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, x->id.daddr.a4, dport, 136 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 err = esp_output_tail_tcp(x, skb); 240 if (err != -EINPROGRESS) 241 kfree_skb(skb); 242 } else { 243 xfrm_output_resume(skb_to_full_sk(skb), skb, err); 244 } 245 } 246 } 247 248 /* Move ESP header back into place. */ 249 static void esp_restore_header(struct sk_buff *skb, unsigned int offset) 250 { 251 struct ip_esp_hdr *esph = (void *)(skb->data + offset); 252 void *tmp = ESP_SKB_CB(skb)->tmp; 253 __be32 *seqhi = esp_tmp_extra(tmp); 254 255 esph->seq_no = esph->spi; 256 esph->spi = *seqhi; 257 } 258 259 static void esp_output_restore_header(struct sk_buff *skb) 260 { 261 void *tmp = ESP_SKB_CB(skb)->tmp; 262 struct esp_output_extra *extra = esp_tmp_extra(tmp); 263 264 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff - 265 sizeof(__be32)); 266 } 267 268 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb, 269 struct xfrm_state *x, 270 struct ip_esp_hdr *esph, 271 struct esp_output_extra *extra) 272 { 273 /* For ESN we move the header forward by 4 bytes to 274 * accommodate the high bits. We will move it back after 275 * encryption. 276 */ 277 if ((x->props.flags & XFRM_STATE_ESN)) { 278 __u32 seqhi; 279 struct xfrm_offload *xo = xfrm_offload(skb); 280 281 if (xo) 282 seqhi = xo->seq.hi; 283 else 284 seqhi = XFRM_SKB_CB(skb)->seq.output.hi; 285 286 extra->esphoff = (unsigned char *)esph - 287 skb_transport_header(skb); 288 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4); 289 extra->seqhi = esph->spi; 290 esph->seq_no = htonl(seqhi); 291 } 292 293 esph->spi = x->id.spi; 294 295 return esph; 296 } 297 298 static void esp_output_done_esn(void *data, int err) 299 { 300 struct sk_buff *skb = data; 301 302 esp_output_restore_header(skb); 303 esp_output_done(data, err); 304 } 305 306 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb, 307 int encap_type, 308 struct esp_info *esp, 309 __be16 sport, 310 __be16 dport) 311 { 312 struct udphdr *uh; 313 unsigned int len; 314 struct xfrm_offload *xo = xfrm_offload(skb); 315 316 len = skb->len + esp->tailen - skb_transport_offset(skb); 317 if (len + sizeof(struct iphdr) > IP_MAX_MTU) 318 return ERR_PTR(-EMSGSIZE); 319 320 uh = (struct udphdr *)esp->esph; 321 uh->source = sport; 322 uh->dest = dport; 323 uh->len = htons(len); 324 uh->check = 0; 325 326 /* For IPv4 ESP with UDP encapsulation, if xo is not null, the skb is in the crypto offload 327 * data path, which means that esp_output_udp_encap is called outside of the XFRM stack. 328 * In this case, the mac header doesn't point to the IPv4 protocol field, so don't set it. 329 */ 330 if (!xo || encap_type != UDP_ENCAP_ESPINUDP) 331 *skb_mac_header(skb) = IPPROTO_UDP; 332 333 return (struct ip_esp_hdr *)(uh + 1); 334 } 335 336 #ifdef CONFIG_INET_ESPINTCP 337 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 338 struct sk_buff *skb, 339 struct esp_info *esp) 340 { 341 __be16 *lenp = (void *)esp->esph; 342 struct ip_esp_hdr *esph; 343 unsigned int len; 344 struct sock *sk; 345 346 len = skb->len + esp->tailen - skb_transport_offset(skb); 347 if (len > IP_MAX_MTU) 348 return ERR_PTR(-EMSGSIZE); 349 350 rcu_read_lock(); 351 sk = esp_find_tcp_sk(x); 352 rcu_read_unlock(); 353 354 if (IS_ERR(sk)) 355 return ERR_CAST(sk); 356 357 sock_put(sk); 358 359 *lenp = htons(len); 360 esph = (struct ip_esp_hdr *)(lenp + 1); 361 362 return esph; 363 } 364 #else 365 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 366 