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 (including sackperm) 1319 * - wscale), 1320 * see tcp_syn_options(), tcp_synack_options(), commit 33ad798c924b. 1321 * 1322 * In order to allow D-SACK with TCP-AO, the header size should be: 1323 * (MAX_TCP_OPTION_SPACE - TCPOLEN_TSTAMP_ALIGNED 1324 * - TCPOLEN_SACK_BASE_ALIGNED 1325 * - 2 * TCPOLEN_SACK_PERBLOCK) = 8 (maclen = 4), 1326 * see tcp_established_options(). 1327 * 1328 * RFC5925, 2.2: 1329 * Typical MACs are 96-128 bits (12-16 bytes), but any length 1330 * that fits in the header of the segment being authenticated 1331 * is allowed. 1332 * 1333 * RFC5925, 7.6: 1334 * TCP-AO continues to consume 16 bytes in non-SYN segments, 1335 * leaving a total of 24 bytes for other options, of which 1336 * the timestamp consumes 10. This leaves 14 bytes, of which 10 1337 * are used for a single SACK block. When two SACK blocks are used, 1338 * such as to handle D-SACK, a smaller TCP-AO MAC would be required 1339 * to make room for the additional SACK block (i.e., to leave 18 1340 * bytes for the D-SACK variant of the SACK option) [RFC2883]. 1341 * Note that D-SACK is not supportable in TCP MD5 in the presence 1342 * of timestamps, because TCP MD5’s MAC length is fixed and too 1343 * large to leave sufficient option space. 1344 */ 1345 syn_tcp_option_space = MAX_TCP_OPTION_SPACE; 1346 syn_tcp_option_space -= TCPOLEN_MSS_ALIGNED; 1347 syn_tcp_option_space -= TCPOLEN_TSTAMP_ALIGNED; 1348 syn_tcp_option_space -= TCPOLEN_WSCALE_ALIGNED; 1349 if (tcp_ao_len(key) > syn_tcp_option_space) { 1350 err = -EMSGSIZE; 1351 goto err_kfree; 1352 } 1353 1354 key->keylen = cmd->keylen; 1355 memcpy(key->key, cmd->key, cmd->keylen); 1356 1357 err = tcp_sigpool_start(key->tcp_sigpool_id, &hp); 1358 if (err) 1359 goto err_kfree; 1360 1361 tfm = crypto_ahash_reqtfm(hp.req); 1362 if (is_kdf_aes_128_cmac) { 1363 void *scratch = hp.scratch; 1364 struct scatterlist sg; 1365 1366 memcpy(tmp_key, cmd->key, cmd->keylen); 1367 sg_init_one(&sg, tmp_key, cmd->keylen); 1368 1369 /* Using zero-key of 16 bytes as described in RFC5926 */ 1370 memset(scratch, 0, 16); 1371 err = crypto_ahash_setkey(tfm, scratch, 16); 1372 if (err) 1373 goto err_pool_end; 1374 1375 err = crypto_ahash_init(hp.req); 1376 if (err) 1377 goto err_pool_end; 1378 1379 ahash_request_set_crypt(hp.req, &sg, key->key, cmd->keylen); 1380 err = crypto_ahash_update(hp.req); 1381 if (err) 1382 goto err_pool_end; 1383 1384 err |= crypto_ahash_final(hp.req); 1385 if (err) 1386 goto err_pool_end; 1387 key->keylen = 16; 1388 } 1389 1390 err = crypto_ahash_setkey(tfm, key->key, key->keylen); 1391 if (err) 1392 goto err_pool_end; 1393 1394 tcp_sigpool_end(&hp); 1395 kfree_sensitive(tmp_key); 1396 1397 if (tcp_ao_maclen(key) > key->digest_size) 1398 return -EINVAL; 1399 1400 return 0; 1401 1402 err_pool_end: 1403 tcp_sigpool_end(&hp); 1404 err_kfree: 1405 kfree_sensitive(tmp_key); 1406 return err; 1407 } 1408 1409 #if IS_ENABLED(CONFIG_IPV6) 1410 static int tcp_ao_verify_ipv6(struct sock *sk, struct tcp_ao_add *cmd, 1411 union tcp_ao_addr **paddr, 1412 unsigned short int *family) 1413 { 1414 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd->addr; 1415 struct in6_addr *addr = &sin6->sin6_addr; 1416 u8 prefix = cmd->prefix; 1417 1418 if (sin6->sin6_family != AF_INET6) 1419 return -EINVAL; 1420 1421 /* Currently matching is not performed on port (or port ranges) */ 1422 if (sin6->sin6_port != 0) 1423 return -EINVAL; 1424 1425 /* Check prefix and trailing 0's in addr */ 1426 if (cmd->prefix != 0 && ipv6_addr_v4mapped(addr)) { 1427 __be32 addr4 = addr->s6_addr32[3]; 1428 __be32 mask; 1429 1430 if (prefix > 32 || ntohl(addr4) == INADDR_ANY) 1431 return -EINVAL; 1432 1433 mask = inet_make_mask(prefix); 1434 if (addr4 & ~mask) 1435 return -EINVAL; 1436 1437 /* Check that MKT address is consistent with socket */ 1438 if (!ipv6_addr_any(&sk->sk_v6_daddr)) { 1439 __be32 daddr4 = sk->sk_v6_daddr.s6_addr32[3]; 1440 1441 if (!ipv6_addr_v4mapped(&sk->sk_v6_daddr)) 1442 return -EINVAL; 1443 if ((daddr4 & mask) != addr4) 1444 return -EINVAL; 1445 } 1446 1447 *paddr = (union tcp_ao_addr *)&addr->s6_addr32[3]; 1448 *family = AF_INET; 1449 return 0; 1450 } else if (cmd->prefix != 0) { 1451 struct in6_addr pfx; 1452 1453 if (ipv6_addr_any(addr) || prefix > 128) 1454 return -EINVAL; 1455 1456 ipv6_addr_prefix(&pfx, addr, prefix); 1457 if (ipv6_addr_cmp(&pfx, addr)) 1458 return -EINVAL; 1459 1460 /* Check that MKT address is consistent with socket */ 1461 if (!ipv6_addr_any(&sk->sk_v6_daddr) && 1462 !ipv6_prefix_equal(&sk->sk_v6_daddr, addr, prefix)) 1463 1464 return -EINVAL; 1465 } else { 1466 if (!ipv6_addr_any(addr)) 1467 return -EINVAL; 1468 } 1469 1470 *paddr = (union tcp_ao_addr *)addr; 1471 return 0; 1472 } 1473 #else 1474 static int tcp_ao_verify_ipv6(struct sock *sk, struct tcp_ao_add *cmd, 1475 union tcp_ao_addr **paddr, 1476 unsigned short int *family) 1477 { 1478 return -EOPNOTSUPP; 1479 } 1480 #endif 1481 1482 static struct tcp_ao_info *setsockopt_ao_info(struct sock *sk) 1483 { 1484 if (sk_fullsock(sk)) { 1485 return rcu_dereference_protected(tcp_sk(sk)->ao_info, 1486 lockdep_sock_is_held(sk)); 1487 } else if (sk->sk_state == TCP_TIME_WAIT) { 1488 return rcu_dereference_protected(tcp_twsk(sk)->ao_info, 1489 lockdep_sock_is_held(sk)); 1490 } 1491 return ERR_PTR(-ESOCKTNOSUPPORT); 1492 } 1493 1494 static struct tcp_ao_info *getsockopt_ao_info(struct sock *sk) 1495 { 1496 if (sk_fullsock(sk)) 1497 return rcu_dereference(tcp_sk(sk)->ao_info); 1498 else if (sk->sk_state == TCP_TIME_WAIT) 1499 return rcu_dereference(tcp_twsk(sk)->ao_info); 1500 1501 return ERR_PTR(-ESOCKTNOSUPPORT); 1502 } 1503 1504 #define TCP_AO_KEYF_ALL (TCP_AO_KEYF_IFINDEX | TCP_AO_KEYF_EXCLUDE_OPT) 1505 #define TCP_AO_GET_KEYF_VALID (TCP_AO_KEYF_IFINDEX) 1506 1507 static struct tcp_ao_key *tcp_ao_key_alloc(struct sock *sk, 1508 struct tcp_ao_add *cmd) 1509 { 1510 const char *algo = cmd->alg_name; 1511 unsigned int digest_size; 1512 struct crypto_ahash *tfm; 1513 struct tcp_ao_key *key; 1514 struct tcp_sigpool hp; 1515 int err, pool_id; 1516 size_t size; 1517 1518 /* Force null-termination of alg_name */ 1519 cmd->alg_name[ARRAY_SIZE(cmd->alg_name) - 1] = '\0'; 1520 1521 /* RFC5926, 3.1.1.2. KDF_AES_128_CMAC */ 1522 if (!strcmp("cmac(aes128)", algo)) 1523 algo = "cmac(aes)"; 1524 1525 /* Full TCP header (th->doff << 2) should fit into scratch area, 1526 * see tcp_ao_hash_header(). 1527 */ 1528 pool_id = tcp_sigpool_alloc_ahash(algo, 60); 1529 if (pool_id < 0) 1530 return ERR_PTR(pool_id); 1531 1532 err = tcp_sigpool_start(pool_id, &hp); 1533 if (err) 1534 goto err_free_pool; 1535 1536 tfm = crypto_ahash_reqtfm(hp.req); 1537 digest_size = crypto_ahash_digestsize(tfm); 1538 tcp_sigpool_end(&hp); 1539 1540 size = sizeof(struct tcp_ao_key) + (digest_size << 1); 1541 key = sock_kmalloc(sk, size, GFP_KERNEL); 1542 if (!key) { 1543 err = -ENOMEM; 1544 goto err_free_pool; 1545 } 1546 1547 key->tcp_sigpool_id = pool_id; 1548 key->digest_size = digest_size; 1549 return key; 1550 1551 err_free_pool: 1552 tcp_sigpool_release(pool_id); 1553 return ERR_PTR(err); 1554 } 1555 1556 static int tcp_ao_add_cmd(struct sock *sk, unsigned short int family, 1557 sockptr_t optval, int optlen) 1558 { 1559 struct tcp_ao_info *ao_info; 1560 union tcp_ao_addr *addr; 1561 struct tcp_ao_key *key; 1562 struct tcp_ao_add cmd; 1563 int ret, l3index = 0; 1564 bool first = false; 1565 1566 if (optlen < sizeof(cmd)) 1567 return -EINVAL; 1568 1569 ret = copy_struct_from_sockptr(&cmd, sizeof(cmd), optval, optlen); 1570 if (ret) 1571 return ret; 1572 1573 if (cmd.keylen > TCP_AO_MAXKEYLEN) 1574 return -EINVAL; 1575 1576 if (cmd.reserved != 0 || cmd.reserved2 != 0) 1577 return -EINVAL; 1578 1579 if (family == AF_INET) 1580 ret = tcp_ao_verify_ipv4(sk, &cmd, &addr); 1581 else 1582 ret = tcp_ao_verify_ipv6(sk, &cmd, &addr, &family); 1583 if (ret) 1584 return ret; 1585 1586 if (cmd.keyflags & ~TCP_AO_KEYF_ALL) 1587 return -EINVAL; 1588 1589 if (cmd.set_current || cmd.set_rnext) { 1590 if (!tcp_ao_can_set_current_rnext(sk)) 1591 return -EINVAL; 1592 } 1593 1594 if (cmd.ifindex && !