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Message-ID: <20231004223629.166300-8-dima@arista.com> Date: Wed, 4 Oct 2023 23:36:11 +0100 From: Dmitry Safonov <dima@...sta.com> To: David Ahern <dsahern@...nel.org>, Eric Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>, Jakub Kicinski <kuba@...nel.org>, "David S. Miller" <davem@...emloft.net> Cc: linux-kernel@...r.kernel.org, Dmitry Safonov <dima@...sta.com>, Andy Lutomirski <luto@...capital.net>, Ard Biesheuvel <ardb@...nel.org>, Bob Gilligan <gilligan@...sta.com>, Dan Carpenter <error27@...il.com>, David Laight <David.Laight@...lab.com>, Dmitry Safonov <0x7f454c46@...il.com>, Donald Cassidy <dcassidy@...hat.com>, Eric Biggers <ebiggers@...nel.org>, "Eric W. Biederman" <ebiederm@...ssion.com>, Francesco Ruggeri <fruggeri05@...il.com>, "Gaillardetz, Dominik" <dgaillar@...na.com>, Herbert Xu <herbert@...dor.apana.org.au>, Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>, Ivan Delalande <colona@...sta.com>, Leonard Crestez <cdleonard@...il.com>, "Nassiri, Mohammad" <mnassiri@...na.com>, Salam Noureddine <noureddine@...sta.com>, Simon Horman <simon.horman@...igine.com>, "Tetreault, Francois" <ftetreau@...na.com>, netdev@...r.kernel.org Subject: [PATCH v13 net-next 07/23] net/tcp: Add tcp_parse_auth_options() 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@...sta.com> Signed-off-by: Francesco Ruggeri <fruggeri@...sta.com> Co-developed-by: Salam Noureddine <noureddine@...sta.com> Signed-off-by: Salam Noureddine <noureddine@...sta.com> Signed-off-by: Dmitry Safonov <dima@...sta.com> Acked-by: David Ahern <dsahern@...nel.org> --- include/net/dropreason-core.h | 6 ++++++ include/net/tcp.h | 24 ++++++++++++++++++++- include/net/tcp_ao.h | 17 ++++++++++++++- net/ipv4/tcp.c | 3 ++- net/ipv4/tcp_input.c | 39 ++++++++++++++++++++++++++--------- net/ipv4/tcp_ipv4.c | 15 +++++++++----- net/ipv6/tcp_ipv6.c | 11 ++++++---- 7 files changed, 93 insertions(+), 22 deletions(-) diff --git a/include/net/dropreason-core.h b/include/net/dropreason-core.h index a587e83fc169..216cde184db1 100644 --- a/include/net/dropreason-core.h +++ b/include/net/dropreason-core.h @@ -20,6 +20,7 @@ FN(IP_NOPROTO) \ FN(SOCKET_RCVBUFF) \ FN(PROTO_MEM) \ + FN(TCP_AUTH_HDR) \ FN(TCP_MD5NOTFOUND) \ FN(TCP_MD5UNEXPECTED) \ FN(TCP_MD5FAILURE) \ @@ -141,6 +142,11 @@ enum skb_drop_reason { * drop out of udp_memory_allocated. */ SKB_DROP_REASON_PROTO_MEM, + /** + * @SKB_DROP_REASON_TCP_AUTH_HDR: TCP-MD5 or TCP-AO hashes are met + * twice or set incorrectly. + */ + SKB_DROP_REASON_TCP_AUTH_HDR, /** * @SKB_DROP_REASON_TCP_MD5NOTFOUND: no MD5 hash and one expected, * corresponding to LINUX_MIB_TCPMD5NOTFOUND diff --git a/include/net/tcp.h b/include/net/tcp.h index a18678ffcaa7..1c6942299765 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -426,7 +426,6 @@ 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 @@ -2635,6 +2634,29 @@ 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; +} + static inline bool tcp_ao_required(struct sock *sk, const void *saddr, int family) { diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h index 0b86bc05d8cf..fdd2f5091b98 100644 --- a/include/net/tcp_ao.h +++ b/include/net/tcp_ao.h @@ -152,7 +152,9 @@ int tcp_v6_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen); void tcp_ao_established(struct sock *sk); void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb); void tcp_ao_connect_init(struct sock *sk); - +void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb, + struct tcp_request_sock *treq, + unsigned short int family); #else /* CONFIG_TCP_AO */ static inline int tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb, @@ -185,4 +187,17 @@ static inline void tcp_ao_connect_init(struct sock *sk) } #endif +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) +int tcp_do_parse_auth_options(const struct tcphdr *th, + const u8 **md5_hash, const u8 **ao_hash); +#else +static inline int tcp_do_parse_auth_options(const struct tcphdr *th, + const u8 **md5_hash, const u8 **ao_hash) +{ + *md5_hash = NULL; + *ao_hash = NULL; + return 0; +} +#endif + #endif /* _TCP_AO_H */ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 898f9119ea37..9e38699d714a 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4392,7 +4392,8 @@ 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 SKB_DROP_REASON_TCP_AUTH_HDR; /* 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 d87ceb0cebed..281afbabd77f 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4225,39 +4225,58 @@ 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 f357538140f6..e731f168b1ee 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -669,7 +669,9 @@ 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 defined(CONFIG_TCP_MD5SIG) #define OPTION_BYTES TCPOLEN_MD5SIG_ALIGNED #else #define OPTION_BYTES sizeof(__be32) @@ -684,8 +686,8 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) } rep; struct ip_reply_arg arg; #ifdef CONFIG_TCP_MD5SIG + const __u8 *md5_hash_location = NULL; struct tcp_md5sig_key *key = NULL; - const __u8 *hash_location = NULL; unsigned char newhash[16]; int genhash; struct sock *sk1 = NULL; @@ -726,8 +728,11 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); #ifdef CONFIG_TCP_MD5SIG + /* 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); if (sk && sk_fullsock(sk)) { const union tcp_md5_addr *addr; int l3index; @@ -738,7 +743,7 @@ 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); @@ -770,7 +775,7 @@ 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; } diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 4c01d6863fe5..3009a62f034f 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -989,7 +989,7 @@ 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; @@ -1011,8 +1011,11 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev); #ifdef CONFIG_TCP_MD5SIG + /* 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); if (sk && sk_fullsock(sk)) { int l3index; @@ -1021,7 +1024,7 @@ 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; @@ -1050,7 +1053,7 @@ 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 -- 2.42.0
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