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 WARN_ON(1); 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, skb); 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 unsigned int len; 387 388 len = skb->len + esp->tailen - skb_transport_offset(skb); 389 if (len > U16_MAX) 390 return ERR_PTR(-EMSGSIZE); 391 392 uh = (struct udphdr *)esp->esph; 393 uh->source = sport; 394 uh->dest = dport; 395 uh->len = htons(len); 396 uh->check = 0; 397 398 *skb_mac_header(skb) = IPPROTO_UDP; 399 400 return (struct ip_esp_hdr *)(uh + 1); 401 } 402 403 #ifdef CONFIG_INET6_ESPINTCP 404 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x, 405 struct sk_buff *skb, 406 struct esp_info *esp) 407 { 408 __be16 *lenp = (void *)esp->esph; 409 struct ip_esp_hdr *esph; 410 unsigned int len; 411 struct sock *sk; 412 413 len = skb->len + esp->tailen - skb_transport_offset(skb); 414 if (len > IP_MAX_MTU) 415 return ERR_PTR(-EMSGSIZE); 416 417 rcu_read_lock(); 418 sk = esp6_find_tcp_sk(x); 419 rcu_read_unlock(); 420 421 if (IS_ERR(sk)) 422 return ERR_CAST(sk); 423 424 *lenp = htons(len); 425 esph = (struct ip_esp_hdr *)(lenp + 1); 426 427 return esph; 428 } 429 #else 430 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x, 431 struct sk_buff *skb, 432 struct esp_info *esp) 433 { 434 return ERR_PTR(-EOPNOTSUPP); 435 } 436 #endif 437 438 static int esp6_output_encap(struct xfrm_state *x, struct sk_buff *skb, 439 struct esp_info *esp) 440 { 441 struct xfrm_encap_tmpl *encap = x->encap; 442 struct ip_esp_hdr *esph; 443 __be16 sport, dport; 444 int encap_type; 445 446 spin_lock_bh(&x->lock); 447 sport = encap->encap_sport; 448 dport = encap->encap_dport; 449 encap_type = encap->encap_type; 450 spin_unlock_bh(&x->lock); 451 452 switch (encap_type) { 453 default: 454 case UDP_ENCAP_ESPINUDP: 455 esph = esp6_output_udp_encap(skb, encap_type, esp, sport, dport); 456 break; 457 case TCP_ENCAP_ESPINTCP: 458 esph = esp6_output_tcp_encap(x, skb, esp); 459 break; 460 } 461 462 if (IS_ERR(esph)) 463 return PTR_ERR(esph); 464 465 esp->esph = esph; 466 467 return 0; 468 } 469 470 int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 471 { 472 u8 *tail; 473 int nfrags; 474 int esph_offset; 475 struct page *page; 476 struct sk_buff *trailer; 477 int tailen = esp->tailen; 478 479 if (x->encap) { 480 int err = esp6_output_encap(x, skb, esp); 481 482 if (err < 0) 483 return err; 484 } 485 486 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE || 487 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE) 488 goto cow; 489 490 if (!skb_cloned(skb)) { 491 if (tailen <= skb_tailroom(skb)) { 492 nfrags = 1; 493 trailer = skb; 494 tail = skb_tail_pointer(trailer); 495 496 goto skip_cow; 497 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 498 && !skb_has_frag_list(skb)) { 499 int allocsize; 500 struct sock *sk = skb->sk; 501 struct page_frag *pfrag = &x->xfrag; 502 503 esp->inplace = false; 504 505 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 506 507 spin_lock_bh(&x->lock); 508 509 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 510 spin_unlock_bh(&x->lock); 511 goto cow; 512 } 513 514 page = pfrag->page; 515 get_page(page); 516 517 tail = page_address(page) + pfrag->offset; 518 519 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 520 521 nfrags = skb_shinfo(skb)->nr_frags; 522 523 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 524 tailen); 525 skb_shinfo(skb)->nr_frags = ++nfrags; 526 527 pfrag->offset = pfrag->offset + allocsize; 528 529 spin_unlock_bh(&x->lock); 530 531 nfrags++; 532 533 skb->len += tailen; 534 skb->data_len += tailen; 535 skb->truesize += tailen; 536 if (sk && sk_fullsock(sk)) 537 refcount_add(tailen, &sk->sk_wmem_alloc); 538 539 goto out; 540 } 541 } 542 543 cow: 544 