[2.6.22.2 review 50/84] eCryptfs: ecryptfs_setattr() bugfix

[Greg KH]

From: Michael Halcrow <mhalcrow@xxxxxxxxxx>

There is another bug recently introduced into the ecryptfs_setattr()
function in 2.6.22.  eCryptfs will attempt to treat special files like
regular eCryptfs files on chmod, chown, and so forth.  This leads to a NULL
pointer dereference.  This patch validates that the file is a regular file
before proceeding with operations related to the inode's crypt_stat.

Thanks to Ryusuke Konishi for finding this bug and suggesting the fix.

Signed-off-by: Michael Halcrow <mhalcrow@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 fs/ecryptfs/inode.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/fs/ecryptfs/inode.c
+++ b/fs/ecryptfs/inode.c
@@ -902,8 +902,9 @@ static int ecryptfs_setattr(struct dentr
 	mutex_lock(&crypt_stat->cs_mutex);
 	if (S_ISDIR(dentry->d_inode->i_mode))
 		crypt_stat->flags &= ~(ECRYPTFS_ENCRYPTED);
-	else if (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
-		 || !(crypt_stat->flags & ECRYPTFS_KEY_VALID)) {
+	else if (S_ISREG(dentry->d_inode->i_mode)
+		 && (!(crypt_stat->flags & ECRYPTFS_POLICY_APPLIED)
+		     || !(crypt_stat->flags & ECRYPTFS_KEY_VALID))) {
 		struct vfsmount *lower_mnt;
 		struct file *lower_file = NULL;
 		struct ecryptfs_mount_crypt_stat *mount_crypt_stat;

-- 
-
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