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 __be32 *udpdata32; 352 unsigned int len; 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 *skb_mac_header(skb) = IPPROTO_UDP; 365 366 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) { 367 udpdata32 = (__be32 *)(uh + 1); 368 udpdata32[0] = udpdata32[1] = 0; 369 return (struct ip_esp_hdr *)(udpdata32 + 2); 370 } 371 372 return (struct ip_esp_hdr *)(uh + 1); 373 } 374 375 #ifdef CONFIG_INET_ESPINTCP 376 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 377 struct sk_buff *skb, 378 struct esp_info *esp) 379 { 380 __be16 *lenp = (void *)esp->esph; 381 struct ip_esp_hdr *esph; 382 unsigned int len; 383 struct sock *sk; 384 385 len = skb->len + esp->tailen - skb_transport_offset(skb); 386 if (len > IP_MAX_MTU) 387 return ERR_PTR(-EMSGSIZE); 388 389 rcu_read_lock(); 390 sk = esp_find_tcp_sk(x); 391 rcu_read_unlock(); 392 393 if (IS_ERR(sk)) 394 return ERR_CAST(sk); 395 396 *lenp = htons(len); 397 esph = (struct ip_esp_hdr *)(lenp + 1); 398 399 return esph; 400 } 401 #else 402 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 403 struct sk_buff *skb, 404 struct esp_info *esp) 405 { 406 return ERR_PTR(-EOPNOTSUPP); 407 } 408 #endif 409 410 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb, 411 struct esp_info *esp) 412 { 413 struct xfrm_encap_tmpl *encap = x->encap; 414 struct ip_esp_hdr *esph; 415 __be16 sport, dport; 416 int encap_type; 417 418 spin_lock_bh(&x->lock); 419 sport = encap->encap_sport; 420 dport = encap->encap_dport; 421 encap_type = encap->encap_type; 422 spin_unlock_bh(&x->lock); 423 424 switch (encap_type) { 425 default: 426 case UDP_ENCAP_ESPINUDP: 427 case UDP_ENCAP_ESPINUDP_NON_IKE: 428 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport); 429 break; 430 case TCP_ENCAP_ESPINTCP: 431 esph = esp_output_tcp_encap(x, skb, esp); 432 break; 433 } 434 435 if (IS_ERR(esph)) 436 return PTR_ERR(esph); 437 438 esp->esph = esph; 439 440 return 0; 441 } 442 443 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 444 { 445 u8 *tail; 446 int nfrags; 447 int esph_offset; 448 struct page *page; 449 struct sk_buff *trailer; 450 int tailen = esp->tailen; 451 452 /* this is non-NULL only with TCP/UDP Encapsulation */ 453 if (x->encap) { 454 int err = esp_output_encap(x, skb, esp); 455 456 if (err < 0) 457 return err; 458 } 459 460 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE || 461 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE) 462 goto cow; 463 464 if (!skb_cloned(skb)) { 465 if (tailen <= skb_tailroom(skb)) { 466 nfrags = 1; 467 trailer = skb; 468 tail = skb_tail_pointer(trailer); 469 470 goto skip_cow; 471 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 472 && !skb_has_frag_list(skb)) { 473 int allocsize; 474 struct sock *sk = skb->sk; 475 struct page_frag *pfrag = &x->xfrag; 476 477 esp->inplace = false; 478 479 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 480 481 spin_lock_bh(&x->lock); 482 483 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 484 spin_unlock_bh(&x->lock); 485 goto cow; 486 } 487 488 page = pfrag->page; 489 get_page(page); 490 491 tail = page_address(page) + pfrag->offset; 492 493 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 494 495 nfrags = skb_shinfo(skb)->nr_frags; 496 497 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 498 tailen); 499 skb_shinfo(skb)->nr_frags = ++nfrags; 500 501 pfrag->offset = pfrag->offset + allocsize; 502 503 spin_unlock_bh(&x->lock); 504 505 nfrags++; 506 507 skb_len_add(skb, tailen); 508 if (sk && sk_fullsock(sk)) 509 refcount_add(tailen, &sk->sk_wmem_alloc); 510 511 goto out; 512 } 513 } 514 515 cow: 516 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 517 518 nfrags = skb_cow_data(skb, tailen, &trailer); 519 if (nfrags < 0) 520 goto out; 521 tail = skb_tail_pointer(trailer); 522 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 523 524 skip_cow: 525 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 526 pskb_put(skb, trailer, tailen); 527 528 out: 529 return nfrags; 530 } 531 EXPORT_SYMBOL_GPL(esp_output_head); 532 533 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 534 { 535 u8 *iv; 536 int alen; 537 void *tmp; 538 int ivlen; 539 int assoclen; 540 int extralen; 541 struct page *page; 542 struct ip_esp_hdr *esph; 543 struct crypto_aead *aead; 544 struct aead_request *req; 545 struct scatterlist *sg, *dsg; 546 struct esp_output_extra *extra; 547 int err = -ENOMEM; 548 549 assoclen = sizeof(struct ip_esp_hdr); 550 extralen = 0; 551 552 if (x->props.flags & XFRM_STATE_ESN) { 553 extralen += sizeof(*extra); 554 assoclen += sizeof(__be32); 555 } 556 557 aead = x->data; 558 alen = crypto_aead_authsize(aead); 559 ivlen = crypto_aead_ivsize(aead); 560 561 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 562 if (!tmp) 563 goto error; 564 565 extra = esp_tmp_extra(tmp); 566 iv = esp_tmp_iv(aead, tmp, extralen); 567 req = esp_tmp_req(aead, iv); 568 sg = esp_req_sg(aead, req); 569 570 if (esp->inplace) 571 dsg = sg; 572 else 573 dsg = &sg[esp->nfrags]; 574 575 esph = esp_output_set_extra(skb, x, esp->esph, extra); 576 esp->esph = esph; 577 578 sg_init_table(sg, esp->nfrags); 579 err = skb_to_sgvec(skb, sg, 580 (unsigned char *)esph - skb->data, 581 assoclen + ivlen + esp->clen + alen); 582 if (unlikely(err < 0)) 583 goto error_free; 584 585 if (!esp->inplace) { 586 int allocsize; 587 struct page_frag *pfrag = &x->xfrag; 588 589 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 590 591 spin_lock_bh(&x->lock); 592 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 593 spin_unlock_bh(&x->lock); 594 goto error_free; 595 } 596 597 skb_shinfo(skb)->nr_frags = 1; 598 599 page = pfrag->page; 600 get_page(page); 601 /* replace page frags in skb with new page */ 602 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 603 pfrag->offset = pfrag->offset + allocsize; 604 spin_unlock_bh(&x->lock); 605 606 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 607 err = skb_to_sgvec(skb, dsg, 608 (unsigned char *)esph - skb->data, 609 assoclen + ivlen + esp->clen + alen); 610 if (unlikely(err < 0)) 611 goto error_free; 612 } 613 614 if ((x->props.flags & XFRM_STATE_ESN)) 615 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 616 else 617 aead_request_set_callback(req, 0, esp_output_done, skb); 618 619 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 620 aead_request_set_ad(req, assoclen); 621 622 memset(iv, 0, ivlen); 623 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 624 min(ivlen, 8)); 625 626 ESP_SKB_CB(skb)->tmp = tmp; 627 err = crypto_aead_encrypt(req); 628 629 switch (err) { 630 case -EINPROGRESS: 631 goto error; 632 633 case -ENOSPC: 634 err = NET_XMIT_DROP; 635 break; 636 637 case 0: 638 if ((x->props.flags & XFRM_STATE_ESN)) 639 esp_output_restore_header(skb); 640 } 641 642 if (sg != dsg) 643 esp_ssg_unref(x, tmp, skb); 644 645 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 646 err = esp_output_tail_tcp(x, skb); 647 648 error_free: 649 kfree(tmp); 650 error: 651 return err; 652 } 653 EXPORT_SYMBOL_GPL(esp_output_tail); 654 655 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 656 { 657 int alen; 658 int blksize; 659 struct ip_esp_hdr *esph; 660 struct crypto_aead *aead; 661 struct esp_info esp; 662 663 esp.inplace = true; 664 665 esp.proto = *skb_mac_header(skb); 666 *skb_mac_header(skb) = IPPROTO_ESP; 667 668 /* skb is pure payload to encrypt */ 669 670 aead = x->data; 671 alen = crypto_aead_authsize(aead); 