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 545 546 nfrags = skb_cow_data(skb, tailen, &trailer); 547 if (nfrags < 0) 548 goto out; 549 tail = skb_tail_pointer(trailer); 550 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 551 552 skip_cow: 553 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 554 pskb_put(skb, trailer, tailen); 555 556 out: 557 return nfrags; 558 } 559 EXPORT_SYMBOL_GPL(esp6_output_head); 560 561 int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 562 { 563 u8 *iv; 564 int alen; 565 void *tmp; 566 int ivlen; 567 int assoclen; 568 int extralen; 569 struct page *page; 570 struct ip_esp_hdr *esph; 571 struct aead_request *req; 572 struct crypto_aead *aead; 573 struct scatterlist *sg, *dsg; 574 struct esp_output_extra *extra; 575 int err = -ENOMEM; 576 577 assoclen = sizeof(struct ip_esp_hdr); 578 extralen = 0; 579 580 if (x->props.flags & XFRM_STATE_ESN) { 581 extralen += sizeof(*extra); 582 assoclen += sizeof(__be32); 583 } 584 585 aead = x->data; 586 alen = crypto_aead_authsize(aead); 587 ivlen = crypto_aead_ivsize(aead); 588 589 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 590 if (!tmp) 591 goto error; 592 593 extra = esp_tmp_extra(tmp); 594 iv = esp_tmp_iv(aead, tmp, extralen); 595 req = esp_tmp_req(aead, iv); 596 sg = esp_req_sg(aead, req); 597 598 if (esp->inplace) 599 dsg = sg; 600 else 601 dsg = &sg[esp->nfrags]; 602 603 esph = esp_output_set_esn(skb, x, esp->esph, extra); 604 esp->esph = esph; 605 606 sg_init_table(sg, esp->nfrags); 607 err = skb_to_sgvec(skb, sg, 608 (unsigned char *)esph - skb->data, 609 assoclen + ivlen + esp->clen + alen); 610 if (unlikely(err < 0)) 611 goto error_free; 612 613 if (!esp->inplace) { 614 int allocsize; 615 struct page_frag *pfrag = &x->xfrag; 616 617 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 618 619 spin_lock_bh(&x->lock); 620 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 621 spin_unlock_bh(&x->lock); 622 goto error_free; 623 } 624 625 skb_shinfo(skb)->nr_frags = 1; 626 627 page = pfrag->page; 628 get_page(page); 629 /* replace page frags in skb with new page */ 630 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 631 pfrag->offset = pfrag->offset + allocsize; 632 spin_unlock_bh(&x->lock); 633 634 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 635 err = skb_to_sgvec(skb, dsg, 636 (unsigned char *)esph - skb->data, 637 assoclen + ivlen + esp->clen + alen); 638 if (unlikely(err < 0)) 639 goto error_free; 640 } 641 642 if ((x->props.flags & XFRM_STATE_ESN)) 643 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 644 else 645 aead_request_set_callback(req, 0, esp_output_done, skb); 646 647 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 648 aead_request_set_ad(req, assoclen); 649 650 memset(iv, 0, ivlen); 651 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 652 min(ivlen, 8)); 653 654 ESP_SKB_CB(skb)->tmp = tmp; 655 err = crypto_aead_encrypt(req); 656 657 switch (err) { 658 case -EINPROGRESS: 659 goto error; 660 661 case -ENOSPC: 662 err = NET_XMIT_DROP; 663 break; 664 665 case 0: 666 if ((x->props.flags & XFRM_STATE_ESN)) 667 esp_output_restore_header(skb); 668 esp_output_encap_csum(skb); 669 } 670 671 if (sg != dsg) 672 esp_ssg_unref(x, tmp, skb); 673 674 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 675 err = esp_output_tail_tcp(x, skb); 676 677 error_free: 678 kfree(tmp); 679 error: 680 return err; 681 } 682 EXPORT_SYMBOL_GPL(esp6_output_tail); 683 684 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) 685 { 686 int alen; 687 int blksize; 688 struct ip_esp_hdr *esph; 689 struct crypto_aead *aead; 690 struct esp_info esp; 691 692 esp.inplace = true; 693 694 esp.proto = *skb_mac_header(skb); 695 *skb_mac_header(skb) = IPPROTO_ESP; 696 697 /* skb is pure payload