1 // SPDX-License-Identifier: GPL-2.0-only 2 #define pr_fmt(fmt) "IPsec: " fmt 3 4 #include <crypto/aead.h> 5 #include <crypto/authenc.h> 6 #include <linux/err.h> 7 #include <linux/module.h> 8 #include <net/ip.h> 9 #include <net/xfrm.h> 10 #include <net/esp.h> 11 #include <linux/scatterlist.h> 12 #include <linux/kernel.h> 13 #include <linux/pfkeyv2.h> 14 #include <linux/rtnetlink.h> 15 #include <linux/slab.h> 16 #include <linux/spinlock.h> 17 #include <linux/in6.h> 18 #include <net/icmp.h> 19 #include <net/protocol.h> 20 #include <net/udp.h> 21 #include <net/tcp.h> 22 #include <net/espintcp.h> 23 #include <linux/skbuff_ref.h> 24 25 #include <linux/highmem.h> 26 27 struct esp_skb_cb { 28 struct xfrm_skb_cb xfrm; 29 void *tmp; 30 }; 31 32 struct esp_output_extra { 33 __be32 seqhi; 34 u32 esphoff; 35 }; 36 37 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0])) 38 39 /* 40 * Allocate an AEAD request structure with extra space for SG and IV. 41 * 42 * For alignment considerations the IV is placed at the front, followed 43 * by the request and finally the SG list. 44 * 45 * TODO: Use spare space in skb for this where possible. 46 */ 47 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen) 48 { 49 unsigned int len; 50 51 len = extralen; 52 53 len += crypto_aead_ivsize(aead); 54 55 if (len) { 56 len += crypto_aead_alignmask(aead) & 57 ~(crypto_tfm_ctx_alignment() - 1); 58 len = ALIGN(len, crypto_tfm_ctx_alignment()); 59 } 60 61 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead); 62 len = ALIGN(len, __alignof__(struct scatterlist)); 63 64 len += sizeof(struct scatterlist) * nfrags; 65 66 return kmalloc(len, GFP_ATOMIC); 67 } 68 69 static inline void *esp_tmp_extra(void *tmp) 70 { 71 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra)); 72 } 73 74 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen) 75 { 76 return crypto_aead_ivsize(aead) ? 77 PTR_ALIGN((u8 *)tmp + extralen, 78 crypto_aead_alignmask(aead) + 1) : tmp + extralen; 79 } 80 81 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv) 82 { 83 struct aead_request *req; 84 85 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead), 86 crypto_tfm_ctx_alignment()); 87 aead_request_set_tfm(req, aead); 88 return req; 89 } 90 91 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead, 92 struct aead_request *req) 93 { 94 return (void *)ALIGN((unsigned long)(req + 1) + 95 crypto_aead_reqsize(aead), 96 __alignof__(struct scatterlist)); 97 } 98 99 static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb) 100 { 101 struct crypto_aead *aead = x->data; 102 int extralen = 0; 103 u8 *iv; 104 struct aead_request *req; 105 struct scatterlist *sg; 106 107 if (x->props.flags & XFRM_STATE_ESN) 108 extralen += sizeof(struct esp_output_extra); 109 110 iv = esp_tmp_iv(aead, tmp, extralen); 111 req = esp_tmp_req(aead, iv); 112 113 /* Unref skb_frag_pages in the src scatterlist if necessary. 114 * Skip the first sg which comes from skb->data. 115 */ 116 if (req->src != req->dst) 117 for (sg = sg_next(req->src); sg; sg = sg_next(sg)) 118 skb_page_unref(page_to_netmem(sg_page(sg)), 119 skb->pp_recycle); 120 } 121 122 #ifdef CONFIG_INET_ESPINTCP 123 struct esp_tcp_sk { 124 struct sock *sk; 125 struct rcu_head rcu; 126 }; 127 128 static void esp_free_tcp_sk(struct rcu_head *head) 129 { 130 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu); 131 132 sock_put(esk->sk); 133 kfree(esk); 134 } 135 136 static struct sock *esp_find_tcp_sk(struct xfrm_state *x) 137 { 138 struct xfrm_encap_tmpl *encap = x->encap; 139 struct net *net = xs_net(x); 140 struct esp_tcp_sk *esk; 141 __be16 sport, dport; 142 struct sock *nsk; 143 struct sock *sk; 144 145 sk = rcu_dereference(x->encap_sk); 146 if (sk && sk->sk_state == TCP_ESTABLISHED) 147 return sk; 148 149 spin_lock_bh(&x->lock); 150 sport = encap->encap_sport; 151 dport = encap->encap_dport; 152 nsk = rcu_dereference_protected(x->encap_sk, 153 lockdep_is_held(&x->lock)); 154 if (sk && sk == nsk) { 155 esk = kmalloc(sizeof(*esk), GFP_ATOMIC); 156 if (!esk) { 157 spin_unlock_bh(&x->lock); 158 return ERR_PTR(-ENOMEM); 159 } 160 RCU_INIT_POINTER(x->encap_sk, NULL); 161 esk->sk = sk; 162 call_rcu(&esk->rcu, esp_free_tcp_sk); 163 } 164 spin_unlock_bh(&x->lock); 165 166 sk = inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, x->id.daddr.a4, 167 dport, x->props.saddr.a4, sport, 0); 168 if (!sk) 169 return ERR_PTR(-ENOENT); 170 171 if (!tcp_is_ulp_esp(sk)) { 172 sock_put(sk); 173 return ERR_PTR(-EINVAL); 174 } 175 176 spin_lock_bh(&x->lock); 177 nsk = rcu_dereference_protected(x->encap_sk, 178 lockdep_is_held(&x->lock)); 179 if (encap->encap_sport != sport || 180 encap->encap_dport != dport) { 181 sock_put(sk); 182 sk = nsk ?: ERR_PTR(-EREMCHG); 183 } else if (sk == nsk) { 184 sock_put(sk); 185 } else { 186 rcu_assign_pointer(x->encap_sk, sk); 187 } 188 spin_unlock_bh(&x->lock); 189 190 return sk; 191 } 192 193 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) 194 { 195 struct sock *sk; 196 int err; 197 198 rcu_read_lock(); 199 200 sk = esp_find_tcp_sk(x); 201 err = PTR_ERR_OR_ZERO(sk); 202 if (err) 203 goto out; 204 205 bh_lock_sock(sk); 206 if (sock_owned_by_user(sk)) 207 err = espintcp_queue_out(sk, skb); 208 else 209 err = espintcp_push_skb(sk, skb); 210 bh_unlock_sock(sk); 211 212 out: 213 rcu_read_unlock(); 214 return err; 215 } 216 217 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk, 218 struct sk_buff *skb) 219 { 220 struct dst_entry *dst = skb_dst(skb); 221 struct xfrm_state *x = dst->xfrm; 222 223 return esp_output_tcp_finish(x, skb); 224 } 225 226 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 227 { 228 int err; 229 230 local_bh_disable(); 231 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb); 232 local_bh_enable(); 233 234 /* EINPROGRESS just happens to do the right thing. It 235 * actually means that the skb has been consumed and 236 * isn't coming back. 237 */ 238 return err ?: -EINPROGRESS; 239 } 240 #else 241 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 242 { 243 WARN_ON(1); 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 struct xfrm_offload *xo = xfrm_offload(skb); 353 354 len = skb->len + esp->tailen - skb_transport_offset(skb); 355 if (len + sizeof(struct iphdr) > IP_MAX_MTU) 356 return ERR_PTR(-EMSGSIZE); 357 358 uh = (struct udphdr *)esp->esph; 359 uh->source = sport; 360 uh->dest = dport; 361 uh->len = htons(len); 362 uh->check = 0; 363 364 /* For IPv4 ESP with UDP encapsulation, if xo is not null, the skb is in the crypto offload 365 * data path, which means that esp_output_udp_encap is called outside of the XFRM stack. 366 * In this case, the mac header doesn't point to the IPv4 protocol field, so don't set it. 367 */ 368 if (!xo || encap_type != UDP_ENCAP_ESPINUDP) 369 *skb_mac_header(skb) = IPPROTO_UDP; 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 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, skb); 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 ret = pskb_trim(skb, skb->len - trimlen); 735 if (unlikely(ret)) 736 return ret; 737 738 ret = nexthdr[1]; 739 740 out: 741 return ret; 742 } 743 744 int esp_input_done2(struct sk_buff *skb, int err) 745 { 746 const struct iphdr *iph; 747 struct xfrm_state *x = xfrm_input_state(skb); 748 struct xfrm_offload *xo = xfrm_offload(skb); 749 struct crypto_aead *aead = x->data; 750 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 751 int ihl; 752 753 if (!xo || !(xo->flags & CRYPTO_DONE)) 754 kfree(ESP_SKB_CB(skb)->tmp); 755 756 if (unlikely(err)) 757 goto out; 758 759 err = esp_remove_trailer(skb); 760 if (unlikely(err < 0)) 761 goto out; 762 763 iph = ip_hdr(skb); 764 ihl = iph->ihl * 4; 765 766 if (x->encap) { 767 struct xfrm_encap_tmpl *encap = x->encap; 768 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl); 769 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 770 __be16 source; 771 772 switch (x->encap->encap_type) { 773 case TCP_ENCAP_ESPINTCP: 774 source = th->source; 775 break; 776 case UDP_ENCAP_ESPINUDP: 777 source = uh->source; 778 break; 779 default: 780 WARN_ON_ONCE(1); 781 err = -EINVAL; 782 goto out; 783 } 784 785 /* 786 * 1) if the NAT-T peer's IP or port changed then 787 * advertise the change to the keying daemon. 