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, bool already_unref) 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 (already_unref || req->src != req->dst) { 134 struct scatterlist *src = already_unref ? esp_req_sg(aead, req) : req->src; 135 136 for (sg = sg_next(src); sg; sg = sg_next(sg)) 137 skb_page_unref(page_to_netmem(sg_page(sg)), 138 skb->pp_recycle); 139 } 140 } 141 142 #ifdef CONFIG_INET6_ESPINTCP 143 static struct sock *esp6_find_tcp_sk(struct xfrm_state *x) 144 { 145 struct xfrm_encap_tmpl *encap = x->encap; 146 struct net *net = xs_net(x); 147 __be16 sport, dport; 148 struct sock *sk; 149 150 spin_lock_bh(&x->lock); 151 sport = encap->encap_sport; 152 dport = encap->encap_dport; 153 spin_unlock_bh(&x->lock); 154 155 sk = __inet6_lookup_established(net, &x->id.daddr.in6, dport, 156 &x->props.saddr.in6, ntohs(sport), 0, 0); 157 if (!sk) 158 return ERR_PTR(-ENOENT); 159 160 if (!tcp_is_ulp_esp(sk)) { 161 sock_put(sk); 162 return ERR_PTR(-EINVAL); 163 } 164 165 return sk; 166 } 167 168 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) 169 { 170 struct sock *sk; 171 int err; 172 173 rcu_read_lock(); 174 175 sk = esp6_find_tcp_sk(x); 176 err = PTR_ERR_OR_ZERO(sk); 177 if (err) { 178 kfree_skb(skb); 179 goto out; 180 } 181 182 bh_lock_sock(sk); 183 if (sock_owned_by_user(sk)) 184 err = espintcp_queue_out(sk, skb); 185 else 186 err = espintcp_push_skb(sk, skb); 187 bh_unlock_sock(sk); 188 189 sock_put(sk); 190 191 out: 192 rcu_read_unlock(); 193 return err; 194 } 195 196 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk, 197 struct sk_buff *skb) 198 { 199 struct dst_entry *dst = skb_dst(skb); 200 struct xfrm_state *x = dst->xfrm; 201 202 return esp_output_tcp_finish(x, skb); 203 } 204 205 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 206 { 207 int err; 208 209 local_bh_disable(); 210 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb); 211 local_bh_enable(); 212 213 /* EINPROGRESS just happens to do the right thing. It 214 * actually means that the skb has been consumed and 215 * isn't coming back. 216 */ 217 return err ?: -EINPROGRESS; 218 } 219 #else 220 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 221 { 222 WARN_ON(1); 223 return -EOPNOTSUPP; 224 } 225 #endif 226 227 static void esp_output_encap_csum(struct sk_buff *skb) 228 { 229 /* UDP encap with IPv6 requires a valid checksum */ 230 if (*skb_mac_header(skb) == IPPROTO_UDP) { 231 struct udphdr *uh = udp_hdr(skb); 232 struct ipv6hdr *ip6h = ipv6_hdr(skb); 233 /* esp6_output_udp_encap limits len to U16_MAX. */ 234 int len = udp_get_len_short(uh); 235 unsigned int offset = skb_transport_offset(skb); 236 __wsum csum = skb_checksum(skb, offset, skb->len - offset, 0); 237 238 uh->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, 239 len, IPPROTO_UDP, csum); 240 if (uh->check == 0) 241 uh->check = CSUM_MANGLED_0; 242 } 243 } 244 245 static void esp_output_done(void *data, int err) 246 { 247 struct sk_buff *skb = data; 248 struct xfrm_offload *xo = xfrm_offload(skb); 249 void *tmp; 250 struct xfrm_state *x; 251 252 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 253 struct sec_path *sp = skb_sec_path(skb); 254 255 x = sp->xvec[sp->len - 1]; 256 } else { 257 x = skb_dst(skb)->xfrm; 258 } 259 260 tmp = ESP_SKB_CB(skb)->tmp; 261 esp_ssg_unref(x, tmp, skb, false); 262 kfree(tmp); 263 264 esp_output_encap_csum(skb); 265 266 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 267 if (err) { 268 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR); 269 kfree_skb(skb); 270 return; 271 } 272 273 skb_push(skb, skb->data - skb_mac_header(skb)); 274 secpath_reset(skb); 275 xfrm_dev_resume(skb); 276 } else { 277 if (!err && 278 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) { 279 err = esp_output_tail_tcp(x, skb); 280 if (err != -EINPROGRESS) 281 kfree_skb(skb); 282 } else { 283 xfrm_output_resume(skb_to_full_sk(skb), skb, err); 284 } 285 } 286 } 287 288 /* Move ESP header back into place. */ 289 static void esp_restore_header(struct sk_buff *skb, unsigned int offset) 290 { 291 struct ip_esp_hdr *esph = (void *)(skb->data + offset); 292 void *tmp = ESP_SKB_CB(skb)->tmp; 293 __be32 *seqhi = esp_tmp_extra(tmp); 294 295 esph->seq_no = esph->spi; 296 esph->spi = *seqhi; 297 } 298 299 static void esp_output_restore_header(struct sk_buff *skb) 300 { 301 void *tmp = ESP_SKB_CB(skb)->tmp; 302 struct esp_output_extra *extra = esp_tmp_extra(tmp); 303 304 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff - 305 sizeof(__be32)); 306 } 307 308 static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb, 309 struct xfrm_state *x, 310 struct ip_esp_hdr *esph, 311 struct esp_output_extra *extra) 312 { 313 /* For ESN we move the header forward by 4 bytes to 314 * accommodate the high bits. We will move it back after 315 * encryption. 316 */ 317 if ((x->props.flags & XFRM_STATE_ESN)) { 318 __u32 seqhi; 319 struct xfrm_offload *xo = xfrm_offload(skb); 320 321 if (xo) 322 seqhi = xo->seq.hi; 323 else 324 seqhi = XFRM_SKB_CB(skb)->seq.output.hi; 325 326 extra->esphoff = (unsigned char *)esph - 327 skb_transport_header(skb); 328 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4); 329 extra->seqhi = esph->spi; 330 esph->seq_no = htonl(seqhi); 331 } 332 333 esph->spi = x->id.spi; 334 335 return esph; 336 } 337 338 static void esp_output_done_esn(void *data, int err) 339 { 340 struct sk_buff *skb = data; 341 342 esp_output_restore_header(skb); 343 esp_output_done(data, err); 344 } 345 346 static struct ip_esp_hdr *esp6_output_udp_encap(struct sk_buff *skb, 347 int encap_type, 348 struct esp_info *esp, 349 __be16 sport, 350 __be16 dport) 351 { 352 struct udphdr *uh; 353 unsigned int len; 354 355 len = skb->len + esp->tailen - skb_transport_offset(skb); 356 if (len > U16_MAX) 357 return ERR_PTR(-EMSGSIZE); 358 359 uh = (struct udphdr *)esp->esph; 360 uh->source = sport; 361 uh->dest = dport; 362 udp_set_len_short(uh, len); 363 uh->check = 0; 364 365 *skb_mac_header(skb) = IPPROTO_UDP; 366 367 return (struct ip_esp_hdr *)(uh + 1); 368 } 369 370 #ifdef CONFIG_INET6_ESPINTCP 371 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x, 372 struct sk_buff *skb, 373 struct esp_info *esp) 374 { 375 __be16 *lenp = (void *)esp->esph; 376 struct ip_esp_hdr *esph; 377 unsigned int len; 378 struct sock *sk; 379 380 len = skb->len + esp->tailen - skb_transport_offset(skb); 381 if (len > IP_MAX_MTU) 382 return ERR_PTR(-EMSGSIZE); 383 384 rcu_read_lock(); 385 sk = esp6_find_tcp_sk(x); 386 rcu_read_unlock(); 387 388 if (IS_ERR(sk)) 389 return ERR_CAST(sk); 390 391 sock_put(sk); 392 393 *lenp = htons(len); 394 esph = (struct ip_esp_hdr *)(lenp + 1); 395 396 return esph; 397 } 398 #else 399 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x, 400 struct sk_buff *skb, 401 struct esp_info *esp) 402 { 403 return ERR_PTR(-EOPNOTSUPP); 404 } 405 #endif 406 407 static int esp6_output_encap(struct xfrm_state *x, struct sk_buff *skb, 408 struct esp_info *esp) 409 { 410 struct xfrm_encap_tmpl *encap = x->encap; 411 struct ip_esp_hdr *esph; 