to encrypt */ 698 699 aead = x->data; 700 alen = crypto_aead_authsize(aead); 701 702 esp.tfclen = 0; 703 if (x->tfcpad) { 704 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 705 u32 padto; 706 707 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 708 if (skb->len < padto) 709 esp.tfclen = padto - skb->len; 710 } 711 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 712 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 713 esp.plen = esp.clen - skb->len - esp.tfclen; 714 esp.tailen = esp.tfclen + esp.plen + alen; 715 716 esp.esph = ip_esp_hdr(skb); 717 718 esp.nfrags = esp6_output_head(x, skb, &esp); 719 if (esp.nfrags < 0) 720 return esp.nfrags; 721 722 esph = esp.esph; 723 esph->spi = x->id.spi; 724 725 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 726 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 727 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 728 729 skb_push(skb, -skb_network_offset(skb)); 730 731 return esp6_output_tail(x, skb, &esp); 732 } 733 734 static inline int esp_remove_trailer(struct sk_buff *skb) 735 { 736 struct xfrm_state *x = xfrm_input_state(skb); 737 struct crypto_aead *aead = x->data; 738 int alen, hlen, elen; 739 int padlen, trimlen; 740 __wsum csumdiff; 741 u8 nexthdr[2]; 742 int ret; 743 744 alen = crypto_aead_authsize(aead); 745 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 746 elen = skb->len - hlen; 747 748 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2); 749 BUG_ON(ret); 750 751 ret = -EINVAL; 752 padlen = nexthdr[0]; 753 if (padlen + 2 + alen >= elen) { 754 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 755 padlen + 2, elen - alen); 756 goto out; 757 } 758 759 trimlen = alen + padlen + 2; 760 if (skb->ip_summed == CHECKSUM_COMPLETE) { 761 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 762 skb->csum = csum_block_sub(skb->csum, csumdiff, 763 skb->len - trimlen); 764 } 765 ret = pskb_trim(skb, skb->len - trimlen); 766 if (unlikely(ret)) 767 return ret; 768 769 ret = nexthdr[1]; 770 771 out: 772 return ret; 773 } 774 775 int esp6_input_done2(struct sk_buff *skb, int err) 776 { 777 struct xfrm_state *x = xfrm_input_state(skb); 778 struct xfrm_offload *xo = xfrm_offload(skb); 779 struct crypto_aead *aead = x->data; 780 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 781 int hdr_len = skb_network_header_len(skb); 782 783 if (!xo || !(xo->flags & CRYPTO_DONE)) 784 kfree(ESP_SKB_CB(skb)->tmp); 785 786 if (unlikely(err)) 787 goto out; 788 789 err = esp_remove_trailer(skb); 790 if (unlikely(err < 0)) 791 goto out; 792 793 if (x->encap) { 794 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 795 int offset = skb_network_offset(skb) + sizeof(*ip6h); 796 struct xfrm_encap_tmpl *encap = x->encap; 797 u8 nexthdr = ip6h->nexthdr; 798 __be16 frag_off, source; 799 struct udphdr *uh; 800 struct tcphdr *th; 801 802 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); 803 if (offset == -1) { 804 err = -EINVAL; 805 goto out; 806 } 807 808 uh = (void *)(skb->data + offset); 809 th = (void *)(skb->data + offset); 810 hdr_len += offset; 811 812 switch (x->encap->encap_type) { 813 case TCP_ENCAP_ESPINTCP: 814 source = th->source; 815 break; 816 case UDP_ENCAP_ESPINUDP: 817 source = uh->source; 818 break; 819 default: 820 WARN_ON_ONCE(1); 821 err = -EINVAL; 822 goto out; 823 } 824 825 /* 826 * 1) if the NAT-T peer's IP or port changed then 827 * advertise the change to the keying daemon. 828 * This is an inbound SA, so just compare 829 * SRC ports. 