From: Eric Dumazet <edumazet@google.com>
Date: Fri, 5 Oct 2018 16:17:50 +0000 (-0700)
Subject: ipv6: do not leave garbage in rt->fib6_metrics
X-Git-Tag: v4.20-rc1~27^2~154
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=fda21d46cce2879dbce981978f8cb07b36035369;p=thirdparty%2Fkernel%2Flinux.git

ipv6: do not leave garbage in rt->fib6_metrics

In case ip_fib_metrics_init() returns an error, we better
rewrite rt->fib6_metrics with &dst_default_metrics so that
we do not crash later in ip_fib_metrics_put()

Fixes: 767a2217533f ("net: common metrics init helper for FIB entries")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 6c1d817151cae..74d97addf1af2 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -2976,6 +2976,8 @@ static struct fib6_info *ip6_route_info_create(struct fib6_config *cfg,
 	rt->fib6_metrics = ip_fib_metrics_init(net, cfg->fc_mx, cfg->fc_mx_len);
 	if (IS_ERR(rt->fib6_metrics)) {
 		err = PTR_ERR(rt->fib6_metrics);
+		/* Do not leave garbage there. */
+		rt->fib6_metrics = (struct dst_metrics *)&dst_default_metrics;
 		goto out;
 	}