From 4957faade11b3a278c3b3cade3411ddc20afa791 Mon Sep 17 00:00:00 2001 From: William Allen Simpson Date: Wed, 2 Dec 2009 18:25:27 +0000 Subject: TCPCT part 1g: Responder Cookie => Initiator Parse incoming TCP_COOKIE option(s). Calculate TCP_COOKIE option. Send optional data. This is a significantly revised implementation of an earlier (year-old) patch that no longer applies cleanly, with permission of the original author (Adam Langley): http://thread.gmane.org/gmane.linux.network/102586 Requires: TCPCT part 1a: add request_values parameter for sending SYNACK TCPCT part 1b: generate Responder Cookie secret TCPCT part 1c: sysctl_tcp_cookie_size, socket option TCP_COOKIE_TRANSACTIONS TCPCT part 1d: define TCP cookie option, extend existing struct's TCPCT part 1e: implement socket option TCP_COOKIE_TRANSACTIONS TCPCT part 1f: Initiator Cookie => Responder Signed-off-by: William.Allen.Simpson@gmail.com Signed-off-by: David S. Miller --- net/ipv6/tcp_ipv6.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 50 insertions(+), 2 deletions(-) (limited to 'net/ipv6/tcp_ipv6.c') diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index f2ec38289a4a..fc0a4e5895ee 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1162,7 +1162,9 @@ static struct sock *tcp_v6_hnd_req(struct sock *sk,struct sk_buff *skb) */ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb) { + struct tcp_extend_values tmp_ext; struct tcp_options_received tmp_opt; + u8 *hash_location; struct request_sock *req; struct inet6_request_sock *treq; struct ipv6_pinfo *np = inet6_sk(sk); @@ -1206,8 +1208,52 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb) tcp_clear_options(&tmp_opt); tmp_opt.mss_clamp = IPV6_MIN_MTU - sizeof(struct tcphdr) - sizeof(struct ipv6hdr); tmp_opt.user_mss = tp->rx_opt.user_mss; + tcp_parse_options(skb, &tmp_opt, &hash_location, 0, dst); + + if (tmp_opt.cookie_plus > 0 && + tmp_opt.saw_tstamp && + !tp->rx_opt.cookie_out_never && + (sysctl_tcp_cookie_size > 0 || + (tp->cookie_values != NULL && + tp->cookie_values->cookie_desired > 0))) { + u8 *c; + u32 *d; + u32 *mess = &tmp_ext.cookie_bakery[COOKIE_DIGEST_WORDS]; + int l = tmp_opt.cookie_plus - TCPOLEN_COOKIE_BASE; + + if (tcp_cookie_generator(&tmp_ext.cookie_bakery[0]) != 0) + goto drop_and_free; + + /* Secret recipe starts with IP addresses */ + d = &ipv6_hdr(skb)->daddr.s6_addr32[0]; + *mess++ ^= *d++; + *mess++ ^= *d++; + *mess++ ^= *d++; + *mess++ ^= *d++; + d = &ipv6_hdr(skb)->saddr.s6_addr32[0]; + *mess++ ^= *d++; + *mess++ ^= *d++; + *mess++ ^= *d++; + *mess++ ^= *d++; + + /* plus variable length Initiator Cookie */ + c = (u8 *)mess; + while (l-- > 0) + *c++ ^= *hash_location++; - tcp_parse_options(skb, &tmp_opt, 0, dst); +#ifdef CONFIG_SYN_COOKIES + want_cookie = 0; /* not our kind of cookie */ +#endif + tmp_ext.cookie_out_never = 0; /* false */ + tmp_ext.cookie_plus = tmp_opt.cookie_plus; + } else if (!tp->rx_opt.cookie_in_always) { + /* redundant indications, but ensure initialization. */ + tmp_ext.cookie_out_never = 1; /* true */ + tmp_ext.cookie_plus = 0; + } else { + goto drop_and_free; + } + tmp_ext.cookie_in_always = tp->rx_opt.cookie_in_always; if (want_cookie && !tmp_opt.saw_tstamp) tcp_clear_options(&tmp_opt); @@ -1244,7 +1290,9 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb) security_inet_conn_request(sk, skb, req); - if (tcp_v6_send_synack(sk, req, NULL) || want_cookie) + if (tcp_v6_send_synack(sk, req, + (struct request_values *)&tmp_ext) || + want_cookie) goto drop_and_free; inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT); -- cgit v1.2.3-59-g8ed1b