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->sk, 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); 811 812 if (offset < 0) { 813 err = -EINVAL; 814 goto out; 815 } 816 817 uh = (void *)(skb->data + offset); 818 th = (void *)(skb->data + offset); 819 hdr_len += offset; 820 821 switch (x->encap->encap_type) { 822 case TCP_ENCAP_ESPINTCP: 823 source = th->source; 824 break; 825 case UDP_ENCAP_ESPINUDP: 826 case UDP_ENCAP_ESPINUDP_NON_IKE: 827 source = uh->source; 828 break; 829 default: 830 WARN_ON_ONCE(1); 831 err = -EINVAL; 832 goto out; 833 } 834 835 /* 836 * 1) if the NAT-T peer's IP or port changed then 837 * advertize the change to the keying daemon. 838 * This is an inbound SA, so just compare 839 * SRC ports. 840 */ 841 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) || 842 source != encap->encap_sport) { 843 xfrm_address_t ipaddr; 844 845 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6)); 846 km_new_mapping(x, &ipaddr, source); 847 848 /* XXX: perhaps add an extra 849 * policy check here, to see 850 * if we should allow or 851 * reject a packet from a 852 * different source 853 * address/port. 854 */ 855 } 856 857 /* 858 * 2) ignore UDP/TCP checksums in case 859 * of NAT-T in Transport Mode, or 860 * perform other post-processing fixes 861 * as per draft-ietf-ipsec-udp-encaps-06, 862 * section 3.1.2 863 */ 864 if (x->props.mode == XFRM_MODE_TRANSPORT) 865 skb->ip_summed = CHECKSUM_UNNECESSARY; 866 } 867 868 skb_postpull_rcsum(skb, skb_network_header(skb), 869 skb_network_header_len(skb)); 870 skb_pull_rcsum(skb, hlen); 871 if (x->props.mode == XFRM_MODE_TUNNEL) 872 skb_reset_transport_header(skb); 873 else 874 skb_set_transport_header(skb, -hdr_len); 875 876 /* RFC4303: Drop dummy packets without any error */ 877 if (err == IPPROTO_NONE) 878 err = -EINVAL; 879 880 out: 881 return err; 882 } 883 EXPORT_SYMBOL_GPL(esp6_input_done2); 884 885 static void esp_input_done(struct crypto_async_request *base, int err) 886 { 887 struct sk_buff *skb = base->data; 888 889 xfrm_input_resume(skb, esp6_input_done2(skb, err)); 890 } 891 892 static void esp_input_restore_header(struct sk_buff *skb) 893 { 894 esp_restore_header(skb, 0); 895 __skb_pull(skb, 4); 896 } 897 898 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 899 { 900 struct xfrm_state *x = xfrm_input_state(skb); 901 902 /* For ESN we move the header forward by 4 bytes to 903 * accomodate the high bits. We will move it back after 904 * decryption. 905 */ 906 if ((x->props.flags & XFRM_STATE_ESN)) { 907 struct ip_esp_hdr *esph = skb_push(skb, 4); 908 909 *seqhi = esph->spi; 910 esph->spi = esph->seq_no; 911 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 912 } 913 } 914 915 static void esp_input_done_esn(struct crypto_async_request *base, int err) 916 { 917 struct sk_buff *skb = base->data; 918 919 esp_input_restore_header(skb); 920 esp_input_done(base, err); 921 } 922 923 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) 924 { 925 struct crypto_aead *aead = x->data; 926 struct aead_request *req; 927 struct sk_buff *trailer; 928 int ivlen = crypto_aead_ivsize(aead); 929 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 930 int nfrags; 931 int assoclen; 932 int seqhilen; 933 int ret = 0; 934 void *tmp; 935 __be32 *seqhi; 936 u8 *iv; 937 struct scatterlist *sg; 938 939 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) { 940 ret = -EINVAL; 941 goto out; 942 } 943 944 if (elen <= 0) { 945 ret = -EINVAL; 946 goto out; 947 } 948 949 assoclen = sizeof(struct ip_esp_hdr); 950 seqhilen = 0; 951 952 if (x->props.flags & XFRM_STATE_ESN) { 953 seqhilen += sizeof(__be32); 954 assoclen += seqhilen; 955 } 956 957 if (!skb_cloned(skb)) { 958 if (!skb_is_nonlinear(skb)) { 959 nfrags = 1; 960 961 goto skip_cow; 962 } else if (!skb_has_frag_list(skb)) { 963 nfrags = skb_shinfo(skb)->nr_frags; 964 nfrags++; 965 966 goto skip_cow; 967 } 968 } 969 970 nfrags = skb_cow_data(skb, 0, &trailer); 971 if (nfrags < 0) { 972 ret = -EINVAL; 973 goto