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(sg_page(sg), skb->pp_recycle); 119 } 120 121 #ifdef CONFIG_INET_ESPINTCP 122 struct esp_tcp_sk { 123 struct sock *sk; 124 struct rcu_head rcu; 125 }; 126 127 static void esp_free_tcp_sk(struct rcu_head *head) 128 { 129 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu); 130 131 sock_put(esk->sk); 132 kfree(esk); 133 } 134 135 static struct sock *esp_find_tcp_sk(struct xfrm_state *x) 136 { 137 struct xfrm_encap_tmpl *encap = x->encap; 138 struct net *net = xs_net(x); 139 struct esp_tcp_sk *esk; 140 __be16 sport, dport; 141 struct sock *nsk; 142 struct sock *sk; 143 144 sk = rcu_dereference(x->encap_sk); 145 if (sk && sk->sk_state == TCP_ESTABLISHED) 146 return sk; 147 148 spin_lock_bh(&x->lock); 149 sport = encap->encap_sport; 150 dport = encap->encap_dport; 151 nsk = rcu_dereference_protected(x->encap_sk, 152 lockdep_is_held(&x->lock)); 153 if (sk && sk == nsk) { 154 esk = kmalloc(sizeof(*esk), GFP_ATOMIC); 155 if (!esk) { 156 spin_unlock_bh(&x->lock); 157 return ERR_PTR(-ENOMEM); 158 } 159 RCU_INIT_POINTER(x->encap_sk, NULL); 160 esk->sk = sk; 161 call_rcu(&esk->rcu, esp_free_tcp_sk); 162 } 163 spin_unlock_bh(&x->lock); 164 165 sk = inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, x->id.daddr.a4, 166 dport, x->props.saddr.a4, sport, 0); 167 if (!sk) 168 return ERR_PTR(-ENOENT); 169 170 if (!tcp_is_ulp_esp(sk)) { 171 sock_put(sk); 172 return ERR_PTR(-EINVAL); 173 } 174 175 spin_lock_bh(&x->lock); 176 nsk = rcu_dereference_protected(x->encap_sk, 177 lockdep_is_held(&x->lock)); 178 if (encap->encap_sport != sport || 179 encap->encap_dport != dport) { 180 sock_put(sk); 181 sk = nsk ?: ERR_PTR(-EREMCHG); 182 } else if (sk == nsk) { 183 sock_put(sk); 184 } else { 185 rcu_assign_pointer(x->encap_sk, sk); 186 } 187 spin_unlock_bh(&x->lock); 188 189 return sk; 190 } 191 192 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) 193 { 194 struct sock *sk; 195 int err; 196 197 rcu_read_lock(); 198 199 sk = esp_find_tcp_sk(x); 200 err = PTR_ERR_OR_ZERO(sk); 201 if (err) 202 goto out; 203 204 bh_lock_sock(sk); 205 if (sock_owned_by_user(sk)) 206 err = espintcp_queue_out(sk, skb); 207 else 208 err = espintcp_push_skb(sk, skb); 209 bh_unlock_sock(sk); 210 211 out: 212 rcu_read_unlock(); 213 return err; 214 } 215 216 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk, 217 struct sk_buff *skb) 218 { 219 struct dst_entry *dst = skb_dst(skb); 220 struct xfrm_state *x = dst->xfrm; 221 222 return esp_output_tcp_finish(x, skb); 223 } 224 225 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 226 { 227 int err; 228 229 local_bh_disable(); 230 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb); 231 local_bh_enable(); 232 233 /* EINPROGRESS just happens to do the right thing. It 234 * actually means that the skb has been consumed and 235 * isn't coming back. 236 */ 237 return err ?: -EINPROGRESS; 238 } 239 #else 240 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 241 { 242 kfree_skb(skb); 243 244 return -EOPNOTSUPP; 245 } 246 #endif 247 248 static void esp_output_done(void *data, int err) 249 { 250 struct sk_buff *skb = data; 251 struct xfrm_offload *xo = xfrm_offload(skb); 252 void *tmp; 253 struct xfrm_state *x; 254 255 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 256 struct sec_path *sp = skb_sec_path(skb); 257 258 x = sp->xvec[sp->len - 1]; 259 } else { 260 x = skb_dst(skb)->xfrm; 261 } 262 263 tmp = ESP_SKB_CB(skb)->tmp; 264 esp_ssg_unref(x, tmp, skb); 265 kfree(tmp); 266 267 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 268 if (err) { 269 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR); 270 kfree_skb(skb); 271 return; 272 } 273 274 skb_push(skb, skb->data - skb_mac_header(skb)); 275 secpath_reset(skb); 276 xfrm_dev_resume(skb); 277 } else { 278 if (!err && 279 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 280 esp_output_tail_tcp(x, skb); 281 else 282 xfrm_output_resume(skb->sk, skb, err); 283 } 284 } 285 286 /* Move ESP header back into place. */ 287 static void esp_restore_header(struct sk_buff *skb, unsigned int offset) 288 { 289 struct ip_esp_hdr *esph = (void *)(skb->data + offset); 290 void *tmp = ESP_SKB_CB(skb)->tmp; 291 __be32 *seqhi = esp_tmp_extra(tmp); 292 293 esph->seq_no = esph->spi; 294 esph->spi = *seqhi; 295 } 296 297 static void esp_output_restore_header(struct sk_buff *skb) 298 { 299 void *tmp = ESP_SKB_CB(skb)->tmp; 300 struct esp_output_extra *extra = esp_tmp_extra(tmp); 301 302 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff - 303 sizeof(__be32)); 304 } 305 306 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb, 307 struct xfrm_state *x, 308 struct ip_esp_hdr *esph, 309 struct esp_output_extra *extra) 310 { 311 /* For ESN we move the header forward by 4 bytes to 312 * accommodate the high bits. We will move it back after 313 * encryption. 314 */ 315 if ((x->props.flags & XFRM_STATE_ESN)) { 316 __u32 seqhi; 317 struct xfrm_offload *xo = xfrm_offload(skb); 318 319 if (xo) 320 seqhi = xo->seq.hi; 321 else 322 seqhi = XFRM_SKB_CB(skb)->seq.output.hi; 323 324 extra->esphoff = (unsigned char *)esph - 325 skb_transport_header(skb); 326 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4); 327 extra->seqhi = esph->spi; 328 esph->seq_no = htonl(seqhi); 329 } 330 331 esph->spi = x->id.spi; 332 333 return esph; 334 } 335 336 static void esp_output_done_esn(void *data, int err) 337 { 338 struct sk_buff *skb = data; 339 340 esp_output_restore_header(skb); 341 esp_output_done(data, err); 342 } 343 344 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb, 345 int encap_type, 346 struct esp_info *esp, 347 __be16 sport, 348 __be16 dport) 349 { 350 struct udphdr *uh; 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 return (struct ip_esp_hdr *)(uh + 1); 366 } 367 368 #ifdef CONFIG_INET_ESPINTCP 369 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 370 struct sk_buff *skb, 371 struct esp_info *esp) 372 { 373 __be16 *lenp = (void *)esp->esph; 374 struct ip_esp_hdr *esph; 375 unsigned int len; 376 struct sock *sk; 377 378 len = skb->len + esp->tailen - skb_transport_offset(skb); 379 if (len > IP_MAX_MTU) 380 return ERR_PTR(-EMSGSIZE); 381 382 rcu_read_lock(); 383 sk = esp_find_tcp_sk(x); 384 rcu_read_unlock(); 385 386 if (IS_ERR(sk)) 387 return ERR_CAST(sk); 388 389 *lenp = htons(len); 390 esph = (struct ip_esp_hdr *)(lenp + 1); 391 392 return esph; 393 } 394 #else 395 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 396 struct sk_buff *skb, 397 struct esp_info *esp) 398 { 399 return ERR_PTR(-EOPNOTSUPP); 400 } 401 #endif 402 403 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb, 404 struct esp_info *esp) 405 { 406 struct xfrm_encap_tmpl *encap = x->encap; 407 struct ip_esp_hdr *esph; 408 __be16 sport, dport; 409 int encap_type; 410 411 spin_lock_bh(&x->lock); 412 sport = encap->encap_sport; 413 dport = encap->encap_dport; 414 encap_type = encap->encap_type; 415 spin_unlock_bh(&x->lock); 416 417 switch (encap_type) { 418 default: 419 case UDP_ENCAP_ESPINUDP: 420 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport); 421 break; 422 case TCP_ENCAP_ESPINTCP: 423 esph = esp_output_tcp_encap(x, skb, esp); 424 break; 425 } 426 427 if (IS_ERR(esph)) 428 return PTR_ERR(esph); 429 430 esp->esph = esph; 431 432 return 0; 433 } 434 435 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 436 { 437 u8 *tail; 438 int nfrags; 439 int esph_offset; 440 struct page *page; 441 struct sk_buff *trailer; 442 int tailen = esp->tailen; 443 444 /* this is non-NULL only with TCP/UDP Encapsulation */ 445 if (x->encap) { 446 int err = esp_output_encap(x, skb, esp); 447 448 if (err < 0) 449 return err; 450 } 451 452 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE || 453 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE) 454 goto cow; 455 456 if (!skb_cloned(skb)) { 457 if (tailen <= skb_tailroom(skb)) { 458 nfrags = 1; 459 trailer = skb; 460 tail = skb_tail_pointer(trailer); 461 462 goto skip_cow; 463 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 464 && !skb_has_frag_list(skb)) { 465 int allocsize; 466 struct sock *sk = skb->sk; 467 struct page_frag *pfrag = &x->xfrag; 468 469 esp->inplace = false; 470 471 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 472 473 spin_lock_bh(&x->lock); 474 475 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 476 spin_unlock_bh(&x->lock); 477 goto cow; 478 } 479 480 page = pfrag->page; 481 get_page(page); 482 483 tail = page_address(page) + pfrag->offset; 484 485 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 486 487 nfrags = skb_shinfo(skb)->nr_frags; 488 489 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 490 tailen); 491 skb_shinfo(skb)->nr_frags = ++nfrags; 492 493 pfrag->offset = pfrag->offset + allocsize; 494 495 spin_unlock_bh(&x->lock); 496 497 nfrags++; 498 499 skb_len_add(skb, tailen); 500 if (sk && sk_fullsock(sk)) 501 refcount_add(tailen, &sk->sk_wmem_alloc); 502 503 goto out; 504 } 505 } 506 507 cow: 508 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 509 510 nfrags = skb_cow_data(skb, tailen, &trailer); 511 if (nfrags < 0) 512 goto out; 513 tail = skb_tail_pointer(trailer); 514 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 515 516 skip_cow: 517 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 518 pskb_put(skb, trailer, tailen); 519 520 out: 521 return nfrags; 522 } 523 EXPORT_SYMBOL_GPL(esp_output_head); 524 525 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 526 { 527 u8 *iv; 528 int alen; 529 void *tmp; 530 int ivlen; 531 int assoclen; 532 int extralen; 533 struct page *page; 534 struct ip_esp_hdr *esph; 535 struct crypto_aead *aead; 536 struct aead_request *req; 537 struct scatterlist *sg, *dsg; 538 struct esp_output_extra *extra; 539 int err = -ENOMEM; 540 541 assoclen = sizeof(struct ip_esp_hdr); 542 extralen = 0; 543 544 if (x->props.flags & XFRM_STATE_ESN) { 545 extralen += sizeof(*extra); 546 assoclen += sizeof(__be32); 547 } 548 549 aead = x->data; 550 alen = crypto_aead_authsize(aead); 551 ivlen = crypto_aead_ivsize(aead); 552 553 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 554 if (!tmp) 555 goto error; 556 557 extra = esp_tmp_extra(tmp); 558 iv = esp_tmp_iv(aead, tmp, extralen); 559 req = esp_tmp_req(aead, iv); 560 