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 u8 *vaddr; 482 int nfrags; 483 int esph_offset; 484 struct page *page; 485 struct sk_buff *trailer; 486 int tailen = esp->tailen; 487 488 if (x->encap) { 489 int err = esp6_output_encap(x, skb, esp); 490 491 if (err < 0) 492 return err; 493 } 494 495 if (!skb_cloned(skb)) { 496 if (tailen <= skb_tailroom(skb)) { 497 nfrags = 1; 498 trailer = skb; 499 tail = skb_tail_pointer(trailer); 500 501 goto skip_cow; 502 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 503 && !skb_has_frag_list(skb)) { 504 int allocsize; 505 struct sock *sk = skb->sk; 506 struct page_frag *pfrag = &x->xfrag; 507 508 esp->inplace = false; 509 510 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 511 512 spin_lock_bh(&x->lock); 513 514 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 515 spin_unlock_bh(&x->lock); 516 goto cow; 517 } 518 519 page = pfrag->page; 520 get_page(page); 521 522 vaddr = kmap_atomic(page); 523 524 tail = vaddr + pfrag->offset; 525 526 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 527 528 kunmap_atomic(vaddr); 529 530 nfrags = skb_shinfo(skb)->nr_frags; 531 532 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 533 tailen); 534 skb_shinfo(skb)->nr_frags = ++nfrags; 535 536 pfrag->offset = pfrag->offset + allocsize; 537 538 spin_unlock_bh(&x->lock); 539 540 nfrags++; 541 542 skb->len += tailen; 543 skb->data_len += tailen; 544 skb->truesize += tailen; 545 if (sk && sk_fullsock(sk)) 546 refcount_add(tailen, &sk->sk_wmem_alloc); 547 548 goto out; 549 } 550 } 551 552 cow: 553 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 554 555 nfrags = skb_cow_data(skb, tailen, &trailer); 556 if (nfrags < 0) 557 goto out; 558 tail = skb_tail_pointer(trailer); 559 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 560 561 skip_cow: 562 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 563 pskb_put(skb, trailer, tailen); 564 565 out: 566 return nfrags; 567 } 568 EXPORT_SYMBOL_GPL(esp6_output_head); 569 570 int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 571 { 572 u8 *iv; 573 int alen; 574 void *tmp; 575 int ivlen; 576 int assoclen; 577 int extralen; 578 struct page *page; 579 struct ip_esp_hdr *esph; 580 struct aead_request *req; 581 struct crypto_aead *aead; 582 struct scatterlist *sg, *dsg; 583 struct esp_output_extra *extra; 584 int err = -ENOMEM; 585 586 assoclen = sizeof(struct ip_esp_hdr); 587 extralen = 0; 588 589 if (x->props.flags & XFRM_STATE_ESN) { 590 extralen += sizeof(*extra); 591 assoclen += sizeof(__be32); 592 } 593 594 aead = x->data; 595 alen = crypto_aead_authsize(aead); 596 ivlen = crypto_aead_ivsize(aead); 597 598 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 599 if (!tmp) 600 goto error; 601 602 extra = esp_tmp_extra(tmp); 603 iv = esp_tmp_iv(aead, tmp, extralen); 604 req = esp_tmp_req(aead, iv); 605 sg = esp_req_sg(aead, req); 606 607 if (esp->inplace) 608 dsg = sg; 609 else 610 dsg = &sg[esp->nfrags]; 611 612 esph = esp_output_set_esn(skb, x, esp->esph, extra); 613 esp->esph = esph; 614 615 sg_init_table(sg, esp->nfrags); 616 err = skb_to_sgvec(skb, sg, 617 (unsigned char *)esph - skb->data, 618 assoclen + ivlen + esp->clen + alen); 619 if (unlikely(err < 0)) 620 goto error_free; 621 622 if (!esp->inplace) { 623 int allocsize; 624 struct page_frag *pfrag = &x->xfrag; 625 626 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 