out; 974 } 975 976 skip_cow: 977 ret = -ENOMEM; 978 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 979 if (!tmp) 980 goto out; 981 982 ESP_SKB_CB(skb)->tmp = tmp; 983 seqhi = esp_tmp_extra(tmp); 984 iv = esp_tmp_iv(aead, tmp, seqhilen); 985 req = esp_tmp_req(aead, iv); 986 sg = esp_req_sg(aead, req); 987 988 esp_input_set_header(skb, seqhi); 989 990 sg_init_table(sg, nfrags); 991 ret = skb_to_sgvec(skb, sg, 0, skb->len); 992 if (unlikely(ret < 0)) { 993 kfree(tmp); 994 goto out; 995 } 996 997 skb->ip_summed = CHECKSUM_NONE; 998 999 if ((x->props.flags & XFRM_STATE_ESN)) 1000 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 1001 else 1002 aead_request_set_callback(req, 0, esp_input_done, skb); 1003 1004 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 1005 aead_request_set_ad(req, assoclen); 1006 1007 ret = crypto_aead_decrypt(req); 1008 if (ret == -EINPROGRESS) 1009 goto out; 1010 1011 if ((x->props.flags & XFRM_STATE_ESN)) 1012 esp_input_restore_header(skb); 1013 1014 ret = esp6_input_done2(skb, ret); 1015 1016 out: 1017 return ret; 1018 } 1019 1020 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 1021 u8 type, u8 code, int offset, __be32 info) 1022 { 1023 struct net *net = dev_net(skb->dev); 1024 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 1025 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset); 1026 struct xfrm_state *x; 1027 1028 if (type != ICMPV6_PKT_TOOBIG && 1029 type != NDISC_REDIRECT) 1030 return 0; 1031 1032 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 1033 esph->spi, IPPROTO_ESP, AF_INET6); 1034 if (!x) 1035 return 0; 1036 1037 if (type == NDISC_REDIRECT) 1038 ip6_redirect(skb, net, skb->dev->ifindex, 0, 1039 sock_net_uid(net, NULL)); 1040 else 1041 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 1042 xfrm_state_put(x); 1043 1044 return 0; 1045 } 1046 1047 static void esp6_destroy(struct xfrm_state *x) 1048 { 1049 struct crypto_aead *aead = x->data; 1050 1051 if (!aead) 1052 return; 1053 1054 crypto_free_aead(aead); 1055 } 1056 1057 static int esp_init_aead(struct xfrm_state *x) 1058 { 1059 char aead_name[CRYPTO_MAX_ALG_NAME]; 1060 struct crypto_aead *aead; 1061 int err; 1062 1063 err = -ENAMETOOLONG; 1064 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1065 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) 1066 goto error; 1067 1068 aead = crypto_alloc_aead(aead_name, 0, 0); 1069 err = PTR_ERR(aead); 1070 if (IS_ERR(aead)) 1071 goto error; 1072 1073 x->data = aead; 1074 1075 err = crypto_aead_setkey(aead, x->aead->alg_key, 1076 (x->aead->alg_key_len + 7) / 8); 1077 if (err) 1078 goto error; 1079 1080 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1081 if (err) 1082 goto error; 1083 1084 error: 1085 return err; 1086 } 1087 1088 static int esp_init_authenc(struct xfrm_state *x) 1089 { 1090 struct crypto_aead *aead; 1091 struct crypto_authenc_key_param *param; 1092 struct rtattr *rta; 1093 char *key; 1094 char *p; 1095 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1096 unsigned int keylen; 1097 int err; 1098 1099 err = -EINVAL; 1100 if (!x->ealg) 1101 goto error; 1102 1103 err = -ENAMETOOLONG; 1104 1105 if ((x->props.flags & XFRM_STATE_ESN)) { 1106 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1107 "%s%sauthencesn(%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 } else { 1114 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1115 "%s%sauthenc(%s,%s)%s", 1116 x->geniv ?: "", x->geniv ? "(" : "", 1117 x->aalg ? x->aalg->alg_name : "digest_null", 1118 x->ealg->alg_name, 1119 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1120 goto error; 1121 } 1122 1123 aead = crypto_alloc_aead(authenc_name, 0, 0); 1124 err = PTR_ERR(aead); 1125 if (IS_ERR(aead)) 1126 goto error; 1127 1128 x->data = aead; 1129 1130 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1131 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1132 err = -ENOMEM; 1133 key = kmalloc(keylen, GFP_KERNEL); 1134 if (!key) 1135 goto error; 1136 1137 p = key; 