sg = esp_req_sg(aead, req); 561 562 if (esp->inplace) 563 dsg = sg; 564 else 565 dsg = &sg[esp->nfrags]; 566 567 esph = esp_output_set_extra(skb, x, esp->esph, extra); 568 esp->esph = esph; 569 570 sg_init_table(sg, esp->nfrags); 571 err = skb_to_sgvec(skb, sg, 572 (unsigned char *)esph - skb->data, 573 assoclen + ivlen + esp->clen + alen); 574 if (unlikely(err < 0)) 575 goto error_free; 576 577 if (!esp->inplace) { 578 int allocsize; 579 struct page_frag *pfrag = &x->xfrag; 580 581 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 582 583 spin_lock_bh(&x->lock); 584 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 585 spin_unlock_bh(&x->lock); 586 goto error_free; 587 } 588 589 skb_shinfo(skb)->nr_frags = 1; 590 591 page = pfrag->page; 592 get_page(page); 593 /* replace page frags in skb with new page */ 594 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 595 pfrag->offset = pfrag->offset + allocsize; 596 spin_unlock_bh(&x->lock); 597 598 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 599 err = skb_to_sgvec(skb, dsg, 600 (unsigned char *)esph - skb->data, 601 assoclen + ivlen + esp->clen + alen); 602 if (unlikely(err < 0)) 603 goto error_free; 604 } 605 606 if ((x->props.flags & XFRM_STATE_ESN)) 607 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 608 else 609 aead_request_set_callback(req, 0, esp_output_done, skb); 610 611 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 612 aead_request_set_ad(req, assoclen); 613 614 memset(iv, 0, ivlen); 615 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 616 min(ivlen, 8)); 617 618 ESP_SKB_CB(skb)->tmp = tmp; 619 err = crypto_aead_encrypt(req); 620 621 switch (err) { 622 case -EINPROGRESS: 623 goto error; 624 625 case -ENOSPC: 626 err = NET_XMIT_DROP; 627 break; 628 629 case 0: 630 if ((x->props.flags & XFRM_STATE_ESN)) 631 esp_output_restore_header(skb); 632 } 633 634 if (sg != dsg) 635 esp_ssg_unref(x, tmp, skb); 636 637 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 638 err = esp_output_tail_tcp(x, skb); 639 640 error_free: 641 kfree(tmp); 642 error: 643 return err; 644 } 645 EXPORT_SYMBOL_GPL(esp_output_tail); 646 647 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 648 { 649 int alen; 650 int blksize; 651 struct ip_esp_hdr *esph; 652 struct crypto_aead *aead; 653 struct esp_info esp; 654 655 esp.inplace = true; 656 657 esp.proto = *skb_mac_header(skb); 658 *skb_mac_header(skb) = IPPROTO_ESP; 659 660 /* skb is pure payload to encrypt */ 661 662 aead = x->data; 663 alen = crypto_aead_authsize(aead); 664 665 esp.tfclen = 0; 666 if (x->tfcpad) { 667 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 668 u32 padto; 669 670 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 671 if (skb->len < padto) 672 esp.tfclen = padto - skb->len; 673 } 674 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 675 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 676 esp.plen = esp.clen - skb->len - esp.tfclen; 677 esp.tailen = esp.tfclen + esp.plen + alen; 678 679 esp.esph = ip_esp_hdr(skb); 680 681 esp.nfrags = esp_output_head(x, skb, &esp); 682 if (esp.nfrags < 0) 683 return esp.nfrags; 684 685 esph = esp.esph; 686 esph->spi = x->id.spi; 687 688 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 689 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 690 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 691 692 skb_push(skb, -skb_network_offset(skb)); 693 694 