reiserfs: preserve i_mode if __reiserfs_set_acl() fails

commit fcea8aed91f53b51f9b943dc01f12d8aa666c720 upstream.

When changing a file's acl mask, reiserfs_set_acl() will first set the
group bits of i_mode to the value of the mask, and only then set the
actual extended attribute representing the new acl.

If the second part fails (due to lack of space, for example) and the
file had no acl attribute to begin with, the system will from now on
assume that the mask permission bits are actual group permission bits,
potentially granting access to the wrong users.

Prevent this by only changing the inode mode after the acl has been set.

Signed-off-by: Ernesto A. Fernández <ernesto.mnd.fernandez@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/reiserfs/xattr_acl.c b/fs/reiserfs/xattr_acl.c
index fa77347f4a3421f5701ec7af8c3093645d8a8cc3..095d0a52e5a657dfe00d6fa1cdf5f138da8e6c86 100644 (file)
--- a/fs/reiserfs/xattr_acl.c
+++ b/fs/reiserfs/xattr_acl.c
@@ -23,7 +23,8 @@ reiserfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
        struct reiserfs_transaction_handle th;
        size_t jcreate_blocks;
        int size = acl ? posix_acl_xattr_size(acl->a_count) : 0;
-
+       int update_mode = 0;
+       umode_t mode = inode->i_mode;
 
        /*
         * Pessimism: We can't assume that anything from the xattr root up
@@ -38,12 +39,14 @@ reiserfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
        reiserfs_write_unlock(inode->i_sb);
        if (error == 0) {
                if (type == ACL_TYPE_ACCESS && acl) {
-                       error = posix_acl_update_mode(inode, &inode->i_mode,
-                                                     &acl);
+                       error = posix_acl_update_mode(inode, &mode, &acl);
                        if (error)
                                goto unlock;
+                       update_mode = 1;
                }
                error = __reiserfs_set_acl(&th, inode, type, acl);
+               if (!error && update_mode)
+                       inode->i_mode = mode;
 unlock:
                reiserfs_write_lock(inode->i_sb);
                error2 = journal_end(&th);