1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C)2002 USAGI/WIDE Project 4 * 5 * Authors 6 * 7 * Mitsuru KANDA @USAGI : IPv6 Support 8 * Kazunori MIYAZAWA @USAGI : 9 * Kunihiro Ishiguro <kunihiro@ipinfusion.com> 10 * 11 * This file is derived from net/ipv4/esp.c 12 */ 13 14 #define pr_fmt(fmt) "IPv6: " fmt 15 16 #include <crypto/aead.h> 17 #include <crypto/authenc.h> 18 #include <linux/err.h> 19 #include <linux/module.h> 20 #include <net/ip.h> 21 #include <net/xfrm.h> 22 #include <net/esp.h> 23 #include <linux/scatterlist.h> 24 #include <linux/kernel.h> 25 #include <linux/pfkeyv2.h> 26 #include <linux/random.h> 27 #include <linux/slab.h> 28 #include <linux/spinlock.h> 29 #include <net/ip6_checksum.h> 30 #include <net/ip6_route.h> 31 #include <net/icmp.h> 32 #include <net/ipv6.h> 33 #include <net/protocol.h> 34 #include <net/udp.h> 35 #include <linux/icmpv6.h> 36 #include <net/tcp.h> 37 #include <net/espintcp.h> 38 #include <net/inet6_hashtables.h> 39 40 #include <linux/highmem.h> 41 42 struct esp_skb_cb { 43 struct xfrm_skb_cb xfrm; 44 void *tmp; 45 }; 46 47 struct esp_output_extra { 48 __be32 seqhi; 49 u32 esphoff; 50 }; 51 52 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0])) 53 54 /* 55 * Allocate an AEAD request structure with extra space for SG and IV. 56 * 57 * For alignment considerations the upper 32 bits of the sequence number are 58 * placed at the front, if present. Followed by the IV, the request and finally 59 * the SG list. 60 * 61 * TODO: Use spare space in skb for this where possible. 62 */ 63 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen) 64 { 65 unsigned int len; 66 67 len = seqihlen; 68 69 len += crypto_aead_ivsize(aead); 70 71 if (len) { 72 len += crypto_aead_alignmask(aead) & 73 ~(crypto_tfm_ctx_alignment() - 1); 74 len = ALIGN(len, crypto_tfm_ctx_alignment()); 75 } 76 77 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead); 78 len = ALIGN(len, __alignof__(struct scatterlist)); 79 80 len += sizeof(struct scatterlist) * nfrags; 81 82 return kmalloc(len, GFP_ATOMIC); 83 } 84 85 static inline void *esp_tmp_extra(void *tmp) 86 { 87 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra)); 88 } 89 90 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen) 91 { 92 return crypto_aead_ivsize(aead) ? 93 PTR_ALIGN((u8 *)tmp + seqhilen, 94 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen; 95 } 96 97 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv) 98 { 99 struct aead_request *req; 100 101 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead), 102 crypto_tfm_ctx_alignment()); 103 aead_request_set_tfm(req, aead); 104 return req; 105 } 106 107 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead, 108 struct aead_request *req) 109 { 110 return (void *)ALIGN((unsigned long)(req + 1) + 111 crypto_aead_reqsize(aead), 112 __alignof__(struct scatterlist)); 113 } 114 115 static void esp_ssg_unref(struct xfrm_state *x, void *tmp) 116 { 117 struct crypto_aead *aead = x->data; 118 int extralen = 0; 119 u8 *iv; 120 struct aead_request *req; 121 struct scatterlist *sg; 122 123 if (x->props.flags & XFRM_STATE_ESN) 124 extralen += sizeof(struct esp_output_extra); 125 126 iv = esp_tmp_iv(aead, tmp, extralen); 127 req = esp_tmp_req(aead, iv); 128 129 /* Unref skb_frag_pages in the src scatterlist if necessary. 130 * Skip the first sg which comes from skb->data. 131 */ 132 if (req->src != req->dst) 133 for (sg = sg_next(req->src); sg; sg = sg_next(sg)) 134 put_page(sg_page(sg)); 135 } 136 137 #ifdef CONFIG_INET6_ESPINTCP 138 struct esp_tcp_sk { 139 struct sock *sk; 140 struct rcu_head rcu; 141 }; 142 143 static void esp_free_tcp_sk(struct rcu_head *head) 144 { 145 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu); 146 147 sock_put(esk->sk); 148 kfree(esk); 149 } 150 151 static struct sock *esp6_find_tcp_sk(struct xfrm_state *x) 152 { 153 struct xfrm_encap_tmpl *encap = x->encap; 154 struct net *net = xs_net(x); 155 struct esp_tcp_sk *esk; 156 __be16 sport, dport; 157 struct sock *nsk; 158 struct sock *sk; 159 160 sk = rcu_dereference(x->encap_sk); 161 if (sk && sk->sk_state == TCP_ESTABLISHED) 162 return sk; 163 164 spin_lock_bh(&x->lock); 165 sport = encap->encap_sport; 166 dport = encap->encap_dport; 167 nsk = rcu_dereference_protected(x->encap_sk, 168 lockdep_is_held(&x->lock)); 169 if (sk && sk == nsk) { 170 esk = kmalloc(sizeof(*esk), GFP_ATOMIC); 171 if (!esk) { 172 spin_unlock_bh(&x->lock); 173 return ERR_PTR(-ENOMEM); 174 } 175 RCU_INIT_POINTER(x->encap_sk, NULL); 176 esk->sk = sk; 177 call_rcu(&esk->rcu, esp_free_tcp_sk); 178 } 179 spin_unlock_bh(&x->lock); 180 181 sk = __inet6_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, &x->id.daddr.in6, 182 dport, &x->props.saddr.in6, ntohs(sport), 0, 0); 183 if (!sk) 184 return ERR_PTR(-ENOENT); 185 186 if (!tcp_is_ulp_esp(sk)) { 187 sock_put(sk); 188 return ERR_PTR(-EINVAL); 189 } 190 191 spin_lock_bh(&x->lock); 192 nsk = rcu_dereference_protected(x->encap_sk, 193 lockdep_is_held(&x->lock)); 194 if (encap->encap_sport != sport || 195 encap->encap_dport != dport) { 196 sock_put(sk); 197 sk = nsk ?: ERR_PTR(-EREMCHG); 198 } else if (sk == nsk) { 199 sock_put(sk); 200 } else { 201 rcu_assign_pointer(x->encap_sk, sk); 202 } 203 spin_unlock_bh(&x->lock); 204 205 return sk; 206 } 207 208 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) 209 { 210 struct sock *sk; 211 int err; 212 213 rcu_read_lock(); 214 215 sk = esp6_find_tcp_sk(x); 216 err = PTR_ERR_OR_ZERO(sk); 217 if (err) 218 goto out; 219 220 bh_lock_sock(sk); 221 if (sock_owned_by_user(sk)) 222 err = espintcp_queue_out(sk, skb); 223 else 224 err = espintcp_push_skb(sk, skb); 225 bh_unlock_sock(sk); 226 227 out: 228 rcu_read_unlock(); 229 return err; 230 } 231 232 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk, 233 struct sk_buff *skb) 234 { 235 struct dst_entry *dst = skb_dst(skb); 236 struct xfrm_state *x = dst->xfrm; 237 238 return esp_output_tcp_finish(x, skb); 239 } 240 241 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 242 { 243 int err; 244 245 local_bh_disable(); 246 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb); 247 local_bh_enable(); 248 249 /* EINPROGRESS just happens to do the right thing. It 250 * actually means that the skb has been consumed and 251 * isn't coming back. 252 */ 253 return err ?: -EINPROGRESS; 254 } 255 #else 256 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 257 { 258 kfree_skb(skb); 259 260 return -EOPNOTSUPP; 261 } 262 #endif 263 264 static void esp_output_encap_csum(struct sk_buff *skb) 265 { 266 /* UDP encap with IPv6 requires a valid checksum */ 267 if (*skb_mac_header(skb) == IPPROTO_UDP) { 268 struct udphdr *uh = udp_hdr(skb); 269 struct ipv6hdr *ip6h = ipv6_hdr(skb); 270 int len = ntohs(uh->len); 271 unsigned int offset = skb_transport_offset(skb); 272 __wsum csum = skb_checksum(skb, offset, skb->len - offset, 0); 273 274 uh->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, 275 len, IPPROTO_UDP, csum); 276 if (uh->check == 0) 277 uh->check = CSUM_MANGLED_0; 278 } 279 } 280 281 static void esp_output_done(void *data, int err) 282 { 283 struct sk_buff *skb = data; 284 struct xfrm_offload *xo = xfrm_offload(skb); 285 void *tmp; 286 struct xfrm_state *x; 287 288 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 289 struct sec_path *sp = skb_sec_path(skb); 290 291 x = sp->xvec[sp->len - 1]; 292 } else { 293 x = skb_dst(skb)->xfrm; 294 } 295 296 tmp = ESP_SKB_CB(skb)->tmp; 297 esp_ssg_unref(x, tmp); 298 kfree(tmp); 299 300 esp_output_encap_csum(skb); 301 302 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 303 if (err) { 304 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR); 305 kfree_skb(skb); 306 return; 307 } 308 309 skb_push(skb, skb->data - skb_mac_header(skb)); 310 secpath_reset(skb); 311 xfrm_dev_resume(skb); 312 } else { 313 if (!err && 314 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 315 esp_output_tail_tcp(x, skb); 316 else 317 xfrm_output_resume(skb->sk, skb, err); 318 } 319 } 320 321 /* Move ESP header back into place. */ 322 static void esp_restore_header(struct sk_buff *skb, unsigned int offset) 323 { 324 struct ip_esp_hdr *esph = (void *)(skb->data + offset); 325 void *tmp = ESP_SKB_CB(skb)->tmp; 326 __be32 *seqhi = esp_tmp_extra(tmp); 327 328 esph->seq_no = esph->spi; 329 esph->spi = *seqhi; 330 } 331 332 static void esp_output_restore_header(struct sk_buff *skb) 333 { 334 void *tmp = ESP_SKB_CB(skb)->tmp; 335 struct esp_output_extra *extra = esp_tmp_extra(tmp); 336 337 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff - 338 sizeof(__be32)); 339 } 340 341 static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb, 342 struct xfrm_state *x, 343 struct ip_esp_hdr *esph, 344 struct esp_output_extra *extra) 345 { 346 /* For ESN we move the header forward by 4 bytes to 347 * accommodate the high bits. We will move it back after 348 * encryption. 349 */ 350 if ((x->props.flags & XFRM_STATE_ESN)) { 351 __u32 seqhi; 352 struct xfrm_offload *xo = xfrm_offload(skb); 353 354 if (xo) 355 seqhi = xo->seq.hi; 356 else 357 seqhi = XFRM_SKB_CB(skb)->seq.output.hi; 358 359 extra->esphoff = (unsigned char *)esph - 360 skb_transport_header(skb); 361 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4); 362 extra->seqhi = esph->spi; 363 esph->seq_no = htonl(seqhi); 364 } 365 366 esph->spi = x->id.spi; 367 368 return esph; 369 } 370 371 static void esp_output_done_esn(void *data, int err) 372 { 373 struct sk_buff *skb = data; 374 375 esp_output_restore_header(skb); 376 esp_output_done(data, err); 377 } 378 379 static struct ip_esp_hdr *esp6_output_udp_encap(struct sk_buff *skb, 380 int encap_type, 381 struct esp_info *esp, 382 __be16 sport, 383 __be16 dport) 384 { 385 struct udphdr *uh; 386 __be32 *udpdata32; 387 unsigned int len; 388 389 len = skb->len + esp->tailen - skb_transport_offset(skb); 390 if (len > U16_MAX) 391 return ERR_PTR(-EMSGSIZE); 392 393 uh = (struct udphdr *)esp->esph; 394 uh->source = sport; 395 uh->dest = dport; 396 uh->len = htons(len); 397 uh->check = 0; 398 399 *skb_mac_header(skb) = IPPROTO_UDP; 400 401 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) { 402 udpdata32 = (__be32 *)(uh + 1); 403 udpdata32[0] = udpdata32[1] = 0; 404 return (struct ip_esp_hdr *)(udpdata32 + 2); 405 } 406 407 return (struct ip_esp_hdr *)(uh + 1); 408 } 409 410 #ifdef CONFIG_INET6_ESPINTCP 411 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x, 412 struct sk_buff *skb, 413 struct esp_info *esp) 414 { 415 __be16 *lenp = (void *)esp->esph; 416 struct ip_esp_hdr *esph; 417 unsigned int len; 418 struct sock *sk; 419 420 len = skb->len + esp->tailen - skb_transport_offset(skb); 421 if (len > IP_MAX_MTU) 422 return ERR_PTR(-EMSGSIZE); 423 424 rcu_read_lock(); 425 sk = esp6_find_tcp_sk(x); 426 rcu_read_unlock(); 427 428 if (IS_ERR(sk)) 429 return ERR_CAST(sk); 430 431 *lenp = htons(len); 432 esph = (struct ip_esp_hdr *)(lenp + 1); 433 434 return esph; 435 } 436 #else 437 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x, 438 struct sk_buff *skb, 439 struct esp_info *esp) 440 { 441 return ERR_PTR(-EOPNOTSUPP); 442 } 443 #endif 444 445 static int esp6_output_encap(struct xfrm_state *x, struct sk_buff *skb, 446 struct esp_info *esp) 447 { 448 struct xfrm_encap_tmpl *encap = x->encap; 449 struct ip_esp_hdr *esph; 450 __be16 sport, dport; 451 int encap_type; 452 453 spin_lock_bh(&x->lock); 454 sport = encap->encap_sport; 455 dport = encap->encap_dport; 456 encap_type = encap->encap_type; 457 spin_unlock_bh(&x->lock); 458 459 switch (encap_type) { 460 default: 461 case UDP_ENCAP_ESPINUDP: 462 case UDP_ENCAP_ESPINUDP_NON_IKE: 463 esph = esp6_output_udp_encap(skb, encap_type, esp, sport, dport); 464 break; 465 case TCP_ENCAP_ESPINTCP: 466 esph = esp6_output_tcp_encap(x, skb, esp); 467 break; 468 } 469 470 if (IS_ERR(esph)) 471 return PTR_ERR(esph); 472 473 esp->esph = esph; 474 475 return 0; 476 } 477 478 int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 479 { 480 u8 *tail; 481 int nfrags; 482 int esph_offset; 483 struct page *page; 484 struct sk_buff *trailer; 485 int tailen = esp->tailen; 486 487 if (x->encap) { 488 int err = esp6_output_encap(x, skb, esp); 489 490 if (err < 0) 491 return err; 492 } 493 494 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE || 495 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE) 496 goto cow; 497 498 if (!skb_cloned(skb)) { 499 if (tailen <= skb_tailroom(skb)) { 500 nfrags = 1; 501 trailer = skb; 502 tail = skb_tail_pointer(trailer); 503 504 goto skip_cow; 505 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 506 && !skb_has_frag_list(skb)) { 507 int allocsize; 508 struct sock *sk = skb->sk; 509 struct page_frag *pfrag = &x->xfrag; 510 511 esp->inplace = false; 512 513 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 514 515 spin_lock_bh(&x->lock); 516 517 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 518 spin_unlock_bh(&x->lock); 519 goto cow; 520 } 521 522 page = pfrag->page; 523 get_page(page); 524 525 tail = page_address(page) + pfrag->offset; 526 527 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 528 529 nfrags = skb_shinfo(skb)->nr_frags; 530 531 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 532 tailen); 533 skb_shinfo(skb)->nr_frags = ++nfrags; 534 535 pfrag->offset = pfrag->offset + allocsize; 536 537 spin_unlock_bh(&x->lock); 538 539 nfrags++; 540 541 skb->len += tailen; 542 skb->data_len += tailen; 543 skb->truesize += tailen; 544 if (sk && sk_fullsock(sk)) 545 refcount_add(tailen, &sk->sk_wmem_alloc); 546 547 goto out; 548 } 549 } 550 551 cow: 552 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 553 554 nfrags = skb_cow_data(skb, tailen, &trailer); 555 if (nfrags < 0) 556 goto out; 557 tail = skb_tail_pointer(trailer); 558 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 559 560 skip_cow: 561 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 562 pskb_put(skb, trailer, tailen); 563 564 out: 565 return nfrags; 566 } 567 EXPORT_SYMBOL_GPL(esp6_output_head); 568 569 int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 570 { 571 u8 *iv; 572 int alen; 573 void *tmp; 574 int ivlen; 575 int assoclen; 576 int extralen; 577 struct page *page; 578 struct ip_esp_hdr *esph; 579 struct aead_request *req; 580 struct crypto_aead *aead; 581 struct scatterlist *sg, *dsg; 582 struct esp_output_extra *extra; 583 int err = -ENOMEM; 584 585 assoclen = sizeof(struct ip_esp_hdr); 586 extralen = 0; 587 588 if (x->props.flags & XFRM_STATE_ESN) { 589 extralen += sizeof(*extra); 590 assoclen += sizeof(__be32); 591 } 592 593 aead = x->data; 594 alen = crypto_aead_authsize(aead); 595 ivlen = crypto_aead_ivsize(aead); 596 597 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 598 if (!tmp) 599 goto error; 600 601 extra = esp_tmp_extra(tmp); 602 iv = esp_tmp_iv(aead, tmp, extralen); 603 req = esp_tmp_req(aead, iv); 604 sg = esp_req_sg(aead, req); 605 606 if (esp->inplace) 607 dsg = sg; 608 else 609 dsg = &sg[esp->nfrags]; 610 611 esph = esp_output_set_esn(skb, x, esp->esph, extra); 612 esp->esph = esph; 613 614 sg_init_table(sg, esp->nfrags); 615 err = skb_to_sgvec(skb, sg, 616 (unsigned char *)esph - skb->data, 617 assoclen + ivlen + esp->clen + alen); 618 if (unlikely(err < 0)) 619 goto error_free; 620 621 if (!esp->inplace) { 622 int allocsize; 623 struct page_frag *pfrag = &x->xfrag; 624 625 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 626 627 spin_lock_bh(&x->lock); 628 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 629 spin_unlock_bh(&x->lock); 630 goto error_free; 631 } 632 633 skb_shinfo(skb)->nr_frags = 1; 634 635 page = pfrag->page; 636 get_page(page); 637 /* replace page frags in skb with new page */ 638 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 639 pfrag->offset = pfrag->offset + allocsize; 640 spin_unlock_bh(&x->lock); 641 642 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 643 err = skb_to_sgvec(skb, dsg, 644 (unsigned char *)esph - skb->data, 645 assoclen + ivlen + esp->clen + alen); 646 if (unlikely(err < 0)) 647 goto error_free; 648 } 649 650 if ((x->props.flags & XFRM_STATE_ESN)) 651 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 652 else 653 aead_request_set_callback(req, 0, esp_output_done, skb); 654 655 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 656 aead_request_set_ad(req, assoclen); 657 658 