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