1138 rta = (void *)p; 1139 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1140 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1141 param = RTA_DATA(rta); 1142 p += RTA_SPACE(sizeof(*param)); 1143 1144 if (x->aalg) { 1145 struct xfrm_algo_desc *aalg_desc; 1146 1147 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1148 p += (x->aalg->alg_key_len + 7) / 8; 1149 1150 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1151 BUG_ON(!aalg_desc); 1152 1153 err = -EINVAL; 1154 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1155 crypto_aead_authsize(aead)) { 1156 pr_info("ESP: %s digestsize %u != %u\n", 1157 x->aalg->alg_name, 1158 crypto_aead_authsize(aead), 1159 aalg_desc->uinfo.auth.icv_fullbits / 8); 1160 goto free_key; 1161 } 1162 1163 err = crypto_aead_setauthsize( 1164 aead, x->aalg->alg_trunc_len / 8); 1165 if (err) 1166 goto free_key; 1167 } 1168 1169 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1170 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1171 1172 err = crypto_aead_setkey(aead, key, keylen); 1173 1174 free_key: 1175 kfree(key); 1176 1177 error: 1178 return err; 1179 } 1180 1181 static int esp6_init_state(struct xfrm_state *x) 1182 { 1183 struct crypto_aead *aead; 1184 u32 align; 1185 int err; 1186 1187 x->data = NULL; 1188 1189 if (x->aead) 1190 err = esp_init_aead(x); 1191 else 1192 err = esp_init_authenc(x); 1193 1194 if (err) 1195 goto error; 1196 1197 aead = x->data; 1198 1199 x->props.header_len = sizeof(struct ip_esp_hdr) + 1200 crypto_aead_ivsize(aead); 1201 switch (x->props.mode) { 1202 case XFRM_MODE_BEET: 1203 if (x->sel.family != AF_INET6) 1204 x->props.header_len += IPV4_BEET_PHMAXLEN + 1205 (sizeof(struct ipv6hdr) - sizeof(struct iphdr)); 1206 break; 1207 default: 1208 case XFRM_MODE_TRANSPORT: 1209 break; 1210 case XFRM_MODE_TUNNEL: 1211 x->props.header_len += sizeof(struct ipv6hdr); 1212 break; 1213 } 1214 1215 if (x->encap) { 1216 struct xfrm_encap_tmpl *encap = x->encap; 1217 1218 switch (encap->encap_type) { 1219 default: 1220 err = -EINVAL; 1221 goto error; 1222 case UDP_ENCAP_ESPINUDP: 1223 x->props.header_len += sizeof(struct udphdr); 1224 break; 1225 case UDP_ENCAP_ESPINUDP_NON_IKE: 1226 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 1227 break; 1228 #ifdef CONFIG_INET6_ESPINTCP 1229 case TCP_ENCAP_ESPINTCP: 1230 /* only the length field, TCP encap is done by 1231 * the socket 1232 */ 1233 x->props.header_len += 2; 1234 break; 1235 #endif 1236 } 1237 } 1238 1239 align = ALIGN(crypto_aead_blocksize(aead), 4); 1240 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1241 1242 error: 1243 return err; 1244 } 1245 1246 static int esp6_rcv_cb(struct sk_buff *skb, int err) 1247 { 1248 return 0; 1249 } 1250 1251 static const struct xfrm_type esp6_type = { 1252 .owner = THIS_MODULE, 1253 .proto = IPPROTO_ESP, 1254 .flags = XFRM_TYPE_REPLAY_PROT, 1255 .init_state = esp6_init_state, 1256 .destructor = esp6_destroy, 1257 .input = esp6_input, 1258 .output = esp6_output, 1259 }; 1260 1261 static struct xfrm6_protocol esp6_protocol = { 1262 .handler = xfrm6_rcv, 1263 .input_handler = xfrm_input, 1264 .cb_handler = esp6_rcv_cb, 1265 .err_handler = esp6_err, 1266 .priority = 0, 1267 }; 1268 1269 static int __init esp6_init(void) 1270 { 1271 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { 1272 pr_info("%s: can't add xfrm type\n", __func__); 1273 return -EAGAIN; 1274 } 1275 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) { 1276 pr_info("%s: can't add protocol\n", __func__); 1277 xfrm_unregister_type(&esp6_type, AF_INET6); 1278 return -EAGAIN; 1279 } 1280 1281 return 0; 1282 } 1283 1284 static void __exit esp6_fini(void) 1285 { 1286 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0) 1287 pr_info("%s: can't remove protocol\n", __func__); 1288 xfrm_unregister_type(&esp6_type, AF_INET6); 1289 } 1290 1291 module_init(esp6_init); 1292 module_exit(esp6_fini); 1293 1294 MODULE_LICENSE("GPL"); 1295 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP); 1296