memset(iv, 0, ivlen); 659 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 660 min(ivlen, 8)); 661 662 ESP_SKB_CB(skb)->tmp = tmp; 663 err = crypto_aead_encrypt(req); 664 665 switch (err) { 666 case -EINPROGRESS: 667 goto error; 668 669 case -ENOSPC: 670 err = NET_XMIT_DROP; 671 break; 672 673 case 0: 674 if ((x->props.flags & XFRM_STATE_ESN)) 675 esp_output_restore_header(skb); 676 esp_output_encap_csum(skb); 677 } 678 679 if (sg != dsg) 680 esp_ssg_unref(x, tmp); 681 682 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 683 err = esp_output_tail_tcp(x, skb); 684 685 error_free: 686 kfree(tmp); 687 error: 688 return err; 689 } 690 EXPORT_SYMBOL_GPL(esp6_output_tail); 691 692 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) 693 { 694 int alen; 695 int blksize; 696 struct ip_esp_hdr *esph; 697 struct crypto_aead *aead; 698 struct esp_info esp; 699 700 esp.inplace = true; 701 702 esp.proto = *skb_mac_header(skb); 703 *skb_mac_header(skb) = IPPROTO_ESP; 704 705 /* skb is pure payload to encrypt */ 706 707 aead = x->data; 708 alen = crypto_aead_authsize(aead); 709 710 esp.tfclen = 0; 711 if (x->tfcpad) { 712 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 713 u32 padto; 714 715 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 716 if (skb->len < padto) 717 esp.tfclen = padto - skb->len; 718 } 719 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 720 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 721 esp.plen = esp.clen - skb->len - esp.tfclen; 722 esp.tailen = esp.tfclen + esp.plen + alen; 723 724 esp.esph = ip_esp_hdr(skb); 725 726 esp.nfrags = esp6_output_head(x, skb, &esp); 727 if (esp.nfrags < 0) 728 return esp.nfrags; 729 730 esph = esp.esph; 731 esph->spi = x->id.spi; 732 733 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 734 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 735 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 736 737 skb_push(skb, -skb_network_offset(skb)); 738 739 return esp6_output_tail(x, skb, &esp); 740 } 741 742 static inline int esp_remove_trailer(struct sk_buff *skb) 743 { 744 struct xfrm_state *x = xfrm_input_state(skb); 745 struct crypto_aead *aead = x->data; 746 int alen, hlen, elen; 747 int padlen, trimlen; 748 __wsum csumdiff; 749 u8 nexthdr[2]; 750 int ret; 751 752 alen = crypto_aead_authsize(aead); 753 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 754 elen = skb->len - hlen; 755 756 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2); 757 BUG_ON(ret); 758 759 ret = -EINVAL; 760 padlen = nexthdr[0]; 761 if (padlen + 2 + alen >= elen) { 762 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 763 padlen + 2, elen - alen); 764 goto out; 765 } 766 767 trimlen = alen + padlen + 2; 768 if (skb->ip_summed == CHECKSUM_COMPLETE) { 769 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 770 skb->csum = csum_block_sub(skb->csum, csumdiff, 771 skb->len - trimlen); 772 } 773 pskb_trim(skb, skb->len - trimlen); 774 775 ret = nexthdr[1]; 776 777 out: 778 return ret; 779 } 780 781 int esp6_input_done2(struct sk_buff *skb, int err) 782 { 783 struct xfrm_state *x = xfrm_input_state(skb); 784 struct xfrm_offload *xo = xfrm_offload(skb); 785 struct crypto_aead *aead = x->data; 786 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 787 int hdr_len = skb_network_header_len(skb); 788 789 if (!xo || !(xo->flags & CRYPTO_DONE)) 790 kfree(ESP_SKB_CB(skb)->tmp); 791 792 if (unlikely(err)) 793 goto out; 794 795 err = esp_remove_trailer(skb); 796 if (unlikely(err < 0)) 797 goto out; 798 799 if (x->encap) { 800 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 801 int offset = skb_network_offset(skb) + sizeof(*ip6h); 802 struct xfrm_encap_tmpl *encap = x->encap; 803 u8 nexthdr = ip6h->nexthdr; 804 __be16 frag_off, source; 805 struct udphdr *uh; 806 struct tcphdr *th; 807 808 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); 809 if (offset == -1) { 810 err = -EINVAL; 811 goto out; 812 } 813 814 uh = (void *)(skb->data + offset); 815 th = (void *)(skb->data + offset); 816 hdr_len += offset; 817 818 switch (x->encap->encap_type) { 819 case TCP_ENCAP_ESPINTCP: 820 source = th->source; 821 break; 822 case UDP_ENCAP_ESPINUDP: 823 case UDP_ENCAP_ESPINUDP_NON_IKE: 824 source = uh->source; 825 break; 826 default: 827 WARN_ON_ONCE(1); 828 err = -EINVAL; 829 goto out; 830 } 831 832 /* 833 * 1) if the NAT-T peer's IP or port changed then 834 * advertize the change to the keying daemon. 835 * This is an inbound SA, so just compare 836 * SRC ports. 837 */ 838 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) || 839 source != encap->encap_sport) { 840 xfrm_address_t ipaddr; 841 842 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6)); 843 km_new_mapping(x, &ipaddr, source); 844 845 /* XXX: perhaps add an extra 846 * policy check here, to see 847 * if we should allow or 848 * reject a packet from a 849 * different source 850 * address/port. 851 */ 852 } 853 854 /* 855 * 2) ignore UDP/TCP checksums in case 856 * of NAT-T in Transport Mode, or 857 * perform other post-processing fixes 858 * as per draft-ietf-ipsec-udp-encaps-06, 859 * section 3.1.2 860 */ 861 if (x->props.mode == XFRM_MODE_TRANSPORT) 862 skb->ip_summed = CHECKSUM_UNNECESSARY; 863 } 864 865 skb_postpull_rcsum(skb, skb_network_header(skb), 866 skb_network_header_len(skb)); 867 skb_pull_rcsum(skb, hlen); 868 if (x->props.mode == XFRM_MODE_TUNNEL) 869 skb_reset_transport_header(skb); 870 else 871 skb_set_transport_header(skb, -hdr_len); 872 873 /* RFC4303: Drop dummy packets without any error */ 874 if (err == IPPROTO_NONE) 875 err = -EINVAL; 876 877 out: 878 return err; 879 } 880 EXPORT_SYMBOL_GPL(esp6_input_done2); 881 882 static void esp_input_done(void *data, int err) 883 { 884 struct sk_buff *skb = data; 885 886 xfrm_input_resume(skb, esp6_input_done2(skb, err)); 887 } 888 889 static void esp_input_restore_header(struct sk_buff *skb) 890 { 891 esp_restore_header(skb, 0); 892 __skb_pull(skb, 4); 893 } 894 895 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 896 { 897 struct xfrm_state *x = xfrm_input_state(skb); 898 899 /* For ESN we move the header forward by 4 bytes to 900 * accommodate the high bits. We will move it back after 901 * decryption. 902 */ 903 if ((x->props.flags & XFRM_STATE_ESN)) { 904 struct ip_esp_hdr *esph = skb_push(skb, 4); 905 906 *seqhi = esph->spi; 907 esph->spi = esph->seq_no; 908 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 909 } 910 } 911 912 static void esp_input_done_esn(void *data, int err) 913 { 914 struct sk_buff *skb = data; 915 916 esp_input_restore_header(skb); 917 esp_input_done(data, err); 918 } 919 920 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) 921 { 922 struct crypto_aead *aead = x->data; 923 struct aead_request *req; 924 struct sk_buff *trailer; 925 int ivlen = crypto_aead_ivsize(aead); 926 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 927 int nfrags; 928 int assoclen; 929 int seqhilen; 930 int ret = 0; 931 void *tmp; 932 __be32 *seqhi; 933 u8 *iv; 934 struct scatterlist *sg; 935 936 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) { 937 ret = -EINVAL; 938 goto out; 939 } 940 941 if (elen <= 0) { 942 ret = -EINVAL; 943 goto out; 944 } 945 946 assoclen = sizeof(struct ip_esp_hdr); 947 seqhilen = 0; 948 949 if (x->props.flags & XFRM_STATE_ESN) { 950 seqhilen += sizeof(__be32); 951 assoclen += seqhilen; 952 } 953 954 if (!skb_cloned(skb)) { 955 if (!skb_is_nonlinear(skb)) { 956 nfrags = 1; 957 958 goto skip_cow; 959 } else if (!skb_has_frag_list(skb)) { 960 nfrags = skb_shinfo(skb)->nr_frags; 961 nfrags++; 962 963 goto skip_cow; 964 } 965 } 966 967 nfrags = skb_cow_data(skb, 0, &trailer); 968 if (nfrags < 0) { 969 ret = -EINVAL; 970 goto out; 971 } 972 973 skip_cow: 974 ret = -ENOMEM; 975 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 976 if (!tmp) 977 goto out; 978 979 ESP_SKB_CB(skb)->tmp = tmp; 980 seqhi = esp_tmp_extra(tmp); 981 iv = esp_tmp_iv(aead, tmp, seqhilen); 982 req = esp_tmp_req(aead, iv); 983 sg = esp_req_sg(aead, req); 984 985 esp_input_set_header(skb, seqhi); 986 987 sg_init_table(sg, nfrags); 988 ret = skb_to_sgvec(skb, sg, 0, skb->len); 989 if (unlikely(ret < 0)) { 990 