struct sk_buff *skb, 367 struct esp_info *esp) 368 { 369 return ERR_PTR(-EOPNOTSUPP); 370 } 371 #endif 372 373 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb, 374 struct esp_info *esp) 375 { 376 struct xfrm_encap_tmpl *encap = x->encap; 377 struct ip_esp_hdr *esph; 378 __be16 sport, dport; 379 int encap_type; 380 381 spin_lock_bh(&x->lock); 382 sport = encap->encap_sport; 383 dport = encap->encap_dport; 384 encap_type = encap->encap_type; 385 spin_unlock_bh(&x->lock); 386 387 switch (encap_type) { 388 default: 389 case UDP_ENCAP_ESPINUDP: 390 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport); 391 break; 392 case TCP_ENCAP_ESPINTCP: 393 esph = esp_output_tcp_encap(x, skb, esp); 394 break; 395 } 396 397 if (IS_ERR(esph)) 398 return PTR_ERR(esph); 399 400 esp->esph = esph; 401 402 return 0; 403 } 404 405 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 406 { 407 u8 *tail; 408 int nfrags; 409 int esph_offset; 410 struct page *page; 411 struct sk_buff *trailer; 412 int tailen = esp->tailen; 413 414 /* this is non-NULL only with TCP/UDP Encapsulation */ 415 if (x->encap) { 416 int err = esp_output_encap(x, skb, esp); 417 418 if (err < 0) 419 return err; 420 } 421 422 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE || 423 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE) 424 goto cow; 425 426 if (!skb_cloned(skb)) { 427 if (tailen <= skb_tailroom(skb)) { 428 nfrags = 1; 429 trailer = skb; 430 tail = skb_tail_pointer(trailer); 431 432 goto skip_cow; 433 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 434 && !skb_has_frag_list(skb)) { 435 int allocsize; 436 struct sock *sk = skb->sk; 437 struct page_frag *pfrag = &x->xfrag; 438 439 esp->inplace = false; 440 441 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 442 443 spin_lock_bh(&x->lock); 444 445 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 446 spin_unlock_bh(&x->lock); 447 goto cow; 448 } 449 450 page = pfrag->page; 451 get_page(page); 452 453 tail = page_address(page) + pfrag->offset; 454 455 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 456 457 nfrags = skb_shinfo(skb)->nr_frags; 458 459 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 460 tailen); 461 skb_shinfo(skb)->nr_frags = ++nfrags; 462 463 pfrag->offset = pfrag->offset + allocsize; 464 465 spin_unlock_bh(&x->lock); 466 467 nfrags++; 468 469 skb_len_add(skb, tailen); 470 if (sk && sk_fullsock(sk)) 471 refcount_add(tailen, &sk->sk_wmem_alloc); 472 473 goto out; 474 } 475 } 476 477 cow: 478 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 479 480 nfrags = skb_cow_data(skb, tailen, &trailer); 481 if (nfrags < 0) 482 goto out; 483 tail = skb_tail_pointer(trailer); 484 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 485 486 skip_cow: 487 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 488 pskb_put(skb, trailer, tailen); 489 490 out: 491 return nfrags; 492 } 493 EXPORT_SYMBOL_GPL(esp_output_head); 494 495 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 496 { 497 u8 *iv; 498 int alen; 499 void *tmp; 500 int ivlen; 501 int assoclen; 502 int extralen; 503 struct page *page; 504 struct ip_esp_hdr *esph; 505 struct crypto_aead *aead; 506 struct aead_request *req; 507 struct scatterlist *sg, *dsg; 508 struct esp_output_extra *extra; 509 int err = -ENOMEM; 510 511 assoclen = sizeof(struct ip_esp_hdr); 512 extralen = 0; 513 514 if (x->props.flags & XFRM_STATE_ESN) { 515 extralen += sizeof(*extra); 516 assoclen += sizeof(__be32); 517 } 518 519 aead = x->data; 520 alen = crypto_aead_authsize(aead); 521 ivlen = crypto_aead_ivsize(aead); 522 523 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 524 if (!tmp) 525 goto error; 526 527 extra = esp_tmp_extra(tmp); 528 iv = esp_tmp_iv(aead, tmp, extralen); 529 req = esp_tmp_req(aead, iv); 530 sg = esp_req_sg(aead, req); 531 532 if (esp->inplace) 533 dsg = sg; 534 else 535 dsg = &sg[esp->nfrags]; 536 537 esph = esp_output_set_extra(skb, x, esp->esph, extra); 538 esp->esph = esph; 539 540 sg_init_table(sg, esp->nfrags); 541 err = skb_to_sgvec(skb, sg, 542 (unsigned char *)esph - skb->data, 543 assoclen + ivlen + esp->clen + alen); 544 if (unlikely(err < 0)) 545 goto error_free; 546 547 if (!esp->inplace) { 548 int allocsize; 549 struct page_frag *pfrag = &x->xfrag; 550 551 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 552 553 spin_lock_bh(&x->lock); 554 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 555 spin_unlock_bh(&x->lock); 556 goto error_free; 557 } 558 559 skb_shinfo(skb)->nr_frags = 1; 560 561 page = pfrag->page; 562 get_page(page); 563 /* replace page frags in skb with new page */ 564 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 565 pfrag->offset = pfrag->offset + allocsize; 566 spin_unlock_bh(&x->lock); 567 568 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 569 err = skb_to_sgvec(skb, dsg, 570 (unsigned char *)esph - skb->data, 571 assoclen + ivlen + esp->clen + alen); 572 if (unlikely(err < 0)) 573 goto error_free; 574 } 575 576 if ((x->props.flags & XFRM_STATE_ESN)) 577 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 578 else 579 aead_request_set_callback(req, 0, esp_output_done, skb); 580 581 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 582 aead_request_set_ad(req, assoclen); 583 584 memset(iv, 0, ivlen); 585 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 586 min(ivlen, 8)); 587 588 ESP_SKB_CB(skb)->tmp = tmp; 589 err = crypto_aead_encrypt(req); 590 591 switch (err) { 592 case -EINPROGRESS: 593 goto error; 594 595 case -ENOSPC: 596 err = NET_XMIT_DROP; 597 break; 598 599 case 0: 600 if ((x->props.flags & XFRM_STATE_ESN)) 601 esp_output_restore_header(skb); 602 } 603 604 if (sg != dsg) 605 esp_ssg_unref(x, tmp, skb); 606 607 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 608 err = esp_output_tail_tcp(x, skb); 609 610 error_free: 611 kfree(tmp); 612 error: 613 return err; 614 } 615 EXPORT_SYMBOL_GPL(esp_output_tail); 616 617 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 618 { 619 int alen; 620 int blksize; 621 struct ip_esp_hdr *esph; 622 struct crypto_aead *aead; 623 struct esp_info esp; 624 625 esp.inplace = true; 626 627 esp.proto = *skb_mac_header(skb); 628 *skb_mac_header(skb) = IPPROTO_ESP; 629 630 /* skb is pure payload to encrypt */ 631 632 aead = x->data; 633 alen = crypto_aead_authsize(aead); 634 635 esp.tfclen = 0; 636 if (x->tfcpad) { 637 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 638 u32 padto; 639 640 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 641 if (skb->len < padto) 642 esp.tfclen = padto - skb->len; 643 } 644 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 645 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 646 esp.plen = esp.clen - skb->len - esp.tfclen; 647 esp.tailen = esp.tfclen + esp.plen + alen; 648 649 esp.esph = ip_esp_hdr(skb); 650 651 esp.nfrags = esp_output_head(x, skb, &esp); 652 if (esp.nfrags < 0) 653 return esp.nfrags; 654 655 esph = esp.esph; 656 esph->spi = x->id.spi; 657 658 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 