diff options
| -rw-r--r-- | include/net/tcp.h | 2 | ||||
| -rw-r--r-- | net/ipv4/syncookies.c | 25 | ||||
| -rw-r--r-- | net/ipv6/syncookies.c | 4 |
3 files changed, 22 insertions, 9 deletions
diff --git a/include/net/tcp.h b/include/net/tcp.h index 9e68e25c8b8..18c246c9b00 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -464,7 +464,7 @@ extern __u32 cookie_v4_init_sequence(struct sock *sk, struct sk_buff *skb, __u16 *mss); extern __u32 cookie_init_timestamp(struct request_sock *req); -extern void cookie_check_timestamp(struct tcp_options_received *tcp_opt); +extern bool cookie_check_timestamp(struct tcp_options_received *tcp_opt); /* From net/ipv6/syncookies.c */ extern struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb); diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 02bef6aa8b3..51b5662545d 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -230,23 +230,36 @@ static inline struct sock *get_cookie_sock(struct sock *sk, struct sk_buff *skb, * The lowest 4 bits are for snd_wscale * The next 4 lsb are for rcv_wscale * The next lsb is for sack_ok + * + * return false if we decode an option that should not be. */ -void cookie_check_timestamp(struct tcp_options_received *tcp_opt) +bool cookie_check_timestamp(struct tcp_options_received *tcp_opt) { /* echoed timestamp, 9 lowest bits contain options */ u32 options = tcp_opt->rcv_tsecr & TSMASK; + if (!tcp_opt->saw_tstamp) { + tcp_clear_options(tcp_opt); + return true; + } + + if (!sysctl_tcp_timestamps) + return false; + tcp_opt->snd_wscale = options & 0xf; options >>= 4; tcp_opt->rcv_wscale = options & 0xf; tcp_opt->sack_ok = (options >> 4) & 0x1; - if (tcp_opt->sack_ok) - tcp_sack_reset(tcp_opt); + if (tcp_opt->sack_ok && !sysctl_tcp_sack) + return false; - if (tcp_opt->snd_wscale || tcp_opt->rcv_wscale) + if (tcp_opt->snd_wscale || tcp_opt->rcv_wscale) { tcp_opt->wscale_ok = 1; + return sysctl_tcp_window_scaling != 0; + } + return true; } EXPORT_SYMBOL(cookie_check_timestamp); @@ -281,8 +294,8 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, memset(&tcp_opt, 0, sizeof(tcp_opt)); tcp_parse_options(skb, &tcp_opt, &hash_location, 0); - if (tcp_opt.saw_tstamp) - cookie_check_timestamp(&tcp_opt); + if (!cookie_check_timestamp(&tcp_opt)) + goto out; ret = NULL; req = inet_reqsk_alloc(&tcp_request_sock_ops); /* for safety */ diff --git a/net/ipv6/syncookies.c b/net/ipv6/syncookies.c index 70d330f8c99..c7ee57421ec 100644 --- a/net/ipv6/syncookies.c +++ b/net/ipv6/syncookies.c @@ -180,8 +180,8 @@ struct sock *cookie_v6_check(struct sock *sk, struct sk_buff *skb) memset(&tcp_opt, 0, sizeof(tcp_opt)); tcp_parse_options(skb, &tcp_opt, &hash_location, 0); - if (tcp_opt.saw_tstamp) - cookie_check_timestamp(&tcp_opt); + if (!cookie_check_timestamp(&tcp_opt)) + goto out; ret = NULL; req = inet6_reqsk_alloc(&tcp6_request_sock_ops); |