This is a note to let you know that I've just added the patch titled
erofs: stop parsing non-compact HEAD index if clusterofs is invalid
to the 6.2-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:
erofs-stop-parsing-non-compact-head-index-if-cluster.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4909f94d8a316ee0766c9effdeb8a43c2cbb91a0
Author: Gao Xiang <xiang@xxxxxxxxxx>
Date: Tue Apr 11 01:37:14 2023 +0800
erofs: stop parsing non-compact HEAD index if clusterofs is invalid
[ Upstream commit cc4efd3dd2ac9f89143e5d881609747ecff04164 ]
Syzbot generated a crafted image [1] with a non-compact HEAD index of
clusterofs 33024 while valid numbers should be 0 ~ lclustersize-1,
which causes the following unexpected behavior as below:
BUG: unable to handle page fault for address: fffff52101a3fff9
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 23ffed067 P4D 23ffed067 PUD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 4398 Comm: kworker/u5:1 Not tainted 6.3.0-rc6-syzkaller-g09a9639e56c0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
Workqueue: erofs_worker z_erofs_decompressqueue_work
RIP: 0010:z_erofs_decompress_queue+0xb7e/0x2b40
...
Call Trace:
<TASK>
z_erofs_decompressqueue_work+0x99/0xe0
process_one_work+0x8f6/0x1170
worker_thread+0xa63/0x1210
kthread+0x270/0x300
ret_from_fork+0x1f/0x30
Note that normal images or images using compact indexes are not
impacted. Let's fix this now.
[1] https://lore.kernel.org/r/000000000000ec75b005ee97fbaa@xxxxxxxxxx
Reported-and-tested-by: syzbot+aafb3f37cfeb6534c4ac@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 02827e1796b3 ("staging: erofs: add erofs_map_blocks_iter")
Fixes: 152a333a5895 ("staging: erofs: add compacted compression indexes support")
Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
Reviewed-by: Chao Yu <chao@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230410173714.104604-1-hsiangkao@xxxxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 98fb90b9af715..91733f8ecdffc 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -211,6 +211,10 @@ static int legacy_load_cluster_from_disk(struct z_erofs_maprecorder *m,
if (advise & Z_EROFS_VLE_DI_PARTIAL_REF)
m->partialref = true;
m->clusterofs = le16_to_cpu(di->di_clusterofs);
+ if (m->clusterofs >= 1 << vi->z_logical_clusterbits) {
+ DBG_BUGON(1);
+ return -EFSCORRUPTED;
+ }
m->pblk = le32_to_cpu(di->di_u.blkaddr);
break;
default:
