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; 485 486 if (x->encap) { 487 int err = esp6_output_encap(x, skb, esp); 488 489 if (err < 0) 490 return err; 491 } 492 493 if (!skb_cloned(skb)) { 494 if (tailen <= skb_tailroom(skb)) { 495 nfrags = 1; 496 trailer = skb; 497 tail = skb_tail_pointer(trailer); 498 499 goto skip_cow; 500 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 501 && !skb_has_frag_list(skb)) { 502 int allocsize; 503 struct sock *sk = skb->sk; 504 struct page_frag *pfrag = &x->xfrag; 505 506 esp->inplace = false; 507 508 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 509 510 spin_lock_bh(&x->lock); 511 512 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 513 spin_unlock_bh(&x->lock); 514 goto cow; 515 } 516 517 page = pfrag->page; 518 get_page(page); 519 520 tail = page_address(page) + pfrag->offset; 521 522 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 523 524 nfrags = skb_shinfo(skb)->nr_frags; 525 526 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 527 tailen); 528 skb_shinfo(skb)->nr_frags = ++nfrags; 529 530 pfrag->offset = pfrag->offset + allocsize; 531 532 spin_unlock_bh(&x->lock); 533 534 nfrags++; 535 536 skb->len += tailen; 537 skb->data_len += tailen; 538 skb->truesize += tailen; 539 if (sk && sk_fullsock(sk)) 540 refcount_add(tailen, &sk->sk_wmem_alloc); 541 542 goto out; 543 } 544 } 545 546 cow: 547 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 548 549 nfrags = skb_cow_data(skb, tailen, &trailer); 550 if (nfrags < 0) 551 goto out; 552 tail = skb_tail_pointer(trailer); 553 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 554 555 skip_cow: 556 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 557 pskb_put(skb, trailer, tailen); 558 559 out: 560 return nfrags; 561 } 562 EXPORT_SYMBOL_GPL(esp6_output_head); 563 564 int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 565 { 566 u8 *iv; 567 int alen; 568 void *tmp; 569 int ivlen; 570 int assoclen; 571 int extralen; 572 struct page *page; 573 struct ip_esp_hdr *esph; 574 struct aead_request *req; 575 struct crypto_aead *aead; 576 struct scatterlist *sg, *dsg; 577 struct esp_output_extra *extra; 578 int err = -ENOMEM; 579 580 assoclen = sizeof(struct ip_esp_hdr); 581 extralen = 0; 582 583 if (x->props.flags & XFRM_STATE_ESN) { 584 extralen += sizeof(*extra); 585 assoclen += sizeof(__be32); 586 } 587 588 aead = x->data; 589 alen = crypto_aead_authsize(aead); 590 ivlen = crypto_aead_ivsize(aead); 591 592 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 593 if (!tmp) 594 goto error; 595 596 extra = esp_tmp_extra(tmp); 597 iv = esp_tmp_iv(aead, tmp, extralen); 598 req = esp_tmp_req(aead, iv); 599 sg = esp_req_sg(aead, req); 600 601 if (esp->inplace) 602 dsg = sg; 603 else 604 dsg = &sg[esp->nfrags]; 605 606 esph = esp_output_set_esn(skb, x, esp->esph, extra); 607 esp->esph = esph; 608 609 sg_init_table(sg, esp->nfrags); 610 err = skb_to_sgvec(skb, sg, 611 (unsigned char *)esph - skb->data, 612 assoclen + ivlen + esp->clen + alen); 613 if (unlikely(err < 0)) 614 goto error_free; 615 616 if (!esp->inplace) { 617 int allocsize; 618 struct page_frag *pfrag = &x->xfrag; 619 620 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 621 622 spin_lock_bh(&x->lock); 623 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 624 spin_unlock_bh(&x->lock); 625 goto error_free; 626 } 627 628 