Handle mismatched open calls

commit 38bd49064a1ecb67baad33598e3d824448ab11ec upstream.

A signal can interrupt a SendReceive call which result in incoming
responses to the call being ignored. This is a problem for calls such as
open which results in the successful response being ignored. This
results in an open file resource on the server.

The patch looks into responses which were cancelled after being sent and
in case of successful open closes the open fids.

For this patch, the check is only done in SendReceive2()

RH-bz: 1403319

Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Acked-by: Sachin Prabhu <sprabhu@redhat.com>
Signed-off-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 7c84133441d45071740bd9dcb51355b4f667ca5a..99745da9cd90a30f77102b1b279b9ebb53fe103d 100644 (file)
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -223,6 +223,7 @@ struct smb_version_operations {
        /* verify the message */
        int (*check_message)(char *, unsigned int);
        bool (*is_oplock_break)(char *, struct TCP_Server_Info *);
+       int (*handle_cancelled_mid)(char *, struct TCP_Server_Info *);
        void (*downgrade_oplock)(struct TCP_Server_Info *,
                                        struct cifsInodeInfo *, bool);
        /* process transaction2 response */
@@ -1264,12 +1265,19 @@ struct mid_q_entry {
        void *callback_data;      /* general purpose pointer for callback */
        void *resp_buf;         /* pointer to received SMB header */
        int mid_state;  /* wish this were enum but can not pass to wait_event */
+       unsigned int mid_flags;
        __le16 command;         /* smb command code */
        bool large_buf:1;       /* if valid response, is pointer to large buf */
        bool multiRsp:1;        /* multiple trans2 responses for one request  */
        bool multiEnd:1;        /* both received */
 };
 
+struct close_cancelled_open {
+       struct cifs_fid         fid;
+       struct cifs_tcon        *tcon;
+       struct work_struct      work;
+};
+
 /*     Make code in transport.c a little cleaner by moving
        update of optional stats into function below */
 #ifdef CONFIG_CIFS_STATS2
@@ -1401,6 +1409,9 @@ static inline void free_dfs_info_array(struct dfs_info3_param *param,
 #define   MID_RESPONSE_MALFORMED 0x10
 #define   MID_SHUTDOWN          0x20
 
+/* Flags */
+#define   MID_WAIT_CANCELLED    1 /* Cancelled while waiting for response */
+
 /* Types of response buffer returned from SendReceive2 */
 #define   CIFS_NO_BUFFER        0    /* Response buffer not returned */
 #define   CIFS_SMALL_BUFFER     1

diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 9924c8cbe70f11a84e2ae3bd618fe52ff8a3d115..845148d017d2c53128db91310c66cfbb99558c0f 100644 (file)
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1422,6 +1422,8 @@ cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 
        length = discard_remaining_data(server);
        dequeue_mid(mid, rdata->result);
+       mid->resp_buf = server->smallbuf;
+       server->smallbuf = NULL;
        return length;
 }
 
@@ -1536,6 +1538,8 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
                return cifs_readv_discard(server, mid);
 
        dequeue_mid(mid, false);
+       mid->resp_buf = server->smallbuf;
+       server->smallbuf = NULL;
        return length;
 }
 

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 8770f4de457bf03ae3d08d65a77df24e2c2024b2..f78d13ba7d19debe75ce49c0cc7b05304d827119 100644 (file)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -914,10 +914,19 @@ cifs_demultiplex_thread(void *p)
 
                server->lstrp = jiffies;
                if (mid_entry != NULL) {
+                       if ((mid_entry->mid_flags & MID_WAIT_CANCELLED) &&
+                            mid_entry->mid_state == MID_RESPONSE_RECEIVED &&
+                                       server->ops->handle_cancelled_mid)
+                               server->ops->handle_cancelled_mid(
+                                                       mid_entry->resp_buf,
+                                                       server);
+
                        if (!mid_entry->multiRsp || mid_entry->multiEnd)
                                mid_entry->callback(mid_entry);
-               } else if (!server->ops->is_oplock_break ||
-                          !server->ops->is_oplock_break(buf, server)) {
+               } else if (server->ops->is_oplock_break &&
+                          server->ops->is_oplock_break(buf, server)) {
+                       cifs_dbg(FYI, "Received oplock break\n");
+               } else {
                        cifs_dbg(VFS, "No task to wake, unknown frame received! NumMids %d\n",
                                 atomic_read(&midCount));
                        cifs_dump_mem("Received Data is: ", buf,

