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ipv4: dst_entry leak in ip_send_unicast_reply()

PATCH In review Vasily Averin 3 participants 4 messages Oct 15, 2014 – Oct 17, 2014

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Networking Network drivers IPv4/IPv6
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Vasily Averin

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#0 lore raw

PATCH 1/1 ipv4: dst_entry leak in ip_send_unicast_reply()

Fixes 2e77d89b2fa8 ("net: avoid a pair of dst_hold()/dst_release() in ip_append_data()")

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

Signed-off-by Vasily Averin <[email protected]>
---
 net/ipv4/ip_output.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)
net/ipv4/ip_output.c +9 -3
index e35b712..88e5ef2 100644
@@ -1535,6 +1535,7 @@ void ip_send_unicast_reply(struct net *net, struct sk_buff *skb,
 	struct sk_buff *nskb;
 	struct sock *sk;
 	struct inet_sock *inet;
+	int err;
 
 	if (__ip_options_echo(&replyopts.opt.opt, skb, sopt))
 		return;

@@ -1574,8 +1575,13 @@ void ip_send_unicast_reply(struct net *net, struct sk_buff *skb,
 	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)

@@ -1587,7 +1593,7 @@ void ip_send_unicast_reply(struct net *net, struct sk_buff *skb,
 		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);
Signature · 1 line
1.9.1
maintainer
#1 lore raw

From: Vasily Averin <[email protected]>
Date: Wed, 15 Oct 2014 16:24:02 +0400

Quoted 6 lines
Fixes 2e77d89b2fa8 ("net: avoid a pair of dst_hold()/dst_release() in ip_append_data()")

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

Signed-off-by Vasily Averin <[email protected]>

Please, in the future, put the Fixes: tag first in the list of signoffs.

Eric, please review this change, it looks good to me.

Acked-by
#2 lore raw
Quoted 5 lines · David Miller

From: Vasily Averin <[email protected]>
Date: Wed, 15 Oct 2014 16:24:02 +0400

Quoted 2 lines
Fixes 2e77d89b2fa8 ("net: avoid a pair of dst_hold()/dst_release() in ip_append_data()")
Quoted 8 lines
Quoted 4 lines

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

Signed-off-by Vasily Averin <[email protected]>

Please, in the future, put the Fixes: tag first in the list of signoffs.

Eric, please review this change, it looks good to me.

It is good indeed, thanks !

Acked-by Eric Dumazet <[email protected]>
maintainer
#3 lore raw
In reply to Vasily Averin

From: Vasily Averin <[email protected]>
Date: Wed, 15 Oct 2014 16:24:02 +0400

Quoted 6 lines
Fixes 2e77d89b2fa8 ("net: avoid a pair of dst_hold()/dst_release() in ip_append_data()")

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

Signed-off-by Vasily Averin <[email protected]>

Applied and queued up for -stable, thanks everyone!