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 esp_output_extra *extra = esp_tmp_extra(tmp); 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(*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 put_page(sg_page(sg)); 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 esp_tcp_sk *esk; 156 __be16 sport, dport; 157 struct sock *nsk; 158 struct sock *sk; 159 160 sk = rcu_dereference(x->encap_sk); 161 if (sk && sk->sk_state == TCP_ESTABLISHED) 162 return sk; 163 164 spin_lock_bh(&x->lock); 165 sport = encap->encap_sport; 166 dport = encap->encap_dport; 167 nsk = rcu_dereference_protected(x->encap_sk, 168 lockdep_is_held(&x->lock)); 169 if (sk && sk == nsk) { 170 esk = kmalloc(sizeof(*esk), GFP_ATOMIC); 171 if (!esk) { 172 spin_unlock_bh(&x->lock); 173 return ERR_PTR(-ENOMEM); 174 } 175 RCU_INIT_POINTER(x->encap_sk, NULL); 176 esk->sk = sk; 177 call_rcu(&esk->rcu, esp_free_tcp_sk); 178 } 179 spin_unlock_bh(&x->lock); 180 181 sk = __inet6_lookup_established(xs_net(x), &tcp_hashinfo, &x->id.daddr.in6, 182 dport, &x->props.saddr.in6, ntohs(sport), 0, 0); 183 if (!sk) 184 return ERR_PTR(-ENOENT); 185 186 if (!tcp_is_ulp_esp(sk)) { 187 sock_put(sk); 188 return ERR_PTR(-EINVAL); 189 } 190 191 spin_lock_bh(&x->lock); 192 nsk = rcu_dereference_protected(x->encap_sk, 193 lockdep_is_held(&x->lock)); 194 if (encap->encap_sport != sport || 195 encap->encap_dport != dport) { 196 sock_put(sk); 197 sk = nsk ?: ERR_PTR(-EREMCHG); 198 } else if (sk == nsk) { 199 sock_put(sk); 200 } else { 201 rcu_assign_pointer(x->encap_sk, sk); 202 } 203 spin_unlock_bh(&x->lock); 204 205 return sk; 206 } 207 208 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) 209 { 210 struct sock *sk; 211 int err; 212 213 rcu_read_lock(); 214 215 sk = esp6_find_tcp_sk(x); 216 err = PTR_ERR_OR_ZERO(sk); 217 if (err) 218 goto out; 219 220 bh_lock_sock(sk); 221 if (sock_owned_by_user(sk)) 222 err = espintcp_queue_out(sk, skb); 223 else 224 err = espintcp_push_skb(sk, skb); 225 bh_unlock_sock(sk); 226 227 out: 228 rcu_read_unlock(); 229 return err; 230 } 231 232 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk, 233 struct sk_buff *skb) 234 { 235 struct dst_entry *dst = skb_dst(skb); 236 struct xfrm_state *x = dst->xfrm; 237 238 return esp_output_tcp_finish(x, skb); 239 } 240 241 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 242 { 243 int err; 244 245 local_bh_disable(); 246 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb); 247 local_bh_enable(); 248 249 /* EINPROGRESS just happens to do the right thing. It 250 * actually means that the skb has been consumed and 251 * isn't coming back. 252 */ 253 return err ?: -EINPROGRESS; 254 } 255 #else 256 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 257 { 258 kfree_skb(skb); 259 260 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(struct crypto_async_request *base, int err) 282 { 283 struct sk_buff *skb = base->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); 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, 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 * accomodate 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(struct crypto_async_request *base, int err) 372 { 373 struct sk_buff *skb = base->data; 374 375 esp_output_restore_header(skb); 376 esp_output_done(base, 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 __be32 *udpdata32; 387 unsigned int len; 388 389 len = skb->len + esp->tailen - skb_transport_offset(skb); 390 if (len > U16_MAX) 391 return ERR_PTR(-EMSGSIZE); 392 393 uh = (struct udphdr *)esp->esph; 394 uh->source = sport; 395 uh->dest = dport; 396 uh->len = htons(len); 397 uh->check = 0; 398 399 *skb_mac_header(skb) = IPPROTO_UDP; 400 