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(sg_page(sg), skb->pp_recycle); 136 } 137 138 #ifdef CONFIG_INET6_ESPINTCP 139 struct esp_tcp_sk { 140 struct sock *sk; 141 struct rcu_head rcu; 142 }; 143 144 static void esp_free_tcp_sk(struct rcu_head *head) 145 { 146 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu); 147 148 sock_put(esk->sk); 149 kfree(esk); 150 } 151 152 static struct sock *esp6_find_tcp_sk(struct xfrm_state *x) 153 { 154 struct xfrm_encap_tmpl *encap = x->encap; 155 struct net *net = xs_net(x); 156 struct esp_tcp_sk *esk; 157 __be16 sport, dport; 158 struct sock *nsk; 159 struct sock *sk; 160 161 sk = rcu_dereference(x->encap_sk); 162 if (sk && sk->sk_state == TCP_ESTABLISHED) 163 return sk; 164 165 spin_lock_bh(&x->lock); 166 sport = encap->encap_sport; 167 dport = encap->encap_dport; 168 nsk = rcu_dereference_protected(x->encap_sk, 169 lockdep_is_held(&x->lock)); 170 if (sk && sk == nsk) { 171 esk = kmalloc(sizeof(*esk), GFP_ATOMIC); 172 if (!esk) { 173 spin_unlock_bh(&x->lock); 174 return ERR_PTR(-ENOMEM); 175 } 176 RCU_INIT_POINTER(x->encap_sk, NULL); 177 esk->sk = sk; 178 call_rcu(&esk->rcu, esp_free_tcp_sk); 179 } 180 spin_unlock_bh(&x->lock); 181 182 sk = __inet6_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, &x->id.daddr.in6, 183 dport, &x->props.saddr.in6, ntohs(sport), 0, 0); 184 if (!sk) 185 return ERR_PTR(-ENOENT); 186 187 if (!tcp_is_ulp_esp(sk)) { 188 sock_put(sk); 189 return ERR_PTR(-EINVAL); 190 } 191 192 spin_lock_bh(&x->lock); 193 nsk = rcu_dereference_protected(x->encap_sk, 194 lockdep_is_held(&x->lock)); 195 if (encap->encap_sport != sport || 196 encap->encap_dport != dport) { 197 sock_put(sk); 198 sk = nsk ?: ERR_PTR(-EREMCHG); 199 } else if (sk == nsk) { 200 sock_put(sk); 201 } else { 202 rcu_assign_pointer(x->encap_sk, sk); 203 } 204 spin_unlock_bh(&x->lock); 205 206 return sk; 207 } 208 209 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) 210 { 211 struct sock *sk; 212 int err; 213 214 rcu_read_lock(); 215 216 sk = esp6_find_tcp_sk(x); 217 err = PTR_ERR_OR_ZERO(sk); 218 if (err) 219 goto out; 220 221 bh_lock_sock(sk); 222 if (sock_owned_by_user(sk)) 223 err = espintcp_queue_out(sk, skb); 224 else 225 err = espintcp_push_skb(sk, skb); 226 bh_unlock_sock(sk); 227 228 out: 229 rcu_read_unlock(); 230 return err; 231 } 232 233 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk, 234 struct sk_buff *skb) 235 { 236 struct dst_entry *dst = skb_dst(skb); 237 struct xfrm_state *x = dst->xfrm; 238 239 return esp_output_tcp_finish(x, skb); 240 } 241 242 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 243 { 244 int err; 245 246 local_bh_disable(); 247 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb); 248 local_bh_enable(); 249 250 /* EINPROGRESS just happens to do the right thing. It 251 * actually means that the skb has been consumed and 252 * isn't coming back. 253 */ 254 return err ?: -EINPROGRESS; 255 } 256 #else 257 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 258 { 259 kfree_skb(skb); 260 261 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 __be32 *udpdata32; 388 unsigned int len; 389 390 len = skb->len + esp->tailen - skb_transport_offset(skb); 391 if (len > U16_MAX) 392 return ERR_PTR(-EMSGSIZE); 393 394 uh = (struct udphdr *)esp->esph; 395 uh->source = sport; 396 uh->dest = dport; 397 uh->len = htons(len); 398 uh->check = 0; 399 400 *skb_mac_header(skb) = IPPROTO_UDP; 401 402 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) { 403 udpdata32 = (__be32 *)(uh + 1); 404 udpdata32[0] = udpdata32[1] = 0; 405 return (struct ip_esp_hdr *)(udpdata32 + 2); 406 } 407 408 return (struct ip_esp_hdr *)(uh + 1); 409 } 410 411 #ifdef CONFIG_INET6_ESPINTCP 412 