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 24 #include <linux/highmem.h> 25 26 struct esp_skb_cb { 27 struct xfrm_skb_cb xfrm; 28 void *tmp; 29 }; 30 31 struct esp_output_extra { 32 __be32 seqhi; 33 u32 esphoff; 34 }; 35 36 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0])) 37 38 /* 39 * Allocate an AEAD request structure with extra space for SG and IV. 40 * 41 * For alignment considerations the IV is placed at the front, followed 42 * by the request and finally the SG list. 43 * 44 * TODO: Use spare space in skb for this where possible. 45 */ 46 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen) 47 { 48 unsigned int len; 49 50 len = extralen; 51 52 len += crypto_aead_ivsize(aead); 53 54 if (len) { 55 len += crypto_aead_alignmask(aead) & 56 ~(crypto_tfm_ctx_alignment() - 1); 57 len = ALIGN(len, crypto_tfm_ctx_alignment()); 58 } 59 60 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead); 61 len = ALIGN(len, __alignof__(struct scatterlist)); 62 63 len += sizeof(struct scatterlist) * nfrags; 64 65 return kmalloc(len, GFP_ATOMIC); 66 } 67 68 static inline void *esp_tmp_extra(void *tmp) 69 { 70 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra)); 71 } 72 73 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen) 74 { 75 return crypto_aead_ivsize(aead) ? 76 PTR_ALIGN((u8 *)tmp + extralen, 77 crypto_aead_alignmask(aead) + 1) : tmp + extralen; 78 } 79 80 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv) 81 { 82 struct aead_request *req; 83 84 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead), 85 crypto_tfm_ctx_alignment()); 86 aead_request_set_tfm(req, aead); 87 return req; 88 } 89 90 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead, 91 struct aead_request *req) 92 { 93 return (void *)ALIGN((unsigned long)(req + 1) + 94 crypto_aead_reqsize(aead), 95 __alignof__(struct scatterlist)); 96 } 97 98 static void esp_ssg_unref(struct xfrm_state *x, void *tmp) 99 { 100 struct crypto_aead *aead = x->data; 101 int extralen = 0; 102 u8 *iv; 103 struct aead_request *req; 104 struct scatterlist *sg; 105 106 if (x->props.flags & XFRM_STATE_ESN) 107 extralen += sizeof(struct esp_output_extra); 108 109 iv = esp_tmp_iv(aead, tmp, extralen); 110 req = esp_tmp_req(aead, iv); 111 112 /* Unref skb_frag_pages in the src scatterlist if necessary. 113 * Skip the first sg which comes from skb->data. 114 */ 115 if (req->src != req->dst) 116 for (sg = sg_next(req->src); sg; sg = sg_next(sg)) 117 put_page(sg_page(sg)); 118 } 119 120 #ifdef CONFIG_INET_ESPINTCP 121 struct esp_tcp_sk { 122 struct sock *sk; 123 struct rcu_head rcu; 124 }; 125 126 static void esp_free_tcp_sk(struct rcu_head *head) 127 { 128 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu); 129 130 sock_put(esk->sk); 131 kfree(esk); 132 } 133 134 static struct sock *esp_find_tcp_sk(struct xfrm_state *x) 135 { 136 struct xfrm_encap_tmpl *encap = x->encap; 137 struct esp_tcp_sk *esk; 138 __be16 sport, dport; 139 struct sock *nsk; 140 struct sock *sk; 141 142 sk = rcu_dereference(x->encap_sk); 143 if (sk && sk->sk_state == TCP_ESTABLISHED) 144 return sk; 145 146 spin_lock_bh(&x->lock); 147 sport = encap->encap_sport; 148 dport = encap->encap_dport; 149 nsk = rcu_dereference_protected(x->encap_sk, 150 lockdep_is_held(&x->lock)); 151 if (sk && sk == nsk) { 152 esk = kmalloc(sizeof(*esk), GFP_ATOMIC); 153 if (!esk) { 154 spin_unlock_bh(&x->lock); 155 return ERR_PTR(-ENOMEM); 156 } 157 RCU_INIT_POINTER(x->encap_sk, NULL); 158 esk->sk = sk; 159 call_rcu(&esk->rcu, esp_free_tcp_sk); 160 } 161 spin_unlock_bh(&x->lock); 162 163 sk = inet_lookup_established(xs_net(x), &tcp_hashinfo, x->id.daddr.a4, 164 dport, x->props.saddr.a4, sport, 0); 165 if (!sk) 166 return ERR_PTR(-ENOENT); 167 168 if (!tcp_is_ulp_esp(sk)) { 169 