icmp: Don't leak original dst into ip_route_input()

ip_route_input() unconditionally overwrites the dst. Hide the original
dst attached to the skb by calling skb_dst_set(skb, NULL) prior to
ip_route_input().

Reported-by: Julian Anastasov <[email protected]>
Signed-off-by: Thomas Graf <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
index f5203fba623638d94b03435db86ac4ed696adba8..c0556f1e4bf09233970c8d5c3fd68afa9a78489f 100644 (file)
--- a/net/ipv4/icmp.c
+++ b/net/ipv4/icmp.c
@@ -496,6 +496,7 @@ static struct rtable *icmp_route_lookup(struct net *net,
                }
                /* Ugh! */
                orefdst = skb_in->_skb_refdst; /* save old refdst */
+               skb_dst_set(skb_in, NULL);
                err = ip_route_input(skb_in, fl4_dec.daddr, fl4_dec.saddr,
                                     RT_TOS(tos), rt2->dst.dev);