The quilt patch titled
Subject: ocfs2: fix use-after-free when unmounting read-only filesystem
has been removed from the -mm tree. Its filename was
ocfs2-fix-use-after-free-when-unmounting-read-only-filesystem.patch
This patch was dropped because it was merged into the mm-hotfixes-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: LuÃs Henriques <ocfs2-devel@xxxxxxxxxxxxxx>
Subject: ocfs2: fix use-after-free when unmounting read-only filesystem
Date: Mon, 22 May 2023 11:21:12 +0100
It's trivial to trigger a use-after-free bug in the ocfs2 quotas code using
fstest generic/452. After a read-only remount, quotas are suspended and
ocfs2_mem_dqinfo is freed through ->ocfs2_local_free_info(). When unmounting
the filesystem, an UAF access to the oinfo will eventually cause a crash.
BUG: KASAN: slab-use-after-free in timer_delete+0x54/0xc0
Read of size 8 at addr ffff8880389a8208 by task umount/669
...
Call Trace:
<TASK>
...
timer_delete+0x54/0xc0
try_to_grab_pending+0x31/0x230
__cancel_work_timer+0x6c/0x270
ocfs2_disable_quotas.isra.0+0x3e/0xf0 [ocfs2]
ocfs2_dismount_volume+0xdd/0x450 [ocfs2]
generic_shutdown_super+0xaa/0x280
kill_block_super+0x46/0x70
deactivate_locked_super+0x4d/0xb0
cleanup_mnt+0x135/0x1f0
...
</TASK>
Allocated by task 632:
kasan_save_stack+0x1c/0x40
kasan_set_track+0x21/0x30
__kasan_kmalloc+0x8b/0x90
ocfs2_local_read_info+0xe3/0x9a0 [ocfs2]
dquot_load_quota_sb+0x34b/0x680
dquot_load_quota_inode+0xfe/0x1a0
ocfs2_enable_quotas+0x190/0x2f0 [ocfs2]
ocfs2_fill_super+0x14ef/0x2120 [ocfs2]
mount_bdev+0x1be/0x200
legacy_get_tree+0x6c/0xb0
vfs_get_tree+0x3e/0x110
path_mount+0xa90/0xe10
__x64_sys_mount+0x16f/0x1a0
do_syscall_64+0x43/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
Freed by task 650:
kasan_save_stack+0x1c/0x40
kasan_set_track+0x21/0x30
kasan_save_free_info+0x2a/0x50
__kasan_slab_free+0xf9/0x150
__kmem_cache_free+0x89/0x180
ocfs2_local_free_info+0x2ba/0x3f0 [ocfs2]
dquot_disable+0x35f/0xa70
ocfs2_susp_quotas.isra.0+0x159/0x1a0 [ocfs2]
ocfs2_remount+0x150/0x580 [ocfs2]
reconfigure_super+0x1a5/0x3a0
path_mount+0xc8a/0xe10
__x64_sys_mount+0x16f/0x1a0
do_syscall_64+0x43/0x90
entry_SYSCALL_64_after_hwframe+0x72/0xdc
Link: https://lkml.kernel.org/r/20230522102112.9031-1-lhenriques@xxxxxxx
Signed-off-by: LuÃs Henriques <lhenriques@xxxxxxx>
Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Tested-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Cc: Mark Fasheh <mark@xxxxxxxxxx>
Cc: Joel Becker <jlbec@xxxxxxxxxxxx>
Cc: Junxiao Bi <junxiao.bi@xxxxxxxxxx>
Cc: Changwei Ge <gechangwei@xxxxxxx>
Cc: Gang He <ghe@xxxxxxxx>
Cc: Jun Piao <piaojun@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/ocfs2/super.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/fs/ocfs2/super.c~ocfs2-fix-use-after-free-when-unmounting-read-only-filesystem
+++ a/fs/ocfs2/super.c
@@ -952,8 +952,10 @@ static void ocfs2_disable_quotas(struct
for (type = 0; type < OCFS2_MAXQUOTAS; type++) {
if (!sb_has_quota_loaded(sb, type))
continue;
- oinfo = sb_dqinfo(sb, type)->dqi_priv;
- cancel_delayed_work_sync(&oinfo->dqi_sync_work);
+ if (!sb_has_quota_suspended(sb, type)) {
+ oinfo = sb_dqinfo(sb, type)->dqi_priv;
+ cancel_delayed_work_sync(&oinfo->dqi_sync_work);
+ }
inode = igrab(sb->s_dquot.files[type]);
/* Turn off quotas. This will remove all dquot structures from
* memory and so they will be automatically synced to global
_
Patches currently in -mm which might be from ocfs2-devel@xxxxxxxxxxxxxx are
