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 #include <linux/skbuff_ref.h> 40 41 #include <linux/highmem.h> 42 43 struct esp_skb_cb { 44 struct xfrm_skb_cb xfrm; 45 void *tmp; 46 }; 47 48 struct esp_output_extra { 49 __be32 seqhi; 50 u32 esphoff; 51 }; 52 53 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0])) 54 55 /* 56 * Allocate an AEAD request structure with extra space for SG and IV. 57 * 58 * For alignment considerations the upper 32 bits of the sequence number are 59 * placed at the front, if present. Followed by the IV, the request and finally 60 * the SG list. 61 * 62 * TODO: Use spare space in skb for this where possible. 63 */ 64 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen) 65 { 66 unsigned int len; 67 68 len = seqihlen; 69 70 len += crypto_aead_ivsize(aead); 71 72 if (len) { 73 len += crypto_aead_alignmask(aead) & 74 ~(crypto_tfm_ctx_alignment() - 1); 75 len = ALIGN(len, crypto_tfm_ctx_alignment()); 76 } 77 78 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead); 79 len = ALIGN(len, __alignof__(struct scatterlist)); 80 81 len += sizeof(struct scatterlist) * nfrags; 82 83 return kmalloc(len, GFP_ATOMIC); 84 } 85 86 static inline void *esp_tmp_extra(void *tmp) 87 { 88 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra)); 89 } 90 91 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen) 92 { 93 return crypto_aead_ivsize(aead) ? 94 PTR_ALIGN((u8 *)tmp + seqhilen, 95 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen; 96 } 97 98 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv) 99 { 100 struct aead_request *req; 101 102 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead), 103 crypto_tfm_ctx_alignment()); 104 aead_request_set_tfm(req, aead); 105 return req; 106 } 107 108 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead, 109 struct aead_request *req) 110 { 111 return (void *)ALIGN((unsigned long)(req + 1) + 112 crypto_aead_reqsize(aead), 113 __alignof__(struct scatterlist)); 114 } 115 116 static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb) 117 { 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(struct esp_output_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 skb_page_unref(page_to_netmem(sg_page(sg)), 136 skb->pp_recycle); 137 } 138 139 #ifdef CONFIG_INET6_ESPINTCP 140 static struct sock *esp6_find_tcp_sk(struct xfrm_state *x) 141 { 142 struct xfrm_encap_tmpl *encap = x->encap; 143 struct net *net = xs_net(x); 144 __be16 sport, dport; 145 struct sock *sk; 146 147 spin_lock_bh(&x->lock); 148 sport = encap->encap_sport; 149 dport = encap->encap_dport; 150 spin_unlock_bh(&x->lock); 151 152 sk = __inet6_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, &x->id.daddr.in6, 153 dport, &x->props.saddr.in6, ntohs(sport), 0, 0); 154 if (!sk) 155 return ERR_PTR(-ENOENT); 156 157 if (!tcp_is_ulp_esp(sk)) { 158 sock_put(sk); 159 return ERR_PTR(-EINVAL); 160 } 161 162 return sk; 163 } 164 165 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) 166 { 167 struct sock *sk; 168 int err; 169 170 rcu_read_lock(); 171 172 sk = esp6_find_tcp_sk(x); 173 err = PTR_ERR_OR_ZERO(sk); 174 if (err) { 175 kfree_skb(skb); 176 goto out; 177 } 178 179 bh_lock_sock(sk); 180 if (sock_owned_by_user(sk)) 181 err = espintcp_queue_out(sk, skb); 182 else 183 err = espintcp_push_skb(sk, skb); 184 bh_unlock_sock(sk); 185 186 sock_put(sk); 187 188 out: 189 rcu_read_unlock(); 190 return err; 191 } 192 193 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk, 194 struct sk_buff *skb) 195 { 196 struct dst_entry *dst = skb_dst(skb); 197 struct xfrm_state *x = dst->xfrm; 198 199 return esp_output_tcp_finish(x, skb); 200 } 201 202 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 203 { 204 int err; 205 206 local_bh_disable(); 