1 // SPDX-License-Identifier: GPL-2.0-only 2 #define pr_fmt(fmt) "IPsec: " fmt 3 4 #include <crypto/aead.h> 5 #include <crypto/authenc.h> 6 #include <linux/err.h> 7 #include <linux/module.h> 8 #include <net/ip.h> 9 #include <net/xfrm.h> 10 #include <net/esp.h> 11 #include <linux/scatterlist.h> 12 #include <linux/kernel.h> 13 #include <linux/pfkeyv2.h> 14 #include <linux/rtnetlink.h> 15 #include <linux/slab.h> 16 #include <linux/spinlock.h> 17 #include <linux/in6.h> 18 #include <net/icmp.h> 19 #include <net/protocol.h> 20 #include <net/udp.h> 21 #include <net/tcp.h> 22 #include <net/espintcp.h> 23 #include <linux/skbuff_ref.h> 24 25 #include <linux/highmem.h> 26 27 struct esp_skb_cb { 28 struct xfrm_skb_cb xfrm; 29 void *tmp; 30 }; 31 32 struct esp_output_extra { 33 __be32 seqhi; 34 u32 esphoff; 35 }; 36 37 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0])) 38 39 /* 40 * Allocate an AEAD request structure with extra space for SG and IV. 41 * 42 * For alignment considerations the IV is placed at the front, followed 43 * by the request and finally the SG list. 44 * 45 * TODO: Use spare space in skb for this where possible. 46 */ 47 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen) 48 { 49 unsigned int len; 50 51 len = extralen; 52 53 len += crypto_aead_ivsize(aead); 54 55 if (len) { 56 len += crypto_aead_alignmask(aead) & 57 ~(crypto_tfm_ctx_alignment() - 1); 58 len = ALIGN(len, crypto_tfm_ctx_alignment()); 59 } 60 61 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead); 62 len = ALIGN(len, __alignof__(struct scatterlist)); 63 64 len += sizeof(struct scatterlist) * nfrags; 65 66 return kmalloc(len, GFP_ATOMIC); 67 } 68 69 static inline void *esp_tmp_extra(void *tmp) 70 { 71 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra)); 72 } 73 74 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen) 75 { 76 return crypto_aead_ivsize(aead) ? 77 PTR_ALIGN((u8 *)tmp + extralen, 78 crypto_aead_alignmask(aead) + 1) : tmp + extralen; 79 } 80 81 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv) 82 { 83 struct aead_request *req; 84 85 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead), 86 crypto_tfm_ctx_alignment()); 87 aead_request_set_tfm(req, aead); 88 return req; 89 } 90 91 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead, 92 struct aead_request *req) 93 { 94 return (void *)ALIGN((unsigned long)(req + 1) + 95 crypto_aead_reqsize(aead), 96 __alignof__(struct scatterlist)); 97 } 98 99 static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb) 100 { 101 struct crypto_aead *aead = x->data; 102 int extralen = 0; 103 u8 *iv; 104 struct aead_request *req; 105 struct scatterlist *sg; 106 107 if (x->props.flags & XFRM_STATE_ESN) 108 extralen += sizeof(struct esp_output_extra); 109 110 iv = esp_tmp_iv(aead, tmp, extralen); 111 req = esp_tmp_req(aead, iv); 112 113 /* Unref skb_frag_pages in the src scatterlist if necessary. 114 * Skip the first sg which comes from skb->data. 115 */ 116 if (req->src != req->dst) 117 for (sg = sg_next(req->src); sg; sg = sg_next(sg)) 118 skb_page_unref(page_to_netmem(sg_page(sg)), 119 skb->pp_recycle); 120 } 121 122 #ifdef CONFIG_INET_ESPINTCP 123 static struct sock *esp_find_tcp_sk(struct xfrm_state *x) 124 { 125 struct xfrm_encap_tmpl *encap = x->encap; 126 struct net *net = xs_net(x); 127 __be16 sport, dport; 128 struct sock *sk; 129 130 spin_lock_bh(&x->lock); 131 sport = encap->encap_sport; 132 dport = encap->encap_dport; 133 spin_unlock_bh(&x->lock); 134 135 sk = inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, x->id.daddr.a4, 136 dport, x->props.saddr.a4, sport, 0); 137 if (!sk) 138 return ERR_PTR(-ENOENT); 139 140 if (!tcp_is_ulp_esp(sk)) { 141 sock_put(sk); 142 return ERR_PTR(-EINVAL); 143 } 144 145 return sk; 146 } 147 148 