672 673 esp.tfclen = 0; 674 if (x->tfcpad) { 675 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 676 u32 padto; 677 678 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 679 if (skb->len < padto) 680 esp.tfclen = padto - skb->len; 681 } 682 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 683 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 684 esp.plen = esp.clen - skb->len - esp.tfclen; 685 esp.tailen = esp.tfclen + esp.plen + alen; 686 687 esp.esph = ip_esp_hdr(skb); 688 689 esp.nfrags = esp_output_head(x, skb, &esp); 690 if (esp.nfrags < 0) 691 return esp.nfrags; 692 693 esph = esp.esph; 694 esph->spi = x->id.spi; 695 696 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 697 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 698 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 699 700 skb_push(skb, -skb_network_offset(skb)); 701 702 return esp_output_tail(x, skb, &esp); 703 } 704 705 static inline int esp_remove_trailer(struct sk_buff *skb) 706 { 707 struct xfrm_state *x = xfrm_input_state(skb); 708 struct crypto_aead *aead = x->data; 709 int alen, hlen, elen; 710 int padlen, trimlen; 711 __wsum csumdiff; 712 u8 nexthdr[2]; 713 int ret; 714 715 alen = crypto_aead_authsize(aead); 716 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 717 elen = skb->len - hlen; 718 719 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) 720 BUG(); 721 722 ret = -EINVAL; 723 padlen = nexthdr[0]; 724 if (padlen + 2 + alen >= elen) { 725 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 726 padlen + 2, elen - alen); 727 goto out; 728 } 729 730 trimlen = alen + padlen + 2; 731 if (skb->ip_summed == CHECKSUM_COMPLETE) { 732 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 733 skb->csum = csum_block_sub(skb->csum, csumdiff, 734 skb->len - trimlen); 735 } 736 ret = pskb_trim(skb, skb->len - trimlen); 737 if (unlikely(ret)) 738 return ret; 739 740 ret = nexthdr[1]; 741 742 out: 743 return ret; 744 } 745 746 int esp_input_done2(struct sk_buff *skb, int err) 747 { 748 const struct iphdr *iph; 749 struct xfrm_state *x = xfrm_input_state(skb); 750 struct xfrm_offload *xo = xfrm_offload(skb); 751 struct crypto_aead *aead = x->data; 752 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 753 int ihl; 754 755 if (!xo || !(xo->flags & CRYPTO_DONE)) 756 kfree(ESP_SKB_CB(skb)->tmp); 757 758 if (unlikely(err)) 759 goto out; 760 761 err = esp_remove_trailer(skb); 762 if (unlikely(err < 0)) 763 goto out; 764 765 iph = ip_hdr(skb); 766 ihl = iph->ihl * 4; 767 768 if (x->encap) { 769 struct xfrm_encap_tmpl *encap = x->encap; 770 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl); 771 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 772 __be16 source; 773 774 switch (x->encap->encap_type) { 775 case TCP_ENCAP_ESPINTCP: 776 source = th->source; 777 break; 778 case UDP_ENCAP_ESPINUDP: 779 case UDP_ENCAP_ESPINUDP_NON_IKE: 780 source = uh->source; 781 break; 782 default: 783 WARN_ON_ONCE(1); 784 err = -EINVAL; 785 goto out; 786 } 787 788 /* 789 * 1) if the NAT-T peer's IP or port changed then 790 * advertise the change to the keying daemon. 791 * This is an inbound SA, so just compare 792 * SRC ports. 