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net/tcp: Add AO sign to RST packets

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Wire up sending resets to TCP-AO hashing.

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 20:22:00 +01:00 committed by David S. Miller
parent f7dca36fc5
commit ba7783ad45
5 changed files with 245 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
include/net/tcp.h
View File

@ -2258,7 +2258,12 @@ static inline __u32 cookie_init_sequence(const struct tcp_request_sock_ops *ops,
struct tcp_key {
union {
struct tcp_ao_key *ao_key;
struct {
struct tcp_ao_key *ao_key;
char *traffic_key;
u32 sne;
u8 rcv_next;
};
struct tcp_md5sig_key *md5_key;
};
enum {

12
include/net/tcp_ao.h
View File

@ -120,12 +120,24 @@ 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,
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,

102
net/ipv4/tcp_ao.c
View File

@ -48,8 +48,8 @@ int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx,
* it's known that the keys in ao_info are matching peer's
* family/address/VRF/etc.
*/
static struct tcp_ao_key *tcp_ao_established_key(struct tcp_ao_info *ao,
int sndid, int rcvid)
struct tcp_ao_key *tcp_ao_established_key(struct tcp_ao_info *ao,
int sndid, int rcvid)
{
struct tcp_ao_key *key;
@ -369,6 +369,66 @@ static int tcp_ao_hash_header(struct tcp_sigpool *hp,
return err;
}
int tcp_ao_hash_hdr(unsigned short int 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 tkey_len = tcp_ao_digest_size(key);
int hash_offset = ao_hash - (char *)th;
struct tcp_sigpool hp;
void *hash_buf = NULL;
hash_buf = kmalloc(tkey_len, GFP_ATOMIC);
if (!hash_buf)
goto clear_hash_noput;
if (tcp_sigpool_start(key->tcp_sigpool_id, &hp))
goto clear_hash_noput;
if (crypto_ahash_setkey(crypto_ahash_reqtfm(hp.req), tkey, tkey_len))
goto clear_hash;
if (crypto_ahash_init(hp.req))
goto clear_hash;
if (tcp_ao_hash_sne(&hp, sne))
goto clear_hash;
if (family == AF_INET) {
if (tcp_v4_ao_hash_pseudoheader(&hp, daddr->a4.s_addr,
saddr->a4.s_addr, th->doff * 4))
goto clear_hash;
#if IS_ENABLED(CONFIG_IPV6)
} else if (family == AF_INET6) {
if (tcp_v6_ao_hash_pseudoheader(&hp, &daddr->a6,
&saddr->a6, th->doff * 4))
goto clear_hash;
#endif
} else {
WARN_ON_ONCE(1);
goto clear_hash;
}
if (tcp_ao_hash_header(&hp, th, false,
ao_hash, hash_offset, tcp_ao_maclen(key)))
goto clear_hash;
ahash_request_set_crypt(hp.req, NULL, hash_buf, 0);
if (crypto_ahash_final(hp.req))
goto clear_hash;
memcpy(ao_hash, hash_buf, tcp_ao_maclen(key));
tcp_sigpool_end(&hp);
kfree(hash_buf);
return 0;
clear_hash:
tcp_sigpool_end(&hp);
clear_hash_noput:
memset(ao_hash, 0, tcp_ao_maclen(key));
kfree(hash_buf);
return 1;
}
int tcp_ao_hash_skb(unsigned short int family,
char *ao_hash, struct tcp_ao_key *key,
const struct sock *sk, const struct sk_buff *skb,
@ -435,6 +495,44 @@ 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,
struct tcp_ao_key **key, char **traffic_key,
bool *allocated_traffic_key, u8 *keyid, u32 *sne)
{
struct tcp_ao_key *rnext_key;
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 | TCPF_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;
}
int tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb,
struct tcp_ao_key *key, struct tcphdr *th,
__u8 *hash_location)

