From 4a269818a7eb8577d32d8b2879099c689ddbd856 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet@google.com>
Date: Wed, 11 Oct 2017 13:27:29 -0700
Subject: [PATCH] tcp: fix tcp_unlink_write_queue()
Yury reported crash with this signature :
[ 554.034021] [<ffff80003ccd5a58>] 0xffff80003ccd5a58
[ 554.034156] [<ffff00000888fd34>] skb_release_all+0x14/0x30
[ 554.034288] [<ffff00000888fd64>] __kfree_skb+0x14/0x28
[ 554.034409] [<ffff0000088ece6c>] tcp_sendmsg_locked+0x4dc/0xcc8
[ 554.034541] [<ffff0000088ed68c>] tcp_sendmsg+0x34/0x58
[ 554.034659] [<ffff000008919fd4>] inet_sendmsg+0x2c/0xf8
[ 554.034783] [<ffff0000088842e8>] sock_sendmsg+0x18/0x30
[ 554.034928] [<ffff0000088861fc>] SyS_sendto+0x84/0xf8
Problem is that skb->destructor contains garbage, and this is
because I accidentally removed tcp_skb_tsorted_anchor_cleanup()
from tcp_unlink_write_queue()
This would trigger with a write(fd, <invalid_memory>, len) attempt,
and we will add to packetdrill this capability to avoid future
regressions.
Fixes: 75c119afe14f ("tcp: implement rb-tree based retransmit queue")
Reported-by: Yury Norov <ynorov@caviumnetworks.com>
Tested-by: Yury Norov <ynorov@caviumnetworks.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
include/net/tcp.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 5a95e5886b55e..15163454174ba 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1712,6 +1712,7 @@ static inline void tcp_insert_write_queue_before(struct sk_buff *new,
static inline void tcp_unlink_write_queue(struct sk_buff *skb, struct sock *sk)
{
+ tcp_skb_tsorted_anchor_cleanup(skb);
__skb_unlink(skb, &sk->sk_write_queue);
}
--
2.30.2