(cmd.keyflags & TCP_AO_KEYF_IFINDEX)) 1595 return -EINVAL; 1596 1597 /* For cmd.tcp_ifindex = 0 the key will apply to the default VRF */ 1598 if (cmd.keyflags & TCP_AO_KEYF_IFINDEX && cmd.ifindex) { 1599 int bound_dev_if = READ_ONCE(sk->sk_bound_dev_if); 1600 struct net_device *dev; 1601 1602 rcu_read_lock(); 1603 dev = dev_get_by_index_rcu(sock_net(sk), cmd.ifindex); 1604 if (dev && netif_is_l3_master(dev)) 1605 l3index = dev->ifindex; 1606 rcu_read_unlock(); 1607 1608 if (!dev || !l3index) 1609 return -EINVAL; 1610 1611 /* It's still possible to bind after adding keys or even 1612 * re-bind to a different dev (with CAP_NET_RAW). 1613 * So, no reason to return error here, rather try to be 1614 * nice and warn the user. 1615 */ 1616 if (bound_dev_if && bound_dev_if != cmd.ifindex) 1617 net_warn_ratelimited("AO key ifindex %d != sk bound ifindex %d\n", 1618 cmd.ifindex, bound_dev_if); 1619 } 1620 1621 /* Don't allow keys for peers that have a matching TCP-MD5 key */ 1622 if (cmd.keyflags & TCP_AO_KEYF_IFINDEX) { 1623 /* Non-_exact version of tcp_md5_do_lookup() will 1624 * as well match keys that aren't bound to a specific VRF 1625 * (that will make them match AO key with 1626 * sysctl_tcp_l3dev_accept = 1 1627 */ 1628 if (tcp_md5_do_lookup(sk, l3index, addr, family)) 1629 return -EKEYREJECTED; 1630 } else { 1631 if (tcp_md5_do_lookup_any_l3index(sk, addr, family)) 1632 return -EKEYREJECTED; 1633 } 1634 1635 ao_info = setsockopt_ao_info(sk); 1636 if (IS_ERR(ao_info)) 1637 return PTR_ERR(ao_info); 1638 1639 if (!ao_info) { 1640 ao_info = tcp_ao_alloc_info(GFP_KERNEL); 1641 if (!ao_info) 1642 return -ENOMEM; 1643 first = true; 1644 } else { 1645 /* Check that neither RecvID nor SendID match any 1646 * existing key for the peer, RFC5925 3.1: 1647 * > The IDs of MKTs MUST NOT overlap where their 1648 * > TCP connection identifiers overlap. 1649 */ 1650 if (__tcp_ao_do_lookup(sk, l3index, addr, family, cmd.prefix, -1, cmd.rcvid)) 1651 return -EEXIST; 1652 if (__tcp_ao_do_lookup(sk, l3index, addr, family, 1653 cmd.prefix, cmd.sndid, -1)) 1654 return -EEXIST; 1655 } 1656 1657 key = tcp_ao_key_alloc(sk, &cmd); 1658 if (IS_ERR(key)) { 1659 ret = PTR_ERR(key); 1660 goto err_free_ao; 1661 } 1662 1663 INIT_HLIST_NODE(&key->node); 1664 memcpy(&key->addr, addr, (family == AF_INET) ? sizeof(struct in_addr) : 1665 sizeof(struct in6_addr)); 1666 key->prefixlen = cmd.prefix; 1667 key->family = family; 1668 key->keyflags = cmd.keyflags; 1669 key->sndid = cmd.sndid; 1670 key->rcvid = cmd.rcvid; 1671 key->l3index = l3index; 1672 atomic64_set(&key->pkt_good, 0); 1673 atomic64_set(&key->pkt_bad, 0); 1674 1675 ret = tcp_ao_parse_crypto(&cmd, key); 1676 if (ret < 0) 1677 goto err_free_sock; 1678 1679 if (!((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))) { 1680 tcp_ao_cache_traffic_keys(sk, ao_info, key); 1681 if (first) { 1682 ao_info->current_key = key; 1683 ao_info->rnext_key = key; 1684 } 1685 } 1686 1687 tcp_ao_link_mkt(ao_info, key); 1688 if (first) { 1689 if (!static_branch_inc(&tcp_ao_needed.key)) { 1690 ret = -EUSERS; 1691 goto err_free_sock; 1692 } 1693 sk_gso_disable(sk); 1694 rcu_assign_pointer(tcp_sk(sk)->ao_info, ao_info); 1695 } 1696 1697 if (cmd.set_current) 1698 WRITE_ONCE(ao_info->current_key, key); 1699 if (cmd.set_rnext) 1700 WRITE_ONCE(ao_info->rnext_key, key); 1701 return 0; 1702 1703 err_free_sock: 1704 atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc); 1705 tcp_sigpool_release(key->tcp_sigpool_id); 1706 kfree_sensitive(key); 1707 err_free_ao: 1708 if (first) 1709 kfree(ao_info); 1710 return ret; 1711 } 1712 1713 static int tcp_ao_delete_key(struct sock *sk, struct tcp_ao_info *ao_info, 1714 bool del_async, struct tcp_ao_key *key, 1715 struct tcp_ao_key *new_current, 1716 struct tcp_ao_key *new_rnext) 1717 { 1718 int err; 1719 1720 hlist_del_rcu(&key->node); 1721 1722 /* Support for async delete on listening sockets: as they don't 1723 * need current_key/rnext_key maintaining, we don't need to check 1724 * them and we can just free all resources in RCU fashion. 