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Message-ID: <20231009230722.76268-9-dima@arista.com> Date: Tue, 10 Oct 2023 00:06:59 +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 v14 net-next 08/23] net/tcp: Add AO sign to RST packets Wire up sending resets to TCP-AO hashing. 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/tcp.h | 7 ++- include/net/tcp_ao.h | 12 +++++ net/ipv4/tcp_ao.c | 104 ++++++++++++++++++++++++++++++++++++++++++- net/ipv4/tcp_ipv4.c | 69 ++++++++++++++++++++++------ net/ipv6/tcp_ipv6.c | 96 ++++++++++++++++++++++++++++----------- 5 files changed, 245 insertions(+), 43 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index a619c429a8bd..dc74908ffa5a 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2220,7 +2220,12 @@ static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops, struct tcp_key { union { - struct tcp_ao_key *ao_key; + struct { + struct tcp_ao_key *ao_key; + u32 sne; + char *traffic_key; + u8 rcv_next; + }; struct tcp_md5sig_key *md5_key; }; enum { diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h index fdd2f5091b98..629ab0365b83 100644 --- a/include/net/tcp_ao.h +++ b/include/net/tcp_ao.h @@ -120,12 +120,24 @@ int tcp_ao_hash_skb(unsigned short int family, const u8 *tkey, int hash_offset, u32 sne); int tcp_parse_ao(struct sock *sk, int cmd, unsigned short int family, sockptr_t optval, int optlen); +struct tcp_ao_key *tcp_ao_established_key(struct tcp_ao_info *ao, + int sndid, int rcvid); int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx, unsigned int len, struct tcp_sigpool *hp); void tcp_ao_destroy_sock(struct sock *sk); struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, const union tcp_ao_addr *addr, int family, int sndid, int rcvid); +int tcp_ao_hash_hdr(unsigned short family, char *ao_hash, + struct tcp_ao_key *key, const u8 *tkey, + const union tcp_ao_addr *daddr, + const union tcp_ao_addr *saddr, + const struct tcphdr *th, u32 sne); +int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb, + const struct tcp_ao_hdr *aoh, int l3index, + struct tcp_ao_key **key, char **traffic_key, + bool *allocated_traffic_key, u8 *keyid, u32 *sne); + /* ipv4 specific functions */ int tcp_v4_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen); struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk, diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index 6eb9241d14a3..df59924c3828 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -48,8 +48,8 @@ int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx, * it's known that the keys in ao_info are matching peer's * family/address/VRF/etc. */ -static struct tcp_ao_key *tcp_ao_established_key(struct tcp_ao_info *ao, - int sndid, int rcvid) +struct tcp_ao_key *tcp_ao_established_key(struct tcp_ao_info *ao, + int sndid, int rcvid) { struct tcp_ao_key *key; @@ -369,6 +369,66 @@ static int tcp_ao_hash_header(struct tcp_sigpool *hp, return err; } +int tcp_ao_hash_hdr(unsigned short int family, char *ao_hash, + struct tcp_ao_key *key, const u8 *tkey, + const union tcp_ao_addr *daddr, + const union tcp_ao_addr *saddr, + const struct tcphdr *th, u32 sne) +{ + int tkey_len = tcp_ao_digest_size(key); + int hash_offset = ao_hash - (char *)th; + struct tcp_sigpool hp; + void *hash_buf = NULL; + + hash_buf = kmalloc(tkey_len, GFP_ATOMIC); + if (!hash_buf) + goto clear_hash_noput; + + if (tcp_sigpool_start(key->tcp_sigpool_id, &hp)) + goto clear_hash_noput; + + if (crypto_ahash_setkey(crypto_ahash_reqtfm(hp.req), tkey, tkey_len)) + goto clear_hash; + + if (crypto_ahash_init(hp.req)) + goto