1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * INET An implementation of the TCP Authentication Option (TCP-AO). 4 * See RFC5925. 5 * 6 * Authors: Dmitry Safonov <dima@arista.com> 7 * Francesco Ruggeri <fruggeri@arista.com> 8 * Salam Noureddine <noureddine@arista.com> 9 */ 10 #define pr_fmt(fmt) "TCP: " fmt 11 12 #include <crypto/hash.h> 13 #include <linux/inetdevice.h> 14 #include <linux/tcp.h> 15 16 #include <net/tcp.h> 17 #include <net/ipv6.h> 18 #include <net/icmp.h> 19 20 DEFINE_STATIC_KEY_DEFERRED_FALSE(tcp_ao_needed, HZ); 21 22 int tcp_ao_calc_traffic_key(struct tcp_ao_key *mkt, u8 *key, void *ctx, 23 unsigned int len, struct tcp_sigpool *hp) 24 { 25 struct scatterlist sg; 26 int ret; 27 28 if (crypto_ahash_setkey(crypto_ahash_reqtfm(hp->req), 29 mkt->key, mkt->keylen)) 30 goto clear_hash; 31 32 ret = crypto_ahash_init(hp->req); 33 if (ret) 34 goto clear_hash; 35 36 sg_init_one(&sg, ctx, len); 37 ahash_request_set_crypt(hp->req, &sg, key, len); 38 crypto_ahash_update(hp->req); 39 40 ret = crypto_ahash_final(hp->req); 41 if (ret) 42 goto clear_hash; 43 44 return 0; 45 clear_hash: 46 memset(key, 0, tcp_ao_digest_size(mkt)); 47 return 1; 48 } 49 50 bool tcp_ao_ignore_icmp(const struct sock *sk, int family, int type, int code) 51 { 52 bool ignore_icmp = false; 53 struct tcp_ao_info *ao; 54 55 if (!static_branch_unlikely(&tcp_ao_needed.key)) 56 return false; 57 58 /* RFC5925, 7.8: 59 * >> A TCP-AO implementation MUST default to ignore incoming ICMPv4 60 * messages of Type 3 (destination unreachable), Codes 2-4 (protocol 61 * unreachable, port unreachable, and fragmentation needed -- ’hard 62 * errors’), and ICMPv6 Type 1 (destination unreachable), Code 1 63 * (administratively prohibited) and Code 4 (port unreachable) intended 64 * for connections in synchronized states (ESTABLISHED, FIN-WAIT-1, FIN- 65 * WAIT-2, CLOSE-WAIT, CLOSING, LAST-ACK, TIME-WAIT) that match MKTs. 66 */ 67 if (family == AF_INET) { 68 if (type != ICMP_DEST_UNREACH) 69 return false; 70 if (code < ICMP_PROT_UNREACH || code > ICMP_FRAG_NEEDED) 71 return false; 72 } else { 73 if (type != ICMPV6_DEST_UNREACH) 74 return false; 75 if (code != ICMPV6_ADM_PROHIBITED && code != ICMPV6_PORT_UNREACH) 76 return false; 77 } 78 79 rcu_read_lock(); 80 switch (sk->sk_state) { 81 case TCP_TIME_WAIT: 82 ao = rcu_dereference(tcp_twsk(sk)->ao_info); 83 break; 84 case TCP_SYN_SENT: 85 case TCP_SYN_RECV: 86 case TCP_LISTEN: 87 case TCP_NEW_SYN_RECV: 88 /* RFC5925 specifies to ignore ICMPs *only* on connections 89 * in synchronized states. 90 */ 91 rcu_read_unlock(); 92 return false; 93 default: 94 ao = rcu_dereference(tcp_sk(sk)->ao_info); 95 } 96 97 if (ao && !ao->accept_icmps) { 98 ignore_icmp = true; 99 __NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAODROPPEDICMPS); 100 atomic64_inc(&ao->counters.dropped_icmp); 101 } 102 rcu_read_unlock(); 103 104 return ignore_icmp; 105 } 106 107 /* Optimized version of tcp_ao_do_lookup(): only for sockets for which 108 * it's known that the keys in ao_info are matching peer's 109 * family/address/VRF/etc. 110 */ 111 struct tcp_ao_key *tcp_ao_established_key(struct tcp_ao_info *ao, 112 int sndid, int rcvid) 113 { 114 struct tcp_ao_key *key; 115 116 hlist_for_each_entry_rcu(key, &ao->head, node) { 117 if ((sndid >= 0 && key->sndid != sndid) || 118 (rcvid >= 0 && key->rcvid != rcvid)) 119 continue; 120 return key; 121 } 122 123 return NULL; 124 } 125 126 static int ipv4_prefix_cmp(const struct in_addr *addr1, 127 const struct in_addr *addr2, 128 unsigned int prefixlen) 129 { 130 __be32 mask = inet_make_mask(prefixlen); 131 __be32 a1 = addr1->s_addr & mask; 132 __be32 a2 = addr2->s_addr & mask; 133 134 if (a1 == a2) 135 return 0; 136 return memcmp(&a1, &a2, sizeof(a1)); 137 } 138 139 static int __tcp_ao_key_cmp(const struct tcp_ao_key *key, int l3index, 140 const union tcp_ao_addr *addr, u8 prefixlen, 141 int family, int sndid, int rcvid) 142 { 143 if (sndid >= 0 && key->sndid != sndid) 144 return (key->sndid > sndid) ? 1 : -1; 145 if (rcvid >= 0 && key->rcvid != rcvid) 146 return (key->rcvid > rcvid) ? 1 : -1; 147 if (l3index >= 0 && (key->keyflags & TCP_AO_KEYF_IFINDEX)) { 148 if (key->l3index != l3index) 149 return (key->l3index > l3index) ? 1 : -1; 150 } 151 152 if (family == AF_UNSPEC) 153 return 0; 154 if (key->family != family) 155 return (key->family > family) ? 1 : -1; 156 157 if (family == AF_INET) { 158 if (ntohl(key->addr.a4.s_addr) == INADDR_ANY) 159 return 0; 160 if (ntohl(addr->a4.s_addr) == INADDR_ANY) 161 return 0; 162 return ipv4_prefix_cmp(&key->addr.a4, &addr->a4, prefixlen); 163 #if IS_ENABLED(CONFIG_IPV6) 164 } else { 165 if (ipv6_addr_any(&key->addr.a6) || ipv6_addr_any(&addr->a6)) 166 return 0; 167 if (ipv6_prefix_equal(&key->addr.a6, &addr->a6, prefixlen)) 168 return 0; 169 return memcmp(&key->addr.a6, &addr->a6, sizeof(addr->a6)); 170 #endif 171 } 172 return -1; 173 } 174 175 static int tcp_ao_key_cmp(const struct tcp_ao_key *key, int l3index, 176 const union tcp_ao_addr *addr, u8 prefixlen, 177 int family, int sndid, int rcvid) 178 { 179 #if IS_ENABLED(CONFIG_IPV6) 180 if (family == AF_INET6 && ipv6_addr_v4mapped(&addr->a6)) { 181 __be32 addr4 = addr->a6.s6_addr32[3]; 182 183 return __tcp_ao_key_cmp(key, l3index, 184 (union tcp_ao_addr *)&addr4, 185 prefixlen, AF_INET, sndid, rcvid); 186 } 187 #endif 188 return __tcp_ao_key_cmp(key, l3index, addr, 189 prefixlen, family, sndid, rcvid); 190 } 191 192 static struct tcp_ao_key *__tcp_ao_do_lookup(const struct sock *sk, int l3index, 193 const union tcp_ao_addr *addr, int family, u8 prefix, 194 int sndid, int rcvid) 195 { 196 struct tcp_ao_key *key; 197 struct tcp_ao_info *ao; 198 199 if (!static_branch_unlikely(&tcp_ao_needed.key)) 200 return NULL; 201 202 ao = rcu_dereference_check(tcp_sk(sk)->ao_info, 203 lockdep_sock_is_held(sk)); 204 if (!ao) 205 return NULL; 206 207 hlist_for_each_entry_rcu(key, &ao->head, node) { 208 u8 prefixlen = min(prefix, key->prefixlen); 209 210 if (!tcp_ao_key_cmp(key, l3index, addr, prefixlen, 211 family, sndid, rcvid)) 212 return key; 213 } 214 return NULL; 215 } 216 217 struct tcp_ao_key *tcp_ao_do_lookup(const struct sock *sk, int l3index, 218 const union tcp_ao_addr *addr, 219 int family, int sndid, int rcvid) 220 { 221 return __tcp_ao_do_lookup(sk, l3index, addr, family, U8_MAX, sndid, rcvid); 222 } 223 224 static struct tcp_ao_info *tcp_ao_alloc_info(gfp_t flags) 225 { 226 struct tcp_ao_info *ao; 227 228 ao = kzalloc(sizeof(*ao), flags); 229 if (!ao) 230 return NULL; 231 INIT_HLIST_HEAD(&ao->head); 232 refcount_set(&ao->refcnt, 1); 233 234 return ao; 235 } 236 237 static void tcp_ao_link_mkt(struct tcp_ao_info *ao, struct tcp_ao_key *mkt) 238 { 239 hlist_add_head_rcu(&mkt->node, &ao->head); 240 } 241 242 static struct tcp_ao_key *tcp_ao_copy_key(struct sock *sk, 243 struct tcp_ao_key *key) 244 { 245 struct tcp_ao_key *new_key; 246 247 new_key = sock_kmalloc(sk, tcp_ao_sizeof_key(key), 248 GFP_ATOMIC); 249 if (!new_key) 250 return NULL; 251 252 *new_key = *key; 253 INIT_HLIST_NODE(&new_key->node); 254 tcp_sigpool_get(new_key->tcp_sigpool_id); 255 atomic64_set(&new_key->pkt_good, 0); 256 atomic64_set(&new_key->pkt_bad, 0); 257 258 return new_key; 259 } 260 261 static void tcp_ao_key_free_rcu(struct rcu_head *head) 262 { 263 struct tcp_ao_key *key = container_of(head, struct tcp_ao_key, rcu); 264 265 tcp_sigpool_release(key->tcp_sigpool_id); 266 kfree_sensitive(key); 267 } 268 269 void tcp_ao_destroy_sock(struct sock *sk, bool twsk) 270 { 271 struct tcp_ao_info *ao; 272 struct tcp_ao_key *key; 273 struct hlist_node *n; 274 275 if (twsk) { 276 ao = rcu_dereference_protected(tcp_twsk(sk)->ao_info, 1); 277 tcp_twsk(sk)->ao_info = NULL; 278 } else { 279 ao = rcu_dereference_protected(tcp_sk(sk)->ao_info, 1); 280 tcp_sk(sk)->ao_info = NULL; 281 } 282 283 if (!ao || !refcount_dec_and_test(&ao->refcnt)) 284 return; 285 286 hlist_for_each_entry_safe(key, n, &ao->head, node) { 287 hlist_del_rcu(&key->node); 288 if (!twsk) 289 atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc); 290 call_rcu(&key->rcu, tcp_ao_key_free_rcu); 291 } 292 293 kfree_rcu(ao, rcu); 294 static_branch_slow_dec_deferred(&tcp_ao_needed); 295 } 296 297 void tcp_ao_time_wait(struct tcp_timewait_sock *tcptw, struct tcp_sock *tp) 298 { 299 struct tcp_ao_info *ao_info = rcu_dereference_protected(tp->ao_info, 1); 300 301 if (ao_info) { 302 struct tcp_ao_key *key; 303 struct hlist_node *n; 304 int omem = 0; 305 306 hlist_for_each_entry_safe(key, n, &ao_info->head, node) { 307 omem += tcp_ao_sizeof_key(key); 308 } 309 310 refcount_inc(&ao_info->refcnt); 311 atomic_sub(omem, &(((struct sock *)tp)->sk_omem_alloc)); 312 rcu_assign_pointer(tcptw->ao_info, ao_info); 313 } else { 314 tcptw->ao_info = NULL; 315 } 316 } 317 318 /* 4 tuple and ISNs are expected in NBO */ 319 static int tcp_v4_ao_calc_key(struct tcp_ao_key *mkt, u8 *key, 320 __be32 saddr, __be32 daddr, 321 __be16 sport, __be16 dport, 322 __be32 sisn, __be32 disn) 323 { 324 /* See RFC5926 3.1.1 */ 325 struct kdf_input_block { 326 u8 counter; 327 u8 label[6]; 328 struct tcp4_ao_context ctx; 329 __be16 outlen; 330 } __packed * tmp; 331 struct tcp_sigpool hp; 332 int err; 333 334 err = tcp_sigpool_start(mkt->tcp_sigpool_id, &hp); 335 if (err) 336 return err; 337 338 tmp = hp.scratch; 339 tmp->counter = 1; 340 memcpy(tmp->label, "TCP-AO", 6); 341 tmp->ctx.saddr = saddr; 342 tmp->ctx.daddr = daddr; 343 tmp->ctx.sport = sport; 344 tmp->ctx.dport = dport; 345 tmp->ctx.sisn = sisn; 346 tmp->ctx.disn = disn; 347 tmp->outlen = htons(tcp_ao_digest_size(mkt) * 8); /* in bits */ 348 349 err = tcp_ao_calc_traffic_key(mkt, key, tmp, sizeof(*tmp), &hp); 350 tcp_sigpool_end(&hp); 351 352 return err; 353 } 354 355 int tcp_v4_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key, 356 const struct sock *sk, 357 __be32 sisn, __be32 disn, bool send) 358 { 359 if (send) 360 return tcp_v4_ao_calc_key(mkt, key, sk->sk_rcv_saddr, 361 sk->sk_daddr, htons(sk->sk_num), 362 sk->sk_dport, sisn, disn); 363 else 364 return tcp_v4_ao_calc_key(mkt, key, sk->sk_daddr, 365 sk->sk_rcv_saddr, sk->sk_dport, 366 htons(sk->sk_num), disn, sisn); 367 } 368 369 static int tcp_ao_calc_key_sk(struct tcp_ao_key *mkt, u8 *key, 370 const struct sock *sk, 371 __be32 sisn, __be32 disn, bool send) 372 { 373 if (mkt->family == AF_INET) 374 return tcp_v4_ao_calc_key_sk(mkt, key, sk, sisn, disn, send); 375 #if IS_ENABLED(CONFIG_IPV6) 376 else if (mkt->family == AF_INET6) 377 return tcp_v6_ao_calc_key_sk(mkt, key, sk, sisn, disn, send); 378 #endif 379 else 380 return -EOPNOTSUPP; 381 } 382 383 int tcp_v4_ao_calc_key_rsk(struct tcp_ao_key *mkt, u8 *key, 384 struct request_sock *req) 385 { 386 struct inet_request_sock *ireq = inet_rsk(req); 387 388 return tcp_v4_ao_calc_key(mkt, key, 389 ireq->ir_loc_addr, ireq->ir_rmt_addr, 390 htons(ireq->ir_num), ireq->ir_rmt_port, 391 htonl(tcp_rsk(req)->snt_isn), 392 htonl(tcp_rsk(req)->rcv_isn)); 393 } 394 395 static int tcp_v4_ao_calc_key_skb(struct tcp_ao_key *mkt, u8 *key, 396 const struct sk_buff *skb, 397 __be32 sisn, __be32 disn) 398 { 399 const struct iphdr *iph = ip_hdr(skb); 400 const struct tcphdr *th = tcp_hdr(skb); 401 402 return tcp_v4_ao_calc_key(mkt, key, iph->saddr, iph->daddr, 403 th->source, th->dest, sisn, disn); 404 } 405 406 static int tcp_ao_calc_key_skb(struct tcp_ao_key *mkt, u8 *key, 407 const struct sk_buff *skb, 408 __be32 sisn, __be32 disn, int family) 409 { 410 if (family == AF_INET) 411 return tcp_v4_ao_calc_key_skb(mkt, key, skb, sisn, disn); 412 #if IS_ENABLED(CONFIG_IPV6) 413 else if (family == AF_INET6) 414 return tcp_v6_ao_calc_key_skb(mkt, key, skb, sisn, disn); 415 #endif 416 return -EAFNOSUPPORT; 417 } 418 419 static int tcp_v4_ao_hash_pseudoheader(struct tcp_sigpool *hp, 420 __be32 daddr, __be32 saddr, 421 int nbytes) 422 { 423 struct tcp4_pseudohdr *bp; 424 struct scatterlist sg; 425 426 bp = hp->scratch; 427 bp->saddr = saddr; 428 bp->daddr = daddr; 429 bp->pad = 0; 430 bp->protocol = IPPROTO_TCP; 431 bp->len = cpu_to_be16(nbytes); 432 433 sg_init_one(&sg, bp, sizeof(*bp)); 434 ahash_request_set_crypt(hp->req, &sg, NULL, sizeof(*bp)); 435 return crypto_ahash_update(hp->req); 436 } 437 438 static int tcp_ao_hash_pseudoheader(unsigned short int family, 439 const struct sock *sk, 440 const struct sk_buff *skb, 441 struct tcp_sigpool *hp, int nbytes) 442 { 443 const struct tcphdr *th = tcp_hdr(skb); 444 445 /* TODO: Can we rely on checksum being zero to mean outbound pkt? */ 446 if (!th->check) { 447 if (family == AF_INET) 448 return tcp_v4_ao_hash_pseudoheader(hp, sk->sk_daddr, 449 sk->sk_rcv_saddr, skb->len); 450 #if IS_ENABLED(CONFIG_IPV6) 451 else if (family == AF_INET6) 452 return tcp_v6_ao_hash_pseudoheader(hp, &sk->sk_v6_daddr, 453 &sk->sk_v6_rcv_saddr, skb->len); 454 #endif 455 else 456 return -EAFNOSUPPORT; 457 } 458 459 if (family == AF_INET) { 460 const struct iphdr *iph = ip_hdr(skb); 461 462 return tcp_v4_ao_hash_pseudoheader(hp, iph->daddr, 463 iph->saddr, skb->len); 464 #if IS_ENABLED(CONFIG_IPV6) 465 } else if (family == AF_INET6) { 466 const struct ipv6hdr *iph = ipv6_hdr(skb); 467 468 return tcp_v6_ao_hash_pseudoheader(hp, &iph->daddr, 469 &iph->saddr, skb->len); 470 #endif 471 } 472 return -EAFNOSUPPORT; 473 } 474 475 u32 tcp_ao_compute_sne(u32 next_sne, u32 next_seq, u32 seq) 476 { 477 u32 sne = next_sne; 478 479 if (before(seq, next_seq)) { 480 if (seq > next_seq) 481 sne--; 482 } else { 483 if (seq < next_seq) 484 sne++; 485 } 486 487 return sne; 488 } 489 490 /* tcp_ao_hash_sne(struct tcp_sigpool *hp) 491 * @hp - used for hashing 492 * @sne - sne value 493 */ 494 static int tcp_ao_hash_sne(struct tcp_sigpool *hp, u32 sne) 495 { 496 struct scatterlist sg; 497 __be32 *bp; 498 499 bp = (__be32 *)hp->scratch; 500 *bp = htonl(sne); 501 502 sg_init_one(&sg, bp, sizeof(*bp)); 503 ahash_request_set_crypt(hp->req, &sg, NULL, sizeof(*bp)); 504 return crypto_ahash_update(hp->req); 505 } 506 507 static int tcp_ao_hash_header(struct tcp_sigpool *hp, 508 const struct tcphdr *th, 509 bool exclude_options, u8 *hash, 510 int hash_offset, int hash_len) 511 { 512 int err, len = th->doff << 2; 513 struct scatterlist sg; 514 u8 *hdr = hp->scratch; 515 516 /* We are not allowed to change tcphdr, make a local copy */ 517 if (exclude_options) { 518 len = sizeof(*th) + sizeof(struct tcp_ao_hdr) + hash_len; 519 memcpy(hdr, th, sizeof(*th)); 520 memcpy(hdr + sizeof(*th), 521 (u8 *)th + hash_offset - sizeof(struct tcp_ao_hdr), 522 sizeof(struct tcp_ao_hdr)); 523 memset(hdr + sizeof(*th) + sizeof(struct tcp_ao_hdr), 524 0, hash_len); 525 ((struct tcphdr *)hdr)->check = 0; 526 } else { 527 len = th->doff << 2; 528 memcpy(hdr, th, len); 529 /* zero out tcp-ao hash */ 530 ((struct tcphdr *)hdr)->check = 0; 531 memset(hdr + hash_offset, 0, hash_len); 532 } 533 534 sg_init_one(&sg, hdr, len); 535 ahash_request_set_crypt(hp->req, &sg, NULL, len); 536 err = crypto_ahash_update(hp->req); 537 WARN_ON_ONCE(err != 0); 538 return err; 539 } 540 541 int tcp_ao_hash_hdr(unsigned short int family, char *ao_hash, 542 struct tcp_ao_key *key, const u8 *tkey, 543 const union tcp_ao_addr *daddr, 544 const union tcp_ao_addr *saddr, 545 const struct tcphdr *th, u32 sne) 546 { 547 int tkey_len = tcp_ao_digest_size(key); 548 int hash_offset = ao_hash - (char *)th; 549 struct tcp_sigpool hp; 550 void *hash_buf = NULL; 551 552 hash_buf = kmalloc(tkey_len, GFP_ATOMIC); 553 if (!hash_buf) 554 goto clear_hash_noput; 555 556 if (tcp_sigpool_start(key->tcp_sigpool_id, &hp)) 557 goto clear_hash_noput; 558 559 if (crypto_ahash_setkey(crypto_ahash_reqtfm(hp.req), tkey, tkey_len)) 560 goto clear_hash; 561 562 if (crypto_ahash_init(hp.req)) 563 goto clear_hash; 564 565 if (tcp_ao_hash_sne(&hp, sne)) 566 goto clear_hash; 567 if (family == AF_INET) { 568 if (tcp_v4_ao_hash_pseudoheader(&hp, daddr->a4.s_addr, 569 saddr->a4.s_addr, th->doff * 4)) 570 goto clear_hash; 571 #if IS_ENABLED(CONFIG_IPV6) 572 } else if (family == AF_INET6) { 573 if (tcp_v6_ao_hash_pseudoheader(&hp, &daddr->a6, 574 &saddr->a6, th->doff * 4)) 575 goto clear_hash; 576 #endif 577 } else { 578 WARN_ON_ONCE(1); 579 goto clear_hash; 580 } 581 if (tcp_ao_hash_header(&hp, th, 582 !!(key->keyflags & TCP_AO_KEYF_EXCLUDE_OPT), 583 ao_hash, hash_offset, tcp_ao_maclen(key))) 584 goto clear_hash; 585 ahash_request_set_crypt(hp.req, NULL, hash_buf, 0); 586 if (crypto_ahash_final(hp.req)) 587 goto clear_hash; 588 589 memcpy(ao_hash, hash_buf, tcp_ao_maclen(key)); 590 tcp_sigpool_end(&hp); 591 kfree(hash_buf); 592 return 0; 593 594 clear_hash: 595 tcp_sigpool_end(&hp); 596 clear_hash_noput: 597 memset(ao_hash, 0, tcp_ao_maclen(key)); 598 kfree(hash_buf); 599 return 1; 600 } 601 602 int tcp_ao_hash_skb(unsigned short int family, 603 char *ao_hash, struct tcp_ao_key *key, 604 const struct sock *sk, const struct sk_buff *skb, 605 const u8 *tkey, int hash_offset, u32 sne) 606 { 607 const struct tcphdr *th = tcp_hdr(skb); 608 int tkey_len = tcp_ao_digest_size(key); 609 struct tcp_sigpool hp; 610 void *hash_buf = NULL; 611 612 hash_buf = kmalloc(tkey_len, GFP_ATOMIC); 613 if (!hash_buf) 614 goto clear_hash_noput; 615 616 if (tcp_sigpool_start(key->tcp_sigpool_id, &hp)) 617 goto clear_hash_noput; 618 619 if (crypto_ahash_setkey(crypto_ahash_reqtfm(hp.req), tkey, tkey_len)) 620 goto clear_hash; 621 622 /* For now use sha1 by default. Depends on alg in tcp_ao_key */ 623 if (crypto_ahash_init(hp.req)) 624 goto clear_hash; 625 626 if (tcp_ao_hash_sne(&hp, sne)) 627 goto clear_hash; 628 if (tcp_ao_hash_pseudoheader(family, sk, skb, &hp, skb->len)) 629 goto clear_hash; 630 if (tcp_ao_hash_header(&hp, th, 631 !!