412 __be16 sport, dport; 413 int encap_type; 414 415 spin_lock_bh(&x->lock); 416 sport = encap->encap_sport; 417 dport = encap->encap_dport; 418 encap_type = encap->encap_type; 419 spin_unlock_bh(&x->lock); 420 421 switch (encap_type) { 422 default: 423 case UDP_ENCAP_ESPINUDP: 424 esph = esp6_output_udp_encap(skb, encap_type, esp, sport, dport); 425 break; 426 case TCP_ENCAP_ESPINTCP: 427 esph = esp6_output_tcp_encap(x, skb, esp); 428 break; 429 } 430 431 if (IS_ERR(esph)) 432 return PTR_ERR(esph); 433 434 esp->esph = esph; 435 436 return 0; 437 } 438 439 int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 440 { 441 u8 *tail; 442 int nfrags; 443 int esph_offset; 444 struct page *page; 445 struct sk_buff *trailer; 446 int tailen = esp->tailen; 447 448 if (x->encap) { 449 int err = esp6_output_encap(x, skb, esp); 450 451 if (err < 0) 452 return err; 453 } 454 455 if (ALIGN(skb->data_len + tailen, L1_CACHE_BYTES) > 456 PAGE_SIZE) 457 goto cow; 458 459 if (!skb_cloned(skb)) { 460 if (tailen <= skb_tailroom(skb)) { 461 nfrags = 1; 462 trailer = skb; 463 tail = skb_tail_pointer(trailer); 464 465 goto skip_cow; 466 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 467 && !skb_has_frag_list(skb)) { 468 int allocsize; 469 struct sock *sk = skb->sk; 470 struct page_frag *pfrag = &x->xfrag; 471 472 esp->inplace = false; 473 474 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 475 476 spin_lock_bh(&x->lock); 477 478 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 479 spin_unlock_bh(&x->lock); 480 goto cow; 481 } 482 483 page = pfrag->page; 484 get_page(page); 485 486 tail = page_address(page) + pfrag->offset; 487 488 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 489 490 nfrags = skb_shinfo(skb)->nr_frags; 491 492 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 493 tailen); 494 skb_shinfo(skb)->nr_frags = ++nfrags; 495 496 pfrag->offset = pfrag->offset + allocsize; 497 498 spin_unlock_bh(&x->lock); 499 500 nfrags++; 501 502 skb->len += tailen; 503 skb->data_len += tailen; 504 skb->truesize += tailen; 505 if (sk && sk_fullsock(sk)) 506 refcount_add(tailen, &sk->sk_wmem_alloc); 507 508 goto out; 509 } 510 } 511 512 cow: 513 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 514 515 nfrags = skb_cow_data(skb, tailen, &trailer); 516 if (nfrags < 0) 517 goto out; 518 tail = skb_tail_pointer(trailer); 519 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 520 521 skip_cow: 522 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 523 pskb_put(skb, trailer, tailen); 524 525 out: 526 return nfrags; 527 } 528 EXPORT_SYMBOL_GPL(esp6_output_head); 529 530 int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 531 { 532 u8 *iv; 533 int alen; 534 void *tmp; 535 int ivlen; 536 int assoclen; 537 int extralen; 538 struct page *page; 539 struct ip_esp_hdr *esph; 540 struct aead_request *req; 541 struct crypto_aead *aead; 542 struct scatterlist *sg, *dsg; 543 struct esp_output_extra *extra; 544 int err = -ENOMEM; 545 546 assoclen = sizeof(struct ip_esp_hdr); 547 extralen = 0; 548 549 if (x->props.flags & XFRM_STATE_ESN) { 550 extralen += sizeof(*extra); 551 assoclen += sizeof(__be32); 552 } 553 554 aead = x->data; 555 alen = crypto_aead_authsize(aead); 556 ivlen = crypto_aead_ivsize(aead); 557 558 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 559 if (!tmp) 560 goto error; 561 562 extra = esp_tmp_extra(tmp); 563 iv = esp_tmp_iv(aead, tmp, extralen); 564 req = esp_tmp_req(aead, iv); 565 sg = esp_req_sg(aead, req); 566 567 if (esp->inplace) 