1725 */ 1726 if (del_async) { 1727 atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc); 1728 call_rcu(&key->rcu, tcp_ao_key_free_rcu); 1729 return 0; 1730 } 1731 1732 /* At this moment another CPU could have looked this key up 1733 * while it was unlinked from the list. Wait for RCU grace period, 1734 * after which the key is off-list and can't be looked up again; 1735 * the rx path [just before RCU came] might have used it and set it 1736 * as current_key (very unlikely). 1737 * Free the key with next RCU grace period (in case it was 1738 * current_key before tcp_ao_current_rnext() might have 1739 * changed it in forced-delete). 1740 */ 1741 synchronize_rcu(); 1742 if (new_current) 1743 WRITE_ONCE(ao_info->current_key, new_current); 1744 if (new_rnext) 1745 WRITE_ONCE(ao_info->rnext_key, new_rnext); 1746 1747 if (unlikely(READ_ONCE(ao_info->current_key) == key || 1748 READ_ONCE(ao_info->rnext_key) == key)) { 1749 err = -EBUSY; 1750 goto add_key; 1751 } 1752 1753 atomic_sub(tcp_ao_sizeof_key(key), &sk->sk_omem_alloc); 1754 call_rcu(&key->rcu, tcp_ao_key_free_rcu); 1755 1756 return 0; 1757 add_key: 1758 hlist_add_head_rcu(&key->node, &ao_info->head); 1759 return err; 1760 } 1761 1762 #define TCP_AO_DEL_KEYF_ALL (TCP_AO_KEYF_IFINDEX) 1763 static int tcp_ao_del_cmd(struct sock *sk, unsigned short int family, 1764 sockptr_t optval, int optlen) 1765 { 1766 struct tcp_ao_key *key, *new_current = NULL, *new_rnext = NULL; 1767 int err, addr_len, l3index = 0; 1768 struct tcp_ao_info *ao_info; 1769 union tcp_ao_addr *addr; 1770 struct tcp_ao_del cmd; 1771 __u8 prefix; 1772 u16 port; 1773 1774 if (optlen < sizeof(cmd)) 1775 return -EINVAL; 1776 1777 err = copy_struct_from_sockptr(&cmd, sizeof(cmd), optval, optlen); 1778 if (err) 1779 return err; 1780 1781 if (cmd.reserved != 0 || cmd.reserved2 != 0) 1782 return -EINVAL; 1783 1784 if (cmd.set_current || cmd.set_rnext) { 1785 if (!tcp_ao_can_set_current_rnext(sk)) 1786 return -EINVAL; 1787 } 1788 1789 if (cmd.keyflags & ~TCP_AO_DEL_KEYF_ALL) 1790 return -EINVAL; 1791 1792 /* No sanity check for TCP_AO_KEYF_IFINDEX as if a VRF 1793 * was destroyed, there still should be a way to delete keys, 1794 * that were bound to that l3intf. So, fail late at lookup stage 1795 * if there is no key for that ifindex. 1796 */ 1797 if (cmd.ifindex && !(cmd.keyflags & TCP_AO_KEYF_IFINDEX)) 1798 return -EINVAL; 1799 1800 ao_info = setsockopt_ao_info(sk); 1801 if (IS_ERR(ao_info)) 1802 return PTR_ERR(ao_info); 1803 if (!ao_info) 1804 return -ENOENT; 1805 1806 /* For sockets in TCP_CLOSED it's possible set keys that aren't 1807 * matching the future peer (address/VRF/etc), 1808 * tcp_ao_connect_init() will choose a correct matching MKT 1809 * if there's any. 1810 */ 1811 if (cmd.set_current) { 1812 new_current = tcp_ao_established_key(ao_info, cmd.current_key, -1); 1813 if (!new_current) 1814 return -ENOENT; 1815 } 1816 if (cmd.set_rnext) { 1817 new_rnext = tcp_ao_established_key(ao_info, -1, cmd.rnext); 1818 if (!new_rnext) 1819 return -ENOENT; 1820 } 1821 if (cmd.del_async && sk->sk_state != TCP_LISTEN) 1822 return -EINVAL; 1823 1824 if (family == AF_INET) { 1825 struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.addr; 1826 1827 addr = (union tcp_ao_addr *)&sin->sin_addr; 1828 addr_len = sizeof(struct in_addr); 1829 port = ntohs(sin->sin_port); 1830 } else { 1831 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.addr; 1832 struct in6_addr *addr6 = &sin6->sin6_addr; 1833 1834 if (ipv6_addr_v4mapped(addr6)) { 1835 addr = (union tcp_ao_addr *)&addr6->s6_addr32[3]; 1836 addr_len = sizeof(struct in_addr); 1837 family = AF_INET; 1838 } else { 1839 addr = (union tcp_ao_addr *)addr6; 1840 addr_len = sizeof(struct in6_addr); 1841 } 1842 port = ntohs(sin6->sin6_port); 1843 } 1844 prefix = cmd.prefix; 1845 1846 /* Currently matching is not performed on port (or port ranges) */ 1847 if (port != 0) 1848 return -EINVAL; 1849 1850 /* We could choose random present key here for current/rnext 1851 * but that's less predictable. Let's be strict and don't 1852 * allow removing a key that's in use. RFC5925 doesn't 1853 * specify how-to coordinate key removal, but says: 1854 * "It is presumed that an MKT