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) 149 { 150 struct sock *sk; 151 int err; 152 153 rcu_read_lock(); 154 155 sk = esp_find_tcp_sk(x); 156 err = PTR_ERR_OR_ZERO(sk); 157 if (err) { 158 kfree_skb(skb); 159 goto out; 160 } 161 162 bh_lock_sock(sk); 163 if (sock_owned_by_user(sk)) 164 err = espintcp_queue_out(sk, skb); 165 else 166 err = espintcp_push_skb(sk, skb); 167 bh_unlock_sock(sk); 168 169 sock_put(sk); 170 171 out: 172 rcu_read_unlock(); 173 return err; 174 } 175 176 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk, 177 struct sk_buff *skb) 178 { 179 struct dst_entry *dst = skb_dst(skb); 180 struct xfrm_state *x = dst->xfrm; 181 182 return esp_output_tcp_finish(x, skb); 183 } 184 185 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 186 { 187 int err; 188 189 local_bh_disable(); 190 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb); 191 local_bh_enable(); 192 193 /* EINPROGRESS just happens to do the right thing. It 194 * actually means that the skb has been consumed and 195 * isn't coming back. 196 */ 197 return err ?: -EINPROGRESS; 198 } 199 #else 200 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 201 { 202 WARN_ON(1); 203 return -EOPNOTSUPP; 204 } 205 #endif 206 207 static void esp_output_done(void *data, int err) 208 { 209 struct sk_buff *skb = data; 210 struct xfrm_offload *xo = xfrm_offload(skb); 211 void *tmp; 212 struct xfrm_state *x; 213 214 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 215 struct sec_path *sp = skb_sec_path(skb); 216 217 x = sp->xvec[sp->len - 1]; 218 } else { 219 x = skb_dst(skb)->xfrm; 220 } 221 222 tmp = ESP_SKB_CB(skb)->tmp; 223 esp_ssg_unref(x, tmp, skb); 224 kfree(tmp); 225 226 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 227 if (err) { 228 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR); 229 kfree_skb(skb); 230 return; 231 } 232 233 skb_push(skb, skb->data - skb_mac_header(skb)); 234 secpath_reset(skb); 235 xfrm_dev_resume(skb); 236 } else { 237 if (!err && 238 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 239 esp_output_tail_tcp(x, skb); 240 else 241 xfrm_output_resume(skb_to_full_sk(skb), skb, err); 242 } 243 } 244 245 /* Move ESP header back into place. */ 246 static void esp_restore_header(struct sk_buff *skb, unsigned int offset) 247 { 248 struct ip_esp_hdr *esph = (void *)(skb->data + offset); 249 void *tmp = ESP_SKB_CB(skb)->tmp; 250 __be32 *seqhi = esp_tmp_extra(tmp); 251 252 esph->seq_no = esph->spi; 253 esph->spi = *seqhi; 254 } 255 256 static void esp_output_restore_header(struct sk_buff *skb) 257 { 258 void *tmp = ESP_SKB_CB(skb)->tmp; 259 struct esp_output_extra *extra = esp_tmp_extra(tmp); 260 261 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff - 262 sizeof(__be32)); 263 } 264 265 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb, 266 struct xfrm_state *x, 267 struct ip_esp_hdr *esph, 268 struct esp_output_extra *extra) 269 { 270 /* For ESN we move the header forward by 4 bytes to 271 * accommodate the high bits. We will move it back after 272 * encryption. 273 */ 274 if ((x->props.flags & XFRM_STATE_ESN)) { 275 __u32 seqhi; 276 struct xfrm_offload *xo = xfrm_offload(skb); 277 278 if (xo) 279 seqhi = xo->seq.hi; 280 else 281 seqhi = XFRM_SKB_CB(skb)->seq.output.hi; 282 283 extra->esphoff = (unsigned char *)esph - 284 skb_transport_header(skb); 285 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4); 286 extra->seqhi = esph->spi; 287 esph->seq_no = htonl(seqhi); 288 } 289 290 esph->spi = x->id.spi; 291 292 return esph; 293 } 294 295 static void esp_output_done_esn(void *data, int err) 296 { 297 struct sk_buff *skb = data; 298 299 esp_output_restore_header(skb); 300 esp_output_done(data, err); 301 } 302 303 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb, 304 int encap_type, 