From 2623939bfcab112d157fe7b11f213920824aa63b Mon Sep 17 00:00:00 2001 From: Arnaud Lecomte Date: Thu, 24 Apr 2025 00:13:51 +0200 Subject: [PATCH] jfs: upper bound check of tree index in dbAllocAG [ Upstream commit c214006856ff52a8ff17ed8da52d50601d54f9ce ] When computing the tree index in dbAllocAG, we never check if we are out of bounds realative to the size of the stree. This could happen in a scenario where the filesystem metadata are corrupted. Reported-by: syzbot+cffd18309153948f3c3e@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=cffd18309153948f3c3e Tested-by: syzbot+cffd18309153948f3c3e@syzkaller.appspotmail.com Signed-off-by: Arnaud Lecomte Signed-off-by: Dave Kleikamp Signed-off-by: Sasha Levin Signed-off-by: Ulrich Hecht --- 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 228864269f52..5f5f45202a2e 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -1470,6 +1470,12 @@ dbAllocAG(struct bmap * bmp, int agno, s64 nblocks, int l2nb, s64 * results) (1 << (L2LPERCTL - (bmp->db_agheight << 1))) / bmp->db_agwidth; ti = bmp->db_agstart + bmp->db_agwidth * (agno & (agperlev - 1)); + if (ti < 0 || ti >= le32_to_cpu(dcp->nleafs)) { + jfs_error(bmp->db_ipbmap->i_sb, "Corrupt dmapctl page\n"); + release_metapage(mp); + return -EIO; + } + /* dmap control page trees fan-out by 4 and a single allocation * group may be described by 1 or 2 subtrees within the ag level * dmap control page, depending upon the ag size. examine the ag's