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Miller" Cc: Dmitry Safonov , Andy Lutomirski , Ard Biesheuvel , Bob Gilligan , Dan Carpenter , David Laight , Dmitry Safonov <0x7f454c46@gmail.com>, Eric Biggers , "Eric W. Biederman" , Francesco Ruggeri , Herbert Xu , Hideaki YOSHIFUJI , Ivan Delalande , Leonard Crestez , Salam Noureddine , netdev@vger.kernel.org, Francesco Ruggeri Subject: [PATCH v5 15/21] net/tcp: Add tcp_hash_fail() ratelimited logs Date: Mon, 3 Apr 2023 22:34:14 +0100 Message-Id: <20230403213420.1576559-16-dima@arista.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230403213420.1576559-1-dima@arista.com> References: <20230403213420.1576559-1-dima@arista.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org Add a helper for logging connection-detailed messages for failed TCP hash verification (both MD5 and AO). 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 --- include/net/tcp.h | 17 ++++++++++++++--- include/net/tcp_ao.h | 29 +++++++++++++++++++++++++++++ net/ipv4/tcp.c | 23 +++++++++++++---------- net/ipv4/tcp_ao.c | 7 +++++++ 4 files changed, 63 insertions(+), 13 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 45343a0a128c..7b5d4ee8f6b0 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -2604,12 +2604,19 @@ tcp_inbound_hash(struct sock *sk, const struct request_sock *req, int l3index; /* Invalid option or two times meet any of auth options */ - if (tcp_parse_auth_options(th, &md5_location, &aoh)) + if (tcp_parse_auth_options(th, &md5_location, &aoh)) { + tcp_hash_fail("TCP segment has incorrect auth options set", + family, skb, ""); return SKB_DROP_REASON_TCP_AUTH_HDR; + } if (req) { - if (tcp_rsk_used_ao(req) != !!aoh) + if (tcp_rsk_used_ao(req) != !!aoh) { + tcp_hash_fail("TCP connection can't start/end using TCP-AO", + family, skb, "%s", + !aoh ? "missing AO" : "AO signed"); return SKB_DROP_REASON_TCP_AOFAILURE; + } } /* sdif set, means packet ingressed via a device @@ -2624,10 +2631,14 @@ tcp_inbound_hash(struct sock *sk, const struct request_sock *req, * the last key is impossible to remove, so there's * always at least one current_key. */ - if (tcp_ao_required(sk, saddr, family, true)) + if (tcp_ao_required(sk, saddr, family, true)) { + tcp_hash_fail("AO hash is required, but not found", + family, skb, "L3 index %d", l3index); return SKB_DROP_REASON_TCP_AONOTFOUND; + } if (unlikely(tcp_md5_do_lookup(sk, l3index, saddr, family))) { NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5NOTFOUND); + tcp_hash_fail("MD5 Hash not found", family, skb, ""); return SKB_DROP_REASON_TCP_MD5NOTFOUND; } return SKB_NOT_DROPPED_YET; diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h index bd67e3680a2b..391b8260c325 100644 --- a/include/net/tcp_ao.h +++ b/include/net/tcp_ao.h @@ -105,6 +105,35 @@ struct tcp_ao_info { struct rcu_head rcu; }; +#define tcp_hash_fail(msg, family, skb, fmt, ...) \ +do { \ + const struct tcphdr *th = tcp_hdr(skb); \ + char hdr_flags[5] = {}; \ + char *f = hdr_flags; \ + \ + if (th->fin) \ + *f++ = 'F'; \ + if (th->syn) \ + *f++ = 'S'; \ + if (th->rst) \ + *f++ = 'R'; \ + if (th->ack) \ + *f++ = 'A'; \ + if (f != hdr_flags) \ + *f = ' '; \ + if (family == AF_INET) { \ + net_info_ratelimited("%s for (%pI4, %d)->(%pI4, %d) %s" fmt "\n", \ + msg, &ip_hdr(skb)->saddr, ntohs(th->source), \ + &ip_hdr(skb)->daddr, ntohs(th->dest), \ + hdr_flags, ##__VA_ARGS__); \ + } else { \ + net_info_ratelimited("%s for [%pI6c]:%u->[%pI6c]:%u %s" fmt "\n", \ + msg, &ipv6_hdr(skb)->saddr, ntohs(th->source), \ + &ipv6_hdr(skb)->daddr, ntohs(th->dest), \ + hdr_flags, ##__VA_ARGS__); \ + } \ +} while (0) + #ifdef CONFIG_TCP_AO /* TCP-AO structures and functions */ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 95d872ae8d82..6d892fd2abe3 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -4484,7 +4484,6 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, * o MD5 hash and we're not expecting one. * o MD5 hash and its wrong. */ - const struct tcphdr *th = tcp_hdr(skb); struct tcp_sock *tp = tcp_sk(sk); struct tcp_md5sig_key *key; int genhash; @@ -4494,6 +4493,7 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, if (!key && hash_location) { NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5UNEXPECTED); + tcp_hash_fail("Unexpected MD5 Hash found", family, skb, ""); return SKB_DROP_REASON_TCP_MD5UNEXPECTED; } @@ -4509,16 +4509,19 @@ tcp_inbound_md5_hash(const struct sock *sk, const struct sk_buff *skb, if (genhash || memcmp(hash_location, newhash, 16) != 0) { NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPMD5FAILURE); if (family == AF_INET) { - net_info_ratelimited("MD5 Hash failed for (%pI4, %d)->(%pI4, %d)%s L3 index %d\n", - saddr, ntohs(th->source), - daddr, ntohs(th->dest), - genhash ? " tcp_v4_calc_md5_hash failed" - : "", l3index); + tcp_hash_fail("MD5 Hash failed", AF_INET, skb, "%s L3 index %d", + genhash ? "tcp_v4_calc_md5_hash failed" + : "", l3index); } else { - net_info_ratelimited("MD5 Hash %s for [%pI6c]:%u->[%pI6c]:%u L3 index %d\n", - genhash ? "failed" : "mismatch", - saddr, ntohs(th->source), - daddr, ntohs(th->dest), l3index); + if (genhash) { + tcp_hash_fail("MD5 Hash failed", + AF_INET6, skb, "L3 index %d", + l3index); + } else { + tcp_hash_fail("MD5 Hash mismatch", + AF_INET6, skb, "L3 index %d", + l3index); + } } return SKB_DROP_REASON_TCP_MD5FAILURE; } diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c index 8fec1af5ebd7..8c74965b7575 100644 --- a/net/ipv4/tcp_ao.c +++ b/net/ipv4/tcp_ao.c @@ -671,6 +671,8 @@ tcp_ao_verify_hash(const struct sock *sk, const struct sk_buff *skb, NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOBAD); atomic64_inc(&info->counters.pkt_bad); atomic64_inc(&key->pkt_bad); + tcp_hash_fail("AO hash wrong length", family, skb, + "%u != %d", maclen, tcp_ao_maclen(key)); return SKB_DROP_REASON_TCP_AOFAILURE; } @@ -681,6 +683,7 @@ tcp_ao_verify_hash(const struct sock *sk, const struct sk_buff *skb, NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOBAD); atomic64_inc(&info->counters.pkt_bad); atomic64_inc(&key->pkt_bad); + tcp_hash_fail("AO hash mismatch", family, skb, ""); return SKB_DROP_REASON_TCP_AOFAILURE; } NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOGOOD); @@ -706,6 +709,8 @@ tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb, info = rcu_dereference(tcp_sk(sk)->ao_info); if (!info) { NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOKEYNOTFOUND); + tcp_hash_fail("AO key not found", family, skb, + "keyid: %u", aoh->keyid); return SKB_DROP_REASON_TCP_AOUNEXPECTED; } @@ -804,6 +809,8 @@ tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb, key_not_found: NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOKEYNOTFOUND); atomic64_inc(&info->counters.key_not_found); + tcp_hash_fail("Requested by the peer AO key id not found", + family, skb, ""); return SKB_DROP_REASON_TCP_AOKEYNOTFOUND; } EXPORT_SYMBOL_GPL(tcp_inbound_ao_hash);