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