401 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) { 402 udpdata32 = (__be32 *)(uh + 1); 403 udpdata32[0] = udpdata32[1] = 0; 404 return (struct ip_esp_hdr *)(udpdata32 + 2); 405 } 406 407 return (struct ip_esp_hdr *)(uh + 1); 408 } 409 410 #ifdef CONFIG_INET6_ESPINTCP 411 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x, 412 struct sk_buff *skb, 413 struct esp_info *esp) 414 { 415 __be16 *lenp = (void *)esp->esph; 416 struct ip_esp_hdr *esph; 417 unsigned int len; 418 struct sock *sk; 419 420 len = skb->len + esp->tailen - skb_transport_offset(skb); 421 if (len > IP_MAX_MTU) 422 return ERR_PTR(-EMSGSIZE); 423 424 rcu_read_lock(); 425 sk = esp6_find_tcp_sk(x); 426 rcu_read_unlock(); 427 428 if (IS_ERR(sk)) 429 return ERR_CAST(sk); 430 431 *lenp = htons(len); 432 esph = (struct ip_esp_hdr *)(lenp + 1); 433 434 return esph; 435 } 436 #else 437 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x, 438 struct sk_buff *skb, 439 struct esp_info *esp) 440 { 441 return ERR_PTR(-EOPNOTSUPP); 442 } 443 #endif 444 445 static int esp6_output_encap(struct xfrm_state *x, struct sk_buff *skb, 446 struct esp_info *esp) 447 { 448 struct xfrm_encap_tmpl *encap = x->encap; 449 struct ip_esp_hdr *esph; 450 __be16 sport, dport; 451 int encap_type; 452 453 spin_lock_bh(&x->lock); 454 sport = encap->encap_sport; 455 dport = encap->encap_dport; 456 encap_type = encap->encap_type; 457 spin_unlock_bh(&x->lock); 458 459 switch (encap_type) { 460 default: 461 case UDP_ENCAP_ESPINUDP: 462 case UDP_ENCAP_ESPINUDP_NON_IKE: 463 esph = esp6_output_udp_encap(skb, encap_type, esp, sport, dport); 464 break; 465 case TCP_ENCAP_ESPINTCP: 466 esph = esp6_output_tcp_encap(x, skb, esp); 467 break; 468 } 469 470 if (IS_ERR(esph)) 471 return PTR_ERR(esph); 472 473 esp->esph = esph; 474 475 return 0; 476 } 477 478 int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 479 { 480 u8 *tail; 481 int nfrags; 482 int esph_offset; 483 struct page *page; 484 struct sk_buff *trailer; 485 int tailen = esp->tailen; 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 if (!skb_cloned(skb)) { 495 if (tailen <= skb_tailroom(skb)) { 496 nfrags = 1; 497 trailer = skb; 498 tail = skb_tail_pointer(trailer); 499 500 goto skip_cow; 501 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 502 && !skb_has_frag_list(skb)) { 503 int allocsize; 504 struct sock *sk = skb->sk; 505 struct page_frag *pfrag = &x->xfrag; 506 507 esp->inplace = false; 508 509 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 510 511 spin_lock_bh(&x->lock); 512 513 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 514 spin_unlock_bh(&x->lock); 515 goto cow; 516 } 517 518 page = pfrag->page; 519 get_page(page); 520 521 tail = page_address(page) + pfrag->offset; 522 523 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 524 525 nfrags = skb_shinfo(skb)->nr_frags; 526 527 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 528 tailen); 529 skb_shinfo(skb)->nr_frags = ++nfrags; 530 531 pfrag->offset = pfrag->offset + allocsize; 532 533 spin_unlock_bh(&x->lock); 534 535 nfrags++; 536 537 skb->len += tailen; 538 skb->data_len += tailen; 539 skb->truesize += tailen; 540 if (sk && sk_fullsock(sk)) 541 refcount_add(tailen, &sk->sk_wmem_alloc); 542 543 goto out; 544 } 545 } 546 547 cow: 548 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 549 550 nfrags = skb_cow_data(skb, tailen, &trailer); 551 if (nfrags < 0) 552 goto out; 553 tail = skb_tail_pointer(trailer); 554 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 555 556 skip_cow: 557 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 558 pskb_put(skb, trailer, tailen); 559 560 out: 561 return nfrags; 562 } 563 