affecting a particular 1855 * connection cannot be destroyed during an active connection" 1856 */ 1857 hlist_for_each_entry_rcu(key, &ao_info->head, node) { 1858 if (cmd.sndid != key->sndid || 1859 cmd.rcvid != key->rcvid) 1860 continue; 1861 1862 if (family != key->family || 1863 prefix != key->prefixlen || 1864 memcmp(addr, &key->addr, addr_len)) 1865 continue; 1866 1867 if ((cmd.keyflags & TCP_AO_KEYF_IFINDEX) != 1868 (key->keyflags & TCP_AO_KEYF_IFINDEX)) 1869 continue; 1870 1871 if (key->l3index != l3index) 1872 continue; 1873 1874 if (key == new_current || key == new_rnext) 1875 continue; 1876 1877 return tcp_ao_delete_key(sk, ao_info, cmd.del_async, key, 1878 new_current, new_rnext); 1879 } 1880 return -ENOENT; 1881 } 1882 1883 /* cmd.ao_required makes a socket TCP-AO only. 1884 * Don't allow any md5 keys for any l3intf on the socket together with it. 1885 * Restricting it early in setsockopt() removes a check for 1886 * ao_info->ao_required on inbound tcp segment fast-path. 1887 */ 1888 static int tcp_ao_required_verify(struct sock *sk) 1889 { 1890 #ifdef CONFIG_TCP_MD5SIG 1891 const struct tcp_md5sig_info *md5sig; 1892 1893 if (!static_branch_unlikely(&tcp_md5_needed.key)) 1894 return 0; 1895 1896 md5sig = rcu_dereference_check(tcp_sk(sk)->md5sig_info, 1897 lockdep_sock_is_held(sk)); 1898 if (!md5sig) 1899 return 0; 1900 1901 if (rcu_dereference_check(hlist_first_rcu(&md5sig->head), 1902 lockdep_sock_is_held(sk))) 1903 return 1; 1904 #endif 1905 return 0; 1906 } 1907 1908 static int tcp_ao_info_cmd(struct sock *sk, unsigned short int family, 1909 sockptr_t optval, int optlen) 1910 { 1911 struct tcp_ao_key *new_current = NULL, *new_rnext = NULL; 1912 struct tcp_ao_info *ao_info; 1913 struct tcp_ao_info_opt cmd; 1914 bool first = false; 1915 int err; 1916 1917 if (optlen < sizeof(cmd)) 1918 return -EINVAL; 1919 1920 err = copy_struct_from_sockptr(&cmd, sizeof(cmd), optval, optlen); 1921 if (err) 1922 return err; 1923 1924 if (cmd.set_current || cmd.set_rnext) { 1925 if (!tcp_ao_can_set_current_rnext(sk)) 1926 return -EINVAL; 1927 } 1928 1929 if (cmd.reserved != 0 || cmd.reserved2 != 0) 1930 return -EINVAL; 1931 1932 ao_info = setsockopt_ao_info(sk); 1933 if (IS_ERR(ao_info)) 1934 return PTR_ERR(ao_info); 1935 if (!ao_info) { 1936 if (!((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))) 1937 return -EINVAL; 1938 ao_info = tcp_ao_alloc_info(GFP_KERNEL); 1939 if (!ao_info) 1940 return -ENOMEM; 1941 first = true; 1942 } 1943 1944 if (cmd.ao_required && tcp_ao_required_verify(sk)) 1945 return -EKEYREJECTED; 1946 1947 /* For sockets in TCP_CLOSED it's possible set keys that aren't 1948 * matching the future peer (address/port/VRF/etc), 1949 * tcp_ao_connect_init() will choose a correct matching MKT 1950 * if there's any. 1951 */ 1952 if (cmd.set_current) { 1953 new_current = tcp_ao_established_key(ao_info, cmd.current_key, -1); 1954 if (!new_current) { 1955 err = -ENOENT; 1956 goto out; 1957 } 1958 } 1959 if (cmd.set_rnext) { 1960 new_rnext = tcp_ao_established_key(ao_info, -1, cmd.rnext); 1961 if (!new_rnext) { 1962 err = -ENOENT; 1963 goto out; 1964 } 1965 } 1966 if (cmd.set_counters) { 1967 atomic64_set(&ao_info->counters.pkt_good, cmd.pkt_good); 1968 atomic64_set(&ao_info->counters.pkt_bad, cmd.pkt_bad); 1969 atomic64_set(&ao_info->counters.key_not_found, cmd.pkt_key_not_found); 1970 atomic64_set(&ao_info->counters.ao_required, cmd.pkt_ao_required); 1971 atomic64_set(&ao_info->counters.dropped_icmp, cmd.pkt_dropped_icmp); 1972 } 1973 1974 ao_info->ao_required = cmd.ao_required; 1975 ao_info->accept_icmps = cmd.accept_icmps; 1976 if (new_current) 1977 WRITE_ONCE(ao_info->current_key, new_current); 1978 if (new_rnext) 1979 WRITE_ONCE(ao_info->rnext_key, new_rnext); 1980 if (first) { 1981 if (!static_branch_inc(&tcp_ao_needed.key)) { 1982 err = -EUSERS; 1983 goto out; 1984 } 1985 sk_gso_disable(sk); 1986 rcu_assign_pointer(tcp_sk(sk)->ao_info, ao_info); 1987 } 1988 return 0; 1989 out: 1990 if (first) 1991 kfree(ao_info); 1992 return err; 1993 } 1994 1995 int tcp_parse_ao(struct sock *sk, int cmd, unsigned short int