659 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 660 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 661 662 skb_push(skb, -skb_network_offset(skb)); 663 664 return esp_output_tail(x, skb, &esp); 665 } 666 667 static inline int esp_remove_trailer(struct sk_buff *skb) 668 { 669 struct xfrm_state *x = xfrm_input_state(skb); 670 struct crypto_aead *aead = x->data; 671 int alen, hlen, elen; 672 int padlen, trimlen; 673 __wsum csumdiff; 674 u8 nexthdr[2]; 675 int ret; 676 677 alen = crypto_aead_authsize(aead); 678 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 679 elen = skb->len - hlen; 680 681 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) 682 BUG(); 683 684 ret = -EINVAL; 685 padlen = nexthdr[0]; 686 if (padlen + 2 + alen >= elen) { 687 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 688 padlen + 2, elen - alen); 689 goto out; 690 } 691 692 trimlen = alen + padlen + 2; 693 if (skb->ip_summed == CHECKSUM_COMPLETE) { 694 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 695 skb->csum = csum_block_sub(skb->csum, csumdiff, 696 skb->len - trimlen); 697 } 698 ret = pskb_trim(skb, skb->len - trimlen); 699 if (unlikely(ret)) 700 return ret; 701 702 ret = nexthdr[1]; 703 704 out: 705 return ret; 706 } 707 708 int esp_input_done2(struct sk_buff *skb, int err) 709 { 710 const struct iphdr *iph; 711 struct xfrm_state *x = xfrm_input_state(skb); 712 struct xfrm_offload *xo = xfrm_offload(skb); 713 struct crypto_aead *aead = x->data; 714 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 715 int ihl; 716 717 if (!xo || !(xo->flags & CRYPTO_DONE)) 718 kfree(ESP_SKB_CB(skb)->tmp); 719 720 if (unlikely(err)) 721 goto out; 722 723 err = esp_remove_trailer(skb); 724 if (unlikely(err < 0)) 725 goto out; 726 727 iph = ip_hdr(skb); 728 ihl = iph->ihl * 4; 729 730 if (x->encap) { 731 struct xfrm_encap_tmpl *encap = x->encap; 732 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl); 733 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 734 __be16 source; 735 736 switch (x->encap->encap_type) { 737 case TCP_ENCAP_ESPINTCP: 738 source = th->source; 739 break; 740 case UDP_ENCAP_ESPINUDP: 741 source = uh->source; 742 break; 743 default: 744 WARN_ON_ONCE(1); 745 err = -EINVAL; 746 goto out; 747 } 748 749 /* 750 * 1) if the NAT-T peer's IP or port changed then 751 * advertise the change to the keying daemon. 752 * This is an inbound SA, so just compare 753 * SRC ports. 754 */ 755 if (iph->saddr != x->props.saddr.a4 || 756 source != encap->encap_sport) { 757 xfrm_address_t ipaddr; 758 759 ipaddr.a4 = iph->saddr; 760 km_new_mapping(x, &ipaddr, source); 761 762 /* XXX: perhaps add an extra 763 * policy check here, to see 764 * if we should allow or 765 * reject a packet from a 766 * different source 767 * address/port. 768 */ 769 } 770 771 /* 772 * 2) ignore UDP/TCP checksums in case 773 * of NAT-T in Transport Mode, or 774 * perform other post-processing fixes 775 * as per draft-ietf-ipsec-udp-encaps-06, 776 * section 3.1.2 777 */ 778 if (x->props.mode == XFRM_MODE_TRANSPORT) 779 skb->ip_summed = CHECKSUM_UNNECESSARY; 780 } 781 782 skb_pull_rcsum(skb, hlen); 783 if (x->props.mode == XFRM_MODE_TUNNEL || 784 x->props.mode == XFRM_MODE_IPTFS) 785 skb_reset_transport_header(skb); 786 else 787 skb_set_transport_header(skb, -ihl); 788 789 /* RFC4303: Drop dummy packets without any error */ 790 if (err == IPPROTO_NONE) 791 err = -EINVAL; 792 793 out: 794 return err; 795 } 796 EXPORT_SYMBOL_GPL(esp_input_done2); 797 798 static void esp_input_done(void *data, int err) 799 { 800 struct sk_buff *skb = data; 801 802 xfrm_input_resume(skb, esp_input_done2(skb, err)); 803 } 804 805 static void esp_input_restore_header(struct sk_buff *skb) 806 { 807 esp_restore_header(skb, 0); 808 __skb_pull(skb, 4); 809 } 810 811 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 812 { 813 struct xfrm_state *x = xfrm_input_state(skb); 814 struct ip_esp_hdr *esph; 815 816 /* For ESN we move the header forward by 4 bytes to 817 * accommodate the high bits. We will move it back after 818 * decryption. 819 */ 820 if ((x->props.flags & XFRM_STATE_ESN)) { 821 esph = skb_push(skb, 4); 822 *seqhi = esph->spi; 823 esph->spi = esph->seq_no; 824 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 825 } 826 } 827 828 static void esp_input_done_esn(void *data, int err) 829 { 830 struct sk_buff *skb = data; 831 832 esp_input_restore_header(skb); 833 esp_input_done(data, err); 834 } 835 836 /* 837 * Note: detecting truncated vs. non-truncated authentication data is very 838 * expensive, so we only support truncated data, which is the recommended 839 * and common case. 840 */ 841 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 842 { 843 struct crypto_aead *aead = x->data; 844 struct aead_request *req; 845 struct sk_buff *trailer; 846 int ivlen = crypto_aead_ivsize(aead); 847 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 848 int nfrags; 849 int assoclen; 850 int seqhilen; 851 __be32 *seqhi; 852 void *tmp; 853 u8 *iv; 854 struct scatterlist *sg; 855 int err = -EINVAL; 856 857 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) 858 goto out; 859 860 if (elen <= 0) 861 goto out; 862 863 assoclen = sizeof(struct ip_esp_hdr); 864 seqhilen = 0; 865 866 if (x->props.flags & XFRM_STATE_ESN) { 867 seqhilen += sizeof(__be32); 868 assoclen += seqhilen; 869 } 870 871 if (!skb_cloned(skb)) { 872 if (!skb_is_nonlinear(skb)) { 873 nfrags = 1; 874 875 goto skip_cow; 876 } else if (!skb_has_frag_list(skb)) { 877 nfrags = skb_shinfo(skb)->nr_frags; 878 nfrags++; 879 880 goto skip_cow; 881 } 882 } 883 884 err = skb_cow_data(skb, 0, &trailer); 885 if (err < 0) 886 goto out; 887 888 nfrags = err; 889 890 skip_cow: 891 err = -ENOMEM; 892 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 893 if (!tmp) 894 goto out; 895 896 ESP_SKB_CB(skb)->tmp = tmp; 897 seqhi = esp_tmp_extra(tmp); 898 iv = esp_tmp_iv(aead, tmp, seqhilen); 899 req = esp_tmp_req(aead, iv); 900 sg = esp_req_sg(aead, req); 901 902 esp_input_set_header(skb, seqhi); 903 904 sg_init_table(sg, nfrags); 905 err = skb_to_sgvec(skb, sg, 0, skb->len); 906 if (unlikely(err < 0)) { 907 kfree(tmp); 908 goto out; 909 } 910 911 skb->ip_summed = CHECKSUM_NONE; 912 913 if ((x->props.flags & XFRM_STATE_ESN)) 914 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 915 else 916 aead_request_set_callback(req, 0, esp_input_done, skb); 917 918 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 919 aead_request_set_ad(req, assoclen); 920 921 err = crypto_aead_decrypt(req); 922 if (err == -EINPROGRESS) 923 goto out; 924 925 if ((x->props.flags & XFRM_STATE_ESN)) 926 esp_input_restore_header(skb); 927 928 err = esp_input_done2(skb, err); 929 930 out: 931 return err; 932 } 933 934 static int esp4_err(struct sk_buff *skb, u32 info) 935 { 936 struct net *net = dev_net(skb->dev); 937 const struct iphdr *iph = (const struct iphdr *)skb->data; 938 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 939 struct xfrm_state *x; 940 941 switch (icmp_hdr(skb)->type) { 942 case ICMP_DEST_UNREACH: 