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x, 413 struct sk_buff *skb, 414 struct esp_info *esp) 415 { 416 __be16 *lenp = (void *)esp->esph; 417 struct ip_esp_hdr *esph; 418 unsigned int len; 419 struct sock *sk; 420 421 len = skb->len + esp->tailen - skb_transport_offset(skb); 422 if (len > IP_MAX_MTU) 423 return ERR_PTR(-EMSGSIZE); 424 425 rcu_read_lock(); 426 sk = esp6_find_tcp_sk(x); 427 rcu_read_unlock(); 428 429 if (IS_ERR(sk)) 430 return ERR_CAST(sk); 431 432 *lenp = htons(len); 433 esph = (struct ip_esp_hdr *)(lenp + 1); 434 435 return esph; 436 } 437 #else 438 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x, 439 struct sk_buff *skb, 440 struct esp_info *esp) 441 { 442 return ERR_PTR(-EOPNOTSUPP); 443 } 444 #endif 445 446 static int esp6_output_encap(struct xfrm_state *x, struct sk_buff *skb, 447 struct esp_info *esp) 448 { 449 struct xfrm_encap_tmpl *encap = x->encap; 450 struct ip_esp_hdr *esph; 451 __be16 sport, dport; 452 int encap_type; 453 454 spin_lock_bh(&x->lock); 455 sport = encap->encap_sport; 456 dport = encap->encap_dport; 457 encap_type = encap->encap_type; 458 spin_unlock_bh(&x->lock); 459 460 switch (encap_type) { 461 default: 462 case UDP_ENCAP_ESPINUDP: 463 case UDP_ENCAP_ESPINUDP_NON_IKE: 464 esph = esp6_output_udp_encap(skb, encap_type, esp, sport, dport); 465 break; 466 case TCP_ENCAP_ESPINTCP: 467 esph = esp6_output_tcp_encap(x, skb, esp); 468 break; 469 } 470 471 if (IS_ERR(esph)) 472 return PTR_ERR(esph); 473 474 esp->esph = esph; 475 476 return 0; 477 } 478 479 int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 480 { 481 u8 *tail; 482 int nfrags; 483 int esph_offset; 484 struct page *page; 485 struct sk_buff *trailer; 486 int tailen = esp->tailen; 487 488 if (x->encap) { 489 int err = esp6_output_encap(x, skb, esp); 490 491 if (err < 0) 492 return err; 493 } 494 495 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE || 496 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE) 497 goto cow; 498 499 if (!skb_cloned(skb)) { 500 if (tailen <= skb_tailroom(skb)) { 501 nfrags = 1; 502 trailer = skb; 503 tail = skb_tail_pointer(trailer); 504 505 goto skip_cow; 506 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 507 && !skb_has_frag_list(skb)) { 508 int allocsize; 509 struct sock *sk = skb->sk; 510 struct page_frag *pfrag = &x->xfrag; 511 512 esp->inplace = false; 513 514 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 515 516 spin_lock_bh(&x->lock); 517 518 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 519 spin_unlock_bh(&x->lock); 520 goto cow; 521 } 522 523 page = pfrag->page; 524 get_page(page); 525 526 tail = page_address(page) + pfrag->offset; 527 528 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 529 530 nfrags = skb_shinfo(skb)->nr_frags; 531 532 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 533 tailen); 534 skb_shinfo(skb)->nr_frags = ++nfrags; 535 536 pfrag->offset = pfrag->offset + allocsize; 537 538 spin_unlock_bh(&x->lock); 539 540 nfrags++; 541 542 skb->len += tailen; 543 skb->data_len += tailen; 544 skb->truesize += tailen; 545 if (sk && sk_fullsock(sk)) 546 refcount_add(tailen, &sk->sk_wmem_alloc); 547 548 goto out; 549 } 550 } 551 552 cow: 553 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 554 555 nfrags = skb_cow_data(skb, tailen, &trailer); 556 if (nfrags < 0) 557 goto out; 558 tail = skb_tail_pointer(trailer); 559 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 560 561 skip_cow: 562 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 563 pskb_put(skb, trailer, tailen); 564 565 out: 566 return nfrags; 567 } 568 EXPORT_SYMBOL_GPL(esp6_output_head); 569 570 int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 571 { 572 u8 *iv; 573 int alen; 574 void *tmp; 575 int