568 dsg = sg; 569 else 570 dsg = &sg[esp->nfrags]; 571 572 esph = esp_output_set_esn(skb, x, esp->esph, extra); 573 esp->esph = esph; 574 575 sg_init_table(sg, esp->nfrags); 576 err = skb_to_sgvec(skb, sg, 577 (unsigned char *)esph - skb->data, 578 assoclen + ivlen + esp->clen + alen); 579 if (unlikely(err < 0)) 580 goto error_free; 581 582 if (!esp->inplace) { 583 int allocsize; 584 struct page_frag *pfrag = &x->xfrag; 585 586 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 587 588 spin_lock_bh(&x->lock); 589 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 590 spin_unlock_bh(&x->lock); 591 goto error_free; 592 } 593 594 skb_shinfo(skb)->nr_frags = 1; 595 596 page = pfrag->page; 597 get_page(page); 598 /* replace page frags in skb with new page */ 599 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 600 pfrag->offset = pfrag->offset + allocsize; 601 spin_unlock_bh(&x->lock); 602 603 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 604 err = skb_to_sgvec(skb, dsg, 605 (unsigned char *)esph - skb->data, 606 assoclen + ivlen + esp->clen + alen); 607 if (unlikely(err < 0)) { 608 esp_ssg_unref(x, tmp, skb, true); 609 goto error_free; 610 } 611 } 612 613 if ((x->props.flags & XFRM_STATE_ESN)) 614 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 615 else 616 aead_request_set_callback(req, 0, esp_output_done, skb); 617 618 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 619 aead_request_set_ad(req, assoclen); 620 621 memset(iv, 0, ivlen); 622 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 623 min(ivlen, 8)); 624 625 ESP_SKB_CB(skb)->tmp = tmp; 626 err = crypto_aead_encrypt(req); 627 628 switch (err) { 629 case -EINPROGRESS: 630 goto error; 631 632 case -ENOSPC: 633 err = NET_XMIT_DROP; 634 break; 635 636 case 0: 637 if ((x->props.flags & XFRM_STATE_ESN)) 638 esp_output_restore_header(skb); 639 esp_output_encap_csum(skb); 640 } 641 642 if (sg != dsg) 643 esp_ssg_unref(x, tmp, skb, false); 644 645 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 646 err = esp_output_tail_tcp(x, skb); 647 648 error_free: 649 kfree(tmp); 650 error: 651 return err; 652 } 653 EXPORT_SYMBOL_GPL(esp6_output_tail); 654 655 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) 656 { 657 int alen; 658 int blksize; 659 struct ip_esp_hdr *esph; 660 struct crypto_aead *aead; 661 struct esp_info esp; 662 663 esp.inplace = true; 664 665 esp.proto = *skb_mac_header(skb); 666 *skb_mac_header(skb) = IPPROTO_ESP; 667 668 /* skb is pure payload to encrypt */ 669 670 aead = x->data; 671 alen = crypto_aead_authsize(aead); 672 673 esp.tfclen = 0; 674 if (x->tfcpad) { 675 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 676 u32 padto; 677 678 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 679 if (skb->len < padto) 680 esp.tfclen = padto - skb->len; 681 } 682 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 683 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 684 esp.plen = esp.clen - skb->len - esp.tfclen; 685 esp.tailen = esp.tfclen + esp.plen + alen; 686 687 esp.esph = ip_esp_hdr(skb); 688 689 esp.nfrags = esp6_output_head(x, skb, &esp); 690 if (esp.nfrags < 0) 691 return esp.nfrags; 692 693 esph = esp.esph; 694 esph->spi = x->id.spi; 695 696 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 697 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 698 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 699 700 skb_push(skb, -skb_network_offset(skb)); 701 702 return esp6_output_tail(x, skb, &esp); 703 } 704 705 static inline