207 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb); 208 local_bh_enable(); 209 210 /* EINPROGRESS just happens to do the right thing. It 211 * actually means that the skb has been consumed and 212 * isn't coming back. 213 */ 214 return err ?: -EINPROGRESS; 215 } 216 #else 217 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 218 { 219 WARN_ON(1); 220 return -EOPNOTSUPP; 221 } 222 #endif 223 224 static void esp_output_encap_csum(struct sk_buff *skb) 225 { 226 /* UDP encap with IPv6 requires a valid checksum */ 227 if (*skb_mac_header(skb) == IPPROTO_UDP) { 228 struct udphdr *uh = udp_hdr(skb); 229 struct ipv6hdr *ip6h = ipv6_hdr(skb); 230 int len = ntohs(uh->len); 231 unsigned int offset = skb_transport_offset(skb); 232 __wsum csum = skb_checksum(skb, offset, skb->len - offset, 0); 233 234 uh->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, 235 len, IPPROTO_UDP, csum); 236 if (uh->check == 0) 237 uh->check = CSUM_MANGLED_0; 238 } 239 } 240 241 static void esp_output_done(void *data, int err) 242 { 243 struct sk_buff *skb = data; 244 struct xfrm_offload *xo = xfrm_offload(skb); 245 void *tmp; 246 struct xfrm_state *x; 247 248 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 249 struct sec_path *sp = skb_sec_path(skb); 250 251 x = sp->xvec[sp->len - 1]; 252 } else { 253 x = skb_dst(skb)->xfrm; 254 } 255 256 tmp = ESP_SKB_CB(skb)->tmp; 257 esp_ssg_unref(x, tmp, skb); 258 kfree(tmp); 259 260 esp_output_encap_csum(skb); 261 262 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 263 if (err) { 264 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR); 265 kfree_skb(skb); 266 return; 267 } 268 269 skb_push(skb, skb->data - skb_mac_header(skb)); 270 secpath_reset(skb); 271 xfrm_dev_resume(skb); 272 } else { 273 if (!err && 274 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 275 esp_output_tail_tcp(x, skb); 276 else 277 xfrm_output_resume(skb_to_full_sk(skb), skb, err); 278 } 279 } 280 281 /* Move ESP header back into place. */ 282 static void esp_restore_header(struct sk_buff *skb, unsigned int offset) 283 { 284 struct ip_esp_hdr *esph = (void *)(skb->data + offset); 285 void *tmp = ESP_SKB_CB(skb)->tmp; 286 __be32 *seqhi = esp_tmp_extra(tmp); 287 288 esph->seq_no = esph->spi; 289 esph->spi = *seqhi; 290 } 291 292 static void esp_output_restore_header(struct sk_buff *skb) 293 { 294 void *tmp = ESP_SKB_CB(skb)->tmp; 295 struct esp_output_extra *extra = esp_tmp_extra(tmp); 296 297 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff - 298 sizeof(__be32)); 299 } 300 301 static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb, 302 struct xfrm_state *x, 303 struct ip_esp_hdr *esph, 304 struct esp_output_extra *extra) 305 { 306 /* For ESN we move the header forward by 4 bytes to 307 * accommodate the high bits. We will move it back after 308 * encryption. 309 */ 310 if ((x->props.flags & XFRM_STATE_ESN)) { 311 __u32 seqhi; 312 struct xfrm_offload *xo = xfrm_offload(skb); 313 314 if (xo) 315 seqhi = xo->seq.hi; 316 else 317 seqhi = XFRM_SKB_CB(skb)->seq.output.hi; 318 319 extra->esphoff = (unsigned char *)esph - 320 skb_transport_header(skb); 321 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4); 322 extra->seqhi = esph->spi; 323 esph->seq_no = htonl(seqhi); 324 } 325 326 esph->spi = x->id.spi; 327 328 return esph; 329 } 330 331 static void esp_output_done_esn(void *data, int err) 332 { 333 struct sk_buff *skb = data; 334 335 esp_output_restore_header(skb); 336 esp_output_done(data, err); 337 } 338 339 static struct ip_esp_hdr *esp6_output_udp_encap(struct sk_buff *skb, 340 int encap_type, 341 struct esp_info *esp, 342 __be16 sport, 343 __be16 dport) 344 { 345 struct udphdr *uh; 346 unsigned int len; 347 348 len = skb->len + esp->tailen - skb_transport_offset(skb); 349 if (len > U16_MAX) 350 return ERR_PTR(-EMSGSIZE); 351 352 uh = (struct udphdr *)esp->esph; 353 uh->source = sport; 354 uh->dest = dport; 355 uh->len = htons(len); 356 uh->check = 0; 357 358 *skb_mac_header(skb) = IPPROTO_UDP; 359 360 return (struct ip_esp_hdr *)(uh + 1); 361 } 362 363 #ifdef CONFIG_INET6_ESPINTCP 364 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x, 365 struct sk_buff *skb, 366 struct esp_info *esp) 367 { 368 __be16 *lenp = (void *)esp->esph; 369 struct ip_esp_hdr *esph; 370 unsigned int len; 371 struct sock *sk; 372 373 len = skb->len + esp->tailen - skb_transport_offset(skb); 374 if (len > IP_MAX_MTU) 375 return ERR_PTR(-EMSGSIZE); 376 377 rcu_read_lock(); 378 sk = esp6_find_tcp_sk(x); 379 rcu_read_unlock(); 380 381 if (IS_ERR(sk)) 382 return ERR_CAST(sk); 383 384 sock_put(sk); 385 386 *lenp = htons(len); 387 esph = (struct ip_esp_hdr *)(lenp + 1); 388 389 return esph; 390 } 391 #else 392 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x, 393 struct sk_buff *skb, 394 struct esp_info *esp) 395 { 396 return ERR_PTR(-EOPNOTSUPP); 397 } 398 #endif 399 400 static int esp6_output_encap(struct xfrm_state *x, struct sk_buff *skb, 401 struct esp_info *esp) 402 { 403 struct xfrm_encap_tmpl *encap = x->encap; 404 struct ip_esp_hdr *esph; 405 __be16 sport, dport; 406 int encap_type; 407 408 spin_lock_bh(&x->lock); 409 sport = encap->encap_sport; 410 dport = encap->encap_dport; 411 encap_type = encap->encap_type; 412 spin_unlock_bh(&x->lock); 413 414 switch (encap_type) { 415 default: 416 case UDP_ENCAP_ESPINUDP: 417 esph = esp6_output_udp_encap(skb, encap_type, esp, sport, dport); 418 break; 419 case TCP_ENCAP_ESPINTCP: 420 esph = esp6_output_tcp_encap(x, skb, esp); 421 break; 422 } 423 424 if (IS_ERR(esph)) 425 return PTR_ERR(esph); 426 427 esp->esph = esph; 428 429 return 0; 430 } 431 432 int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 433 { 434 u8 *tail; 435 int nfrags; 436 int esph_offset; 437 struct page *page; 438 struct sk_buff *trailer; 439 int tailen = esp->tailen; 440 441 if (x->encap) { 442 int err = esp6_output_encap(x, skb, esp); 443 444 if (err < 0) 445 return err; 446 } 447 448 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE || 449 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE) 450 goto cow; 451 452 if (!skb_cloned(skb)) { 453 if (tailen <= skb_tailroom(skb)) { 454 nfrags = 1; 455 trailer = skb; 456 tail = skb_tail_pointer(trailer); 457 458 goto skip_cow; 459 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 460 && !skb_has_frag_list(skb)) { 461 int allocsize; 462 struct sock *sk = skb->sk; 463 struct page_frag *pfrag = &x->xfrag; 464 465 esp->inplace = false; 466 467 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 468 469 spin_lock_bh(&x->lock); 470 471 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 472 spin_unlock_bh(&x->lock); 473 goto cow; 474 } 475 476 page = pfrag->page; 477 get_page(page); 478 479 tail = page_address(page) + pfrag->offset; 480 481 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 482 483 nfrags = skb_shinfo(skb)->nr_frags; 484 485 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 486 tailen); 487 skb_shinfo(skb)->nr_frags = ++nfrags; 488 489 pfrag->offset = pfrag->offset + allocsize; 490 491 spin_unlock_bh(&x->lock); 492 493 nfrags++; 494 495 skb->len += tailen; 496 skb->data_len += tailen; 497 skb->truesize += tailen; 498 if (sk && sk_fullsock(sk)) 499 refcount_add(tailen, &sk->sk_wmem_alloc); 500 501 goto out; 502 } 503 } 504 505 cow: 506 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 507 508 nfrags = skb_cow_data(skb, tailen, &trailer); 509 if (nfrags < 0) 510 goto out; 511 tail = skb_tail_pointer(trailer); 512 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 