ivlen; 576 int assoclen; 577 int extralen; 578 struct page *page; 579 struct ip_esp_hdr *esph; 580 struct aead_request *req; 581 struct crypto_aead *aead; 582 struct scatterlist *sg, *dsg; 583 struct esp_output_extra *extra; 584 int err = -ENOMEM; 585 586 assoclen = sizeof(struct ip_esp_hdr); 587 extralen = 0; 588 589 if (x->props.flags & XFRM_STATE_ESN) { 590 extralen += sizeof(*extra); 591 assoclen += sizeof(__be32); 592 } 593 594 aead = x->data; 595 alen = crypto_aead_authsize(aead); 596 ivlen = crypto_aead_ivsize(aead); 597 598 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 599 if (!tmp) 600 goto error; 601 602 extra = esp_tmp_extra(tmp); 603 iv = esp_tmp_iv(aead, tmp, extralen); 604 req = esp_tmp_req(aead, iv); 605 sg = esp_req_sg(aead, req); 606 607 if (esp->inplace) 608 dsg = sg; 609 else 610 dsg = &sg[esp->nfrags]; 611 612 esph = esp_output_set_esn(skb, x, esp->esph, extra); 613 esp->esph = esph; 614 615 sg_init_table(sg, esp->nfrags); 616 err = skb_to_sgvec(skb, sg, 617 (unsigned char *)esph - skb->data, 618 assoclen + ivlen + esp->clen + alen); 619 if (unlikely(err < 0)) 620 goto error_free; 621 622 if (!esp->inplace) { 623 int allocsize; 624 struct page_frag *pfrag = &x->xfrag; 625 626 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 627 628 spin_lock_bh(&x->lock); 629 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 630 spin_unlock_bh(&x->lock); 631 goto error_free; 632 } 633 634 skb_shinfo(skb)->nr_frags = 1; 635 636 page = pfrag->page; 637 get_page(page); 638 /* replace page frags in skb with new page */ 639 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 640 pfrag->offset = pfrag->offset + allocsize; 641 spin_unlock_bh(&x->lock); 642 643 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 644 err = skb_to_sgvec(skb, dsg, 645 (unsigned char *)esph - skb->data, 646 assoclen + ivlen + esp->clen + alen); 647 if (unlikely(err < 0)) 648 goto error_free; 649 } 650 651 if ((x->props.flags & XFRM_STATE_ESN)) 652 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 653 else 654 aead_request_set_callback(req, 0, esp_output_done, skb); 655 656 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 657 aead_request_set_ad(req, assoclen); 658 659 memset(iv, 0, ivlen); 660 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 661 min(ivlen, 8)); 662 663 ESP_SKB_CB(skb)->tmp = tmp; 664 err = crypto_aead_encrypt(req); 665 666 switch (err) { 667 case -EINPROGRESS: 668 goto error; 669 670 case -ENOSPC: 671 err = NET_XMIT_DROP; 672 break; 673 674 case 0: 675 if ((x->props.flags & XFRM_STATE_ESN)) 676 esp_output_restore_header(skb); 677 esp_output_encap_csum(skb); 678 } 679 680 if (sg != dsg) 681 esp_ssg_unref(x, tmp, skb); 682 683 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 684 err = esp_output_tail_tcp(x, skb); 685 686 error_free: 687 kfree(tmp); 688 error: 689 return err; 690 } 691 EXPORT_SYMBOL_GPL(esp6_output_tail); 692 693 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) 694 { 695 int alen; 696 int blksize; 697 struct ip_esp_hdr *esph; 698 struct crypto_aead *aead; 699 struct esp_info esp; 700 701 esp.inplace = true; 702 703 esp.proto = *skb_mac_header(skb); 704 *skb_mac_header(skb) = IPPROTO_ESP; 705 706 /* skb is pure payload to encrypt */ 707 708 aead = x->data; 709 alen = crypto_aead_authsize(aead); 710 711 esp.tfclen = 0; 712 if (x->tfcpad) { 713 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 714 u32 padto; 715 716 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 717 if (skb->len < padto) 718 esp.tfclen = padto - skb->len; 719 } 720 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 721 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 722 esp.plen = esp.clen - skb->len - esp.tfclen; 723 esp.tailen = esp.tfclen + esp.plen + alen; 724 725 esp.esph = ip_esp_hdr(skb); 726 727 esp.nfrags = esp6_output_head(x, skb, &esp); 728 if (esp.nfrags < 0) 729 return esp.nfrags; 730 731 esph = esp.esph; 732 esph->spi = x->id.spi; 733 734 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 735 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 736 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 737 738 skb_push(skb, -skb_network_offset(skb)); 739 740 return esp6_output_tail(x, skb, &esp); 741 } 742 743 static inline int esp_remove_trailer(struct sk_buff *skb) 744 { 745 struct xfrm_state *x = xfrm_input_state(skb); 746 struct crypto_aead *aead = x->data; 747 int alen, hlen, elen; 748 int padlen, trimlen; 749 __wsum csumdiff; 750 u8 nexthdr[2]; 751 int ret; 752 753 alen = crypto_aead_authsize(aead); 754 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 755 elen = skb->len - hlen; 756 757 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2); 758 BUG_ON(ret); 759 760 ret = -EINVAL; 761 padlen = nexthdr[0]; 762 if (padlen + 2 + alen >= elen) { 763 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 764 padlen + 2, elen - alen); 765 goto out; 766 } 767 768 trimlen = alen + padlen + 2; 769 if (skb->ip_summed == CHECKSUM_COMPLETE) { 770 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 771 skb->csum = csum_block_sub(skb->csum, csumdiff, 772 skb->len - trimlen); 773 } 774 ret = pskb_trim(skb, skb->len - trimlen); 775 if (unlikely(ret)) 776 return ret; 777 778 ret = nexthdr[1]; 779 780 out: 781 return ret; 782 } 783 784 int esp6_input_done2(struct sk_buff *skb, int err) 785 { 786 struct xfrm_state *x = xfrm_input_state(skb); 787 struct xfrm_offload *xo = xfrm_offload(skb); 788 struct crypto_aead *aead = x->data; 789 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 790 int hdr_len = skb_network_header_len(skb); 791 792 if (!xo || !(xo->flags & CRYPTO_DONE)) 793 kfree(ESP_SKB_CB(skb)->tmp); 794 795 if (unlikely(err)) 796 goto out; 797 798 err = esp_remove_trailer(skb); 799 if (unlikely(err < 0)) 800 goto out; 801 802 if (x->encap) { 803 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 804 int offset = skb_network_offset(skb) + sizeof(*ip6h); 805 struct xfrm_encap_tmpl *encap = x->encap; 806 u8 nexthdr = ip6h->nexthdr; 807 __be16 frag_off, source; 808 struct udphdr *uh; 809 struct tcphdr *th; 810 811 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); 812 if (offset == -1) { 813 err = -EINVAL; 814 goto out; 815 } 816 817 uh = (void *)(skb->data + offset); 818 th = (void *)(skb->data + offset); 819 hdr_len += offset; 820 821 switch (x->encap->encap_type) { 822 case TCP_ENCAP_ESPINTCP: 823 source = th->source; 824 break; 825 case UDP_ENCAP_ESPINUDP: 826 case UDP_ENCAP_ESPINUDP_NON_IKE: 827 source = uh->source; 828 break; 829 default: 830 WARN_ON_ONCE(1); 831 err = -EINVAL; 832 goto out; 833 } 834 835 /* 836 * 1) if the NAT-T peer's IP or port changed then 837 * advertise the change to the keying daemon. 838 * This is an inbound SA, so just compare 839 * SRC ports. 840 */ 841 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) || 842 source != encap->encap_sport) { 843 xfrm_address_t ipaddr; 844 845 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6)); 846 km_new_mapping(x, &ipaddr, source); 847 848 /* XXX: perhaps add an extra 849 * policy check here, to see 850 * if we should allow or 851 * reject a packet from a 852 * different source 853 * address/port. 854 */ 855 } 856 857 /* 858 * 2) ignore UDP/TCP checksums in case 859 * of NAT-T in Transport Mode, or 860 * perform other post-processing fixes 861 * as per draft-ietf-ipsec-udp-encaps-06, 862 * section 3.1.2 863 */ 864 if (x->props.mode == XFRM_MODE_TRANSPORT) 865 skb->ip_summed = CHECKSUM_UNNECESSARY; 866 } 867 868 skb_postpull_rcsum(skb, skb_network_header(skb), 869 skb_network_header_len(skb)); 870 skb_pull_rcsum(skb, hlen); 871 if (x->props.mode == XFRM_MODE_TUNNEL) 872 skb_reset_transport_header(skb); 873 else 874 skb_set_transport_header(skb, -hdr_len); 875 876 /* RFC4303: Drop dummy packets without any error */ 877 if (err == IPPROTO_NONE) 878 err = -EINVAL; 879 880 out: 881 return err; 882 } 883 EXPORT_SYMBOL_GPL(esp6_input_done2); 884 885 static void esp_input_done(void *data, int err) 886 { 887 struct sk_buff *skb = data; 888 889 xfrm_input_resume(skb, esp6_input_done2(skb, err)); 890 } 891 892 static void esp_input_restore_header(struct sk_buff *skb) 893 { 894 esp_restore_header(skb, 0); 895 __skb_pull(skb, 4); 896 } 897 898 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 899 { 900 struct xfrm_state *x = xfrm_input_state(skb); 901 902 /* For ESN we move the header forward by 4 bytes to 903 * accommodate the high bits. We will move it back after 904 * decryption. 905 */ 906 if ((x->props.flags & XFRM_STATE_ESN)) { 907 struct ip_esp_hdr *esph = skb_push(skb, 4); 908 909 *seqhi = esph->spi; 910 esph->spi = esph->seq_no; 911 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 912 } 913 } 914 915 static void esp_input_done_esn(void *data, int err) 916 { 917 struct sk_buff *skb = data; 918 919 esp_input_restore_header(skb); 920 esp_input_done(data, err); 921 } 922 923 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) 924 { 925 struct crypto_aead *aead = x->data; 926 struct aead_request *req; 927 struct sk_buff *trailer; 928 int ivlen = crypto_aead_ivsize(aead); 929 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 930 int nfrags; 931 int assoclen; 932 int seqhilen; 933 int ret = 0; 934 void *tmp; 935 __be32 *seqhi; 936 u8 *iv; 937 struct scatterlist *sg; 938 939 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) { 940 ret = -EINVAL; 941 goto out; 942 } 943 944 if (elen <= 0) { 945 ret = -EINVAL; 946 goto out; 947 } 948 949 assoclen = sizeof(struct ip_esp_hdr); 950 seqhilen = 0; 951 952 if (x->props.flags & XFRM_STATE_ESN) { 953 seqhilen += sizeof(__be32); 954 assoclen += seqhilen; 955 } 956 957 if (!skb_cloned(skb)) { 958 if (!skb_is_nonlinear(skb)) { 959 nfrags = 1; 960 961 goto skip_cow; 962 } else if (!skb_has_frag_list(skb)) { 963 nfrags = skb_shinfo(skb)->nr_frags; 964 nfrags++; 965 966 goto skip_cow; 967 } 968 } 969 970 nfrags = skb_cow_data(skb, 0, &trailer); 971 if (nfrags < 0) { 972 ret = -EINVAL; 973 goto out; 974 } 975 976 skip_cow: 977 ret = -ENOMEM; 978 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 979 if (!tmp) 980 goto out; 981 982 ESP_SKB_CB(skb)->tmp = tmp; 983 seqhi = esp_tmp_extra(tmp); 984 iv = esp_tmp_iv(aead, tmp, seqhilen); 985 req = esp_tmp_req(aead, iv); 986 sg = esp_req_sg(aead, req); 987 988 esp_input_set_header(skb, seqhi); 989 990 sg_init_table(sg, nfrags); 991 ret = skb_to_sgvec(skb, sg, 0, skb->len); 992 if (unlikely(ret < 0)) { 993 kfree(tmp); 994 goto out; 995 } 996 997 skb->ip_summed = CHECKSUM_NONE; 998 999 if ((x->props.flags & XFRM_STATE_ESN)) 1000 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 1001 else 1002 aead_request_set_callback(req, 0, esp_input_done, skb); 1003 1004 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 1005 aead_request_set_ad(req, assoclen); 1006 1007 ret = crypto_aead_decrypt(req); 1008 if (ret == -EINPROGRESS) 1009 goto out; 1010 1011 if ((x->props.flags & XFRM_STATE_ESN)) 1012 esp_input_restore_header(skb); 1013 1014 ret = esp6_input_done2(skb, ret); 1015 1016 out: 1017 return ret; 1018 } 1019 1020 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 1021 u8 type, u8 code, int offset, __be32 info) 1022 { 1023 struct net *net = dev_net(skb->dev); 