EXPORT_SYMBOL_GPL(esp6_output_head); 564 565 int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 566 { 567 u8 *iv; 568 int alen; 569 void *tmp; 570 int ivlen; 571 int assoclen; 572 int extralen; 573 struct page *page; 574 struct ip_esp_hdr *esph; 575 struct aead_request *req; 576 struct crypto_aead *aead; 577 struct scatterlist *sg, *dsg; 578 struct esp_output_extra *extra; 579 int err = -ENOMEM; 580 581 assoclen = sizeof(struct ip_esp_hdr); 582 extralen = 0; 583 584 if (x->props.flags & XFRM_STATE_ESN) { 585 extralen += sizeof(*extra); 586 assoclen += sizeof(__be32); 587 } 588 589 aead = x->data; 590 alen = crypto_aead_authsize(aead); 591 ivlen = crypto_aead_ivsize(aead); 592 593 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 594 if (!tmp) 595 goto error; 596 597 extra = esp_tmp_extra(tmp); 598 iv = esp_tmp_iv(aead, tmp, extralen); 599 req = esp_tmp_req(aead, iv); 600 sg = esp_req_sg(aead, req); 601 602 if (esp->inplace) 603 dsg = sg; 604 else 605 dsg = &sg[esp->nfrags]; 606 607 esph = esp_output_set_esn(skb, x, esp->esph, extra); 608 esp->esph = esph; 609 610 sg_init_table(sg, esp->nfrags); 611 err = skb_to_sgvec(skb, sg, 612 (unsigned char *)esph - skb->data, 613 assoclen + ivlen + esp->clen + alen); 614 if (unlikely(err < 0)) 615 goto error_free; 616 617 if (!esp->inplace) { 618 int allocsize; 619 struct page_frag *pfrag = &x->xfrag; 620 621 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 622 623 spin_lock_bh(&x->lock); 624 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 625 spin_unlock_bh(&x->lock); 626 goto error_free; 627 } 628 629 skb_shinfo(skb)->nr_frags = 1; 630 631 page = pfrag->page; 632 get_page(page); 633 /* replace page frags in skb with new page */ 634 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 635 pfrag->offset = pfrag->offset + allocsize; 636 spin_unlock_bh(&x->lock); 637 638 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 639 err = skb_to_sgvec(skb, dsg, 640 (unsigned char *)esph - skb->data, 641 assoclen + ivlen + esp->clen + alen); 642 if (unlikely(err < 0)) 643 goto error_free; 644 } 645 646 if ((x->props.flags & XFRM_STATE_ESN)) 647 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 648 else 649 aead_request_set_callback(req, 0, esp_output_done, skb); 650 651 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 652 aead_request_set_ad(req, assoclen); 653 654 memset(iv, 0, ivlen); 655 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 656 min(ivlen, 8)); 657 658 ESP_SKB_CB(skb)->tmp = tmp; 659 err = crypto_aead_encrypt(req); 660 661 switch (err) { 662 case -EINPROGRESS: 663 goto error; 664 665 case -ENOSPC: 666 err = NET_XMIT_DROP; 667 break; 668 669 case 0: 670 if ((x->props.flags & XFRM_STATE_ESN)) 671 esp_output_restore_header(skb); 672 esp_output_encap_csum(skb); 673 } 674 675 if (sg != dsg) 676 esp_ssg_unref(x, tmp); 677 678 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 679 err = esp_output_tail_tcp(x, skb); 680 681 error_free: 682 kfree(tmp); 683 error: 684 return err; 685 } 686 EXPORT_SYMBOL_GPL(esp6_output_tail); 687 688 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) 689 { 690 int alen; 691 int blksize; 692 struct ip_esp_hdr *esph; 693 struct crypto_aead *aead; 694 struct esp_info esp; 695 696 esp.inplace = true; 697 698 esp.proto = *skb_mac_header(skb); 699 *skb_mac_header(skb) = IPPROTO_ESP; 700 701 /* skb is pure payload to encrypt */ 702 703 aead = x->data; 704 alen = crypto_aead_authsize(aead); 705 706 esp.tfclen = 0; 707 if (x->tfcpad) { 708 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 709 u32 padto; 710 711 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 712 if (skb->len < padto) 713 esp.tfclen = padto - skb->len; 