788 * This is an inbound SA, so just compare 789 * SRC ports. 790 */ 791 if (iph->saddr != x->props.saddr.a4 || 792 source != encap->encap_sport) { 793 xfrm_address_t ipaddr; 794 795 ipaddr.a4 = iph->saddr; 796 km_new_mapping(x, &ipaddr, source); 797 798 /* XXX: perhaps add an extra 799 * policy check here, to see 800 * if we should allow or 801 * reject a packet from a 802 * different source 803 * address/port. 804 */ 805 } 806 807 /* 808 * 2) ignore UDP/TCP checksums in case 809 * of NAT-T in Transport Mode, or 810 * perform other post-processing fixes 811 * as per draft-ietf-ipsec-udp-encaps-06, 812 * section 3.1.2 813 */ 814 if (x->props.mode == XFRM_MODE_TRANSPORT) 815 skb->ip_summed = CHECKSUM_UNNECESSARY; 816 } 817 818 skb_pull_rcsum(skb, hlen); 819 if (x->props.mode == XFRM_MODE_TUNNEL) 820 skb_reset_transport_header(skb); 821 else 822 skb_set_transport_header(skb, -ihl); 823 824 /* RFC4303: Drop dummy packets without any error */ 825 if (err == IPPROTO_NONE) 826 err = -EINVAL; 827 828 out: 829 return err; 830 } 831 EXPORT_SYMBOL_GPL(esp_input_done2); 832 833 static void esp_input_done(void *data, int err) 834 { 835 struct sk_buff *skb = data; 836 837 xfrm_input_resume(skb, esp_input_done2(skb, err)); 838 } 839 840 static void esp_input_restore_header(struct sk_buff *skb) 841 { 842 esp_restore_header(skb, 0); 843 __skb_pull(skb, 4); 844 } 845 846 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 847 { 848 struct xfrm_state *x = xfrm_input_state(skb); 849 struct ip_esp_hdr *esph; 850 851 /* For ESN we move the header forward by 4 bytes to 852 * accommodate the high bits. We will move it back after 853 * decryption. 854 */ 855 if ((x->props.flags & XFRM_STATE_ESN)) { 856 esph = skb_push(skb, 4); 857 *seqhi = esph->spi; 858 esph->spi = esph->seq_no; 859 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 860 } 861 } 862 863 static void esp_input_done_esn(void *data, int err) 864 { 865 struct sk_buff *skb = data; 866 867 esp_input_restore_header(skb); 868 esp_input_done(data, err); 869 } 870 871 /* 872 * Note: detecting truncated vs. non-truncated authentication data is very 873 * expensive, so we only support truncated data, which is the recommended 874 * and common case. 875 */ 876 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 877 { 878 struct crypto_aead *aead = x->data; 879 struct aead_request *req; 880 struct sk_buff *trailer; 881 int ivlen = crypto_aead_ivsize(aead); 882 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 883 int nfrags; 884 int assoclen; 885 int seqhilen; 886 __be32 *seqhi; 887 void *tmp; 888 u8 *iv; 889 struct scatterlist *sg; 890 int err = -EINVAL; 891 892 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) 893 goto out; 894 895 if (elen <= 0) 896 goto out; 897 898 assoclen = sizeof(struct ip_esp_hdr); 899 seqhilen = 0; 900 901 if (x->props.flags & XFRM_STATE_ESN) { 902 seqhilen += sizeof(__be32); 903 assoclen += seqhilen; 904 } 905 906 if (!skb_cloned(skb)) { 907 if (!skb_is_nonlinear(skb)) { 908 nfrags = 1; 909 910 goto skip_cow; 911 } else if (!skb_has_frag_list(skb)) { 912 nfrags = skb_shinfo(skb)->nr_frags; 913 nfrags++; 914 915 goto skip_cow; 916 } 917 } 918 919 err = skb_cow_data(skb, 0, &trailer); 920 if (err < 0) 921 goto out; 922 923 nfrags = err; 924 925 skip_cow: 926 err = -ENOMEM; 927 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 928 if (!tmp) 929 goto out; 930 931 ESP_SKB_CB(skb)->tmp = tmp; 932 seqhi = esp_tmp_extra(tmp); 933 iv = esp_tmp_iv(aead, tmp, seqhilen); 934 req = esp_tmp_req(aead, iv); 935 sg = esp_req_sg(aead, req); 936 937 esp_input_set_header(skb, seqhi); 938 939 sg_init_table(sg, nfrags); 940 err = skb_to_sgvec(skb, sg, 0, skb->len); 941 if (unlikely(err < 0)) { 942 