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); 815 816 if (offset < 0) { 817 err = -EINVAL; 818 goto out; 819 } 820 821 uh = (void *)(skb->data + offset); 822 th = (void *)(skb->data + offset); 823 hdr_len += offset; 824 825 switch (x->encap->encap_type) { 826 case TCP_ENCAP_ESPINTCP: 827 source = th->source; 828 break; 829 case UDP_ENCAP_ESPINUDP: 830 case UDP_ENCAP_ESPINUDP_NON_IKE: 831 source = uh->source; 832 break; 833 default: 834 WARN_ON_ONCE(1); 835 err = -EINVAL; 836 goto out; 837 } 838 839 /* 840 * 1) if the NAT-T peer's IP or port changed then 841 * advertize the change to the keying daemon. 842 * This is an inbound SA, so just compare 843 * SRC ports. 844 */ 845 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) || 846 source != encap->encap_sport) { 847 xfrm_address_t ipaddr; 848 849 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6)); 850 km_new_mapping(x, &ipaddr, source); 851 852 /* XXX: perhaps add an extra 853 * policy check here, to see 854 * if we should allow or 855 * reject a packet from a 856 * different source 857 * address/port. 858 */ 859 } 860 861 /* 862 * 2) ignore UDP/TCP checksums in case 863 * of NAT-T in Transport Mode, or 864 * perform other post-processing fixes 865 * as per draft-ietf-ipsec-udp-encaps-06, 866 * section 3.1.2 867 */ 868 if (x->props.mode == XFRM_MODE_TRANSPORT) 869 skb->ip_summed = CHECKSUM_UNNECESSARY; 870 } 871 872 skb_postpull_rcsum(skb, skb_network_header(skb), 873 skb_network_header_len(skb)); 874 skb_pull_rcsum(skb, hlen); 875 if (x->props.mode == XFRM_MODE_TUNNEL) 876 skb_reset_transport_header(skb); 877 else 878 skb_set_transport_header(skb, -hdr_len); 879 880 /* RFC4303: Drop dummy packets without any error */ 881 if (err == IPPROTO_NONE) 882 err = -EINVAL; 883 884 out: 885 return err; 886 } 887 EXPORT_SYMBOL_GPL(esp6_input_done2); 888 889 static void esp_input_done(struct crypto_async_request *base, int err) 890 { 891 struct sk_buff *skb = base->data; 892 893 xfrm_input_resume(skb, esp6_input_done2(skb, err)); 894 } 895 896 static void esp_input_restore_header(struct sk_buff *skb) 897 { 898 esp_restore_header(skb, 0); 899 __skb_pull(skb, 4); 900 } 901 902 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 903 { 904 struct xfrm_state *x = xfrm_input_state(skb); 905 906 /* For ESN we move the header forward by 4 bytes to 907 * accomodate the high bits. We will move it back after 908 * decryption. 909 */ 910 if ((x->props.flags & XFRM_STATE_ESN)) { 911 struct ip_esp_hdr *esph = skb_push(skb, 4); 912 913 *seqhi = esph->spi; 914 esph->spi = esph->seq_no; 915 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 916 } 917 } 918 919 static void esp_input_done_esn(struct crypto_async_request *base, int err) 920 { 921 struct sk_buff *skb = base->data; 922 923 esp_input_restore_header(skb); 924 esp_input_done(base, err); 925 } 926 927 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) 928 { 929 struct crypto_aead *aead = x->data; 930 struct aead_request *req; 931 struct sk_buff *trailer; 932 int ivlen = crypto_aead_ivsize(aead); 933 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 934 int nfrags; 935 int assoclen; 936 int seqhilen; 937 int ret = 0; 938 void *tmp; 939 __be32 *seqhi; 940 u8 *iv; 941 struct scatterlist *sg; 942 943 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) { 944 ret = -EINVAL; 945 goto out; 946 } 947 948 if (elen <= 0) { 949 ret = -EINVAL; 950 goto out; 951 } 952 953 assoclen = sizeof(struct ip_esp_hdr); 954 seqhilen = 0; 955 956 if (x->props.flags & XFRM_STATE_ESN) { 957 seqhilen += sizeof(__be32); 958 assoclen += seqhilen; 959 } 960 961 if (!skb_cloned(skb)) { 962 if (!skb_is_nonlinear(skb)) { 963 nfrags = 1; 964 965 goto skip_cow; 966 } else if (!skb_has_frag_list(skb)) { 967 nfrags = skb_shinfo(skb)->nr_frags; 968 nfrags++; 969 970 goto skip_cow; 971 } 972 } 973 974 nfrags = skb_cow_data(skb, 0, &trailer); 975 if (nfrags < 0) { 976 ret = -EINVAL; 977 goto out; 978 } 979 980 skip_cow: 981 ret = -ENOMEM; 982 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 