1 // SPDX-License-Identifier: GPL-2.0-only 2 #define pr_fmt(fmt) "IPsec: " fmt 3 4 #include <crypto/aead.h> 5 #include <crypto/authenc.h> 6 #include <linux/err.h> 7 #include <linux/module.h> 8 #include <net/ip.h> 9 #include <net/xfrm.h> 10 #include <net/esp.h> 11 #include <linux/scatterlist.h> 12 #include <linux/kernel.h> 13 #include <linux/pfkeyv2.h> 14 #include <linux/rtnetlink.h> 15 #include <linux/slab.h> 16 #include <linux/spinlock.h> 17 #include <linux/in6.h> 18 #include <net/icmp.h> 19 #include <net/protocol.h> 20 #include <net/udp.h> 21 #include <net/tcp.h> 22 #include <net/espintcp.h> 23 24 #include <linux/highmem.h> 25 26 struct esp_skb_cb { 27 struct xfrm_skb_cb xfrm; 28 void *tmp; 29 }; 30 31 struct esp_output_extra { 32 __be32 seqhi; 33 u32 esphoff; 34 }; 35 36 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0])) 37 38 /* 39 * Allocate an AEAD request structure with extra space for SG and IV. 40 * 41 * For alignment considerations the IV is placed at the front, followed 42 * by the request and finally the SG list. 43 * 44 * TODO: Use spare space in skb for this where possible. 45 */ 46 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen) 47 { 48 unsigned int len; 49 50 len = extralen; 51 52 len += crypto_aead_ivsize(aead); 53 54 if (len) { 55 len += crypto_aead_alignmask(aead) & 56 ~(crypto_tfm_ctx_alignment() - 1); 57 len = ALIGN(len, crypto_tfm_ctx_alignment()); 58 } 59 60 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead); 61 len = ALIGN(len, __alignof__(struct scatterlist)); 62 63 len += sizeof(struct scatterlist) * nfrags; 64 65 return kmalloc(len, GFP_ATOMIC); 66 } 67 68 static inline void *esp_tmp_extra(void *tmp) 69 { 70 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra)); 71 } 72 73 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen) 74 { 75 return crypto_aead_ivsize(aead) ? 76 PTR_ALIGN((u8 *)tmp + extralen, 77 crypto_aead_alignmask(aead) + 1) : tmp + extralen; 78 } 79 80 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv) 81 { 82 struct aead_request *req; 83 84 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead), 85 crypto_tfm_ctx_alignment()); 86 aead_request_set_tfm(req, aead); 87 return req; 88 } 89 90 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead, 91 struct aead_request *req) 92 { 93 return (void *)ALIGN((unsigned long)(req + 1) + 94 crypto_aead_reqsize(aead), 95 __alignof__(struct scatterlist)); 96 } 97 98 static void esp_ssg_unref(struct xfrm_state *x, void *tmp) 99 { 100 struct esp_output_extra *extra = esp_tmp_extra(tmp); 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(*extra); 109 110 extra = esp_tmp_extra(tmp); 111 iv = esp_tmp_iv(aead, tmp, extralen); 112 req = esp_tmp_req(aead, iv); 113 114 /* Unref skb_frag_pages in the src scatterlist if necessary. 115 * Skip the first sg which comes from skb->data. 116 */ 117 if (req->src != req->dst) 118 for (sg = sg_next(req->src); sg; sg = sg_next(sg)) 119 put_page(sg_page(sg)); 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 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(xs_net(x), &tcp_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(struct crypto_async_request *base, int err) 249 { 250 struct sk_buff *skb = base->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); 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(struct crypto_async_request *base, int err) 337 { 338 struct sk_buff *skb = base->data; 339 340 esp_output_restore_header(skb); 341 esp_output_done(base, 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 (!skb_cloned(skb)) { 461 if (tailen <= skb_tailroom(skb)) { 462 nfrags = 1; 463 trailer = skb; 464 tail = skb_tail_pointer(trailer); 465 466 goto skip_cow; 467 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 468 && !skb_has_frag_list(skb)) { 469 int