family, 1996 sockptr_t optval, int optlen) 1997 { 1998 if (WARN_ON_ONCE(family != AF_INET && family != AF_INET6)) 1999 return -EAFNOSUPPORT; 2000 2001 switch (cmd) { 2002 case TCP_AO_ADD_KEY: 2003 return tcp_ao_add_cmd(sk, family, optval, optlen); 2004 case TCP_AO_DEL_KEY: 2005 return tcp_ao_del_cmd(sk, family, optval, optlen); 2006 case TCP_AO_INFO: 2007 return tcp_ao_info_cmd(sk, family, optval, optlen); 2008 default: 2009 WARN_ON_ONCE(1); 2010 return -EINVAL; 2011 } 2012 } 2013 2014 int tcp_v4_parse_ao(struct sock *sk, int cmd, sockptr_t optval, int optlen) 2015 { 2016 return tcp_parse_ao(sk, cmd, AF_INET, optval, optlen); 2017 } 2018 2019 /* tcp_ao_copy_mkts_to_user(ao_info, optval, optlen) 2020 * 2021 * @ao_info: struct tcp_ao_info on the socket that 2022 * socket getsockopt(TCP_AO_GET_KEYS) is executed on 2023 * @optval: pointer to array of tcp_ao_getsockopt structures in user space. 2024 * Must be != NULL. 2025 * @optlen: pointer to size of tcp_ao_getsockopt structure. 2026 * Must be != NULL. 2027 * 2028 * Return value: 0 on success, a negative error number otherwise. 2029 * 2030 * optval points to an array of tcp_ao_getsockopt structures in user space. 2031 * optval[0] is used as both input and output to getsockopt. It determines 2032 * which keys are returned by the kernel. 2033 * optval[0].nkeys is the size of the array in user space. On return it contains 2034 * the number of keys matching the search criteria. 2035 * If tcp_ao_getsockopt::get_all is set, then all keys in the socket are 2036 * returned, otherwise only keys matching <addr, prefix, sndid, rcvid> 2037 * in optval[0] are returned. 2038 * optlen is also used as both input and output. The user provides the size 2039 * of struct tcp_ao_getsockopt in user space, and the kernel returns the size 2040 * of the structure in kernel space. 2041 * The size of struct tcp_ao_getsockopt may differ between user and kernel. 2042 * There are three cases to consider: 2043 * * If usize == ksize, then keys are copied verbatim. 2044 * * If usize < ksize, then the userspace has passed an old struct to a 2045 * newer kernel. The rest of the trailing bytes in optval[0] 2046 * (ksize - usize) are interpreted as 0 by the kernel. 2047 * * If usize > ksize, then the userspace has passed a new struct to an 2048 * older kernel. The trailing bytes unknown to the kernel (usize - ksize) 2049 * are checked to ensure they are zeroed, otherwise -E2BIG is returned. 2050 * On return the kernel fills in min(usize, ksize) in each entry of the array. 2051 * The layout of the fields in the user and kernel structures is expected to 2052 * be the same (including in the 32bit vs 64bit case). 2053 */ 2054 static int tcp_ao_copy_mkts_to_user(struct tcp_ao_info *ao_info, 2055 sockptr_t optval, sockptr_t optlen) 2056 { 2057 struct tcp_ao_getsockopt opt_in, opt_out; 2058 struct tcp_ao_key *key, *current_key; 2059 bool do_address_matching = true; 2060 union tcp_ao_addr *addr = NULL; 2061 int err, l3index, user_len; 2062 unsigned int max_keys; /* maximum number of keys to copy to user */ 2063 size_t out_offset = 0; 2064 size_t bytes_to_write; /* number of bytes to write to user level */ 2065 u32 matched_keys; /* keys from ao_info matched so far */ 2066 int optlen_out; 2067 __be16 port = 0; 2068 2069 if (copy_from_sockptr(&user_len, optlen, sizeof(int))) 2070 return -EFAULT; 2071 2072 if (user_len <= 0) 2073 return -EINVAL; 2074 2075 memset(&opt_in, 0, sizeof(struct tcp_ao_getsockopt)); 2076 err = copy_struct_from_sockptr(&opt_in, sizeof(opt_in), 2077 optval, user_len); 2078 if (err < 0) 2079 return err; 2080 2081 if (opt_in.pkt_good || opt_in.pkt_bad) 2082 return -EINVAL; 2083 if (opt_in.keyflags & ~TCP_AO_GET_KEYF_VALID) 2084 return -EINVAL; 2085 if (opt_in.ifindex && !