sock_put(sk); 170 return ERR_PTR(-EINVAL); 171 } 172 173 spin_lock_bh(&x->lock); 174 nsk = rcu_dereference_protected(x->encap_sk, 175 lockdep_is_held(&x->lock)); 176 if (encap->encap_sport != sport || 177 encap->encap_dport != dport) { 178 sock_put(sk); 179 sk = nsk ?: ERR_PTR(-EREMCHG); 180 } else if (sk == nsk) { 181 sock_put(sk); 182 } else { 183 rcu_assign_pointer(x->encap_sk, sk); 184 } 185 spin_unlock_bh(&x->lock); 186 187 return sk; 188 } 189 190 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) 191 { 192 struct sock *sk; 193 int err; 194 195 rcu_read_lock(); 196 197 sk = esp_find_tcp_sk(x); 198 err = PTR_ERR_OR_ZERO(sk); 199 if (err) 200 goto out; 201 202 bh_lock_sock(sk); 203 if (sock_owned_by_user(sk)) 204 err = espintcp_queue_out(sk, skb); 205 else 206 err = espintcp_push_skb(sk, skb); 207 bh_unlock_sock(sk); 208 209 out: 210 rcu_read_unlock(); 211 return err; 212 } 213 214 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk, 215 struct sk_buff *skb) 216 { 217 struct dst_entry *dst = skb_dst(skb); 218 struct xfrm_state *x = dst->xfrm; 219 220 return esp_output_tcp_finish(x, skb); 221 } 222 223 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 224 { 225 int err; 226 227 local_bh_disable(); 228 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb); 229 local_bh_enable(); 230 231 /* EINPROGRESS just happens to do the right thing. It 232 * actually means that the skb has been consumed and 233 * isn't coming back. 234 */ 235 return err ?: -EINPROGRESS; 236 } 237 #else 238 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 239 { 240 kfree_skb(skb); 241 242 return -EOPNOTSUPP; 243 } 244 #endif 245 246 static void esp_output_done(struct crypto_async_request *base, int err) 247 { 248 struct sk_buff *skb = base->data; 249 struct xfrm_offload *xo = xfrm_offload(skb); 250 void *tmp; 251 struct xfrm_state *x; 252 253 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 254 struct sec_path *sp = skb_sec_path(skb); 255 256 x = sp->xvec[sp->len - 1]; 257 } else { 258 x = skb_dst(skb)->xfrm; 259 } 260 261 tmp = ESP_SKB_CB(skb)->tmp; 262 esp_ssg_unref(x, tmp); 263 kfree(tmp); 264 265 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 266 if (err) { 267 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR); 268 kfree_skb(skb); 269 return; 270 } 271 272 skb_push(skb, skb->data - skb_mac_header(skb)); 273 secpath_reset(skb); 274 xfrm_dev_resume(skb); 275 } else { 276 if (!err && 277 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 278 esp_output_tail_tcp(x, skb); 279 else 280 xfrm_output_resume(skb->sk, skb, err); 281 } 282 } 283 284 /* Move ESP header back into place. */ 285 static void esp_restore_header(struct sk_buff *skb, unsigned int offset) 286 { 287 struct ip_esp_hdr *esph = (void *)(skb->data + offset); 288 void *tmp = ESP_SKB_CB(skb)->tmp; 289 __be32 *seqhi = esp_tmp_extra(tmp); 290 291 esph->seq_no = esph->spi; 292 esph->spi = *seqhi; 293 } 294 295 static void esp_output_restore_header(struct sk_buff *skb) 296 { 297 void *tmp = ESP_SKB_CB(skb)->tmp; 298 struct esp_output_extra *extra = esp_tmp_extra(tmp); 299 300 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff - 301 sizeof(__be32)); 302 } 303 304 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb, 305 struct xfrm_state *x, 306 struct ip_esp_hdr *esph, 307 struct esp_output_extra *extra) 308 { 309 /* For ESN we move the header forward by 4 bytes to 310 * accommodate the high bits. We will move it back after 311 * encryption. 