allocsize; 470 struct sock *sk = skb->sk; 471 struct page_frag *pfrag = &x->xfrag; 472 473 esp->inplace = false; 474 475 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 476 477 spin_lock_bh(&x->lock); 478 479 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 480 spin_unlock_bh(&x->lock); 481 goto cow; 482 } 483 484 page = pfrag->page; 485 get_page(page); 486 487 tail = page_address(page) + pfrag->offset; 488 489 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 490 491 nfrags = skb_shinfo(skb)->nr_frags; 492 493 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 494 tailen); 495 skb_shinfo(skb)->nr_frags = ++nfrags; 496 497 pfrag->offset = pfrag->offset + allocsize; 498 499 spin_unlock_bh(&x->lock); 500 501 nfrags++; 502 503 skb->len += tailen; 504 skb->data_len += tailen; 505 skb->truesize += tailen; 506 if (sk && sk_fullsock(sk)) 507 refcount_add(tailen, &sk->sk_wmem_alloc); 508 509 goto out; 510 } 511 } 512 513 cow: 514 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 515 516 nfrags = skb_cow_data(skb, tailen, &trailer); 517 if (nfrags < 0) 518 goto out; 519 tail = skb_tail_pointer(trailer); 520 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 521 522 skip_cow: 523 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 524 pskb_put(skb, trailer, tailen); 525 526 out: 527 return nfrags; 528 } 529 EXPORT_SYMBOL_GPL(esp_output_head); 530 531 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 532 { 533 u8 *iv; 534 int alen; 535 void *tmp; 536 int ivlen; 537 int assoclen; 538 int extralen; 539 struct page *page; 540 struct ip_esp_hdr *esph; 541 struct crypto_aead *aead; 542 struct aead_request *req; 543 struct scatterlist *sg, *dsg; 544 struct esp_output_extra *extra; 545 int err = -ENOMEM; 546 547 assoclen = sizeof(struct ip_esp_hdr); 548 extralen = 0; 549 550 if (x->props.flags & XFRM_STATE_ESN) { 551 extralen += sizeof(*extra); 552 assoclen += sizeof(__be32); 553 } 554 555 aead = x->data; 556 alen = crypto_aead_authsize(aead); 557 ivlen = crypto_aead_ivsize(aead); 558 559 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 560 if (!tmp) 561 goto error; 562 563 extra = esp_tmp_extra(tmp); 564 iv = esp_tmp_iv(aead, tmp, extralen); 565 req = esp_tmp_req(aead, iv); 566 sg = esp_req_sg(aead, req); 567 568 if (esp->inplace) 569 dsg = sg; 570 else 571 dsg = &sg[esp->nfrags]; 572 573 esph = esp_output_set_extra(skb, x, esp->esph, extra); 574 esp->esph = esph; 575 576 sg_init_table(sg, esp->nfrags); 577 err = skb_to_sgvec(skb, sg, 578 (unsigned char *)esph - skb->data, 579 assoclen + ivlen + esp->clen + alen); 580 if (unlikely(err < 0)) 581 goto error_free; 582 583 if (!esp->inplace) { 584 int allocsize; 585 struct page_frag *pfrag = &x->xfrag; 586 587 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 588 589 spin_lock_bh(&x->lock); 590 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 591 spin_unlock_bh(&x->lock); 592 goto error_free; 593 } 594 595 skb_shinfo(skb)->nr_frags = 1; 596 597 page = pfrag->page; 598 get_page(page); 599 /* replace page frags in skb with new page */ 600 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 601 pfrag->offset = pfrag->offset + allocsize; 602 spin_unlock_bh(&x->lock); 603 604 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 605 err = skb_to_sgvec(skb, dsg, 606 (unsigned char *)esph - skb->data, 607 assoclen + ivlen + esp->clen + alen); 608 if (unlikely(err < 0)) 609 goto error_free; 610 } 611 612 if ((x->props.flags & XFRM_STATE_ESN)) 613 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 614 else 615 aead_request_set_callback(req, 0, esp_output_done, skb); 616 617 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 618 aead_request_set_ad(req, assoclen); 619 620 memset(iv, 0, ivlen); 621 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 622 