627 628 spin_lock_bh(&x->lock); 629 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 630 spin_unlock_bh(&x->lock); 631 goto error_free; 632 } 633 634 skb_shinfo(skb)->nr_frags = 1; 635 636 page = pfrag->page; 637 get_page(page); 638 /* replace page frags in skb with new page */ 639 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 640 pfrag->offset = pfrag->offset + allocsize; 641 spin_unlock_bh(&x->lock); 642 643 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 644 err = skb_to_sgvec(skb, dsg, 645 (unsigned char *)esph - skb->data, 646 assoclen + ivlen + esp->clen + alen); 647 if (unlikely(err < 0)) 648 goto error_free; 649 } 650 651 if ((x->props.flags & XFRM_STATE_ESN)) 652 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 653 else 654 aead_request_set_callback(req, 0, esp_output_done, skb); 655 656 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 657 aead_request_set_ad(req, assoclen); 658 659 memset(iv, 0, ivlen); 660 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 661 min(ivlen, 8)); 662 663 ESP_SKB_CB(skb)->tmp = tmp; 664 err = crypto_aead_encrypt(req); 665 666 switch (err) { 667 case -EINPROGRESS: 668 goto error; 669 670 case -ENOSPC: 671 err = NET_XMIT_DROP; 672 break; 673 674 case 0: 675 if ((x->props.flags & XFRM_STATE_ESN)) 676 esp_output_restore_header(skb); 677 esp_output_encap_csum(skb); 678 } 679 680 if (sg != dsg) 681 esp_ssg_unref(x, tmp); 682 683 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 684 err = esp_output_tail_tcp(x, skb); 685 686 error_free: 687 kfree(tmp); 688 error: 689 return err; 690 } 691 EXPORT_SYMBOL_GPL(esp6_output_tail); 692 693 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) 694 { 695 int alen; 696 int blksize; 697 struct ip_esp_hdr *esph; 698 struct crypto_aead *aead; 699 struct esp_info esp; 700 701 esp.inplace = true; 702 703 esp.proto = *skb_mac_header(skb); 704 *skb_mac_header(skb) = IPPROTO_ESP; 705 706 /* skb is pure payload to encrypt */ 707 708 aead = x->data; 709 alen = crypto_aead_authsize(aead); 710 711 esp.tfclen = 0; 712 if (x->tfcpad) { 713 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 714 u32 padto; 715 716 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 717 if (skb->len < padto) 718 esp.tfclen = padto - skb->len; 719 } 720 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 721 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 722 esp.plen = esp.clen - skb->len - esp.tfclen; 723 esp.tailen = esp.tfclen + esp.plen + alen; 724 725 esp.esph = ip_esp_hdr(skb); 726 727 esp.nfrags = esp6_output_head(x, skb, &esp); 728 if (esp.nfrags < 0) 729 return esp.nfrags; 730 731 esph = esp.esph; 732 esph->spi = x->id.spi; 733 734 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 735 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 736 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 737 738 skb_push(skb, -skb_network_offset(skb)); 739 740 return esp6_output_tail(x, skb, &esp); 741 } 742 743 static inline int esp_remove_trailer(struct sk_buff *skb) 744 { 745 struct xfrm_state *x = xfrm_input_state(skb); 746 struct xfrm_offload *xo = xfrm_offload(skb); 747 struct crypto_aead *aead = x->data; 748 int alen, hlen, elen; 749 int padlen, trimlen; 750 __wsum csumdiff; 751 u8 nexthdr[2]; 752 int ret; 753 754 alen = crypto_aead_authsize(aead); 755 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 