[091/117] net: Fix oops from tcp_collapse() when using splice()

From: Greg KH
Date: Mon May 10 2010 - 19:23:21 EST


2.6.33-stable review patch. If anyone has any objections, please let us know.

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


From: Steven J. Magnani <steve@xxxxxxxxxxxxxxx>

[ Upstream commit baff42ab1494528907bf4d5870359e31711746ae ]

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@xxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
net/ipv4/tcp.c | 1 +
1 file changed, 1 insertion(+)

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



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