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Subject[146/156] tcp: Fix tcp_make_synack()
2.6.33-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Eric Dumazet <eric.dumazet@gmail.com>

[ Upstream commit 28b2774a0d5852236dab77a4147b8b88548110f1 ]

Commit 4957faad (TCPCT part 1g: Responder Cookie => Initiator), part
of TCP_COOKIE_TRANSACTION implementation, forgot to correctly size
synack skb in case user data must be included.

Many thanks to Mika Pentillä for spotting this error.

Reported-by: Penttillä Mika <mika.penttila@ixonos.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
net/ipv4/tcp_output.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2393,13 +2393,17 @@ struct sk_buff *tcp_make_synack(struct s
struct tcp_extend_values *xvp = tcp_xv(rvp);
struct inet_request_sock *ireq = inet_rsk(req);
struct tcp_sock *tp = tcp_sk(sk);
+ const struct tcp_cookie_values *cvp = tp->cookie_values;
struct tcphdr *th;
struct sk_buff *skb;
struct tcp_md5sig_key *md5;
int tcp_header_size;
int mss;
+ int s_data_desired = 0;

- skb = sock_wmalloc(sk, MAX_TCP_HEADER + 15, 1, GFP_ATOMIC);
+ if (cvp != NULL && cvp->s_data_constant && cvp->s_data_desired)
+ s_data_desired = cvp->s_data_desired;
+ skb = sock_wmalloc(sk, MAX_TCP_HEADER + 15 + s_data_desired, 1, GFP_ATOMIC);
if (skb == NULL)
return NULL;

@@ -2454,16 +2458,12 @@ struct sk_buff *tcp_make_synack(struct s
TCPCB_FLAG_SYN | TCPCB_FLAG_ACK);

if (OPTION_COOKIE_EXTENSION & opts.options) {
- const struct tcp_cookie_values *cvp = tp->cookie_values;
-
- if (cvp != NULL &&
- cvp->s_data_constant &&
- cvp->s_data_desired > 0) {
- u8 *buf = skb_put(skb, cvp->s_data_desired);
+ if (s_data_desired) {
+ u8 *buf = skb_put(skb, s_data_desired);

/* copy data directly from the listening socket. */
- memcpy(buf, cvp->s_data_payload, cvp->s_data_desired);
- TCP_SKB_CB(skb)->end_seq += cvp->s_data_desired;
+ memcpy(buf, cvp->s_data_payload, s_data_desired);
+ TCP_SKB_CB(skb)->end_seq += s_data_desired;
}

if (opts.hash_size > 0) {

--
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