983 if (!tmp) 984 goto out; 985 986 ESP_SKB_CB(skb)->tmp = tmp; 987 seqhi = esp_tmp_extra(tmp); 988 iv = esp_tmp_iv(aead, tmp, seqhilen); 989 req = esp_tmp_req(aead, iv); 990 sg = esp_req_sg(aead, req); 991 992 esp_input_set_header(skb, seqhi); 993 994 sg_init_table(sg, nfrags); 995 ret = skb_to_sgvec(skb, sg, 0, skb->len); 996 if (unlikely(ret < 0)) { 997 kfree(tmp); 998 goto out; 999 } 1000 1001 skb->ip_summed = CHECKSUM_NONE; 1002 1003 if ((x->props.flags & XFRM_STATE_ESN)) 1004 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 1005 else 1006 aead_request_set_callback(req, 0, esp_input_done, skb); 1007 1008 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 1009 aead_request_set_ad(req, assoclen); 1010 1011 ret = crypto_aead_decrypt(req); 1012 if (ret == -EINPROGRESS) 1013 goto out; 1014 1015 if ((x->props.flags & XFRM_STATE_ESN)) 1016 esp_input_restore_header(skb); 1017 1018 ret = esp6_input_done2(skb, ret); 1019 1020 out: 1021 return ret; 1022 } 1023 1024 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 1025 u8 type, u8 code, int offset, __be32 info) 1026 { 1027 struct net *net = dev_net(skb->dev); 1028 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 1029 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset); 1030 struct xfrm_state *x; 1031 1032 if (type != ICMPV6_PKT_TOOBIG && 1033 type != NDISC_REDIRECT) 1034 return 0; 1035 1036 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 1037 esph->spi, IPPROTO_ESP, AF_INET6); 1038 if (!x) 1039 return 0; 1040 1041 if (type == NDISC_REDIRECT) 1042 ip6_redirect(skb, net, skb->dev->ifindex, 0, 1043 sock_net_uid(net, NULL)); 1044 else 1045 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 1046 xfrm_state_put(x); 1047 1048 return 0; 1049 } 1050 1051 static void esp6_destroy(struct xfrm_state *x) 1052 { 1053 struct crypto_aead *aead = x->data; 1054 1055 if (!aead) 1056 return; 1057 1058 crypto_free_aead(aead); 1059 } 1060 1061 static int esp_init_aead(struct xfrm_state *x) 1062 { 1063 char aead_name[CRYPTO_MAX_ALG_NAME]; 1064 struct crypto_aead *aead; 1065 int err; 1066 1067 err = -ENAMETOOLONG; 1068 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1069 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) 1070 goto error; 1071 1072 aead = crypto_alloc_aead(aead_name, 0, 0); 1073 err = PTR_ERR(aead); 1074 if (IS_ERR(aead)) 1075 goto error; 1076 1077 x->data = aead; 1078 1079 err = crypto_aead_setkey(aead, x->aead->alg_key, 1080 (x->aead->alg_key_len + 7) / 8); 1081 if (err) 1082 goto error; 1083 1084 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1085 if (err) 1086 goto error; 1087 1088 error: 1089 return err; 1090 } 1091 1092 static int esp_init_authenc(struct xfrm_state *x) 1093 { 1094 struct crypto_aead *aead; 1095 struct crypto_authenc_key_param *param; 1096 struct rtattr *rta; 1097 char *key; 1098 char *p; 1099 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1100 unsigned int keylen; 1101 int err; 1102 1103 err = -EINVAL; 1104 if (!x->ealg) 1105 goto error; 1106 1107 err = -ENAMETOOLONG; 1108 1109 if ((x->props.flags & XFRM_STATE_ESN)) { 1110 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1111 "%s%sauthencesn(%s,%s)%s", 1112 x->geniv ?: "", x->geniv ? "(" : "", 1113 x->aalg ? x->aalg->alg_name : "digest_null", 1114 x->ealg->alg_name, 1115 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1116 goto error; 1117 } else { 1118 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1119 "%s%sauthenc(%s,%s)%s", 1120 x->geniv ?: "", x->geniv ? "(" : "", 1121 x->aalg ? x->aalg->alg_name : "digest_null", 1122 x->ealg->alg_name, 1123 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1124 goto error; 1125 } 1126 1127 aead = crypto_alloc_aead(authenc_name, 0, 0); 1128 err = PTR_ERR(aead); 1129 if (IS_ERR(aead)) 1130 goto error; 1131 1132 x->data = aead; 1133 1134 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1135 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1136 err = -ENOMEM; 1137 key = kmalloc(keylen, GFP_KERNEL); 1138 if (!key) 1139 