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 net *net = xs_net(x); 138 struct esp_tcp_sk *esk; 139 __be16 sport, dport; 140 struct sock *nsk; 141 struct sock *sk; 142 143 sk = rcu_dereference(x->encap_sk); 144 if (sk && sk->sk_state == TCP_ESTABLISHED) 145 return sk; 146 147 spin_lock_bh(&x->lock); 148 sport = encap->encap_sport; 149 dport = encap->encap_dport; 150 nsk = rcu_dereference_protected(x->encap_sk, 151 lockdep_is_held(&x->lock)); 152 if (sk && sk == nsk) { 153 esk = kmalloc(sizeof(*esk), GFP_ATOMIC); 154 if (!esk) { 155 spin_unlock_bh(&x->lock); 156 return ERR_PTR(-ENOMEM); 157 } 158 RCU_INIT_POINTER(x->encap_sk, NULL); 159 esk->sk = sk; 160 call_rcu(&esk->rcu, esp_free_tcp_sk); 161 } 162 spin_unlock_bh(&x->lock); 163 164 sk = inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, x->id.daddr.a4, 165 dport, x->props.saddr.a4, sport, 0); 166 if (!sk) 167 return ERR_PTR(-ENOENT); 168 169 if (!tcp_is_ulp_esp(sk)) { 170 sock_put(sk); 171 return ERR_PTR(-EINVAL); 172 } 173 174 spin_lock_bh(&x->lock); 175 nsk = rcu_dereference_protected(x->encap_sk, 176 lockdep_is_held(&x->lock)); 177 if (encap->encap_sport != sport || 178 encap->encap_dport != dport) { 179 sock_put(sk); 180 sk = nsk ?: ERR_PTR(-EREMCHG); 181 } else if (sk == nsk) { 182 sock_put(sk); 183 } else { 184 rcu_assign_pointer(x->encap_sk, sk); 185 } 186 spin_unlock_bh(&x->lock); 187 188 return sk; 189 } 190 191 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) 192 { 193 struct sock *sk; 194 int err; 195 196 rcu_read_lock(); 197 198 sk = esp_find_tcp_sk(x); 199 err = PTR_ERR_OR_ZERO(sk); 200 if (err) 201 goto out; 202 203 bh_lock_sock(sk); 204 if (sock_owned_by_user(sk)) 205 err = espintcp_queue_out(sk, skb); 206 else 207 err = espintcp_push_skb(sk, skb); 208 bh_unlock_sock(sk); 209 210 out: 211 rcu_read_unlock(); 212 return err; 213 } 214 215 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk, 216 struct sk_buff *skb) 217 { 218 struct dst_entry *dst = skb_dst(skb); 219 struct xfrm_state *x = dst->xfrm; 220 221 return esp_output_tcp_finish(x, skb); 222 } 223 224 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 225 { 226 int err; 227 228 local_bh_disable(); 229 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb); 230 local_bh_enable(); 231 232 /* EINPROGRESS just happens to do the right thing. It 233 * actually means that the skb has been consumed and 234 * isn't coming back. 235 */ 236 return err ?: -EINPROGRESS; 237 } 238 #else 239 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 240 { 241 kfree_skb(skb); 242 243 return -EOPNOTSUPP; 244 } 245 #endif 246 247 static void esp_output_done(void *data, int err) 248 { 249 struct sk_buff *skb = data; 250 struct xfrm_offload *xo = xfrm_offload(skb); 251 void *tmp; 252 struct xfrm_state *x; 253 254 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 255 struct sec_path *sp = skb_sec_path(skb); 256 257 x = sp->xvec[sp->len - 1]; 258 } else { 259 x = skb_dst(skb)->xfrm; 260 } 261 262 tmp = ESP_SKB_CB(skb)->tmp; 263 esp_ssg_unref(x, tmp); 264 kfree(tmp); 265 266 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 267 if (err) { 268 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR); 269 kfree_skb(skb); 270 return; 271 } 272 273 skb_push(skb, skb->data - skb_mac_header(skb)); 274 secpath_reset(skb); 275 xfrm_dev_resume(skb); 276 } else { 277 if (!err && 278 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 279 esp_output_tail_tcp(x, skb); 280 else 281 