From: Gao Xiang <hsiangkao@linux.alibaba.com>
Date: Tue, 11 Apr 2023 01:37:14 +0800
Subject: [PATCH] erofs: stop parsing non-compact HEAD index if clusterofs is
invalid
References: bsc#1012628
Patch-mainline: 6.3.2
Git-commit: cc4efd3dd2ac9f89143e5d881609747ecff04164
[ 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@google.com
Reported-and-tested-by: syzbot+aafb3f37cfeb6534c4ac@syzkaller.appspotmail.com
Fixes: 02827e1796b3 ("staging: erofs: add erofs_map_blocks_iter")
Fixes: 152a333a5895 ("staging: erofs: add compacted compression indexes support")
Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20230410173714.104604-1-hsiangkao@linux.alibaba.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
fs/erofs/zmap.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index 655da4d7..b5f40865 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -86,6 +86,10 @@ 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:
--
2.35.3