Patch "ext4 crypto: use dget_parent() in ext4_d_revalidate()" has been added to the 4.5-stable tree

Patch "ext4 crypto: use dget_parent() in ext4_d_revalidate()" has been added to the 4.5-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ext4 crypto: use dget_parent() in ext4_d_revalidate()

to the 4.5-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ext4-crypto-use-dget_parent-in-ext4_d_revalidate.patch
and it can be found in the queue-4.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 3d43bcfef5f0548845a425365011c499875491b0 Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@mit.edu>
Date: Sat, 26 Mar 2016 16:15:42 -0400
Subject: ext4 crypto: use dget_parent() in ext4_d_revalidate()

From: Theodore Ts'o <tytso@mit.edu>

commit 3d43bcfef5f0548845a425365011c499875491b0 upstream.

This avoids potential problems caused by a race where the inode gets
renamed out from its parent directory and the parent directory is
deleted while ext4_d_revalidate() is running.

Fixes: 28b4c263961c
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/ext4/crypto.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -475,13 +475,16 @@ uint32_t ext4_validate_encryption_key_si
  */
 static int ext4_d_revalidate(struct dentry *dentry, unsigned int flags)
 {
-	struct inode *dir = d_inode(dentry->d_parent);
-	struct ext4_crypt_info *ci = EXT4_I(dir)->i_crypt_info;
+	struct dentry *dir;
+	struct ext4_crypt_info *ci;
 	int dir_has_key, cached_with_key;
 
-	if (!ext4_encrypted_inode(dir))
+	dir = dget_parent(dentry);
+	if (!ext4_encrypted_inode(d_inode(dir))) {
+		dput(dir);
 		return 0;
-
+	}
+	ci = EXT4_I(d_inode(dir))->i_crypt_info;
 	if (ci && ci->ci_keyring_key &&
 	    (ci->ci_keyring_key->flags & ((1 << KEY_FLAG_INVALIDATED) |
 					  (1 << KEY_FLAG_REVOKED) |
@@ -491,6 +494,7 @@ static int ext4_d_revalidate(struct dent
 	/* this should eventually be an flag in d_flags */
 	cached_with_key = dentry->d_fsdata != NULL;
 	dir_has_key = (ci != NULL);
+	dput(dir);
 
 	/*
 	 * If the dentry was cached without the key, and it is a


Patches currently in stable-queue which might be from tytso@mit.edu are

queue-4.5/ext4-use-dget_parent-in-ext4_file_open.patch
queue-4.5/ext4-add-lockdep-annotations-for-i_data_sem.patch
queue-4.5/ext4-use-file_dentry.patch
queue-4.5/ext4-ignore-quota-mount-options-if-the-quota-feature-is-enabled.patch
queue-4.5/nfs-use-file_dentry.patch
queue-4.5/ext4-crypto-use-dget_parent-in-ext4_d_revalidate.patch
queue-4.5/fs-add-file_dentry.patch