xfrm_output_resume(skb->sk, skb, err); 282 } 283 } 284 285 /* Move ESP header back into place. */ 286 static void esp_restore_header(struct sk_buff *skb, unsigned int offset) 287 { 288 struct ip_esp_hdr *esph = (void *)(skb->data + offset); 289 void *tmp = ESP_SKB_CB(skb)->tmp; 290 __be32 *seqhi = esp_tmp_extra(tmp); 291 292 esph->seq_no = esph->spi; 293 esph->spi = *seqhi; 294 } 295 296 static void esp_output_restore_header(struct sk_buff *skb) 297 { 298 void *tmp = ESP_SKB_CB(skb)->tmp; 299 struct esp_output_extra *extra = esp_tmp_extra(tmp); 300 301 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff - 302 sizeof(__be32)); 303 } 304 305 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb, 306 struct xfrm_state *x, 307 struct ip_esp_hdr *esph, 308 struct esp_output_extra *extra) 309 { 310 /* For ESN we move the header forward by 4 bytes to 311 * accommodate the high bits. We will move it back after 312 * encryption. 313 */ 314 if ((x->props.flags & XFRM_STATE_ESN)) { 315 __u32 seqhi; 316 struct xfrm_offload *xo = xfrm_offload(skb); 317 318 if (xo) 319 seqhi = xo->seq.hi; 320 else 321 seqhi = XFRM_SKB_CB(skb)->seq.output.hi; 322 323 extra->esphoff = (unsigned char *)esph - 324 skb_transport_header(skb); 325 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4); 326 extra->seqhi = esph->spi; 327 esph->seq_no = htonl(seqhi); 328 } 329 330 esph->spi = x->id.spi; 331 332 return esph; 333 } 334 335 static void esp_output_done_esn(void *data, int err) 336 { 337 struct sk_buff *skb = data; 338 339 esp_output_restore_header(skb); 340 esp_output_done(data, err); 341 } 342 343 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb, 344 int encap_type, 345 struct esp_info *esp, 346 __be16 sport, 347 __be16 dport) 348 { 349 struct udphdr *uh; 350 __be32 *udpdata32; 351 unsigned int len; 352 353 len = skb->len + esp->tailen - skb_transport_offset(skb); 354 if (len + sizeof(struct iphdr) > IP_MAX_MTU) 355 return ERR_PTR(-EMSGSIZE); 356 357 uh = (struct udphdr *)esp->esph; 358 uh->source = sport; 359 uh->dest = dport; 360 uh->len = htons(len); 361 uh->check = 0; 362 363 *skb_mac_header(skb) = IPPROTO_UDP; 364 365 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) { 366 udpdata32 = (__be32 *)(uh + 1); 367 udpdata32[0] = udpdata32[1] = 0; 368 return (struct ip_esp_hdr *)(udpdata32 + 2); 369 } 370 371 return (struct ip_esp_hdr *)(uh + 1); 372 } 373 374 #ifdef CONFIG_INET_ESPINTCP 375 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 376 struct sk_buff *skb, 377 struct esp_info *esp) 378 { 379 __be16 *lenp = (void *)esp->esph; 380 struct ip_esp_hdr *esph; 381 unsigned int len; 382 struct sock *sk; 383 384 len = skb->len + esp->tailen - skb_transport_offset(skb); 385 if (len > IP_MAX_MTU) 386 return ERR_PTR(-EMSGSIZE); 387 388 rcu_read_lock(); 389 sk = esp_find_tcp_sk(x); 390 rcu_read_unlock(); 391 392 if (IS_ERR(sk)) 393 return ERR_CAST(sk); 394 395 *lenp = htons(len); 396 esph = (struct ip_esp_hdr *)(lenp + 1); 397 398 return esph; 399 } 400 #else 401 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 402 struct sk_buff *skb, 403 struct esp_info *esp) 404 { 405 return ERR_PTR(-EOPNOTSUPP); 406 } 407 #endif 408 409 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb, 410 struct esp_info *esp) 411 { 412 struct xfrm_encap_tmpl *encap = x->encap; 413 struct ip_esp_hdr *esph; 414 __be16 sport, dport; 415 int encap_type; 416 417 spin_lock_bh(&x->lock); 418 sport = encap->encap_sport; 419 dport = encap->encap_dport; 