From 149479d019e06df5a7f4096f95c00cfb1380309c Mon Sep 17 00:00:00 2001 From: Yuchung Cheng Date: Thu, 8 Aug 2013 14:06:22 -0700 Subject: [PATCH] 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 Reviewed-by: Eric Dumazet Acked-by: Neal Cardwell Signed-off-by: David S. Miller --- include/net/tcp.h | 3 ++- net/ipv4/tcp_fastopen.c | 13 ++++++------- net/ipv4/tcp_ipv4.c | 10 +++++++--- 3 files changed, 15 insertions(+), 11 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 27b652f379ef..09cb5c11ceea 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1300,7 +1300,8 @@ void tcp_free_fastopen_req(struct tcp_sock *tp); extern struct tcp_fastopen_context __rcu *tcp_fastopen_ctx; int tcp_fastopen_reset_cipher(void *key, unsigned int len); -void tcp_fastopen_cookie_gen(__be32 addr, struct tcp_fastopen_cookie *foc); +extern void tcp_fastopen_cookie_gen(__be32 src, __be32 dst, + struct tcp_fastopen_cookie *foc); #define TCP_FASTOPEN_KEY_LENGTH 16 diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c index 8f7ef0ad80e5..ab7bd35bb312 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -58,23 +58,22 @@ error: kfree(ctx); return err; } -/* Computes the fastopen cookie for the peer. - * The peer address is a 128 bits long (pad with zeros for IPv4). +/* Computes the fastopen cookie for the IP path. + * The path is a 128 bits long (pad with zeros for IPv4). * * The caller must check foc->len to determine if a valid cookie * has been generated successfully. */ -void tcp_fastopen_cookie_gen(__be32 addr, struct tcp_fastopen_cookie *foc) +void tcp_fastopen_cookie_gen(__be32 src, __be32 dst, + struct tcp_fastopen_cookie *foc) { - __be32 peer_addr[4] = { addr, 0, 0, 0 }; + __be32 path[4] = { src, dst, 0, 0 }; struct tcp_fastopen_context *ctx; rcu_read_lock(); ctx = rcu_dereference(tcp_fastopen_ctx); if (ctx) { - crypto_cipher_encrypt_one(ctx->tfm, - foc->val, - (__u8 *)peer_addr); + crypto_cipher_encrypt_one(ctx->tfm, foc->val, (__u8 *)path); foc->len = TCP_FASTOPEN_COOKIE_SIZE; } rcu_read_unlock(); diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 280efe5f19c1..ec2702882d8d 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1316,9 +1316,11 @@ static bool tcp_fastopen_check(struct sock *sk, struct sk_buff *skb, 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 @@ static bool tcp_fastopen_check(struct sock *sk, struct sk_buff *skb, 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; } -- 2.20.1