min(ivlen, 8)); 623 624 ESP_SKB_CB(skb)->tmp = tmp; 625 err = crypto_aead_encrypt(req); 626 627 switch (err) { 628 case -EINPROGRESS: 629 goto error; 630 631 case -ENOSPC: 632 err = NET_XMIT_DROP; 633 break; 634 635 case 0: 636 if ((x->props.flags & XFRM_STATE_ESN)) 637 esp_output_restore_header(skb); 638 } 639 640 if (sg != dsg) 641 esp_ssg_unref(x, tmp); 642 643 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 644 err = esp_output_tail_tcp(x, skb); 645 646 error_free: 647 kfree(tmp); 648 error: 649 return err; 650 } 651 EXPORT_SYMBOL_GPL(esp_output_tail); 652 653 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 654 { 655 int alen; 656 int blksize; 657 struct ip_esp_hdr *esph; 658 struct crypto_aead *aead; 659 struct esp_info esp; 660 661 esp.inplace = true; 662 663 esp.proto = *skb_mac_header(skb); 664 *skb_mac_header(skb) = IPPROTO_ESP; 665 666 /* skb is pure payload to encrypt */ 667 668 aead = x->data; 669 alen = crypto_aead_authsize(aead); 670 671 esp.tfclen = 0; 672 if (x->tfcpad) { 673 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 674 u32 padto; 675 676 padto = min(x->tfcpad, __xfrm_state_mtu(x, dst->child_mtu_cached)); 677 if (skb->len < padto) 678 esp.tfclen = padto - skb->len; 679 } 680 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 681 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 682 esp.plen = esp.clen - skb->len - esp.tfclen; 683 esp.tailen = esp.tfclen + esp.plen + alen; 684 685 esp.esph = ip_esp_hdr(skb); 686 687 esp.nfrags = esp_output_head(x, skb, &esp); 688 if (esp.nfrags < 0) 689 return esp.nfrags; 690 691 esph = esp.esph; 692 esph->spi = x->id.spi; 693 694 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 695 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 696 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 697 698 skb_push(skb, -skb_network_offset(skb)); 699 700 return esp_output_tail(x, skb, &esp); 701 } 702 703 static inline int esp_remove_trailer(struct sk_buff *skb) 704 { 705 struct xfrm_state *x = xfrm_input_state(skb); 706 struct xfrm_offload *xo = xfrm_offload(skb); 707 struct crypto_aead *aead = x->data; 708 int alen, hlen, elen; 709 int padlen, trimlen; 710 __wsum csumdiff; 711 u8 nexthdr[2]; 712 int ret; 713 714 alen = crypto_aead_authsize(aead); 715 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 716 elen = skb->len - hlen; 717 718 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) { 719 ret = xo->proto; 720 goto out; 721 } 722 723 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) 724 BUG(); 725 726 ret = -EINVAL; 727 padlen = nexthdr[0]; 728 if (padlen + 2 + alen >= elen) { 729 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 730 padlen + 2, elen - alen); 731 goto out; 732 } 733 734 trimlen = alen + padlen + 2; 735 if (skb->ip_summed == CHECKSUM_COMPLETE) { 736 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 737 skb->csum = csum_block_sub(skb->csum, csumdiff, 738 skb->len - trimlen); 739 } 740 pskb_trim(skb, skb->len - trimlen); 741 742 ret = nexthdr[1]; 743 744 out: 745 return ret; 746 } 747 748 int esp_input_done2(struct sk_buff *skb, int err) 749 { 750 const struct iphdr *iph; 751 struct xfrm_state *x = xfrm_input_state(skb); 752 struct xfrm_offload *xo = xfrm_offload(skb); 753 struct crypto_aead *aead = x->data; 754 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 755 int ihl; 756 757 if (!xo || !(xo->flags & CRYPTO_DONE)) 758 kfree(ESP_SKB_CB(skb)->tmp); 759 760 if (unlikely(err)) 761 goto out; 762 763 err = esp_remove_trailer(skb); 764 if (unlikely(err < 0)) 765 goto out; 766 767 iph = ip_hdr(skb); 768 ihl = iph->ihl * 4; 769 770 if (x->encap) { 771 struct xfrm_encap_tmpl *encap = x->encap; 772 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl); 773 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 774 __be16 source; 775 776 switch (x->encap->encap_type) { 777 case TCP_ENCAP_ESPINTCP: 778 source = th->source; 779 break; 780 case UDP_ENCAP_ESPINUDP: 781 case UDP_ENCAP_ESPINUDP_NON_IKE: 782 source = uh->source; 783 break; 784 default: 785 WARN_ON_ONCE(1); 786 err = -EINVAL; 787 goto out; 788 } 789 790 /* 791 * 1) if the NAT-T peer's IP or port changed then 792 * advertize the change to the keying daemon. 