756 elen = skb->len - hlen; 757 758 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) { 759 ret = xo->proto; 760 goto out; 761 } 762 763 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2); 764 BUG_ON(ret); 765 766 ret = -EINVAL; 767 padlen = nexthdr[0]; 768 if (padlen + 2 + alen >= elen) { 769 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 770 padlen + 2, elen - alen); 771 goto out; 772 } 773 774 trimlen = alen + padlen + 2; 775 if (skb->ip_summed == CHECKSUM_COMPLETE) { 776 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 777 skb->csum = csum_block_sub(skb->csum, csumdiff, 778 skb->len - trimlen); 779 } 780 pskb_trim(skb, skb->len - trimlen); 781 782 ret = nexthdr[1]; 783 784 out: 785 return ret; 786 } 787 788 int esp6_input_done2(struct sk_buff *skb, int err) 789 { 790 struct xfrm_state *x = xfrm_input_state(skb); 791 struct xfrm_offload *xo = xfrm_offload(skb); 792 struct crypto_aead *aead = x->data; 793 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 794 int hdr_len = skb_network_header_len(skb); 795 796 if (!xo || (xo && !(xo->flags & CRYPTO_DONE))) 797 kfree(ESP_SKB_CB(skb)->tmp); 798 799 if (unlikely(err)) 800 goto out; 801 802 err = esp_remove_trailer(skb); 803 if (unlikely(err < 0)) 804 goto out; 805 806 if (x->encap) { 807 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 808 struct xfrm_encap_tmpl *encap = x->encap; 809 struct udphdr *uh = (void *)(skb_network_header(skb) + hdr_len); 810 struct tcphdr *th = (void *)(skb_network_header(skb) + hdr_len); 811 __be16 source; 812 813 switch (x->encap->encap_type) { 814 case TCP_ENCAP_ESPINTCP: 815 source = th->source; 816 break; 817 case UDP_ENCAP_ESPINUDP: 818 case UDP_ENCAP_ESPINUDP_NON_IKE: 819 source = uh->source; 820 break; 821 default: 822 WARN_ON_ONCE(1); 823 err = -EINVAL; 824 goto out; 825 } 826 827 /* 828 * 1) if the NAT-T peer's IP or port changed then 829 * advertize the change to the keying daemon. 830 * This is an inbound SA, so just compare 831 * SRC ports. 832 */ 833 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) || 834 source != encap->encap_sport) { 835 xfrm_address_t ipaddr; 836 837 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6)); 838 km_new_mapping(x, &ipaddr, source); 839 840 /* XXX: perhaps add an extra 841 * policy check here, to see 842 * if we should allow or 843 * reject a packet from a 844 * different source 845 * address/port. 846 */ 847 } 848 849 /* 850 * 2) ignore UDP/TCP checksums in case 851 * of NAT-T in Transport Mode, or 852 * perform other post-processing fixes 853 * as per draft-ietf-ipsec-udp-encaps-06, 854 * section 3.1.2 855 */ 856 if (x->props.mode == XFRM_MODE_TRANSPORT) 857 skb->ip_summed = CHECKSUM_UNNECESSARY; 858 } 859 860 skb_postpull_rcsum(skb, skb_network_header(skb), 861 skb_network_header_len(skb)); 862 skb_pull_rcsum(skb, hlen); 863 if (x->props.mode == XFRM_MODE_TUNNEL) 864 skb_reset_transport_header(skb); 865 else 866 skb_set_transport_header(skb, -hdr_len); 867 868 /* RFC4303: Drop dummy packets without any error */ 869 if (err == IPPROTO_NONE) 870 err = -EINVAL; 871 872 out: 873 return err; 874 } 875 EXPORT_SYMBOL_GPL(esp6_input_done2); 876 877 static void esp_input_done(struct crypto_async_request *base, int err) 878 { 879 struct sk_buff *skb = base->data; 880 881 xfrm_input_resume(skb, esp6_input_done2(skb, err)); 882 } 883 884 static void esp_input_restore_header(struct sk_buff *skb) 885 { 886 esp_restore_header(skb, 0); 887 __skb_pull(skb, 4); 888 } 889 890 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 891 { 892 struct xfrm_state *x = xfrm_input_state(skb); 893 894 /* For ESN we move the header forward by 4 bytes to 895 * accomodate the high bits. We will move it back after 896 * decryption. 