Introduce a helper that: (1) shares the common code with TCP-MD5 header options parsing (2) looks for hash signature only once for both TCP-MD5 and TCP-AO (3) fails with -EEXIST if any TCP sign option is present twice, see RFC5925 (2.2): ">> A single TCP segment MUST NOT have more than one TCP-AO in its options sequence. When multiple TCP-AOs appear, TCP MUST discard the segment." Co-developed-by: Francesco Ruggeri <fruggeri@xxxxxxxxxx> Signed-off-by: Francesco Ruggeri <fruggeri@xxxxxxxxxx> Co-developed-by: Salam Noureddine <noureddine@xxxxxxxxxx> Signed-off-by: Salam Noureddine <noureddine@xxxxxxxxxx> Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx> --- include/net/tcp.h | 24 +++++++++++++++++++++++- include/net/tcp_ao.h | 3 +++ net/ipv4/tcp.c | 3 ++- net/ipv4/tcp_input.c | 39 +++++++++++++++++++++++++++++---------- net/ipv4/tcp_ipv4.c | 21 ++++++++++++++------- net/ipv6/tcp_ipv6.c | 17 +++++++++++------ 6 files changed, 82 insertions(+), 25 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index d91a963f430d..061fe8471bfc 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -428,7 +428,6 @@ int tcp_mmap(struct file *file, struct socket *sock, void tcp_parse_options(const struct net *net, const struct sk_buff *skb, struct tcp_options_received *opt_rx, int estab, struct tcp_fastopen_cookie *foc); -const u8 *tcp_parse_md5sig_option(const struct tcphdr *th); /* * BPF SKB-less helpers @@ -2467,4 +2466,27 @@ static inline u64 tcp_transmit_time(const struct sock *sk) return 0; } +static inline int tcp_parse_auth_options(const struct tcphdr *th, + const u8 **md5_hash, const struct tcp_ao_hdr **aoh) +{ + const u8 *md5_tmp, *ao_tmp; + int ret; + + ret = tcp_do_parse_auth_options(th, &md5_tmp, &ao_tmp); + if (ret) + return ret; + + if (md5_hash) + *md5_hash = md5_tmp; + + if (aoh) { + if (!ao_tmp) + *aoh = NULL; + else + *aoh = (struct tcp_ao_hdr *)(ao_tmp - 2); + } + + return 0; +} + #endif /* _TCP_H */ diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h index f840b693d038..b5516c83e489 100644 --- a/include/net/tcp_ao.h +++ b/include/net/tcp_ao.h @@ -87,6 +87,9 @@ struct tcp_ao_info { u32 rcv_sne_seq; }; +int tcp_do_parse_auth_options(const struct tcphdr *th, + const u8 **md5_hash, const u8 **ao_hash); + #ifdef CONFIG_TCP_AO /* TCP-AO structures and functions */ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 85854b8afc47..a5e94d8e8450 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4526,7 +4526,8 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, l3index = sdif ? dif : 0; hash_expected = tcp_md5_do_lookup(sk, l3index, saddr, family); - hash_location = tcp_parse_md5sig_option(th); + if (tcp_parse_auth_options(th, &hash_location, NULL)) + return true; /* We've parsed the options - do we have a hash? */ if (!hash_expected && !hash_location) diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index a5d6c7f1ead3..27e95876cba1 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4188,39 +4188,58 @@ static bool tcp_fast_parse_options(const struct net *net, return true; } -#ifdef CONFIG_TCP_MD5SIG +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) /* - * Parse MD5 Signature option + * Parse Signature options */ -const u8 *tcp_parse_md5sig_option(const struct tcphdr *th) +int tcp_do_parse_auth_options(const struct tcphdr *th, + const u8 **md5_hash, const u8 **ao_hash) { int length = (th->doff << 2) - sizeof(*th); const u8 *ptr = (const u8 *)(th + 1); + unsigned int minlen = TCPOLEN_MD5SIG; + + if (IS_ENABLED(CONFIG_TCP_AO)) + minlen = sizeof(struct tcp_ao_hdr) + 1; + + *md5_hash = NULL; + *ao_hash = NULL; /* If not enough data remaining, we can short cut */ - while (length >= TCPOLEN_MD5SIG) { + while (length >= minlen) { int opcode = *ptr++; int opsize; switch (opcode) { case TCPOPT_EOL: - return NULL; + return 0; case TCPOPT_NOP: length--; continue; default: opsize = *ptr++; if (opsize < 2 || opsize > length) - return NULL; - if (opcode == TCPOPT_MD5SIG) - return opsize == TCPOLEN_MD5SIG ? ptr : NULL; + return -EINVAL; + if (opcode == TCPOPT_MD5SIG) { + if (opsize != TCPOLEN_MD5SIG) + return -EINVAL; + if (unlikely(*md5_hash || *ao_hash)) + return -EEXIST; + *md5_hash = ptr; + } else if (opcode == TCPOPT_AO) { + if (opsize <= sizeof(struct