(key->keyflags & TCP_AO_KEYF_EXCLUDE_OPT), 632 ao_hash, hash_offset, tcp_ao_maclen(key))) 633 goto clear_hash; 634 if (tcp_sigpool_hash_skb_data(&hp, skb, th->doff << 2)) 635 goto clear_hash; 636 ahash_request_set_crypt(hp.req, NULL, hash_buf, 0); 637 if (crypto_ahash_final(hp.req)) 638 goto clear_hash; 639 640 memcpy(ao_hash, hash_buf, tcp_ao_maclen(key)); 641 tcp_sigpool_end(&hp); 642 kfree(hash_buf); 643 return 0; 644 645 clear_hash: 646 tcp_sigpool_end(&hp); 647 clear_hash_noput: 648 memset(ao_hash, 0, tcp_ao_maclen(key)); 649 kfree(hash_buf); 650 return 1; 651 } 652 653 int tcp_v4_ao_hash_skb(char *ao_hash, struct tcp_ao_key *key, 654 const struct sock *sk, const struct sk_buff *skb, 655 const u8 *tkey, int hash_offset, u32 sne) 656 { 657 return tcp_ao_hash_skb(AF_INET, ao_hash, key, sk, skb, 658 tkey, hash_offset, sne); 659 } 660 661 int tcp_v4_ao_synack_hash(char *ao_hash, struct tcp_ao_key *ao_key, 662 struct request_sock *req, const struct sk_buff *skb, 663 int hash_offset, u32 sne) 664 { 665 void *hash_buf = NULL; 666 int err; 667 668 hash_buf = kmalloc(tcp_ao_digest_size(ao_key), GFP_ATOMIC); 669 if (!hash_buf) 670 return -ENOMEM; 671 672 err = tcp_v4_ao_calc_key_rsk(ao_key, hash_buf, req); 673 if (err) 674 goto out; 675 676 err = tcp_ao_hash_skb(AF_INET, ao_hash, ao_key, req_to_sk(req), skb, 677 hash_buf, hash_offset, sne); 678 out: 679 kfree(hash_buf); 680 return err; 681 } 682 683 struct tcp_ao_key *tcp_v4_ao_lookup_rsk(const struct sock *sk, 684 struct request_sock *req, 685 int sndid, int rcvid) 686 { 687 struct inet_request_sock *ireq = inet_rsk(req); 688 union tcp_ao_addr *addr = (union tcp_ao_addr *)&ireq->ir_rmt_addr; 689 int l3index; 690 691 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), ireq->ir_iif); 692 return tcp_ao_do_lookup(sk, l3index, addr, AF_INET, sndid, rcvid); 693 } 694 695 struct tcp_ao_key *tcp_v4_ao_lookup(const struct sock *sk, struct sock *addr_sk, 696 int sndid, int rcvid) 697 { 698 int l3index = l3mdev_master_ifindex_by_index(sock_net(sk), 699 addr_sk->sk_bound_dev_if); 700 union tcp_ao_addr *addr = (union tcp_ao_addr *)&addr_sk->sk_daddr; 701 702 return tcp_ao_do_lookup(sk, l3index, addr, AF_INET, sndid, rcvid); 703 } 704 705 int tcp_ao_prepare_reset(const struct sock *sk, struct sk_buff *skb, 706 const struct tcp_ao_hdr *aoh, int l3index, u32 seq, 707 struct tcp_ao_key **key, char **traffic_key, 708 bool *allocated_traffic_key, u8 *keyid, u32 *sne) 709 { 710 const struct tcphdr *th = tcp_hdr(skb); 711 struct tcp_ao_info *ao_info; 712 713 *allocated_traffic_key = false; 714 /* If there's no socket - than initial sisn/disn are unknown. 715 * Drop the segment. RFC5925 (7.7) advises to require graceful 716 * restart [RFC4724]. Alternatively, the RFC5925 advises to 717 * save/restore traffic keys before/after reboot. 718 * Linux TCP-AO support provides TCP_AO_ADD_KEY and TCP_AO_REPAIR 719 * options to restore a socket post-reboot. 720 */ 721 if (!sk) 722 return -ENOTCONN; 723 724 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV)) { 725 unsigned int family = READ_ONCE(sk->sk_family); 726 union tcp_ao_addr *addr; 727 __be32 disn, sisn; 728 729 if (sk->sk_state == TCP_NEW_SYN_RECV) { 730 struct request_sock *req = inet_reqsk(sk); 731 732 sisn = htonl(tcp_rsk(req)->rcv_isn); 733 disn = htonl(tcp_rsk(req)->snt_isn); 734 *sne = tcp_ao_compute_sne(0, tcp_rsk(req)->snt_isn, seq); 735 } else { 736 sisn = th->seq; 737 disn = 0; 738 } 739 if (IS_ENABLED(CONFIG_IPV6) && family == AF_INET6) 740 addr = (union tcp_md5_addr *)&ipv6_hdr(skb)->saddr; 741 else 742 addr = (union tcp_md5_addr *)&ip_hdr(skb)->saddr; 743 #if IS_ENABLED(CONFIG_IPV6) 744 if (family == AF_INET6 && ipv6_addr_v4mapped(&sk->sk_v6_daddr)) 745 family = AF_INET; 746 #endif 747 748 sk = sk_const_to_full_sk(sk); 749 ao_info = rcu_dereference(tcp_sk(sk)->ao_info); 750 if (!ao_info) 751 return -ENOENT; 752 *key = tcp_ao_do_lookup(sk, l3index, addr, family, 753 -1, aoh->rnext_keyid); 754 if (!*key) 755 return -ENOENT; 756 *traffic_key = kmalloc(tcp_ao_digest_size(*key), GFP_ATOMIC); 757 if (!*traffic_key) 758 return -ENOMEM; 759 *allocated_traffic_key = true; 760 if (tcp_ao_calc_key_skb(*key, *traffic_key, skb, 761 sisn, disn, family)) 762 return -1; 763 *keyid = (*key)->rcvid; 764 } else { 765 struct tcp_ao_key *rnext_key; 766 u32 snd_basis; 767 768 if (sk->sk_state == TCP_TIME_WAIT) { 769 ao_info = rcu_dereference(tcp_twsk(sk)->ao_info); 770 snd_basis = tcp_twsk(sk)->tw_snd_nxt; 771 } else { 772 ao_info = rcu_dereference(tcp_sk(sk)->ao_info); 773 snd_basis = tcp_sk(sk)->snd_una; 774 } 775 if (!ao_info) 776 return -ENOENT; 777 778 *key = tcp_ao_established_key(ao_info, aoh->rnext_keyid, -1); 779 if (!*key) 780 return -ENOENT; 781 *traffic_key = snd_other_key(*key); 782 rnext_key = READ_ONCE(ao_info->rnext_key); 783 *keyid = rnext_key->rcvid; 784 *sne = tcp_ao_compute_sne(READ_ONCE(ao_info->snd_sne), 785 snd_basis, seq); 786 } 787 return 0; 788 } 789 790 int tcp_ao_transmit_skb(struct sock *sk, struct sk_buff *skb, 791 struct tcp_ao_key *key, struct tcphdr *th, 792 __u8 *hash_location) 793 { 794 struct tcp_skb_cb *tcb = TCP_SKB_CB(skb); 795 struct tcp_sock *tp = tcp_sk(sk); 796 struct tcp_ao_info *ao; 797 void *tkey_buf = NULL; 798 u8 *traffic_key; 799 u32 sne; 800 801 ao = rcu_dereference_protected(tcp_sk(sk)->ao_info, 802 lockdep_sock_is_held(sk)); 803 traffic_key = snd_other_key(key); 804 if (unlikely(tcb->tcp_flags & TCPHDR_SYN)) { 805 __be32 disn; 806 807 if (!(tcb->tcp_flags & TCPHDR_ACK)) { 808 disn = 0; 809 tkey_buf = kmalloc(tcp_ao_digest_size(key), GFP_ATOMIC); 810 if (!tkey_buf) 811 return -ENOMEM; 812 traffic_key = tkey_buf; 813 } else { 814 disn = ao->risn; 815 } 816 tp->af_specific->ao_calc_key_sk(key, traffic_key, 817 sk, ao->lisn, disn, true); 818 } 819 sne = tcp_ao_compute_sne(READ_ONCE(ao->snd_sne), READ_ONCE(tp->snd_una), 820 ntohl(th->seq)); 821 tp->af_specific->calc_ao_hash(hash_location, key, sk, skb, traffic_key, 822 hash_location - (u8 *)th, sne); 823 kfree(tkey_buf); 824 return 0; 825 } 826 827 static struct tcp_ao_key *tcp_ao_inbound_lookup(unsigned short int family, 828 const struct sock *sk, const struct sk_buff *skb, 829 int sndid, int rcvid, int l3index) 830 { 831 if (family == AF_INET) { 832 const struct iphdr *iph = ip_hdr(skb); 833 834 return tcp_ao_do_lookup(sk, l3index, 835 (union tcp_ao_addr *)&iph->saddr, 836 AF_INET, sndid, rcvid); 837 } else { 838 const struct ipv6hdr *iph = ipv6_hdr(skb); 839 840 return tcp_ao_do_lookup(sk, l3index, 841 (union tcp_ao_addr *)&iph->saddr, 842 AF_INET6, sndid, rcvid); 843 } 844 } 845 846 void tcp_ao_syncookie(struct sock *sk, const struct sk_buff *skb, 847 struct tcp_request_sock *treq, 848 unsigned short int family, int l3index) 849 { 850 const struct tcphdr *th = tcp_hdr(skb); 851 const struct tcp_ao_hdr *aoh; 852 struct tcp_ao_key *key; 853 854 treq->maclen = 0; 855 856 if (tcp_parse_auth_options(th, NULL, &aoh) || !aoh) 857 return; 858 859 key = tcp_ao_inbound_lookup(family, sk, skb, -1, aoh->keyid, l3index); 860 if (!key) 861 /* Key not found, continue without TCP-AO */ 862 return; 863 864 treq->ao_rcv_next = aoh->keyid; 865 treq->ao_keyid = aoh->rnext_keyid; 866 treq->maclen = tcp_ao_maclen(key); 867 } 868 869 static enum skb_drop_reason 870 tcp_ao_verify_hash(const struct sock *sk, const struct sk_buff *skb, 871 unsigned short int family, struct tcp_ao_info *info, 872 const struct tcp_ao_hdr *aoh, struct tcp_ao_key *key, 873 u8 *traffic_key, u8 *phash, u32 sne, int l3index) 874 { 875 u8 maclen = aoh->length - sizeof(struct tcp_ao_hdr); 876 const struct tcphdr *th = tcp_hdr(skb); 877 void *hash_buf = NULL; 878 879 if (maclen != tcp_ao_maclen(key)) { 880 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOBAD); 881 atomic64_inc(&info->counters.pkt_bad); 882 atomic64_inc(&key->pkt_bad); 883 tcp_hash_fail("AO hash wrong length", family, skb, 884 "%u != %d L3index: %d", maclen, 885 tcp_ao_maclen(key), l3index); 886 return SKB_DROP_REASON_TCP_AOFAILURE; 887 } 888 889 hash_buf = kmalloc(tcp_ao_digest_size(key), GFP_ATOMIC); 890 if (!hash_buf) 891 return SKB_DROP_REASON_NOT_SPECIFIED; 892 893 /* XXX: make it per-AF callback? */ 894 tcp_ao_hash_skb(family, hash_buf, key, sk, skb, traffic_key, 895 (phash - (u8 *)th), sne); 896 if (memcmp(phash, hash_buf, maclen)) { 897 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOBAD); 898 atomic64_inc(&info->counters.pkt_bad); 899 atomic64_inc(&key->pkt_bad); 900 tcp_hash_fail("AO hash mismatch", family, skb, 901 "L3index: %d", l3index); 902 kfree(hash_buf); 903 return SKB_DROP_REASON_TCP_AOFAILURE; 904 } 905 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOGOOD); 906 atomic64_inc(&info->counters.pkt_good); 907 atomic64_inc(&key->pkt_good); 908 kfree(hash_buf); 909 return SKB_NOT_DROPPED_YET; 910 } 911 912 enum skb_drop_reason 913 tcp_inbound_ao_hash(struct sock *sk, const struct sk_buff *skb, 914 unsigned short int family, const struct request_sock *req, 915 int l3index, const struct tcp_ao_hdr *aoh) 916 { 917 const struct tcphdr *th = tcp_hdr(skb); 918 u8 *phash = (u8 *)(aoh + 1); /* hash goes just after the header */ 919 struct tcp_ao_info *info; 920 enum skb_drop_reason ret; 921 struct tcp_ao_key *key; 922 __be32 sisn, disn; 923 u8 *traffic_key; 924 u32 sne = 0; 925 926 info = rcu_dereference(tcp_sk(sk)->ao_info); 927 if (!info) { 928 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOKEYNOTFOUND); 929 tcp_hash_fail("AO key not found", family, skb, 930 "keyid: %u L3index: %d", aoh->keyid, l3index); 931 return SKB_DROP_REASON_TCP_AOUNEXPECTED; 932 } 933 934 if (unlikely(th->syn)) { 935 sisn = th->seq; 936 disn = 0; 937 } 938 939 /* Fast-path */ 940 if (likely((1 << sk->sk_state) & TCP_AO_ESTABLISHED)) { 941 enum skb_drop_reason err; 942 struct tcp_ao_key *current_key; 943 944 /* Check if this socket's rnext_key matches the keyid in the 945 * packet. If not we lookup the key based on the keyid 946 * matching the rcvid in the mkt. 947 */ 948 key = READ_ONCE(info->rnext_key); 949 if (key->rcvid != aoh->keyid) { 950 key = tcp_ao_established_key(info, -1, aoh->keyid); 951 if (!key) 952 goto key_not_found; 953 } 954 955 /* Delayed retransmitted SYN */ 956 if (unlikely(th->syn && !th->ack)) 957 goto verify_hash; 958 959 sne = tcp_ao_compute_sne(info->rcv_sne, tcp_sk(sk)->rcv_nxt, 960 ntohl(th->seq)); 961 /* Established socket, traffic key are cached */ 962 traffic_key = rcv_other_key(key); 963 err = tcp_ao_verify_hash(sk, skb, family, info, aoh, key, 964 traffic_key, phash, sne, l3index); 965 if (err) 966 return err; 967 current_key = READ_ONCE(info->current_key); 968 /* Key rotation: the peer asks us to use new key (RNext) */ 969 if (unlikely(aoh->rnext_keyid != current_key->sndid)) { 970 /* If the key is not found we do nothing. */ 971 key = tcp_ao_established_key(info, aoh->rnext_keyid, -1); 972 if (key) 973 /* pairs with tcp_ao_del_cmd */ 974 WRITE_ONCE(info->current_key, key); 975 } 976 return SKB_NOT_DROPPED_YET; 977 } 978 979 /* Lookup key based on peer address and keyid. 980 * current_key and rnext_key must not be used on tcp listen 981 * sockets as otherwise: 982 * - request sockets would race on those key pointers 983 * - tcp_ao_del_cmd() allows async key removal 984 */ 985 key = tcp_ao_inbound_lookup(family, sk, skb, -1, aoh->keyid, l3index); 986 if (!key) 987 goto key_not_found; 988 989 if (th->syn && !th->ack) 990 goto verify_hash; 991 992 if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_NEW_SYN_RECV)) { 993 /* Make the initial syn the likely case here */ 994 if (unlikely(req)) { 995 sne = tcp_ao_compute_sne(0, tcp_rsk(req)->rcv_isn, 996 ntohl(th->seq)); 997 sisn = htonl(tcp_rsk(req)->rcv_isn); 998 disn = htonl(tcp_rsk(req)->snt_isn); 999 } else if (unlikely(th->ack && !th->syn)) { 1000 /* Possible syncookie packet */ 1001 sisn = htonl(ntohl(th->seq) - 1); 1002 disn = htonl(ntohl(th->ack_seq) - 1); 1003 sne = tcp_ao_compute_sne(0, ntohl(sisn), 1004 ntohl(th->seq)); 1005 } else if (unlikely(!th->syn)) { 1006 /* no way to figure out initial sisn/disn - drop */ 1007 return SKB_DROP_REASON_TCP_FLAGS; 1008 } 1009 } else if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { 1010 disn = info->lisn; 1011 if (th->syn || th->rst) 1012 sisn = th->seq; 1013 else 1014 sisn = info->risn; 1015 } else { 1016 WARN_ONCE(1, "TCP-AO: Unexpected sk_state %d", sk->sk_state); 1017 return SKB_DROP_REASON_TCP_AOFAILURE; 1018 } 1019 verify_hash: 1020 traffic_key = kmalloc(tcp_ao_digest_size(key), GFP_ATOMIC); 1021 if (!traffic_key) 1022 return SKB_DROP_REASON_NOT_SPECIFIED; 1023 tcp_ao_calc_key_skb(key, traffic_key, skb, sisn, disn, family); 1024 ret = tcp_ao_verify_hash(sk, skb, family, info, aoh, key, 1025 traffic_key, phash, sne, l3index); 1026 kfree(traffic_key); 1027 return ret; 1028 1029 key_not_found: 1030 NET_INC_STATS(sock_net(sk), LINUX_MIB_TCPAOKEYNOTFOUND); 1031 atomic64_inc(&info->counters.key_not_found); 1032 tcp_hash_fail("Requested by the peer AO key id not found", 1033 family, skb, "L3index: %d", l3index); 1034 return SKB_DROP_REASON_TCP_AOKEYNOTFOUND; 1035 } 1036 1037 static int tcp_ao_cache_traffic_keys(const struct sock *sk, 1038 struct tcp_ao_info *ao, 1039 struct tcp_ao_key *ao_key) 1040 { 1041 u8 *traffic_key = snd_other_key(ao_key); 1042 int ret; 1043 1044 ret = tcp_ao_calc_key_sk(ao_key, traffic_key, sk, 1045 ao->lisn, ao->risn, true); 1046 if (ret) 1047 return ret; 1048 1049 traffic_key = rcv_other_key(ao_key); 1050 ret = tcp_ao_calc_key_sk(ao_key, traffic_key, sk, 1051 ao->lisn, ao->risn, false); 1052 return ret; 1053 } 1054 1055 void tcp_ao_connect_init(struct sock *sk) 1056 { 1057 struct tcp_sock *tp = tcp_sk(sk); 1058 struct tcp_ao_info *ao_info; 1059 union tcp_ao_addr *addr; 1060 struct tcp_ao_key *key; 1061 int family, l3index; 1062 1063 ao_info = rcu_dereference_protected(tp->ao_info, 1064 lockdep_sock_is_held(sk)); 1065 if (!ao_info) 1066 return; 1067 1068 /* Remove all keys that don't match the peer */ 1069 family = sk->sk_family; 1070 if (family == AF_INET) 1071 addr = (union tcp_ao_addr *)&sk->sk_daddr; 1072 #if IS_ENABLED(CONFIG_IPV6) 1073 else if (family == AF_INET6) 1074 addr = (union tcp_ao_addr *)&sk->sk_v6_daddr; 1075 #endif 1076 else 1077 return; 1078 l3index = l3mdev_master_ifindex_by_index(sock_net(sk), 1079 sk->sk_bound_dev_if); 1080 1081 hlist_for_each_entry_rcu(key, &ao_info->head, node) { 1082 if (!tcp_ao_key_cmp(key, l3index, addr, key->prefixlen, family, -1, -1)) 1083 continue; 1084 1085 if (key == ao_info->current_key) 1086 ao_info->current_key = NULL; 1087 if (key == ao_info->rnext_key) 1088 ao_info->rnext_key = NULL; 1089 hlist_del_rcu(&key->node); 1090 atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc); 1091 call_rcu(&key->rcu, tcp_ao_key_free_rcu); 1092 } 1093 1094 key = tp->af_specific->ao_lookup(sk, sk, -1, -1); 1095 if (key) { 1096 /* if current_key or rnext_key were not provided, 1097 * use the first key matching the peer 1098 */ 1099 if (!ao_info->current_key) 1100 ao_info->current_key = key; 1101 if (!ao_info->rnext_key) 1102 ao_info->rnext_key = key; 1103 tp->tcp_header_len += tcp_ao_len(key); 1104 1105 ao_info->lisn = htonl(tp->write_seq); 1106 ao_info->snd_sne = 0; 1107 } else { 1108 /* Can't happen: tcp_connect() verifies that there's 1109 * at least one tcp-ao key that matches the remote peer. 1110 */ 1111 WARN_ON_ONCE(1); 1112 rcu_assign_pointer(tp->ao_info, NULL); 1113 kfree(ao_info); 1114 } 1115 } 1116 1117 void tcp_ao_established(struct sock *sk) 1118 { 1119 struct tcp_ao_info *ao; 1120 struct tcp_ao_key *key; 1121 1122 ao = rcu_dereference_protected(tcp_sk(sk)->ao_info, 1123 lockdep_sock_is_held(sk)); 1124 if (!ao) 1125 return; 1126 1127 hlist_for_each_entry_rcu(key, &ao->head, node) 1128 tcp_ao_cache_traffic_keys(sk, ao, key); 1129 } 1130 1131 void tcp_ao_finish_connect(struct sock *sk, struct sk_buff *skb) 1132 { 1133 struct tcp_ao_info *ao; 1134 struct tcp_ao_key *key; 1135 1136 ao = rcu_dereference_protected(tcp_sk(sk)->ao_info, 1137 lockdep_sock_is_held(sk)); 1138 if (!ao) 1139 return; 1140 1141 WRITE_ONCE(ao->risn, tcp_hdr(skb)->seq); 1142 ao->rcv_sne = 0; 1143 1144 hlist_for_each_entry_rcu(key, &ao->head, node) 1145 tcp_ao_cache_traffic_keys(sk, ao, key); 1146 } 1147 1148 int tcp_ao_copy_all_matching(const struct sock *sk, struct sock *newsk, 1149 struct request_sock *req, struct sk_buff *skb, 1150 int family) 1151 { 1152 struct tcp_ao_key *key, *new_key, *first_key; 1153 struct tcp_ao_info *new_ao, *ao; 1154 struct hlist_node *key_head; 1155 int l3index, ret = -ENOMEM; 1156 union tcp_ao_addr *addr; 1157 bool match = false; 1158 1159 ao = rcu_dereference(tcp_sk(sk)->ao_info); 1160 if (!ao) 1161 return 0; 1162 1163 /* New socket without TCP-AO on it */ 1164 if (!tcp_rsk_used_ao(req)) 1165 return 0; 1166 1167 new_ao = tcp_ao_alloc_info(GFP_ATOMIC); 1168 if (!new_ao) 1169 return -ENOMEM; 1170 new_ao->lisn = htonl(tcp_rsk(req)->snt_isn); 1171 new_ao->risn = htonl(tcp_rsk(req)->rcv_isn); 1172 new_ao->ao_required = ao->ao_required; 1173 new_ao->accept_icmps = ao->accept_icmps; 1174 1175 if (family == AF_INET) { 1176 addr = (union tcp_ao_addr *)&newsk->sk_daddr; 1177 #if IS_ENABLED(CONFIG_IPV6) 1178 } else if (family == AF_INET6) { 1179 addr = (union tcp_ao_addr *)&newsk->sk_v6_daddr; 1180 #endif 1181 } else { 1182 ret = -EAFNOSUPPORT; 1183 goto free_ao; 1184 } 1185 l3index = l3mdev_master_ifindex_by_index(sock_net(newsk), 1186 newsk->sk_bound_dev_if); 1187 1188 hlist_for_each_entry_rcu(key, &ao->head, node) { 1189 if (tcp_ao_key_cmp(key, l3index, addr, key->prefixlen, family, -1, -1)) 1190 continue; 1191 1192 new_key = tcp_ao_copy_key(newsk, key); 1193 if (!new_key) 1194 goto free_and_exit; 1195 1196 tcp_ao_cache_traffic_keys(newsk, new_ao, new_key); 1197 tcp_ao_link_mkt(new_ao, new_key); 1198 match = true; 1199 } 1200 1201 if (!match) { 1202 /* RFC5925 (7.4.1) specifies that the TCP-AO status 1203 * of a connection is determined on the initial SYN. 1204 * At this point the connection was TCP-AO enabled, so 1205 * it can't switch to being unsigned if peer's key 1206 * disappears on the listening socket. 