420 encap_type = encap->encap_type; 421 spin_unlock_bh(&x->lock); 422 423 switch (encap_type) { 424 default: 425 case UDP_ENCAP_ESPINUDP: 426 case UDP_ENCAP_ESPINUDP_NON_IKE: 427 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport); 428 break; 429 case TCP_ENCAP_ESPINTCP: 430 esph = esp_output_tcp_encap(x, skb, esp); 431 break; 432 } 433 434 if (IS_ERR(esph)) 435 return PTR_ERR(esph); 436 437 esp->esph = esph; 438 439 return 0; 440 } 441 442 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 443 { 444 u8 *tail; 445 int nfrags; 446 int esph_offset; 447 struct page *page; 448 struct sk_buff *trailer; 449 int tailen = esp->tailen; 450 451 /* this is non-NULL only with TCP/UDP Encapsulation */ 452 if (x->encap) { 453 int err = esp_output_encap(x, skb, esp); 454 455 if (err < 0) 456 return err; 457 } 458 459 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE || 460 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE) 461 goto cow; 462 463 if (!skb_cloned(skb)) { 464 if (tailen <= skb_tailroom(skb)) { 465 nfrags = 1; 466 trailer = skb; 467 tail = skb_tail_pointer(trailer); 468 469 goto skip_cow; 470 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 471 && !skb_has_frag_list(skb)) { 472 int allocsize; 473 struct sock *sk = skb->sk; 474 struct page_frag *pfrag = &x->xfrag; 475 476 esp->inplace = false; 477 478 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 479 480 spin_lock_bh(&x->lock); 481 482 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 483 spin_unlock_bh(&x->lock); 484 goto cow; 485 } 486 487 page = pfrag->page; 488 get_page(page); 489 490 tail = page_address(page) + pfrag->offset; 491 492 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 493 494 nfrags = skb_shinfo(skb)->nr_frags; 495 496 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 497 tailen); 498 skb_shinfo(skb)->nr_frags = ++nfrags; 499 500 pfrag->offset = pfrag->offset + allocsize; 501 502 spin_unlock_bh(&x->lock); 503 504 nfrags++; 505 506 skb_len_add(skb, tailen); 507 if (sk && sk_fullsock(sk)) 508 refcount_add(tailen, &sk->sk_wmem_alloc); 509 510 goto out; 511 } 512 } 513 514 cow: 515 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 516 517 nfrags = skb_cow_data(skb, tailen, &trailer); 518 if (nfrags < 0) 519 goto out; 520 tail = skb_tail_pointer(trailer); 521 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 522 523 skip_cow: 524 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 525 pskb_put(skb, trailer, tailen); 526 527 out: 528 return nfrags; 529 } 530 EXPORT_SYMBOL_GPL(esp_output_head); 531 532 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 533 { 534 u8 *iv; 535 int alen; 536 void *tmp; 537 int ivlen; 538 int assoclen; 539 int extralen; 540 struct page *page; 541 struct ip_esp_hdr *esph; 542 struct crypto_aead *aead; 543 struct aead_request *req; 544 struct scatterlist *sg, *dsg; 545 struct esp_output_extra *extra; 546 int err = -ENOMEM; 547 548 assoclen = sizeof(struct ip_esp_hdr); 549 extralen = 0; 550 551 if (x->props.flags & XFRM_STATE_ESN) { 552 extralen += sizeof(*extra); 553 assoclen += sizeof(__be32); 554 } 555 556 aead = x->data; 557 alen = crypto_aead_authsize(aead); 558 ivlen = crypto_aead_ivsize(aead); 559 560 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 561 if (!tmp) 562 goto error; 563 564 extra = esp_tmp_extra(tmp); 565 iv = esp_tmp_iv(aead, tmp, extralen); 566 req = esp_tmp_req(aead, iv); 567 sg = esp_req_sg(aead, req); 568 569 if (esp->inplace) 