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 6c1d817..74d97ad 100644 (file)
--- 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;
        }