From: Manas Ghandat <ghandatmanas@xxxxxxxxx> [ Upstream commit cca974daeb6c43ea971f8ceff5a7080d7d49ee30 ] Currently while joining the leaf in a buddy system there is shift out of bound error in calculation of BUDSIZE. Added the required check to the BUDSIZE and fixed the documentation as well. Reported-by: syzbot+411debe54d318eaed386@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://syzkaller.appspot.com/bug?extid=411debe54d318eaed386 Signed-off-by: Manas Ghandat <ghandatmanas@xxxxxxxxx> Signed-off-by: Dave Kleikamp <dave.kleikamp@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/jfs/jfs_dmap.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index 893bc59658da..0cfdd52021f1 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -2840,7 +2840,9 @@ static int dbBackSplit(dmtree_t *tp, int leafno, bool is_ctl) * leafno - the number of the leaf to be updated. * newval - the new value for the leaf. * - * RETURN VALUES: none + * RETURN VALUES: + * 0 - success + * -EIO - i/o error */ static int dbJoin(dmtree_t *tp, int leafno, int newval, bool is_ctl) { @@ -2867,6 +2869,10 @@ static int dbJoin(dmtree_t *tp, int leafno, int newval, bool is_ctl) * get the buddy size (number of words covered) of * the new value. */ + + if ((newval - tp->dmt_budmin) > BUDMIN) + return -EIO; + budsz = BUDSIZE(newval, tp->dmt_budmin); /* try to join. -- 2.43.0