305 struct esp_info *esp, 306 __be16 sport, 307 __be16 dport) 308 { 309 struct udphdr *uh; 310 unsigned int len; 311 struct xfrm_offload *xo = xfrm_offload(skb); 312 313 len = skb->len + esp->tailen - skb_transport_offset(skb); 314 if (len + sizeof(struct iphdr) > IP_MAX_MTU) 315 return ERR_PTR(-EMSGSIZE); 316 317 uh = (struct udphdr *)esp->esph; 318 uh->source = sport; 319 uh->dest = dport; 320 uh->len = htons(len); 321 uh->check = 0; 322 323 /* For IPv4 ESP with UDP encapsulation, if xo is not null, the skb is in the crypto offload 324 * data path, which means that esp_output_udp_encap is called outside of the XFRM stack. 325 * In this case, the mac header doesn't point to the IPv4 protocol field, so don't set it. 326 */ 327 if (!xo || encap_type != UDP_ENCAP_ESPINUDP) 328 *skb_mac_header(skb) = IPPROTO_UDP; 329 330 return (struct ip_esp_hdr *)(uh + 1); 331 } 332 333 #ifdef CONFIG_INET_ESPINTCP 334 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 335 struct sk_buff *skb, 336 struct esp_info *esp) 337 { 338 __be16 *lenp = (void *)esp->esph; 339 struct ip_esp_hdr *esph; 340 unsigned int len; 341 struct sock *sk; 342 343 len = skb->len + esp->tailen - skb_transport_offset(skb); 344 if (len > IP_MAX_MTU) 345 return ERR_PTR(-EMSGSIZE); 346 347 rcu_read_lock(); 348 sk = esp_find_tcp_sk(x); 349 rcu_read_unlock(); 350 351 if (IS_ERR(sk)) 352 return ERR_CAST(sk); 353 354 sock_put(sk); 355 356 *lenp = htons(len); 357 esph = (struct ip_esp_hdr *)(lenp + 1); 358 359 return esph; 360 } 361 #else 362 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 363 struct sk_buff *skb, 364 struct esp_info *esp) 365 { 366 return ERR_PTR(-EOPNOTSUPP); 367 } 368 #endif 369 370 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb, 371 struct esp_info *esp) 372 { 373 struct xfrm_encap_tmpl *encap = x->encap; 374 struct ip_esp_hdr *esph; 375 __be16 sport, dport; 376 int encap_type; 377 378 spin_lock_bh(&x->lock); 379 sport = encap->encap_sport; 380 dport = encap->encap_dport; 381 encap_type = encap->encap_type; 382 spin_unlock_bh(&x->lock); 383 384 switch (encap_type) { 385 default: 386 case UDP_ENCAP_ESPINUDP: 387 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport); 388 break; 389 case TCP_ENCAP_ESPINTCP: 390 esph = esp_output_tcp_encap(x, skb, esp); 391 break; 392 } 393 394 if (IS_ERR(esph)) 395 return PTR_ERR(esph); 396 397 esp->esph = esph; 398 399 return 0; 400 } 401 402 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 403 { 404 u8 *tail; 405 int nfrags; 406 int esph_offset; 407 struct page *page; 408 struct sk_buff *trailer; 409 int tailen = esp->tailen; 410 411 /* this is non-NULL only with TCP/UDP Encapsulation */ 412 if (x->encap) { 413 int err = esp_output_encap(x, skb, esp); 414 415 if (err < 0) 416 return err; 417 } 418 419 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE || 420 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE) 421 goto cow; 422 423 if (!skb_cloned(skb)) { 424 if (tailen <= skb_tailroom(skb)) { 425 nfrags = 1; 426 trailer = skb; 427 tail = skb_tail_pointer(trailer); 428 429 goto skip_cow; 430 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 431 && !skb_has_frag_list(skb)) { 432 int allocsize; 433 struct sock *sk = skb->sk; 434 struct page_frag *pfrag = &x->xfrag; 435 436 esp->inplace = false; 437 438 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 439 440 spin_lock_bh(&x->lock); 441 442 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 443 spin_unlock_bh(&x->lock); 444 goto cow; 445 } 446 447 page = pfrag->page; 448 get_page(page); 449 450 tail = page_address(page) + pfrag->offset; 451 452 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 453 454 nfrags = skb_shinfo(skb)->nr_frags; 455 456 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 457 tailen); 