4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Theodore Ts'o <ty...@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 <v...@zeniv.linux.org.uk>
Signed-off-by: Theodore Ts'o <ty...@mit.edu>
Signed-off-by: Eric Biggers <ebigg...@google.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
fs/ext4/crypto.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -477,16 +477,21 @@ 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;
/* 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
