From ba7783ad45c8f0fb7a70640f6b6fcdc54ed48412 Mon Sep 17 00:00:00 2001 From: Dmitry Safonov Date: Mon, 23 Oct 2023 20:22:00 +0100 Subject: net/tcp: Add AO sign to RST packets Wire up sending resets to TCP-AO hashing. Co-developed-by: Francesco Ruggeri Signed-off-by: Francesco Ruggeri Co-developed-by: Salam Noureddine Signed-off-by: Salam Noureddine Signed-off-by: Dmitry Safonov Acked-by: David Ahern Signed-off-by: David S. Miller --- net/ipv4/tcp_ao.c | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 100 insertions(+), 2 deletions(-) (limited to 'net/ipv4/tcp_ao.c') diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index 007f29a2531f..b8afe78ff057 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -48,8 +48,8 @@ clear_hash: * 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 +495,44 @@ 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_key *rnext_key; + 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 | TCPF_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) -- cgit v1.2.3