(opt_in.keyflags & TCP_AO_KEYF_IFINDEX)) 2086 return -EINVAL; 2087 2088 if (opt_in.reserved != 0) 2089 return -EINVAL; 2090 2091 max_keys = opt_in.nkeys; 2092 l3index = (opt_in.keyflags & TCP_AO_KEYF_IFINDEX) ? opt_in.ifindex : -1; 2093 2094 if (opt_in.get_all || opt_in.is_current || opt_in.is_rnext) { 2095 if (opt_in.get_all && (opt_in.is_current || opt_in.is_rnext)) 2096 return -EINVAL; 2097 do_address_matching = false; 2098 } 2099 2100 switch (opt_in.addr.ss_family) { 2101 case AF_INET: { 2102 struct sockaddr_in *sin; 2103 __be32 mask; 2104 2105 sin = (struct sockaddr_in *)&opt_in.addr; 2106 port = sin->sin_port; 2107 addr = (union tcp_ao_addr *)&sin->sin_addr; 2108 2109 if (opt_in.prefix > 32) 2110 return -EINVAL; 2111 2112 if (ntohl(sin->sin_addr.s_addr) == INADDR_ANY && 2113 opt_in.prefix != 0) 2114 return -EINVAL; 2115 2116 mask = inet_make_mask(opt_in.prefix); 2117 if (sin->sin_addr.s_addr & ~mask) 2118 return -EINVAL; 2119 2120 break; 2121 } 2122 case AF_INET6: { 2123 struct sockaddr_in6 *sin6; 2124 struct in6_addr *addr6; 2125 2126 sin6 = (struct sockaddr_in6 *)&opt_in.addr; 2127 addr = (union tcp_ao_addr *)&sin6->sin6_addr; 2128 addr6 = &sin6->sin6_addr; 2129 port = sin6->sin6_port; 2130 2131 /* We don't have to change family and @addr here if 2132 * ipv6_addr_v4mapped() like in key adding: 2133 * tcp_ao_key_cmp() does it. Do the sanity checks though. 2134 */ 2135 if (opt_in.prefix != 0) { 2136 if (ipv6_addr_v4mapped(addr6)) { 2137 __be32 mask, addr4 = addr6->s6_addr32[3]; 2138 2139 if (opt_in.prefix > 32 || 2140 ntohl(addr4) == INADDR_ANY) 2141 return -EINVAL; 2142 mask = inet_make_mask(opt_in.prefix); 2143 if (addr4 & ~mask) 2144 return -EINVAL; 2145 } else { 2146 struct in6_addr pfx; 2147 2148 if (ipv6_addr_any(addr6) || 2149 opt_in.prefix > 128) 2150 return -EINVAL; 2151 2152 ipv6_addr_prefix(&pfx, addr6, opt_in.prefix); 2153 if (ipv6_addr_cmp(&pfx, addr6)) 2154 return -EINVAL; 2155 } 2156 } else if (!ipv6_addr_any(addr6)) { 2157 return -EINVAL; 2158 } 2159 break; 2160 } 2161 case 0: 2162 if (!do_address_matching) 2163 break; 2164 fallthrough; 2165 default: 2166 return -EAFNOSUPPORT; 2167 } 2168 2169 if (!do_address_matching) { 2170 /* We could just ignore those, but let's do stricter checks */ 2171 if (addr || port) 2172 return -EINVAL; 2173 if (opt_in.prefix || opt_in.sndid || opt_in.rcvid) 2174 return -EINVAL; 2175 } 2176 2177 bytes_to_write = min_t(int, user_len, sizeof(struct tcp_ao_getsockopt)); 2178 matched_keys = 0; 2179 /* May change in RX, while we're dumping, pre-fetch it */ 2180 current_key = READ_ONCE(ao_info->current_key); 2181 2182 hlist_for_each_entry_rcu(key, &ao_info->head, node) { 2183 if (opt_in.get_all) 2184 goto match; 2185 2186 if (opt_in.is_current || opt_in.is_rnext) { 2187 if (opt_in.is_current && key == current_key) 2188 goto match; 2189 if (opt_in.is_rnext && key == ao_info->rnext_key) 2190 goto match; 2191 continue; 2192 } 2193 2194 if (tcp_ao_key_cmp(key, l3index, addr, opt_in.prefix, 2195 opt_in.addr.ss_family, 2196 opt_in.sndid, opt_in.rcvid) != 0) 2197 continue; 2198 match: 2199 matched_keys++; 2200 if (matched_keys > max_keys) 2201 continue; 2202 2203 memset(&opt_out, 0, sizeof(struct tcp_ao_getsockopt)); 2204 2205 if (key->family == AF_INET) { 2206 struct sockaddr_in *sin_out = (struct sockaddr_in *)&opt_out.addr; 2207 2208 sin_out->sin_family = key->family; 2209 sin_out->sin_port = 0; 2210 memcpy(&sin_out->sin_addr, &key->addr, sizeof(struct in_addr)); 2211 } else { 2212 struct sockaddr_in6 *sin6_out = (struct sockaddr_in6 *)&opt_out.addr; 2213 2214 sin6_out->sin6_family = key->family; 2215 sin6_out->sin6_port = 0; 2216 memcpy(&sin6_out->sin6_addr, &key->addr, sizeof(struct in6_addr)); 2217 } 2218 opt_out.sndid = key->sndid; 2219 opt_out.rcvid = key->rcvid; 2220 opt_out.prefix = key->prefixlen; 2221 opt_out.keyflags = key->keyflags; 2222 opt_out.is_current = (key == current_key); 2223 opt_out.is_rnext = (key == ao_info->rnext_key); 2224 opt_out.nkeys = 0; 2225 opt_out.maclen = key->maclen; 2226 opt_out.keylen = key->keylen; 2227 opt_out.ifindex = key->l3index; 2228 opt_out.pkt_good = atomic64_read(&key->pkt_good); 2229 opt_out.pkt_bad = atomic64_read(&key->pkt_bad); 2230 memcpy(&opt_out.key, key->key, key->keylen); 2231 tcp_sigpool_algo(key->tcp_sigpool_id, opt_out.alg_name, 64); 2232 2233 /* Copy key to user */ 2234 if (copy_to_sockptr_offset(optval, out_offset, 2235 &opt_out, bytes_to_write)) 