[PATCH 3.10 004/123] ipv4: dst_entry leak in ip_send_unicast_reply()

From: Greg Kroah-Hartman
Date: Tue Nov 11 2014 - 20:49:44 EST


3.10-stable review patch. If anyone has any objections, please let me know.

------------------

From: Vasily Averin <vvs@xxxxxxxxxxxxx>

[ 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 <vvs@xxxxxxxxxxxxx>
Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/ip_output.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -1481,6 +1481,7 @@ void ip_send_unicast_reply(struct net *n
struct sk_buff *nskb;
struct sock *sk;
struct inet_sock *inet;
+ int err;

if (ip_options_echo(&replyopts.opt.opt, skb))
return;
@@ -1517,8 +1518,13 @@ void ip_send_unicast_reply(struct net *n
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)
@@ -1530,7 +1536,7 @@ void ip_send_unicast_reply(struct net *n
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);


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