From: Juntong Deng Date: Mon, 2 Oct 2023 09:56:58 +0000 (+0800) Subject: fs/jfs: Add check for negative db_l2nbperpage X-Git-Tag: v6.1.68~695 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0cb567e727339a192f9fd0db00781d73a91d15a6;p=platform%2Fkernel%2Flinux-starfive.git fs/jfs: Add check for negative db_l2nbperpage [ 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: syzbot+debee9ab7ae2b34b0307@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=debee9ab7ae2b34b0307 Signed-off-by: Juntong Deng Signed-off-by: Dave Kleikamp Signed-off-by: Sasha Levin --- diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index e9d075c..ee949e3 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; }