kfree(tmp); 943 goto out; 944 } 945 946 skb->ip_summed = CHECKSUM_NONE; 947 948 if ((x->props.flags & XFRM_STATE_ESN)) 949 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 950 else 951 aead_request_set_callback(req, 0, esp_input_done, skb); 952 953 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 954 aead_request_set_ad(req, assoclen); 955 956 err = crypto_aead_decrypt(req); 957 if (err == -EINPROGRESS) 958 goto out; 959 960 if ((x->props.flags & XFRM_STATE_ESN)) 961 esp_input_restore_header(skb); 962 963 err = esp_input_done2(skb, err); 964 965 out: 966 return err; 967 } 968 969 static int esp4_err(struct sk_buff *skb, u32 info) 970 { 971 struct net *net = dev_net(skb->dev); 972 const struct iphdr *iph = (const struct iphdr *)skb->data; 973 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 974 struct xfrm_state *x; 975 976 switch (icmp_hdr(skb)->type) { 977 case ICMP_DEST_UNREACH: 978 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 979 return 0; 980 break; 981 case ICMP_REDIRECT: 982 break; 983 default: 984 return 0; 985 } 986 987 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 988 esph->spi, IPPROTO_ESP, AF_INET); 989 if (!x) 990 return 0; 991 992 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 993 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP); 994 else 995 ipv4_redirect(skb, net, 0, IPPROTO_ESP); 996 xfrm_state_put(x); 997 998 return 0; 999 } 1000 1001 static void esp_destroy(struct xfrm_state *x) 1002 { 1003 struct crypto_aead *aead = x->data; 1004 1005 if (!aead) 1006 return; 1007 1008 crypto_free_aead(aead); 1009 } 1010 1011 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 1012 { 1013 char aead_name[CRYPTO_MAX_ALG_NAME]; 1014 struct crypto_aead *aead; 1015 int err; 1016 1017 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1018 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 1019 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1020 return -ENAMETOOLONG; 1021 } 1022 1023 aead = crypto_alloc_aead(aead_name, 0, 0); 1024 err = PTR_ERR(aead); 1025 if (IS_ERR(aead)) 1026 goto error; 1027 1028 x->data = aead; 1029 1030 err = crypto_aead_setkey(aead, x->aead->alg_key, 1031 (x->aead->alg_key_len + 7) / 8); 1032 if (err) 1033 goto error; 1034 1035 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1036 if (err) 1037 goto error; 1038 1039 return 0; 1040 1041 error: 1042 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1043 return err; 1044 } 1045 1046 static int esp_init_authenc(struct xfrm_state *x, 1047 struct netlink_ext_ack *extack) 1048 { 1049 struct crypto_aead *aead; 1050 struct crypto_authenc_key_param *param; 1051 struct rtattr *rta; 1052 char *key; 1053 char *p; 1054 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1055 unsigned int keylen; 1056 int err; 1057 1058 err = -ENAMETOOLONG; 1059 1060 if ((x->props.flags & XFRM_STATE_ESN)) { 1061 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1062 "%s%sauthencesn(%s,%s)%s", 1063 x->geniv ?: "", x->geniv ? "(" : "", 1064 x->aalg ? x->aalg->alg_name : "digest_null", 1065 x->ealg->alg_name, 1066 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1067 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1068 goto error; 1069 } 1070 } else { 1071 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1072 "%s%sauthenc(%s,%s)%s", 1073 x->geniv ?: "", x->geniv ? "(" : "", 1074 x->aalg ? x->aalg->alg_name : "digest_null", 1075 x->ealg->alg_name, 1076 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1077 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1078 goto error; 1079 } 1080 } 1081 1082 aead = crypto_alloc_aead(authenc_name, 0, 0); 1083 err = PTR_ERR(aead); 1084 if (IS_ERR(aead)) { 1085 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1086 goto error; 1087 } 1088 1089 x->data = aead; 1090 1091 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1092 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1093 err = -ENOMEM; 1094 key = kmalloc(keylen, GFP_KERNEL); 1095 if (!key) 