793 * This is an inbound SA, so just compare 794 * SRC ports. 795 */ 796 if (iph->saddr != x->props.saddr.a4 || 797 source != encap->encap_sport) { 798 xfrm_address_t ipaddr; 799 800 ipaddr.a4 = iph->saddr; 801 km_new_mapping(x, &ipaddr, source); 802 803 /* XXX: perhaps add an extra 804 * policy check here, to see 805 * if we should allow or 806 * reject a packet from a 807 * different source 808 * address/port. 809 */ 810 } 811 812 /* 813 * 2) ignore UDP/TCP checksums in case 814 * of NAT-T in Transport Mode, or 815 * perform other post-processing fixes 816 * as per draft-ietf-ipsec-udp-encaps-06, 817 * section 3.1.2 818 */ 819 if (x->props.mode == XFRM_MODE_TRANSPORT) 820 skb->ip_summed = CHECKSUM_UNNECESSARY; 821 } 822 823 skb_pull_rcsum(skb, hlen); 824 if (x->props.mode == XFRM_MODE_TUNNEL) 825 skb_reset_transport_header(skb); 826 else 827 skb_set_transport_header(skb, -ihl); 828 829 /* RFC4303: Drop dummy packets without any error */ 830 if (err == IPPROTO_NONE) 831 err = -EINVAL; 832 833 out: 834 return err; 835 } 836 EXPORT_SYMBOL_GPL(esp_input_done2); 837 838 static void esp_input_done(struct crypto_async_request *base, int err) 839 { 840 struct sk_buff *skb = base->data; 841 842 xfrm_input_resume(skb, esp_input_done2(skb, err)); 843 } 844 845 static void esp_input_restore_header(struct sk_buff *skb) 846 { 847 esp_restore_header(skb, 0); 848 __skb_pull(skb, 4); 849 } 850 851 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 852 { 853 struct xfrm_state *x = xfrm_input_state(skb); 854 struct ip_esp_hdr *esph; 855 856 /* For ESN we move the header forward by 4 bytes to 857 * accommodate the high bits. We will move it back after 858 * decryption. 859 */ 860 if ((x->props.flags & XFRM_STATE_ESN)) { 861 esph = skb_push(skb, 4); 862 *seqhi = esph->spi; 863 esph->spi = esph->seq_no; 864 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 865 } 866 } 867 868 static void esp_input_done_esn(struct crypto_async_request *base, int err) 869 { 870 struct sk_buff *skb = base->data; 871 872 esp_input_restore_header(skb); 873 esp_input_done(base, err); 874 } 875 876 /* 877 * Note: detecting truncated vs. non-truncated authentication data is very 878 * expensive, so we only support truncated data, which is the recommended 879 * and common case. 880 */ 881 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 882 { 883 struct crypto_aead *aead = x->data; 884 struct aead_request *req; 885 struct sk_buff *trailer; 886 int ivlen = crypto_aead_ivsize(aead); 887 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 888 int nfrags; 889 int assoclen; 890 int seqhilen; 891 __be32 *seqhi; 892 void *tmp; 893 u8 *iv; 894 struct scatterlist *sg; 895 int err = -EINVAL; 896 897 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) 898 goto out; 899 900 if (elen <= 0) 901 goto out; 902 903 assoclen = sizeof(struct ip_esp_hdr); 904 seqhilen = 0; 905 906 if (x->props.flags & XFRM_STATE_ESN) { 907 seqhilen += sizeof(__be32); 908 assoclen += seqhilen; 909 } 910 911 if (!skb_cloned(skb)) { 912 if (!skb_is_nonlinear(skb)) { 913 nfrags = 1; 914 915 goto skip_cow; 916 } else if (!skb_has_frag_list(skb)) { 917 nfrags = skb_shinfo(skb)->nr_frags; 918 nfrags++; 919 920 goto skip_cow; 921 } 922 } 923 924 err = skb_cow_data(skb, 0, &trailer); 925 if (err < 0) 926 goto out; 927 928 nfrags = err; 929 930 skip_cow: 931 err = -ENOMEM; 932 