458 skb_shinfo(skb)->nr_frags = ++nfrags; 459 460 pfrag->offset = pfrag->offset + allocsize; 461 462 spin_unlock_bh(&x->lock); 463 464 nfrags++; 465 466 skb_len_add(skb, tailen); 467 if (sk && sk_fullsock(sk)) 468 refcount_add(tailen, &sk->sk_wmem_alloc); 469 470 goto out; 471 } 472 } 473 474 cow: 475 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 476 477 nfrags = skb_cow_data(skb, tailen, &trailer); 478 if (nfrags < 0) 479 goto out; 480 tail = skb_tail_pointer(trailer); 481 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 482 483 skip_cow: 484 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 485 pskb_put(skb, trailer, tailen); 486 487 out: 488 return nfrags; 489 } 490 EXPORT_SYMBOL_GPL(esp_output_head); 491 492 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 493 { 494 u8 *iv; 495 int alen; 496 void *tmp; 497 int ivlen; 498 int assoclen; 499 int extralen; 500 struct page *page; 501 struct ip_esp_hdr *esph; 502 struct crypto_aead *aead; 503 struct aead_request *req; 504 struct scatterlist *sg, *dsg; 505 struct esp_output_extra *extra; 506 int err = -ENOMEM; 507 508 assoclen = sizeof(struct ip_esp_hdr); 509 extralen = 0; 510 511 if (x->props.flags & XFRM_STATE_ESN) { 512 extralen += sizeof(*extra); 513 assoclen += sizeof(__be32); 514 } 515 516 aead = x->data; 517 alen = crypto_aead_authsize(aead); 518 ivlen = crypto_aead_ivsize(aead); 519 520 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 521 if (!tmp) 522 goto error; 523 524 extra = esp_tmp_extra(tmp); 525 iv = esp_tmp_iv(aead, tmp, extralen); 526 req = esp_tmp_req(aead, iv); 527 sg = esp_req_sg(aead, req); 528 529 if (esp->inplace) 530 dsg = sg; 531 else 532 dsg = &sg[esp->nfrags]; 533 534 esph = esp_output_set_extra(skb, x, esp->esph, extra); 535 esp->esph = esph; 536 537 sg_init_table(sg, esp->nfrags); 538 err = skb_to_sgvec(skb, sg, 539 (unsigned char *)esph - skb->data, 540 assoclen + ivlen + esp->clen + alen); 541 if (unlikely(err < 0)) 542 goto error_free; 543 544 if (!esp->inplace) { 545 int allocsize; 546 struct page_frag *pfrag = &x->xfrag; 547 548 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 549 550 spin_lock_bh(&x->lock); 551 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 552 spin_unlock_bh(&x->lock); 553 goto error_free; 554 } 555 556 skb_shinfo(skb)->nr_frags = 1; 557 558 page = pfrag->page; 559 get_page(page); 560 /* replace page frags in skb with new page */ 561 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 562 pfrag->offset = pfrag->offset + allocsize; 563 spin_unlock_bh(&x->lock); 564 565 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 566 err = skb_to_sgvec(skb, dsg, 567 (unsigned char *)esph - skb->data, 568 assoclen + ivlen + esp->clen + alen); 569 if (unlikely(err < 0)) 570 goto error_free; 571 } 572 573 if ((x->props.flags & XFRM_STATE_ESN)) 574 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 575 else 576 aead_request_set_callback(req, 0, esp_output_done, skb); 577 578 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 579 aead_request_set_ad(req, assoclen); 580 581 memset(iv, 0, ivlen); 582 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 583 min(ivlen, 8)); 584 585 ESP_SKB_CB(skb)->tmp = tmp; 586 err = crypto_aead_encrypt(req); 587 588 switch (err) { 589 case -EINPROGRESS: 590 goto error; 591 592 case -ENOSPC: 593 err = NET_XMIT_DROP; 594 break; 595 596 case 0: 597 if ((x->props.flags & XFRM_STATE_ESN)) 598 esp_output_restore_header(skb); 599 } 600 601 if (sg != dsg) 602 esp_ssg_unref(x, tmp, skb); 603 604 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 605 err = esp_output_tail_tcp(x, skb); 606 607 error_free: 608 kfree(tmp); 609 error: 610 return err; 611 } 612 EXPORT_SYMBOL_GPL(esp_output_tail); 613 614 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 