[PATCH 3.10 40/40] netfilter: Fix potential use after free in ip6_route_me_harder()

Greg Kroah-Hartman
2014-06-09T22:49:11Z

From: Sergey Popovich <popovich_sergei@mail.ru>

commit a8951d5814e1373807a94f79f7ccec7041325470 upstream.

Dst is released one line before we access it again with dst->error.

Fixes: 58e35d147128 netfilter: ipv6: propagate routing errors from
ip6_route_me_harder()

Signed-off-by: Sergey Popovich <popovich_sergei@mail.ru>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/ipv6/netfilter.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

--- a/net/ipv6/netfilter.c
+++ b/net/ipv6/netfilter.c
@@ -30,13 +30,15 @@ int ip6_route_me_harder(struct sk_buff *
.daddr = iph->daddr,
.saddr = iph->saddr,
};
+ int err;

dst = ip6_route_output(net, skb->sk, &fl6);
- if (dst->error) {
+ err = dst->error;
+ if (err) {
IP6_INC_STATS(net, ip6_dst_idev(dst), IPSTATS_MIB_OUTNOROUTES);
LIMIT_NETDEBUG(KERN_DEBUG "ip6_route_me_harder: No more route.\n");
dst_release(dst);
- return dst->error;
+ return err;
}

/* Drop old route. */