skb_shinfo(skb)->nr_frags = 1; 629 630 page = pfrag->page; 631 get_page(page); 632 /* replace page frags in skb with new page */ 633 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 634 pfrag->offset = pfrag->offset + allocsize; 635 spin_unlock_bh(&x->lock); 636 637 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 638 err = skb_to_sgvec(skb, dsg, 639 (unsigned char *)esph - skb->data, 640 assoclen + ivlen + esp->clen + alen); 641 if (unlikely(err < 0)) 642 goto error_free; 643 } 644 645 if ((x->props.flags & XFRM_STATE_ESN)) 646 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 647 else 648 aead_request_set_callback(req, 0, esp_output_done, skb); 649 650 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 651 aead_request_set_ad(req, assoclen); 652 653 memset(iv, 0, ivlen); 654 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 655 min(ivlen, 8)); 656 657 ESP_SKB_CB(skb)->tmp = tmp; 658 err = crypto_aead_encrypt(req); 659 660 switch (err) { 661 case -EINPROGRESS: 662 goto error; 663 664 case -ENOSPC: 665 err = NET_XMIT_DROP; 666 break; 667 668 case 0: 669 if ((x->props.flags & XFRM_STATE_ESN)) 670 esp_output_restore_header(skb); 671 esp_output_encap_csum(skb); 672 } 673 674 if (sg != dsg) 675 esp_ssg_unref(x, tmp); 676 677 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 678 err = esp_output_tail_tcp(x, skb); 679 680 error_free: 681 kfree(tmp); 682 error: 683 return err; 684 } 685 EXPORT_SYMBOL_GPL(esp6_output_tail); 686 687 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) 688 { 689 int alen; 690 int blksize; 691 struct ip_esp_hdr *esph; 692 struct crypto_aead *aead; 693 struct esp_info esp; 694 695 esp.inplace = true; 696 697 esp.proto = *skb_mac_header(skb); 698 *skb_mac_header(skb) = IPPROTO_ESP; 699 700 /* skb is pure payload to encrypt */ 701 702 aead = x->data; 703 alen = crypto_aead_authsize(aead); 704 705 esp.tfclen = 0; 706 if (x->tfcpad) { 707 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 708 u32 padto; 709 710 padto = min(x->tfcpad, __xfrm_state_mtu(x, dst->child_mtu_cached)); 711 if (skb->len < padto) 712 esp.tfclen = padto - skb->len; 713 } 714 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 715 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 716 esp.plen = esp.clen - skb->len - esp.tfclen; 717 esp.tailen = esp.tfclen + esp.plen + alen; 718 719 esp.esph = ip_esp_hdr(skb); 720 721 esp.nfrags = esp6_output_head(x, skb, &esp); 722 if (esp.nfrags < 0) 723 return esp.nfrags; 724 725 esph = esp.esph; 726 esph->spi = x->id.spi; 727 728 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 729 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 730 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 731 732 skb_push(skb, -skb_network_offset(skb)); 733 734 return esp6_output_tail(x, skb, &esp); 735 } 736 737 static inline int esp_remove_trailer(struct sk_buff *skb) 738 { 739 struct xfrm_state *x = xfrm_input_state(skb); 740 struct xfrm_offload *xo = xfrm_offload(skb); 741 struct crypto_aead *aead = x->data; 742 int alen, hlen, elen; 743 int padlen, trimlen; 744 __wsum csumdiff; 745 u8 nexthdr[2]; 746 int ret; 747 748 alen = crypto_aead_authsize(aead); 749 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 750 elen = skb->len - hlen; 751 752 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) { 753 ret = xo->proto; 754 goto out; 755 } 756 757 