+ struct key *old;
+ char buf[20];
+ int ret;
+
+ /* create an empty session keyring */
+ if (!keyring) {
+ sprintf(buf, "_ses.%u", tsk->tgid);
+
+ keyring = keyring_alloc(buf, tsk->uid, tsk->gid, 1, NULL);
+ if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto error;
+ }
+ }
+ else {
+ atomic_inc(&keyring->usage);
+ }
+
+ /* install the keyring */
+ task_lock(tsk);
+ old = tsk->session_keyring;
+ tsk->session_keyring = keyring;
+ task_unlock(tsk);
+
+ ret = 0;
+
+ key_put(old);
+ error:
+ return ret;
+
+} /* end install_session_keyring() */
+
+/*****************************************************************************/
+/*
+ * copy the keys for fork
+ */
+int copy_keys(unsigned long clone_flags, struct task_struct *tsk)
+{
+ int ret = 0;
+
+ key_check(tsk->session_keyring);
+ key_check(tsk->process_keyring);
+ key_check(tsk->thread_keyring);
+
+ if (tsk->session_keyring)
+ atomic_inc(&tsk->session_keyring->usage);
+
+ if (tsk->process_keyring) {
+ if (clone_flags & CLONE_THREAD) {
+ atomic_inc(&tsk->process_keyring->usage);
+ }
+ else {
+ tsk->process_keyring = NULL;
+ ret = install_process_keyring(tsk);
+ }
+ }
+
+ tsk->thread_keyring = NULL;
+ return ret;
+
+} /* end copy_keys() */
+
+/*****************************************************************************/
+/*
+ * dispose of keys upon exit
+ */
+void exit_keys(struct task_struct *tsk)
+{
+ key_put(tsk->session_keyring);
+ key_put(tsk->process_keyring);
+ key_put(tsk->thread_keyring);
+
+} /* end exit_keys() */
+
+/*****************************************************************************/
+/*
+ * deal with execve()
+ */
+int exec_keys(struct task_struct *tsk)
+{
+ struct key *old;
+
+ /* newly exec'd tasks don't get a thread keyring */
+ task_lock(tsk);
+ old = tsk->thread_keyring;
+ tsk->thread_keyring = NULL;
+ task_unlock(tsk);
+
+ key_put(old);
+
+ /* newly exec'd tasks get a fresh process keyring */
+ return install_process_keyring(tsk);
+
+} /* end exec_keys() */
+
+/*****************************************************************************/
+/*
+ * deal with SUID programs
+ * - we might want to make this invent a new session keyring
+ */
+int suid_keys(struct task_struct *tsk)
+{
+ return 0;
+
+} /* end suid_keys() */
+
+/*****************************************************************************/
+/*
+ * the filesystem user ID changed
+ */
+void key_fsuid_changed(struct task_struct *tsk)
+{
+ /* update the ownership of the process keyring */
+ if (tsk->process_keyring) {
+ down_write(&tsk->process_keyring->sem);
+ write_lock(&tsk->process_keyring->lock);
+ tsk->process_keyring->uid = tsk->fsuid;
+ write_unlock(&tsk->process_keyring->lock);
+ up_write(&tsk->process_keyring->sem);
+ }
+
+ /* update the ownership of the thread keyring */
+ if (tsk->thread_keyring) {
+ down_write(&tsk->thread_keyring->sem);
+ write_lock(&tsk->thread_keyring->lock);
+ tsk->thread_keyring->uid = tsk->fsuid;
+ write_unlock(&tsk->thread_keyring->lock);
+ up_write(&tsk->thread_keyring->sem);
+ }
+
+} /* end key_fsuid_changed() */
+
+/*****************************************************************************/
+/*
+ * the filesystem group ID changed
+ */
+void key_fsgid_changed(struct task_struct *tsk)
+{
+ /* update the ownership of the process keyring */
+ if (tsk->process_keyring) {
+ down_write(&tsk->process_keyring->sem);
+ write_lock(&tsk->process_keyring->lock);
+ tsk->process_keyring->gid = tsk->fsgid;
+ write_unlock(&tsk->process_keyring->lock);
+ up_write(&tsk->process_keyring->sem);
+ }
+
+ /* update the ownership of the thread keyring */
+ if (tsk->thread_keyring) {
+ down_write(&tsk->thread_keyring->sem);
+ write_lock(&tsk->thread_keyring->lock);
+ tsk->thread_keyring->gid = tsk->fsgid;
+ write_unlock(&tsk->thread_keyring->lock);
+ up_write(&tsk->thread_keyring->sem);
+ }
+
+} /* end key_fsgid_changed() */
+
+/*****************************************************************************/
