tcp: add server ip to encrypt cookie in fast open
Encrypt the cookie with both server and client IPv4 addresses,
such that multi-homed server will grant different cookies
based on both the source and destination IPs. No client change
is needed since cookie is opaque to the client.
Signed-off-by: Yuchung Cheng <ycheng@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 280efe5..ec27028 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1316,9 +1316,11 @@
tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
return true;
}
+
if (foc->len == TCP_FASTOPEN_COOKIE_SIZE) {
if ((sysctl_tcp_fastopen & TFO_SERVER_COOKIE_NOT_CHKED) == 0) {
- tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr, valid_foc);
+ tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr,
+ ip_hdr(skb)->daddr, valid_foc);
if ((valid_foc->len != TCP_FASTOPEN_COOKIE_SIZE) ||
memcmp(&foc->val[0], &valid_foc->val[0],
TCP_FASTOPEN_COOKIE_SIZE) != 0)
@@ -1329,14 +1331,16 @@
tcp_rsk(req)->rcv_nxt = TCP_SKB_CB(skb)->end_seq;
return true;
} else if (foc->len == 0) { /* Client requesting a cookie */
- tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr, valid_foc);
+ tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr,
+ ip_hdr(skb)->daddr, valid_foc);
NET_INC_STATS_BH(sock_net(sk),
LINUX_MIB_TCPFASTOPENCOOKIEREQD);
} else {
/* Client sent a cookie with wrong size. Treat it
* the same as invalid and return a valid one.
*/
- tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr, valid_foc);
+ tcp_fastopen_cookie_gen(ip_hdr(skb)->saddr,
+ ip_hdr(skb)->daddr, valid_foc);
}
return false;
}