1207 */ 1208 ret = -EKEYREJECTED; 1209 goto free_and_exit; 1210 } 1211 1212 if (!static_key_fast_inc_not_disabled(&tcp_ao_needed.key.key)) { 1213 ret = -EUSERS; 1214 goto free_and_exit; 1215 } 1216 1217 key_head = rcu_dereference(hlist_first_rcu(&new_ao->head)); 1218 first_key = hlist_entry_safe(key_head, struct tcp_ao_key, node); 1219 1220 key = tcp_ao_established_key(new_ao, tcp_rsk(req)->ao_keyid, -1); 1221 if (key) 1222 new_ao->current_key = key; 1223 else 1224 new_ao->current_key = first_key; 1225 1226 /* set rnext_key */ 1227 key = tcp_ao_established_key(new_ao, -1, tcp_rsk(req)->ao_rcv_next); 1228 if (key) 1229 new_ao->rnext_key = key; 1230 else 1231 new_ao->rnext_key = first_key; 1232 1233 sk_gso_disable(newsk); 1234 rcu_assign_pointer(tcp_sk(newsk)->ao_info, new_ao); 1235 1236 return 0; 1237 1238 free_and_exit: 1239 hlist_for_each_entry_safe(key, key_head, &new_ao->head, node) { 1240 hlist_del(&key->node); 1241 tcp_sigpool_release(key->tcp_sigpool_id); 1242 atomic_sub(tcp_ao_sizeof_key(key), &newsk->sk_omem_alloc); 1243 kfree_sensitive(key); 1244 } 1245 free_ao: 1246 kfree(new_ao); 1247 return ret; 1248 } 1249 1250 static bool tcp_ao_can_set_current_rnext(struct sock *sk) 1251 { 1252 /* There aren't current/rnext keys on TCP_LISTEN sockets */ 1253 if (sk->sk_state == TCP_LISTEN) 1254 return false; 1255 return true; 1256 } 1257 1258 static int tcp_ao_verify_ipv4(struct sock *sk, struct tcp_ao_add *cmd, 1259 union tcp_ao_addr **addr) 1260 { 1261 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd->addr; 1262 struct inet_sock *inet = inet_sk(sk); 1263 1264 if (sin->sin_family != AF_INET) 1265 return -EINVAL; 1266 1267 /* Currently matching is not performed on port (or port ranges) */ 1268 if (sin->sin_port != 0) 1269 return -EINVAL; 1270 1271 /* Check prefix and trailing 0's in addr */ 1272 if (cmd->prefix != 0) { 1273 __be32 mask; 1274 1275 if (ntohl(sin->sin_addr.s_addr) == INADDR_ANY) 1276 return -EINVAL; 1277 if (cmd->prefix > 32) 1278 return -EINVAL; 1279 1280 mask = inet_make_mask(cmd->prefix); 1281 if (sin->sin_addr.s_addr & ~mask) 1282 return -EINVAL; 1283 1284 /* Check that MKT address is consistent with socket */ 1285 if (ntohl(inet->inet_daddr) != INADDR_ANY && 1286 (inet->inet_daddr & mask) != sin->sin_addr.s_addr) 1287 return -EINVAL; 1288 } else { 1289 if (ntohl(sin->sin_addr.s_addr) != INADDR_ANY) 1290 return -EINVAL; 1291 } 1292 1293 *addr = (union tcp_ao_addr *)&sin->sin_addr; 1294 return 0; 1295 } 1296 1297 static int tcp_ao_parse_crypto(struct tcp_ao_add *cmd, struct tcp_ao_key *key) 1298 { 1299 unsigned int syn_tcp_option_space; 1300 bool is_kdf_aes_128_cmac = false; 1301 struct crypto_ahash *tfm; 1302 struct tcp_sigpool hp; 1303 void *tmp_key = NULL; 1304 int err; 1305 1306 /* RFC5926, 3.1.1.2. KDF_AES_128_CMAC */ 1307 if (!strcmp("cmac(aes128)", cmd->alg_name)) { 1308 strscpy(cmd->alg_name, "cmac(aes)", sizeof(cmd->alg_name)); 1309 is_kdf_aes_128_cmac = (cmd->keylen != 16); 1310 tmp_key = kmalloc(cmd->keylen, GFP_KERNEL); 1311 if (!tmp_key) 1312 return -ENOMEM; 1313 } 1314 1315 key->maclen = cmd->maclen ?: 12; /* 12 is the default in RFC5925 */ 1316 1317 /* Check: maclen + tcp-ao header <= (MAX_TCP_OPTION_SPACE - mss 1318 * - tstamp - wscale - sackperm), 1319 * see tcp_syn_options(), tcp_synack_options(), commit 33ad798c924b. 1320 * 1321 * In order to allow D-SACK with TCP-AO, the header size should be: 1322 * (MAX_TCP_OPTION_SPACE - TCPOLEN_TSTAMP_ALIGNED 1323 * - TCPOLEN_SACK_BASE_ALIGNED 1324 * - 2 * TCPOLEN_SACK_PERBLOCK) = 8 (maclen = 4), 1325 * see tcp_established_options(). 1326 * 1327 * RFC5925, 2.2: 1328 * Typical MACs are 96-128 bits (12-16 bytes), but any length 1329 * that fits in the header of the segment being authenticated 1330 * is allowed. 1331 * 1332 * RFC5925, 7.6: 1333 * TCP-AO continues to consume 16 bytes in non-SYN segments, 1334 * leaving a total of 24 bytes for other options, of which 1335 * the timestamp consumes 10. This leaves 14 bytes, of which 10 1336 * are used for a single SACK block. When two SACK blocks are used, 1337 * such as to handle D-SACK, a smaller TCP-AO MAC would be required 1338 * to make room for the additional SACK block (i.e., to leave 18 1339 * bytes for the D-SACK variant of the SACK option) [RFC2883]. 1340 * Note that D-SACK is not supportable in TCP MD5 in the presence 1341 * of timestamps, because TCP MD5’s MAC length is fixed and too 1342 * large to leave sufficient option space. 1343 */ 1344 syn_tcp_option_space = MAX_TCP_OPTION_SPACE; 1345 syn_tcp_option_space -= TCPOLEN_TSTAMP_ALIGNED; 1346 syn_tcp_option_space -= TCPOLEN_WSCALE_ALIGNED; 1347 syn_tcp_option_space -= TCPOLEN_SACKPERM_ALIGNED; 1348 if (tcp_ao_len(key) > syn_tcp_option_space) { 1349 err = -EMSGSIZE; 1350 goto err_kfree; 1351 } 1352 1353 key->keylen = cmd->keylen; 1354 memcpy(key->key, cmd->key, cmd->keylen); 1355 1356 err = tcp_sigpool_start(key->tcp_sigpool_id, &hp); 1357 if (err) 1358 goto err_kfree; 1359 1360 tfm = crypto_ahash_reqtfm(hp.req); 1361 if (is_kdf_aes_128_cmac) { 1362 void *scratch = hp.scratch; 1363 struct scatterlist sg; 1364 1365 memcpy(tmp_key, cmd->key, cmd->keylen); 1366 sg_init_one(&sg, tmp_key, cmd->keylen); 1367 1368 /* Using zero-key of 16 bytes as described in RFC5926 */ 1369 memset(scratch, 0, 16); 1370 err = crypto_ahash_setkey(tfm, scratch, 16); 1371 if (err) 1372 goto err_pool_end; 1373 1374 err = crypto_ahash_init(hp.req); 1375 if (err) 1376 goto err_pool_end; 1377 1378 ahash_request_set_crypt(hp.req, &sg, key->key, cmd->keylen); 1379 err = crypto_ahash_update(hp.req); 1380 if (err) 1381 goto err_pool_end; 1382 1383 err |= crypto_ahash_final(hp.req); 1384 if (err) 1385 goto err_pool_end; 1386 key->keylen = 16; 1387 } 1388 1389 err = crypto_ahash_setkey(tfm, key->key, key->keylen); 1390 if (err) 1391 goto err_pool_end; 1392 1393 tcp_sigpool_end(&hp); 1394 kfree_sensitive(tmp_key); 1395 1396 if (tcp_ao_maclen(key) > key->digest_size) 1397 return -EINVAL; 1398 1399 return 0; 1400 1401 err_pool_end: 1402 tcp_sigpool_end(&hp); 1403 err_kfree: 1404 kfree_sensitive(tmp_key); 1405 return err; 1406 } 1407 1408 #if IS_ENABLED(CONFIG_IPV6) 1409 static int tcp_ao_verify_ipv6(struct sock *sk, struct tcp_ao_add *cmd, 1410 union tcp_ao_addr **paddr, 1411 unsigned short int *family) 1412 { 1413 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd->addr; 1414 struct in6_addr *addr = &sin6->sin6_addr; 1415 u8 prefix = cmd->prefix; 1416 1417 if (sin6->sin6_family != AF_INET6) 1418 return -EINVAL; 1419 1420 /* Currently matching is not performed on port (or port ranges) */ 1421 if (sin6->sin6_port != 0) 1422 return -EINVAL; 1423 1424 /* Check prefix and trailing 0's in addr */ 1425 if (cmd->prefix != 0 && ipv6_addr_v4mapped(addr)) { 1426 __be32 addr4 = addr->s6_addr32[3]; 1427 __be32 mask; 1428 1429 if (prefix > 32 || ntohl(addr4) == INADDR_ANY) 1430 return -EINVAL; 1431 1432 mask = inet_make_mask(prefix); 1433 if (addr4 & ~mask) 1434 return -EINVAL; 1435 1436 /* Check that MKT address is consistent with socket */ 1437 if (!ipv6_addr_any(&sk->sk_v6_daddr)) { 1438 __be32 daddr4 = sk->sk_v6_daddr.s6_addr32[3]; 1439 1440 if (!ipv6_addr_v4mapped(&sk->sk_v6_daddr)) 1441 return -EINVAL; 1442 if ((daddr4 & mask) != addr4) 1443 return -EINVAL; 1444 } 1445 1446 *paddr = (union tcp_ao_addr *)&addr->s6_addr32[3]; 1447 *family = AF_INET; 1448 return 0; 1449 } else if (cmd->prefix != 0) { 1450 struct in6_addr pfx; 1451 1452 if (ipv6_addr_any(addr) || prefix > 128) 1453 return -EINVAL; 1454 1455 ipv6_addr_prefix(&pfx, addr, prefix); 1456 if (ipv6_addr_cmp(&pfx, addr)) 1457 return -EINVAL; 1458 1459 /* Check that MKT address is consistent with socket */ 1460 if (!ipv6_addr_any(&sk->sk_v6_daddr) && 1461 !ipv6_prefix_equal(&sk->sk_v6_daddr, addr, prefix)) 1462 1463 return -EINVAL; 1464 } else { 1465 if (!ipv6_addr_any(addr)) 1466 return -EINVAL; 1467 } 1468 1469 *paddr = (union tcp_ao_addr *)addr; 1470 return 0; 1471 } 1472 #else 1473 static int tcp_ao_verify_ipv6(struct sock *sk, struct tcp_ao_add *cmd, 1474 union tcp_ao_addr **paddr, 1475 unsigned short int *family) 1476 { 1477 return -EOPNOTSUPP; 1478 } 1479 #endif 1480 1481 static struct tcp_ao_info *setsockopt_ao_info(struct sock *sk) 1482 { 1483 if (sk_fullsock(sk)) { 1484 return rcu_dereference_protected(tcp_sk(sk)->ao_info, 1485 lockdep_sock_is_held(sk)); 1486 } else if (sk->sk_state == TCP_TIME_WAIT) { 1487 return rcu_dereference_protected(tcp_twsk(sk)->ao_info, 1488 lockdep_sock_is_held(sk)); 1489 } 1490 return ERR_PTR(-ESOCKTNOSUPPORT); 1491 } 1492 1493 static struct tcp_ao_info *getsockopt_ao_info(struct sock *sk) 1494 { 1495 if (sk_fullsock(sk)) 1496 return rcu_dereference(tcp_sk(sk)->ao_info); 1497 else if (sk->sk_state == TCP_TIME_WAIT) 1498 return rcu_dereference(tcp_twsk(sk)->ao_info); 1499 1500 return ERR_PTR(-ESOCKTNOSUPPORT); 1501 } 1502 1503 #define TCP_AO_KEYF_ALL (TCP_AO_KEYF_IFINDEX | TCP_AO_KEYF_EXCLUDE_OPT) 1504 #define TCP_AO_GET_KEYF_VALID (TCP_AO_KEYF_IFINDEX) 1505 1506 static struct tcp_ao_key *tcp_ao_key_alloc(struct sock *sk, 1507 struct tcp_ao_add *cmd) 1508 { 1509 const char *algo = cmd->alg_name; 1510 unsigned int digest_size; 1511 struct crypto_ahash *tfm; 1512 struct tcp_ao_key *key; 1513 struct tcp_sigpool hp; 1514 int err, pool_id; 1515 size_t size; 1516 1517 /* Force null-termination of alg_name */ 1518 cmd->alg_name[ARRAY_SIZE(cmd->alg_name) - 1] = '\0'; 1519 1520 /* RFC5926, 3.1.1.2. KDF_AES_128_CMAC */ 1521 if (!strcmp("cmac(aes128)", algo)) 1522 algo = "cmac(aes)"; 1523 1524 /* Full TCP header (th->doff << 2) should fit into scratch area, 1525 * see tcp_ao_hash_header(). 