return esp_output_tail(x, skb, &esp); 695 } 696 697 static inline int esp_remove_trailer(struct sk_buff *skb) 698 { 699 struct xfrm_state *x = xfrm_input_state(skb); 700 struct crypto_aead *aead = x->data; 701 int alen, hlen, elen; 702 int padlen, trimlen; 703 __wsum csumdiff; 704 u8 nexthdr[2]; 705 int ret; 706 707 alen = crypto_aead_authsize(aead); 708 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 709 elen = skb->len - hlen; 710 711 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) 712 BUG(); 713 714 ret = -EINVAL; 715 padlen = nexthdr[0]; 716 if (padlen + 2 + alen >= elen) { 717 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 718 padlen + 2, elen - alen); 719 goto out; 720 } 721 722 trimlen = alen + padlen + 2; 723 if (skb->ip_summed == CHECKSUM_COMPLETE) { 724 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 725 skb->csum = csum_block_sub(skb->csum, csumdiff, 726 skb->len - trimlen); 727 } 728 ret = pskb_trim(skb, skb->len - trimlen); 729 if (unlikely(ret)) 730 return ret; 731 732 ret = nexthdr[1]; 733 734 out: 735 return ret; 736 } 737 738 int esp_input_done2(struct sk_buff *skb, int err) 739 { 740 const struct iphdr *iph; 741 struct xfrm_state *x = xfrm_input_state(skb); 742 struct xfrm_offload *xo = xfrm_offload(skb); 743 struct crypto_aead *aead = x->data; 744 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 745 int ihl; 746 747 if (!xo || !(xo->flags & CRYPTO_DONE)) 748 kfree(ESP_SKB_CB(skb)->tmp); 749 750 if (unlikely(err)) 751 goto out; 752 753 err = esp_remove_trailer(skb); 754 if (unlikely(err < 0)) 755 goto out; 756 757 iph = ip_hdr(skb); 758 ihl = iph->ihl * 4; 759 760 if (x->encap) { 761 struct xfrm_encap_tmpl *encap = x->encap; 762 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl); 763 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 764 __be16 source; 765 766 switch (x->encap->encap_type) { 767 case TCP_ENCAP_ESPINTCP: 768 source = th->source; 769 break; 770 case UDP_ENCAP_ESPINUDP: 771 source = uh->source; 772 break; 773 default: 774 WARN_ON_ONCE(1); 775 err = -EINVAL; 776 goto out; 777 } 778 779 /* 780 * 1) if the NAT-T peer's IP or port changed then 781 * advertise the change to the keying daemon. 782 * This is an inbound SA, so just compare 783 * SRC ports. 784 */ 785 if (iph->saddr != x->props.saddr.a4 || 786 source != encap->encap_sport) { 787 xfrm_address_t ipaddr; 788 789 ipaddr.a4 = iph->saddr; 790 km_new_mapping(x, &ipaddr, source); 791 792 /* XXX: perhaps add an extra 793 * policy check here, to see 794 * if we should allow or 795 * reject a packet from a 796 * different source 797 * address/port. 798 */ 799 } 800 801 /* 802 * 2) ignore UDP/TCP checksums in case 803 * of NAT-T in Transport Mode, or 804 * perform other post-processing fixes 805 * as per draft-ietf-ipsec-udp-encaps-06, 806 * section 3.1.2 807 */ 808 if (x->props.mode == XFRM_MODE_TRANSPORT) 809 skb->ip_summed = CHECKSUM_UNNECESSARY; 810 } 811 812 skb_pull_rcsum(skb, hlen); 813 if (x->props.mode == XFRM_MODE_TUNNEL) 814 skb_reset_transport_header(skb); 815 else 816 skb_set_transport_header(skb, -ihl); 817 818 /* RFC4303: Drop dummy packets without any error */ 819 if (err == IPPROTO_NONE) 820 err = -EINVAL; 821 822 out: 823 return err; 824 } 825 EXPORT_SYMBOL_GPL(esp_input_done2); 826 827 static void esp_input_done(void *data, int err) 828 { 829 struct sk_buff *skb = data; 830 831 xfrm_input_resume(skb, esp_input_done2(skb, err)); 832 } 833 834 static void esp_input_restore_header(struct sk_buff *skb) 835 { 836 esp_restore_header(skb, 0); 837 __skb_pull(skb, 4); 838 } 839 840 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 841 { 842 struct xfrm_state *x = xfrm_input_state(skb); 843 struct ip_esp_hdr *esph; 844 845 /* For ESN we move the header forward by 4 bytes to 846 * accommodate the high bits. We will move it back after 847 * decryption. 