+/*
+ * search the process keyrings for the first matching key
+ * - we use the supplied match function to see if the description (or other
+ * feature of interest) matches
+ * - we return -EAGAIN if we didn't find any matching key
+ * - we return -ENOKEY if we found only negative matching keys
+ */
+struct key *search_process_keyrings_aux(struct key_type *type,
+ const void *description,
+ key_match_func_t match)
+{
+ struct task_struct *tsk = current;
+ struct key *key, *ret, *err, *session;
+
+ /* we want to return -EAGAIN or -ENOKEY if any of the keyrings were
+ * searchable, but we failed to find a key or we found a negative key;
+ * otherwise we want to return a sample error (probably -EACCES) if
+ * none of the keyrings were searchable
+ *
+ * in terms of priority: success > -ENOKEY > -EAGAIN > other error
+ */
+ key = NULL;
+ ret = NULL;
+ err = ERR_PTR(-EAGAIN);
+
+ /* search the thread keyring first */
+ if (tsk->thread_keyring) {
+ key = keyring_search_aux(tsk->thread_keyring, type,
+ description, match);
+ if (!IS_ERR(key))
+ goto found;
+
+ switch (PTR_ERR(key)) {
+ case -EAGAIN: /* no key */
+ if (ret)
+ break;
+ case -ENOKEY: /* negative key */
+ ret = key;
+ break;
+ default:
+ err = key;
+ break;
+ }
+ }
+
+ /* search the process keyring second */
+ if (tsk->process_keyring) {
+ key = keyring_search_aux(tsk->process_keyring, type,
+ description, match);
+ if (!IS_ERR(key))
+ goto found;
+
+ switch (PTR_ERR(key)) {
+ case -EAGAIN: /* no key */
+ if (ret)
+ break;
+ case -ENOKEY: /* negative key */
+ ret = key;
+ break;
+ default:
+ err = key;
+ break;
+ }
+ }
+
+ /* search the session keyring last */
+ session = tsk->session_keyring;
+ if (!session)
+ session = tsk->user->session_keyring;
+
+ key = keyring_search_aux(session, type,
+ description, match);
+ if (!IS_ERR(key))
+ goto found;
+
+ switch (PTR_ERR(key)) {
+ case -EAGAIN: /* no key */
+ if (ret)
+ break;
+ case -ENOKEY: /* negative key */
+ ret = key;
+ break;
+ default:
+ err = key;
+ break;
+ }
+
+ /* no key - decide on the error we're going to go for */
+ key = ret ? ret : err;
+
+ found:
+ return key;
+
+} /* end search_process_keyrings_aux() */
+
+/*****************************************************************************/
+/*
+ * search the process keyrings for the first matching key
+ * - we return -EAGAIN if we didn't find any matching key
+ * - we return -ENOKEY if we found only negative matching keys
+ */
+struct key *search_process_keyrings(struct key_type *type,
+ const char *description)
+{
+ return search_process_keyrings_aux(type, description, type->match);
+
+} /* end search_process_keyrings() */
+
+/*****************************************************************************/
+/*
+ * lookup a key given a key ID from userspace with a given permissions mask
+ * - don't create special keyrings unless so requested
+ * - partially constructed keys aren't found unless requested
+ */
+struct key *lookup_user_key(key_serial_t id, int create, int partial,
+ key_perm_t perm)
+{
+ struct task_struct *tsk = current;
+ struct key *key;
+ int ret;
+
+ key = ERR_PTR(-ENOKEY);
+
+ switch (id) {
+ case KEY_SPEC_THREAD_KEYRING:
+ if (!tsk->thread_keyring) {
+ if (!create)
+ goto error;
+
+ ret = install_thread_keyring(tsk);
+ if (ret < 0) {
+ key = ERR_PTR(ret);
+ goto error;
+ }
+ }
+
+ key = tsk->thread_keyring;
+ atomic_inc(&key->usage);
+ break;
+
+ case KEY_SPEC_PROCESS_KEYRING:
+ if (!tsk->process_keyring) {
+ if (!create)
+ goto error;
+
+ ret = install_process_keyring(tsk);
+ if (ret < 0) {
+ key = ERR_PTR(ret);
+ goto error;
+ }
+ }
+
+ key = tsk->process_keyring;
+ atomic_inc(&key->usage);
+ break;
+
+ case KEY_SPEC_SESSION_KEYRING:
+ if (!tsk->session_keyring) {
+ /* always install a session keyring upon access if one
+ * doesn't exist yet */
+ ret = install_session_keyring(
+ tsk, tsk->user->session_keyring);
+ if (ret < 0)
