From: Eric Dumazet <edumazet@google.com>
To: "David S . Miller" <davem@davemloft.net>
Cc: netdev <netdev@vger.kernel.org>,
Eric Dumazet <edumazet@google.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
syzbot <syzkaller@googlegroups.com>
Subject: [PATCH net] sch_netem: fix a divide by zero in tabledist()
Date: Wed, 18 Sep 2019 08:05:39 -0700 [thread overview]
Message-ID: <20190918150539.135042-1-edumazet@google.com> (raw)
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 <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
---
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 b17f2ed970e296adc57bed458ec3cced4fc6705b..f5cb35e550f8df557f2e444cc2fd142cab97789b 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -777,7 +777,7 @@ static int get_dist_table(struct Qdisc *sch, struct disttable **tbl,
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);
--
2.23.0.237.gc6a4ce50a0-goog
next reply other threads:[~2019-09-18 15:05 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-18 15:05 Eric Dumazet [this message]
2019-09-21 2:15 ` [PATCH net] sch_netem: fix a divide by zero in tabledist() Jakub Kicinski
2019-09-23 15:52 ` Eric Dumazet
2019-09-23 15:54 ` Eric Dumazet
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