570 dsg = sg; 571 else 572 dsg = &sg[esp->nfrags]; 573 574 esph = esp_output_set_extra(skb, x, esp->esph, extra); 575 esp->esph = esph; 576 577 sg_init_table(sg, esp->nfrags); 578 err = skb_to_sgvec(skb, sg, 579 (unsigned char *)esph - skb->data, 580 assoclen + ivlen + esp->clen + alen); 581 if (unlikely(err < 0)) 582 goto error_free; 583 584 if (!esp->inplace) { 585 int allocsize; 586 struct page_frag *pfrag = &x->xfrag; 587 588 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 589 590 spin_lock_bh(&x->lock); 591 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 592 spin_unlock_bh(&x->lock); 593 goto error_free; 594 } 595 596 skb_shinfo(skb)->nr_frags = 1; 597 598 page = pfrag->page; 599 get_page(page); 600 /* replace page frags in skb with new page */ 601 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 602 pfrag->offset = pfrag->offset + allocsize; 603 spin_unlock_bh(&x->lock); 604 605 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 606 err = skb_to_sgvec(skb, dsg, 607 (unsigned char *)esph - skb->data, 608 assoclen + ivlen + esp->clen + alen); 609 if (unlikely(err < 0)) 610 goto error_free; 611 } 612 613 if ((x->props.flags & XFRM_STATE_ESN)) 614 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 615 else 616 aead_request_set_callback(req, 0, esp_output_done, skb); 617 618 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 619 aead_request_set_ad(req, assoclen); 620 621 memset(iv, 0, ivlen); 622 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 623 min(ivlen, 8)); 624 625 ESP_SKB_CB(skb)->tmp = tmp; 626 err = crypto_aead_encrypt(req); 627 628 switch (err) { 629 case -EINPROGRESS: 630 goto error; 631 632 case -ENOSPC: 633 err = NET_XMIT_DROP; 634 break; 635 636 case 0: 637 if ((x->props.flags & XFRM_STATE_ESN)) 638 esp_output_restore_header(skb); 639 } 640 641 if (sg != dsg) 642 esp_ssg_unref(x, tmp); 643 644 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 645 err = esp_output_tail_tcp(x, skb); 646 647 error_free: 648 kfree(tmp); 649 error: 650 return err; 651 } 652 EXPORT_SYMBOL_GPL(esp_output_tail); 653 654 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 655 { 656 int alen; 657 int blksize; 658 struct ip_esp_hdr *esph; 659 struct crypto_aead *aead; 660 struct esp_info esp; 661 662 esp.inplace = true; 663 664 esp.proto = *skb_mac_header(skb); 665 *skb_mac_header(skb) = IPPROTO_ESP; 666 667 /* skb is pure payload to encrypt */ 668 669 aead = x->data; 670 alen = crypto_aead_authsize(aead); 671 672 esp.tfclen = 0; 673 if (x->tfcpad) { 674 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 675 u32 padto; 676 677 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 678 if (skb->len < padto) 679 esp.tfclen = padto - skb->len; 680 } 681 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 682 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 683 esp.plen = esp.clen - skb->len - esp.tfclen; 684 esp.tailen = esp.tfclen + esp.plen + alen; 685 686 esp.esph = ip_esp_hdr(skb); 687 688 esp.nfrags = esp_output_head(x, skb, &esp); 689 if (esp.nfrags < 0) 690 return esp.nfrags; 691 692 esph = esp.esph; 693 esph->spi = x->id.spi; 694 695 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 696 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 697 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 698 699 skb_push(skb, -skb_network_offset(skb)); 700 701 return esp_output_tail(x, skb, &esp); 702 } 703 704 static inline int esp_remove_trailer(struct sk_buff *skb) 705 { 706 struct xfrm_state *x = xfrm_input_state(skb); 707 struct crypto_aead *aead = x->data; 708 int alen, hlen, elen; 709 int padlen, trimlen; 710 __wsum csumdiff; 711 u8 nexthdr[2]; 712 int ret; 713 714 alen = crypto_aead_authsize(aead); 715 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 716 elen = skb->len - hlen; 717 718 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) 719 BUG(); 720 721 ret = -EINVAL; 722 padlen = nexthdr[0]; 723 if (padlen + 2 + alen >= elen) { 724 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 725 padlen + 2, elen - alen); 726 goto out; 727 } 728 729 trimlen = alen + padlen + 2; 730 if (skb->ip_summed == CHECKSUM_COMPLETE) { 731 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 732 skb->csum = csum_block_sub(skb->csum, csumdiff, 733 skb->len - trimlen); 734 } 735 ret = pskb_trim(skb, skb->len - trimlen); 736 if (unlikely(ret)) 737 return ret; 738 739 ret = nexthdr[1]; 740 741 out: 742 return ret; 743 } 744 745 int esp_input_done2(struct sk_buff *skb, int err) 746 { 747 const struct iphdr *iph; 748 struct xfrm_state *x = xfrm_input_state(skb); 749 struct xfrm_offload *xo = xfrm_offload(skb); 750 struct crypto_aead *aead = x->data; 751 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 752 int ihl; 753 754 if (!xo || !(xo->flags & CRYPTO_DONE)) 755 kfree(ESP_SKB_CB(skb)->tmp); 756 757 if (unlikely(err)) 758 goto out; 759 760 err = esp_remove_trailer(skb); 761 if (unlikely(err < 0)) 762 goto out; 763 764 iph = ip_hdr(skb); 765 ihl = iph->ihl * 4; 766 767 if (x->encap) { 768 struct xfrm_encap_tmpl *encap = x->encap; 769 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl); 770 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 771 __be16 source; 772 773 switch (x->encap->encap_type) { 774 case TCP_ENCAP_ESPINTCP: 775 source = th->source; 776 break; 777 case UDP_ENCAP_ESPINUDP: 778 case UDP_ENCAP_ESPINUDP_NON_IKE: 779 source = uh->source; 780 break; 781 default: 782 WARN_ON_ONCE(1); 783 err = -EINVAL; 784 goto out; 785 } 786 787 /* 788 * 1) if the NAT-T peer's IP or port changed then 789 * advertise the change to the keying daemon. 790 * This is an inbound SA, so just compare 791 * SRC ports. 792 */ 793 if (iph->saddr != x->props.saddr.a4 || 794 source != encap->encap_sport) { 795 xfrm_address_t ipaddr; 796 797 ipaddr.a4 = iph->saddr; 798 km_new_mapping(x, &ipaddr, source); 799 800 /* XXX: perhaps add an extra 801 * policy check here, to see 802 * if we should allow or 803 * reject a packet from a 804 * different source 805 * address/port. 806 */ 807 } 808 809 /* 810 * 2) ignore UDP/TCP checksums in case 811 * of NAT-T in Transport Mode, or 812 * perform other post-processing fixes 813 * as per draft-ietf-ipsec-udp-encaps-06, 814 * section 3.1.2 815 */ 816 if (x->props.mode == XFRM_MODE_TRANSPORT) 817 skb->ip_summed = CHECKSUM_UNNECESSARY; 818 } 819 820 skb_pull_rcsum(skb, hlen); 821 if (x->props.mode == XFRM_MODE_TUNNEL) 822 skb_reset_transport_header(skb); 823 else 824 skb_set_transport_header(skb, -ihl); 825 826 /* RFC4303: Drop dummy packets without any error */ 827 if (err == IPPROTO_NONE) 828 err = -EINVAL; 829 830 out: 831 return err; 832 } 833 EXPORT_SYMBOL_GPL(esp_input_done2); 834 835 static void esp_input_done(void *data, int err) 836 { 837 struct sk_buff *skb = data; 838 839 xfrm_input_resume(skb, esp_input_done2(skb, err)); 840 } 841 842 static void esp_input_restore_header(struct sk_buff *skb) 843 { 844 esp_restore_header(skb, 0); 845 __skb_pull(skb, 4); 846 } 847 848 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 849 { 850 struct xfrm_state *x = xfrm_input_state(skb); 851 struct ip_esp_hdr *esph; 852 853 /* For ESN we move the header forward by 4 bytes to 854 * accommodate the high bits. We will move it back after 855 * decryption. 