+ goto error;
+ }
+
+ key = tsk->session_keyring;
+ atomic_inc(&key->usage);
+ break;
+
+ case KEY_SPEC_USER_KEYRING:
+ key = tsk->user->uid_keyring;
+ atomic_inc(&key->usage);
+ break;
+
+ case KEY_SPEC_USER_SESSION_KEYRING:
+ key = tsk->user->session_keyring;
+ atomic_inc(&key->usage);
+ break;
+
+ case KEY_SPEC_GROUP_KEYRING:
+ /* group keyrings are not yet supported */
+ key = ERR_PTR(-EINVAL);
+ goto error;
+
+ default:
+ key = ERR_PTR(-EINVAL);
+ if (id < 1)
+ goto error;
+
+ key = key_lookup(id);
+ if (IS_ERR(key))
+ goto error;
+ break;
+ }
+
+ /* check the status and permissions */
+ if (perm) {
+ ret = key_validate(key);
+ if (ret < 0)
+ goto invalid_key;
+ }
+
+ ret = -EIO;
+ if (!partial && !(key->flags & KEY_FLAG_INSTANTIATED))
+ goto invalid_key;
+
+ ret = -EACCES;
+ if (!key_permission(key, perm))
+ goto invalid_key;
+
+ error:
+ return key;
+
+ invalid_key:
+ key_put(key);
+ key = ERR_PTR(ret);
+ goto error;
+
+} /* end lookup_user_key() */
+
+/*****************************************************************************/
+/*
+ * join the named keyring as the session keyring if possible, or attempt to
+ * create a new one of that name if not
+ * - if the name is NULL, an empty anonymous keyring is installed instead
+ * - named session keyring joining is done with a semaphore held
+ */
+long join_session_keyring(const char *name)
+{
+ struct task_struct *tsk = current;
+ struct key *keyring;
+ long ret;
+
+ /* if no name is provided, install an anonymous keyring */
+ if (!name) {
+ ret = install_session_keyring(tsk, NULL);
+ if (ret < 0)
+ goto error;
+
+ ret = tsk->session_keyring->serial;
+ goto error;
+ }
+
+ /* allow the user to join or create a named keyring */
+ down(&key_session_sem);
+
+ /* look for an existing keyring of this name */
+ keyring = find_keyring_by_name(name, 0);
+ if (PTR_ERR(keyring) == -ENOKEY) {
+ /* not found - try and create a new one */
+ keyring = keyring_alloc(name, tsk->uid, tsk->gid, 0, NULL);
+ if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto error;
+ }
+ }
+ else if (IS_ERR(keyring)) {
+ ret = PTR_ERR(keyring);
+ goto error2;
+ }
+
+ /* we've got a keyring - now to install it */
+ ret = install_session_keyring(tsk, keyring);
+ if (ret < 0)
+ goto error2;
+
+ key_put(keyring);
+
+ ret = tsk->session_keyring->serial;
+
+ error2:
+ up(&key_session_sem);
+ error:
+ return ret;
+
+} /* end join_session_keyring() */
--- /dev/null
+/* request_key.c: request a key from userspace
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/kmod.h>
+#include <linux/err.h>
+#include "internal.h"
+
+struct key_construction {
+ struct list_head link; /* link in construction queue */
+ struct key *key; /* key being constructed */
+};
+
+/* when waiting for someone else's keys, you get added to this */
+DECLARE_WAIT_QUEUE_HEAD(request_key_conswq);
+
+/*****************************************************************************/
+/*
+ * request userspace finish the construction of a key
+ * - execute "/sbin/request-key <op> <key> <uid> <gid> <keyring> <keyring> <keyring> <info>"
+ * - if callout_info is an empty string, it'll be rendered as a "-" instead
+ */
+static int call_request_key(struct key *key,
+ const char *op,
+ const char *callout_info)
+{
+ struct task_struct *tsk = current;
+ char *argv[10], *envp[3], uid_str[12], gid_str[12];
+ char key_str[12], keyring_str[3][12];
+ int i;
+
+ /* record the UID and GID */
+ sprintf(uid_str, "%d", current->fsuid);
+ sprintf(gid_str, "%d", current->fsgid);
+
+ /* we say which key is under construction */
+ sprintf(key_str, "%d", key->serial);
+
+ /* we specify the process's default keyrings */
+ task_lock(current);
+ sprintf(keyring_str[0], "%d",
+ tsk->thread_keyring ? tsk->thread_keyring->serial : 0);
+ sprintf(keyring_str[1], "%d",
+ tsk->process_keyring ? tsk->process_keyring->serial : 0);
+ sprintf(keyring_str[2], "%d",
+ (tsk->session_keyring ?