513 514 skip_cow: 515 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 516 pskb_put(skb, trailer, tailen); 517 518 out: 519 return nfrags; 520 } 521 EXPORT_SYMBOL_GPL(esp6_output_head); 522 523 int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 524 { 525 u8 *iv; 526 int alen; 527 void *tmp; 528 int ivlen; 529 int assoclen; 530 int extralen; 531 struct page *page; 532 struct ip_esp_hdr *esph; 533 struct aead_request *req; 534 struct crypto_aead *aead; 535 struct scatterlist *sg, *dsg; 536 struct esp_output_extra *extra; 537 int err = -ENOMEM; 538 539 assoclen = sizeof(struct ip_esp_hdr); 540 extralen = 0; 541 542 if (x->props.flags & XFRM_STATE_ESN) { 543 extralen += sizeof(*extra); 544 assoclen += sizeof(__be32); 545 } 546 547 aead = x->data; 548 alen = crypto_aead_authsize(aead); 549 ivlen = crypto_aead_ivsize(aead); 550 551 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 552 if (!tmp) 553 goto error; 554 555 extra = esp_tmp_extra(tmp); 556 iv = esp_tmp_iv(aead, tmp, extralen); 557 req = esp_tmp_req(aead, iv); 558 sg = esp_req_sg(aead, req); 559 560 if (esp->inplace) 561 dsg = sg; 562 else 563 dsg = &sg[esp->nfrags]; 564 565 esph = esp_output_set_esn(skb, x, esp->esph, extra); 566 esp->esph = esph; 567 568 sg_init_table(sg, esp->nfrags); 569 err = skb_to_sgvec(skb, sg, 570 (unsigned char *)esph - skb->data, 571 assoclen + ivlen + esp->clen + alen); 572 if (unlikely(err < 0)) 573 goto error_free; 574 575 if (!esp->inplace) { 576 int allocsize; 577 struct page_frag *pfrag = &x->xfrag; 578 579 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 580 581 spin_lock_bh(&x->lock); 582 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 583 spin_unlock_bh(&x->lock); 584 goto error_free; 585 } 586 587 skb_shinfo(skb)->nr_frags = 1; 588 589 page = pfrag->page; 590 get_page(page); 591 /* replace page frags in skb with new page */ 592 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 593 pfrag->offset = pfrag->offset + allocsize; 594 spin_unlock_bh(&x->lock); 595 596 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 597 err = skb_to_sgvec(skb, dsg, 598 (unsigned char *)esph - skb->data, 599 assoclen + ivlen + esp->clen + alen); 600 if (unlikely(err < 0)) 601 goto error_free; 602 } 603 604 if ((x->props.flags & XFRM_STATE_ESN)) 605 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 606 else 607 aead_request_set_callback(req, 0, esp_output_done, skb); 608 609 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 610 aead_request_set_ad(req, assoclen); 611 612 memset(iv, 0, ivlen); 613 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 614 min(ivlen, 8)); 615 616 ESP_SKB_CB(skb)->tmp = tmp; 617 err = crypto_aead_encrypt(req); 618 619 switch (err) { 620 case -EINPROGRESS: 621 goto error; 622 623 case -ENOSPC: 624 err = NET_XMIT_DROP; 625 break; 626 627 case 0: 628 if ((x->props.flags & XFRM_STATE_ESN)) 629 esp_output_restore_header(skb); 630 esp_output_encap_csum(skb); 631 } 632 633 if (sg != dsg) 634 esp_ssg_unref(x, tmp, skb); 635 636 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 637 err = esp_output_tail_tcp(x, skb); 638 639 error_free: 640 kfree(tmp); 641 error: 642 return err; 643 } 644 EXPORT_SYMBOL_GPL(esp6_output_tail); 645 646 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) 647 { 648 int alen; 649 int blksize; 650 struct ip_esp_hdr *esph; 651 struct crypto_aead *aead; 652 struct esp_info esp; 653 654 esp.inplace = true; 655 656 esp.proto = *skb_mac_header(skb); 657 *skb_mac_header(skb) = IPPROTO_ESP; 658 659 /* skb is pure payload to encrypt */ 660 661 aead = x->data; 662 alen = crypto_aead_authsize(aead); 663 664 esp.tfclen = 0; 665 if (x->tfcpad) { 666 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 667 u32 