1024 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 1025 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset); 1026 struct xfrm_state *x; 1027 1028 if (type != ICMPV6_PKT_TOOBIG && 1029 type != NDISC_REDIRECT) 1030 return 0; 1031 1032 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 1033 esph->spi, IPPROTO_ESP, AF_INET6); 1034 if (!x) 1035 return 0; 1036 1037 if (type == NDISC_REDIRECT) 1038 ip6_redirect(skb, net, skb->dev->ifindex, 0, 1039 sock_net_uid(net, NULL)); 1040 else 1041 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 1042 xfrm_state_put(x); 1043 1044 return 0; 1045 } 1046 1047 static void esp6_destroy(struct xfrm_state *x) 1048 { 1049 struct crypto_aead *aead = x->data; 1050 1051 if (!aead) 1052 return; 1053 1054 crypto_free_aead(aead); 1055 } 1056 1057 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 1058 { 1059 char aead_name[CRYPTO_MAX_ALG_NAME]; 1060 struct crypto_aead *aead; 1061 int err; 1062 1063 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1064 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 1065 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1066 return -ENAMETOOLONG; 1067 } 1068 1069 aead = crypto_alloc_aead(aead_name, 0, 0); 1070 err = PTR_ERR(aead); 1071 if (IS_ERR(aead)) 1072 goto error; 1073 1074 x->data = aead; 1075 1076 err = crypto_aead_setkey(aead, x->aead->alg_key, 1077 (x->aead->alg_key_len + 7) / 8); 1078 if (err) 1079 goto error; 1080 1081 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1082 if (err) 1083 goto error; 1084 1085 return 0; 1086 1087 error: 1088 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1089 return err; 1090 } 1091 1092 static int esp_init_authenc(struct xfrm_state *x, 1093 struct netlink_ext_ack *extack) 1094 { 1095 struct crypto_aead *aead; 1096 struct crypto_authenc_key_param *param; 1097 struct rtattr *rta; 1098 char *key; 1099 char *p; 1100 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1101 unsigned int keylen; 1102 int err; 1103 1104 err = -ENAMETOOLONG; 1105 1106 if ((x->props.flags & XFRM_STATE_ESN)) { 1107 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1108 "%s%sauthencesn(%s,%s)%s", 1109 x->geniv ?: "", x->geniv ? "(" : "", 1110 x->aalg ? x->aalg->alg_name : "digest_null", 1111 x->ealg->alg_name, 1112 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1113 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1114 goto error; 1115 } 1116 } else { 1117 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1118 "%s%sauthenc(%s,%s)%s", 1119 x->geniv ?: "", x->geniv ? "(" : "", 1120 x->aalg ? x->aalg->alg_name : "digest_null", 1121 x->ealg->alg_name, 1122 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1123 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1124 goto error; 1125 } 1126 } 1127 1128 aead = crypto_alloc_aead(authenc_name, 0, 0); 1129 err = PTR_ERR(aead); 1130 if (IS_ERR(aead)) { 1131 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1132 goto error; 1133 } 1134 1135 x->data = aead; 1136 1137 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1138 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1139 err = -ENOMEM; 1140 key = kmalloc(keylen, GFP_KERNEL); 1141 if (!key) 1142 goto error; 1143 1144 p = key; 1145 rta = (void *)p; 1146 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1147 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1148 param = RTA_DATA(rta); 1149 p += RTA_SPACE(sizeof(*param)); 1150 1151 if (x->aalg) { 1152 struct xfrm_algo_desc *aalg_desc; 1153 1154 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1155 p += (x->aalg->alg_key_len + 7) / 8; 1156 1157 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1158 BUG_ON(!aalg_desc); 1159 1160 err = -EINVAL; 1161 