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2); 758 BUG_ON(ret); 759 760 ret = -EINVAL; 761 padlen = nexthdr[0]; 762 if (padlen + 2 + alen >= elen) { 763 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 764 padlen + 2, elen - alen); 765 goto out; 766 } 767 768 trimlen = alen + padlen + 2; 769 if (skb->ip_summed == CHECKSUM_COMPLETE) { 770 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 771 skb->csum = csum_block_sub(skb->csum, csumdiff, 772 skb->len - trimlen); 773 } 774 pskb_trim(skb, skb->len - trimlen); 775 776 ret = nexthdr[1]; 777 778 out: 779 return ret; 780 } 781 782 int esp6_input_done2(struct sk_buff *skb, int err) 783 { 784 struct xfrm_state *x = xfrm_input_state(skb); 785 struct xfrm_offload *xo = xfrm_offload(skb); 786 struct crypto_aead *aead = x->data; 787 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 788 int hdr_len = skb_network_header_len(skb); 789 790 if (!xo || !(xo->flags & CRYPTO_DONE)) 791 kfree(ESP_SKB_CB(skb)->tmp); 792 793 if (unlikely(err)) 794 goto out; 795 796 err = esp_remove_trailer(skb); 797 if (unlikely(err < 0)) 798 goto out; 799 800 if (x->encap) { 801 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 802 int offset = skb_network_offset(skb) + sizeof(*ip6h); 803 struct xfrm_encap_tmpl *encap = x->encap; 804 u8 nexthdr = ip6h->nexthdr; 805 __be16 frag_off, source; 806 struct udphdr *uh; 807 struct tcphdr *th; 808 809 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); 810 811 if (offset < 0) { 812 err = -EINVAL; 813 goto out; 814 } 815 816 uh = (void *)(skb->data + offset); 817 th = (void *)(skb->data + offset); 818 hdr_len += offset; 819 820 switch (x->encap->encap_type) { 821 case TCP_ENCAP_ESPINTCP: 822 source = th->source; 823 break; 824 case UDP_ENCAP_ESPINUDP: 825 case UDP_ENCAP_ESPINUDP_NON_IKE: 826 source = uh->source; 827 break; 828 default: 829 WARN_ON_ONCE(1); 830 err = -EINVAL; 831 goto out; 832 } 833 834 /* 835 * 1) if the NAT-T peer's IP or port changed then 836 * advertize the change to the keying daemon. 837 * This is an inbound SA, so just compare 838 * SRC ports. 839 */ 840 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) || 841 source != encap->encap_sport) { 842 xfrm_address_t ipaddr; 843 844 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6)); 845 km_new_mapping(x, &ipaddr, source); 846 847 /* XXX: perhaps add an extra 848 * policy check here, to see 849 * if we should allow or 850 * reject a packet from a 851 * different source 852 * address/port. 853 */ 854 } 855 856 /* 857 * 2) ignore UDP/TCP checksums in case 858 * of NAT-T in Transport Mode, or 859 * perform other post-processing fixes 860 * as per draft-ietf-ipsec-udp-encaps-06, 861 * section 3.1.2 862 */ 863 if (x->props.mode == XFRM_MODE_TRANSPORT) 864 skb->ip_summed = CHECKSUM_UNNECESSARY; 865 } 866 867 skb_postpull_rcsum(skb, skb_network_header(skb), 868 skb_network_header_len(skb)); 869 skb_pull_rcsum(skb, hlen); 870 if (x->props.mode == XFRM_MODE_TUNNEL) 871 skb_reset_transport_header(skb); 872 else 873 skb_set_transport_header(skb, -hdr_len); 874 875 /* RFC4303: Drop dummy packets without any error */ 876 if (err == IPPROTO_NONE) 877 err = -EINVAL; 878 879 out: 880 return err; 881 } 882 EXPORT_SYMBOL_GPL(esp6_input_done2); 883 884 static void esp_input_done(struct crypto_async_request *base, int err) 885 { 886 struct sk_buff *skb = base->data; 887 888 xfrm_input_resume(skb, esp6_input_done2(skb, err)); 889 } 890 891 static void esp_input_restore_header(struct sk_buff *skb) 892 { 893 esp_restore_header(skb, 0); 894 __skb_pull(skb, 4); 895 } 896 897 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 898 { 899 struct xfrm_state *x = xfrm_input_state(skb); 900 901 /* For ESN we move the header forward by 4 bytes to 902 * accomodate the high bits. We will move it back after 903 * decryption. 