69
net/ipv4/tcp_ipv4.c
View File

@ -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,
&key, &traffic_key, &allocated_traffic_key,
&keyid, &ao_sne))
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.
*
@ -670,28 +716,21 @@ EXPORT_SYMBOL(tcp_v4_send_check);
* Exception: precedence violation. We do not implement it in any case.
*/
#ifdef CONFIG_TCP_AO
#define OPTION_BYTES MAX_TCP_OPTION_SPACE
#elif defined(CONFIG_TCP_MD5SIG)
#define OPTION_BYTES TCPOLEN_MD5SIG_ALIGNED
#else
#define OPTION_BYTES sizeof(__be32)
#endif
static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
{
const struct tcphdr *th = tcp_hdr(skb);
struct {
struct tcphdr th;
__be32 opt[OPTION_BYTES / sizeof(__be32)];
__be32 opt[REPLY_OPTIONS_LEN];
} rep;
const __u8 *md5_hash_location = NULL;
const struct tcp_ao_hdr *aoh;
struct ip_reply_arg arg;
#ifdef CONFIG_TCP_MD5SIG
const __u8 *md5_hash_location = NULL;
struct tcp_md5sig_key *key = NULL;
unsigned char newhash[16];
int genhash;
struct sock *sk1 = NULL;
int genhash;
#endif
u64 transmit_time = 0;
struct sock *ctl_sk;
@ -728,11 +767,15 @@ static void tcp_v4_send_reset(const struct sock *sk, struct sk_buff *skb)
arg.iov[0].iov_len = sizeof(rep.th);
net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
#ifdef CONFIG_TCP_MD5SIG
/* Invalid TCP option size or twice included auth */
if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, NULL))
if (tcp_parse_auth_options(tcp_hdr(skb), &md5_hash_location, &aoh))
return;
if (aoh && tcp_v4_ao_sign_reset(sk, skb, aoh, &arg, &rep.th, rep.opt))
return;
#ifdef CONFIG_TCP_MD5SIG
rcu_read_lock();
if (sk && sk_fullsock(sk)) {
const union tcp_md5_addr *addr;