1096 goto error; 1097 1098 p = key; 1099 rta = (void *)p; 1100 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1101 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1102 param = RTA_DATA(rta); 1103 p += RTA_SPACE(sizeof(*param)); 1104 1105 if (x->aalg) { 1106 struct xfrm_algo_desc *aalg_desc; 1107 1108 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1109 p += (x->aalg->alg_key_len + 7) / 8; 1110 1111 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1112 BUG_ON(!aalg_desc); 1113 1114 err = -EINVAL; 1115 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1116 crypto_aead_authsize(aead)) { 1117 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1118 goto free_key; 1119 } 1120 1121 err = crypto_aead_setauthsize( 1122 aead, x->aalg->alg_trunc_len / 8); 1123 if (err) { 1124 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1125 goto free_key; 1126 } 1127 } 1128 1129 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1130 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1131 1132 err = crypto_aead_setkey(aead, key, keylen); 1133 1134 free_key: 1135 kfree_sensitive(key); 1136 1137 error: 1138 return err; 1139 } 1140 1141 static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1142 { 1143 struct crypto_aead *aead; 1144 u32 align; 1145 int err; 1146 1147 x->data = NULL; 1148 1149 if (x->aead) { 1150 err = esp_init_aead(x, extack); 1151 } else if (x->ealg) { 1152 err = esp_init_authenc(x, extack); 1153 } else { 1154 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1155 err = -EINVAL; 1156 } 1157 1158 if (err) 1159 goto error; 1160 1161 aead = x->data; 1162 1163 x->props.header_len = sizeof(struct ip_esp_hdr) + 1164 crypto_aead_ivsize(aead); 1165 if (x->props.mode == XFRM_MODE_TUNNEL) 1166 x->props.header_len += sizeof(struct iphdr); 1167 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 1168 x->props.header_len += IPV4_BEET_PHMAXLEN; 1169 if (x->encap) { 1170 struct xfrm_encap_tmpl *encap = x->encap; 1171 1172 switch (encap->encap_type) { 1173 default: 1174 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1175 err = -EINVAL; 1176 goto error; 1177 case UDP_ENCAP_ESPINUDP: 1178 x->props.header_len += sizeof(struct udphdr); 1179 break; 1180 #ifdef CONFIG_INET_ESPINTCP 1181 case TCP_ENCAP_ESPINTCP: 1182 /* only the length field, TCP encap is done by 1183 * the socket 1184 */ 1185 x->props.header_len += 2; 1186 break; 1187 #endif 1188 } 1189 } 1190 1191 align = ALIGN(crypto_aead_blocksize(aead), 4); 1192 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1193 1194 error: 1195 return err; 1196 } 1197 1198 static int esp4_rcv_cb(struct sk_buff *skb, int err) 1199 { 1200 return 0; 1201 } 1202 1203 static const struct xfrm_type esp_type = 1204 { 1205 .owner = THIS_MODULE, 1206 .proto = IPPROTO_ESP, 1207 .flags = XFRM_TYPE_REPLAY_PROT, 1208 .init_state = esp_init_state, 1209 .destructor = esp_destroy, 1210 .input = esp_input, 1211 .output = esp_output, 1212 }; 1213 1214 static struct xfrm4_protocol esp4_protocol = { 1215 .handler = xfrm4_rcv, 1216 .input_handler = xfrm_input, 1217 .cb_handler = esp4_rcv_cb, 1218 .err_handler = esp4_err, 1219 .priority = 0, 1220 }; 1221 1222 static int __init esp4_init(void) 1223 { 1224 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 1225 pr_info("%s: can't add xfrm type\n", __func__); 1226 return -EAGAIN; 1227 } 1228 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 1229 pr_info("%s: can't add protocol\n", __func__); 1230 xfrm_unregister_type(&esp_type, AF_INET); 1231 return -EAGAIN; 1232 } 1233 return 0; 1234 } 1235 1236 static void __exit esp4_fini(void) 1237 { 1238 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 1239 pr_info("%s: can't remove protocol\n", __func__); 1240 xfrm_unregister_type(&esp_type, AF_INET); 1241 } 1242 1243 module_init(esp4_init); 1244 module_exit(esp4_fini); 1245 MODULE_DESCRIPTION("IPv4 ESP transformation library"); 1246 MODULE_LICENSE("GPL"); 1247 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1248