312 */ 313 if ((x->props.flags & XFRM_STATE_ESN)) { 314 __u32 seqhi; 315 struct xfrm_offload *xo = xfrm_offload(skb); 316 317 if (xo) 318 seqhi = xo->seq.hi; 319 else 320 seqhi = XFRM_SKB_CB(skb)->seq.output.hi; 321 322 extra->esphoff = (unsigned char *)esph - 323 skb_transport_header(skb); 324 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4); 325 extra->seqhi = esph->spi; 326 esph->seq_no = htonl(seqhi); 327 } 328 329 esph->spi = x->id.spi; 330 331 return esph; 332 } 333 334 static void esp_output_done_esn(struct crypto_async_request *base, int err) 335 { 336 struct sk_buff *skb = base->data; 337 338 esp_output_restore_header(skb); 339 esp_output_done(base, err); 340 } 341 342 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb, 343 int encap_type, 344 struct esp_info *esp, 345 __be16 sport, 346 __be16 dport) 347 { 348 struct udphdr *uh; 349 __be32 *udpdata32; 350 unsigned int len; 351 352 len = skb->len + esp->tailen - skb_transport_offset(skb); 353 if (len + sizeof(struct iphdr) > IP_MAX_MTU) 354 return ERR_PTR(-EMSGSIZE); 355 356 uh = (struct udphdr *)esp->esph; 357 uh->source = sport; 358 uh->dest = dport; 359 uh->len = htons(len); 360 uh->check = 0; 361 362 *skb_mac_header(skb) = IPPROTO_UDP; 363 364 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) { 365 udpdata32 = (__be32 *)(uh + 1); 366 udpdata32[0] = udpdata32[1] = 0; 367 return (struct ip_esp_hdr *)(udpdata32 + 2); 368 } 369 370 return (struct ip_esp_hdr *)(uh + 1); 371 } 372 373 #ifdef CONFIG_INET_ESPINTCP 374 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 375 struct sk_buff *skb, 376 struct esp_info *esp) 377 { 378 __be16 *lenp = (void *)esp->esph; 379 struct ip_esp_hdr *esph; 380 unsigned int len; 381 struct sock *sk; 382 383 len = skb->len + esp->tailen - skb_transport_offset(skb); 384 if (len > IP_MAX_MTU) 385 return ERR_PTR(-EMSGSIZE); 386 387 rcu_read_lock(); 388 sk = esp_find_tcp_sk(x); 389 rcu_read_unlock(); 390 391 if (IS_ERR(sk)) 392 return ERR_CAST(sk); 393 394 *lenp = htons(len); 395 esph = (struct ip_esp_hdr *)(lenp + 1); 396 397 return esph; 398 } 399 #else 400 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 401 struct sk_buff *skb, 402 struct esp_info *esp) 403 { 404 return ERR_PTR(-EOPNOTSUPP); 405 } 406 #endif 407 408 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb, 409 struct esp_info *esp) 410 { 411 struct xfrm_encap_tmpl *encap = x->encap; 412 struct ip_esp_hdr *esph; 413 __be16 sport, dport; 414 int encap_type; 415 416 spin_lock_bh(&x->lock); 417 sport = encap->encap_sport; 418 dport = encap->encap_dport; 419 encap_type = encap->encap_type; 420 spin_unlock_bh(&x->lock); 421 422 switch (encap_type) { 423 default: 424 case UDP_ENCAP_ESPINUDP: 425 case UDP_ENCAP_ESPINUDP_NON_IKE: 426 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport); 427 break; 428 case TCP_ENCAP_ESPINTCP: 429 esph = esp_output_tcp_encap(x, skb, esp); 430 break; 431 } 432 433 if (IS_ERR(esph)) 434 return PTR_ERR(esph); 435 436 esp->esph = esph; 437 438 return 0; 439 } 440 441 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 442 { 443 u8 *tail; 444 int nfrags; 445 int esph_offset; 446 struct page *page; 447 struct sk_buff *trailer; 448 int tailen = esp->tailen; 449 450 /* this is non-NULL only with TCP/UDP Encapsulation */ 451 if (x->encap) { 452 int err = esp_output_encap(x, skb, esp); 453 454 if (err < 0) 455 return err; 456 } 457 458 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE || 459 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE) 460 goto cow; 461 462 if (!skb_cloned(skb)) { 463 if (tailen <= skb_tailroom(skb)) { 464 nfrags = 1; 465 trailer = skb; 466 tail = skb_tail_pointer(trailer); 467 468 goto skip_cow; 469 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 470 && !skb_has_frag_list(skb)) { 471 int allocsize; 472 struct sock *sk = skb->sk; 473 struct page_frag *pfrag = &x->xfrag; 474 475 esp->inplace = false; 476 477 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 478 479 spin_lock_bh(&x->lock); 480 481 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 