848 */ 849 if ((x->props.flags & XFRM_STATE_ESN)) { 850 esph = skb_push(skb, 4); 851 *seqhi = esph->spi; 852 esph->spi = esph->seq_no; 853 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 854 } 855 } 856 857 static void esp_input_done_esn(void *data, int err) 858 { 859 struct sk_buff *skb = data; 860 861 esp_input_restore_header(skb); 862 esp_input_done(data, err); 863 } 864 865 /* 866 * Note: detecting truncated vs. non-truncated authentication data is very 867 * expensive, so we only support truncated data, which is the recommended 868 * and common case. 869 */ 870 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 871 { 872 struct crypto_aead *aead = x->data; 873 struct aead_request *req; 874 struct sk_buff *trailer; 875 int ivlen = crypto_aead_ivsize(aead); 876 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 877 int nfrags; 878 int assoclen; 879 int seqhilen; 880 __be32 *seqhi; 881 void *tmp; 882 u8 *iv; 883 struct scatterlist *sg; 884 int err = -EINVAL; 885 886 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) 887 goto out; 888 889 if (elen <= 0) 890 goto out; 891 892 assoclen = sizeof(struct ip_esp_hdr); 893 seqhilen = 0; 894 895 if (x->props.flags & XFRM_STATE_ESN) { 896 seqhilen += sizeof(__be32); 897 assoclen += seqhilen; 898 } 899 900 if (!skb_cloned(skb)) { 901 if (!skb_is_nonlinear(skb)) { 902 nfrags = 1; 903 904 goto skip_cow; 905 } else if (!skb_has_frag_list(skb)) { 906 nfrags = skb_shinfo(skb)->nr_frags; 907 nfrags++; 908 909 goto skip_cow; 910 } 911 } 912 913 err = skb_cow_data(skb, 0, &trailer); 914 if (err < 0) 915 goto out; 916 917 nfrags = err; 918 919 skip_cow: 920 err = -ENOMEM; 921 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 922 if (!tmp) 923 goto out; 924 925 ESP_SKB_CB(skb)->tmp = tmp; 926 seqhi = esp_tmp_extra(tmp); 927 iv = esp_tmp_iv(aead, tmp, seqhilen); 928 req = esp_tmp_req(aead, iv); 929 sg = esp_req_sg(aead, req); 930 931 esp_input_set_header(skb, seqhi); 932 933 sg_init_table(sg, nfrags); 934 err = skb_to_sgvec(skb, sg, 0, skb->len); 935 if (unlikely(err < 0)) { 936 kfree(tmp); 937 goto out; 938 } 939 940 skb->ip_summed = CHECKSUM_NONE; 941 942 if ((x->props.flags & XFRM_STATE_ESN)) 943 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 944 else 945 aead_request_set_callback(req, 0, esp_input_done, skb); 946 947 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 948 aead_request_set_ad(req, assoclen); 949 950 err = crypto_aead_decrypt(req); 951 if (err == -EINPROGRESS) 952 goto out; 953 954 if ((x->props.flags & XFRM_STATE_ESN)) 955 esp_input_restore_header(skb); 956 957 err = esp_input_done2(skb, err); 958 959 out: 960 return err; 961 } 962 963 static int esp4_err(struct sk_buff *skb, u32 info) 964 { 965 struct net *net = dev_net(skb->dev); 966 const struct iphdr *iph = (const struct iphdr *)skb->data; 967 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 968 struct xfrm_state *x; 969 970 switch (icmp_hdr(skb)->type) { 971 case ICMP_DEST_UNREACH: 972 