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1162 crypto_aead_authsize(aead)) { 1163 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1164 goto free_key; 1165 } 1166 1167 err = crypto_aead_setauthsize( 1168 aead, x->aalg->alg_trunc_len / 8); 1169 if (err) { 1170 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1171 goto free_key; 1172 } 1173 } 1174 1175 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1176 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1177 1178 err = crypto_aead_setkey(aead, key, keylen); 1179 1180 free_key: 1181 kfree(key); 1182 1183 error: 1184 return err; 1185 } 1186 1187 static int esp6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1188 { 1189 struct crypto_aead *aead; 1190 u32 align; 1191 int err; 1192 1193 x->data = NULL; 1194 1195 if (x->aead) { 1196 err = esp_init_aead(x, extack); 1197 } else if (x->ealg) { 1198 err = esp_init_authenc(x, extack); 1199 } else { 1200 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1201 err = -EINVAL; 1202 } 1203 1204 if (err) 1205 goto error; 1206 1207 aead = x->data; 1208 1209 x->props.header_len = sizeof(struct ip_esp_hdr) + 1210 crypto_aead_ivsize(aead); 1211 switch (x->props.mode) { 1212 case XFRM_MODE_BEET: 1213 if (x->sel.family != AF_INET6) 1214 x->props.header_len += IPV4_BEET_PHMAXLEN + 1215 (sizeof(struct ipv6hdr) - sizeof(struct iphdr)); 1216 break; 1217 default: 1218 case XFRM_MODE_TRANSPORT: 1219 break; 1220 case XFRM_MODE_TUNNEL: 1221 x->props.header_len += sizeof(struct ipv6hdr); 1222 break; 1223 } 1224 1225 if (x->encap) { 1226 struct xfrm_encap_tmpl *encap = x->encap; 1227 1228 switch (encap->encap_type) { 1229 default: 1230 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1231 err = -EINVAL; 1232 goto error; 1233 case UDP_ENCAP_ESPINUDP: 1234 x->props.header_len += sizeof(struct udphdr); 1235 break; 1236 case UDP_ENCAP_ESPINUDP_NON_IKE: 1237 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 1238 break; 1239 #ifdef CONFIG_INET6_ESPINTCP 1240 case TCP_ENCAP_ESPINTCP: 1241 /* only the length field, TCP encap is done by 1242 * the socket 1243 */ 1244 x->props.header_len += 2; 1245 break; 1246 #endif 1247 } 1248 } 1249 1250 align = ALIGN(crypto_aead_blocksize(aead), 4); 1251 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1252 1253 error: 1254 return err; 1255 } 1256 1257 static int esp6_rcv_cb(struct sk_buff *skb, int err) 1258 { 1259 return 0; 1260 } 1261 1262 static const struct xfrm_type esp6_type = { 1263 .owner = THIS_MODULE, 1264 .proto = IPPROTO_ESP, 1265 .flags = XFRM_TYPE_REPLAY_PROT, 1266 .init_state = esp6_init_state, 1267 .destructor = esp6_destroy, 1268 .input = esp6_input, 1269 .output = esp6_output, 1270 }; 1271 1272 static struct xfrm6_protocol esp6_protocol = { 1273 .handler = xfrm6_rcv, 1274 .input_handler = xfrm_input, 1275 .cb_handler = esp6_rcv_cb, 1276 .err_handler = esp6_err, 1277 .priority = 0, 1278 }; 1279 1280 static int __init esp6_init(void) 1281 { 1282 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { 1283 pr_info("%s: can't add xfrm type\n", __func__); 1284 return -EAGAIN; 1285 } 1286 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) { 1287 pr_info("%s: can't add protocol\n", __func__); 1288 xfrm_unregister_type(&esp6_type, AF_INET6); 1289 return -EAGAIN; 1290 } 1291 1292 return 0; 1293 } 1294 1295 static void __exit esp6_fini(void) 1296 { 1297 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0) 1298 pr_info("%s: can't remove protocol\n", __func__); 1299 xfrm_unregister_type(&esp6_type, AF_INET6); 1300 } 1301 1302 module_init(esp6_init); 1303 module_exit(esp6_fini); 1304 1305 MODULE_DESCRIPTION("IPv6 ESP transformation helpers"); 1306 MODULE_LICENSE("GPL"); 1307 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP); 1308