943 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 944 return 0; 945 break; 946 case ICMP_REDIRECT: 947 break; 948 default: 949 return 0; 950 } 951 952 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 953 esph->spi, IPPROTO_ESP, AF_INET); 954 if (!x) 955 return 0; 956 957 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 958 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP); 959 else 960 ipv4_redirect(skb, net, 0, IPPROTO_ESP); 961 xfrm_state_put(x); 962 963 return 0; 964 } 965 966 static void esp_destroy(struct xfrm_state *x) 967 { 968 struct crypto_aead *aead = x->data; 969 970 if (!aead) 971 return; 972 973 crypto_free_aead(aead); 974 } 975 976 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 977 { 978 char aead_name[CRYPTO_MAX_ALG_NAME]; 979 struct crypto_aead *aead; 980 int err; 981 982 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 983 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 984 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 985 return -ENAMETOOLONG; 986 } 987 988 aead = crypto_alloc_aead(aead_name, 0, 0); 989 err = PTR_ERR(aead); 990 if (IS_ERR(aead)) 991 goto error; 992 993 x->data = aead; 994 995 err = crypto_aead_setkey(aead, x->aead->alg_key, 996 (x->aead->alg_key_len + 7) / 8); 997 if (err) 998 goto error; 999 1000 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1001 if (err) 1002 goto error; 1003 1004 return 0; 1005 1006 error: 1007 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1008 return err; 1009 } 1010 1011 static int esp_init_authenc(struct xfrm_state *x, 1012 struct netlink_ext_ack *extack) 1013 { 1014 struct crypto_aead *aead; 1015 struct crypto_authenc_key_param *param; 1016 struct rtattr *rta; 1017 char *key; 1018 char *p; 1019 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1020 unsigned int keylen; 1021 int err; 1022 1023 err = -ENAMETOOLONG; 1024 1025 if ((x->props.flags & XFRM_STATE_ESN)) { 1026 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1027 "%s%sauthencesn(%s,%s)%s", 1028 x->geniv ?: "", x->geniv ? "(" : "", 1029 x->aalg ? x->aalg->alg_name : "digest_null", 1030 x->ealg->alg_name, 1031 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1032 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1033 goto error; 1034 } 1035 } else { 1036 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1037 "%s%sauthenc(%s,%s)%s", 1038 x->geniv ?: "", x->geniv ? "(" : "", 1039 x->aalg ? x->aalg->alg_name : "digest_null", 1040 x->ealg->alg_name, 1041 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1042 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1043 goto error; 1044 } 1045 } 1046 1047 aead = crypto_alloc_aead(authenc_name, 0, 0); 1048 err = PTR_ERR(aead); 1049 if (IS_ERR(aead)) { 1050 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1051 goto error; 1052 } 1053 1054 x->data = aead; 1055 1056 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1057 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1058 err = -ENOMEM; 1059 key = kmalloc(keylen, GFP_KERNEL); 1060 if (!key) 1061 goto error; 1062 1063 p = key; 1064 rta = (void *)p; 1065 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1066 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1067 param = RTA_DATA(rta); 1068 p += RTA_SPACE(sizeof(*param)); 1069 1070 if (x->aalg) { 1071 struct xfrm_algo_desc *aalg_desc; 1072 1073 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1074 p += (x->aalg->alg_key_len + 7) / 8; 1075 1076 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1077 