904 */ 905 if ((x->props.flags & XFRM_STATE_ESN)) { 906 struct ip_esp_hdr *esph = skb_push(skb, 4); 907 908 *seqhi = esph->spi; 909 esph->spi = esph->seq_no; 910 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 911 } 912 } 913 914 static void esp_input_done_esn(struct crypto_async_request *base, int err) 915 { 916 struct sk_buff *skb = base->data; 917 918 esp_input_restore_header(skb); 919 esp_input_done(base, err); 920 } 921 922 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) 923 { 924 struct crypto_aead *aead = x->data; 925 struct aead_request *req; 926 struct sk_buff *trailer; 927 int ivlen = crypto_aead_ivsize(aead); 928 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 929 int nfrags; 930 int assoclen; 931 int seqhilen; 932 int ret = 0; 933 void *tmp; 934 __be32 *seqhi; 935 u8 *iv; 936 struct scatterlist *sg; 937 938 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) { 939 ret = -EINVAL; 940 goto out; 941 } 942 943 if (elen <= 0) { 944 ret = -EINVAL; 945 goto out; 946 } 947 948 assoclen = sizeof(struct ip_esp_hdr); 949 seqhilen = 0; 950 951 if (x->props.flags & XFRM_STATE_ESN) { 952 seqhilen += sizeof(__be32); 953 assoclen += seqhilen; 954 } 955 956 if (!skb_cloned(skb)) { 957 if (!skb_is_nonlinear(skb)) { 958 nfrags = 1; 959 960 goto skip_cow; 961 } else if (!skb_has_frag_list(skb)) { 962 nfrags = skb_shinfo(skb)->nr_frags; 963 nfrags++; 964 965 goto skip_cow; 966 } 967 } 968 969 nfrags = skb_cow_data(skb, 0, &trailer); 970 if (nfrags < 0) { 971 ret = -EINVAL; 972 goto out; 973 } 974 975 skip_cow: 976 ret = -ENOMEM; 977 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 978 if (!tmp) 979 goto out; 980 981 ESP_SKB_CB(skb)->tmp = tmp; 982 seqhi = esp_tmp_extra(tmp); 983 iv = esp_tmp_iv(aead, tmp, seqhilen); 984 req = esp_tmp_req(aead, iv); 985 sg = esp_req_sg(aead, req); 986 987 esp_input_set_header(skb, seqhi); 988 989 sg_init_table(sg, nfrags); 990 ret = skb_to_sgvec(skb, sg, 0, skb->len); 991 if (unlikely(ret < 0)) { 992 kfree(tmp); 993 goto out; 994 } 995 996 skb->ip_summed = CHECKSUM_NONE; 997 998 if ((x->props.flags & XFRM_STATE_ESN)) 999 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 1000 else 1001 aead_request_set_callback(req, 0, esp_input_done, skb); 1002 1003 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 1004 aead_request_set_ad(req, assoclen); 1005 1006 ret = crypto_aead_decrypt(req); 1007 if (ret == -EINPROGRESS) 1008 goto out; 1009 1010 if ((x->props.flags & XFRM_STATE_ESN)) 1011 esp_input_restore_header(skb); 1012 1013 ret = esp6_input_done2(skb, ret); 1014 1015 out: 1016 return ret; 1017 } 1018 1019 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 1020 u8 type, u8 code, int offset, __be32 info) 1021 { 1022 struct net *net = dev_net(skb->dev); 1023 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 1024 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset); 1025 struct xfrm_state *x; 1026 1027 if (type != ICMPV6_PKT_TOOBIG && 1028 type != NDISC_REDIRECT) 1029 return 0; 1030 1031 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 1032 esph->spi, IPPROTO_ESP, AF_INET6); 1033 if (!x) 1034 return 0; 1035 1036 if (type == NDISC_REDIRECT) 1037 ip6_redirect(skb, net, skb->dev->ifindex, 0, 1038 sock_net_uid(net, NULL)); 1039 else 1040 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 1041 xfrm_state_put(x); 1042 1043 return 0; 1044 } 1045 1046 static void esp6_destroy(struct xfrm_state *x) 1047 { 1048 struct crypto_aead *aead = x->data; 1049 1050 if (!aead) 1051 return; 1052 1053 crypto_free_aead(aead); 1054 } 1055 1056 static int esp_init_aead(struct xfrm_state *x) 1057 { 1058 char aead_name[CRYPTO_MAX_ALG_NAME]; 1059 struct crypto_aead *aead; 1060 int err; 1061 1062 err = -ENAMETOOLONG; 1063 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1064 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) 1065 goto error; 1066 1067 aead = crypto_alloc_aead(aead_name, 0, 0); 1068 err = PTR_ERR(aead); 1069 if (IS_ERR(aead)) 1070 goto error; 1071 1072 x->data = aead; 1073 1074 err = crypto_aead_setkey(aead, x->aead->alg_key, 1075 (x->aead->alg_key_len + 7) / 8); 1076 if (err) 1077 goto error; 1078 1079 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1080 if (err) 1081 goto error; 1082 1083 error: 1084 return err; 1085 } 1086 1087 static int esp_init_authenc(struct xfrm_state *x) 1088 { 1089 struct crypto_aead *aead; 1090 struct crypto_authenc_key_param *param; 1091 struct rtattr *rta; 1092 char *key; 1093 char *p; 1094 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1095 unsigned int keylen; 1096 int err; 1097 1098 err = -EINVAL; 1099 if (!x->ealg) 1100 goto error; 1101 1102 err = -ENAMETOOLONG; 1103 1104 if ((x->props.flags & XFRM_STATE_ESN)) { 1105 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1106 "%s%sauthencesn(%s,%s)%s", 1107 x->geniv ?: "", x->geniv ? "(" : "", 1108 x->aalg ? x->aalg->alg_name : "digest_null", 1109 x->ealg->alg_name, 1110 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1111 goto error; 1112 } else { 1113 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1114 "%s%sauthenc(%s,%s)%s", 1115 x->geniv ?: "", x->geniv ? "(" : "", 1116 x->aalg ? x->aalg->alg_name : "digest_null", 1117 x->ealg->alg_name, 1118 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1119 goto error; 1120 } 1121 1122 aead = crypto_alloc_aead(authenc_name, 0, 0); 1123 err = PTR_ERR(aead); 1124 if (IS_ERR(aead)) 1125 goto error; 1126 1127 x->data = aead; 1128 1129 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1130 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1131 err = -ENOMEM; 1132 key = kmalloc(keylen, GFP_KERNEL); 1133 if (!key) 1134 goto error; 1135 1136 p = key; 1137 rta = (void *)p; 1138 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1139 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1140 param = RTA_DATA(rta); 1141 p += RTA_SPACE(sizeof(*param)); 1142 1143 if (x->aalg) { 1144 struct xfrm_algo_desc *aalg_desc; 1145 1146 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1147 p += (x->aalg->alg_key_len + 7) / 8; 1148 1149 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1150 BUG_ON(!aalg_desc); 1151 1152 err = -EINVAL; 1153 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1154 crypto_aead_authsize(aead)) { 1155 pr_info("ESP: %s digestsize %u != %u\n", 1156 