From: Juntong Deng juntong.deng@outlook.com

stable inclusion from stable-v5.10.202 commit c6c8863fb3f57700ab583d875adda04caaf2278a category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RG40 CVE: CVE-2023-52804

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

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[ Upstream commit 64933ab7b04881c6c18b21ff206c12278341c72e ]

Both db_maxag and db_agpref are used as the index of the db_agfree array, but there is currently no validity check for db_maxag and db_agpref, which can lead to errors.

The following is related bug reported by Syzbot:

UBSAN: array-index-out-of-bounds in fs/jfs/jfs_dmap.c:639:20 index 7936 is out of range for type 'atomic_t[128]'

Add checking that the values of db_maxag and db_agpref are valid indexes for the db_agfree array.

Reported-by: syzbot+38e876a8aa44b7115c76@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=38e876a8aa44b7115c76 Signed-off-by: Juntong Deng juntong.deng@outlook.com Signed-off-by: Dave Kleikamp dave.kleikamp@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Wang Hai wanghai38@huawei.com Signed-off-by: Yifan Qiao qiaoyifan4@huawei.com --- fs/jfs/jfs_dmap.c | 6 ++++++ 1 file changed, 6 insertions(+)

diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index b0a65aaed43e..2b749a7af316 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -188,6 +188,12 @@ int dbMount(struct inode *ipbmap) bmp->db_maxlevel = le32_to_cpu(dbmp_le->dn_maxlevel); bmp->db_maxag = le32_to_cpu(dbmp_le->dn_maxag); bmp->db_agpref = le32_to_cpu(dbmp_le->dn_agpref); + if (bmp->db_maxag >= MAXAG || bmp->db_maxag < 0 || + bmp->db_agpref >= MAXAG || bmp->db_agpref < 0) { + err = -EINVAL; + goto err_release_metapage; + } + bmp->db_aglevel = le32_to_cpu(dbmp_le->dn_aglevel); bmp->db_agheight = le32_to_cpu(dbmp_le->dn_agheight); bmp->db_agwidth = le32_to_cpu(dbmp_le->dn_agwidth);