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 933 if (!tmp) 934 goto out; 935 936 ESP_SKB_CB(skb)->tmp = tmp; 937 seqhi = esp_tmp_extra(tmp); 938 iv = esp_tmp_iv(aead, tmp, seqhilen); 939 req = esp_tmp_req(aead, iv); 940 sg = esp_req_sg(aead, req); 941 942 esp_input_set_header(skb, seqhi); 943 944 sg_init_table(sg, nfrags); 945 err = skb_to_sgvec(skb, sg, 0, skb->len); 946 if (unlikely(err < 0)) { 947 kfree(tmp); 948 goto out; 949 } 950 951 skb->ip_summed = CHECKSUM_NONE; 952 953 if ((x->props.flags & XFRM_STATE_ESN)) 954 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 955 else 956 aead_request_set_callback(req, 0, esp_input_done, skb); 957 958 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 959 aead_request_set_ad(req, assoclen); 960 961 err = crypto_aead_decrypt(req); 962 if (err == -EINPROGRESS) 963 goto out; 964 965 if ((x->props.flags & XFRM_STATE_ESN)) 966 esp_input_restore_header(skb); 967 968 err = esp_input_done2(skb, err); 969 970 out: 971 return err; 972 } 973 974 static int esp4_err(struct sk_buff *skb, u32 info) 975 { 976 struct net *net = dev_net(skb->dev); 977 const struct iphdr *iph = (const struct iphdr *)skb->data; 978 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 979 struct xfrm_state *x; 980 981 switch (icmp_hdr(skb)->type) { 982 case ICMP_DEST_UNREACH: 983 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 984 return 0; 985 break; 986 case ICMP_REDIRECT: 987 break; 988 default: 989 return 0; 990 } 991 992 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 993 esph->spi, IPPROTO_ESP, AF_INET); 994 if (!x) 995 return 0; 996 997 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 998 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP); 999 else 1000 ipv4_redirect(skb, net, 0, IPPROTO_ESP); 1001 xfrm_state_put(x); 1002 1003 return 0; 1004 } 1005 1006 static void esp_destroy(struct xfrm_state *x) 1007 { 1008 struct crypto_aead *aead = x->data; 1009 1010 if (!aead) 1011 return; 1012 1013 crypto_free_aead(aead); 1014 } 1015 1016 static int esp_init_aead(struct xfrm_state *x) 1017 { 1018 char aead_name[CRYPTO_MAX_ALG_NAME]; 1019 struct crypto_aead *aead; 1020 int err; 1021 1022 err = -ENAMETOOLONG; 1023 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1024 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) 1025 goto error; 1026 1027 aead = crypto_alloc_aead(aead_name, 0, 0); 1028 err = PTR_ERR(aead); 1029 if (IS_ERR(aead)) 1030 goto error; 1031 1032 x->data = aead; 1033 1034 err = crypto_aead_setkey(aead, x->aead->alg_key, 1035 (x->aead->alg_key_len + 7) / 8); 1036 if (err) 1037 goto error; 1038 1039 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1040 if (err) 1041 goto error; 1042 1043 error: 1044 return err; 1045 } 1046 1047 static int esp_init_authenc(struct xfrm_state *x) 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 = -EINVAL; 1059 if (!x->ealg) 1060 goto error; 1061 1062 err = -ENAMETOOLONG; 1063 1064 if ((x->props.flags & XFRM_STATE_ESN)) { 1065 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1066 "%s%sauthencesn(%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 goto error; 1072 } else { 1073 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1074 "%s%sauthenc(%s,%s)%s", 1075 x->geniv ?: "", x->geniv ? "(" : "", 1076 x->aalg ? x->aalg->alg_name : "digest_null", 1077 x->ealg->alg_name, 1078 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1079 goto error; 1080 } 1081 1082 aead = crypto_alloc_aead(authenc_name, 0, 0); 1083 err = PTR_ERR(aead); 1084 if (IS_ERR(aead)) 1085 goto error; 1086 1087 x->data = aead; 1088 1089 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1090 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1091 err = -ENOMEM; 1092 key = kmalloc(keylen, GFP_KERNEL); 1093 if (!key) 1094 goto error; 1095 1096 p = key; 1097 rta = (void *)p; 1098 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1099 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1100 param = RTA_DATA(rta); 1101 p += RTA_SPACE(sizeof(*param)); 1102 1103 if (x->aalg) { 1104 struct xfrm_algo_desc *aalg_desc; 1105 1106 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1107 p += (x->aalg->alg_key_len + 7) / 8; 1108 1109 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1110 BUG_ON(!aalg_desc); 1111 1112 err = -EINVAL; 1113 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1114 crypto_aead_authsize(aead)) { 1115 pr_info("ESP: %s digestsize %u != %hu\n", 1116 x->aalg->alg_name, 1117 crypto_aead_authsize(aead), 1118 aalg_desc->uinfo.auth.icv_fullbits / 8); 1119 goto free_key; 1120 } 1121 1122 err = crypto_aead_setauthsize( 1123 aead, x->aalg->alg_trunc_len / 8); 1124 if (err) 1125 goto free_key; 1126 } 1127 1128 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1129 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1130 1131 err = crypto_aead_setkey(aead, key, keylen); 1132 1133 free_key: 1134 kfree(key); 1135 1136 error: 1137 return err; 1138 } 1139 1140 static int esp_init_state(struct xfrm_state *x) 1141 { 1142 struct crypto_aead *aead; 1143 u32 align; 1144 int err; 1145 1146 x->data = NULL; 1147 1148 if (x->aead) 1149 err = esp_init_aead(x); 1150 else 1151 err = esp_init_authenc(x); 1152 1153 if (err) 1154 goto error; 1155 1156 aead = x->data; 1157 1158 x->props.header_len = sizeof(struct ip_esp_hdr) + 1159 crypto_aead_ivsize(aead); 1160 if (x->props.mode == XFRM_MODE_TUNNEL) 1161 x->props.header_len += sizeof(struct iphdr); 1162 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 1163 x->props.header_len += IPV4_BEET_PHMAXLEN; 1164 if (x->encap) { 1165 struct xfrm_encap_tmpl *encap = x->encap; 1166 1167 switch (encap->encap_type) { 1168 default: 1169 err = -EINVAL; 1170 goto error; 1171 case UDP_ENCAP_ESPINUDP: 1172 x->props.header_len += sizeof(struct udphdr); 1173 break; 1174 case UDP_ENCAP_ESPINUDP_NON_IKE: 1175 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 1176 break; 1177 #ifdef CONFIG_INET_ESPINTCP 1178 case TCP_ENCAP_ESPINTCP: 1179 /* only the length field, TCP encap is done by 1180 * the socket 1181 */ 1182 x->props.header_len += 2; 1183 break; 1184 #endif 1185 } 1186 } 1187 1188 align = ALIGN(crypto_aead_blocksize(aead), 4); 1189 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1190 1191 error: 1192 return err; 1193 } 1194 1195 static int esp4_rcv_cb(struct sk_buff *skb, int err) 1196 { 1197 return 0; 1198 } 1199 1200 static const struct xfrm_type esp_type = 1201 { 1202 .owner = THIS_MODULE, 1203 .proto = IPPROTO_ESP, 1204 .flags = XFRM_TYPE_REPLAY_PROT, 1205 .init_state = esp_init_state, 1206 .destructor = esp_destroy, 1207 .input = esp_input, 1208 .output = esp_output, 1209 }; 1210 1211 static struct xfrm4_protocol esp4_protocol = { 1212 .handler = xfrm4_rcv, 1213 .input_handler = xfrm_input, 1214 .cb_handler = esp4_rcv_cb, 1215 .err_handler = esp4_err, 1216 .priority = 0, 1217 }; 1218 1219 static int __init esp4_init(void) 1220 { 1221 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 1222 pr_info("%s: can't add xfrm type\n", __func__); 1223 return -EAGAIN; 1224 } 1225 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 1226 pr_info("%s: can't add protocol\n", __func__); 1227 xfrm_unregister_type(&esp_type, AF_INET); 1228 return -EAGAIN; 1229 } 1230 return 0; 1231 } 1232 1233 static void __exit esp4_fini(void) 1234 { 1235 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 1236 pr_info("%s: can't remove protocol\n", __func__); 1237 xfrm_unregister_type(&esp_type, AF_INET); 1238 } 1239 1240 module_init(esp4_init); 1241 module_exit(esp4_fini); 1242 MODULE_LICENSE("GPL"); 1243 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1244