1526 */ 1527 pool_id = tcp_sigpool_alloc_ahash(algo, 60); 1528 if (pool_id < 0) 1529 return ERR_PTR(pool_id); 1530 1531 err = tcp_sigpool_start(pool_id, &hp); 1532 if (err) 1533 goto err_free_pool; 1534 1535 tfm = crypto_ahash_reqtfm(hp.req); 1536 if (crypto_ahash_alignmask(tfm) > TCP_AO_KEY_ALIGN) { 1537 err = -EOPNOTSUPP; 1538 goto err_pool_end; 1539 } 1540 digest_size = crypto_ahash_digestsize(tfm); 1541 tcp_sigpool_end(&hp); 1542 1543 size = sizeof(struct tcp_ao_key) + (digest_size << 1); 1544 key = sock_kmalloc(sk, size, GFP_KERNEL); 1545 if (!key) { 1546 err = -ENOMEM; 1547 goto err_free_pool; 1548 } 1549 1550 key->tcp_sigpool_id = pool_id; 1551 key->digest_size = digest_size; 1552 return key; 1553 1554 err_pool_end: 1555 tcp_sigpool_end(&hp); 1556 err_free_pool: 1557 tcp_sigpool_release(pool_id); 1558 return ERR_PTR(err); 1559 } 1560 1561 static int tcp_ao_add_cmd(struct sock *sk, unsigned short int family, 1562 sockptr_t optval, int optlen) 1563 { 1564 struct tcp_ao_info *ao_info; 1565 union tcp_ao_addr *addr; 1566 struct tcp_ao_key *key; 1567 struct tcp_ao_add cmd; 1568 int ret, l3index = 0; 1569 bool first = false; 1570 1571 if (optlen < sizeof(cmd)) 1572 return -EINVAL; 1573 1574 ret = copy_struct_from_sockptr(&cmd, sizeof(cmd), optval, optlen); 1575 if (ret) 1576 return ret; 1577 1578 if (cmd.keylen > TCP_AO_MAXKEYLEN) 1579 return -EINVAL; 1580 1581 if (cmd.reserved != 0 || cmd.reserved2 != 0) 1582 return -EINVAL; 1583 1584 if (family == AF_INET) 1585 ret = tcp_ao_verify_ipv4(sk, &cmd, &addr); 1586 else 1587 ret = tcp_ao_verify_ipv6(sk, &cmd, &addr, &family); 1588 if (ret) 1589 return ret; 1590 1591 if (cmd.keyflags & ~TCP_AO_KEYF_ALL) 1592 return -EINVAL; 1593 1594 if (cmd.set_current || cmd.set_rnext) { 1595 if (!tcp_ao_can_set_current_rnext(sk)) 1596 return -EINVAL; 1597 } 1598 1599 if (cmd.ifindex && !(cmd.keyflags & TCP_AO_KEYF_IFINDEX)) 1600 return -EINVAL; 1601 1602 /* For cmd.tcp_ifindex = 0 the key will apply to the default VRF */ 1603 if (cmd.keyflags & TCP_AO_KEYF_IFINDEX && cmd.ifindex) { 1604 int bound_dev_if = READ_ONCE(sk->sk_bound_dev_if); 1605 struct net_device *dev; 1606 1607 rcu_read_lock(); 1608 dev = dev_get_by_index_rcu(sock_net(sk), cmd.ifindex); 1609 if (dev && netif_is_l3_master(dev)) 1610 l3index = dev->ifindex; 1611 rcu_read_unlock(); 1612 1613 if (!dev || !l3index) 1614 return -EINVAL; 1615 1616 /* It's still possible to bind after adding keys or even 1617 * re-bind to a different dev (with CAP_NET_RAW). 1618 * So, no reason to return error here, rather try to be 1619 * nice and warn the user. 1620 */ 1621 if (bound_dev_if && bound_dev_if != cmd.ifindex) 1622 net_warn_ratelimited("AO key ifindex %d != sk bound ifindex %d\n", 1623 cmd.ifindex, bound_dev_if); 1624 } 1625 1626 /* Don't allow keys for peers that have a matching TCP-MD5 key */ 1627 if (cmd.keyflags & TCP_AO_KEYF_IFINDEX) { 1628 /* Non-_exact version of tcp_md5_do_lookup() will 1629 * as well match keys that aren't bound to a specific VRF 1630 * (that will make them match AO key with 1631 * sysctl_tcp_l3dev_accept = 1 1632 */ 1633 if (tcp_md5_do_lookup(sk, l3index, addr, family)) 1634 return -EKEYREJECTED; 1635 } else { 1636 if (tcp_md5_do_lookup_any_l3index(sk, addr, family)) 1637 return -EKEYREJECTED; 1638 } 1639 1640 ao_info = setsockopt_ao_info(sk); 1641 if (IS_ERR(ao_info)) 1642 return PTR_ERR(ao_info); 1643 1644 if (!ao_info) { 1645 ao_info = tcp_ao_alloc_info(GFP_KERNEL); 1646 if (!ao_info) 1647 return -ENOMEM; 1648 first = true; 1649 } else { 1650 /* Check that neither RecvID nor SendID match any 1651 * existing key for the peer, RFC5925 3.1: 1652 * > The IDs of MKTs MUST NOT overlap where their 1653 * > TCP connection identifiers overlap. 1654 */ 1655 if (__tcp_ao_do_lookup(sk, l3index, addr, family, cmd.prefix, -1, cmd.rcvid)) 1656 return -EEXIST; 1657 if (__tcp_ao_do_lookup(sk, l3index, addr, family, 1658 cmd.prefix, cmd.sndid, -1)) 1659 return -EEXIST; 1660 } 1661 1662 key = tcp_ao_key_alloc(sk, &cmd); 1663 if (IS_ERR(key)) { 1664 ret = PTR_ERR(key); 1665 goto err_free_ao; 1666 } 1667 1668 INIT_HLIST_NODE(&key->node); 1669 memcpy(&key->addr, addr, (family == AF_INET) ? sizeof(struct in_addr) : 1670 sizeof(struct in6_addr)); 1671 key->prefixlen = cmd.prefix; 1672 key->family = family; 1673 key->keyflags = cmd.keyflags; 1674 key->sndid = cmd.sndid; 1675 key->rcvid = cmd.rcvid; 1676 key->l3index = l3index; 1677 atomic64_set(&key->pkt_good, 0); 1678 atomic64_set(&key->pkt_bad, 0); 1679 1680 ret = tcp_ao_parse_crypto(&cmd, key); 1681 if (ret < 0) 1682 goto err_free_sock; 1683 1684 if (!((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))) { 1685 tcp_ao_cache_traffic_keys(sk, ao_info, key); 1686 if (first) { 1687 ao_info->current_key = key; 1688 ao_info->rnext_key = key; 1689 } 1690 } 1691 1692 tcp_ao_link_mkt(ao_info, key); 1693 if (first) { 1694 if (!static_branch_inc(&tcp_ao_needed.key)) { 1695 ret = -EUSERS; 1696 goto err_free_sock; 1697 } 1698 sk_gso_disable(sk); 1699 rcu_assign_pointer(tcp_sk(sk)->ao_info, ao_info); 1700 } 1701 1702 if (cmd.set_current) 1703 WRITE_ONCE(ao_info->current_key, key); 1704 if (cmd.set_rnext) 1705 WRITE_ONCE(ao_info->rnext_key, key); 1706 return 0; 1707 1708 err_free_sock: 1709 atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc); 1710 tcp_sigpool_release(key->tcp_sigpool_id); 1711 kfree_sensitive(key); 1712 err_free_ao: 1713 if (first) 1714 kfree(ao_info); 1715 return ret; 1716 } 1717 1718 static int tcp_ao_delete_key(struct sock *sk, struct tcp_ao_info *ao_info, 1719 bool del_async, struct tcp_ao_key *key, 1720 struct tcp_ao_key *new_current, 1721 struct tcp_ao_key *new_rnext) 1722 { 1723 int err; 1724 1725 hlist_del_rcu(&key->node); 1726 1727 /* Support for async delete on listening sockets: as they don't 1728 * need current_key/rnext_key maintaining, we don't need to check 1729 * them and we can just free all resources in RCU fashion. 1730 */ 1731 if (del_async) { 1732 atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc); 1733 call_rcu(&key->rcu, tcp_ao_key_free_rcu); 1734 return 0; 1735 } 1736 1737 /* At this moment another CPU could have looked this key up 1738 * while it was unlinked from the list. Wait for RCU grace period, 1739 * after which the key is off-list and can't be looked up again; 1740 * the rx path [just before RCU came] might have used it and set it 1741 * as current_key (very unlikely). 1742 * Free the key with next RCU grace period (in case it was 1743 * current_key before tcp_ao_current_rnext() might have 1744 * changed it in forced-delete). 1745 */ 1746 synchronize_rcu(); 1747 if (new_current) 1748 WRITE_ONCE(ao_info->current_key, new_current); 1749 if (new_rnext) 1750 WRITE_ONCE(ao_info->rnext_key, new_rnext); 1751 1752 if (unlikely(READ_ONCE(ao_info->current_key) == key || 1753 READ_ONCE(ao_info->rnext_key) == key)) { 1754 err = -EBUSY; 1755 goto add_key; 1756 } 1757 1758 atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc); 1759 call_rcu(&key->rcu, tcp_ao_key_free_rcu); 1760 1761 return 0; 1762 add_key: 1763 hlist_add_head_rcu(&key->node, &ao_info->head); 1764 return err; 1765 } 1766 1767 #define TCP_AO_DEL_KEYF_ALL (TCP_AO_KEYF_IFINDEX) 1768 static int tcp_ao_del_cmd(struct sock *sk, unsigned short int family, 1769 sockptr_t optval, int optlen) 1770 { 1771 struct tcp_ao_key *key, *new_current = NULL, *new_rnext = NULL; 1772 int err, addr_len, l3index = 0; 1773 struct tcp_ao_info *ao_info; 1774 union tcp_ao_addr *addr; 1775 struct tcp_ao_del cmd; 1776 __u8 prefix; 1777 u16 port; 1778 1779 if (optlen < sizeof(cmd)) 1780 return -EINVAL; 1781 1782 err = copy_struct_from_sockptr(&cmd, sizeof(cmd), optval, optlen); 1783 if (err) 1784 return err; 1785 1786 if (cmd.reserved != 0 || cmd.reserved2 != 0) 1787 return -EINVAL; 1788 1789 if (cmd.set_current || cmd.set_rnext) { 1790 if (!tcp_ao_can_set_current_rnext(sk)) 1791 return -EINVAL; 1792 } 1793 1794 if (cmd.keyflags & ~TCP_AO_DEL_KEYF_ALL) 1795 return -EINVAL; 1796 1797 /* No sanity check for TCP_AO_KEYF_IFINDEX as if a VRF 1798 * was destroyed, there still should be a way to delete keys, 1799 * that were bound to that l3intf. So, fail late at lookup stage 1800 * if there is no key for that ifindex. 1801 */ 1802 if (cmd.ifindex && !