+ tsk->session_keyring->serial :
+ tsk->user->session_keyring->serial));
+ task_unlock(tsk);
+
+ /* set up a minimal environment */
+ i = 0;
+ envp[i++] = "HOME=/";
+ envp[i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
+ envp[i] = NULL;
+
+ /* set up the argument list */
+ i = 0;
+ argv[i++] = "/sbin/request-key";
+ argv[i++] = (char *) op;
+ argv[i++] = key_str;
+ argv[i++] = uid_str;
+ argv[i++] = gid_str;
+ argv[i++] = keyring_str[0];
+ argv[i++] = keyring_str[1];
+ argv[i++] = keyring_str[2];
+ argv[i++] = callout_info[0] ? (char *) callout_info : "-";
+ argv[i] = NULL;
+
+ /* do it */
+ return call_usermodehelper(argv[0], argv, envp, 1);
+
+} /* end call_request_key() */
+
+/*****************************************************************************/
+/*
+ * call out to userspace for the key
+ * - called with the construction sem held, but the sem is dropped here
+ * - we ignore program failure and go on key status instead
+ */
+static struct key *__request_key_construction(struct key_type *type,
+ const char *description,
+ const char *callout_info)
+{
+ struct key_construction cons;
+ struct timespec now;
+ struct key *key;
+ int ret, negative;
+
+ /* create a key and add it to the queue */
+ key = key_alloc(type, description,
+ current->fsuid, current->fsgid, KEY_USR_ALL, 0);
+ if (IS_ERR(key))
+ goto alloc_failed;
+
+ write_lock(&key->lock);
+ key->flags |= KEY_FLAG_USER_CONSTRUCT;
+ write_unlock(&key->lock);
+
+ cons.key = key;
+ list_add_tail(&cons.link, &key->user->consq);
+
+ /* we drop the construction sem here on behalf of the caller */
+ up_write(&key_construction_sem);
+
+ /* make the call */
+ ret = call_request_key(key, "create", callout_info);
+ if (ret < 0)
+ goto request_failed;
+
+ /* if the key wasn't instantiated, then we want to give an error */
+ ret = -ENOKEY;
+ if (!(key->flags & KEY_FLAG_INSTANTIATED))
+ goto request_failed;
+
+ down_write(&key_construction_sem);
+ list_del(&cons.link);
+ up_write(&key_construction_sem);
+
+ /* also give an error if the key was negatively instantiated */
+ check_not_negative:
+ if (key->flags & KEY_FLAG_NEGATIVE) {
+ key_put(key);
+ key = ERR_PTR(-ENOKEY);
+ }
+
+ out:
+ return key;
+
+ request_failed:
+ /* it wasn't instantiated
+ * - remove from construction queue
+ * - mark the key as dead
+ */
+ negative = 0;
+ down_write(&key_construction_sem);
+
+ list_del(&cons.link);
+
+ write_lock(&key->lock);
+ key->flags &= ~KEY_FLAG_USER_CONSTRUCT;
+
+ /* check it didn't get instantiated between the check and the down */
+ if (!(key->flags & KEY_FLAG_INSTANTIATED)) {
+ key->flags |= KEY_FLAG_INSTANTIATED | KEY_FLAG_NEGATIVE;
+ negative = 1;
+ }
+
+ write_unlock(&key->lock);
+ up_write(&key_construction_sem);
+
+ if (!negative)
+ goto check_not_negative; /* surprisingly, the key got
+ * instantiated */
+
+ /* set the timeout and store in the session keyring if we can */
+ now = current_kernel_time();
+ key->expiry = now.tv_sec + key_negative_timeout;
+
+ if (current->session_keyring)
+ key_link(current->session_keyring, key);
+ key_put(key);
+
+ /* notify anyone who was waiting */
+ wake_up_all(&request_key_conswq);
+
+ key = ERR_PTR(ret);
+ goto out;
+
+ alloc_failed:
+ up_write(&key_construction_sem);
+ goto out;
+
+} /* end __request_key_construction() */
+
+/*****************************************************************************/
+/*
+ * call out to userspace to request the key
+ * - we check the construction queue first to see if an appropriate key is
+ * already being constructed by userspace
+ */
+static struct key *request_key_construction(struct key_type *type,
+ const char *description,
+ struct key_user *user,
+ const char *callout_info)
+{
+ struct key_construction *pcons;
+ struct key *key, *ckey;
+
+ DECLARE_WAITQUEUE(myself, current);
+