615 { 616 int alen; 617 int blksize; 618 struct ip_esp_hdr *esph; 619 struct crypto_aead *aead; 620 struct esp_info esp; 621 622 esp.inplace = true; 623 624 esp.proto = *skb_mac_header(skb); 625 *skb_mac_header(skb) = IPPROTO_ESP; 626 627 /* skb is pure payload to encrypt */ 628 629 aead = x->data; 630 alen = crypto_aead_authsize(aead); 631 632 esp.tfclen = 0; 633 if (x->tfcpad) { 634 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 635 u32 padto; 636 637 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 638 if (skb->len < padto) 639 esp.tfclen = padto - skb->len; 640 } 641 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 642 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 643 esp.plen = esp.clen - skb->len - esp.tfclen; 644 esp.tailen = esp.tfclen + esp.plen + alen; 645 646 esp.esph = ip_esp_hdr(skb); 647 648 esp.nfrags = esp_output_head(x, skb, &esp); 649 if (esp.nfrags < 0) 650 return esp.nfrags; 651 652 esph = esp.esph; 653 esph->spi = x->id.spi; 654 655 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 656 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 657 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 658 659 skb_push(skb, -skb_network_offset(skb)); 660 661 return esp_output_tail(x, skb, &esp); 662 } 663 664 static inline int esp_remove_trailer(struct sk_buff *skb) 665 { 666 struct xfrm_state *x = xfrm_input_state(skb); 667 struct crypto_aead *aead = x->data; 668 int alen, hlen, elen; 669 int padlen, trimlen; 670 __wsum csumdiff; 671 u8 nexthdr[2]; 672 int ret; 673 674 alen = crypto_aead_authsize(aead); 675 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 676 elen = skb->len - hlen; 677 678 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) 679 BUG(); 680 681 ret = -EINVAL; 682 padlen = nexthdr[0]; 683 if (padlen + 2 + alen >= elen) { 684 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 685 padlen + 2, elen - alen); 686 goto out; 687 } 688 689 trimlen = alen + padlen + 2; 690 if (skb->ip_summed == CHECKSUM_COMPLETE) { 691 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 692 skb->csum = csum_block_sub(skb->csum, csumdiff, 693 skb->len - trimlen); 694 } 695 ret = pskb_trim(skb, skb->len - trimlen); 696 if (unlikely(ret)) 697 return ret; 698 699 ret = nexthdr[1]; 700 701 out: 702 return ret; 703 } 704 705 int esp_input_done2(struct sk_buff *skb, int err) 706 { 707 const struct iphdr *iph; 708 struct xfrm_state *x = xfrm_input_state(skb); 709 struct xfrm_offload *xo = xfrm_offload(skb); 710 struct crypto_aead *aead = x->data; 711 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 712 int ihl; 713 714 if (!xo || !(xo->flags & CRYPTO_DONE)) 715 kfree(ESP_SKB_CB(skb)->tmp); 716 717 if (unlikely(err)) 718 goto out; 719 720 err = esp_remove_trailer(skb); 721 if (unlikely(err < 0)) 722 goto out; 723 724 iph = ip_hdr(skb); 725 ihl = iph->ihl * 4; 726 727 if (x->encap) { 728 struct xfrm_encap_tmpl *encap = x->encap; 729 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl); 730 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 731 __be16 source; 732 733 switch (x->encap->encap_type) { 734 case TCP_ENCAP_ESPINTCP: 735 source = th->source; 736 break; 737 case UDP_ENCAP_ESPINUDP: 738 source = uh->source; 739 break; 740 default: 741 WARN_ON_ONCE(1); 742 err = -EINVAL; 743 goto out; 744 } 745 746 /* 747 * 1) if the NAT-T peer's IP or port changed then 748 * advertise the change to the keying daemon. 749 * This is an inbound SA, so just compare 750 * SRC ports. 