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Message-ID: <ZNy3+f6ZtDKfsQ5C@vergenet.net>
Date: Wed, 16 Aug 2023 13:50:17 +0200
From: Simon Horman <horms@...nel.org>
To: Dmitry Safonov <dima@...sta.com>
Cc: David Ahern <dsahern@...nel.org>, Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>, Jakub Kicinski <kuba@...nel.org>,
"David S. Miller" <davem@...emloft.net>,
linux-kernel@...r.kernel.org, Andy Lutomirski <luto@...capital.net>,
Ard Biesheuvel <ardb@...nel.org>,
Bob Gilligan <gilligan@...sta.com>,
Dan Carpenter <error27@...il.com>,
David Laight <David.Laight@...lab.com>,
Dmitry Safonov <0x7f454c46@...il.com>,
Donald Cassidy <dcassidy@...hat.com>,
Eric Biggers <ebiggers@...nel.org>,
"Eric W. Biederman" <ebiederm@...ssion.com>,
Francesco Ruggeri <fruggeri05@...il.com>,
"Gaillardetz, Dominik" <dgaillar@...na.com>,
Herbert Xu <herbert@...dor.apana.org.au>,
Hideaki YOSHIFUJI <yoshfuji@...ux-ipv6.org>,
Ivan Delalande <colona@...sta.com>,
Leonard Crestez <cdleonard@...il.com>,
"Nassiri, Mohammad" <mnassiri@...na.com>,
Salam Noureddine <noureddine@...sta.com>,
Simon Horman <simon.horman@...igine.com>,
"Tetreault, Francois" <ftetreau@...na.com>, netdev@...r.kernel.org
Subject: Re: [PATCH v10 net-next 08/23] net/tcp: Add AO sign to RST packets
On Tue, Aug 15, 2023 at 08:14:37PM +0100, Dmitry Safonov wrote:
> Wire up sending resets to TCP-AO hashing.
>
> Co-developed-by: Francesco Ruggeri <fruggeri@...sta.com>
> Signed-off-by: Francesco Ruggeri <fruggeri@...sta.com>
> Co-developed-by: Salam Noureddine <noureddine@...sta.com>
> Signed-off-by: Salam Noureddine <noureddine@...sta.com>
> Signed-off-by: Dmitry Safonov <dima@...sta.com>
> Acked-by: David Ahern <dsahern@...nel.org>
> ---
> include/net/tcp_ao.h | 12 +++++
> net/ipv4/tcp_ao.c | 104 ++++++++++++++++++++++++++++++++++++++++++-
> net/ipv4/tcp_ipv4.c | 69 ++++++++++++++++++++++------
> net/ipv6/tcp_ipv6.c | 70 ++++++++++++++++++++++-------
> 4 files changed, 225 insertions(+), 30 deletions(-)
>
> diff --git a/include/net/tcp_ao.h b/include/net/tcp_ao.h
> index e685ad9db949..67f997aabd9c 100644
> --- a/include/net/tcp_ao.h
> +++ b/include/net/tcp_ao.h
> @@ -117,12 +117,24 @@ int tcp_ao_hash_skb(unsigned short int family,
> const u8 *tkey, int hash_offset, u32 sne);
> int tcp_parse_ao(struct sock *sk, int cmd, unsigned short int family,
> sockptr_t optval, int optlen);
> +struct tcp_ao_key *tcp_ao_established_key(struct tcp_ao_info *ao,
> + int sndid, int rcvid);
> int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx,
> unsigned int len, struct tcp_sigpool *hp);
> void tcp_ao_destroy_sock(struct sock *sk);
> struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk,
> const union tcp_ao_addr *addr,
> int family, int sndid, int rcvid);
> +int tcp_ao_hash_hdr(unsigned short 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 tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb,
> + const struct tcp_ao_hdr *aoh, int l3index, u32 seq,
> + struct tcp_ao_key **key, char **traffic_key,
> + bool *allocated_traffic_key, u8 *keyid, u32 *sne);
> +
> /* ipv4 specific functions */
> int tcp_v4_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen);
> struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk,
> diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c
...
> @@ -435,6 +495,46 @@ 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, u32 seq,
> + struct tcp_ao_key **key, char **traffic_key,
> + bool *allocated_traffic_key, u8 *keyid, u32 *sne)
> +{
> + 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)) {
> + return -1;
> + } else {
> + struct tcp_ao_key *rnext_key;
> +
> + if (sk->sk_state == TCP_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;
> +}
> +
> static int tcp_ao_cache_traffic_keys(const struct sock *sk,
> struct tcp_ao_info *ao,
> struct tcp_ao_key *ao_key)
> diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
> index 31169971cc56..f07a12f478d4 100644
> --- a/net/ipv4/tcp_ipv4.c
> +++ b/net/ipv4/tcp_ipv4.c
> @@ -657,6 +657,52 @@ void tcp_v4_send_check(struct sock *sk, struct sk_buff *skb)
> }
> EXPORT_SYMBOL(tcp_v4_send_check);
>
> +#define REPLY_OPTIONS_LEN (MAX_TCP_OPTION_SPACE / sizeof(__be32))
> +
> +static bool tcp_v4_ao_sign_reset(const struct sock *sk, struct sk_buff *skb,
> + const struct tcp_ao_hdr *aoh,
> + struct ip_reply_arg *arg, struct tcphdr *reply,
> + __be32 reply_options[REPLY_OPTIONS_LEN])
> +{
> +#ifdef CONFIG_TCP_AO
> + int sdif = tcp_v4_sdif(skb);
> + int dif = inet_iif(skb);
> + int l3index = sdif ? dif : 0;
> + bool allocated_traffic_key;
> + struct tcp_ao_key *key;
> + char *traffic_key;
> + bool drop = true;
> + u32 ao_sne = 0;
> + u8 keyid;
> +
> + rcu_read_lock();
> + if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, reply->seq,
> + &key, &traffic_key, &allocated_traffic_key,
> + &keyid, &ao_sne))
Hi Dmitry,
The type of the 4th parameter of tcp_ao_prepare_reset() (seq) is u32,
but here a __be32 value is passed.
Also, it seems that parameter is unused by tcp_ao_prepare_reset().
> + goto out;
> +
> + 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);
> + reply->doff = arg->iov[0].iov_len / 4;
> +
> + if (tcp_ao_hash_hdr(AF_INET, (char *)&reply_options[1],
> + key, traffic_key,
> + (union tcp_ao_addr *)&ip_hdr(skb)->saddr,
> + (union tcp_ao_addr *)&ip_hdr(skb)->daddr,
> + reply, ao_sne))
> + goto out;
> + drop = false;
> +out:
> + rcu_read_unlock();
> + if (allocated_traffic_key)
> + kfree(traffic_key);
> + return drop;
> +#else
> + return true;
> +#endif
> +}
> +
> /*
> * This routine will send an RST to the other tcp.
> *
...
> diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
...
> @@ -1064,6 +1088,19 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
> ack_seq = ntohl(th->seq) + th->syn + th->fin + skb->len -
> (th->doff << 2);
>
> +#ifdef CONFIG_TCP_AO
> + if (aoh) {
> + int l3index;
> +
> + l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
> + if (tcp_ao_prepare_reset(sk, skb, aoh, l3index, htonl(seq),
Ditto.
> + &ao_key, &traffic_key,
> + &allocated_traffic_key,
> + &rcv_next, &ao_sne))
> + goto out;
> + }
> +#endif
> +
> if (sk) {
> oif = sk->sk_bound_dev_if;
> if (sk_fullsock(sk)) {
...
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