From 525b861a008143048535011f3816d407940f4bfa Mon Sep 17 00:00:00 2001 From: Juntong Deng Date: Mon, 2 Oct 2023 17:56:58 +0800 Subject: fs/jfs: Add check for negative db_l2nbperpage 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: syzbot+debee9ab7ae2b34b0307@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=debee9ab7ae2b34b0307 Signed-off-by: Juntong Deng Signed-off-by: Dave Kleikamp --- fs/jfs/jfs_dmap.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/jfs') diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index 88afd108c2dd..3a1842348112 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -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; } -- cgit