From b443d4bb439dc1fe40f3fb4cd65a01eb905a7557 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 18 Sep 2019 08:05:39 -0700 Subject: [PATCH] sch_netem: fix a divide by zero in tabledist() [ Upstream commit b41d936b5ecfdb3a4abc525ce6402a6c49cffddc ] syzbot managed to crash the kernel in tabledist() loading an empty distribution table. t = dist->table[rnd % dist->size]; Simply return an error when such load is attempted. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/sched/sch_netem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c index 3d5654333d49..787aa52e5991 100644 --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -708,7 +708,7 @@ static int get_dist_table(struct Qdisc *sch, const struct nlattr *attr) struct disttable *d; int i; - if (n > NETEM_DIST_MAX) + if (!n || n > NETEM_DIST_MAX) return -EINVAL; d = kvmalloc(sizeof(struct disttable) + n * sizeof(s16), GFP_KERNEL); -- 2.20.1