714 } 715 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 716 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 717 esp.plen = esp.clen - skb->len - esp.tfclen; 718 esp.tailen = esp.tfclen + esp.plen + alen; 719 720 esp.esph = ip_esp_hdr(skb); 721 722 esp.nfrags = esp6_output_head(x, skb, &esp); 723 if (esp.nfrags < 0) 724 return esp.nfrags; 725 726 esph = esp.esph; 727 esph->spi = x->id.spi; 728 729 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 730 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 731 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 732 733 skb_push(skb, -skb_network_offset(skb)); 734 735 return esp6_output_tail(x, skb, &esp); 736 } 737 738 static inline int esp_remove_trailer(struct sk_buff *skb) 739 { 740 struct xfrm_state *x = xfrm_input_state(skb); 741 struct xfrm_offload *xo = xfrm_offload(skb); 742 struct crypto_aead *aead = x->data; 743 int alen, hlen, elen; 744 int padlen, trimlen; 745 __wsum csumdiff; 746 u8 nexthdr[2]; 747 int ret; 748 749 alen = crypto_aead_authsize(aead); 750 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 751 elen = skb->len - hlen; 752 753 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) { 754 ret = xo->proto; 755 goto out; 756 } 757 758 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2); 759 BUG_ON(ret); 760 761 ret = -EINVAL; 762 padlen = nexthdr[0]; 763 if (padlen + 2 + alen >= elen) { 764 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 765 padlen + 2, elen - alen); 766 goto out; 767 } 768 769 trimlen = alen + padlen + 2; 770 if (skb->ip_summed == CHECKSUM_COMPLETE) { 771 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 772 skb->csum = csum_block_sub(skb->csum, csumdiff, 773 skb->len - trimlen); 774 } 775 pskb_trim(skb, skb->len - trimlen); 776 777 ret = nexthdr[1]; 778 779 out: 780 return ret; 781 } 782 783 int esp6_input_done2(struct sk_buff *skb, int err) 784 { 785 struct xfrm_state *x = xfrm_input_state(skb); 786 struct xfrm_offload *xo = xfrm_offload(skb); 787 struct crypto_aead *aead = x->data; 788 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 789 int hdr_len = skb_network_header_len(skb); 790 791 if (!xo || !(xo->flags & CRYPTO_DONE)) 792 kfree(ESP_SKB_CB(skb)->tmp); 793 794 if (unlikely(err)) 795 goto out; 796 797 err = esp_remove_trailer(skb); 798 if (unlikely(err < 0)) 799 goto out; 800 801 if (x->encap) { 802 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 803 int offset = skb_network_offset(skb) + sizeof(*ip6h); 804 struct xfrm_encap_tmpl *encap = x->encap; 805 u8 nexthdr = ip6h->nexthdr; 806 __be16 frag_off, source; 807 struct udphdr *uh; 808 struct tcphdr *th; 809 810 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); 811 uh = (void *)(skb->data + offset); 812 th = (void *)(skb->data + offset); 813 hdr_len += offset; 814 815 switch (x->encap->encap_type) { 816 case TCP_ENCAP_ESPINTCP: 817 source = th->source; 818 break; 819 case UDP_ENCAP_ESPINUDP: 820 case UDP_ENCAP_ESPINUDP_NON_IKE: 821 source = uh->source; 822 break; 823 default: 824 WARN_ON_ONCE(1); 825 err = -EINVAL; 826 goto out; 827 } 828 829 /* 830 * 1) if the NAT-T peer's IP or port changed then 831 * advertize the change to the keying daemon. 832 * This is an inbound SA, so just compare 833 * SRC ports. 