From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Wed, 18 Sep 2019 23:24:12 +0000 (-0700)
Subject: net_sched: add max len check for TCA_KIND
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6f492e8010338dc2584a711b0cae388fd36120a5;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

net_sched: add max len check for TCA_KIND

[ Upstream commit 62794fc4fbf52f2209dc094ea255eaef760e7d01 ]

The TCA_KIND attribute is of NLA_STRING which does not check
the NUL char. KMSAN reported an uninit-value of TCA_KIND which
is likely caused by the lack of NUL.

Change it to NLA_NUL_STRING and add a max len too.

Fixes: 8b4c3cdd9dd8 ("net: sched: Add policy validation for tc attributes")
Reported-and-tested-by: syzbot+618aacd49e8c8b8486bd@syzkaller.appspotmail.com
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c
index 7b4270987ac1..637949b576c6 100644
--- a/net/sched/sch_api.c
+++ b/net/sched/sch_api.c
@@ -1217,7 +1217,8 @@ check_loop_fn(struct Qdisc *q, unsigned long cl, struct qdisc_walker *w)
  */
 
 const struct nla_policy rtm_tca_policy[TCA_MAX + 1] = {
-	[TCA_KIND]		= { .type = NLA_STRING },
+	[TCA_KIND]		= { .type = NLA_NUL_STRING,
+				    .len = IFNAMSIZ - 1 },
 	[TCA_RATE]		= { .type = NLA_BINARY,
 				    .len = sizeof(struct tc_estimator) },
 	[TCA_STAB]		= { .type = NLA_NESTED },