padto; 668 669 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 670 if (skb->len < padto) 671 esp.tfclen = padto - skb->len; 672 } 673 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 674 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 675 esp.plen = esp.clen - skb->len - esp.tfclen; 676 esp.tailen = esp.tfclen + esp.plen + alen; 677 678 esp.esph = ip_esp_hdr(skb); 679 680 esp.nfrags = esp6_output_head(x, skb, &esp); 681 if (esp.nfrags < 0) 682 return esp.nfrags; 683 684 esph = esp.esph; 685 esph->spi = x->id.spi; 686 687 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 688 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 689 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 690 691 skb_push(skb, -skb_network_offset(skb)); 692 693 return esp6_output_tail(x, skb, &esp); 694 } 695 696 static inline int esp_remove_trailer(struct sk_buff *skb) 697 { 698 struct xfrm_state *x = xfrm_input_state(skb); 699 struct crypto_aead *aead = x->data; 700 int alen, hlen, elen; 701 int padlen, trimlen; 702 __wsum csumdiff; 703 u8 nexthdr[2]; 704 int ret; 705 706 alen = crypto_aead_authsize(aead); 707 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 708 elen = skb->len - hlen; 709 710 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2); 711 BUG_ON(ret); 712 713 ret = -EINVAL; 714 padlen = nexthdr[0]; 715 if (padlen + 2 + alen >= elen) { 716 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 717 padlen + 2, elen - alen); 718 goto out; 719 } 720 721 trimlen = alen + padlen + 2; 722 if (skb->ip_summed == CHECKSUM_COMPLETE) { 723 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 724 skb->csum = csum_block_sub(skb->csum, csumdiff, 725 skb->len - trimlen); 726 } 727 ret = pskb_trim(skb, skb->len - trimlen); 728 if (unlikely(ret)) 729 return ret; 730 731 ret = nexthdr[1]; 732 733 out: 734 return ret; 735 } 736 737 int esp6_input_done2(struct sk_buff *skb, int err) 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 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 743 int hdr_len = skb_network_header_len(skb); 744 745 if (!xo || !(xo->flags & CRYPTO_DONE)) 746 kfree(ESP_SKB_CB(skb)->tmp); 747 748 if (unlikely(err)) 749 goto out; 750 751 err = esp_remove_trailer(skb); 752 if (unlikely(err < 0)) 753 goto out; 754 755 if (x->encap) { 756 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 757 int offset = skb_network_offset(skb) + sizeof(*ip6h); 758 struct xfrm_encap_tmpl *encap = x->encap; 759 u8 nexthdr = ip6h->nexthdr; 760 __be16 frag_off, source; 761 struct udphdr *uh; 762 struct tcphdr *th; 763 764 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); 765 if (offset == -1) { 766 err = -EINVAL; 767 goto out; 768 } 769 770 uh = (void *)(skb->data + offset); 771 th = (void *)(skb->data + offset); 772 hdr_len += offset; 773 774 switch (x->encap->encap_type) { 775 case TCP_ENCAP_ESPINTCP: 776 source = th->source; 777 break; 778 case UDP_ENCAP_ESPINUDP: 779 source = uh->source; 780 break; 781 default: 782 WARN_ON_ONCE(1); 783 err = -EINVAL; 784 goto out; 785 } 786 787 /* 788 * 1) if the NAT-T peer's IP or port changed then 789 * advertise the change to the keying daemon. 790 * This is an inbound SA, so just compare 791 * SRC ports. 