clear_hash; + + if (tcp_ao_hash_sne(&hp, sne)) + goto clear_hash; + if (family == AF_INET) { + if (tcp_v4_ao_hash_pseudoheader(&hp, daddr->a4.s_addr, + saddr->a4.s_addr, th->doff * 4)) + goto clear_hash; +#if IS_ENABLED(CONFIG_IPV6) + } else if (family == AF_INET6) { + if (tcp_v6_ao_hash_pseudoheader(&hp, &daddr->a6, + &saddr->a6, th->doff * 4)) + goto clear_hash; +#endif + } else { + WARN_ON_ONCE(1); + goto clear_hash; + } + if (tcp_ao_hash_header(&hp, th, false, + ao_hash, hash_offset, tcp_ao_maclen(key))) + goto clear_hash; + ahash_request_set_crypt(hp.req, NULL, hash_buf, 0); + if (crypto_ahash_final(hp.req)) + goto clear_hash; + + memcpy(ao_hash, hash_buf, tcp_ao_maclen(key)); + tcp_sigpool_end(&hp); + kfree(hash_buf); + return 0; + +clear_hash: + tcp_sigpool_end(&hp); +clear_hash_noput: + memset(ao_hash, 0, tcp_ao_maclen(key)); + kfree(hash_buf); + return 1; +} + int tcp_ao_hash_skb(unsigned short int family, char *ao_hash, struct tcp_ao_key *key, const struct sock *sk, const struct sk_buff *skb, @@ -435,6 +495,46 @@ struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk, return tcp_ao_do_lookup(sk, addr, AF_INET, sndid, rcvid); } +int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb, + const struct tcp_ao_hdr *aoh, int l3index, + struct tcp_ao_key **key, char **traffic_key, + bool *allocated_traffic_key, u8 *keyid, u32 *sne) +{ + struct tcp_ao_info *ao_info; + + *allocated_traffic_key = false; + /* If there's no socket - than initial sisn/disn are unknown. + * Drop the segment. RFC5925 (7.7) advises to require graceful + * restart [RFC4724]. Alternatively, the RFC5925 advises to + * save/restore traffic keys before/after reboot. + * Linux TCP-AO support provides TCP_AO_ADD_KEY and TCP_AO_REPAIR + * options to restore a socket post-reboot. + */ + if (!sk) + return -ENOTCONN; + + if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV)) { + return -1; + } else { + struct tcp_ao_key *rnext_key; + + if (sk->sk_state == TCP_TIME_WAIT) + return -1; + ao_info = rcu_dereference(tcp_sk(sk)->ao_info); + if (!ao_info) + return -ENOENT; + + *key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1); + if (!*key) + return -ENOENT; + *traffic_key = snd_other_key(*key); + rnext_key = READ_ONCE(ao_info->rnext_key); + *keyid = rnext_key->rcvid; + *sne = 0; + } + return 0; +} + int tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb, struct tcp_ao_key *key, struct tcphdr *th, __u8 *hash_location) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index e731f168b1ee..6a7a7736ba6f 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -656,6 +656,52 @@ void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb) } EXPORT_SYMBOL(tcp_v4_send_check); +#define REPLY_OPTIONS_LEN (MAX_TCP_OPTION_SPACE / sizeof(__be32)) + +static bool tcp_v4_ao_sign_reset(const struct sock *sk, struct sk_buff *skb, + const struct tcp_ao_hdr *aoh, + struct ip_reply_arg *arg, struct tcphdr *reply, + __be32 reply_options[REPLY_OPTIONS_LEN]) +{ +#ifdef CONFIG_TCP_AO + int sdif = tcp_v4_sdif(skb); + int dif = inet_iif(skb); + int l3index = sdif ? dif : 0; + bool allocated_traffic_key; + struct tcp_ao_key *key; + char *traffic_key; + bool drop = true; + u32 ao_sne = 0; + u8 keyid; + + rcu_read_lock(); + if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, + &key, &traffic_key, &allocated_traffic_key, + &keyid, &ao_sne)) + goto out; + + reply_options[0] = htonl((TCPOPT_AO << 24) | (tcp_ao_len(key) << 16) | + (aoh->rnext_keyid << 8) | keyid); + arg->iov[0].iov_len += round_up(tcp_ao_len(key), 4); + reply->doff = arg->iov[0].iov_len / 