int esp_remove_trailer(struct sk_buff *skb) 706 { 707 struct xfrm_state *x = xfrm_input_state(skb); 708 struct crypto_aead *aead = x->data; 709 int alen, hlen, elen; 710 int padlen, trimlen; 711 __wsum csumdiff; 712 u8 nexthdr[2]; 713 int ret; 714 715 alen = crypto_aead_authsize(aead); 716 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 717 elen = skb->len - hlen; 718 719 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2); 720 BUG_ON(ret); 721 722 ret = -EINVAL; 723 padlen = nexthdr[0]; 724 if (padlen + 2 + alen >= elen) { 725 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 726 padlen + 2, elen - alen); 727 goto out; 728 } 729 730 trimlen = alen + padlen + 2; 731 if (skb->ip_summed == CHECKSUM_COMPLETE) { 732 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 733 skb->csum = csum_block_sub(skb->csum, csumdiff, 734 skb->len - trimlen); 735 } 736 ret = pskb_trim(skb, skb->len - trimlen); 737 if (unlikely(ret)) 738 return ret; 739 740 ret = nexthdr[1]; 741 742 out: 743 return ret; 744 } 745 746 int esp6_input_done2(struct sk_buff *skb, int err) 747 { 748 struct xfrm_state *x = xfrm_input_state(skb); 749 struct xfrm_offload *xo = xfrm_offload(skb); 750 struct crypto_aead *aead = x->data; 751 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 752 int hdr_len = skb_network_header_len(skb); 753 754 if (!xo || !(xo->flags & CRYPTO_DONE)) 755 kfree(ESP_SKB_CB(skb)->tmp); 756 757 if (unlikely(err)) 758 goto out; 759 760 err = esp_remove_trailer(skb); 761 if (unlikely(err < 0)) 762 goto out; 763 764 if (x->encap) { 765 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 766 int offset = skb_network_offset(skb) + sizeof(*ip6h); 767 struct xfrm_encap_tmpl *encap = x->encap; 768 u8 nexthdr = ip6h->nexthdr; 769 __be16 frag_off, source; 770 struct udphdr *uh; 771 struct tcphdr *th; 772 773 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); 774 if (offset == -1) { 775 err = -EINVAL; 776 goto out; 777 } 778 779 uh = (void *)(skb->data + offset); 780 th = (void *)(skb->data + offset); 781 hdr_len += offset; 782 783 switch (x->encap->encap_type) { 784 case TCP_ENCAP_ESPINTCP: 785 source = th->source; 786 break; 787 case UDP_ENCAP_ESPINUDP: 788 source = uh->source; 789 break; 790 default: 791 WARN_ON_ONCE(1); 792 err = -EINVAL; 793 goto out; 794 } 795 796 /* 797 * 1) if the NAT-T peer's IP or port changed then 798 * advertise the change to the keying daemon. 799 * This is an inbound SA, so just compare 800 * SRC ports. 801 */ 802 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) || 803 source != encap->encap_sport) { 804 xfrm_address_t ipaddr; 805 806 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6)); 807 km_new_mapping(x, &ipaddr, source); 808 809 /* XXX: perhaps add an extra 810 * policy check here, to see 811 * if we should allow or 812 * reject a packet from a 813 * different source 814 * address/port. 815 */ 816 } 817 818 /* 819 * 2) ignore UDP/TCP checksums in case 820 * of NAT-T in Transport Mode, or 821 * perform other post-processing fixes 822 * as per draft-ietf-ipsec-udp-encaps-06, 823 * section 3.1.2 824 */ 825 if (x->props.mode == XFRM_MODE_TRANSPORT) 826 skb->ip_summed = CHECKSUM_UNNECESSARY; 827 } 828 829 skb_postpull_rcsum(skb, skb_network_header(skb), 830 skb_network_header_len(skb)); 831 skb_pull_rcsum(skb, hlen); 832 if (x->props.mode == XFRM_MODE_TUNNEL || 833 x->props.mode == XFRM_MODE_IPTFS) 834 skb_reset_transport_header(skb); 835 else 836 skb_set_transport_header(skb, -hdr_len); 837 838 /* RFC4303: Drop dummy