792 */ 793 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) || 794 source != encap->encap_sport) { 795 xfrm_address_t ipaddr; 796 797 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6)); 798 km_new_mapping(x, &ipaddr, source); 799 800 /* XXX: perhaps add an extra 801 * policy check here, to see 802 * if we should allow or 803 * reject a packet from a 804 * different source 805 * address/port. 806 */ 807 } 808 809 /* 810 * 2) ignore UDP/TCP checksums in case 811 * of NAT-T in Transport Mode, or 812 * perform other post-processing fixes 813 * as per draft-ietf-ipsec-udp-encaps-06, 814 * section 3.1.2 815 */ 816 if (x->props.mode == XFRM_MODE_TRANSPORT) 817 skb->ip_summed = CHECKSUM_UNNECESSARY; 818 } 819 820 skb_postpull_rcsum(skb, skb_network_header(skb), 821 skb_network_header_len(skb)); 822 skb_pull_rcsum(skb, hlen); 823 if (x->props.mode == XFRM_MODE_TUNNEL || 824 x->props.mode == XFRM_MODE_IPTFS) 825 skb_reset_transport_header(skb); 826 else 827 skb_set_transport_header(skb, -hdr_len); 828 829 /* RFC4303: Drop dummy packets without any error */ 830 if (err == IPPROTO_NONE) 831 err = -EINVAL; 832 833 out: 834 return err; 835 } 836 EXPORT_SYMBOL_GPL(esp6_input_done2); 837 838 static void esp_input_done(void *data, int err) 839 { 840 struct sk_buff *skb = data; 841 842 xfrm_input_resume(skb, esp6_input_done2(skb, err)); 843 } 844 845 static void esp_input_restore_header(struct sk_buff *skb) 846 { 847 esp_restore_header(skb, 0); 848 __skb_pull(skb, 4); 849 } 850 851 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 852 { 853 struct xfrm_state *x = xfrm_input_state(skb); 854 855 /* For ESN we move the header forward by 4 bytes to 856 * accommodate the high bits. We will move it back after 857 * decryption. 858 */ 859 if ((x->props.flags & XFRM_STATE_ESN)) { 860 struct ip_esp_hdr *esph = skb_push(skb, 4); 861 862 *seqhi = esph->spi; 863 esph->spi = esph->seq_no; 864 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 865 } 866 } 867 868 static void esp_input_done_esn(void *data, int err) 869 { 870 struct sk_buff *skb = data; 871 872 esp_input_restore_header(skb); 873 esp_input_done(data, err); 874 } 875 876 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) 877 { 878 struct crypto_aead *aead = x->data; 879 struct aead_request *req; 880 struct sk_buff *trailer; 881 int ivlen = crypto_aead_ivsize(aead); 882 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 883 int nfrags; 884 int assoclen; 885 int seqhilen; 886 int ret = 0; 887 void *tmp; 888 __be32 *seqhi; 889 u8 *iv; 890 struct scatterlist *sg; 891 892 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) { 893 ret = -EINVAL; 894 goto out; 895 } 896 897 if (elen <= 0) { 898 ret = -EINVAL; 899 goto out; 900 } 901 902 assoclen = sizeof(struct ip_esp_hdr); 903 seqhilen = 0; 904 905 if (x->props.flags & XFRM_STATE_ESN) { 906 seqhilen += sizeof(__be32); 907 assoclen += seqhilen; 908 } 909 910 if (!skb_cloned(skb)) { 911 if (!skb_is_nonlinear(skb)) { 912 nfrags = 1; 913 914 goto skip_cow; 915 } else if (!skb_has_frag_list(skb)) { 916 nfrags = skb_shinfo(skb)->nr_frags; 917 nfrags++; 918 919 goto skip_cow; 920 } 921 } 922 923 nfrags = skb_cow_data(skb, 0, &trailer); 924 if (nfrags < 0) { 925 ret = -EINVAL; 926 goto out; 927 } 928 929 skip_cow: 930 ret = -ENOMEM; 931 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 932 if (!tmp) 933 goto out; 934 935 ESP_SKB_CB(skb)->tmp = tmp; 936 seqhi = esp_tmp_extra(tmp); 937 iv = esp_tmp_iv(aead, tmp, seqhilen); 938 req = esp_tmp_req(aead, iv); 939 sg = esp_req_sg(aead, req); 940 941 esp_input_set_header(skb, seqhi); 942 943 sg_init_table(sg, nfrags); 944 ret = skb_to_sgvec(skb, sg, 0, skb->len); 945 if (unlikely(ret < 0)) { 946 kfree(tmp); 947 goto out; 948 } 949 950 skb->ip_summed = CHECKSUM_NONE; 951 952 if ((x->props.flags & XFRM_STATE_ESN)) 953 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 954 else 955 aead_request_set_callback(req, 0, esp_input_done, skb); 956 957 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 958 aead_request_set_ad(req, assoclen); 959 960 ret = crypto_aead_decrypt(req); 961 if (ret == -EINPROGRESS) 962 goto out; 963 964 if ((x->props.flags & XFRM_STATE_ESN)) 965 esp_input_restore_header(skb); 966 967 ret = esp6_input_done2(skb, ret); 968 969 out: 970 return