793 */ 794 if (iph->saddr != x->props.saddr.a4 || 795 source != encap->encap_sport) { 796 xfrm_address_t ipaddr; 797 798 ipaddr.a4 = iph->saddr; 799 km_new_mapping(x, &ipaddr, source); 800 801 /* XXX: perhaps add an extra 802 * policy check here, to see 803 * if we should allow or 804 * reject a packet from a 805 * different source 806 * address/port. 807 */ 808 } 809 810 /* 811 * 2) ignore UDP/TCP checksums in case 812 * of NAT-T in Transport Mode, or 813 * perform other post-processing fixes 814 * as per draft-ietf-ipsec-udp-encaps-06, 815 * section 3.1.2 816 */ 817 if (x->props.mode == XFRM_MODE_TRANSPORT) 818 skb->ip_summed = CHECKSUM_UNNECESSARY; 819 } 820 821 skb_pull_rcsum(skb, hlen); 822 if (x->props.mode == XFRM_MODE_TUNNEL) 823 skb_reset_transport_header(skb); 824 else 825 skb_set_transport_header(skb, -ihl); 826 827 /* RFC4303: Drop dummy packets without any error */ 828 if (err == IPPROTO_NONE) 829 err = -EINVAL; 830 831 out: 832 return err; 833 } 834 EXPORT_SYMBOL_GPL(esp_input_done2); 835 836 static void esp_input_done(void *data, int err) 837 { 838 struct sk_buff *skb = data; 839 840 xfrm_input_resume(skb, esp_input_done2(skb, err)); 841 } 842 843 static void esp_input_restore_header(struct sk_buff *skb) 844 { 845 esp_restore_header(skb, 0); 846 __skb_pull(skb, 4); 847 } 848 849 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 850 { 851 struct xfrm_state *x = xfrm_input_state(skb); 852 struct ip_esp_hdr *esph; 853 854 /* For ESN we move the header forward by 4 bytes to 855 * accommodate the high bits. We will move it back after 856 * decryption. 857 */ 858 if ((x->props.flags & XFRM_STATE_ESN)) { 859 esph = skb_push(skb, 4); 860 *seqhi = esph->spi; 861 esph->spi = esph->seq_no; 862 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 863 } 864 } 865 866 static void esp_input_done_esn(void *data, int err) 867 { 868 struct sk_buff *skb = data; 869 870 esp_input_restore_header(skb); 871 esp_input_done(data, err); 872 } 873 874 /* 875 * Note: detecting truncated vs. non-truncated authentication data is very 876 * expensive, so we only support truncated data, which is the recommended 877 * and common case. 878 */ 879 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 880 { 881 struct crypto_aead *aead = x->data; 882 struct aead_request *req; 883 struct sk_buff *trailer; 884 int ivlen = crypto_aead_ivsize(aead); 885 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 886 int nfrags; 887 int assoclen; 888 int seqhilen; 889 __be32 *seqhi; 890 void *tmp; 891 u8 *iv; 892 struct scatterlist *sg; 893 int err = -EINVAL; 894 895 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) 896 goto out; 897 898 if (elen <= 0) 899 goto out; 900 901 assoclen = sizeof(struct ip_esp_hdr); 902 seqhilen = 0; 903 904 if (x->props.flags & XFRM_STATE_ESN) { 905 seqhilen += sizeof(__be32); 906 assoclen += seqhilen; 907 } 908 909 if (!skb_cloned(skb)) { 910 if (!skb_is_nonlinear(skb)) { 911 nfrags = 1; 912 913 goto skip_cow; 914 } else if (!skb_has_frag_list(skb)) { 915 nfrags = skb_shinfo(skb)->nr_frags; 916 nfrags++; 917 918 goto skip_cow; 919 } 920 } 921 922 err = skb_cow_data(skb, 0, &trailer); 923 if (err < 0) 924 goto out; 925 926 nfrags = err; 927 928 skip_cow: 929 err = -ENOMEM; 930 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 931 if (!tmp) 932 goto out; 933 934 ESP_SKB_CB(skb)->tmp = tmp; 935 seqhi = esp_tmp_extra(tmp); 936 iv = esp_tmp_iv(aead, tmp, seqhilen); 937 req = esp_tmp_req(aead, iv); 938 sg = esp_req_sg(aead, req); 939 940 esp_input_set_header(skb, seqhi); 941 942 sg_init_table(sg, nfrags); 943 err = skb_to_sgvec(skb, sg, 0, skb->len); 944 if (unlikely(err < 0)) { 945 kfree(tmp); 946 goto out; 947 } 948 949 skb->ip_summed = CHECKSUM_NONE; 950 951 if ((x->props.flags & XFRM_STATE_ESN)) 952 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 953 else 954 aead_request_set_callback(req, 0, esp_input_done, skb); 955 956 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 957 aead_request_set_ad(req, assoclen); 958 959 err = crypto_aead_decrypt(req); 960 if (err == -EINPROGRESS) 961 goto out; 962 963 if ((x->props.flags & XFRM_STATE_ESN)) 964 esp_input_restore_header(skb); 965 966 err = esp_input_done2(skb, err); 967 968 out: 969 return err; 970 } 971 972 static int esp4_err(struct