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 /* Take real page refs and clear SKBFL_MANAGED_FRAG_REFS before 475 * we mutate the frag array, so the per-frag unref stays balanced 476 * for zerocopy managed frags (see __ip_append_data()). 477 */ 478 skb_zcopy_downgrade_managed(skb); 479 480 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 481 482 spin_lock_bh(&x->lock); 483 484 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 485 spin_unlock_bh(&x->lock); 486 goto cow; 487 } 488 489 page = pfrag->page; 490 get_page(page); 491 492 tail = page_address(page) + pfrag->offset; 493 494 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 495 496 nfrags = skb_shinfo(skb)->nr_frags; 497 498 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 499 tailen); 500 skb_shinfo(skb)->nr_frags = ++nfrags; 501 502 pfrag->offset = pfrag->offset + allocsize; 503 504 spin_unlock_bh(&x->lock); 505 506 nfrags++; 507 508 skb->len += tailen; 509 skb->data_len += tailen; 510 skb->truesize += tailen; 511 if (sk && sk_fullsock(sk)) 512 refcount_add(tailen, &sk->sk_wmem_alloc); 513 514 goto out; 515 } 516 } 517 518 cow: 519 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 520 521 nfrags = skb_cow_data(skb, tailen, &trailer); 522 if (nfrags < 0) 523 goto out; 524 tail = skb_tail_pointer(trailer); 525 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 526 527 skip_cow: 528 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 529 pskb_put(skb, trailer, tailen); 530 531 out: 532 return nfrags; 533 } 534 EXPORT_SYMBOL_GPL(esp6_output_head); 535 536 int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 537 { 538 u8 *iv; 539 int alen; 540 void *tmp; 541 int ivlen; 542 int assoclen; 543 int extralen; 544 struct page *page; 545 struct ip_esp_hdr *esph; 546 struct aead_request *req; 547 struct crypto_aead *aead; 548 struct scatterlist *sg, *dsg; 549 struct esp_output_extra *extra; 550 int err = -ENOMEM; 551 552 assoclen = sizeof(struct ip_esp_hdr); 553 extralen = 0; 554 555 if (x->props.flags & XFRM_STATE_ESN) { 556 extralen += sizeof(*extra); 557 assoclen += sizeof(__be32); 558 } 559 560 aead = x->data; 561 alen = crypto_aead_authsize(aead); 562 ivlen = crypto_aead_ivsize(aead); 563 564 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 565 if (!tmp) 566 goto error; 567 568 extra = esp_tmp_extra(tmp); 569 iv = esp_tmp_iv(aead, tmp, extralen); 570 req = esp_tmp_req(aead, iv); 571 sg = esp_req_sg(aead, req); 572 573 if (esp->inplace) 574 dsg = sg; 575 else 576 dsg = &sg[esp->nfrags]; 577 578 esph = esp_output_set_esn(skb, x, esp->esph, extra); 579 esp->esph = esph; 580 581 sg_init_table(sg, esp->nfrags); 582 err = skb_to_sgvec(skb, sg, 583 (unsigned char *)esph - skb->data, 584 assoclen + ivlen + esp->clen + alen); 585 if (unlikely(err < 0)) 586 goto error_free; 587 588 if (!esp->inplace) { 589 int allocsize; 590 struct page_frag *pfrag = &x->xfrag; 591 592 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 593 594 spin_lock_bh(&x->lock); 595 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 596 spin_unlock_bh(&x->lock); 597 goto error_free; 598 } 599 600 skb_shinfo(skb)->nr_frags = 1; 601 602 page = pfrag->page; 603 get_page(page); 604 /* replace page frags in skb with new page */ 605 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 606 pfrag->offset = pfrag->offset + allocsize; 607 spin_unlock_bh(&x->lock); 608 609 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 610 err = skb_to_sgvec(skb, dsg, 611 (unsigned char *)esph - skb->data, 612 assoclen + ivlen + esp->clen + alen); 613 if (unlikely(err < 0)) { 614 esp_ssg_unref(x, tmp, skb, true); 615 goto error_free; 616 } 617 } 618 619 if ((x->props.flags & XFRM_STATE_ESN)) 620 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 621 else 622 aead_request_set_callback(req, 0, esp_output_done, skb); 623 624 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 625 aead_request_set_ad(req, assoclen); 626 627 memset(iv, 0, ivlen); 628 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 629 min(ivlen, 8)); 630 631 ESP_SKB_CB(skb)->tmp = tmp; 632 err = crypto_aead_encrypt(req); 633 634 switch (err) { 635 case -EINPROGRESS: 636 goto error; 637 638 case -ENOSPC: 639 err = NET_XMIT_DROP; 640 break; 641 642 case 0: 643 if ((x->props.flags & XFRM_STATE_ESN)) 644 esp_output_restore_header(skb); 645 esp_output_encap_csum(skb); 646 } 647 648 if (sg != dsg) 649 esp_ssg_unref(x, tmp, skb, false); 650 651 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 652 err = esp_output_tail_tcp(x, skb); 653 654 error_free: 655 kfree(tmp); 656 error: 657 return err; 658 } 659 EXPORT_SYMBOL_GPL(esp6_output_tail); 660 661 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) 662 { 663 int alen; 664 int blksize; 665 struct ip_esp_hdr *esph; 666 struct crypto_aead *aead; 667 struct esp_info esp; 668 669 esp.inplace = true; 670 671 esp.proto = *skb_mac_header(skb); 672 *skb_mac_header(skb) = IPPROTO_ESP; 673 674 /* skb is pure payload to encrypt */ 675 676 aead = x->data; 677 alen = crypto_aead_authsize(aead); 678 679 esp.tfclen = 0; 680 if (x->tfcpad) { 681 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 682 u32 padto; 683 684 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 685 if (skb->len < padto) 686 esp.tfclen = padto - skb->len; 687 } 688 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 689 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 690 esp.plen = esp.clen - skb->len - esp.tfclen; 691 esp.tailen = esp.tfclen + esp.plen + alen; 692 693 esp.esph = ip_esp_hdr(skb); 694 695 esp.nfrags = esp6_output_head(x, skb, &esp); 696 if (esp.nfrags < 0) 697 return esp.nfrags; 698 699 esph = esp.esph; 700 esph->spi = x->id.spi; 701 702 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 703 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 704 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 705 706 skb_push(skb, -skb_network_offset(skb)); 707 708 return esp6_output_tail(x, skb, &esp); 709 } 710 711 static inline int esp_remove_trailer(struct sk_buff *skb) 712 { 713 struct xfrm_state *x = xfrm_input_state(skb); 714 struct crypto_aead *aead = x->data; 715 int alen, hlen, elen; 716 int padlen, trimlen; 717 __wsum csumdiff; 718 u8 nexthdr[2]; 719 int ret; 720 721 alen = crypto_aead_authsize(aead); 722 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 723 elen = skb->len - hlen; 724 725 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2); 726 BUG_ON(ret); 727 728 ret = -EINVAL; 729 padlen = nexthdr[0]; 730 if (padlen + 2 + alen >= elen) { 731 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 732 padlen + 2, elen - alen); 733 goto out; 734 } 735 736 trimlen = alen + padlen + 2; 737 if (skb->ip_summed == CHECKSUM_COMPLETE) { 738 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 739 skb->csum = csum_block_sub(skb->csum, csumdiff, 740 skb->len - trimlen); 741 } 742 ret = pskb_trim(skb, skb->len - trimlen); 743 if (unlikely(ret)) 744 return ret; 745 746 ret = nexthdr[1]; 747 748 out: 749 return ret; 750 } 751 752 int esp6_input_done2(struct sk_buff *skb, int err) 753 { 754 struct xfrm_state *x = xfrm_input_state(skb); 755 struct xfrm_offload *xo = xfrm_offload(skb); 756 struct crypto_aead *aead = x->data; 757 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 758 int hdr_len = skb_network_header_len(skb); 759 760 if (!xo || !(xo->flags & CRYPTO_DONE)) 761 kfree(ESP_SKB_CB(skb)->tmp); 762 763 if (unlikely(err)) 764 goto out; 765 766 err = esp_remove_trailer(skb); 767 if (unlikely(err < 0)) 768 goto out; 769 770 if (x->encap) { 771 const struct ipv6hdr *ip6h = ipv6_hdr(skb); 772 int offset = skb_network_offset(skb) + sizeof(*ip6h); 773 struct xfrm_encap_tmpl *encap = x->encap; 774 u8 nexthdr = ip6h->nexthdr; 775 __be16 frag_off, source; 776 struct udphdr *uh; 777 struct tcphdr *th; 778 779 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); 780 if (offset == -1) { 781 err = -EINVAL; 782 goto out; 783 } 784 785 uh = (void *)(skb->data + offset); 786 th = (void *)(skb->data + offset); 787 hdr_len += offset; 788 789 switch (x->encap->encap_type) { 790 case TCP_ENCAP_ESPINTCP: 791 source = th->source; 792 break; 793 case UDP_ENCAP_ESPINUDP: 794 source = uh->source; 795 break; 796 default: 797 WARN_ON_ONCE(1); 798 err = -EINVAL; 799 goto out; 800 } 801 802 /* 803 * 1) if the NAT-T peer's IP or port changed then 804 * advertise the change to the keying daemon. 