From: Vasily Averin Date: Wed, 15 Oct 2014 12:24:02 +0000 (+0400) Subject: ipv4: dst_entry leak in ip_send_unicast_reply() X-Git-Tag: v3.12.33~193 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d84c3df2a5f2e6847a15c5d7fbdfba86346e67ab;p=thirdparty%2Fkernel%2Fstable.git ipv4: dst_entry leak in ip_send_unicast_reply() [ Upstream commit 4062090e3e5caaf55bed4523a69f26c3265cc1d2 ] ip_setup_cork() called inside ip_append_data() steals dst entry from rt to cork and in case errors in __ip_append_data() nobody frees stolen dst entry Fixes: 2e77d89b2fa8 ("net: avoid a pair of dst_hold()/dst_release() in ip_append_data()") Signed-off-by: Vasily Averin Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index c1cb9475fadf0..c2dcee28d0714 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -1478,6 +1478,7 @@ void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr, struct sk_buff *nskb; struct sock *sk; struct inet_sock *inet; + int err; if (ip_options_echo(&replyopts.opt.opt, skb)) return; @@ -1514,8 +1515,13 @@ void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr, sock_net_set(sk, net); __skb_queue_head_init(&sk->sk_write_queue); sk->sk_sndbuf = sysctl_wmem_default; - ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base, len, 0, - &ipc, &rt, MSG_DONTWAIT); + err = ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base, + len, 0, &ipc, &rt, MSG_DONTWAIT); + if (unlikely(err)) { + ip_flush_pending_frames(sk); + goto out; + } + nskb = skb_peek(&sk->sk_write_queue); if (nskb) { if (arg->csumoffset >= 0) @@ -1527,7 +1533,7 @@ void ip_send_unicast_reply(struct net *net, struct sk_buff *skb, __be32 daddr, skb_set_queue_mapping(nskb, skb_get_queue_mapping(skb)); ip_push_pending_frames(sk, &fl4); } - +out: put_cpu_var(unicast_sock); ip_rt_put(rt);