aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorEric Dumazet <edumazet@google.com>2012-11-13 05:37:18 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-01-11 09:03:48 -0800
commitffd34fcbce326a88668075b9e5480cb301ac6a78 (patch)
treea6828391b644055ea5cfcb0c1959d2b17c7dc0c7
parent282190eab6442da4789ae3c3037c7b19d65eaf52 (diff)
downloadkernel_samsung_smdk4412-ffd34fcbce326a88668075b9e5480cb301ac6a78.zip
kernel_samsung_smdk4412-ffd34fcbce326a88668075b9e5480cb301ac6a78.tar.gz
kernel_samsung_smdk4412-ffd34fcbce326a88668075b9e5480cb301ac6a78.tar.bz2
tcp: tcp_replace_ts_recent() should not be called from tcp_validate_incoming()
[ Upstream commit bd090dfc634ddd711a5fbd0cadc6e0ab4977bcaf ] We added support for RFC 5961 in latest kernels but TCP fails to perform exhaustive check of ACK sequence. We can update our view of peer tsval from a frame that is later discarded by tcp_ack() This makes timestamps enabled sessions vulnerable to injection of a high tsval : peers start an ACK storm, since the victim sends a dupack each time it receives an ACK from the other peer. As tcp_validate_incoming() is called before tcp_ack(), we should not peform tcp_replace_ts_recent() from it, and let callers do it at the right time. Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: H.K. Jerry Chu <hkchu@google.com> Cc: Romain Francoise <romain@orebokech.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/ipv4/tcp_input.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 2598822..ab564f6 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -5237,11 +5237,6 @@ static bool tcp_validate_incoming(struct sock *sk, struct sk_buff *skb,
goto discard;
}
- /* ts_recent update must be made after we are sure that the packet
- * is in window.
- */
- tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
-
/* step 3: check security and precedence [ignored] */
/* step 4: Check for a SYN
@@ -5476,6 +5471,11 @@ step5:
if (th->ack && tcp_ack(sk, skb, FLAG_SLOWPATH) < 0)
goto discard;
+ /* ts_recent update must be made after we are sure that the packet
+ * is in window.
+ */
+ tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
+
tcp_rcv_rtt_measure_ts(sk, skb);
/* Process urgent data. */
@@ -5952,6 +5952,11 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb,
} else
goto discard;
+ /* ts_recent update must be made after we are sure that the packet
+ * is in window.
+ */
+ tcp_replace_ts_recent(tp, TCP_SKB_CB(skb)->seq);
+
/* step 6: check the URG bit */
tcp_urg(sk, skb, th);