805 * This is an inbound SA, so just compare 806 * SRC ports. 807 */ 808 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) || 809 source != encap->encap_sport) { 810 xfrm_address_t ipaddr; 811 812 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6)); 813 km_new_mapping(x, &ipaddr, source); 814 815 /* XXX: perhaps add an extra 816 * policy check here, to see 817 * if we should allow or 818 * reject a packet from a 819 * different source 820 * address/port. 821 */ 822 } 823 824 /* 825 * 2) ignore UDP/TCP checksums in case 826 * of NAT-T in Transport Mode, or 827 * perform other post-processing fixes 828 * as per draft-ietf-ipsec-udp-encaps-06, 829 * section 3.1.2 830 */ 831 if (x->props.mode == XFRM_MODE_TRANSPORT) 832 skb->ip_summed = CHECKSUM_UNNECESSARY; 833 } 834 835 skb_postpull_rcsum(skb, skb_network_header(skb), 836 skb_network_header_len(skb)); 837 skb_pull_rcsum(skb, hlen); 838 if (x->props.mode == XFRM_MODE_TUNNEL || 839 x->props.mode == XFRM_MODE_IPTFS) 840 skb_reset_transport_header(skb); 841 else 842 skb_set_transport_header(skb, -hdr_len); 843 844 /* RFC4303: Drop dummy packets without any error */ 845 if (err == IPPROTO_NONE) 846 err = -EINVAL; 847 848 out: 849 return err; 850 } 851 EXPORT_SYMBOL_GPL(esp6_input_done2); 852 853 static void esp_input_done(void *data, int err) 854 { 855 struct sk_buff *skb = data; 856 857 xfrm_input_resume(skb, esp6_input_done2(skb, err)); 858 } 859 860 static void esp_input_restore_header(struct sk_buff *skb) 861 { 862 esp_restore_header(skb, 0); 863 __skb_pull(skb, 4); 864 } 865 866 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 867 { 868 struct xfrm_state *x = xfrm_input_state(skb); 869 870 /* For ESN we move the header forward by 4 bytes to 871 * accommodate the high bits. We will move it back after 872 * decryption. 873 */ 874 if ((x->props.flags & XFRM_STATE_ESN)) { 875 struct ip_esp_hdr *esph = skb_push(skb, 4); 876 877 *seqhi = esph->spi; 878 esph->spi = esph->seq_no; 879 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 880 } 881 } 882 883 static void esp_input_done_esn(void *data, int err) 884 { 885 struct sk_buff *skb = data; 886 887 esp_input_restore_header(skb); 888 esp_input_done(data, err); 889 } 890 891 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) 892 { 893 struct crypto_aead *aead = x->data; 894 struct aead_request *req; 895 struct sk_buff *trailer; 896 int ivlen = crypto_aead_ivsize(aead); 897 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 898 int nfrags; 899 int assoclen; 900 int seqhilen; 901 int ret = 0; 902 void *tmp; 903 __be32 *seqhi; 904 u8 *iv; 905 struct scatterlist *sg; 906 907 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) { 908 ret = -EINVAL; 909 goto out; 910 } 911 912 if (elen <= 0) { 913 ret = -EINVAL; 914 goto out; 915 } 916 917 assoclen = sizeof(struct ip_esp_hdr); 918 seqhilen = 0; 919 920 if (x->props.flags & XFRM_STATE_ESN) { 921 seqhilen += sizeof(__be32); 922 assoclen += seqhilen; 923 } 924 925 if (!skb_cloned(skb)) { 926 if (!skb_is_nonlinear(skb)) { 927 nfrags = 1; 928 929 goto skip_cow; 930 } else if (!skb_has_frag_list(skb) && 931 !skb_has_shared_frag(skb)) { 932 nfrags = skb_shinfo(skb)->nr_frags; 933 nfrags++; 934 935 goto skip_cow; 936 } 937 } 938 939 nfrags = skb_cow_data(skb, 0, &trailer); 940 if (nfrags < 0) { 941 ret = -EINVAL; 942 goto out; 943 } 944 945 skip_cow: 946 ret = -ENOMEM; 947 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 948 if (!tmp) 949 goto out; 950 951 ESP_SKB_CB(skb)->tmp = tmp; 952 seqhi = esp_tmp_extra(tmp); 953 iv = esp_tmp_iv(aead, tmp, seqhilen); 954 req = esp_tmp_req(aead, iv); 955 sg = esp_req_sg(aead, req); 956 957 esp_input_set_header(skb, seqhi); 958 959 sg_init_table(sg, nfrags); 960 ret = skb_to_sgvec(skb, sg, 0, skb->len); 961 if (unlikely(ret < 0)) { 962 kfree(tmp); 963 goto out; 964 } 965 966 skb->ip_summed = CHECKSUM_NONE; 967 968 if ((x->props.flags & XFRM_STATE_ESN)) 969 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 970 else 971 aead_request_set_callback(req, 0, esp_input_done, skb); 972 973 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 974 aead_request_set_ad(req, assoclen); 975 976 ret = crypto_aead_decrypt(req); 977 if (ret == -EINPROGRESS) 978 goto out; 979 980 if ((x->props.flags & XFRM_STATE_ESN)) 981 esp_input_restore_header(skb); 982 983 ret = esp6_input_done2(skb, ret); 984 985 out: 986 return ret; 987 } 988 989 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 990 u8 type, u8 code, int offset, __be32 info) 991 { 992 struct net *net = dev_net(skb->dev); 993 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data; 994 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset); 995 struct xfrm_state *x; 996 997 if (type != ICMPV6_PKT_TOOBIG && 998 type != NDISC_REDIRECT) 999 return 0; 1000 1001 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 1002 esph->spi, IPPROTO_ESP, AF_INET6); 1003 if (!x) 1004 return 0; 1005 1006 if (type == NDISC_REDIRECT) 1007 ip6_redirect(skb, net, skb->dev->ifindex, 0, 1008 sock_net_uid(net, NULL)); 1009 else 1010 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 1011 xfrm_state_put(x); 1012 1013 return 0; 1014 } 1015 1016 static void esp6_destroy(struct xfrm_state *x) 1017 { 1018 struct crypto_aead *aead = x->data; 1019 1020 if (!aead) 1021 return; 1022 1023 crypto_free_aead(aead); 1024 } 1025 1026 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 1027 { 1028 char aead_name[CRYPTO_MAX_ALG_NAME]; 1029 struct crypto_aead *aead; 1030 int err; 1031 1032 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1033 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 1034 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1035 return -ENAMETOOLONG; 1036 } 1037 1038 aead = crypto_alloc_aead(aead_name, 0, 0); 1039 err = PTR_ERR(aead); 1040 if (IS_ERR(aead)) 1041 goto error; 1042 1043 x->data = aead; 1044 1045 err = crypto_aead_setkey(aead, x->aead->alg_key, 1046 (x->aead->alg_key_len + 7) / 8); 1047 if (err) 1048 goto error; 1049 1050 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1051 if (err) 1052 goto error; 1053 1054 return 0; 1055 1056 error: 1057 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1058 return err; 1059 } 1060 1061 static int esp_init_authenc(struct xfrm_state *x, 1062 struct netlink_ext_ack *extack) 1063 { 1064 struct crypto_aead *aead; 1065 struct crypto_authenc_key_param *param; 1066 struct rtattr *rta; 1067 char *key; 1068 char *p; 1069 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1070 unsigned int keylen; 1071 int err; 1072 1073 err = -ENAMETOOLONG; 1074 1075 if ((x->props.flags & XFRM_STATE_ESN)) { 1076 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1077 "%s%sauthencesn(%s,%s)%s", 1078 x->geniv ?: "", x->geniv ? "(" : "", 1079 x->aalg ? x->aalg->alg_name : "digest_null", 1080 x->ealg->alg_name, 1081 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1082 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1083 goto error; 1084 } 1085 } else { 1086 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1087 "%s%sauthenc(%s,%s)%s", 1088 x->geniv ?: "", x->geniv ? "(" : "", 1089 x->aalg ? x->aalg->alg_name : "digest_null", 1090 x->ealg->alg_name, 1091 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1092 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1093 goto error; 1094 } 1095 } 1096 1097 aead = crypto_alloc_aead(authenc_name, 0, 0); 1098 err = PTR_ERR(aead); 1099 if (IS_ERR(aead)) { 1100 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1101 goto error; 1102 } 1103 1104 x->data = aead; 1105 1106 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1107 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1108 err = -ENOMEM; 1109 key = kmalloc(keylen, GFP_KERNEL); 1110 if (!key) 1111 goto error; 1112 1113 p = key; 1114 rta = (void *)p; 1115 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1116 