packets without any error */ 839 if (err == IPPROTO_NONE) 840 err = -EINVAL; 841 842 out: 843 return err; 844 } 845 EXPORT_SYMBOL_GPL(esp6_input_done2); 846 847 static void esp_input_done(void *data, int err) 848 { 849 struct sk_buff *skb = data; 850 851 xfrm_input_resume(skb, esp6_input_done2(skb, err)); 852 } 853 854 static void esp_input_restore_header(struct sk_buff *skb) 855 { 856 esp_restore_header(skb, 0); 857 __skb_pull(skb, 4); 858 } 859 860 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 861 { 862 struct xfrm_state *x = xfrm_input_state(skb); 863 864 /* For ESN we move the header forward by 4 bytes to 865 * accommodate the high bits. We will move it back after 866 * decryption. 867 */ 868 if ((x->props.flags & XFRM_STATE_ESN)) { 869 struct ip_esp_hdr *esph = skb_push(skb, 4); 870 871 *seqhi = esph->spi; 872 esph->spi = esph->seq_no; 873 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 874 } 875 } 876 877 static void esp_input_done_esn(void *data, int err) 878 { 879 struct sk_buff *skb = data; 880 881 esp_input_restore_header(skb); 882 esp_input_done(data, err); 883 } 884 885 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) 886 { 887 struct crypto_aead *aead = x->data; 888 struct aead_request *req; 889 struct sk_buff *trailer; 890 int ivlen = crypto_aead_ivsize(aead); 891 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 892 int nfrags; 893 int assoclen; 894 int seqhilen; 895 int ret = 0; 896 void *tmp; 897 __be32 *seqhi; 898 u8 *iv; 899 struct scatterlist *sg; 900 901 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) { 902 ret = -EINVAL; 903 goto out; 904 } 905 906 if (elen <= 0) { 907 ret = -EINVAL; 908 goto out; 909 } 910 911 assoclen = sizeof(struct ip_esp_hdr); 912 seqhilen = 0; 913 914 if (x->props.flags & XFRM_STATE_ESN) { 915 seqhilen += sizeof(__be32); 916 assoclen += seqhilen; 917 } 918 919 if (!skb_cloned(skb)) { 920 if (!skb_is_nonlinear(skb)) { 921 nfrags = 1; 922 923 goto skip_cow; 924 } else if (!skb_has_frag_list(skb) && 925 !skb_has_shared_frag(skb)) { 926 nfrags = skb_shinfo(skb)->nr_frags; 927 nfrags++; 928 929 goto skip_cow; 930 } 931 } 932 933 nfrags = skb_cow_data(skb, 0, &trailer); 934 if (nfrags < 0) { 935 ret = -EINVAL; 936 goto out; 937 } 938 939 skip_cow: 940 ret = -ENOMEM; 941 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 942 if (!tmp) 943 goto out; 944 945 ESP_SKB_CB(skb)->tmp = tmp; 946 seqhi = esp_tmp_extra(tmp); 947 iv = esp_tmp_iv(aead, tmp, seqhilen); 948 req = esp_tmp_req(aead, iv); 949 sg = esp_req_sg(aead, req); 950 951 esp_input_set_header(skb, seqhi); 952 953 sg_init_table(sg, nfrags); 954 ret = skb_to_sgvec(skb, sg, 0, skb->len); 955 if (unlikely(ret < 0)) { 956 kfree(tmp); 957 goto out; 958 } 959 960 skb->ip_summed = CHECKSUM_NONE; 961 962 if ((x->props.flags & XFRM_STATE_ESN)) 963 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 964 else 965 aead_request_set_callback(req, 0, esp_input_done, skb); 966 967 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 968 aead_request_set_ad(req, assoclen); 969 970 ret = crypto_aead_decrypt(req); 971 if (ret == -EINPROGRESS) 972 goto out; 973 974 if ((x->props.flags & XFRM_STATE_ESN)) 975 esp_input_restore_header(skb); 976 977 ret = esp6_input_done2(skb, ret); 978 979 out: 980 return ret; 981 } 982 983 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 984 u8 type, u8 code, int offset, __be32 info) 985 { 986 struct net *net = dev_net(skb->dev); 987 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 988 