830 */ 831 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) || 832 source != encap->encap_sport) { 833 xfrm_address_t ipaddr; 834 835 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6)); 836 km_new_mapping(x, &ipaddr, source); 837 838 /* XXX: perhaps add an extra 839 * policy check here, to see 840 * if we should allow or 841 * reject a packet from a 842 * different source 843 * address/port. 844 */ 845 } 846 847 /* 848 * 2) ignore UDP/TCP checksums in case 849 * of NAT-T in Transport Mode, or 850 * perform other post-processing fixes 851 * as per draft-ietf-ipsec-udp-encaps-06, 852 * section 3.1.2 853 */ 854 if (x->props.mode == XFRM_MODE_TRANSPORT) 855 skb->ip_summed = CHECKSUM_UNNECESSARY; 856 } 857 858 skb_postpull_rcsum(skb, skb_network_header(skb), 859 skb_network_header_len(skb)); 860 skb_pull_rcsum(skb, hlen); 861 if (x->props.mode == XFRM_MODE_TUNNEL) 862 skb_reset_transport_header(skb); 863 else 864 skb_set_transport_header(skb, -hdr_len); 865 866 /* RFC4303: Drop dummy packets without any error */ 867 if (err == IPPROTO_NONE) 868 err = -EINVAL; 869 870 out: 871 return err; 872 } 873 EXPORT_SYMBOL_GPL(esp6_input_done2); 874 875 static void esp_input_done(void *data, int err) 876 { 877 struct sk_buff *skb = data; 878 879 xfrm_input_resume(skb, esp6_input_done2(skb, err)); 880 } 881 882 static void esp_input_restore_header(struct sk_buff *skb) 883 { 884 esp_restore_header(skb, 0); 885 __skb_pull(skb, 4); 886 } 887 888 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 889 { 890 struct xfrm_state *x = xfrm_input_state(skb); 891 892 /* For ESN we move the header forward by 4 bytes to 893 * accommodate the high bits. We will move it back after 894 * decryption. 895 */ 896 if ((x->props.flags & XFRM_STATE_ESN)) { 897 struct ip_esp_hdr *esph = skb_push(skb, 4); 898 899 *seqhi = esph->spi; 900 esph->spi = esph->seq_no; 901 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 902 } 903 } 904 905 static void esp_input_done_esn(void *data, int err) 906 { 907 struct sk_buff *skb = data; 908 909 esp_input_restore_header(skb); 910 esp_input_done(data, err); 911 } 912 913 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) 914 { 915 struct crypto_aead *aead = x->data; 916 struct aead_request *req; 917 struct sk_buff *trailer; 918 int ivlen = crypto_aead_ivsize(aead); 919 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 920 int nfrags; 921 int assoclen; 922 int seqhilen; 923 int ret = 0; 924 void *tmp; 925 __be32 *seqhi; 926 u8 *iv; 927 struct scatterlist *sg; 928 929 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) { 930 ret = -EINVAL; 931 goto out; 932 } 933 934 if (elen <= 0) { 935 ret = -EINVAL; 936 goto out; 937 } 938 939 assoclen = sizeof(struct ip_esp_hdr); 940 seqhilen = 0; 941 942 if (x->props.flags & XFRM_STATE_ESN) { 943 seqhilen += sizeof(__be32); 944 assoclen += seqhilen; 945 } 946 947 if (!skb_cloned(skb)) { 948 if (!skb_is_nonlinear(skb)) { 949 nfrags = 1; 950 951 goto skip_cow; 952 } else if (!skb_has_frag_list(skb)) { 953 nfrags = skb_shinfo(skb)->nr_frags; 954 nfrags++; 955 956 goto skip_cow; 957 } 958 } 959 960 nfrags = skb_cow_data(skb, 0, &trailer); 961 if (nfrags < 0) { 962 ret = -EINVAL; 963 goto out; 964 } 965 966 skip_cow: 967 ret = -ENOMEM; 968 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 969 if (!tmp) 970 goto out; 971 972 ESP_SKB_CB(skb)->tmp = tmp; 973 seqhi = esp_tmp_extra(tmp); 974 iv = esp_tmp_iv(aead, tmp, seqhilen); 975 req = esp_tmp_req(aead, iv); 976 sg = esp_req_sg(aead, req); 977 978 esp_input_set_header(skb, seqhi); 979 980 sg_init_table(sg, nfrags); 981 ret = skb_to_sgvec(skb, sg, 0, skb->len); 982 if (unlikely(ret < 0)) { 983 kfree(tmp); 984 goto out; 985 } 986 987 skb->ip_summed = CHECKSUM_NONE; 988 989 if ((x->props.flags & XFRM_STATE_ESN)) 990 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 991 else 992 aead_request_set_callback(req, 0, esp_input_done, skb); 993 994 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 995 aead_request_set_ad(req, assoclen); 996 997 ret = crypto_aead_decrypt(req); 998 if (ret == -EINPROGRESS) 999 goto out; 1000 1001 if ((x->props.flags & XFRM_STATE_ESN)) 1002 esp_input_restore_header(skb); 1003 1004 ret = esp6_input_done2(skb, ret); 1005 1006 out: 1007 return ret; 1008 } 1009 1010 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 1011 u8 type, u8 code, int offset, __be32 info) 1012 { 1013 struct net *net = dev_net(skb->dev); 1014 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 1015 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset); 1016 struct xfrm_state *x; 1017 1018 if (type != ICMPV6_PKT_TOOBIG && 1019 type != NDISC_REDIRECT) 1020 return 0; 1021 1022 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 1023 esph->spi, IPPROTO_ESP, AF_INET6); 1024 if (!x) 1025 return 0; 1026 1027 if (type == NDISC_REDIRECT) 1028 ip6_redirect(skb, net, skb->dev->ifindex, 0, 1029 sock_net_uid(net, NULL)); 1030 else 1031 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 1032 xfrm_state_put(x); 1033 1034 return 0; 1035 } 1036 1037 static void esp6_destroy(struct xfrm_state *x) 1038 { 1039 struct crypto_aead *aead = x->data; 1040 1041 if (!aead) 1042 return; 1043 1044 crypto_free_aead(aead); 1045 } 1046 1047 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 1048 { 1049 char aead_name[CRYPTO_MAX_ALG_NAME]; 1050 struct crypto_aead *aead; 1051 int err; 1052 1053 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1054 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 1055 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1056 return -ENAMETOOLONG; 1057 } 1058 1059 aead = crypto_alloc_aead(aead_name, 0, 0); 1060 err = PTR_ERR(aead); 1061 if (IS_ERR(aead)) 1062 goto error; 1063 1064 x->data = aead; 1065 1066 err = crypto_aead_setkey(aead, x->aead->alg_key, 1067 (x->aead->alg_key_len + 7) / 8); 1068 if (err) 1069 goto error; 1070 1071 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1072 if (err) 1073 goto error; 1074 1075 return 0; 1076 1077 error: 1078 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1079 return err; 1080 } 1081 1082 static int esp_init_authenc(struct xfrm_state *x, 1083 struct netlink_ext_ack *extack) 1084 { 1085 struct crypto_aead *aead; 1086 struct crypto_authenc_key_param *param; 1087 struct rtattr *rta; 1088 char *key; 1089 char *p; 1090 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1091 unsigned int keylen; 1092 int err; 1093 1094 err = -ENAMETOOLONG; 1095 1096 if ((x->props.flags & XFRM_STATE_ESN)) { 1097 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1098 "%s%sauthencesn(%s,%s)%s", 1099 x->geniv ?: "", x->geniv ? "(" : "", 1100 x->aalg ? x->aalg->alg_name : "digest_null", 1101 x->ealg->alg_name, 1102 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1103 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1104 goto error; 1105 } 1106 } else { 1107 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1108 "%s%sauthenc(%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 } 1117 1118 aead = crypto_alloc_aead(authenc_name, 0, 0); 1119 err = PTR_ERR(aead); 1120 if (IS_ERR(aead)) { 1121 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1122 goto error; 1123 } 1124 1125 x->data = aead; 1126 1127 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1128 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1129 err = -ENOMEM; 1130 key = kmalloc(keylen, GFP_KERNEL); 1131 if (!key) 1132 goto error; 1133 1134 p = key; 1135 rta = (void *)p; 1136 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1137 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1138 param = RTA_DATA(rta); 1139 p += RTA_SPACE(sizeof(*param)); 1140 1141 if (x->aalg) { 1142 struct xfrm_algo_desc *aalg_desc; 1143 1144 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1145 p += (x->aalg->alg_key_len + 7) / 