4; + + if (tcp_ao_hash_hdr(AF_INET, (char *)&reply_options[1], + key, traffic_key, + (union tcp_ao_addr *)&ip_hdr(skb)->saddr, + (union tcp_ao_addr *)&ip_hdr(skb)->daddr, + reply, ao_sne)) + goto out; + drop = false; +out: + rcu_read_unlock(); + if (allocated_traffic_key) + kfree(traffic_key); + return drop; +#else + return true; +#endif +} + /* * This routine will send an RST to the other tcp. * @@ -669,28 +715,21 @@ EXPORT_SYMBOL(tcp_v4_send_check); * Exception: precedence violation. We do not implement it in any case. */ -#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) -#endif - static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb) { const struct tcphdr *th = tcp_hdr(skb); struct { struct tcphdr th; - __be32 opt[OPTION_BYTES / sizeof(__be32)]; + __be32 opt[REPLY_OPTIONS_LEN]; } rep; + const __u8 *md5_hash_location = NULL; + const struct tcp_ao_hdr *aoh; struct ip_reply_arg arg; #ifdef CONFIG_TCP_MD5SIG - const __u8 *md5_hash_location = NULL; struct tcp_md5sig_key *key = NULL; unsigned char newhash[16]; - int genhash; struct sock *sk1 = NULL; + int genhash; #endif u64 transmit_time = 0; struct sock *ctl_sk; @@ -727,11 +766,15 @@ 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 + /* Invalid TCP option size or twice included auth */ - if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, NULL)) + if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh)) return; + if (aoh && tcp_v4_ao_sign_reset(sk, skb, aoh, &arg, &rep.th, rep.opt)) + return; + +#ifdef CONFIG_TCP_MD5SIG rcu_read_lock(); if (sk && sk_fullsock(sk)) { const union tcp_md5_addr *addr; diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 6ba1fccbfa2e..594eb074e5e5 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -853,8 +853,8 @@ const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = { static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 tsval, u32 tsecr, - int oif, struct tcp_md5sig_key *key, int rst, - u8 tclass, __be32 label, u32 priority, u32 txhash) + int oif, int rst, u8 tclass, __be32 label, + u32 priority, u32 txhash, struct tcp_key *key) { const struct tcphdr *th = tcp_hdr(skb); struct tcphdr *t1; @@ -869,13 +869,13 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 if (tsecr) tot_len += TCPOLEN_TSTAMP_ALIGNED; -#ifdef CONFIG_TCP_MD5SIG - if (key) + if (tcp_key_is_md5(key)) tot_len += TCPOLEN_MD5SIG_ALIGNED; -#endif + if (tcp_key_is_ao(key)) + tot_len += tcp_ao_len(key->ao_key); #ifdef CONFIG_MPTCP - if (rst && !key) { + if (rst && !tcp_key_is_md5(key)) { mrst = mptcp_reset_option(skb); if (mrst) @@ -916,14 +916,28 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 *topt++ = mrst; #ifdef CONFIG_TCP_MD5SIG - if (key) { + if (tcp_key_is_md5(key)) { *topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) | (TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG); - tcp_v6_md5_hash_hdr((__u8 *)topt, key, + tcp_v6_md5_hash_hdr((__u8 *)topt, key->md5_key, &ipv6_hdr(skb)->saddr, &ipv6_hdr(skb)->daddr, t1); } #endif +#ifdef CONFIG_TCP_AO + if (tcp_key_is_ao(key)) { + *topt++ = htonl((TCPOPT_AO << 24) | + (tcp_ao_len(key->ao_key) << 16) | + (key->ao_key->sndid << 8) | + (key->rcv_next)); + + tcp_ao_hash_hdr(AF_INET6, (char *)topt, key->ao_key, + key->traffic_key, + (union tcp_ao_addr *)&ipv6_hdr(skb)->saddr, + (union tcp_ao_addr *)&ipv6_hdr(skb)->daddr, + t1, key->sne); + } +#endif memset(&fl6, 0, sizeof(fl6)); fl6.daddr = ipv6_hdr(skb)->saddr; @@ -986,19 +1000,23 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) { const struct tcphdr *th = tcp_hdr(skb); struct ipv6hdr *ipv6h = ipv6_hdr(skb); - u32 