From: Steven J. Magnani <steve@digidescorp.com>
Date: Tue, 30 Mar 2010 20:56:01 +0000 (-0700)
Subject: net: Fix oops from tcp_collapse() when using splice()
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=baff42ab1494528907bf4d5870359e31711746ae;p=linux-beck.git

net: Fix oops from tcp_collapse() when using splice()

tcp_read_sock() can have a eat skbs without immediately advancing copied_seq.
This can cause a panic in tcp_collapse() if it is called as a result
of the recv_actor dropping the socket lock.

A userspace program that splices data from a socket to either another
socket or to a file can trigger this bug.

Signed-off-by: Steven J. Magnani <steve@digidescorp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 6afb6d8662b2..2c75f891914e 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1368,6 +1368,7 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc,
 		sk_eat_skb(sk, skb, 0);
 		if (!desc->count)
 			break;
+		tp->copied_seq = seq;
 	}
 	tp->copied_seq = seq;