[PATCH] TCP: Fix sorting of SACK blocks.

The sorting of SACK blocks actually munges them rather than sort,
causing the TCP stack to ignore some SACK information and breaking the
assumption of ordered SACK blocks after sorting.

The sort takes the data from a second buffer which isn't moved causing
subsequent data moves to occur from the wrong location. The fix is to
use a temporary buffer as a normal sort does.

Signed-off-By: Baruch Even <baruch@ev-en.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index cf06accbe687a96a21bf5098163b4c8ddb662818..026ef8f690feafc48e9da64861d66d4221dfc110 100644 (file)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1011,10 +1011,11 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
                        for (j = 0; j < i; j++){
                                if (after(ntohl(sp[j].start_seq),
                                          ntohl(sp[j+1].start_seq))){
-                                       sp[j].start_seq = htonl(tp->recv_sack_cache[j+1].start_seq);
-                                       sp[j].end_seq = htonl(tp->recv_sack_cache[j+1].end_seq);
-                                       sp[j+1].start_seq = htonl(tp->recv_sack_cache[j].start_seq);
-                                       sp[j+1].end_seq = htonl(tp->recv_sack_cache[j].end_seq);
+                                       struct tcp_sack_block_wire tmp;
+
+                                       tmp = sp[j];
+                                       sp[j] = sp[j+1];
+                                       sp[j+1] = tmp;
                                }
 
                        }