tcp_ao_hdr)) + return -EINVAL; + if (unlikely(*md5_hash || *ao_hash)) + return -EEXIST; + *ao_hash = ptr; + } } ptr += opsize - 2; length -= opsize; } - return NULL; + return 0; } -EXPORT_SYMBOL(tcp_parse_md5sig_option); +EXPORT_SYMBOL(tcp_do_parse_auth_options); #endif /* Sorry, PAWS as specified is broken wrt. pure-ACKs -DaveM diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index f6fe9ec1c99d..034549c73beb 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -660,7 +660,9 @@ EXPORT_SYMBOL(tcp_v4_send_check); * Exception: precedence violation. We do not implement it in any case. */ -#ifdef CONFIG_TCP_MD5SIG +#ifdef CONFIG_TCP_AO +#define OPTION_BYTES MAX_TCP_OPTION_SPACE +#elif CONFIG_TCP_MD5SIG #define OPTION_BYTES TCPOLEN_MD5SIG_ALIGNED #else #define OPTION_BYTES sizeof(__be32) @@ -676,7 +678,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) struct ip_reply_arg arg; #ifdef CONFIG_TCP_MD5SIG struct tcp_md5sig_key *key = NULL; - const __u8 *hash_location = NULL; + const __u8 *md5_hash_location = NULL; unsigned char newhash[16]; int genhash; struct sock *sk1 = NULL; @@ -715,9 +717,14 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) arg.iov[0].iov_len = sizeof(rep.th); net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); -#ifdef CONFIG_TCP_MD5SIG +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) + /* Invalid TCP option size or twice included auth */ + if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, NULL)) + return; + rcu_read_lock(); - hash_location = tcp_parse_md5sig_option(th); +#endif +#ifdef CONFIG_TCP_MD5SIG if (sk && sk_fullsock(sk)) { const union tcp_md5_addr *addr; int l3index; @@ -728,7 +735,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) l3index = tcp_v4_sdif(skb) ? inet_iif(skb) : 0; addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; key = tcp_md5_do_lookup(sk, l3index, addr, AF_INET); - } else if (hash_location) { + } else if (md5_hash_location) { const union tcp_md5_addr *addr; int sdif = tcp_v4_sdif(skb); int dif = inet_iif(skb); @@ -760,7 +767,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb); - if (genhash || memcmp(hash_location, newhash, 16) != 0) + if (genhash || memcmp(md5_hash_location, newhash, 16) != 0) goto out; } @@ -835,7 +842,7 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) __TCP_INC_STATS(net, TCP_MIB_OUTRSTS); local_bh_enable(); -#ifdef CONFIG_TCP_MD5SIG +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) out: rcu_read_unlock(); #endif diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index b5fa5ae53a47..ba968e856ca9 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -982,7 +982,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) u32 seq = 0, ack_seq = 0; struct tcp_md5sig_key *key = NULL; #ifdef CONFIG_TCP_MD5SIG - const __u8 *hash_location = NULL; + const __u8 *md5_hash_location = NULL; unsigned char newhash[16]; int genhash; struct sock *sk1 = NULL; @@ -1002,9 +1002,14 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) return; net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); -#ifdef CONFIG_TCP_MD5SIG +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) + /* Invalid TCP option size or twice included auth */ + if (tcp_parse_auth_options(th, &md5_hash_location, NULL)) + return; + rcu_read_lock(); - hash_location = tcp_parse_md5sig_option(th); +#endif +#ifdef CONFIG_TCP_MD5SIG if (sk && sk_fullsock(sk)) { int l3index; @@ -1013,7 +1018,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) */ l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0; key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index); - } else if (hash_location) { + } else if (md5_hash_location) { int dif = tcp_v6_iif_l3_slave(skb); int sdif = tcp_v6_sdif(skb); int l3index; @@ -1043,7 +1048,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) goto out; genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb); - if (genhash || memcmp(hash_location, newhash, 16) != 0) + if (genhash || memcmp(md5_hash_location, newhash, 16) != 0) goto out; } #endif @@ -1076,7 +1081,7 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, ipv6_get_dsfield(ipv6h), label, priority); -#ifdef CONFIG_TCP_MD5SIG +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) out: rcu_read_unlock(); #endif -- 2.37.2