diff options
| author | Dmitry Safonov <dima@arista.com> | 2023-10-23 20:22:04 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-10-27 10:35:45 +0100 |
| commit | 0a3a809089eb1d4a0a2fd0c16b520d603988c859 (patch) | |
| tree | b584ef3c79e149b5f9986ed02258d29a48569df8 /net/ipv4/tcp.c | |
| parent | 9427c6aa3ec92f66b3d38f5d5f7af6b94b648a66 (diff) | |
net/tcp: Verify inbound TCP-AO signed segments
Now there is a common function to verify signature on TCP segments:
tcp_inbound_hash(). It has checks for all possible cross-interactions
with MD5 signs as well as with unsigned segments.
The rules from RFC5925 are:
(1) Any TCP segment can have at max only one signature.
(2) TCP connections can't switch between using TCP-MD5 and TCP-AO.
(3) TCP-AO connections can't stop using AO, as well as unsigned
connections can't suddenly start using AO.
Co-developed-by: Francesco Ruggeri <fruggeri@arista.com>
Signed-off-by: Francesco Ruggeri <fruggeri@arista.com>
Co-developed-by: Salam Noureddine <noureddine@arista.com>
Signed-off-by: Salam Noureddine <noureddine@arista.com>
Signed-off-by: Dmitry Safonov <dima@arista.com>
Acked-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp.c')
| -rw-r--r-- | net/ipv4/tcp.c | 39 |
1 files changed, 8 insertions, 31 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 369e2a41bc1b..eb71212a09d8 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4375,42 +4375,23 @@ EXPORT_SYMBOL(tcp_md5_hash_key); enum skb_drop_reason tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, const void *saddr, const void *daddr, - int family, int dif, int sdif) + int family, int l3index, const __u8 *hash_location) { - /* - * This gets called for each TCP segment that arrives - * so we want to be efficient. + /* This gets called for each TCP segment that has TCP-MD5 option. * We have 3 drop cases: * o No MD5 hash and one expected. * o MD5 hash and we're not expecting one. * o MD5 hash and its wrong. */ - const __u8 *hash_location = NULL; - struct tcp_md5sig_key *hash_expected; const struct tcphdr *th = tcp_hdr(skb); const struct tcp_sock *tp = tcp_sk(sk); - int genhash, l3index; + struct tcp_md5sig_key *key; u8 newhash[16]; + int genhash; - /* sdif set, means packet ingressed via a device - * in an L3 domain and dif is set to the l3mdev - */ - l3index = sdif ? dif : 0; - - hash_expected = tcp_md5_do_lookup(sk, l3index, saddr, family); - 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) - return SKB_NOT_DROPPED_YET; + key = tcp_md5_do_lookup(sk, l3index, saddr, family); - if (hash_expected && !hash_location) { - NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND); - return SKB_DROP_REASON_TCP_MD5NOTFOUND; - } - - if (!hash_expected && hash_location) { + if (!key && hash_location) { NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED); return SKB_DROP_REASON_TCP_MD5UNEXPECTED; } @@ -4420,14 +4401,10 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, * IPv4-mapped case. */ if (family == AF_INET) - genhash = tcp_v4_md5_hash_skb(newhash, - hash_expected, - NULL, skb); + genhash = tcp_v4_md5_hash_skb(newhash, key, NULL, skb); else - genhash = tp->af_specific->calc_md5_hash(newhash, - hash_expected, + genhash = tp->af_specific->calc_md5_hash(newhash, key, NULL, skb); - if (genhash || memcmp(hash_location, newhash, 16) != 0) { NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE); if (family == AF_INET) { |