This is a note to let you know that I've just added the patch titled
ext4: fix use-after-iput when fscrypt contexts are inconsistent
to the 4.9-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-fix-use-after-iput-when-fscrypt-contexts-are-inconsistent.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From dd01b690f8f4b1e414f89e5a9a5326bf720d6652 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@xxxxxxxxxx>
Date: Wed, 1 Feb 2017 21:07:11 -0500
Subject: ext4: fix use-after-iput when fscrypt contexts are inconsistent
From: Eric Biggers <ebiggers@xxxxxxxxxx>
commit dd01b690f8f4b1e414f89e5a9a5326bf720d6652 upstream.
In the case where the child's encryption context was inconsistent with
its parent directory, we were using inode->i_sb and inode->i_ino after
the inode had already been iput(). Fix this by doing the iput() in the
correct places.
Note: only ext4 had this bug, not f2fs and ubifs.
Fixes: d9cdc9033181 ("ext4 crypto: enforce context consistency")
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/namei.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1616,13 +1616,15 @@ static struct dentry *ext4_lookup(struct
!fscrypt_has_permitted_context(dir, inode)) {
int nokey = ext4_encrypted_inode(inode) &&
!fscrypt_has_encryption_key(inode);
- iput(inode);
- if (nokey)
+ if (nokey) {
+ iput(inode);
return ERR_PTR(-ENOKEY);
+ }
ext4_warning(inode->i_sb,
"Inconsistent encryption contexts: %lu/%lu",
(unsigned long) dir->i_ino,
(unsigned long) inode->i_ino);
+ iput(inode);
return ERR_PTR(-EPERM);
}
}
Patches currently in stable-queue which might be from ebiggers@xxxxxxxxxx are
queue-4.9/ext4-fix-use-after-iput-when-fscrypt-contexts-are-inconsistent.patch