482 spin_unlock_bh(&x->lock); 483 goto cow; 484 } 485 486 page = pfrag->page; 487 get_page(page); 488 489 tail = page_address(page) + pfrag->offset; 490 491 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 492 493 nfrags = skb_shinfo(skb)->nr_frags; 494 495 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 496 tailen); 497 skb_shinfo(skb)->nr_frags = ++nfrags; 498 499 pfrag->offset = pfrag->offset + allocsize; 500 501 spin_unlock_bh(&x->lock); 502 503 nfrags++; 504 505 skb_len_add(skb, tailen); 506 if (sk && sk_fullsock(sk)) 507 refcount_add(tailen, &sk->sk_wmem_alloc); 508 509 goto out; 510 } 511 } 512 513 cow: 514 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 515 516 nfrags = skb_cow_data(skb, tailen, &trailer); 517 if (nfrags < 0) 518 goto out; 519 tail = skb_tail_pointer(trailer); 520 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 521 522 skip_cow: 523 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 524 pskb_put(skb, trailer, tailen); 525 526 out: 527 return nfrags; 528 } 529 EXPORT_SYMBOL_GPL(esp_output_head); 530 531 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 532 { 533 u8 *iv; 534 int alen; 535 void *tmp; 536 int ivlen; 537 int assoclen; 538 int extralen; 539 struct page *page; 540 struct ip_esp_hdr *esph; 541 struct crypto_aead *aead; 542 struct aead_request *req; 543 struct scatterlist *sg, *dsg; 544 struct esp_output_extra *extra; 545 int err = -ENOMEM; 546 547 assoclen = sizeof(struct ip_esp_hdr); 548 extralen = 0; 549 550 if (x->props.flags & XFRM_STATE_ESN) { 551 extralen += sizeof(*extra); 552 assoclen += sizeof(__be32); 553 } 554 555 aead = x->data; 556 alen = crypto_aead_authsize(aead); 557 ivlen = crypto_aead_ivsize(aead); 558 559 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 560 if (!tmp) 561 goto error; 562 563 extra = esp_tmp_extra(tmp); 564 iv = esp_tmp_iv(aead, tmp, extralen); 565 req = esp_tmp_req(aead, iv); 566 sg = esp_req_sg(aead, req); 567 568 if (esp->inplace) 569 dsg = sg; 570 else 571 dsg = &sg[esp->nfrags]; 572 573 esph = esp_output_set_extra(skb, x, esp->esph, extra); 574 esp->esph = esph; 575 576 sg_init_table(sg, esp->nfrags); 577 err = skb_to_sgvec(skb, sg, 578 (unsigned char *)esph - skb->data, 579 assoclen + ivlen + esp->clen + alen); 580 if (unlikely(err < 0)) 581 goto error_free; 582 583 if (!esp->inplace) { 584 int allocsize; 585 struct page_frag *pfrag = &x->xfrag; 586 587 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 588 589 spin_lock_bh(&x->lock); 590 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 591 spin_unlock_bh(&x->lock); 592 goto error_free; 593 } 594 595 skb_shinfo(skb)->nr_frags = 1; 596 597 page = pfrag->page; 598 get_page(page); 599 /* replace page frags in skb with new page */ 600 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 601 pfrag->offset = pfrag->offset + allocsize; 602 spin_unlock_bh(&x->lock); 603 604 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 605 err = skb_to_sgvec(skb, dsg, 606 (unsigned char *)esph - skb->data, 607 assoclen + ivlen + esp->clen + alen); 608 if (unlikely(err < 0)) 609 goto error_free; 610 } 611 612 if ((x->props.flags & XFRM_STATE_ESN)) 613 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 614 else 615 aead_request_set_callback(req, 0, esp_output_done, skb); 616 617 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 618 aead_request_set_ad(req, assoclen); 619 620 memset(iv, 0, ivlen); 621 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 622 min(ivlen, 8)); 623 624 ESP_SKB_CB(skb)->tmp = tmp; 625 err = crypto_aead_encrypt(req); 626 627 switch (err) { 628 case -EINPROGRESS: 629 goto error; 630 631 case -ENOSPC: 632 err = NET_XMIT_DROP; 633 break; 634 635 case 0: 636 if ((x->props.flags & XFRM_STATE_ESN)) 637 