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset); 989 struct xfrm_state *x; 990 991 if (type != ICMPV6_PKT_TOOBIG && 992 type != NDISC_REDIRECT) 993 return 0; 994 995 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 996 esph->spi, IPPROTO_ESP, AF_INET6); 997 if (!x) 998 return 0; 999 1000 if (type == NDISC_REDIRECT) 1001 ip6_redirect(skb, net, skb->dev->ifindex, 0, 1002 sock_net_uid(net, NULL)); 1003 else 1004 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 1005 xfrm_state_put(x); 1006 1007 return 0; 1008 } 1009 1010 static void esp6_destroy(struct xfrm_state *x) 1011 { 1012 struct crypto_aead *aead = x->data; 1013 1014 if (!aead) 1015 return; 1016 1017 crypto_free_aead(aead); 1018 } 1019 1020 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 1021 { 1022 char aead_name[CRYPTO_MAX_ALG_NAME]; 1023 struct crypto_aead *aead; 1024 int err; 1025 1026 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1027 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 1028 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1029 return -ENAMETOOLONG; 1030 } 1031 1032 aead = crypto_alloc_aead(aead_name, 0, 0); 1033 err = PTR_ERR(aead); 1034 if (IS_ERR(aead)) 1035 goto error; 1036 1037 x->data = aead; 1038 1039 err = crypto_aead_setkey(aead, x->aead->alg_key, 1040 (x->aead->alg_key_len + 7) / 8); 1041 if (err) 1042 goto error; 1043 1044 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1045 if (err) 1046 goto error; 1047 1048 return 0; 1049 1050 error: 1051 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1052 return err; 1053 } 1054 1055 static int esp_init_authenc(struct xfrm_state *x, 1056 struct netlink_ext_ack *extack) 1057 { 1058 struct crypto_aead *aead; 1059 struct crypto_authenc_key_param *param; 1060 struct rtattr *rta; 1061 char *key; 1062 char *p; 1063 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1064 unsigned int keylen; 1065 int err; 1066 1067 err = -ENAMETOOLONG; 1068 1069 if ((x->props.flags & XFRM_STATE_ESN)) { 1070 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1071 "%s%sauthencesn(%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 } else { 1080 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1081 "%s%sauthenc(%s,%s)%s", 1082 x->geniv ?: "", x->geniv ? "(" : "", 1083 x->aalg ? x->aalg->alg_name : "digest_null", 1084 x->ealg->alg_name, 1085 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1086 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1087 goto error; 1088 } 1089 } 1090 1091 aead = crypto_alloc_aead(authenc_name, 0, 0); 1092 err = PTR_ERR(aead); 1093 if (IS_ERR(aead)) { 1094 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1095 goto error; 1096 } 1097 1098 x->data = aead; 1099 1100 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1101 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1102 err = -ENOMEM; 1103 key = kmalloc(keylen, GFP_KERNEL); 1104 if (!key) 1105 goto error; 1106 1107 p = key; 1108 rta = (void *)p; 1109 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1110 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1111 param = RTA_DATA(rta); 1112 p += RTA_SPACE(sizeof(*param)); 1113 1114 if (x->aalg) { 1115 struct xfrm_algo_desc *aalg_desc; 1116 1117 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1118 p += (x->aalg->alg_key_len + 7) / 8; 1119 1120 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1121 BUG_ON(!aalg_desc); 1122 1123 err = -EINVAL; 1124 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1125 crypto_aead_authsize(aead)) { 1126 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1127 