897 */ 898 if ((x->props.flags & XFRM_STATE_ESN)) { 899 struct ip_esp_hdr *esph = skb_push(skb, 4); 900 901 *seqhi = esph->spi; 902 esph->spi = esph->seq_no; 903 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 904 } 905 } 906 907 static void esp_input_done_esn(struct crypto_async_request *base, int err) 908 { 909 struct sk_buff *skb = base->data; 910 911 esp_input_restore_header(skb); 912 esp_input_done(base, err); 913 } 914 915 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) 916 { 917 struct crypto_aead *aead = x->data; 918 struct aead_request *req; 919 struct sk_buff *trailer; 920 int ivlen = crypto_aead_ivsize(aead); 921 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 922 int nfrags; 923 int assoclen; 924 int seqhilen; 925 int ret = 0; 926 void *tmp; 927 __be32 *seqhi; 928 u8 *iv; 929 struct scatterlist *sg; 930 931 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) { 932 ret = -EINVAL; 933 goto out; 934 } 935 936 if (elen <= 0) { 937 ret = -EINVAL; 938 goto out; 939 } 940 941 assoclen = sizeof(struct ip_esp_hdr); 942 seqhilen = 0; 943 944 if (x->props.flags & XFRM_STATE_ESN) { 945 seqhilen += sizeof(__be32); 946 assoclen += seqhilen; 947 } 948 949 if (!skb_cloned(skb)) { 950 if (!skb_is_nonlinear(skb)) { 951 nfrags = 1; 952 953 goto skip_cow; 954 } else if (!skb_has_frag_list(skb)) { 955 nfrags = skb_shinfo(skb)->nr_frags; 956 nfrags++; 957 958 goto skip_cow; 959 } 960 } 961 962 nfrags = skb_cow_data(skb, 0, &trailer); 963 if (nfrags < 0) { 964 ret = -EINVAL; 965 goto out; 966 } 967 968 skip_cow: 969 ret = -ENOMEM; 970 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 971 if (!tmp) 972 goto out; 973 974 ESP_SKB_CB(skb)->tmp = tmp; 975 seqhi = esp_tmp_extra(tmp); 976 iv = esp_tmp_iv(aead, tmp, seqhilen); 977 req = esp_tmp_req(aead, iv); 978 sg = esp_req_sg(aead, req); 979 980 esp_input_set_header(skb, seqhi); 981 982 sg_init_table(sg, nfrags); 983 ret = skb_to_sgvec(skb, sg, 0, skb->len); 984 if (unlikely(ret < 0)) { 985 kfree(tmp); 986 goto out; 987 } 988 989 skb->ip_summed = CHECKSUM_NONE; 990 991 if ((x->props.flags & XFRM_STATE_ESN)) 992 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 993 else 994 aead_request_set_callback(req, 0, esp_input_done, skb); 995 996 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 997 aead_request_set_ad(req, assoclen); 998 999 ret = crypto_aead_decrypt(req); 1000 if (ret == -EINPROGRESS) 1001 goto out; 1002 1003 if ((x->props.flags & XFRM_STATE_ESN)) 1004 esp_input_restore_header(skb); 1005 1006 ret = esp6_input_done2(skb, ret); 1007 1008 out: 1009 return ret; 1010 } 1011 1012 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 1013 u8 type, u8 code, int offset, __be32 info) 1014 { 1015 struct net *net = dev_net(skb->dev); 1016 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 1017 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset); 1018 struct xfrm_state *x; 1019 1020 if (type != ICMPV6_PKT_TOOBIG && 1021 type != NDISC_REDIRECT) 1022 return 0; 1023 