sk_buff *skb, u32 info) 973 { 974 struct net *net = dev_net(skb->dev); 975 const struct iphdr *iph = (const struct iphdr *)skb->data; 976 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 977 struct xfrm_state *x; 978 979 switch (icmp_hdr(skb)->type) { 980 case ICMP_DEST_UNREACH: 981 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 982 return 0; 983 break; 984 case ICMP_REDIRECT: 985 break; 986 default: 987 return 0; 988 } 989 990 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 991 esph->spi, IPPROTO_ESP, AF_INET); 992 if (!x) 993 return 0; 994 995 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 996 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP); 997 else 998 ipv4_redirect(skb, net, 0, IPPROTO_ESP); 999 xfrm_state_put(x); 1000 1001 return 0; 1002 } 1003 1004 static void esp_destroy(struct xfrm_state *x) 1005 { 1006 struct crypto_aead *aead = x->data; 1007 1008 if (!aead) 1009 return; 1010 1011 crypto_free_aead(aead); 1012 } 1013 1014 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 1015 { 1016 char aead_name[CRYPTO_MAX_ALG_NAME]; 1017 struct crypto_aead *aead; 1018 int err; 1019 1020 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1021 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 1022 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1023 return -ENAMETOOLONG; 1024 } 1025 1026 aead = crypto_alloc_aead(aead_name, 0, 0); 1027 err = PTR_ERR(aead); 1028 if (IS_ERR(aead)) 1029 goto error; 1030 1031 x->data = aead; 1032 1033 err = crypto_aead_setkey(aead, x->aead->alg_key, 1034 (x->aead->alg_key_len + 7) / 8); 1035 if (err) 1036 goto error; 1037 1038 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1039 if (err) 1040 goto error; 1041 1042 return 0; 1043 1044 error: 1045 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1046 return err; 1047 } 1048 1049 static int esp_init_authenc(struct xfrm_state *x, 1050 struct netlink_ext_ack *extack) 1051 { 1052 struct crypto_aead *aead; 1053 struct crypto_authenc_key_param *param; 1054 struct rtattr *rta; 1055 char *key; 1056 char *p; 1057 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1058 unsigned int keylen; 1059 int err; 1060 1061 err = -ENAMETOOLONG; 1062 1063 if ((x->props.flags & XFRM_STATE_ESN)) { 1064 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1065 "%s%sauthencesn(%s,%s)%s", 1066 x->geniv ?: "", x->geniv ? "(" : "", 1067 x->aalg ? x->aalg->alg_name : "digest_null", 1068 x->ealg->alg_name, 1069 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1070 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1071 goto error; 1072 } 1073 } else { 1074 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1075 "%s%sauthenc(%s,%s)%s", 1076 x->geniv ?: "", x->geniv ? "(" : "", 1077 x->aalg ? x->aalg->alg_name : "digest_null", 1078 x->ealg->alg_name, 1079 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1080 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1081 goto error; 1082 } 1083 } 1084 1085 aead = crypto_alloc_aead(authenc_name, 0, 0); 1086 err = PTR_ERR(aead); 1087 if (IS_ERR(aead)) { 1088 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1089 goto error; 1090 } 1091 1092 x->data = aead; 1093 1094 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1095 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1096 err = -ENOMEM; 1097 key = kmalloc(keylen, GFP_KERNEL); 1098 if (!key) 1099 goto error; 1100 1101 p = key; 1102 rta = (void *)p; 1103 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1104 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1105 param = RTA_DATA(rta); 1106 p += RTA_SPACE(sizeof(*param)); 1107 1108 if (x->aalg) { 1109 struct xfrm_algo_desc *aalg_desc; 1110 1111 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1112 