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 973 return 0; 974 break; 975 case ICMP_REDIRECT: 976 break; 977 default: 978 return 0; 979 } 980 981 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 982 esph->spi, IPPROTO_ESP, AF_INET); 983 if (!x) 984 return 0; 985 986 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 987 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP); 988 else 989 ipv4_redirect(skb, net, 0, IPPROTO_ESP); 990 xfrm_state_put(x); 991 992 return 0; 993 } 994 995 static void esp_destroy(struct xfrm_state *x) 996 { 997 struct crypto_aead *aead = x->data; 998 999 if (!aead) 1000 return; 1001 1002 crypto_free_aead(aead); 1003 } 1004 1005 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 1006 { 1007 char aead_name[CRYPTO_MAX_ALG_NAME]; 1008 struct crypto_aead *aead; 1009 int err; 1010 1011 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1012 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 1013 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1014 return -ENAMETOOLONG; 1015 } 1016 1017 aead = crypto_alloc_aead(aead_name, 0, 0); 1018 err = PTR_ERR(aead); 1019 if (IS_ERR(aead)) 1020 goto error; 1021 1022 x->data = aead; 1023 1024 err = crypto_aead_setkey(aead, x->aead->alg_key, 1025 (x->aead->alg_key_len + 7) / 8); 1026 if (err) 1027 goto error; 1028 1029 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1030 if (err) 1031 goto error; 1032 1033 return 0; 1034 1035 error: 1036 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1037 return err; 1038 } 1039 1040 static int esp_init_authenc(struct xfrm_state *x, 1041 struct netlink_ext_ack *extack) 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 = -ENAMETOOLONG; 1053 1054 if ((x->props.flags & XFRM_STATE_ESN)) { 1055 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1056 "%s%sauthencesn(%s,%s)%s", 1057 x->geniv ?: "", x->geniv ? "(" : "", 1058 x->aalg ? x->aalg->alg_name : "digest_null", 1059 x->ealg->alg_name, 1060 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1061 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1062 goto error; 1063 } 1064 } else { 1065 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1066 "%s%sauthenc(%s,%s)%s", 1067 x->geniv ?: "", x->geniv ? "(" : "", 1068 x->aalg ? x->aalg->alg_name : "digest_null", 1069 x->ealg->alg_name, 1070 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1071 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1072 goto error; 1073 } 1074 } 1075 1076 aead = crypto_alloc_aead(authenc_name, 0, 0); 1077 err = PTR_ERR(aead); 1078 if (IS_ERR(aead)) { 1079 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1080 goto error; 1081 } 1082 1083 x->data = aead; 1084 1085 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1086 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1087 err = -ENOMEM; 1088 key = kmalloc(keylen, GFP_KERNEL); 1089 if (!key) 1090 goto error; 1091 1092 p = key; 1093 rta = (void *)p; 1094 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1095 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1096 param = RTA_DATA(rta); 1097 p += RTA_SPACE(sizeof(*param)); 1098 1099 if (x->aalg) { 1100 struct xfrm_algo_desc *aalg_desc; 1101 1102 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1103 p += (x->aalg->alg_key_len + 7) / 8; 1104 1105 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1106 BUG_ON(!aalg_desc); 1107 1108 err = -EINVAL; 1109 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1110 