+ /* see if there's such a key under construction already */
+ down_write(&key_construction_sem);
+
+ list_for_each_entry(pcons, &user->consq, link) {
+ ckey = pcons->key;
+
+ if (ckey->type != type)
+ continue;
+
+ if (type->match(ckey, description))
+ goto found_key_under_construction;
+ }
+
+ /* see about getting userspace to construct the key */
+ key = __request_key_construction(type, description, callout_info);
+ error:
+ return key;
+
+ /* someone else has the same key under construction
+ * - we want to keep an eye on their key
+ */
+ found_key_under_construction:
+ atomic_inc(&ckey->usage);
+ up_write(&key_construction_sem);
+
+ /* wait for the key to be completed one way or another */
+ add_wait_queue(&request_key_conswq, &myself);
+
+ for (;;) {
+ set_current_state(TASK_UNINTERRUPTIBLE);
+ if (!(ckey->flags & KEY_FLAG_USER_CONSTRUCT))
+ break;
+ schedule();
+ }
+
+ set_current_state(TASK_RUNNING);
+ remove_wait_queue(&request_key_conswq, &myself);
+
+ /* we'll need to search this process's keyrings to see if the key is
+ * now there since we can't automatically assume it's also available
+ * there */
+ key_put(ckey);
+ ckey = NULL;
+
+ key = NULL; /* request a retry */
+ goto error;
+
+} /* end request_key_construction() */
+
+/*****************************************************************************/
+/*
+ * request a key
+ * - search the process's keyrings
+ * - check the list of keys being created or updated
+ * - call out to userspace for a key if requested (supplementary info can be
+ * passed)
+ */
+struct key *request_key(struct key_type *type,
+ const char *description,
+ const char *callout_info)
+{
+ struct key_user *user;
+ struct key *key;
+
+ /* search all the process keyrings for a key */
+ key = search_process_keyrings_aux(type, description, type->match);
+
+ if (PTR_ERR(key) == -EAGAIN) {
+ /* the search failed, but the keyrings were searchable, so we
+ * should consult userspace if we can */
+ key = ERR_PTR(-ENOKEY);
+ if (!callout_info)
+ goto error;
+
+ /* - get hold of the user's construction queue */
+ user = key_user_lookup(current->fsuid);
+ if (IS_ERR(user)) {
+ key = ERR_PTR(PTR_ERR(user));
+ goto error;
+ }
+
+ for (;;) {
+ /* ask userspace (returns NULL if it waited on a key
+ * being constructed) */
+ key = request_key_construction(type, description,
+ user, callout_info);
+ if (key)
+ break;
+
+ /* someone else made the key we want, so we need to
+ * search again as it might now be available to us */
+ key = search_process_keyrings_aux(type, description,
+ type->match);
+ if (PTR_ERR(key) != -EAGAIN)
+ break;
+ }
+
+ key_user_put(user);
+ }
+
+ error:
+ return key;
+
+} /* end request_key() */
+
+EXPORT_SYMBOL(request_key);
+
+/*****************************************************************************/
+/*
+ * validate a key
+ */
+int key_validate(struct key *key)
+{
+ struct timespec now;
+ int ret = 0;
+
+ if (key) {
+ /* check it's still accessible */
+ ret = -EKEYREVOKED;
+ if (key->flags & (KEY_FLAG_REVOKED | KEY_FLAG_DEAD))
+ goto error;
+
+ /* check it hasn't expired */
+ ret = 0;
+ if (key->expiry) {
+ now = current_kernel_time();
+ if (now.tv_sec >= key->expiry)
+ ret = -EKEYEXPIRED;
+ }
+ }
+
+ error:
+ return ret;
+
+} /* end key_validate() */
+
+EXPORT_SYMBOL(key_validate);
--- /dev/null
+/* user_defined.c: user defined key type
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/err.h>
+#include <asm/uaccess.h>
+#include "internal.h"
+
+static int user_instantiate(struct key *key, const void *data, size_t datalen);
+static int user_duplicate(struct key *key, const struct key *source);
+static int user_update(struct key *key, const void *data, size_t datalen);
+static int user_match(const struct key *key, const void *criterion);
+static void user_destroy(struct key *key);