8; 1146 1147 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1148 BUG_ON(!aalg_desc); 1149 1150 err = -EINVAL; 1151 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1152 crypto_aead_authsize(aead)) { 1153 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1154 goto free_key; 1155 } 1156 1157 err = crypto_aead_setauthsize( 1158 aead, x->aalg->alg_trunc_len / 8); 1159 if (err) { 1160 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1161 goto free_key; 1162 } 1163 } 1164 1165 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1166 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1167 1168 err = crypto_aead_setkey(aead, key, keylen); 1169 1170 free_key: 1171 kfree(key); 1172 1173 error: 1174 return err; 1175 } 1176 1177 static int esp6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1178 { 1179 struct crypto_aead *aead; 1180 u32 align; 1181 int err; 1182 1183 x->data = NULL; 1184 1185 if (x->aead) { 1186 err = esp_init_aead(x, extack); 1187 } else if (x->ealg) { 1188 err = esp_init_authenc(x, extack); 1189 } else { 1190 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1191 err = -EINVAL; 1192 } 1193 1194 if (err) 1195 goto error; 1196 1197 aead = x->data; 1198 1199 x->props.header_len = sizeof(struct ip_esp_hdr) + 1200 crypto_aead_ivsize(aead); 1201 switch (x->props.mode) { 1202 case XFRM_MODE_BEET: 1203 if (x->sel.family != AF_INET6) 1204 x->props.header_len += IPV4_BEET_PHMAXLEN + 1205 (sizeof(struct ipv6hdr) - sizeof(struct iphdr)); 1206 break; 1207 default: 1208 case XFRM_MODE_TRANSPORT: 1209 break; 1210 case XFRM_MODE_TUNNEL: 1211 x->props.header_len += sizeof(struct ipv6hdr); 1212 break; 1213 } 1214 1215 if (x->encap) { 1216 struct xfrm_encap_tmpl *encap = x->encap; 1217 1218 switch (encap->encap_type) { 1219 default: 1220 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1221 err = -EINVAL; 1222 goto error; 1223 case UDP_ENCAP_ESPINUDP: 1224 x->props.header_len += sizeof(struct udphdr); 1225 break; 1226 #ifdef CONFIG_INET6_ESPINTCP 1227 case TCP_ENCAP_ESPINTCP: 1228 /* only the length field, TCP encap is done by 1229 * the socket 1230 */ 1231 x->props.header_len += 2; 1232 break; 1233 #endif 1234 } 1235 } 1236 1237 align = ALIGN(crypto_aead_blocksize(aead), 4); 1238 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1239 1240 error: 1241 return err; 1242 } 1243 1244 static int esp6_rcv_cb(struct sk_buff *skb, int err) 1245 { 1246 return 0; 1247 } 1248 1249 static const struct xfrm_type esp6_type = { 1250 .owner = THIS_MODULE, 1251 .proto = IPPROTO_ESP, 1252 .flags = XFRM_TYPE_REPLAY_PROT, 1253 .init_state = esp6_init_state, 1254 .destructor = esp6_destroy, 1255 .input = esp6_input, 1256 .output = esp6_output, 1257 }; 1258 1259 static struct xfrm6_protocol esp6_protocol = { 1260 .handler = xfrm6_rcv, 1261 .input_handler = xfrm_input, 1262 .cb_handler = esp6_rcv_cb, 1263 .err_handler = esp6_err, 1264 .priority = 0, 1265 }; 1266 1267 static int __init esp6_init(void) 1268 { 1269 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { 1270 pr_info("%s: can't add xfrm type\n", __func__); 1271 return -EAGAIN; 1272 } 1273 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) { 1274 pr_info("%s: can't add protocol\n", __func__); 1275 xfrm_unregister_type(&esp6_type, AF_INET6); 1276 return -EAGAIN; 1277 } 1278 1279 return 0; 1280 } 1281 1282 static void __exit esp6_fini(void) 1283 { 1284 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0) 1285 pr_info("%s: can't remove protocol\n", __func__); 1286 xfrm_unregister_type(&esp6_type, AF_INET6); 1287 } 1288 1289 module_init(esp6_init); 1290 module_exit(esp6_fini); 1291 1292 MODULE_DESCRIPTION("IPv6 ESP transformation helpers"); 1293 MODULE_LICENSE("GPL"); 1294 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP); 1295