kfree(tmp); 991 goto out; 992 } 993 994 skb->ip_summed = CHECKSUM_NONE; 995 996 if ((x->props.flags & XFRM_STATE_ESN)) 997 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 998 else 999 aead_request_set_callback(req, 0, esp_input_done, skb); 1000 1001 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 1002 aead_request_set_ad(req, assoclen); 1003 1004 ret = crypto_aead_decrypt(req); 1005 if (ret == -EINPROGRESS) 1006 goto out; 1007 1008 if ((x->props.flags & XFRM_STATE_ESN)) 1009 esp_input_restore_header(skb); 1010 1011 ret = esp6_input_done2(skb, ret); 1012 1013 out: 1014 return ret; 1015 } 1016 1017 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 1018 u8 type, u8 code, int offset, __be32 info) 1019 { 1020 struct net *net = dev_net(skb->dev); 1021 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 1022 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset); 1023 struct xfrm_state *x; 1024 1025 if (type != ICMPV6_PKT_TOOBIG && 1026 type != NDISC_REDIRECT) 1027 return 0; 1028 1029 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 1030 esph->spi, IPPROTO_ESP, AF_INET6); 1031 if (!x) 1032 return 0; 1033 1034 if (type == NDISC_REDIRECT) 1035 ip6_redirect(skb, net, skb->dev->ifindex, 0, 1036 sock_net_uid(net, NULL)); 1037 else 1038 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 1039 xfrm_state_put(x); 1040 1041 return 0; 1042 } 1043 1044 static void esp6_destroy(struct xfrm_state *x) 1045 { 1046 struct crypto_aead *aead = x->data; 1047 1048 if (!aead) 1049 return; 1050 1051 crypto_free_aead(aead); 1052 } 1053 1054 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 1055 { 1056 char aead_name[CRYPTO_MAX_ALG_NAME]; 1057 struct crypto_aead *aead; 1058 int err; 1059 1060 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1061 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 1062 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1063 return -ENAMETOOLONG; 1064 } 1065 1066 aead = crypto_alloc_aead(aead_name, 0, 0); 1067 err = PTR_ERR(aead); 1068 if (IS_ERR(aead)) 1069 goto error; 1070 1071 x->data = aead; 1072 1073 err = crypto_aead_setkey(aead, x->aead->alg_key, 1074 (x->aead->alg_key_len + 7) / 8); 1075 if (err) 1076 goto error; 1077 1078 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1079 if (err) 1080 goto error; 1081 1082 return 0; 1083 1084 error: 1085 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1086 return err; 1087 } 1088 1089 static int esp_init_authenc(struct xfrm_state *x, 1090 struct netlink_ext_ack *extack) 1091 { 1092 struct crypto_aead *aead; 1093 struct crypto_authenc_key_param *param; 1094 struct rtattr *rta; 1095 char *key; 1096 char *p; 1097 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1098 unsigned int keylen; 1099 int err; 1100 1101 err = -ENAMETOOLONG; 1102 1103 if ((x->props.flags & XFRM_STATE_ESN)) { 1104 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1105 "%s%sauthencesn(%s,%s)%s", 1106 x->geniv ?: "", x->geniv ? "(" : "", 1107 x->aalg ? x->aalg->alg_name : "digest_null", 1108 x->ealg->alg_name, 1109 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1110 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1111 goto error; 1112 } 1113 } else { 1114 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1115 "%s%sauthenc(%s,%s)%s", 1116 x->geniv ?: "", x->geniv ? "(" : "", 1117 x->aalg ? x->aalg->alg_name : "digest_null", 1118 x->ealg->alg_name, 1119 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1120 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1121 goto error; 1122 } 1123 } 1124 1125 aead = crypto_alloc_aead(authenc_name, 0, 0); 1126 err = PTR_ERR(aead); 1127 if (IS_ERR(aead)) { 1128 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1129 goto error; 1130 } 1131 1132 x->data = aead; 1133 1134 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1135 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1136 err = -ENOMEM; 1137 key = kmalloc(keylen, GFP_KERNEL); 1138 if (!key) 1139 goto error; 1140 1141 p = key; 1142 rta = (void *)p; 1143 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1144 