856 */ 857 if ((x->props.flags & XFRM_STATE_ESN)) { 858 esph = skb_push(skb, 4); 859 *seqhi = esph->spi; 860 esph->spi = esph->seq_no; 861 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 862 } 863 } 864 865 static void esp_input_done_esn(void *data, int err) 866 { 867 struct sk_buff *skb = data; 868 869 esp_input_restore_header(skb); 870 esp_input_done(data, err); 871 } 872 873 /* 874 * Note: detecting truncated vs. non-truncated authentication data is very 875 * expensive, so we only support truncated data, which is the recommended 876 * and common case. 877 */ 878 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 879 { 880 struct crypto_aead *aead = x->data; 881 struct aead_request *req; 882 struct sk_buff *trailer; 883 int ivlen = crypto_aead_ivsize(aead); 884 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 885 int nfrags; 886 int assoclen; 887 int seqhilen; 888 __be32 *seqhi; 889 void *tmp; 890 u8 *iv; 891 struct scatterlist *sg; 892 int err = -EINVAL; 893 894 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) 895 goto out; 896 897 if (elen <= 0) 898 goto out; 899 900 assoclen = sizeof(struct ip_esp_hdr); 901 seqhilen = 0; 902 903 if (x->props.flags & XFRM_STATE_ESN) { 904 seqhilen += sizeof(__be32); 905 assoclen += seqhilen; 906 } 907 908 if (!skb_cloned(skb)) { 909 if (!skb_is_nonlinear(skb)) { 910 nfrags = 1; 911 912 goto skip_cow; 913 } else if (!skb_has_frag_list(skb)) { 914 nfrags = skb_shinfo(skb)->nr_frags; 915 nfrags++; 916 917 goto skip_cow; 918 } 919 } 920 921 err = skb_cow_data(skb, 0, &trailer); 922 if (err < 0) 923 goto out; 924 925 nfrags = err; 926 927 skip_cow: 928 err = -ENOMEM; 929 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 930 if (!tmp) 931 goto out; 932 933 ESP_SKB_CB(skb)->tmp = tmp; 934 seqhi = esp_tmp_extra(tmp); 935 iv = esp_tmp_iv(aead, tmp, seqhilen); 936 req = esp_tmp_req(aead, iv); 937 sg = esp_req_sg(aead, req); 938 939 esp_input_set_header(skb, seqhi); 940 941 sg_init_table(sg, nfrags); 942 err = skb_to_sgvec(skb, sg, 0, skb->len); 943 if (unlikely(err < 0)) { 944 kfree(tmp); 945 goto out; 946 } 947 948 skb->ip_summed = CHECKSUM_NONE; 949 950 if ((x->props.flags & XFRM_STATE_ESN)) 951 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 952 else 953 aead_request_set_callback(req, 0, esp_input_done, skb); 954 955 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 956 aead_request_set_ad(req, assoclen); 957 958 err = crypto_aead_decrypt(req); 959 if (err == -EINPROGRESS) 960 goto out; 961 962 if ((x->props.flags & XFRM_STATE_ESN)) 963 esp_input_restore_header(skb); 964 965 err = esp_input_done2(skb, err); 966 967 out: 968 return err; 969 } 970 971 static int esp4_err(struct sk_buff *skb, u32 info) 972 { 973 struct net *net = dev_net(skb->dev); 974 const struct iphdr *iph = (const struct iphdr *)skb->data; 975 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 976 struct xfrm_state *x; 977 978 switch (icmp_hdr(skb)->type) { 979 case ICMP_DEST_UNREACH: 980 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 981 return 0; 982 break; 983 case ICMP_REDIRECT: 984 break; 985 default: 986 return 0; 987 } 988 989 