751 */ 752 if (iph->saddr != x->props.saddr.a4 || 753 source != encap->encap_sport) { 754 xfrm_address_t ipaddr; 755 756 ipaddr.a4 = iph->saddr; 757 km_new_mapping(x, &ipaddr, source); 758 759 /* XXX: perhaps add an extra 760 * policy check here, to see 761 * if we should allow or 762 * reject a packet from a 763 * different source 764 * address/port. 765 */ 766 } 767 768 /* 769 * 2) ignore UDP/TCP checksums in case 770 * of NAT-T in Transport Mode, or 771 * perform other post-processing fixes 772 * as per draft-ietf-ipsec-udp-encaps-06, 773 * section 3.1.2 774 */ 775 if (x->props.mode == XFRM_MODE_TRANSPORT) 776 skb->ip_summed = CHECKSUM_UNNECESSARY; 777 } 778 779 skb_pull_rcsum(skb, hlen); 780 if (x->props.mode == XFRM_MODE_TUNNEL || 781 x->props.mode == XFRM_MODE_IPTFS) 782 skb_reset_transport_header(skb); 783 else 784 skb_set_transport_header(skb, -ihl); 785 786 /* RFC4303: Drop dummy packets without any error */ 787 if (err == IPPROTO_NONE) 788 err = -EINVAL; 789 790 out: 791 return err; 792 } 793 EXPORT_SYMBOL_GPL(esp_input_done2); 794 795 static void esp_input_done(void *data, int err) 796 { 797 struct sk_buff *skb = data; 798 799 xfrm_input_resume(skb, esp_input_done2(skb, err)); 800 } 801 802 static void esp_input_restore_header(struct sk_buff *skb) 803 { 804 esp_restore_header(skb, 0); 805 __skb_pull(skb, 4); 806 } 807 808 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 809 { 810 struct xfrm_state *x = xfrm_input_state(skb); 811 struct ip_esp_hdr *esph; 812 813 /* For ESN we move the header forward by 4 bytes to 814 * accommodate the high bits. We will move it back after 815 * decryption. 816 */ 817 if ((x->props.flags & XFRM_STATE_ESN)) { 818 esph = skb_push(skb, 4); 819 *seqhi = esph->spi; 820 esph->spi = esph->seq_no; 821 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 822 } 823 } 824 825 static void esp_input_done_esn(void *data, int err) 826 { 827 struct sk_buff *skb = data; 828 829 esp_input_restore_header(skb); 830 esp_input_done(data, err); 831 } 832 833 /* 834 * Note: detecting truncated vs. non-truncated authentication data is very 835 * expensive, so we only support truncated data, which is the recommended 836 * and common case. 837 */ 838 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 839 { 840 struct crypto_aead *aead = x->data; 841 struct aead_request *req; 842 struct sk_buff *trailer; 843 int ivlen = crypto_aead_ivsize(aead); 844 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 845 int nfrags; 846 int assoclen; 847 int seqhilen; 848 __be32 *seqhi; 849 void *tmp; 850 u8 *iv; 851 struct scatterlist *sg; 852 int err = -EINVAL; 853 854 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) 855 goto out; 856 857 if (elen <= 0) 858 goto out; 859 860 assoclen = sizeof(struct ip_esp_hdr); 861 seqhilen = 0; 862 863 if (x->props.flags & XFRM_STATE_ESN) { 864 seqhilen += sizeof(__be32); 865 assoclen += seqhilen; 866 } 867 868 if (!skb_cloned(skb)) { 869 if (!skb_is_nonlinear(skb)) { 870 nfrags = 1; 871 872 goto skip_cow; 873 } else if (!skb_has_frag_list(skb)) { 874 nfrags = skb_shinfo(skb)->nr_frags; 875 nfrags++; 876 877 goto skip_cow; 878 } 879 } 880 881 err = skb_cow_data(skb, 0, &trailer); 882 if (err < 0) 883 goto out; 884 885 nfrags = err; 886 887 skip_cow: 888 err = -ENOMEM; 889 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 890 if (!tmp) 891 goto out; 892 893 ESP_SKB_CB(skb)->tmp = tmp; 894 seqhi = esp_tmp_extra(tmp); 895 iv = esp_tmp_iv(aead, tmp, seqhilen); 896 req = esp_tmp_req(aead, iv); 897 sg = esp_req_sg(aead, req); 898 899 esp_input_set_header(skb, seqhi); 900 901 sg_init_table(sg, nfrags); 902 err = skb_to_sgvec(skb, sg, 0, skb->len); 903 if (unlikely(err < 0)) { 904 kfree(tmp); 905 goto out; 906 } 907 908 skb->ip_summed = CHECKSUM_NONE; 909 910 if ((x->props.flags & XFRM_STATE_ESN)) 911 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 912 else 913 aead_request_set_callback(req, 0, esp_input_done, skb); 914 915 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 916 aead_request_set_ad(req, assoclen); 917 918 err = crypto_aead_decrypt(req); 919 if (err == -EINPROGRESS) 920 goto out; 921 922 if ((x->props.flags & XFRM_STATE_ESN)) 923 esp_input_restore_header(skb); 924 925 err = esp_input_done2(skb, err); 926 927 out: 928 return err; 929 } 930 931 static int esp4_err(struct sk_buff *skb, u32 info) 932 { 933 struct net *net = dev_net(skb->dev); 934 const struct iphdr *iph = (const struct iphdr *)skb->data; 935 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 936 struct xfrm_state *x; 937 938 switch (icmp_hdr(skb)->type) { 939 case ICMP_DEST_UNREACH: 940 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 941 return 0; 942 break; 943 case ICMP_REDIRECT: 944 break; 945 default: 946 return 0; 947 } 948 949 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 950 esph->spi, IPPROTO_ESP, AF_INET); 951 if (!x) 952 return 0; 953 954 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 955 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP); 956 else 957 ipv4_redirect(skb, net, 0, IPPROTO_ESP); 958 xfrm_state_put(x); 959 960 return 0; 961 } 962 963 static void esp_destroy(struct xfrm_state *x) 964 { 965 struct crypto_aead *aead = x->data; 966 967 if (!aead) 968 return; 969 970 crypto_free_aead(aead); 971 } 972 973 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 974 { 975 char aead_name[CRYPTO_MAX_ALG_NAME]; 976 struct crypto_aead *aead; 977 int err; 978 979 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 980 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 981 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 982 return -ENAMETOOLONG; 983 } 984 985 aead = crypto_alloc_aead(aead_name, 0, 0); 986 err = PTR_ERR(aead); 987 if (IS_ERR(aead)) 988 goto error; 989 990 x->data = aead; 991 992 err = crypto_aead_setkey(aead, x->aead->alg_key, 993 (x->aead->alg_key_len + 7) / 8); 994 if (err) 995 goto error; 996 997 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 998 if (err) 999 goto error; 1000 1001 return 0; 1002 1003 error: 1004 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1005 return err; 1006 } 1007 1008 static int esp_init_authenc(struct xfrm_state *x, 1009 struct netlink_ext_ack *extack) 1010 { 1011 struct crypto_aead *aead; 1012 struct crypto_authenc_key_param *param; 1013 struct rtattr *rta; 1014 char *key; 1015 char *p; 1016 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1017 unsigned int keylen; 1018 int err; 1019 1020 err = -ENAMETOOLONG; 1021 1022 if ((x->props.flags & XFRM_STATE_ESN)) { 1023 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1024 "%s%sauthencesn(%s,%s)%s", 1025 x->geniv ?: "", x->geniv ? "(" : "", 1026 x->aalg ? x->aalg->alg_name : "digest_null", 1027 x->ealg->alg_name, 1028 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1029 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1030 goto error; 1031 } 1032 } else { 1033 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1034 "%s%sauthenc(%s,%s)%s", 1035 x->geniv ?: "", x->geniv ? "(" : "", 1036 x->aalg ? x->aalg->alg_name : "digest_null", 1037 x->ealg->alg_name, 1038 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1039 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1040 goto error; 1041 } 1042 } 1043 1044 aead = crypto_alloc_aead(authenc_name, 0, 0); 1045 err = PTR_ERR(aead); 1046 if (IS_ERR(aead)) { 1047 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1048 goto error; 1049 } 1050 1051 x->data = aead; 1052 1053 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1054 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1055 err = -ENOMEM; 1056 key = kmalloc(keylen, GFP_KERNEL); 1057 if (!key) 1058 goto error; 1059 1060 p = key; 1061 rta = (void *)p; 1062 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1063 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1064 param = RTA_DATA(rta); 