834 */ 835 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) || 836 source != encap->encap_sport) { 837 xfrm_address_t ipaddr; 838 839 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6)); 840 km_new_mapping(x, &ipaddr, source); 841 842 /* XXX: perhaps add an extra 843 * policy check here, to see 844 * if we should allow or 845 * reject a packet from a 846 * different source 847 * address/port. 848 */ 849 } 850 851 /* 852 * 2) ignore UDP/TCP checksums in case 853 * of NAT-T in Transport Mode, or 854 * perform other post-processing fixes 855 * as per draft-ietf-ipsec-udp-encaps-06, 856 * section 3.1.2 857 */ 858 if (x->props.mode == XFRM_MODE_TRANSPORT) 859 skb->ip_summed = CHECKSUM_UNNECESSARY; 860 } 861 862 skb_postpull_rcsum(skb, skb_network_header(skb), 863 skb_network_header_len(skb)); 864 skb_pull_rcsum(skb, hlen); 865 if (x->props.mode == XFRM_MODE_TUNNEL) 866 skb_reset_transport_header(skb); 867 else 868 skb_set_transport_header(skb, -hdr_len); 869 870 /* RFC4303: Drop dummy packets without any error */ 871 if (err == IPPROTO_NONE) 872 err = -EINVAL; 873 874 out: 875 return err; 876 } 877 EXPORT_SYMBOL_GPL(esp6_input_done2); 878 879 static void esp_input_done(struct crypto_async_request *base, int err) 880 { 881 struct sk_buff *skb = base->data; 882 883 xfrm_input_resume(skb, esp6_input_done2(skb, err)); 884 } 885 886 static void esp_input_restore_header(struct sk_buff *skb) 887 { 888 esp_restore_header(skb, 0); 889 __skb_pull(skb, 4); 890 } 891 892 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 893 { 894 struct xfrm_state *x = xfrm_input_state(skb); 895 896 /* For ESN we move the header forward by 4 bytes to 897 * accomodate the high bits. We will move it back after 898 * decryption. 899 */ 900 if ((x->props.flags & XFRM_STATE_ESN)) { 901 struct ip_esp_hdr *esph = skb_push(skb, 4); 902 903 *seqhi = esph->spi; 904 esph->spi = esph->seq_no; 905 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 906 } 907 } 908 909 static void esp_input_done_esn(struct crypto_async_request *base, int err) 910 { 911 struct sk_buff *skb = base->data; 912 913 esp_input_restore_header(skb); 914 esp_input_done(base, err); 915 } 916 917 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) 918 { 919 struct crypto_aead *aead = x->data; 920 struct aead_request *req; 921 struct sk_buff *trailer; 922 int ivlen = crypto_aead_ivsize(aead); 923 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 924 int nfrags; 925 int assoclen; 926 int seqhilen; 927 int ret = 0; 928 void *tmp; 929 __be32 *seqhi; 930 u8 *iv; 931 struct scatterlist *sg; 932 933 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) { 934 ret = -EINVAL; 935 goto out; 936 } 937 938 if (elen <= 0) { 939 ret = -EINVAL; 940 goto out; 941 } 942 943 assoclen = sizeof(struct ip_esp_hdr); 944 seqhilen = 0; 945 946 if (x->props.flags & XFRM_STATE_ESN) { 947 seqhilen += sizeof(__be32); 948 assoclen += seqhilen; 949 } 950 951 if (!skb_cloned(skb)) { 952 if (!skb_is_nonlinear(skb)) { 953 nfrags = 1; 954 955 goto skip_cow; 956 } else if (!skb_has_frag_list(skb)) { 957 nfrags = skb_shinfo(skb)->nr_frags; 958 nfrags++; 959 960 goto skip_cow; 961 } 962 } 963 964 nfrags = skb_cow_data(skb, 0, &trailer); 965 if (nfrags < 0) { 966 ret = -EINVAL; 967 goto out; 968 } 969 970 skip_cow: 971 ret = -ENOMEM; 972 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 973 if (!tmp) 974 goto out; 975 976 ESP_SKB_CB(skb)->tmp = tmp; 977 seqhi = esp_tmp_extra(tmp); 978 iv = esp_tmp_iv(aead, tmp, seqhilen); 979 req = esp_tmp_req(aead, iv); 980 sg = esp_req_sg(aead, req); 981 982 esp_input_set_header(skb, seqhi); 983 984 sg_init_table(sg, nfrags); 985 ret = skb_to_sgvec(skb, sg, 0, skb->len); 986 if (unlikely(ret < 0)) { 987 kfree(tmp); 988 goto out; 989 } 990 991 skb->ip_summed = CHECKSUM_NONE; 992 993 if ((x->props.flags & XFRM_STATE_ESN)) 994 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 995 else 996 aead_request_set_callback(req, 0, esp_input_done, skb); 997 998 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 999 aead_request_set_ad(req, assoclen); 1000 1001 ret = crypto_aead_decrypt(req); 