goto free_key; 1128 } 1129 1130 err = crypto_aead_setauthsize( 1131 aead, x->aalg->alg_trunc_len / 8); 1132 if (err) { 1133 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1134 goto free_key; 1135 } 1136 } 1137 1138 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1139 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1140 1141 err = crypto_aead_setkey(aead, key, keylen); 1142 1143 free_key: 1144 kfree(key); 1145 1146 error: 1147 return err; 1148 } 1149 1150 static int esp6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1151 { 1152 struct crypto_aead *aead; 1153 u32 align; 1154 int err; 1155 1156 x->data = NULL; 1157 1158 if (x->aead) { 1159 err = esp_init_aead(x, extack); 1160 } else if (x->ealg) { 1161 err = esp_init_authenc(x, extack); 1162 } else { 1163 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1164 err = -EINVAL; 1165 } 1166 1167 if (err) 1168 goto error; 1169 1170 aead = x->data; 1171 1172 x->props.header_len = sizeof(struct ip_esp_hdr) + 1173 crypto_aead_ivsize(aead); 1174 switch (x->props.mode) { 1175 case XFRM_MODE_BEET: 1176 if (x->sel.family != AF_INET6) 1177 x->props.header_len += IPV4_BEET_PHMAXLEN + 1178 (sizeof(struct ipv6hdr) - sizeof(struct iphdr)); 1179 break; 1180 default: 1181 case XFRM_MODE_TRANSPORT: 1182 break; 1183 case XFRM_MODE_TUNNEL: 1184 x->props.header_len += sizeof(struct ipv6hdr); 1185 break; 1186 } 1187 1188 if (x->encap) { 1189 struct xfrm_encap_tmpl *encap = x->encap; 1190 1191 switch (encap->encap_type) { 1192 default: 1193 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1194 err = -EINVAL; 1195 goto error; 1196 case UDP_ENCAP_ESPINUDP: 1197 x->props.header_len += sizeof(struct udphdr); 1198 break; 1199 #ifdef CONFIG_INET6_ESPINTCP 1200 case TCP_ENCAP_ESPINTCP: 1201 /* only the length field, TCP encap is done by 1202 * the socket 1203 */ 1204 x->props.header_len += 2; 1205 break; 1206 #endif 1207 } 1208 } 1209 1210 align = ALIGN(crypto_aead_blocksize(aead), 4); 1211 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1212 1213 error: 1214 return err; 1215 } 1216 1217 static int esp6_rcv_cb(struct sk_buff *skb, int err) 1218 { 1219 return 0; 1220 } 1221 1222 static const struct xfrm_type esp6_type = { 1223 .owner = THIS_MODULE, 1224 .proto = IPPROTO_ESP, 1225 .flags = XFRM_TYPE_REPLAY_PROT, 1226 .init_state = esp6_init_state, 1227 .destructor = esp6_destroy, 1228 .input = esp6_input, 1229 .output = esp6_output, 1230 }; 1231 1232 static struct xfrm6_protocol esp6_protocol = { 1233 .handler = xfrm6_rcv, 1234 .input_handler = xfrm_input, 1235 .cb_handler = esp6_rcv_cb, 1236 .err_handler = esp6_err, 1237 .priority = 0, 1238 }; 1239 1240 static int __init esp6_init(void) 1241 { 1242 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { 1243 pr_info("%s: can't add xfrm type\n", __func__); 1244 return -EAGAIN; 1245 } 1246 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) { 1247 pr_info("%s: can't add protocol\n", __func__); 1248 xfrm_unregister_type(&esp6_type, AF_INET6); 1249 return -EAGAIN; 1250 } 1251 1252 return 0; 1253 } 1254 1255 static void __exit esp6_fini(void) 1256 { 1257 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0) 1258 pr_info("%s: can't remove protocol\n", __func__); 1259 xfrm_unregister_type(&esp6_type, AF_INET6); 1260 } 1261 1262 module_init(esp6_init); 1263 module_exit(esp6_fini); 1264 1265 MODULE_DESCRIPTION("IPv6 ESP transformation helpers"); 1266 MODULE_LICENSE("GPL"); 1267 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP); 1268