esp_output_restore_header(skb); 638 } 639 640 if (sg != dsg) 641 esp_ssg_unref(x, tmp); 642 643 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 644 err = esp_output_tail_tcp(x, skb); 645 646 error_free: 647 kfree(tmp); 648 error: 649 return err; 650 } 651 EXPORT_SYMBOL_GPL(esp_output_tail); 652 653 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 654 { 655 int alen; 656 int blksize; 657 struct ip_esp_hdr *esph; 658 struct crypto_aead *aead; 659 struct esp_info esp; 660 661 esp.inplace = true; 662 663 esp.proto = *skb_mac_header(skb); 664 *skb_mac_header(skb) = IPPROTO_ESP; 665 666 /* skb is pure payload to encrypt */ 667 668 aead = x->data; 669 alen = crypto_aead_authsize(aead); 670 671 esp.tfclen = 0; 672 if (x->tfcpad) { 673 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 674 u32 padto; 675 676 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 677 if (skb->len < padto) 678 esp.tfclen = padto - skb->len; 679 } 680 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 681 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 682 esp.plen = esp.clen - skb->len - esp.tfclen; 683 esp.tailen = esp.tfclen + esp.plen + alen; 684 685 esp.esph = ip_esp_hdr(skb); 686 687 esp.nfrags = esp_output_head(x, skb, &esp); 688 if (esp.nfrags < 0) 689 return esp.nfrags; 690 691 esph = esp.esph; 692 esph->spi = x->id.spi; 693 694 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 695 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 696 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 697 698 skb_push(skb, -skb_network_offset(skb)); 699 700 return esp_output_tail(x, skb, &esp); 701 } 702 703 static inline int esp_remove_trailer(struct sk_buff *skb) 704 { 705 struct xfrm_state *x = xfrm_input_state(skb); 706 struct crypto_aead *aead = x->data; 707 int alen, hlen, elen; 708 int padlen, trimlen; 709 __wsum csumdiff; 710 u8 nexthdr[2]; 711 int ret; 712 713 alen = crypto_aead_authsize(aead); 714 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 715 elen = skb->len - hlen; 716 717 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) 718 BUG(); 719 720 ret = -EINVAL; 721 padlen = nexthdr[0]; 722 if (padlen + 2 + alen >= elen) { 723 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 724 padlen + 2, elen - alen); 725 goto out; 726 } 727 728 trimlen = alen + padlen + 2; 729 if (skb->ip_summed == CHECKSUM_COMPLETE) { 730 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 731 skb->csum = csum_block_sub(skb->csum, csumdiff, 732 skb->len - trimlen); 733 } 734 pskb_trim(skb, skb->len - trimlen); 735 736 ret = nexthdr[1]; 737 738 out: 739 return ret; 740 } 741 742 int esp_input_done2(struct sk_buff *skb, int err) 743 { 744 const struct iphdr *iph; 745 struct xfrm_state *x = xfrm_input_state(skb); 746 struct xfrm_offload *xo = xfrm_offload(skb); 747 struct crypto_aead *aead = x->data; 748 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 749 int ihl; 750 751 if (!xo || !(xo->flags & CRYPTO_DONE)) 752 kfree(ESP_SKB_CB(skb)->tmp); 753 754 if (unlikely(err)) 755 goto out; 756 757 err = esp_remove_trailer(skb); 758 if (unlikely(err < 0)) 759 goto out; 760 761 iph = ip_hdr(skb); 762 ihl = iph->ihl * 4; 763 764 if (x->encap) { 765 struct xfrm_encap_tmpl *encap = x->encap; 766 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl); 767 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 768 __be16 source; 769 770 switch (x->encap->encap_type) { 771 case TCP_ENCAP_ESPINTCP: 772 source = th->source; 773 break; 774 case UDP_ENCAP_ESPINUDP: 775 case UDP_ENCAP_ESPINUDP_NON_IKE: 776 source = uh->source; 777 break; 778 default: 779 WARN_ON_ONCE(1); 780 err = -EINVAL; 781 goto out; 782 } 783 784 /* 785 * 1) if the NAT-T peer's IP or port changed then 786 * advertize the change to the keying daemon. 