1024 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 1025 esph->spi, IPPROTO_ESP, AF_INET6); 1026 if (!x) 1027 return 0; 1028 1029 if (type == NDISC_REDIRECT) 1030 ip6_redirect(skb, net, skb->dev->ifindex, 0, 1031 sock_net_uid(net, NULL)); 1032 else 1033 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 1034 xfrm_state_put(x); 1035 1036 return 0; 1037 } 1038 1039 static void esp6_destroy(struct xfrm_state *x) 1040 { 1041 struct crypto_aead *aead = x->data; 1042 1043 if (!aead) 1044 return; 1045 1046 crypto_free_aead(aead); 1047 } 1048 1049 static int esp_init_aead(struct xfrm_state *x) 1050 { 1051 char aead_name[CRYPTO_MAX_ALG_NAME]; 1052 struct crypto_aead *aead; 1053 int err; 1054 1055 err = -ENAMETOOLONG; 1056 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1057 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) 1058 goto error; 1059 1060 aead = crypto_alloc_aead(aead_name, 0, 0); 1061 err = PTR_ERR(aead); 1062 if (IS_ERR(aead)) 1063 goto error; 1064 1065 x->data = aead; 1066 1067 err = crypto_aead_setkey(aead, x->aead->alg_key, 1068 (x->aead->alg_key_len + 7) / 8); 1069 if (err) 1070 goto error; 1071 1072 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1073 if (err) 1074 goto error; 1075 1076 error: 1077 return err; 1078 } 1079 1080 static int esp_init_authenc(struct xfrm_state *x) 1081 { 1082 struct crypto_aead *aead; 1083 struct crypto_authenc_key_param *param; 1084 struct rtattr *rta; 1085 char *key; 1086 char *p; 1087 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1088 unsigned int keylen; 1089 int err; 1090 1091 err = -EINVAL; 1092 if (!x->ealg) 1093 goto error; 1094 1095 err = -ENAMETOOLONG; 1096 1097 if ((x->props.flags & XFRM_STATE_ESN)) { 1098 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1099 "%s%sauthencesn(%s,%s)%s", 1100 x->geniv ?: "", x->geniv ? "(" : "", 1101 x->aalg ? x->aalg->alg_name : "digest_null", 1102 x->ealg->alg_name, 1103 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1104 goto error; 1105 } else { 1106 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1107 "%s%sauthenc(%s,%s)%s", 1108 x->geniv ?: "", x->geniv ? "(" : "", 1109 x->aalg ? x->aalg->alg_name : "digest_null", 1110 x->ealg->alg_name, 1111 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1112 goto error; 1113 } 1114 1115 aead = crypto_alloc_aead(authenc_name, 0, 0); 1116 err = PTR_ERR(aead); 1117 if (IS_ERR(aead)) 1118 goto error; 1119 1120 x->data = aead; 1121 1122 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1123 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1124 err = -ENOMEM; 1125 key = kmalloc(keylen, GFP_KERNEL); 1126 if (!key) 1127 goto error; 1128 1129 p = key; 1130 rta = (void *)p; 1131 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1132 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1133 param = RTA_DATA(rta); 1134 p += RTA_SPACE(sizeof(*param)); 1135 1136 if (x->aalg) { 1137 struct xfrm_algo_desc *aalg_desc; 1138 1139 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1140 p += (x->aalg->alg_key_len + 7) / 8; 1141 1142 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1143 BUG_ON(!aalg_desc); 1144 1145 err = -EINVAL; 1146 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1147 crypto_aead_authsize(aead)) { 1148 pr_info("ESP: %s digestsize %u != %hu\n", 1149 x->aalg->alg_name, 1150 crypto_aead_authsize(aead), 1151 