(cmd.keyflags & TCP_AO_KEYF_IFINDEX)) 1803 return -EINVAL; 1804 1805 ao_info = setsockopt_ao_info(sk); 1806 if (IS_ERR(ao_info)) 1807 return PTR_ERR(ao_info); 1808 if (!ao_info) 1809 return -ENOENT; 1810 1811 /* For sockets in TCP_CLOSED it's possible set keys that aren't 1812 * matching the future peer (address/VRF/etc), 1813 * tcp_ao_connect_init() will choose a correct matching MKT 1814 * if there's any. 1815 */ 1816 if (cmd.set_current) { 1817 new_current = tcp_ao_established_key(ao_info, cmd.current_key, -1); 1818 if (!new_current) 1819 return -ENOENT; 1820 } 1821 if (cmd.set_rnext) { 1822 new_rnext = tcp_ao_established_key(ao_info, -1, cmd.rnext); 1823 if (!new_rnext) 1824 return -ENOENT; 1825 } 1826 if (cmd.del_async && sk->sk_state != TCP_LISTEN) 1827 return -EINVAL; 1828 1829 if (family == AF_INET) { 1830 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.addr; 1831 1832 addr = (union tcp_ao_addr *)&sin->sin_addr; 1833 addr_len = sizeof(struct in_addr); 1834 port = ntohs(sin->sin_port); 1835 } else { 1836 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.addr; 1837 struct in6_addr *addr6 = &sin6->sin6_addr; 1838 1839 if (ipv6_addr_v4mapped(addr6)) { 1840 addr = (union tcp_ao_addr *)&addr6->s6_addr32[3]; 1841 addr_len = sizeof(struct in_addr); 1842 family = AF_INET; 1843 } else { 1844 addr = (union tcp_ao_addr *)addr6; 1845 addr_len = sizeof(struct in6_addr); 1846 } 1847 port = ntohs(sin6->sin6_port); 1848 } 1849 prefix = cmd.prefix; 1850 1851 /* Currently matching is not performed on port (or port ranges) */ 1852 if (port != 0) 1853 return -EINVAL; 1854 1855 /* We could choose random present key here for current/rnext 1856 * but that's less predictable. Let's be strict and don't 1857 * allow removing a key that's in use. RFC5925 doesn't 1858 * specify how-to coordinate key removal, but says: 1859 * "It is presumed that an MKT affecting a particular 1860 * connection cannot be destroyed during an active connection" 1861 */ 1862 hlist_for_each_entry_rcu(key, &ao_info->head, node) { 1863 if (cmd.sndid != key->sndid || 1864 cmd.rcvid != key->rcvid) 1865 continue; 1866 1867 if (family != key->family || 1868 prefix != key->prefixlen || 1869 memcmp(addr, &key->addr, addr_len)) 1870 continue; 1871 1872 if ((cmd.keyflags & TCP_AO_KEYF_IFINDEX) != 1873 (key->keyflags & TCP_AO_KEYF_IFINDEX)) 1874 continue; 1875 1876 if (key->l3index != l3index) 1877 continue; 1878 1879 if (key == new_current || key == new_rnext) 1880 continue; 1881 1882 return tcp_ao_delete_key(sk, ao_info, cmd.del_async, key, 1883 new_current, new_rnext); 1884 } 1885 return -ENOENT; 1886 } 1887 1888 /* cmd.ao_required makes a socket TCP-AO only. 1889 * Don't allow any md5 keys for any l3intf on the socket together with it. 1890 * Restricting it early in setsockopt() removes a check for 1891 * ao_info->ao_required on inbound tcp segment fast-path. 1892 */ 1893 static int tcp_ao_required_verify(struct sock *sk) 1894 { 1895 #ifdef CONFIG_TCP_MD5SIG 1896 const struct tcp_md5sig_info *md5sig; 1897 1898 if (!static_branch_unlikely(&tcp_md5_needed.key)) 1899 return 0; 1900 1901 md5sig = rcu_dereference_check(tcp_sk(sk)->md5sig_info, 1902 lockdep_sock_is_held(sk)); 1903 if (!md5sig) 1904 return 0; 1905 1906 if (rcu_dereference_check(hlist_first_rcu(&md5sig->head), 1907 lockdep_sock_is_held(sk))) 1908 return 1; 1909 #endif 1910 return 0; 1911 } 1912 1913 static int tcp_ao_info_cmd(struct sock *sk, unsigned short int family, 1914 sockptr_t optval, int optlen) 1915 { 1916 struct tcp_ao_key *new_current = NULL, *new_rnext = NULL; 1917 struct tcp_ao_info *ao_info; 1918 struct tcp_ao_info_opt cmd; 1919 bool first = false; 1920 int err; 1921 1922 if (optlen < sizeof(cmd)) 1923 return -EINVAL; 1924 1925 err = copy_struct_from_sockptr(&cmd, sizeof(cmd), optval, optlen); 1926 if (err) 1927 return err; 1928 1929 if (cmd.set_current || cmd.set_rnext) { 1930 if (!tcp_ao_can_set_current_rnext(sk)) 1931 return -EINVAL; 1932 } 1933 1934 if (cmd.reserved != 0 || cmd.reserved2 != 0) 1935 return -EINVAL; 1936 1937 ao_info = setsockopt_ao_info(sk); 1938 if (IS_ERR(ao_info)) 1939 return PTR_ERR(ao_info); 1940 if (!ao_info) { 1941 if (!((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))) 1942 return -EINVAL; 1943 ao_info = tcp_ao_alloc_info(GFP_KERNEL); 1944 if (!ao_info) 1945 return -ENOMEM; 1946 first = true; 1947 } 1948 1949 if (cmd.ao_required && tcp_ao_required_verify(sk)) 1950 return -EKEYREJECTED; 1951 1952 /* For sockets in TCP_CLOSED it's possible set keys that aren't 1953 * matching the future peer (address/port/VRF/etc), 1954 * tcp_ao_connect_init() will choose a correct matching MKT 1955 * if there's any. 1956 */ 1957 if (cmd.set_current) { 1958 new_current = tcp_ao_established_key(ao_info, cmd.current_key, -1); 1959 if (!new_current) { 1960 err = -ENOENT; 1961 goto out; 1962 } 1963 } 1964 if (cmd.set_rnext) { 1965 new_rnext = tcp_ao_established_key(ao_info, -1, cmd.rnext); 1966 if (!new_rnext) { 1967 err = -ENOENT; 1968 goto out; 1969 } 1970 } 1971 if (cmd.set_counters) { 1972 atomic64_set(&ao_info->counters.pkt_good, cmd.pkt_good); 1973 atomic64_set(&ao_info->counters.pkt_bad, cmd.pkt_bad); 1974 atomic64_set(&ao_info->counters.key_not_found, cmd.pkt_key_not_found); 1975 atomic64_set(&ao_info->counters.ao_required, cmd.pkt_ao_required); 1976 atomic64_set(&ao_info->counters.dropped_icmp, cmd.pkt_dropped_icmp); 1977 } 1978 1979 ao_info->ao_required = cmd.ao_required; 1980 ao_info->accept_icmps = cmd.accept_icmps; 1981 if (new_current) 1982 WRITE_ONCE(ao_info->current_key, new_current); 1983 if (new_rnext) 1984 WRITE_ONCE(ao_info->rnext_key, new_rnext); 1985 if (first) { 1986 if (!static_branch_inc(&tcp_ao_needed.key)) { 1987 err = -EUSERS; 1988 goto out; 1989 } 1990 sk_gso_disable(sk); 1991 rcu_assign_pointer(tcp_sk(sk)->ao_info, ao_info); 1992 } 1993 return 0; 1994 out: 1995 if (first) 1996 kfree(ao_info); 1997 return err; 1998 } 1999 2000 int tcp_parse_ao(struct sock *sk, int cmd, unsigned short int family, 2001 sockptr_t optval, int optlen) 2002 { 2003 if (WARN_ON_ONCE(family != AF_INET && family != AF_INET6)) 2004 return -EAFNOSUPPORT; 2005 2006 switch (cmd) { 2007 case TCP_AO_ADD_KEY: 2008 return tcp_ao_add_cmd(sk, family, optval, optlen); 2009 case TCP_AO_DEL_KEY: 2010 return tcp_ao_del_cmd(sk, family, optval, optlen); 2011 case TCP_AO_INFO: 2012 return tcp_ao_info_cmd(sk, family, optval, optlen); 2013 default: 2014 WARN_ON_ONCE(1); 2015 return -EINVAL; 2016 } 2017 } 2018 2019 int tcp_v4_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen) 2020 { 2021 return tcp_parse_ao(sk, cmd, AF_INET, optval, optlen); 2022 } 2023 2024 /* tcp_ao_copy_mkts_to_user(ao_info, optval, optlen) 2025 * 2026 * @ao_info: struct tcp_ao_info on the socket that 2027 * socket getsockopt(TCP_AO_GET_KEYS) is executed on 2028 * @optval: pointer to array of tcp_ao_getsockopt structures in user space. 2029 * Must be != NULL. 2030 * @optlen: pointer to size of tcp_ao_getsockopt structure. 2031 * Must be != NULL. 2032 * 2033 * Return value: 0 on success, a negative error number otherwise. 2034 * 2035 * optval points to an array of tcp_ao_getsockopt structures in user space. 2036 * optval[0] is used as both input and output to getsockopt. It determines 2037 * which keys are returned by the kernel. 2038 * optval[0].nkeys is the size of the array in user space. On return it contains 2039 * the number of keys matching the search criteria. 2040 * If tcp_ao_getsockopt::get_all is set, then all keys in the socket are 2041 * returned, otherwise only keys matching <addr, prefix, sndid, rcvid> 2042 * in optval[0] are returned. 2043 * optlen is also used as both input and output. The user provides the size 2044 * of struct tcp_ao_getsockopt in user space, and the kernel returns the size 2045 * of the structure in kernel space. 2046 * The size of struct tcp_ao_getsockopt may differ between user and kernel. 2047 * There are three cases to consider: 2048 * * If usize == ksize, then keys are copied verbatim. 2049 * * If usize < ksize, then the userspace has passed an old struct to a 2050 * newer kernel. The rest of the trailing bytes in optval[0] 2051 * (ksize - usize) are interpreted as 0 by the kernel. 2052 * * If usize > ksize, then the userspace has passed a new struct to an 2053 * older kernel. The trailing bytes unknown to the kernel (usize - ksize) 2054 * are checked to ensure they are zeroed, otherwise -E2BIG is returned. 2055 * On return the kernel fills in min(usize, ksize) in each entry of the array. 2056 * The layout of the fields in the user and kernel structures is expected to 2057 * be the same (including in the 32bit vs 64bit case). 2058 */ 2059 static int tcp_ao_copy_mkts_to_user(struct tcp_ao_info *ao_info, 2060 sockptr_t optval, sockptr_t optlen) 2061 { 2062 struct tcp_ao_getsockopt opt_in, opt_out; 2063 struct tcp_ao_key *key, *current_key; 2064 bool do_address_matching = true; 2065 union tcp_ao_addr *addr = NULL; 2066 int err, l3index, user_len; 2067 unsigned int max_keys; /* maximum number of keys to copy to user */ 2068 size_t out_offset = 0; 2069 size_t bytes_to_write; /* number of bytes to write to user level */ 2070 u32 matched_keys; /* keys from ao_info matched so far */ 2071 int optlen_out; 2072 __be16 port = 0; 2073 2074 if (copy_from_sockptr(&user_len, optlen, sizeof(int))) 2075 return -EFAULT; 2076 2077 if (user_len <= 0) 2078 return -EINVAL; 2079 2080 memset(&opt_in, 0, sizeof(struct tcp_ao_getsockopt)); 2081 err = copy_struct_from_sockptr(&opt_in, sizeof(opt_in), 2082 optval, user_len); 2083 if (err < 0) 2084 return err; 2085 2086 if (opt_in.pkt_good || opt_in.pkt_bad) 2087 return -EINVAL; 2088 if (opt_in.keyflags & ~TCP_AO_GET_KEYF_VALID) 2089 return -EINVAL; 2090 if (opt_in.ifindex && !