2236 return -EFAULT; 2237 out_offset += user_len; 2238 } 2239 2240 optlen_out = (int)sizeof(struct tcp_ao_getsockopt); 2241 if (copy_to_sockptr(optlen, &optlen_out, sizeof(int))) 2242 return -EFAULT; 2243 2244 out_offset = offsetof(struct tcp_ao_getsockopt, nkeys); 2245 if (copy_to_sockptr_offset(optval, out_offset, 2246 &matched_keys, sizeof(u32))) 2247 return -EFAULT; 2248 2249 return 0; 2250 } 2251 2252 int tcp_ao_get_mkts(struct sock *sk, sockptr_t optval, sockptr_t optlen) 2253 { 2254 struct tcp_ao_info *ao_info; 2255 2256 ao_info = setsockopt_ao_info(sk); 2257 if (IS_ERR(ao_info)) 2258 return PTR_ERR(ao_info); 2259 if (!ao_info) 2260 return -ENOENT; 2261 2262 return tcp_ao_copy_mkts_to_user(ao_info, optval, optlen); 2263 } 2264 2265 int tcp_ao_get_sock_info(struct sock *sk, sockptr_t optval, sockptr_t optlen) 2266 { 2267 struct tcp_ao_info_opt out, in = {}; 2268 struct tcp_ao_key *current_key; 2269 struct tcp_ao_info *ao; 2270 int err, len; 2271 2272 if (copy_from_sockptr(&len, optlen, sizeof(int))) 2273 return -EFAULT; 2274 2275 if (len <= 0) 2276 return -EINVAL; 2277 2278 /* Copying this "in" only to check ::reserved, ::reserved2, 2279 * that may be needed to extend (struct tcp_ao_info_opt) and 2280 * what getsockopt() provides in future. 2281 */ 2282 err = copy_struct_from_sockptr(&in, sizeof(in), optval, len); 2283 if (err) 2284 return err; 2285 2286 if (in.reserved != 0 || in.reserved2 != 0) 2287 return -EINVAL; 2288 2289 ao = setsockopt_ao_info(sk); 2290 if (IS_ERR(ao)) 2291 return PTR_ERR(ao); 2292 if (!ao) 2293 return -ENOENT; 2294 2295 memset(&out, 0, sizeof(out)); 2296 out.ao_required = ao->ao_required; 2297 out.accept_icmps = ao->accept_icmps; 2298 out.pkt_good = atomic64_read(&ao->counters.pkt_good); 2299 out.pkt_bad = atomic64_read(&ao->counters.pkt_bad); 2300 out.pkt_key_not_found = atomic64_read(&ao->counters.key_not_found); 2301 out.pkt_ao_required = atomic64_read(&ao->counters.ao_required); 2302 out.pkt_dropped_icmp = atomic64_read(&ao->counters.dropped_icmp); 2303 2304 current_key = READ_ONCE(ao->current_key); 2305 if (current_key) { 2306 out.set_current = 1; 2307 out.current_key = current_key->sndid; 2308 } 2309 if (ao->rnext_key) { 2310 out.set_rnext = 1; 2311 out.rnext = ao->rnext_key->rcvid; 2312 } 2313 2314 if (copy_to_sockptr(optval, &out, min_t(int, len, sizeof(out)))) 2315 return -EFAULT; 2316 2317 return 0; 2318 } 2319 2320 int tcp_ao_set_repair(struct sock *sk, sockptr_t optval, unsigned int optlen) 2321 { 2322 struct tcp_sock *tp = tcp_sk(sk); 2323 struct tcp_ao_repair cmd; 2324 struct tcp_ao_key *key; 2325 struct tcp_ao_info *ao; 2326 int err; 2327 2328 if (optlen < sizeof(cmd)) 2329 return -EINVAL; 2330 2331 err = copy_struct_from_sockptr(&cmd, sizeof(cmd), optval, optlen); 2332 if (err) 2333 return err; 2334 2335 if (!tp->repair) 2336 return -EPERM; 2337 2338 ao = setsockopt_ao_info(sk); 2339 if (IS_ERR(ao)) 2340 return PTR_ERR(ao); 2341 if (!ao) 2342 return -ENOENT; 2343 2344 WRITE_ONCE(ao->lisn, cmd.snt_isn); 2345 WRITE_ONCE(ao->risn, cmd.rcv_isn); 2346 WRITE_ONCE(ao->snd_sne, cmd.snd_sne); 2347 WRITE_ONCE(ao->rcv_sne, cmd.rcv_sne); 2348 2349 hlist_for_each_entry_rcu(key, &ao->head, node) 2350 tcp_ao_cache_traffic_keys(sk, ao, key); 2351 2352 return 0; 2353 } 2354 2355 int tcp_ao_get_repair(struct sock *sk, sockptr_t optval, sockptr_t optlen) 2356 { 2357 struct tcp_sock *tp = tcp_sk(sk); 2358 struct tcp_ao_repair opt; 2359 struct tcp_ao_info *ao; 2360 int len; 2361 2362 if (copy_from_sockptr(&len, optlen, sizeof(int))) 2363 return -EFAULT; 2364 2365 if (len <= 0) 2366 return -EINVAL; 2367 2368 if (!tp->repair) 2369 return -EPERM; 2370 2371 rcu_read_lock(); 2372 ao = getsockopt_ao_info(sk); 2373 if (IS_ERR_OR_NULL(ao)) { 2374 rcu_read_unlock(); 2375 return ao ? PTR_ERR(ao) : -ENOENT; 2376 } 2377 2378 opt.snt_isn = ao->lisn; 2379 opt.rcv_isn = ao->risn; 2380 opt.snd_sne = READ_ONCE(ao->snd_sne); 2381 opt.rcv_sne = READ_ONCE(ao->rcv_sne); 2382 rcu_read_unlock(); 2383 2384 if (copy_to_sockptr(optval, &opt, min_t(int, len, sizeof(opt)))) 2385 return -EFAULT; 2386 return 0; 2387 } 2388