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net/tcp: Add tcp_hash_fail() ratelimited logs

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Add a helper for logging connection-detailed messages for failed TCP
hash verification (both MD5 and 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>
This commit is contained in:
Dmitry Safonov 2023-10-23 20:22:07 +01:00 committed by David S. Miller
parent 64382c71a5
commit 2717b5adea
4 changed files with 61 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
include/net/tcp.h
View File

@ -2748,12 +2748,18 @@ 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) {
NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOBAD);
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;
}
}
@ -2770,10 +2776,14 @@ 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;

29
include/net/tcp_ao.h
View File

@ -118,6 +118,35 @@ 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 */

23
net/ipv4/tcp.c
View File

@ -4383,7 +4383,6 @@ 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);
const struct tcp_sock *tp = tcp_sk(sk);
struct tcp_md5sig_key *key;
u8 newhash[16];
@ -4393,6 +4392,7 @@ 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;
}
@ -4408,16 +4408,19 @@ 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;
}

7
net/ipv4/tcp_ao.c
View File

@ -800,6 +800,8 @@ 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;
}
@ -814,6 +816,7 @@ 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, "");
kfree(hash_buf);
return SKB_DROP_REASON_TCP_AOFAILURE;
}
@ -841,6 +844,8 @@ 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;
}
@ -942,6 +947,8 @@ verify_hash:
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;
}