[PATCH net] ipv6: do not leave garbage in rt->fib6_metrics

[Eric Dumazet]

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 <eduma...@google.com>
Reported-by: syzbot <syzkal...@googlegroups.com>
---
 net/ipv6/route.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 
6c1d817151cae45421dc976c5ea082b4115650be..74d97addf1af20dda0c2b6a2018e88696f9f7d5a
 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;
        }
 
-- 
2.19.0.605.g01d371f741-goog