x->aalg->alg_name, 1157 crypto_aead_authsize(aead), 1158 aalg_desc->uinfo.auth.icv_fullbits / 8); 1159 goto free_key; 1160 } 1161 1162 err = crypto_aead_setauthsize( 1163 aead, x->aalg->alg_trunc_len / 8); 1164 if (err) 1165 goto free_key; 1166 } 1167 1168 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1169 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1170 1171 err = crypto_aead_setkey(aead, key, keylen); 1172 1173 free_key: 1174 kfree(key); 1175 1176 error: 1177 return err; 1178 } 1179 1180 static int esp6_init_state(struct xfrm_state *x) 1181 { 1182 struct crypto_aead *aead; 1183 u32 align; 1184 int err; 1185 1186 x->data = NULL; 1187 1188 if (x->aead) 1189 err = esp_init_aead(x); 1190 else 1191 err = esp_init_authenc(x); 1192 1193 if (err) 1194 goto error; 1195 1196 aead = x->data; 1197 1198 x->props.header_len = sizeof(struct ip_esp_hdr) + 1199 crypto_aead_ivsize(aead); 1200 switch (x->props.mode) { 1201 case XFRM_MODE_BEET: 1202 if (x->sel.family != AF_INET6) 1203 x->props.header_len += IPV4_BEET_PHMAXLEN + 1204 (sizeof(struct ipv6hdr) - sizeof(struct iphdr)); 1205 break; 1206 default: 1207 case XFRM_MODE_TRANSPORT: 1208 break; 1209 case XFRM_MODE_TUNNEL: 1210 x->props.header_len += sizeof(struct ipv6hdr); 1211 break; 1212 } 1213 1214 if (x->encap) { 1215 struct xfrm_encap_tmpl *encap = x->encap; 1216 1217 switch (encap->encap_type) { 1218 default: 1219 err = -EINVAL; 1220 goto error; 1221 case UDP_ENCAP_ESPINUDP: 1222 x->props.header_len += sizeof(struct udphdr); 1223 break; 1224 case UDP_ENCAP_ESPINUDP_NON_IKE: 1225 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 1226 break; 1227 #ifdef CONFIG_INET6_ESPINTCP 1228 case TCP_ENCAP_ESPINTCP: 1229 /* only the length field, TCP encap is done by 1230 * the socket 1231 */ 1232 x->props.header_len += 2; 1233 break; 1234 #endif 1235 } 1236 } 1237 1238 align = ALIGN(crypto_aead_blocksize(aead), 4); 1239 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1240 1241 error: 1242 return err; 1243 } 1244 1245 static int esp6_rcv_cb(struct sk_buff *skb, int err) 1246 { 1247 return 0; 1248 } 1249 1250 static const struct xfrm_type esp6_type = { 1251 .owner = THIS_MODULE, 1252 .proto = IPPROTO_ESP, 1253 .flags = XFRM_TYPE_REPLAY_PROT, 1254 .init_state = esp6_init_state, 1255 .destructor = esp6_destroy, 1256 .input = esp6_input, 1257 .output = esp6_output, 1258 }; 1259 1260 static struct xfrm6_protocol esp6_protocol = { 1261 .handler = xfrm6_rcv, 1262 .input_handler = xfrm_input, 1263 .cb_handler = esp6_rcv_cb, 1264 .err_handler = esp6_err, 1265 .priority = 0, 1266 }; 1267 1268 static int __init esp6_init(void) 1269 { 1270 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { 1271 pr_info("%s: can't add xfrm type\n", __func__); 1272 return -EAGAIN; 1273 } 1274 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) { 1275 pr_info("%s: can't add protocol\n", __func__); 1276 xfrm_unregister_type(&esp6_type, AF_INET6); 1277 return -EAGAIN; 1278 } 1279 1280 return 0; 1281 } 1282 1283 static void __exit esp6_fini(void) 1284 { 1285 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0) 1286 pr_info("%s: can't remove protocol\n", __func__); 1287 xfrm_unregister_type(&esp6_type, AF_INET6); 1288 } 1289 1290 module_init(esp6_init); 1291 module_exit(esp6_fini); 1292 1293 MODULE_LICENSE("GPL"); 1294 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP); 1295