ret; 971 } 972 973 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 974 u8 type, u8 code, int offset, __be32 info) 975 { 976 struct net *net = dev_net(skb->dev); 977 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 978 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset); 979 struct xfrm_state *x; 980 981 if (type != ICMPV6_PKT_TOOBIG && 982 type != NDISC_REDIRECT) 983 return 0; 984 985 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 986 esph->spi, IPPROTO_ESP, AF_INET6); 987 if (!x) 988 return 0; 989 990 if (type == NDISC_REDIRECT) 991 ip6_redirect(skb, net, skb->dev->ifindex, 0, 992 sock_net_uid(net, NULL)); 993 else 994 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 995 xfrm_state_put(x); 996 997 return 0; 998 } 999 1000 static void esp6_destroy(struct xfrm_state *x) 1001 { 1002 struct crypto_aead *aead = x->data; 1003 1004 if (!aead) 1005 return; 1006 1007 crypto_free_aead(aead); 1008 } 1009 1010 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 1011 { 1012 char aead_name[CRYPTO_MAX_ALG_NAME]; 1013 struct crypto_aead *aead; 1014 int err; 1015 1016 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1017 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 1018 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1019 return -ENAMETOOLONG; 1020 } 1021 1022 aead = crypto_alloc_aead(aead_name, 0, 0); 1023 err = PTR_ERR(aead); 1024 if (IS_ERR(aead)) 1025 goto error; 1026 1027 x->data = aead; 1028 1029 err = crypto_aead_setkey(aead, x->aead->alg_key, 1030 (x->aead->alg_key_len + 7) / 8); 1031 if (err) 1032 goto error; 1033 1034 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1035 if (err) 1036 goto error; 1037 1038 return 0; 1039 1040 error: 1041 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1042 return err; 1043 } 1044 1045 static int esp_init_authenc(struct xfrm_state *x, 1046 struct netlink_ext_ack *extack) 1047 { 1048 struct crypto_aead *aead; 1049 struct crypto_authenc_key_param *param; 1050 struct rtattr *rta; 1051 char *key; 1052 char *p; 1053 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1054 unsigned int keylen; 1055 int err; 1056 1057 err = -ENAMETOOLONG; 1058 1059 if ((x->props.flags & XFRM_STATE_ESN)) { 1060 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1061 "%s%sauthencesn(%s,%s)%s", 1062 x->geniv ?: "", x->geniv ? "(" : "", 1063 x->aalg ? x->aalg->alg_name : "digest_null", 1064 x->ealg->alg_name, 1065 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1066 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1067 goto error; 1068 } 1069 } else { 1070 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1071 "%s%sauthenc(%s,%s)%s", 1072 x->geniv ?: "", x->geniv ? "(" : "", 1073 x->aalg ? x->aalg->alg_name : "digest_null", 1074 x->ealg->alg_name, 1075 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1076 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1077 goto error; 1078 } 1079 } 1080 1081 aead = crypto_alloc_aead(authenc_name, 0, 0); 1082 err = PTR_ERR(aead); 1083 if (IS_ERR(aead)) { 1084 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1085 goto error; 1086 } 1087 1088 x->data = aead; 1089 1090 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1091 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1092 err = -ENOMEM; 1093 key = kmalloc(keylen, GFP_KERNEL); 1094 if (!key) 1095 goto error; 1096 1097 p = key; 1098 rta = (void *)p; 1099 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1100 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1101 param = RTA_DATA(rta); 1102 p += RTA_SPACE(sizeof(*param)); 1103 1104 if (x->aalg) { 1105 struct xfrm_algo_desc *aalg_desc; 1106 1107 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1108 p += (x->aalg->alg_key_len + 7) / 8; 1109 1110 