aalg_desc->uinfo.auth.icv_fullbits / 8); 1152 goto free_key; 1153 } 1154 1155 err = crypto_aead_setauthsize( 1156 aead, x->aalg->alg_trunc_len / 8); 1157 if (err) 1158 goto free_key; 1159 } 1160 1161 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1162 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1163 1164 err = crypto_aead_setkey(aead, key, keylen); 1165 1166 free_key: 1167 kfree(key); 1168 1169 error: 1170 return err; 1171 } 1172 1173 static int esp6_init_state(struct xfrm_state *x) 1174 { 1175 struct crypto_aead *aead; 1176 u32 align; 1177 int err; 1178 1179 x->data = NULL; 1180 1181 if (x->aead) 1182 err = esp_init_aead(x); 1183 else 1184 err = esp_init_authenc(x); 1185 1186 if (err) 1187 goto error; 1188 1189 aead = x->data; 1190 1191 x->props.header_len = sizeof(struct ip_esp_hdr) + 1192 crypto_aead_ivsize(aead); 1193 switch (x->props.mode) { 1194 case XFRM_MODE_BEET: 1195 if (x->sel.family != AF_INET6) 1196 x->props.header_len += IPV4_BEET_PHMAXLEN + 1197 (sizeof(struct ipv6hdr) - sizeof(struct iphdr)); 1198 break; 1199 default: 1200 case XFRM_MODE_TRANSPORT: 1201 break; 1202 case XFRM_MODE_TUNNEL: 1203 x->props.header_len += sizeof(struct ipv6hdr); 1204 break; 1205 } 1206 1207 if (x->encap) { 1208 struct xfrm_encap_tmpl *encap = x->encap; 1209 1210 switch (encap->encap_type) { 1211 default: 1212 err = -EINVAL; 1213 goto error; 1214 case UDP_ENCAP_ESPINUDP: 1215 x->props.header_len += sizeof(struct udphdr); 1216 break; 1217 case UDP_ENCAP_ESPINUDP_NON_IKE: 1218 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 1219 break; 1220 #ifdef CONFIG_INET6_ESPINTCP 1221 case TCP_ENCAP_ESPINTCP: 1222 /* only the length field, TCP encap is done by 1223 * the socket 1224 */ 1225 x->props.header_len += 2; 1226 break; 1227 #endif 1228 } 1229 } 1230 1231 align = ALIGN(crypto_aead_blocksize(aead), 4); 1232 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1233 1234 error: 1235 return err; 1236 } 1237 1238 static int esp6_rcv_cb(struct sk_buff *skb, int err) 1239 { 1240 return 0; 1241 } 1242 1243 static const struct xfrm_type esp6_type = { 1244 .description = "ESP6", 1245 .owner = THIS_MODULE, 1246 .proto = IPPROTO_ESP, 1247 .flags = XFRM_TYPE_REPLAY_PROT, 1248 .init_state = esp6_init_state, 1249 .destructor = esp6_destroy, 1250 .input = esp6_input, 1251 .output = esp6_output, 1252 .hdr_offset = xfrm6_find_1stfragopt, 1253 }; 1254 1255 static struct xfrm6_protocol esp6_protocol = { 1256 .handler = xfrm6_rcv, 1257 .input_handler = xfrm_input, 1258 .cb_handler = esp6_rcv_cb, 1259 .err_handler = esp6_err, 1260 .priority = 0, 1261 }; 1262 1263 static int __init esp6_init(void) 1264 { 1265 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { 1266 pr_info("%s: can't add xfrm type\n", __func__); 1267 return -EAGAIN; 1268 } 1269 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) { 1270 pr_info("%s: can't add protocol\n", __func__); 1271 xfrm_unregister_type(&esp6_type, AF_INET6); 1272 return -EAGAIN; 1273 } 1274 1275 return 0; 1276 } 1277 1278 static void __exit esp6_fini(void) 1279 { 1280 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0) 1281 pr_info("%s: can't remove protocol\n", __func__); 1282 xfrm_unregister_type(&esp6_type, AF_INET6); 1283 } 1284 1285 module_init(esp6_init); 1286 module_exit(esp6_fini); 1287 1288 MODULE_LICENSE("GPL"); 1289 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP); 1290