goto error; 1140 1141 p = key; 1142 rta = (void *)p; 1143 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1144 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1145 param = RTA_DATA(rta); 1146 p += RTA_SPACE(sizeof(*param)); 1147 1148 if (x->aalg) { 1149 struct xfrm_algo_desc *aalg_desc; 1150 1151 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1152 p += (x->aalg->alg_key_len + 7) / 8; 1153 1154 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1155 BUG_ON(!aalg_desc); 1156 1157 err = -EINVAL; 1158 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1159 crypto_aead_authsize(aead)) { 1160 pr_info("ESP: %s digestsize %u != %u\n", 1161 x->aalg->alg_name, 1162 crypto_aead_authsize(aead), 1163 aalg_desc->uinfo.auth.icv_fullbits / 8); 1164 goto free_key; 1165 } 1166 1167 err = crypto_aead_setauthsize( 1168 aead, x->aalg->alg_trunc_len / 8); 1169 if (err) 1170 goto free_key; 1171 } 1172 1173 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1174 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1175 1176 err = crypto_aead_setkey(aead, key, keylen); 1177 1178 free_key: 1179 kfree(key); 1180 1181 error: 1182 return err; 1183 } 1184 1185 static int esp6_init_state(struct xfrm_state *x) 1186 { 1187 struct crypto_aead *aead; 1188 u32 align; 1189 int err; 1190 1191 x->data = NULL; 1192 1193 if (x->aead) 1194 err = esp_init_aead(x); 1195 else 1196 err = esp_init_authenc(x); 1197 1198 if (err) 1199 goto error; 1200 1201 aead = x->data; 1202 1203 x->props.header_len = sizeof(struct ip_esp_hdr) + 1204 crypto_aead_ivsize(aead); 1205 switch (x->props.mode) { 1206 case XFRM_MODE_BEET: 1207 if (x->sel.family != AF_INET6) 1208 x->props.header_len += IPV4_BEET_PHMAXLEN + 1209 (sizeof(struct ipv6hdr) - sizeof(struct iphdr)); 1210 break; 1211 default: 1212 case XFRM_MODE_TRANSPORT: 1213 break; 1214 case XFRM_MODE_TUNNEL: 1215 x->props.header_len += sizeof(struct ipv6hdr); 1216 break; 1217 } 1218 1219 if (x->encap) { 1220 struct xfrm_encap_tmpl *encap = x->encap; 1221 1222 switch (encap->encap_type) { 1223 default: 1224 err = -EINVAL; 1225 goto error; 1226 case UDP_ENCAP_ESPINUDP: 1227 x->props.header_len += sizeof(struct udphdr); 1228 break; 1229 case UDP_ENCAP_ESPINUDP_NON_IKE: 1230 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 1231 break; 1232 #ifdef CONFIG_INET6_ESPINTCP 1233 case TCP_ENCAP_ESPINTCP: 1234 /* only the length field, TCP encap is done by 1235 * the socket 1236 */ 1237 x->props.header_len += 2; 1238 break; 1239 #endif 1240 } 1241 } 1242 1243 align = ALIGN(crypto_aead_blocksize(aead), 4); 1244 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1245 1246 error: 1247 return err; 1248 } 1249 1250 static int esp6_rcv_cb(struct sk_buff *skb, int err) 1251 { 1252 return 0; 1253 } 1254 1255 static const struct xfrm_type esp6_type = { 1256 .owner = THIS_MODULE, 1257 .proto = IPPROTO_ESP, 1258 .flags = XFRM_TYPE_REPLAY_PROT, 1259 .init_state = esp6_init_state, 1260 .destructor = esp6_destroy, 1261 .input = esp6_input, 1262 .output = esp6_output, 1263 }; 1264 1265 static struct xfrm6_protocol esp6_protocol = { 1266 .handler = xfrm6_rcv, 1267 .input_handler = xfrm_input, 1268 .cb_handler = esp6_rcv_cb, 1269 .err_handler = esp6_err, 1270 .priority = 0, 1271 }; 1272 1273 static int __init esp6_init(void) 1274 { 1275 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { 1276 pr_info("%s: can't add xfrm type\n", __func__); 1277 return -EAGAIN; 1278 } 1279 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) { 1280 pr_info("%s: can't add protocol\n", __func__); 1281 xfrm_unregister_type(&esp6_type, AF_INET6); 1282 return -EAGAIN; 1283 } 1284 1285 return 0; 1286 } 1287 1288 static void __exit esp6_fini(void) 1289 { 1290 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0) 1291 pr_info("%s: can't remove protocol\n", __func__); 1292 xfrm_unregister_type(&esp6_type, AF_INET6); 1293 } 1294 1295 module_init(esp6_init); 1296 module_exit(esp6_fini); 1297 1298 MODULE_LICENSE("GPL"); 1299 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP); 1300