diff --git a/fs/cifs/smb2misc.c b/fs/cifs/smb2misc.c
index 1a08a34838fc9772e2a62ff5dd69b9431d38f453..b35c1398d459ef00206f06e6c7d623ef49b8b398 100644 (file)
--- a/fs/cifs/smb2misc.c
+++ b/fs/cifs/smb2misc.c
@@ -628,3 +628,47 @@ smb2_is_valid_oplock_break(char *buffer, struct TCP_Server_Info *server)
        cifs_dbg(FYI, "Can not process oplock break for non-existent connection\n");
        return false;
 }
+
+void
+smb2_cancelled_close_fid(struct work_struct *work)
+{
+       struct close_cancelled_open *cancelled = container_of(work,
+                                       struct close_cancelled_open, work);
+
+       cifs_dbg(VFS, "Close unmatched open\n");
+
+       SMB2_close(0, cancelled->tcon, cancelled->fid.persistent_fid,
+                  cancelled->fid.volatile_fid);
+       cifs_put_tcon(cancelled->tcon);
+       kfree(cancelled);
+}
+
+int
+smb2_handle_cancelled_mid(char *buffer, struct TCP_Server_Info *server)
+{
+       struct smb2_hdr *hdr = (struct smb2_hdr *)buffer;
+       struct smb2_create_rsp *rsp = (struct smb2_create_rsp *)buffer;
+       struct cifs_tcon *tcon;
+       struct close_cancelled_open *cancelled;
+
+       if (hdr->Command != SMB2_CREATE || hdr->Status != STATUS_SUCCESS)
+               return 0;
+
+       cancelled = kzalloc(sizeof(*cancelled), GFP_KERNEL);
+       if (!cancelled)
+               return -ENOMEM;
+
+       tcon = smb2_find_smb_tcon(server, hdr->SessionId, hdr->TreeId);
+       if (!tcon) {
+               kfree(cancelled);
+               return -ENOENT;
+       }
+
+       cancelled->fid.persistent_fid = rsp->PersistentFileId;
+       cancelled->fid.volatile_fid = rsp->VolatileFileId;
+       cancelled->tcon = tcon;
+       INIT_WORK(&cancelled->work, smb2_cancelled_close_fid);
+       queue_work(cifsiod_wq, &cancelled->work);
+
+       return 0;
+}

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index aa68b34301ec4cc46c71a2dbf20dfd6820935caa..56dba5249d5f44f341ba86f581aba144542e92af 100644 (file)
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -1461,6 +1461,8 @@ struct smb_version_operations smb21_operations = {
        .clear_stats = smb2_clear_stats,
        .print_stats = smb2_print_stats,
        .is_oplock_break = smb2_is_valid_oplock_break,
+       .handle_cancelled_mid = smb2_handle_cancelled_mid,
+       .handle_cancelled_mid = smb2_handle_cancelled_mid,
        .downgrade_oplock = smb2_downgrade_oplock,
        .need_neg = smb2_need_neg,
        .negotiate = smb2_negotiate,
@@ -1542,6 +1544,8 @@ struct smb_version_operations smb30_operations = {
        .print_stats = smb2_print_stats,
        .dump_share_caps = smb2_dump_share_caps,
        .is_oplock_break = smb2_is_valid_oplock_break,
+       .handle_cancelled_mid = smb2_handle_cancelled_mid,
+       .handle_cancelled_mid = smb2_handle_cancelled_mid,
        .downgrade_oplock = smb2_downgrade_oplock,
        .need_neg = smb2_need_neg,
        .negotiate = smb2_negotiate,

diff --git a/fs/cifs/smb2proto.h b/fs/cifs/smb2proto.h
index 0a406ae78129a3fbd5676a426ca0562bd5eaea23..adc5234486c37b979ddeea1d834818a6f0ecef4d 100644 (file)
--- a/fs/cifs/smb2proto.h
+++ b/fs/cifs/smb2proto.h
@@ -47,6 +47,10 @@ extern struct mid_q_entry *smb2_setup_request(struct cifs_ses *ses,
                              struct smb_rqst *rqst);
 extern struct mid_q_entry *smb2_setup_async_request(
                        struct TCP_Server_Info *server, struct smb_rqst *rqst);
+extern struct cifs_ses *smb2_find_smb_ses(struct TCP_Server_Info *server,
+                                          __u64 ses_id);
+extern struct cifs_tcon *smb2_find_smb_tcon(struct TCP_Server_Info *server,
+                                               __u64 ses_id, __u32  tid);
 extern int smb2_calc_signature(struct smb_rqst *rqst,
                                struct TCP_Server_Info *server);
 extern int smb3_calc_signature(struct smb_rqst *rqst,
@@ -157,6 +161,9 @@ extern int SMB2_set_compression(const unsigned int xid, struct cifs_tcon *tcon,
 extern int SMB2_oplock_break(const unsigned int xid, struct cifs_tcon *tcon,
                             const u64 persistent_fid, const u64 volatile_fid,
                             const __u8 oplock_level);
+extern int smb2_handle_cancelled_mid(char *buffer,
+                                       struct TCP_Server_Info *server);
+void smb2_cancelled_close_fid(struct work_struct *work);
 extern int SMB2_QFS_info(const unsigned int xid, struct cifs_tcon *tcon,
                         u64 persistent_file_id, u64 volatile_file_id,
                         struct kstatfs *FSData);

diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
index 5111e7272db62e718fcb3d968af48083d598bccf..0767a1ca9f536b9c45c7308ccc14826f1ef41fc8 100644 (file)
--- a/fs/cifs/smb2transport.c
+++ b/fs/cifs/smb2transport.c
@@ -115,22 +115,68 @@ smb3_crypto_shash_allocate(struct TCP_Server_Info *server)
 }
 
 static struct cifs_ses *
-smb2_find_smb_ses(struct smb2_hdr *smb2hdr, struct TCP_Server_Info *server)
+smb2_find_smb_ses_unlocked(struct TCP_Server_Info *server, __u64 ses_id)
 {
        struct cifs_ses *ses;
 
-       spin_lock(&cifs_tcp_ses_lock);
        list_for_each_entry(ses, &server->smb_ses_list, smb_ses_list) {
-               if (ses->Suid != smb2hdr->SessionId)
+               if (ses->Suid != ses_id)
                        continue;
-               spin_unlock(&cifs_tcp_ses_lock);
                return ses;
        }
+
+       return NULL;
+}
+
+struct cifs_ses *
+smb2_find_smb_ses(struct TCP_Server_Info *server, __u64 ses_id)
+{
+       struct cifs_ses *ses;
+
+       spin_lock(&cifs_tcp_ses_lock);
+       ses = smb2_find_smb_ses_unlocked(server, ses_id);
        spin_unlock(&cifs_tcp_ses_lock);
 
+       return ses;
+}
+
+static struct cifs_tcon *
+smb2_find_smb_sess_tcon_unlocked(struct cifs_ses *ses, __u32  tid)
+{
+       struct cifs_tcon *tcon;
+
+       list_for_each_entry(tcon, &ses->tcon_list, tcon_list) {
+               if (tcon->tid != tid)
+                       continue;
+               ++tcon->tc_count;
+               return tcon;
+       }
+
        return NULL;
 }
 
+/*
+ * Obtain tcon corresponding to the tid in the given
+ * cifs_ses
+ */
+
+struct cifs_tcon *
+smb2_find_smb_tcon(struct TCP_Server_Info *server, __u64 ses_id, __u32 tid)
+{
+       struct cifs_ses *ses;
+       struct cifs_tcon *tcon;
+
+       spin_lock(&cifs_tcp_ses_lock);
+       ses = smb2_find_smb_ses_unlocked(server, ses_id);
+       if (!ses) {
+               spin_unlock(&cifs_tcp_ses_lock);
+               return NULL;
+       }
+       tcon = smb2_find_smb_sess_tcon_unlocked(ses, tid);
+       spin_unlock(&cifs_tcp_ses_lock);
+
+       return tcon;
+}
 
 int
 smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
@@ -143,7 +189,7 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
        struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
        struct cifs_ses *ses;
 
-       ses = smb2_find_smb_ses(smb2_pdu, server);
+       ses = smb2_find_smb_ses(server, smb2_pdu->SessionId);
        if (!ses) {
                cifs_dbg(VFS, "%s: Could not find session\n", __func__);
                return 0;
@@ -314,7 +360,7 @@ smb3_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server)
        struct smb2_hdr *smb2_pdu = (struct smb2_hdr *)iov[0].iov_base;
        struct cifs_ses *ses;
 
-       ses = smb2_find_smb_ses(smb2_pdu, server);
+       ses = smb2_find_smb_ses(server, smb2_pdu->SessionId);
        if (!ses) {
                cifs_dbg(VFS, "%s: Could not find session\n", __func__);
                return 0;

diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 66106f6ed7b4d65b96ab6459ee4d08b4f8829006..27dfb1e8aeaf4fe628f0a546226d8d48471bb01c 100644 (file)
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -784,9 +784,11 @@ SendReceive2(const unsigned int xid, struct cifs_ses *ses,
 
        rc = wait_for_response(ses->server, midQ);
        if (rc != 0) {
+               cifs_dbg(FYI, "Cancelling wait for mid %llu\n", midQ->mid);
                send_cancel(ses->server, buf, midQ);
                spin_lock(&GlobalMid_Lock);
                if (midQ->mid_state == MID_REQUEST_SUBMITTED) {
+                       midQ->mid_flags |= MID_WAIT_CANCELLED;
                        midQ->callback = DeleteMidQEntry;
                        spin_unlock(&GlobalMid_Lock);
                        cifs_small_buf_release(buf);