Commit da7dfaa6 authored by Dmitry Safonov's avatar Dmitry Safonov Committed by Paolo Abeni
Browse files

net/tcp: Consistently align TCP-AO option in the header 



Currently functions that pre-calculate TCP header options length use
unaligned TCP-AO header + MAC-length for skb reservation.
And the functions that actually write TCP-AO options into skb do align
the header. Nothing good can come out of this for ((maclen % 4) != 0).

Provide tcp_ao_len_aligned() helper and use it everywhere for TCP
header options space calculations.

Fixes: 1e03d32b ("net/tcp: Add TCP-AO sign to outgoing packets")
Signed-off-by: default avatarDmitry Safonov <dima@arista.com>
Reviewed-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 714589c2

include/net/tcp_ao.h

+6 −0
Original line number Diff line number Diff line
@@ -62,11 +62,17 @@ static inline int tcp_ao_maclen(const struct tcp_ao_key *key) 
	return key->maclen;

}



/* Use tcp_ao_len_aligned() for TCP header calculations */

static inline int tcp_ao_len(const struct tcp_ao_key *key)

{

	return tcp_ao_maclen(key) + sizeof(struct tcp_ao_hdr);

}



static inline int tcp_ao_len_aligned(const struct tcp_ao_key *key)

{

	return round_up(tcp_ao_len(key), 4);

}



static inline unsigned int tcp_ao_digest_size(struct tcp_ao_key *key)

{

	return key->digest_size;

net/ipv4/tcp_ao.c

+2 −2
Original line number Diff line number Diff line
@@ -1100,7 +1100,7 @@ void tcp_ao_connect_init(struct sock *sk) 
			ao_info->current_key = key;

		if (!ao_info->rnext_key)

			ao_info->rnext_key = key;

		tp->tcp_header_len += tcp_ao_len(key);

		tp->tcp_header_len += tcp_ao_len_aligned(key);



		ao_info->lisn = htonl(tp->write_seq);

		ao_info->snd_sne = 0;
@@ -1346,7 +1346,7 @@ static int tcp_ao_parse_crypto(struct tcp_ao_add *cmd, struct tcp_ao_key *key) 
	syn_tcp_option_space -= TCPOLEN_MSS_ALIGNED;

	syn_tcp_option_space -= TCPOLEN_TSTAMP_ALIGNED;

	syn_tcp_option_space -= TCPOLEN_WSCALE_ALIGNED;

	if (tcp_ao_len(key) > syn_tcp_option_space) {

	if (tcp_ao_len_aligned(key) > syn_tcp_option_space) {

		err = -EMSGSIZE;

		goto err_kfree;

	}

net/ipv4/tcp_ipv4.c

+2 −2
Original line number Diff line number Diff line
@@ -690,7 +690,7 @@ static bool tcp_v4_ao_sign_reset(const struct sock *sk, struct sk_buff *skb, 


	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);

	arg->iov[0].iov_len += tcp_ao_len_aligned(key);

	reply->doff = arg->iov[0].iov_len / 4;



	if (tcp_ao_hash_hdr(AF_INET, (char *)&reply_options[1],
@@ -978,7 +978,7 @@ static void tcp_v4_send_ack(const struct sock *sk, 
					  (tcp_ao_len(key->ao_key) << 16) |

					  (key->ao_key->sndid << 8) |

					  key->rcv_next);

		arg.iov[0].iov_len += round_up(tcp_ao_len(key->ao_key), 4);

		arg.iov[0].iov_len += tcp_ao_len_aligned(key->ao_key);

		rep.th.doff = arg.iov[0].iov_len / 4;



		tcp_ao_hash_hdr(AF_INET, (char *)&rep.opt[offset],

net/ipv4/tcp_minisocks.c

+1 −1
Original line number Diff line number Diff line
@@ -615,7 +615,7 @@ struct sock *tcp_create_openreq_child(const struct sock *sk, 
	ao_key = treq->af_specific->ao_lookup(sk, req,

				tcp_rsk(req)->ao_keyid, -1);

	if (ao_key)

		newtp->tcp_header_len += tcp_ao_len(ao_key);

		newtp->tcp_header_len += tcp_ao_len_aligned(ao_key);

 #endif

	if (skb->len >= TCP_MSS_DEFAULT + newtp->tcp_header_len)

		newicsk->icsk_ack.last_seg_size = skb->len - newtp->tcp_header_len;

net/ipv4/tcp_output.c

+3 −3
Original line number Diff line number Diff line
@@ -825,7 +825,7 @@ static unsigned int tcp_syn_options(struct sock *sk, struct sk_buff *skb, 
		timestamps = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_timestamps);

		if (tcp_key_is_ao(key)) {

			opts->options |= OPTION_AO;

			remaining -= tcp_ao_len(key->ao_key);

			remaining -= tcp_ao_len_aligned(key->ao_key);

		}

	}
@@ -915,7 +915,7 @@ static unsigned int tcp_synack_options(const struct sock *sk, 
			ireq->tstamp_ok &= !ireq->sack_ok;

	} else if (tcp_key_is_ao(key)) {

		opts->options |= OPTION_AO;

		remaining -= tcp_ao_len(key->ao_key);

		remaining -= tcp_ao_len_aligned(key->ao_key);

		ireq->tstamp_ok &= !ireq->sack_ok;

	}
@@ -982,7 +982,7 @@ static unsigned int tcp_established_options(struct sock *sk, struct sk_buff *skb 
		size += TCPOLEN_MD5SIG_ALIGNED;

	} else if (tcp_key_is_ao(key)) {

		opts->options |= OPTION_AO;

		size += tcp_ao_len(key->ao_key);

		size += tcp_ao_len_aligned(key->ao_key);

	}



	if (likely(tp->rx_opt.tstamp_ok)) {