1002 if (ret == -EINPROGRESS) 1003 goto out; 1004 1005 if ((x->props.flags & XFRM_STATE_ESN)) 1006 esp_input_restore_header(skb); 1007 1008 ret = esp6_input_done2(skb, ret); 1009 1010 out: 1011 return ret; 1012 } 1013 1014 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 1015 u8 type, u8 code, int offset, __be32 info) 1016 { 1017 struct net *net = dev_net(skb->dev); 1018 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 1019 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset); 1020 struct xfrm_state *x; 1021 1022 if (type != ICMPV6_PKT_TOOBIG && 1023 type != NDISC_REDIRECT) 1024 return 0; 1025 1026 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 1027 esph->spi, IPPROTO_ESP, AF_INET6); 1028 if (!x) 1029 return 0; 1030 1031 if (type == NDISC_REDIRECT) 1032 ip6_redirect(skb, net, skb->dev->ifindex, 0, 1033 sock_net_uid(net, NULL)); 1034 else 1035 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 1036 xfrm_state_put(x); 1037 1038 return 0; 1039 } 1040 1041 static void esp6_destroy(struct xfrm_state *x) 1042 { 1043 struct crypto_aead *aead = x->data; 1044 1045 if (!aead) 1046 return; 1047 1048 crypto_free_aead(aead); 1049 } 1050 1051 static int esp_init_aead(struct xfrm_state *x) 1052 { 1053 char aead_name[CRYPTO_MAX_ALG_NAME]; 1054 struct crypto_aead *aead; 1055 int err; 1056 1057 err = -ENAMETOOLONG; 1058 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1059 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) 1060 goto error; 1061 1062 aead = crypto_alloc_aead(aead_name, 0, 0); 1063 err = PTR_ERR(aead); 1064 if (IS_ERR(aead)) 1065 goto error; 1066 1067 x->data = aead; 1068 1069 err = crypto_aead_setkey(aead, x->aead->alg_key, 1070 (x->aead->alg_key_len + 7) / 8); 1071 if (err) 1072 goto error; 1073 1074 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1075 if (err) 1076 goto error; 1077 1078 error: 1079 return err; 1080 } 1081 1082 static int esp_init_authenc(struct xfrm_state *x) 1083 { 1084 struct crypto_aead *aead; 1085 struct crypto_authenc_key_param *param; 1086 struct rtattr *rta; 1087 char *key; 1088 char *p; 1089 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1090 unsigned int keylen; 1091 int err; 1092 1093 err = -EINVAL; 1094 if (!x->ealg) 1095 goto error; 1096 1097 err = -ENAMETOOLONG; 1098 1099 if ((x->props.flags & XFRM_STATE_ESN)) { 1100 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1101 "%s%sauthencesn(%s,%s)%s", 1102 x->geniv ?: "", x->geniv ? "(" : "", 1103 x->aalg ? x->aalg->alg_name : "digest_null", 1104 x->ealg->alg_name, 1105 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1106 goto error; 1107 } else { 1108 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1109 "%s%sauthenc(%s,%s)%s", 1110 x->geniv ?: "", x->geniv ? "(" : "", 1111 x->aalg ? x->aalg->alg_name : "digest_null", 1112 x->ealg->alg_name, 1113 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1114 goto error; 1115 } 1116 1117 aead = crypto_alloc_aead(authenc_name, 0, 0); 1118 err = PTR_ERR(aead); 1119 if (IS_ERR(aead)) 1120 goto error; 1121 1122 x->data = aead; 1123 1124 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1125 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1126 err = -ENOMEM; 1127 key = kmalloc(keylen, GFP_KERNEL); 1128 if (!key) 1129 goto error; 1130 1131 p = key; 1132 rta = (void *)p; 1133 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1134 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1135 param = RTA_DATA(rta); 1136 p += RTA_SPACE(sizeof(*param)); 1137 1138 if (x->aalg) { 1139 struct xfrm_algo_desc *aalg_desc; 1140 1141 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1142 p += (x->aalg->alg_key_len + 7) / 8; 1143 1144 