1065 p += RTA_SPACE(sizeof(*param)); 1066 1067 if (x->aalg) { 1068 struct xfrm_algo_desc *aalg_desc; 1069 1070 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1071 p += (x->aalg->alg_key_len + 7) / 8; 1072 1073 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1074 BUG_ON(!aalg_desc); 1075 1076 err = -EINVAL; 1077 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1078 crypto_aead_authsize(aead)) { 1079 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1080 goto free_key; 1081 } 1082 1083 err = crypto_aead_setauthsize( 1084 aead, x->aalg->alg_trunc_len / 8); 1085 if (err) { 1086 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1087 goto free_key; 1088 } 1089 } 1090 1091 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1092 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1093 1094 err = crypto_aead_setkey(aead, key, keylen); 1095 1096 free_key: 1097 kfree_sensitive(key); 1098 1099 error: 1100 return err; 1101 } 1102 1103 static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1104 { 1105 struct crypto_aead *aead; 1106 u32 align; 1107 int err; 1108 1109 x->data = NULL; 1110 1111 if (x->aead) { 1112 err = esp_init_aead(x, extack); 1113 } else if (x->ealg) { 1114 err = esp_init_authenc(x, extack); 1115 } else { 1116 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1117 err = -EINVAL; 1118 } 1119 1120 if (err) 1121 goto error; 1122 1123 aead = x->data; 1124 1125 x->props.header_len = sizeof(struct ip_esp_hdr) + 1126 crypto_aead_ivsize(aead); 1127 if (x->props.mode == XFRM_MODE_TUNNEL) 1128 x->props.header_len += sizeof(struct iphdr); 1129 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 1130 x->props.header_len += IPV4_BEET_PHMAXLEN; 1131 if (x->encap) { 1132 struct xfrm_encap_tmpl *encap = x->encap; 1133 1134 switch (encap->encap_type) { 1135 default: 1136 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1137 err = -EINVAL; 1138 goto error; 1139 case UDP_ENCAP_ESPINUDP: 1140 x->props.header_len += sizeof(struct udphdr); 1141 break; 1142 #ifdef CONFIG_INET_ESPINTCP 1143 case TCP_ENCAP_ESPINTCP: 1144 /* only the length field, TCP encap is done by 1145 * the socket 1146 */ 1147 x->props.header_len += 2; 1148 break; 1149 #endif 1150 } 1151 } 1152 1153 align = ALIGN(crypto_aead_blocksize(aead), 4); 1154 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1155 1156 error: 1157 return err; 1158 } 1159 1160 static int esp4_rcv_cb(struct sk_buff *skb, int err) 1161 { 1162 return 0; 1163 } 1164 1165 static const struct xfrm_type esp_type = 1166 { 1167 .owner = THIS_MODULE, 1168 .proto = IPPROTO_ESP, 1169 .flags = XFRM_TYPE_REPLAY_PROT, 1170 .init_state = esp_init_state, 1171 .destructor = esp_destroy, 1172 .input = esp_input, 1173 .output = esp_output, 1174 }; 1175 1176 static struct xfrm4_protocol esp4_protocol = { 1177 .handler = xfrm4_rcv, 1178 .input_handler = xfrm_input, 1179 .cb_handler = esp4_rcv_cb, 1180 .err_handler = esp4_err, 1181 .priority = 0, 1182 }; 1183 1184 static int __init esp4_init(void) 1185 { 1186 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 1187 pr_info("%s: can't add xfrm type\n", __func__); 1188 return -EAGAIN; 1189 } 1190 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 1191 pr_info("%s: can't add protocol\n", __func__); 1192 xfrm_unregister_type(&esp_type, AF_INET); 1193 return -EAGAIN; 1194 } 1195 return 0; 1196 } 1197 1198 static void __exit esp4_fini(void) 1199 { 1200 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 1201 pr_info("%s: can't remove protocol\n", __func__); 1202 xfrm_unregister_type(&esp_type, AF_INET); 1203 } 1204 1205 module_init(esp4_init); 1206 module_exit(esp4_fini); 1207 MODULE_DESCRIPTION("IPv4 ESP transformation library"); 1208 MODULE_LICENSE("GPL"); 1209 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1210