This is a note to let you know that I've just added the patch titled
erofs: validate the extent length for uncompressed pclusters
to the 6.1-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-validate-the-extent-length-for-uncompressed-pc.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e28d9075ffb0486e3e0a8406b9033d34da6fc940
Author: Gao Xiang <xiang@xxxxxxxxxx>
Date: Mon Dec 5 23:00:50 2022 +0800
erofs: validate the extent length for uncompressed pclusters
[ Upstream commit c505feba4c0d76084e56ec498ce819f02a7043ae ]
syzkaller reported a KASAN use-after-free:
https://syzkaller.appspot.com/bug?extid=2ae90e873e97f1faf6f2
The referenced fuzzed image actually has two issues:
- m_pa == 0 as a non-inlined pcluster;
- The logical length is longer than its physical length.
The first issue has already been addressed. This patch addresses
the second issue by checking the extent length validity.
Reported-by: syzbot+2ae90e873e97f1faf6f2@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 02827e1796b3 ("staging: erofs: add erofs_map_blocks_iter")
Reviewed-by: Chao Yu <chao@xxxxxxxxxx>
Signed-off-by: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20221205150050.47784-2-hsiangkao@xxxxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/erofs/zmap.c b/fs/erofs/zmap.c
index f49295b9f2e1..e6d5d7a18fb0 100644
--- a/fs/erofs/zmap.c
+++ b/fs/erofs/zmap.c
@@ -698,6 +698,11 @@ static int z_erofs_do_map_blocks(struct inode *inode,
}
if (m.headtype == Z_EROFS_VLE_CLUSTER_TYPE_PLAIN) {
+ if (map->m_llen > map->m_plen) {
+ DBG_BUGON(1);
+ err = -EFSCORRUPTED;
+ goto unmap_out;
+ }
if (vi->z_advise & Z_EROFS_ADVISE_INTERLACED_PCLUSTER)
map->m_algorithmformat =
Z_EROFS_COMPRESSION_INTERLACED;