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1117 param = RTA_DATA(rta); 1118 p += RTA_SPACE(sizeof(*param)); 1119 1120 if (x->aalg) { 1121 struct xfrm_algo_desc *aalg_desc; 1122 1123 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1124 p += (x->aalg->alg_key_len + 7) / 8; 1125 1126 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1127 BUG_ON(!aalg_desc); 1128 1129 err = -EINVAL; 1130 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1131 crypto_aead_authsize(aead)) { 1132 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1133 goto free_key; 1134 } 1135 1136 err = crypto_aead_setauthsize( 1137 aead, x->aalg->alg_trunc_len / 8); 1138 if (err) { 1139 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1140 goto free_key; 1141 } 1142 } 1143 1144 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1145 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1146 1147 err = crypto_aead_setkey(aead, key, keylen); 1148 1149 free_key: 1150 kfree(key); 1151 1152 error: 1153 return err; 1154 } 1155 1156 static int esp6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1157 { 1158 struct crypto_aead *aead; 1159 u32 align; 1160 int err; 1161 1162 x->data = NULL; 1163 1164 if (x->aead) { 1165 err = esp_init_aead(x, extack); 1166 } else if (x->ealg) { 1167 err = esp_init_authenc(x, extack); 1168 } else { 1169 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1170 err = -EINVAL; 1171 } 1172 1173 if (err) 1174 goto error; 1175 1176 aead = x->data; 1177 1178 x->props.header_len = sizeof(struct ip_esp_hdr) + 1179 crypto_aead_ivsize(aead); 1180 switch (x->props.mode) { 1181 case XFRM_MODE_BEET: 1182 if (x->sel.family != AF_INET6) 1183 x->props.header_len += IPV4_BEET_PHMAXLEN + 1184 (sizeof(struct ipv6hdr) - sizeof(struct iphdr)); 1185 break; 1186 default: 1187 case XFRM_MODE_TRANSPORT: 1188 break; 1189 case XFRM_MODE_TUNNEL: 1190 x->props.header_len += sizeof(struct ipv6hdr); 1191 break; 1192 } 1193 1194 if (x->encap) { 1195 struct xfrm_encap_tmpl *encap = x->encap; 1196 1197 switch (encap->encap_type) { 1198 default: 1199 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1200 err = -EINVAL; 1201 goto error; 1202 case UDP_ENCAP_ESPINUDP: 1203 x->props.header_len += sizeof(struct udphdr); 1204 break; 1205 #ifdef CONFIG_INET6_ESPINTCP 1206 case TCP_ENCAP_ESPINTCP: 1207 /* only the length field, TCP encap is done by 1208 * the socket 1209 */ 1210 x->props.header_len += 2; 1211 break; 1212 #endif 1213 } 1214 } 1215 1216 align = ALIGN(crypto_aead_blocksize(aead), 4); 1217 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1218 1219 error: 1220 return err; 1221 } 1222 1223 static int esp6_rcv_cb(struct sk_buff *skb, int err) 1224 { 1225 return 0; 1226 } 1227 1228 static const struct xfrm_type esp6_type = { 1229 .owner = THIS_MODULE, 1230 .proto = IPPROTO_ESP, 1231 .flags = XFRM_TYPE_REPLAY_PROT, 1232 .init_state = esp6_init_state, 1233 .destructor = esp6_destroy, 1234 .input = esp6_input, 1235 .output = esp6_output, 1236 }; 1237 1238 static struct xfrm6_protocol esp6_protocol = { 1239 .handler = xfrm6_rcv, 1240 .input_handler = xfrm_input, 1241 .cb_handler = esp6_rcv_cb, 1242 .err_handler = esp6_err, 1243 .priority = 0, 1244 }; 1245 1246 static int __init esp6_init(void) 1247 { 1248 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { 1249 pr_info("%s: can't add xfrm type\n", __func__); 1250 return -EAGAIN; 1251 } 1252 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) { 1253 pr_info("%s: can't add protocol\n", __func__); 1254 xfrm_unregister_type(&esp6_type, AF_INET6); 1255 return -EAGAIN; 1256 } 1257 1258 return 0; 1259 } 1260 1261 static void __exit esp6_fini(void) 1262 { 1263 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0) 1264 pr_info("%s: can't remove protocol\n", __func__); 1265 xfrm_unregister_type(&esp6_type, AF_INET6); 1266 } 1267 1268 module_init(esp6_init); 1269 module_exit(esp6_fini); 1270 1271 MODULE_DESCRIPTION("IPv6 ESP transformation helpers"); 1272 MODULE_LICENSE("GPL"); 1273 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP); 1274