p += (x->aalg->alg_key_len + 7) / 8; 1113 1114 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1115 BUG_ON(!aalg_desc); 1116 1117 err = -EINVAL; 1118 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1119 crypto_aead_authsize(aead)) { 1120 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1121 goto free_key; 1122 } 1123 1124 err = crypto_aead_setauthsize( 1125 aead, x->aalg->alg_trunc_len / 8); 1126 if (err) { 1127 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1128 goto free_key; 1129 } 1130 } 1131 1132 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1133 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1134 1135 err = crypto_aead_setkey(aead, key, keylen); 1136 1137 free_key: 1138 kfree_sensitive(key); 1139 1140 error: 1141 return err; 1142 } 1143 1144 static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1145 { 1146 struct crypto_aead *aead; 1147 u32 align; 1148 int err; 1149 1150 x->data = NULL; 1151 1152 if (x->aead) { 1153 err = esp_init_aead(x, extack); 1154 } else if (x->ealg) { 1155 err = esp_init_authenc(x, extack); 1156 } else { 1157 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1158 err = -EINVAL; 1159 } 1160 1161 if (err) 1162 goto error; 1163 1164 aead = x->data; 1165 1166 x->props.header_len = sizeof(struct ip_esp_hdr) + 1167 crypto_aead_ivsize(aead); 1168 if (x->props.mode == XFRM_MODE_TUNNEL) 1169 x->props.header_len += sizeof(struct iphdr); 1170 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 1171 x->props.header_len += IPV4_BEET_PHMAXLEN; 1172 if (x->encap) { 1173 struct xfrm_encap_tmpl *encap = x->encap; 1174 1175 switch (encap->encap_type) { 1176 default: 1177 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1178 err = -EINVAL; 1179 goto error; 1180 case UDP_ENCAP_ESPINUDP: 1181 x->props.header_len += sizeof(struct udphdr); 1182 break; 1183 case UDP_ENCAP_ESPINUDP_NON_IKE: 1184 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 1185 break; 1186 #ifdef CONFIG_INET_ESPINTCP 1187 case TCP_ENCAP_ESPINTCP: 1188 /* only the length field, TCP encap is done by 1189 * the socket 1190 */ 1191 x->props.header_len += 2; 1192 break; 1193 #endif 1194 } 1195 } 1196 1197 align = ALIGN(crypto_aead_blocksize(aead), 4); 1198 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1199 1200 error: 1201 return err; 1202 } 1203 1204 static int esp4_rcv_cb(struct sk_buff *skb, int err) 1205 { 1206 return 0; 1207 } 1208 1209 static const struct xfrm_type esp_type = 1210 { 1211 .owner = THIS_MODULE, 1212 .proto = IPPROTO_ESP, 1213 .flags = XFRM_TYPE_REPLAY_PROT, 1214 .init_state = esp_init_state, 1215 .destructor = esp_destroy, 1216 .input = esp_input, 1217 .output = esp_output, 1218 }; 1219 1220 static struct xfrm4_protocol esp4_protocol = { 1221 .handler = xfrm4_rcv, 1222 .input_handler = xfrm_input, 1223 .cb_handler = esp4_rcv_cb, 1224 .err_handler = esp4_err, 1225 .priority = 0, 1226 }; 1227 1228 static int __init esp4_init(void) 1229 { 1230 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 1231 pr_info("%s: can't add xfrm type\n", __func__); 1232 return -EAGAIN; 1233 } 1234 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 1235 pr_info("%s: can't add protocol\n", __func__); 1236 xfrm_unregister_type(&esp_type, AF_INET); 1237 return -EAGAIN; 1238 } 1239 return 0; 1240 } 1241 1242 static void __exit esp4_fini(void) 1243 { 1244 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 1245 pr_info("%s: can't remove protocol\n", __func__); 1246 xfrm_unregister_type(&esp_type, AF_INET); 1247 } 1248 1249 module_init(esp4_init); 1250 module_exit(esp4_fini); 1251 MODULE_DESCRIPTION("IPv4 ESP transformation library"); 1252 MODULE_LICENSE("GPL"); 1253 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1254