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1111 BUG_ON(!aalg_desc); 1112 1113 err = -EINVAL; 1114 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1115 crypto_aead_authsize(aead)) { 1116 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1117 goto free_key; 1118 } 1119 1120 err = crypto_aead_setauthsize( 1121 aead, x->aalg->alg_trunc_len / 8); 1122 if (err) { 1123 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1124 goto free_key; 1125 } 1126 } 1127 1128 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1129 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1130 1131 err = crypto_aead_setkey(aead, key, keylen); 1132 1133 free_key: 1134 kfree(key); 1135 1136 error: 1137 return err; 1138 } 1139 1140 static int esp6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1141 { 1142 struct crypto_aead *aead; 1143 u32 align; 1144 int err; 1145 1146 x->data = NULL; 1147 1148 if (x->aead) { 1149 err = esp_init_aead(x, extack); 1150 } else if (x->ealg) { 1151 err = esp_init_authenc(x, extack); 1152 } else { 1153 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1154 err = -EINVAL; 1155 } 1156 1157 if (err) 1158 goto error; 1159 1160 aead = x->data; 1161 1162 x->props.header_len = sizeof(struct ip_esp_hdr) + 1163 crypto_aead_ivsize(aead); 1164 switch (x->props.mode) { 1165 case XFRM_MODE_BEET: 1166 if (x->sel.family != AF_INET6) 1167 x->props.header_len += IPV4_BEET_PHMAXLEN + 1168 (sizeof(struct ipv6hdr) - sizeof(struct iphdr)); 1169 break; 1170 default: 1171 case XFRM_MODE_TRANSPORT: 1172 break; 1173 case XFRM_MODE_TUNNEL: 1174 x->props.header_len += sizeof(struct ipv6hdr); 1175 break; 1176 } 1177 1178 if (x->encap) { 1179 struct xfrm_encap_tmpl *encap = x->encap; 1180 1181 switch (encap->encap_type) { 1182 default: 1183 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1184 err = -EINVAL; 1185 goto error; 1186 case UDP_ENCAP_ESPINUDP: 1187 x->props.header_len += sizeof(struct udphdr); 1188 break; 1189 #ifdef CONFIG_INET6_ESPINTCP 1190 case TCP_ENCAP_ESPINTCP: 1191 /* only the length field, TCP encap is done by 1192 * the socket 1193 */ 1194 x->props.header_len += 2; 1195 break; 1196 #endif 1197 } 1198 } 1199 1200 align = ALIGN(crypto_aead_blocksize(aead), 4); 1201 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1202 1203 error: 1204 return err; 1205 } 1206 1207 static int esp6_rcv_cb(struct sk_buff *skb, int err) 1208 { 1209 return 0; 1210 } 1211 1212 static const struct xfrm_type esp6_type = { 1213 .owner = THIS_MODULE, 1214 .proto = IPPROTO_ESP, 1215 .flags = XFRM_TYPE_REPLAY_PROT, 1216 .init_state = esp6_init_state, 1217 .destructor = esp6_destroy, 1218 .input = esp6_input, 1219 .output = esp6_output, 1220 }; 1221 1222 static struct xfrm6_protocol esp6_protocol = { 1223 .handler = xfrm6_rcv, 1224 .input_handler = xfrm_input, 1225 .cb_handler = esp6_rcv_cb, 1226 .err_handler = esp6_err, 1227 .priority = 0, 1228 }; 1229 1230 static int __init esp6_init(void) 1231 { 1232 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { 1233 pr_info("%s: can't add xfrm type\n", __func__); 1234 return -EAGAIN; 1235 } 1236 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) { 1237 pr_info("%s: can't add protocol\n", __func__); 1238 xfrm_unregister_type(&esp6_type, AF_INET6); 1239 return -EAGAIN; 1240 } 1241 1242 return 0; 1243 } 1244 1245 static void __exit esp6_fini(void) 1246 { 1247 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0) 1248 pr_info("%s: can't remove protocol\n", __func__); 1249 xfrm_unregister_type(&esp6_type, AF_INET6); 1250 } 1251 1252 module_init(esp6_init); 1253 module_exit(esp6_fini); 1254 1255 MODULE_DESCRIPTION("IPv6 ESP transformation helpers"); 1256 MODULE_LICENSE("GPL"); 1257 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP); 1258