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1145 BUG_ON(!aalg_desc); 1146 1147 err = -EINVAL; 1148 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1149 crypto_aead_authsize(aead)) { 1150 pr_info("ESP: %s digestsize %u != %hu\n", 1151 x->aalg->alg_name, 1152 crypto_aead_authsize(aead), 1153 aalg_desc->uinfo.auth.icv_fullbits / 8); 1154 goto free_key; 1155 } 1156 1157 err = crypto_aead_setauthsize( 1158 aead, x->aalg->alg_trunc_len / 8); 1159 if (err) 1160 goto free_key; 1161 } 1162 1163 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1164 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1165 1166 err = crypto_aead_setkey(aead, key, keylen); 1167 1168 free_key: 1169 kfree(key); 1170 1171 error: 1172 return err; 1173 } 1174 1175 static int esp6_init_state(struct xfrm_state *x) 1176 { 1177 struct crypto_aead *aead; 1178 u32 align; 1179 int err; 1180 1181 x->data = NULL; 1182 1183 if (x->aead) 1184 err = esp_init_aead(x); 1185 else 1186 err = esp_init_authenc(x); 1187 1188 if (err) 1189 goto error; 1190 1191 aead = x->data; 1192 1193 x->props.header_len = sizeof(struct ip_esp_hdr) + 1194 crypto_aead_ivsize(aead); 1195 switch (x->props.mode) { 1196 case XFRM_MODE_BEET: 1197 if (x->sel.family != AF_INET6) 1198 x->props.header_len += IPV4_BEET_PHMAXLEN + 1199 (sizeof(struct ipv6hdr) - sizeof(struct iphdr)); 1200 break; 1201 default: 1202 case XFRM_MODE_TRANSPORT: 1203 break; 1204 case XFRM_MODE_TUNNEL: 1205 x->props.header_len += sizeof(struct ipv6hdr); 1206 break; 1207 } 1208 1209 if (x->encap) { 1210 struct xfrm_encap_tmpl *encap = x->encap; 1211 1212 switch (encap->encap_type) { 1213 default: 1214 err = -EINVAL; 1215 goto error; 1216 case UDP_ENCAP_ESPINUDP: 1217 x->props.header_len += sizeof(struct udphdr); 1218 break; 1219 case UDP_ENCAP_ESPINUDP_NON_IKE: 1220 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 1221 break; 1222 #ifdef CONFIG_INET6_ESPINTCP 1223 case TCP_ENCAP_ESPINTCP: 1224 /* only the length field, TCP encap is done by 1225 * the socket 1226 */ 1227 x->props.header_len += 2; 1228 break; 1229 #endif 1230 } 1231 } 1232 1233 align = ALIGN(crypto_aead_blocksize(aead), 4); 1234 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1235 1236 error: 1237 return err; 1238 } 1239 1240 static int esp6_rcv_cb(struct sk_buff *skb, int err) 1241 { 1242 return 0; 1243 } 1244 1245 static const struct xfrm_type esp6_type = { 1246 .description = "ESP6", 1247 .owner = THIS_MODULE, 1248 .proto = IPPROTO_ESP, 1249 .flags = XFRM_TYPE_REPLAY_PROT, 1250 .init_state = esp6_init_state, 1251 .destructor = esp6_destroy, 1252 .input = esp6_input, 1253 .output = esp6_output, 1254 .hdr_offset = xfrm6_find_1stfragopt, 1255 }; 1256 1257 static struct xfrm6_protocol esp6_protocol = { 1258 .handler = xfrm6_rcv, 1259 .input_handler = xfrm_input, 1260 .cb_handler = esp6_rcv_cb, 1261 .err_handler = esp6_err, 1262 .priority = 0, 1263 }; 1264 1265 static int __init esp6_init(void) 1266 { 1267 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { 1268 pr_info("%s: can't add xfrm type\n", __func__); 1269 return -EAGAIN; 1270 } 1271 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) { 1272 pr_info("%s: can't add protocol\n", __func__); 1273 xfrm_unregister_type(&esp6_type, AF_INET6); 1274 return -EAGAIN; 1275 } 1276 1277 return 0; 1278 } 1279 1280 static void __exit esp6_fini(void) 1281 { 1282 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0) 1283 pr_info("%s: can't remove protocol\n", __func__); 1284 xfrm_unregister_type(&esp6_type, AF_INET6); 1285 } 1286 1287 module_init(esp6_init); 1288 module_exit(esp6_fini); 1289 1290 MODULE_LICENSE("GPL"); 1291 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP); 1292