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1145 param = RTA_DATA(rta); 1146 p += RTA_SPACE(sizeof(*param)); 1147 1148 if (x->aalg) { 1149 struct xfrm_algo_desc *aalg_desc; 1150 1151 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1152 p += (x->aalg->alg_key_len + 7) / 8; 1153 1154 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1155 BUG_ON(!aalg_desc); 1156 1157 err = -EINVAL; 1158 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1159 crypto_aead_authsize(aead)) { 1160 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1161 goto free_key; 1162 } 1163 1164 err = crypto_aead_setauthsize( 1165 aead, x->aalg->alg_trunc_len / 8); 1166 if (err) { 1167 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1168 goto free_key; 1169 } 1170 } 1171 1172 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1173 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1174 1175 err = crypto_aead_setkey(aead, key, keylen); 1176 1177 free_key: 1178 kfree(key); 1179 1180 error: 1181 return err; 1182 } 1183 1184 static int esp6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1185 { 1186 struct crypto_aead *aead; 1187 u32 align; 1188 int err; 1189 1190 x->data = NULL; 1191 1192 if (x->aead) { 1193 err = esp_init_aead(x, extack); 1194 } else if (x->ealg) { 1195 err = esp_init_authenc(x, extack); 1196 } else { 1197 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1198 err = -EINVAL; 1199 } 1200 1201 if (err) 1202 goto error; 1203 1204 aead = x->data; 1205 1206 x->props.header_len = sizeof(struct ip_esp_hdr) + 1207 crypto_aead_ivsize(aead); 1208 switch (x->props.mode) { 1209 case XFRM_MODE_BEET: 1210 if (x->sel.family != AF_INET6) 1211 x->props.header_len += IPV4_BEET_PHMAXLEN + 1212 (sizeof(struct ipv6hdr) - sizeof(struct iphdr)); 1213 break; 1214 default: 1215 case XFRM_MODE_TRANSPORT: 1216 break; 1217 case XFRM_MODE_TUNNEL: 1218 x->props.header_len += sizeof(struct ipv6hdr); 1219 break; 1220 } 1221 1222 if (x->encap) { 1223 struct xfrm_encap_tmpl *encap = x->encap; 1224 1225 switch (encap->encap_type) { 1226 default: 1227 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1228 err = -EINVAL; 1229 goto error; 1230 case UDP_ENCAP_ESPINUDP: 1231 x->props.header_len += sizeof(struct udphdr); 1232 break; 1233 case UDP_ENCAP_ESPINUDP_NON_IKE: 1234 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 1235 break; 1236 #ifdef CONFIG_INET6_ESPINTCP 1237 case TCP_ENCAP_ESPINTCP: 1238 /* only the length field, TCP encap is done by 1239 * the socket 1240 */ 1241 x->props.header_len += 2; 1242 break; 1243 #endif 1244 } 1245 } 1246 1247 align = ALIGN(crypto_aead_blocksize(aead), 4); 1248 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1249 1250 error: 1251 return err; 1252 } 1253 1254 static int esp6_rcv_cb(struct sk_buff *skb, int err) 1255 { 1256 return 0; 1257 } 1258 1259 static const struct xfrm_type esp6_type = { 1260 .owner = THIS_MODULE, 1261 .proto = IPPROTO_ESP, 1262 .flags = XFRM_TYPE_REPLAY_PROT, 1263 .init_state = esp6_init_state, 1264 .destructor = esp6_destroy, 1265 .input = esp6_input, 1266 .output = esp6_output, 1267 }; 1268 1269 static struct xfrm6_protocol esp6_protocol = { 1270 .handler = xfrm6_rcv, 1271 .input_handler = xfrm_input, 1272 .cb_handler = esp6_rcv_cb, 1273 .err_handler = esp6_err, 1274 .priority = 0, 1275 }; 1276 1277 static int __init esp6_init(void) 1278 { 1279 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { 1280 pr_info("%s: can't add xfrm type\n", __func__); 1281 return -EAGAIN; 1282 } 1283 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) { 1284 pr_info("%s: can't add protocol\n", __func__); 1285 xfrm_unregister_type(&esp6_type, AF_INET6); 1286 return -EAGAIN; 1287 } 1288 1289 return 0; 1290 } 1291 1292 static void __exit esp6_fini(void) 1293 { 1294 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0) 1295 pr_info("%s: can't remove protocol\n", __func__); 1296 xfrm_unregister_type(&esp6_type, AF_INET6); 1297 } 1298 1299 module_init(esp6_init); 1300 module_exit(esp6_fini); 1301 1302 MODULE_LICENSE("GPL"); 1303 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP); 1304