BUG_ON(!aalg_desc); 1078 1079 err = -EINVAL; 1080 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1081 crypto_aead_authsize(aead)) { 1082 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1083 goto free_key; 1084 } 1085 1086 err = crypto_aead_setauthsize( 1087 aead, x->aalg->alg_trunc_len / 8); 1088 if (err) { 1089 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1090 goto free_key; 1091 } 1092 } 1093 1094 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1095 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1096 1097 err = crypto_aead_setkey(aead, key, keylen); 1098 1099 free_key: 1100 kfree_sensitive(key); 1101 1102 error: 1103 return err; 1104 } 1105 1106 static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1107 { 1108 struct crypto_aead *aead; 1109 u32 align; 1110 int err; 1111 1112 x->data = NULL; 1113 1114 if (x->aead) { 1115 err = esp_init_aead(x, extack); 1116 } else if (x->ealg) { 1117 err = esp_init_authenc(x, extack); 1118 } else { 1119 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1120 err = -EINVAL; 1121 } 1122 1123 if (err) 1124 goto error; 1125 1126 aead = x->data; 1127 1128 x->props.header_len = sizeof(struct ip_esp_hdr) + 1129 crypto_aead_ivsize(aead); 1130 if (x->props.mode == XFRM_MODE_TUNNEL) 1131 x->props.header_len += sizeof(struct iphdr); 1132 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 1133 x->props.header_len += IPV4_BEET_PHMAXLEN; 1134 if (x->encap) { 1135 struct xfrm_encap_tmpl *encap = x->encap; 1136 1137 switch (encap->encap_type) { 1138 default: 1139 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1140 err = -EINVAL; 1141 goto error; 1142 case UDP_ENCAP_ESPINUDP: 1143 x->props.header_len += sizeof(struct udphdr); 1144 break; 1145 #ifdef CONFIG_INET_ESPINTCP 1146 case TCP_ENCAP_ESPINTCP: 1147 /* only the length field, TCP encap is done by 1148 * the socket 1149 */ 1150 x->props.header_len += 2; 1151 break; 1152 #endif 1153 } 1154 } 1155 1156 align = ALIGN(crypto_aead_blocksize(aead), 4); 1157 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1158 1159 error: 1160 return err; 1161 } 1162 1163 static int esp4_rcv_cb(struct sk_buff *skb, int err) 1164 { 1165 return 0; 1166 } 1167 1168 static const struct xfrm_type esp_type = 1169 { 1170 .owner = THIS_MODULE, 1171 .proto = IPPROTO_ESP, 1172 .flags = XFRM_TYPE_REPLAY_PROT, 1173 .init_state = esp_init_state, 1174 .destructor = esp_destroy, 1175 .input = esp_input, 1176 .output = esp_output, 1177 }; 1178 1179 static struct xfrm4_protocol esp4_protocol = { 1180 .handler = xfrm4_rcv, 1181 .input_handler = xfrm_input, 1182 .cb_handler = esp4_rcv_cb, 1183 .err_handler = esp4_err, 1184 .priority = 0, 1185 }; 1186 1187 static int __init esp4_init(void) 1188 { 1189 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 1190 pr_info("%s: can't add xfrm type\n", __func__); 1191 return -EAGAIN; 1192 } 1193 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 1194 pr_info("%s: can't add protocol\n", __func__); 1195 xfrm_unregister_type(&esp_type, AF_INET); 1196 return -EAGAIN; 1197 } 1198 return 0; 1199 } 1200 1201 static void __exit esp4_fini(void) 1202 { 1203 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 1204 pr_info("%s: can't remove protocol\n", __func__); 1205 xfrm_unregister_type(&esp_type, AF_INET); 1206 } 1207 1208 module_init(esp4_init); 1209 module_exit(esp4_fini); 1210 MODULE_DESCRIPTION("IPv4 ESP transformation library"); 1211 MODULE_LICENSE("GPL"); 1212 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1213