+static void user_describe(const struct key *user, struct seq_file *m);
+static long user_read(const struct key *key,
+ char __user *buffer, size_t buflen);
+
+/*
+ * user defined keys take an arbitrary string as the description and an
+ * arbitrary blob of data as the payload
+ */
+struct key_type key_type_user = {
+ .name = "user",
+ .instantiate = user_instantiate,
+ .duplicate = user_duplicate,
+ .update = user_update,
+ .match = user_match,
+ .destroy = user_destroy,
+ .describe = user_describe,
+ .read = user_read,
+};
+
+/*****************************************************************************/
+/*
+ * instantiate a user defined key
+ */
+static int user_instantiate(struct key *key, const void *data, size_t datalen)
+{
+ int ret;
+
+ ret = -EINVAL;
+ if (datalen <= 0 || datalen > 32767 || !data)
+ goto error;
+
+ ret = key_payload_reserve(key, datalen);
+ if (ret < 0)
+ goto error;
+
+ /* attach the data */
+ ret = -ENOMEM;
+ key->payload.data = kmalloc(datalen, GFP_KERNEL);
+ if (!key->payload.data)
+ goto error;
+
+ memcpy(key->payload.data, data, datalen);
+ ret = 0;
+
+ error:
+ return ret;
+
+} /* end user_instantiate() */
+
+/*****************************************************************************/
+/*
+ * duplicate a user defined key
+ */
+static int user_duplicate(struct key *key, const struct key *source)
+{
+ int ret;
+
+ /* just copy the payload */
+ ret = -ENOMEM;
+ key->payload.data = kmalloc(source->datalen, GFP_KERNEL);
+
+ if (key->payload.data) {
+ key->datalen = source->datalen;
+ memcpy(key->payload.data, source->payload.data, source->datalen);
+ ret = 0;
+ }
+
+ return ret;
+
+} /* end user_duplicate() */
+
+/*****************************************************************************/
+/*
+ * update a user defined key
+ */
+static int user_update(struct key *key, const void *data, size_t datalen)
+{
+ void *new, *zap;
+ int ret;
+
+ ret = -EINVAL;
+ if (datalen <= 0 || datalen > 32767 || !data)
+ goto error;
+
+ /* copy the data */
+ ret = -ENOMEM;
+ new = kmalloc(datalen, GFP_KERNEL);
+ if (!new)
+ goto error;
+
+ memcpy(new, data, datalen);
+
+ /* check the quota and attach the new data */
+ zap = new;
+ write_lock(&key->lock);
+
+ ret = key_payload_reserve(key, datalen);
+
+ if (ret == 0) {
+ /* attach the new data, displacing the old */
+ zap = key->payload.data;
+ key->payload.data = new;
+ key->expiry = 0;
+ }
+
+ write_unlock(&key->lock);
+ kfree(zap);
+
+ error:
+ return ret;
+
+} /* end user_update() */
+
+/*****************************************************************************/
+/*
+ * match users on their name
+ */
+static int user_match(const struct key *key, const void *description)
+{
+ return strcmp(key->description, description) == 0;
+
+} /* end user_match() */
+
+/*****************************************************************************/
+/*
+ * dispose of the data dangling from the corpse of a user
+ */
+static void user_destroy(struct key *key)
+{
+ kfree(key->payload.data);
+
+} /* end user_destroy() */
+
+/*****************************************************************************/
+/*
+ * describe the user
+ */
+static void user_describe(const struct key *key, struct seq_file *m)
+{
+ seq_puts(m, key->description);
+
+ seq_printf(m, ": %u", key->datalen);
+
+} /* end user_describe() */
+
+/*****************************************************************************/
+/*
+ * read the key data
+ */
+static long user_read(const struct key *key,
+ char __user *buffer, size_t buflen)
+{
+ long ret = key->datalen;
+
+ /* we can return the data as is */
+ if (buffer && buflen > 0) {
+ if (buflen > key->datalen)
+ buflen = key->datalen;
+
+ if (copy_to_user(buffer, key->payload.data, buflen) != 0)
+ ret = -EFAULT;
+ }
+
+ return ret;
+
+} /* end user_read() */
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