From: Florian Westphal <fw@strlen.de>
Date: Fri, 20 Mar 2020 15:52:02 +0000 (+0100)
Subject: tcp: also NULL skb->dev when copy was needed
X-Git-Tag: v5.4.29~122
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c94b94626876b4c3885827e4f44498166a782c60;p=platform%2Fkernel%2Flinux-rpi.git

tcp: also NULL skb->dev when copy was needed

[ Upstream commit 07f8e4d0fddbf2f87e4cefb551278abc38db8cdd ]

In rare cases retransmit logic will make a full skb copy, which will not
trigger the zeroing added in recent change
b738a185beaa ("tcp: ensure skb->dev is NULL before leaving TCP stack").

Cc: Eric Dumazet <edumazet@google.com>
Fixes: 75c119afe14f ("tcp: implement rb-tree based retransmit queue")
Fixes: 28f8bfd1ac94 ("netfilter: Support iif matches in POSTROUTING")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 660b24f..196425f 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2976,8 +2976,12 @@ int __tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb, int segs)
 
 		tcp_skb_tsorted_save(skb) {
 			nskb = __pskb_copy(skb, MAX_TCP_HEADER, GFP_ATOMIC);
-			err = nskb ? tcp_transmit_skb(sk, nskb, 0, GFP_ATOMIC) :
-				     -ENOBUFS;
+			if (nskb) {
+				nskb->dev = NULL;
+				err = tcp_transmit_skb(sk, nskb, 0, GFP_ATOMIC);
+			} else {
+				err = -ENOBUFS;
+			}
 		} tcp_skb_tsorted_restore(skb);
 
 		if (!err) {