This is a note to let you know that I've just added the patch titled
ext4: avoid hang when mounting non-journal filesystems with orphan list
to the 3.4-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-avoid-hang-when-mounting-non-journal-filesystems-with-orphan-list.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 0e9a9a1ad619e7e987815d20262d36a2f95717ca Mon Sep 17 00:00:00 2001
From: Theodore Ts'o <tytso@xxxxxxx>
Date: Thu, 27 Dec 2012 01:42:50 -0500
Subject: ext4: avoid hang when mounting non-journal filesystems with orphan list
From: Theodore Ts'o <tytso@xxxxxxx>
commit 0e9a9a1ad619e7e987815d20262d36a2f95717ca upstream.
When trying to mount a file system which does not contain a journal,
but which does have a orphan list containing an inode which needs to
be truncated, the mount call with hang forever in
ext4_orphan_cleanup() because ext4_orphan_del() will return
immediately without removing the inode from the orphan list, leading
to an uninterruptible loop in kernel code which will busy out one of
the CPU's on the system.
This can be trivially reproduced by trying to mount the file system
found in tests/f_orphan_extents_inode/image.gz from the e2fsprogs
source tree. If a malicious user were to put this on a USB stick, and
mount it on a Linux desktop which has automatic mounts enabled, this
could be considered a potential denial of service attack. (Not a big
deal in practice, but professional paranoids worry about such things,
and have even been known to allocate CVE numbers for such problems.)
-js: This is a fix for CVE-2013-2015.
Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
Reviewed-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
Acked-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/ext4/namei.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2054,7 +2054,8 @@ int ext4_orphan_del(handle_t *handle, st
int err = 0;
/* ext4_handle_valid() assumes a valid handle_t pointer */
- if (handle && !ext4_handle_valid(handle))
+ if (handle && !ext4_handle_valid(handle) &&
+ !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS))
return 0;
mutex_lock(&EXT4_SB(inode->i_sb)->s_orphan_lock);
Patches currently in stable-queue which might be from tytso@xxxxxxx are
queue-3.4/ext4-avoid-hang-when-mounting-non-journal-filesystems-with-orphan-list.patch
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