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 990 esph->spi, IPPROTO_ESP, AF_INET); 991 if (!x) 992 return 0; 993 994 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 995 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP); 996 else 997 ipv4_redirect(skb, net, 0, IPPROTO_ESP); 998 xfrm_state_put(x); 999 1000 return 0; 1001 } 1002 1003 static void esp_destroy(struct xfrm_state *x) 1004 { 1005 struct crypto_aead *aead = x->data; 1006 1007 if (!aead) 1008 return; 1009 1010 crypto_free_aead(aead); 1011 } 1012 1013 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 1014 { 1015 char aead_name[CRYPTO_MAX_ALG_NAME]; 1016 struct crypto_aead *aead; 1017 int err; 1018 1019 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1020 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 1021 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1022 return -ENAMETOOLONG; 1023 } 1024 1025 aead = crypto_alloc_aead(aead_name, 0, 0); 1026 err = PTR_ERR(aead); 1027 if (IS_ERR(aead)) 1028 goto error; 1029 1030 x->data = aead; 1031 1032 err = crypto_aead_setkey(aead, x->aead->alg_key, 1033 (x->aead->alg_key_len + 7) / 8); 1034 if (err) 1035 goto error; 1036 1037 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1038 if (err) 1039 goto error; 1040 1041 return 0; 1042 1043 error: 1044 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1045 return err; 1046 } 1047 1048 static int esp_init_authenc(struct xfrm_state *x, 1049 struct netlink_ext_ack *extack) 1050 { 1051 struct crypto_aead *aead; 1052 struct crypto_authenc_key_param *param; 1053 struct rtattr *rta; 1054 char *key; 1055 char *p; 1056 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1057 unsigned int keylen; 1058 int err; 1059 1060 err = -ENAMETOOLONG; 1061 1062 if ((x->props.flags & XFRM_STATE_ESN)) { 1063 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1064 "%s%sauthencesn(%s,%s)%s", 1065 x->geniv ?: "", x->geniv ? "(" : "", 1066 x->aalg ? x->aalg->alg_name : "digest_null", 1067 x->ealg->alg_name, 1068 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1069 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1070 goto error; 1071 } 1072 } else { 1073 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1074 "%s%sauthenc(%s,%s)%s", 1075 x->geniv ?: "", x->geniv ? "(" : "", 1076 x->aalg ? x->aalg->alg_name : "digest_null", 1077 x->ealg->alg_name, 1078 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1079 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1080 goto error; 1081 } 1082 } 1083 1084 aead = crypto_alloc_aead(authenc_name, 0, 0); 1085 err = PTR_ERR(aead); 1086 if (IS_ERR(aead)) { 1087 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1088 goto error; 1089 } 1090 1091 x->data = aead; 1092 1093 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1094 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1095 err = -ENOMEM; 1096 key = kmalloc(keylen, GFP_KERNEL); 1097 if (!key) 1098 goto error; 1099 1100 p = key; 1101 rta = (void *)p; 1102 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1103 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1104 param = RTA_DATA(rta); 1105 p += RTA_SPACE(sizeof(*param)); 1106 1107 if (x->aalg) { 1108 struct xfrm_algo_desc *aalg_desc; 1109 1110 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1111 p += (x->aalg->alg_key_len + 7) / 8; 1112 1113 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1114 BUG_ON(!aalg_desc); 1115 1116 err = -EINVAL; 1117 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1118 