98
net/ipv6/tcp_ipv6.c
View File

@ -854,8 +854,8 @@ const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32 seq,
u32 ack, u32 win, u32 tsval, u32 tsecr,
int oif, struct tcp_md5sig_key *key, int rst,
u8 tclass, __be32 label, u32 priority, u32 txhash)
int oif, int rst, u8 tclass, __be32 label,
u32 priority, u32 txhash, struct tcp_key *key)
{
const struct tcphdr *th = tcp_hdr(skb);
struct tcphdr *t1;
@ -870,13 +870,13 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32
if (tsecr)
tot_len += TCPOLEN_TSTAMP_ALIGNED;
#ifdef CONFIG_TCP_MD5SIG
if (key)
if (tcp_key_is_md5(key))
tot_len += TCPOLEN_MD5SIG_ALIGNED;
#endif
if (tcp_key_is_ao(key))
tot_len += tcp_ao_len(key->ao_key);
#ifdef CONFIG_MPTCP
if (rst && !key) {
if (rst && !tcp_key_is_md5(key)) {
mrst = mptcp_reset_option(skb);
if (mrst)
@ -917,14 +917,28 @@ static void tcp_v6_send_response(const struct sock *sk, struct sk_buff *skb, u32
*topt++ = mrst;
#ifdef CONFIG_TCP_MD5SIG
if (key) {
if (tcp_key_is_md5(key)) {
*topt++ = htonl((TCPOPT_NOP << 24) | (TCPOPT_NOP << 16) |
(TCPOPT_MD5SIG << 8) | TCPOLEN_MD5SIG);
tcp_v6_md5_hash_hdr((__u8 *)topt, key,
tcp_v6_md5_hash_hdr((__u8 *)topt, key->md5_key,
&ipv6_hdr(skb)->saddr,
&ipv6_hdr(skb)->daddr, t1);
}
#endif
#ifdef CONFIG_TCP_AO
if (tcp_key_is_ao(key)) {
*topt++ = htonl((TCPOPT_AO << 24) |
(tcp_ao_len(key->ao_key) << 16) |
(key->ao_key->sndid << 8) |
(key->rcv_next));
tcp_ao_hash_hdr(AF_INET6, (char *)topt, key->ao_key,
key->traffic_key,
(union tcp_ao_addr *)&ipv6_hdr(skb)->saddr,
(union tcp_ao_addr *)&ipv6_hdr(skb)->daddr,
t1, key->sne);
}
#endif
memset(&fl6, 0, sizeof(fl6));
fl6.daddr = ipv6_hdr(skb)->saddr;
@ -987,19 +1001,23 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
{
const struct tcphdr *th = tcp_hdr(skb);
struct ipv6hdr *ipv6h = ipv6_hdr(skb);
u32 seq = 0, ack_seq = 0;
struct tcp_md5sig_key *key = NULL;
#ifdef CONFIG_TCP_MD5SIG
const __u8 *md5_hash_location = NULL;
unsigned char newhash[16];
int genhash;
struct sock *sk1 = NULL;
#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
bool allocated_traffic_key = false;
#endif
const struct tcp_ao_hdr *aoh;
struct tcp_key key = {};
u32 seq = 0, ack_seq = 0;
__be32 label = 0;
u32 priority = 0;
struct net *net;
u32 txhash = 0;
int oif = 0;
#ifdef CONFIG_TCP_MD5SIG
unsigned char newhash[16];
int genhash;
struct sock *sk1 = NULL;
#endif
if (th->rst)
return;
@ -1011,12 +1029,13 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
return;
net = sk ? sock_net(sk) : dev_net(skb_dst(skb)->dev);
#ifdef CONFIG_TCP_MD5SIG
/* Invalid TCP option size or twice included auth */
if (tcp_parse_auth_options(th, &md5_hash_location, NULL))
if (tcp_parse_auth_options(th, &md5_hash_location, &aoh))
return;
#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
rcu_read_lock();
#endif
#ifdef CONFIG_TCP_MD5SIG
if (sk && sk_fullsock(sk)) {
int l3index;
@ -1024,7 +1043,9 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
* in an L3 domain and inet_iif is set to it.
*/
l3index = tcp_v6_sdif(skb) ? tcp_v6_iif_l3_slave(skb) : 0;
key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index);
key.md5_key = tcp_v6_md5_do_lookup(sk, &ipv6h->saddr, l3index);
if (key.md5_key)
key.type = TCP_KEY_MD5;
} else if (md5_hash_location) {
int dif = tcp_v6_iif_l3_slave(skb);
int sdif = tcp_v6_sdif(skb);
@ -1049,11 +1070,12 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
*/
l3index = tcp_v6_sdif(skb) ? dif : 0;
key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr, l3index);
if (!key)
key.md5_key = tcp_v6_md5_do_lookup(sk1, &ipv6h->saddr, l3index);
if (!key.md5_key)
goto out;
key.type = TCP_KEY_MD5;
genhash = tcp_v6_md5_hash_skb(newhash, key, NULL, skb);
genhash = tcp_v6_md5_hash_skb(newhash, key.md5_key, NULL, skb);
if (genhash || memcmp(md5_hash_location, newhash, 16) != 0)
goto out;
}
@ -1065,6 +1087,20 @@ 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,
&key.ao_key, &key.traffic_key,
&allocated_traffic_key,
&key.rcv_next, &key.sne))
goto out;
key.type = TCP_KEY_AO;
}
#endif
if (sk) {
oif = sk->sk_bound_dev_if;
if (sk_fullsock(sk)) {
@ -1084,22 +1120,30 @@ static void tcp_v6_send_reset(const struct sock *sk, struct sk_buff *skb)
label = ip6_flowlabel(ipv6h);
}
tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, key, 1,
ipv6_get_dsfield(ipv6h), label, priority, txhash);
tcp_v6_send_response(sk, skb, seq, ack_seq, 0, 0, 0, oif, 1,
ipv6_get_dsfield(ipv6h), label, priority, txhash,
&key);
#ifdef CONFIG_TCP_MD5SIG
#if defined(CONFIG_TCP_MD5SIG) || defined(CONFIG_TCP_AO)
out:
if (allocated_traffic_key)
kfree(key.traffic_key);
rcu_read_unlock();
#endif
}
static void tcp_v6_send_ack(const struct sock *sk, struct sk_buff *skb, u32 seq,
u32 ack, u32 win, u32 tsval, u32 tsecr, int oif,
struct tcp_md5sig_key *key, u8 tclass,
struct tcp_md5sig_key *md5_key, u8 tclass,
__be32 label, u32 priority, u32 txhash)
{
tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, key, 0,
tclass, label, priority, txhash);
struct tcp_key key = {
.md5_key = md5_key,
.type = md5_key ? TCP_KEY_MD5 : TCP_KEY_NONE,
};
tcp_v6_send_response(sk, skb, seq, ack, win, tsval, tsecr, oif, 0,
tclass, label, priority, txhash, &key);
}
static void tcp_v6_timewait_ack(struct sock *sk, struct sk_buff *skb)