crypto_aead_authsize(aead)) { 1111 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1112 goto free_key; 1113 } 1114 1115 err = crypto_aead_setauthsize( 1116 aead, x->aalg->alg_trunc_len / 8); 1117 if (err) { 1118 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1119 goto free_key; 1120 } 1121 } 1122 1123 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1124 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1125 1126 err = crypto_aead_setkey(aead, key, keylen); 1127 1128 free_key: 1129 kfree_sensitive(key); 1130 1131 error: 1132 return err; 1133 } 1134 1135 static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1136 { 1137 struct crypto_aead *aead; 1138 u32 align; 1139 int err; 1140 1141 x->data = NULL; 1142 1143 if (x->aead) { 1144 err = esp_init_aead(x, extack); 1145 } else if (x->ealg) { 1146 err = esp_init_authenc(x, extack); 1147 } else { 1148 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1149 err = -EINVAL; 1150 } 1151 1152 if (err) 1153 goto error; 1154 1155 aead = x->data; 1156 1157 x->props.header_len = sizeof(struct ip_esp_hdr) + 1158 crypto_aead_ivsize(aead); 1159 if (x->props.mode == XFRM_MODE_TUNNEL) 1160 x->props.header_len += sizeof(struct iphdr); 1161 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 1162 x->props.header_len += IPV4_BEET_PHMAXLEN; 1163 if (x->encap) { 1164 struct xfrm_encap_tmpl *encap = x->encap; 1165 1166 switch (encap->encap_type) { 1167 default: 1168 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1169 err = -EINVAL; 1170 goto error; 1171 case UDP_ENCAP_ESPINUDP: 1172 x->props.header_len += sizeof(struct udphdr); 1173 break; 1174 #ifdef CONFIG_INET_ESPINTCP 1175 case TCP_ENCAP_ESPINTCP: 1176 /* only the length field, TCP encap is done by 1177 * the socket 1178 */ 1179 x->props.header_len += 2; 1180 break; 1181 #endif 1182 } 1183 } 1184 1185 align = ALIGN(crypto_aead_blocksize(aead), 4); 1186 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1187 1188 error: 1189 return err; 1190 } 1191 1192 static int esp4_rcv_cb(struct sk_buff *skb, int err) 1193 { 1194 return 0; 1195 } 1196 1197 static const struct xfrm_type esp_type = 1198 { 1199 .owner = THIS_MODULE, 1200 .proto = IPPROTO_ESP, 1201 .flags = XFRM_TYPE_REPLAY_PROT, 1202 .init_state = esp_init_state, 1203 .destructor = esp_destroy, 1204 .input = esp_input, 1205 .output = esp_output, 1206 }; 1207 1208 static struct xfrm4_protocol esp4_protocol = { 1209 .handler = xfrm4_rcv, 1210 .input_handler = xfrm_input, 1211 .cb_handler = esp4_rcv_cb, 1212 .err_handler = esp4_err, 1213 .priority = 0, 1214 }; 1215 1216 static int __init esp4_init(void) 1217 { 1218 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 1219 pr_info("%s: can't add xfrm type\n", __func__); 1220 return -EAGAIN; 1221 } 1222 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 1223 pr_info("%s: can't add protocol\n", __func__); 1224 xfrm_unregister_type(&esp_type, AF_INET); 1225 return -EAGAIN; 1226 } 1227 return 0; 1228 } 1229 1230 static void __exit esp4_fini(void) 1231 { 1232 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 1233 pr_info("%s: can't remove protocol\n", __func__); 1234 xfrm_unregister_type(&esp_type, AF_INET); 1235 } 1236 1237 module_init(esp4_init); 1238 module_exit(esp4_fini); 1239 MODULE_DESCRIPTION("IPv4 ESP transformation library"); 1240 MODULE_LICENSE("GPL"); 1241 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1242