seq = 0, ack_seq = 0; - struct tcp_md5sig_key *key = NULL; -#ifdef CONFIG_TCP_MD5SIG const __u8 *md5_hash_location = NULL; - unsigned char newhash[16]; - int genhash; - struct sock *sk1 = NULL; +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) + bool allocated_traffic_key = false; #endif + const struct tcp_ao_hdr *aoh; + struct tcp_key key = {}; + u32 seq = 0, ack_seq = 0; __be32 label = 0; u32 priority = 0; struct net *net; u32 txhash = 0; int oif = 0; +#ifdef CONFIG_TCP_MD5SIG + unsigned char newhash[16]; + int genhash; + struct sock *sk1 = NULL; +#endif if (th->rst) return; @@ -1010,12 +1028,11 @@ 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 /* Invalid TCP option size or twice included auth */ - if (tcp_parse_auth_options(th, &md5_hash_location, NULL)) + if (tcp_parse_auth_options(th, &md5_hash_location, &aoh)) return; - rcu_read_lock(); +#ifdef CONFIG_TCP_MD5SIG if (sk && sk_fullsock(sk)) { int l3index; @@ -1023,7 +1040,9 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) * in an L3 domain and inet_iif is set to it. */ l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0; - key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index); + key.md5_key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index); + if (key.md5_key) + key.type = TCP_KEY_MD5; } else if (md5_hash_location) { int dif = tcp_v6_iif_l3_slave(skb); int sdif = tcp_v6_sdif(skb); @@ -1048,11 +1067,12 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) */ l3index = tcp_v6_sdif(skb) ? dif : 0; - key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr, l3index); - if (!key) + key.md5_key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr, l3index); + if (!key.md5_key) goto out; + key.type = TCP_KEY_MD5; - genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb); + genhash = tcp_v6_md5_hash_skb(newhash, key.md5_key, NULL, skb); if (genhash || memcmp(md5_hash_location, newhash, 16) != 0) goto out; } @@ -1064,6 +1084,20 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len - (th->doff << 2); +#ifdef CONFIG_TCP_AO + if (aoh) { + int l3index; + + l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0; + if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, + &key.ao_key, &key.traffic_key, + &allocated_traffic_key, + &key.rcv_next, &key.sne)) + goto out; + key.type = TCP_KEY_AO; + } +#endif + if (sk) { oif = sk->sk_bound_dev_if; if (sk_fullsock(sk)) { @@ -1083,22 +1117,30 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb) label = ip6_flowlabel(ipv6h); } - tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1, - ipv6_get_dsfield(ipv6h), label, priority, txhash); + tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, 1, + ipv6_get_dsfield(ipv6h), label, priority, txhash, + &key); -#ifdef CONFIG_TCP_MD5SIG +#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO) out: + if (allocated_traffic_key) + kfree(key.traffic_key); rcu_read_unlock(); #endif } static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq, u32 ack, u32 win, u32 tsval, u32 tsecr, int oif, - struct tcp_md5sig_key *key, u8 tclass, + struct tcp_md5sig_key *md5_key, u8 tclass, __be32 label, u32 priority, u32 txhash) { - tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0, - tclass, label, priority, txhash); + struct tcp_key key = { + .md5_key = md5_key, + .type = md5_key ? TCP_KEY_MD5 : TCP_KEY_NONE, + }; + + tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, 0, + tclass, label, priority, txhash, &key); } static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb) -- 2.42.0
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