787 * This is an inbound SA, so just compare 788 * SRC ports. 789 */ 790 if (iph->saddr != x->props.saddr.a4 || 791 source != encap->encap_sport) { 792 xfrm_address_t ipaddr; 793 794 ipaddr.a4 = iph->saddr; 795 km_new_mapping(x, &ipaddr, source); 796 797 /* XXX: perhaps add an extra 798 * policy check here, to see 799 * if we should allow or 800 * reject a packet from a 801 * different source 802 * address/port. 803 */ 804 } 805 806 /* 807 * 2) ignore UDP/TCP checksums in case 808 * of NAT-T in Transport Mode, or 809 * perform other post-processing fixes 810 * as per draft-ietf-ipsec-udp-encaps-06, 811 * section 3.1.2 812 */ 813 if (x->props.mode == XFRM_MODE_TRANSPORT) 814 skb->ip_summed = CHECKSUM_UNNECESSARY; 815 } 816 817 skb_pull_rcsum(skb, hlen); 818 if (x->props.mode == XFRM_MODE_TUNNEL) 819 skb_reset_transport_header(skb); 820 else 821 skb_set_transport_header(skb, -ihl); 822 823 /* RFC4303: Drop dummy packets without any error */ 824 if (err == IPPROTO_NONE) 825 err = -EINVAL; 826 827 out: 828 return err; 829 } 830 EXPORT_SYMBOL_GPL(esp_input_done2); 831 832 static void esp_input_done(struct crypto_async_request *base, int err) 833 { 834 struct sk_buff *skb = base->data; 835 836 xfrm_input_resume(skb, esp_input_done2(skb, err)); 837 } 838 839 static void esp_input_restore_header(struct sk_buff *skb) 840 { 841 esp_restore_header(skb, 0); 842 __skb_pull(skb, 4); 843 } 844 845 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 846 { 847 struct xfrm_state *x = xfrm_input_state(skb); 848 struct ip_esp_hdr *esph; 849 850 /* For ESN we move the header forward by 4 bytes to 851 * accommodate the high bits. We will move it back after 852 * decryption. 853 */ 854 if ((x->props.flags & XFRM_STATE_ESN)) { 855 esph = skb_push(skb, 4); 856 *seqhi = esph->spi; 857 esph->spi = esph->seq_no; 858 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 859 } 860 } 861 862 static void esp_input_done_esn(struct crypto_async_request *base, int err) 863 { 864 struct sk_buff *skb = base->data; 865 866 esp_input_restore_header(skb); 867 esp_input_done(base, err); 868 } 869 870 /* 871 * Note: detecting truncated vs. non-truncated authentication data is very 872 * expensive, so we only support truncated data, which is the recommended 873 * and common case. 874 */ 875 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 876 { 877 struct crypto_aead *aead = x->data; 878 struct aead_request *req; 879 struct sk_buff *trailer; 880 int ivlen = crypto_aead_ivsize(aead); 881 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 882 int nfrags; 883 int assoclen; 884 int seqhilen; 885 __be32 *seqhi; 886 void *tmp; 887 u8 *iv; 888 struct scatterlist *sg; 889 int err = -EINVAL; 890 891 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) 892 goto out; 893 894 if (elen <= 0) 895 goto out; 896 897 assoclen = sizeof(struct ip_esp_hdr); 898 seqhilen = 0; 899 900 if (x->props.flags & XFRM_STATE_ESN) { 901 seqhilen += sizeof(__be32); 902 assoclen += seqhilen; 903 } 904 905 if (!skb_cloned(skb)) { 906 if (!skb_is_nonlinear(skb)) { 907 nfrags = 1; 908 909 goto skip_cow; 910 } else if (!skb_has_frag_list(skb)) { 911 nfrags = skb_shinfo(skb)->nr_frags; 912 nfrags++; 913 914 goto skip_cow; 915 } 916 } 917 918 err = skb_cow_data(skb, 0, &trailer); 919 if (err < 0) 920 goto out; 921 922 nfrags = err; 923 924 skip_cow: 925 err = -ENOMEM; 926 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 927 if (!tmp) 928 goto out; 929 930 ESP_SKB_CB(skb)->tmp = tmp; 931 seqhi = esp_tmp_extra(tmp); 932 iv = esp_tmp_iv(aead, tmp, seqhilen); 933 req = esp_tmp_req(aead, iv); 934 sg = esp_req_sg(aead, req); 935 936 esp_input_set_header(skb, seqhi); 937 938 sg_init_table(sg, nfrags); 939 err = skb_to_sgvec(skb, sg, 0, skb->len); 940 if (unlikely(err < 0)) { 941 kfree(tmp); 942 goto out; 943 } 944 945 skb->ip_summed = CHECKSUM_NONE; 946 947 if ((x->props.flags & XFRM_STATE_ESN)) 948 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 949 else 950 aead_request_set_callback(req, 0, esp_input_done, skb); 951 952 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 953 aead_request_set_ad(req, assoclen); 954 955 err = crypto_aead_decrypt(req); 956 if (err == -EINPROGRESS) 957 goto out; 958 959 if ((x->props.flags & XFRM_STATE_ESN)) 960 esp_input_restore_header(skb); 961 962 err = esp_input_done2(skb, err); 963 964 out: 965 return err; 966 } 967 968 static int esp4_err(struct sk_buff *skb, u32 info) 969 { 970 struct net *net = dev_net(skb->dev); 971 const struct iphdr *iph = (const struct iphdr *)skb->data; 972 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 973 struct xfrm_state *x; 974 975 switch (icmp_hdr(skb)->type) { 976 case ICMP_DEST_UNREACH: 977 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 978 return 0; 979 break; 980 case ICMP_REDIRECT: 981 break; 982 default: 983 return 0; 984 } 985 986 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 987 esph->spi, IPPROTO_ESP, AF_INET); 988 if (!x) 989 return 0; 990 991 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 992 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP); 993 else 994 ipv4_redirect(skb, net, 0, IPPROTO_ESP); 995 xfrm_state_put(x); 996 997 return 0; 998 } 999 1000 static void esp_destroy(struct xfrm_state *x) 1001 { 1002 struct crypto_aead *aead = x->data; 1003 1004 if (!aead) 1005 return; 1006 1007 crypto_free_aead(aead); 1008 } 1009 1010 static int esp_init_aead(struct xfrm_state *x) 1011 { 1012 char aead_name[CRYPTO_MAX_ALG_NAME]; 1013 struct crypto_aead *aead; 1014 int err; 1015 1016 err = -ENAMETOOLONG; 1017 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1018 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) 1019 goto error; 1020 1021 aead = crypto_alloc_aead(aead_name, 0, 0); 1022 err = PTR_ERR(aead); 1023 if (IS_ERR(aead)) 1024 goto error; 1025 1026 x->data = aead; 1027 1028 err = crypto_aead_setkey(aead, x->aead->alg_key, 1029 (x->aead->alg_key_len + 7) / 8); 1030 if (err) 1031 goto error; 1032 1033 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1034 if (err) 1035 goto error; 1036 1037 error: 1038 return err; 1039 } 1040 1041 static int esp_init_authenc(struct xfrm_state *x) 1042 { 1043 struct crypto_aead *aead; 1044 struct crypto_authenc_key_param *param; 1045 struct rtattr *rta; 1046 char *key; 1047 char *p; 1048 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1049 unsigned int keylen; 1050 int err; 1051 1052 err = -EINVAL; 1053 if (!x->ealg) 1054 goto error; 1055 1056 err = -ENAMETOOLONG; 1057 1058 if ((x->props.flags & XFRM_STATE_ESN)) { 1059 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1060 "%s%sauthencesn(%s,%s)%s", 1061 x->geniv ?: "", x->geniv ? "(" : "", 1062 x->aalg ? x->aalg->alg_name : "digest_null", 1063 x->ealg->alg_name, 1064 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1065 goto error; 1066 } else { 1067 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1068 "%s%sauthenc(%s,%s)%s", 1069 x->geniv ?: "", x->geniv ? "(" : "", 1070 x->aalg ? x->aalg->alg_name : "digest_null", 1071 x->ealg->alg_name, 1072 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1073 goto error; 1074 } 1075 1076 aead = crypto_alloc_aead(authenc_name, 0, 0); 1077 err = PTR_ERR(aead); 1078 if (IS_ERR(aead)) 1079 goto error; 1080 1081 x->data = aead; 1082 1083 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1084 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1085 err = -ENOMEM; 1086 key = kmalloc(keylen, GFP_KERNEL); 1087 if (!key) 1088 goto error; 1089 1090 p = key; 1091 rta = (void *)p; 1092 