(opt_in.keyflags & TCP_AO_KEYF_IFINDEX)) 2091 return -EINVAL; 2092 2093 if (opt_in.reserved != 0) 2094 return -EINVAL; 2095 2096 max_keys = opt_in.nkeys; 2097 l3index = (opt_in.keyflags & TCP_AO_KEYF_IFINDEX) ? opt_in.ifindex : -1; 2098 2099 if (opt_in.get_all || opt_in.is_current || opt_in.is_rnext) { 2100 if (opt_in.get_all && (opt_in.is_current || opt_in.is_rnext)) 2101 return -EINVAL; 2102 do_address_matching = false; 2103 } 2104 2105 switch (opt_in.addr.ss_family) { 2106 case AF_INET: { 2107 struct sockaddr_in *sin; 2108 __be32 mask; 2109 2110 sin = (struct sockaddr_in *)&opt_in.addr; 2111 port = sin->sin_port; 2112 addr = (union tcp_ao_addr *)&sin->sin_addr; 2113 2114 if (opt_in.prefix > 32) 2115 return -EINVAL; 2116 2117 if (ntohl(sin->sin_addr.s_addr) == INADDR_ANY && 2118 opt_in.prefix != 0) 2119 return -EINVAL; 2120 2121 mask = inet_make_mask(opt_in.prefix); 2122 if (sin->sin_addr.s_addr & ~mask) 2123 return -EINVAL; 2124 2125 break; 2126 } 2127 case AF_INET6: { 2128 struct sockaddr_in6 *sin6; 2129 struct in6_addr *addr6; 2130 2131 sin6 = (struct sockaddr_in6 *)&opt_in.addr; 2132 addr = (union tcp_ao_addr *)&sin6->sin6_addr; 2133 addr6 = &sin6->sin6_addr; 2134 port = sin6->sin6_port; 2135 2136 /* We don't have to change family and @addr here if 2137 * ipv6_addr_v4mapped() like in key adding: 2138 * tcp_ao_key_cmp() does it. Do the sanity checks though. 2139 */ 2140 if (opt_in.prefix != 0) { 2141 if (ipv6_addr_v4mapped(addr6)) { 2142 __be32 mask, addr4 = addr6->s6_addr32[3]; 2143 2144 if (opt_in.prefix > 32 || 2145 ntohl(addr4) == INADDR_ANY) 2146 return -EINVAL; 2147 mask = inet_make_mask(opt_in.prefix); 2148 if (addr4 & ~mask) 2149 return -EINVAL; 2150 } else { 2151 struct in6_addr pfx; 2152 2153 if (ipv6_addr_any(addr6) || 2154 opt_in.prefix > 128) 2155 return -EINVAL; 2156 2157 ipv6_addr_prefix(&pfx, addr6, opt_in.prefix); 2158 if (ipv6_addr_cmp(&pfx, addr6)) 2159 return -EINVAL; 2160 } 2161 } else if (!ipv6_addr_any(addr6)) { 2162 return -EINVAL; 2163 } 2164 break; 2165 } 2166 case 0: 2167 if (!do_address_matching) 2168 break; 2169 fallthrough; 2170 default: 2171 return -EAFNOSUPPORT; 2172 } 2173 2174 if (!do_address_matching) { 2175 /* We could just ignore those, but let's do stricter checks */ 2176 if (addr || port) 2177 return -EINVAL; 2178 if (opt_in.prefix || opt_in.sndid || opt_in.rcvid) 2179 return -EINVAL; 2180 } 2181 2182 bytes_to_write = min_t(int, user_len, sizeof(struct tcp_ao_getsockopt)); 2183 matched_keys = 0; 2184 /* May change in RX, while we're dumping, pre-fetch it */ 2185 current_key = READ_ONCE(ao_info->current_key); 2186 2187 hlist_for_each_entry_rcu(key, &ao_info->head, node) { 2188 if (opt_in.get_all) 2189 goto match; 2190 2191 if (opt_in.is_current || opt_in.is_rnext) { 2192 if (opt_in.is_current && key == current_key) 2193 goto match; 2194 if (opt_in.is_rnext && key == ao_info->rnext_key) 2195 goto match; 2196 continue; 2197 } 2198 2199 if (tcp_ao_key_cmp(key, l3index, addr, opt_in.prefix, 2200 opt_in.addr.ss_family, 2201 opt_in.sndid, opt_in.rcvid) != 0) 2202 continue; 2203 match: 2204 matched_keys++; 2205 if (matched_keys > max_keys) 2206 continue; 2207 2208 memset(&opt_out, 0, sizeof(struct tcp_ao_getsockopt)); 2209 2210 if (key->family == AF_INET) { 2211 struct sockaddr_in *sin_out = (struct sockaddr_in *)&opt_out.addr; 2212 2213 sin_out->sin_family = key->family; 2214 sin_out->sin_port = 0; 2215 memcpy(&sin_out->sin_addr, &key->addr, sizeof(struct in_addr)); 2216 } else { 2217 struct sockaddr_in6 *sin6_out = (struct sockaddr_in6 *)&opt_out.addr; 2218 2219 sin6_out->sin6_family = key->family; 2220 sin6_out->sin6_port = 0; 2221 memcpy(&sin6_out->sin6_addr, &key->addr, sizeof(struct in6_addr)); 2222 } 2223 opt_out.sndid = key->sndid; 2224 opt_out.rcvid = key->rcvid; 2225 opt_out.prefix = key->prefixlen; 2226 opt_out.keyflags = key->keyflags; 2227 opt_out.is_current = (key == current_key); 2228 opt_out.is_rnext = (key == ao_info->rnext_key); 2229 opt_out.nkeys = 0; 2230 opt_out.maclen = key->maclen; 2231 opt_out.keylen = key->keylen; 2232 opt_out.ifindex = key->l3index; 2233 opt_out.pkt_good = atomic64_read(&key->pkt_good); 2234 opt_out.pkt_bad = atomic64_read(&key->pkt_bad); 2235 memcpy(&opt_out.key, key->key, key->keylen); 2236 tcp_sigpool_algo(key->tcp_sigpool_id, opt_out.alg_name, 64); 2237 2238 /* Copy key to user */ 2239 if (copy_to_sockptr_offset(optval, out_offset, 2240 &opt_out, bytes_to_write)) 2241 return -EFAULT; 2242 out_offset += user_len; 2243 } 2244 2245 optlen_out = (int)sizeof(struct tcp_ao_getsockopt); 2246 if (copy_to_sockptr(optlen, &optlen_out, sizeof(int))) 2247 return -EFAULT; 2248 2249 out_offset = offsetof(struct tcp_ao_getsockopt, nkeys); 2250 if (copy_to_sockptr_offset(optval, out_offset, 2251 &matched_keys, sizeof(u32))) 2252 return -EFAULT; 2253 2254 return 0; 2255 } 2256 2257 int tcp_ao_get_mkts(struct sock *sk, sockptr_t optval, sockptr_t optlen) 2258 { 2259 struct tcp_ao_info *ao_info; 2260 2261 ao_info = setsockopt_ao_info(sk); 2262 if (IS_ERR(ao_info)) 2263 return PTR_ERR(ao_info); 2264 if (!ao_info) 2265 return -ENOENT; 2266 2267 return tcp_ao_copy_mkts_to_user(ao_info, optval, optlen); 2268 } 2269 2270 int tcp_ao_get_sock_info(struct sock *sk, sockptr_t optval, sockptr_t optlen) 2271 { 2272 struct tcp_ao_info_opt out, in = {}; 2273 struct tcp_ao_key *current_key; 2274 struct tcp_ao_info *ao; 2275 int err, len; 2276 2277 if (copy_from_sockptr(&len, optlen, sizeof(int))) 2278 return -EFAULT; 2279 2280 if (len <= 0) 2281 return -EINVAL; 2282 2283 /* Copying this "in" only to check ::reserved, ::reserved2, 2284 * that may be needed to extend (struct tcp_ao_info_opt) and 2285 * what getsockopt() provides in future. 2286 */ 2287 err = copy_struct_from_sockptr(&in, sizeof(in), optval, len); 2288 if (err) 2289 return err; 2290 2291 if (in.reserved != 0 || in.reserved2 != 0) 2292 return -EINVAL; 2293 2294 ao = setsockopt_ao_info(sk); 2295 if (IS_ERR(ao)) 2296 return PTR_ERR(ao); 2297 if (!ao) 2298 return -ENOENT; 2299 2300 memset(&out, 0, sizeof(out)); 2301 out.ao_required = ao->ao_required; 2302 out.accept_icmps = ao->accept_icmps; 2303 out.pkt_good = atomic64_read(&ao->counters.pkt_good); 2304 out.pkt_bad = atomic64_read(&ao->counters.pkt_bad); 2305 out.pkt_key_not_found = atomic64_read(&ao->counters.key_not_found); 2306 out.pkt_ao_required = atomic64_read(&ao->counters.ao_required); 2307 out.pkt_dropped_icmp = atomic64_read(&ao->counters.dropped_icmp); 2308 2309 current_key = READ_ONCE(ao->current_key); 2310 if (current_key) { 2311 out.set_current = 1; 2312 out.current_key = current_key->sndid; 2313 } 2314 if (ao->rnext_key) { 2315 out.set_rnext = 1; 2316 out.rnext = ao->rnext_key->rcvid; 2317 } 2318 2319 if (copy_to_sockptr(optval, &out, min_t(int, len, sizeof(out)))) 2320 return -EFAULT; 2321 2322 return 0; 2323 } 2324 2325 int tcp_ao_set_repair(struct sock *sk, sockptr_t optval, unsigned int optlen) 2326 { 2327 struct tcp_sock *tp = tcp_sk(sk); 2328 struct tcp_ao_repair cmd; 2329 struct tcp_ao_key *key; 2330 struct tcp_ao_info *ao; 2331 int err; 2332 2333 if (optlen < sizeof(cmd)) 2334 return -EINVAL; 2335 2336 err = copy_struct_from_sockptr(&cmd, sizeof(cmd), optval, optlen); 2337 if (err) 2338 return err; 2339 2340 if (!tp->repair) 2341 return -EPERM; 2342 2343 ao = setsockopt_ao_info(sk); 2344 if (IS_ERR(ao)) 2345 return PTR_ERR(ao); 2346 if (!ao) 2347 return -ENOENT; 2348 2349 WRITE_ONCE(ao->lisn, cmd.snt_isn); 2350 WRITE_ONCE(ao->risn, cmd.rcv_isn); 2351 WRITE_ONCE(ao->snd_sne, cmd.snd_sne); 2352 WRITE_ONCE(ao->rcv_sne, cmd.rcv_sne); 2353 2354 hlist_for_each_entry_rcu(key, &ao->head, node) 2355 tcp_ao_cache_traffic_keys(sk, ao, key); 2356 2357 return 0; 2358 } 2359 2360 int tcp_ao_get_repair(struct sock *sk, sockptr_t optval, sockptr_t optlen) 2361 { 2362 struct tcp_sock *tp = tcp_sk(sk); 2363 struct tcp_ao_repair opt; 2364 struct tcp_ao_info *ao; 2365 int len; 2366 2367 if (copy_from_sockptr(&len, optlen, sizeof(int))) 2368 return -EFAULT; 2369 2370 if (len <= 0) 2371 return -EINVAL; 2372 2373 if (!tp->repair) 2374 return -EPERM; 2375 2376 rcu_read_lock(); 2377 ao = getsockopt_ao_info(sk); 2378 if (IS_ERR_OR_NULL(ao)) { 2379 rcu_read_unlock(); 2380 return ao ? PTR_ERR(ao) : -ENOENT; 2381 } 2382 2383 opt.snt_isn = ao->lisn; 2384 opt.rcv_isn = ao->risn; 2385 opt.snd_sne = READ_ONCE(ao->snd_sne); 2386 opt.rcv_sne = READ_ONCE(ao->rcv_sne); 2387 rcu_read_unlock(); 2388 2389 if (copy_to_sockptr(optval, &opt, min_t(int, len, sizeof(opt)))) 2390 return -EFAULT; 2391 return 0; 2392 } 2393