Commit 5020785a authored by Juntong Deng's avatar Juntong Deng Committed by Li Nan
Browse files

fs/jfs: Add check for negative db_l2nbperpage 

stable inclusion
from stable-v5.10.202
commit 524b4f203afcf87accfe387e846f33f916f0c907
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RFEZ
CVE: CVE-2023-52810

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=524b4f203afcf87accfe387e846f33f916f0c907



--------------------------------

[ Upstream commit 525b861a008143048535011f3816d407940f4bfa ]

l2nbperpage is log2(number of blks per page), and the minimum legal
value should be 0, not negative.

In the case of l2nbperpage being negative, an error will occur
when subsequently used as shift exponent.

Syzbot reported this bug:

UBSAN: shift-out-of-bounds in fs/jfs/jfs_dmap.c:799:12
shift exponent -16777216 is negative

Reported-by: default avatar <syzbot+debee9ab7ae2b34b0307@syzkaller.appspotmail.com>
Closes: https://syzkaller.appspot.com/bug?extid=debee9ab7ae2b34b0307


Signed-off-by: default avatarJuntong Deng <juntong.deng@outlook.com>
Signed-off-by: default avatarDave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
Signed-off-by: default avatarsanglipeng <sanglipeng1@jd.com>
Signed-off-by: default avatarLi Nan <linan122@huawei.com>
parent 4292e6d5

fs/jfs/jfs_dmap.c

+2 −1
Original line number Diff line number Diff line
@@ -180,7 +180,8 @@ int dbMount(struct inode *ipbmap) 
	bmp->db_nfree = le64_to_cpu(dbmp_le->dn_nfree);



	bmp->db_l2nbperpage = le32_to_cpu(dbmp_le->dn_l2nbperpage);

	if (bmp->db_l2nbperpage > L2PSIZE - L2MINBLOCKSIZE) {

	if (bmp->db_l2nbperpage > L2PSIZE - L2MINBLOCKSIZE ||

		bmp->db_l2nbperpage < 0) {

		err = -EINVAL;

		goto err_release_metapage;

	}