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1093 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1094 param = RTA_DATA(rta); 1095 p += RTA_SPACE(sizeof(*param)); 1096 1097 if (x->aalg) { 1098 struct xfrm_algo_desc *aalg_desc; 1099 1100 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1101 p += (x->aalg->alg_key_len + 7) / 8; 1102 1103 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1104 BUG_ON(!aalg_desc); 1105 1106 err = -EINVAL; 1107 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1108 crypto_aead_authsize(aead)) { 1109 pr_info("ESP: %s digestsize %u != %u\n", 1110 x->aalg->alg_name, 1111 crypto_aead_authsize(aead), 1112 aalg_desc->uinfo.auth.icv_fullbits / 8); 1113 goto free_key; 1114 } 1115 1116 err = crypto_aead_setauthsize( 1117 aead, x->aalg->alg_trunc_len / 8); 1118 if (err) 1119 goto free_key; 1120 } 1121 1122 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1123 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1124 1125 err = crypto_aead_setkey(aead, key, keylen); 1126 1127 free_key: 1128 kfree(key); 1129 1130 error: 1131 return err; 1132 } 1133 1134 static int esp_init_state(struct xfrm_state *x) 1135 { 1136 struct crypto_aead *aead; 1137 u32 align; 1138 int err; 1139 1140 x->data = NULL; 1141 1142 if (x->aead) 1143 err = esp_init_aead(x); 1144 else 1145 err = esp_init_authenc(x); 1146 1147 if (err) 1148 goto error; 1149 1150 aead = x->data; 1151 1152 x->props.header_len = sizeof(struct ip_esp_hdr) + 1153 crypto_aead_ivsize(aead); 1154 if (x->props.mode == XFRM_MODE_TUNNEL) 1155 x->props.header_len += sizeof(struct iphdr); 1156 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 1157 x->props.header_len += IPV4_BEET_PHMAXLEN; 1158 if (x->encap) { 1159 struct xfrm_encap_tmpl *encap = x->encap; 1160 1161 switch (encap->encap_type) { 1162 default: 1163 err = -EINVAL; 1164 goto error; 1165 case UDP_ENCAP_ESPINUDP: 1166 x->props.header_len += sizeof(struct udphdr); 1167 break; 1168 case UDP_ENCAP_ESPINUDP_NON_IKE: 1169 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 1170 break; 1171 #ifdef CONFIG_INET_ESPINTCP 1172 case TCP_ENCAP_ESPINTCP: 1173 /* only the length field, TCP encap is done by 1174 * the socket 1175 */ 1176 x->props.header_len += 2; 1177 break; 1178 #endif 1179 } 1180 } 1181 1182 align = ALIGN(crypto_aead_blocksize(aead), 4); 1183 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1184 1185 error: 1186 return err; 1187 } 1188 1189 static int esp4_rcv_cb(struct sk_buff *skb, int err) 1190 { 1191 return 0; 1192 } 1193 1194 static const struct xfrm_type esp_type = 1195 { 1196 .owner = THIS_MODULE, 1197 .proto = IPPROTO_ESP, 1198 .flags = XFRM_TYPE_REPLAY_PROT, 1199 .init_state = esp_init_state, 1200 .destructor = esp_destroy, 1201 .input = esp_input, 1202 .output = esp_output, 1203 }; 1204 1205 static struct xfrm4_protocol esp4_protocol = { 1206 .handler = xfrm4_rcv, 1207 .input_handler = xfrm_input, 1208 .cb_handler = esp4_rcv_cb, 1209 .err_handler = esp4_err, 1210 .priority = 0, 1211 }; 1212 1213 static int __init esp4_init(void) 1214 { 1215 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 1216 pr_info("%s: can't add xfrm type\n", __func__); 1217 return -EAGAIN; 1218 } 1219 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 1220 pr_info("%s: can't add protocol\n", __func__); 1221 xfrm_unregister_type(&esp_type, AF_INET); 1222 return -EAGAIN; 1223 } 1224 return 0; 1225 } 1226 1227 static void __exit esp4_fini(void) 1228 { 1229 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 1230 pr_info("%s: can't remove protocol\n", __func__); 1231 xfrm_unregister_type(&esp_type, AF_INET); 1232 } 1233 1234 module_init(esp4_init); 1235 module_exit(esp4_fini); 1236 MODULE_LICENSE("GPL"); 1237 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1238