crypto_aead_authsize(aead)) { 1119 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1120 goto free_key; 1121 } 1122 1123 err = crypto_aead_setauthsize( 1124 aead, x->aalg->alg_trunc_len / 8); 1125 if (err) { 1126 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1127 goto free_key; 1128 } 1129 } 1130 1131 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1132 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1133 1134 err = crypto_aead_setkey(aead, key, keylen); 1135 1136 free_key: 1137 kfree_sensitive(key); 1138 1139 error: 1140 return err; 1141 } 1142 1143 static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1144 { 1145 struct crypto_aead *aead; 1146 u32 align; 1147 int err; 1148 1149 x->data = NULL; 1150 1151 if (x->aead) { 1152 err = esp_init_aead(x, extack); 1153 } else if (x->ealg) { 1154 err = esp_init_authenc(x, extack); 1155 } else { 1156 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1157 err = -EINVAL; 1158 } 1159 1160 if (err) 1161 goto error; 1162 1163 aead = x->data; 1164 1165 x->props.header_len = sizeof(struct ip_esp_hdr) + 1166 crypto_aead_ivsize(aead); 1167 if (x->props.mode == XFRM_MODE_TUNNEL) 1168 x->props.header_len += sizeof(struct iphdr); 1169 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 1170 x->props.header_len += IPV4_BEET_PHMAXLEN; 1171 if (x->encap) { 1172 struct xfrm_encap_tmpl *encap = x->encap; 1173 1174 switch (encap->encap_type) { 1175 default: 1176 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1177 err = -EINVAL; 1178 goto error; 1179 case UDP_ENCAP_ESPINUDP: 1180 x->props.header_len += sizeof(struct udphdr); 1181 break; 1182 case UDP_ENCAP_ESPINUDP_NON_IKE: 1183 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 1184 break; 1185 #ifdef CONFIG_INET_ESPINTCP 1186 case TCP_ENCAP_ESPINTCP: 1187 /* only the length field, TCP encap is done by 1188 * the socket 1189 */ 1190 x->props.header_len += 2; 1191 break; 1192 #endif 1193 } 1194 } 1195 1196 align = ALIGN(crypto_aead_blocksize(aead), 4); 1197 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1198 1199 error: 1200 return err; 1201 } 1202 1203 static int esp4_rcv_cb(struct sk_buff *skb, int err) 1204 { 1205 return 0; 1206 } 1207 1208 static const struct xfrm_type esp_type = 1209 { 1210 .owner = THIS_MODULE, 1211 .proto = IPPROTO_ESP, 1212 .flags = XFRM_TYPE_REPLAY_PROT, 1213 .init_state = esp_init_state, 1214 .destructor = esp_destroy, 1215 .input = esp_input, 1216 .output = esp_output, 1217 }; 1218 1219 static struct xfrm4_protocol esp4_protocol = { 1220 .handler = xfrm4_rcv, 1221 .input_handler = xfrm_input, 1222 .cb_handler = esp4_rcv_cb, 1223 .err_handler = esp4_err, 1224 .priority = 0, 1225 }; 1226 1227 static int __init esp4_init(void) 1228 { 1229 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 1230 pr_info("%s: can't add xfrm type\n", __func__); 1231 return -EAGAIN; 1232 } 1233 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 1234 pr_info("%s: can't add protocol\n", __func__); 1235 xfrm_unregister_type(&esp_type, AF_INET); 1236 return -EAGAIN; 1237 } 1238 return 0; 1239 } 1240 1241 static void __exit esp4_fini(void) 1242 { 1243 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 1244 pr_info("%s: can't remove protocol\n", __func__); 1245 xfrm_unregister_type(&esp_type, AF_INET); 1246 } 1247 1248 module_init(esp4_init); 1249 module_exit(esp4_fini); 1250 MODULE_LICENSE("GPL"); 1251 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1252