1 // SPDX-License-Identifier: GPL-2.0-only 2 #define pr_fmt(fmt) "IPsec: " fmt 3 4 #include <crypto/aead.h> 5 #include <crypto/authenc.h> 6 #include <linux/err.h> 7 #include <linux/module.h> 8 #include <net/ip.h> 9 #include <net/xfrm.h> 10 #include <net/esp.h> 11 #include <linux/scatterlist.h> 12 #include <linux/kernel.h> 13 #include <linux/pfkeyv2.h> 14 #include <linux/rtnetlink.h> 15 #include <linux/slab.h> 16 #include <linux/spinlock.h> 17 #include <linux/in6.h> 18 #include <net/icmp.h> 19 #include <net/protocol.h> 20 #include <net/udp.h> 21 #include <net/tcp.h> 22 #include <net/espintcp.h> 23 24 #include <linux/highmem.h> 25 26 struct esp_skb_cb { 27 struct xfrm_skb_cb xfrm; 28 void *tmp; 29 }; 30 31 struct esp_output_extra { 32 __be32 seqhi; 33 u32 esphoff; 34 }; 35 36 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0])) 37 38 /* 39 * Allocate an AEAD request structure with extra space for SG and IV. 40 * 41 * For alignment considerations the IV is placed at the front, followed 42 * by the request and finally the SG list. 43 * 44 * TODO: Use spare space in skb for this where possible. 45 */ 46 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen) 47 { 48 unsigned int len; 49 50 len = extralen; 51 52 len += crypto_aead_ivsize(aead); 53 54 if (len) { 55 len += crypto_aead_alignmask(aead) & 56 ~(crypto_tfm_ctx_alignment() - 1); 57 len = ALIGN(len, crypto_tfm_ctx_alignment()); 58 } 59 60 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead); 61 len = ALIGN(len, __alignof__(struct scatterlist)); 62 63 len += sizeof(struct scatterlist) * nfrags; 64 65 return kmalloc(len, GFP_ATOMIC); 66 } 67 68 static inline void *esp_tmp_extra(void *tmp) 69 { 70 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra)); 71 } 72 73 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen) 74 { 75 return crypto_aead_ivsize(aead) ? 76 PTR_ALIGN((u8 *)tmp + extralen, 77 crypto_aead_alignmask(aead) + 1) : tmp + extralen; 78 } 79 80 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv) 81 { 82 struct aead_request *req; 83 84 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead), 85 crypto_tfm_ctx_alignment()); 86 aead_request_set_tfm(req, aead); 87 return req; 88 } 89 90 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead, 91 struct aead_request *req) 92 { 93 return (void *)ALIGN((unsigned long)(req + 1) + 94 crypto_aead_reqsize(aead), 95 __alignof__(struct scatterlist)); 96 } 97 98 static void esp_ssg_unref(struct xfrm_state *x, void *tmp) 99 { 100 struct crypto_aead *aead = x->data; 101 int extralen = 0; 102 u8 *iv; 103 struct aead_request *req; 104 struct scatterlist *sg; 105 106 if (x->props.flags & XFRM_STATE_ESN) 107 extralen += sizeof(struct esp_output_extra); 108 109 iv = esp_tmp_iv(aead, tmp, extralen); 110 req = esp_tmp_req(aead, iv); 111 112 /* Unref skb_frag_pages in the src scatterlist if necessary. 113 * Skip the first sg which comes from skb->data. 114 */ 115 if (req->src != req->dst) 116 for (sg = sg_next(req->src); sg; sg = sg_next(sg)) 117 put_page(sg_page(sg)); 118 } 119 120 #ifdef CONFIG_INET_ESPINTCP 121 struct esp_tcp_sk { 122 struct sock *sk; 123 struct rcu_head rcu; 124 }; 125 126 static void esp_free_tcp_sk(struct rcu_head *head) 127 { 128 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu); 129 130 sock_put(esk->sk); 131 kfree(esk); 132 } 133 134 static struct sock *esp_find_tcp_sk(struct xfrm_state *x) 135 { 136 struct xfrm_encap_tmpl *encap = x->encap; 137 struct esp_tcp_sk *esk; 138 __be16 sport, dport; 139 struct sock *nsk; 140 struct sock *sk; 141 142 sk = rcu_dereference(x->encap_sk); 143 if (sk && sk->sk_state == TCP_ESTABLISHED) 144 return sk; 145 146 spin_lock_bh(&x->lock); 147 sport = encap->encap_sport; 148 dport = encap->encap_dport; 149 nsk = rcu_dereference_protected(x->encap_sk, 150 lockdep_is_held(&x->lock)); 151 if (sk && sk == nsk) { 152 esk = kmalloc(sizeof(*esk), GFP_ATOMIC); 153 if (!esk) { 154 spin_unlock_bh(&x->lock); 155 return ERR_PTR(-ENOMEM); 156 } 157 RCU_INIT_POINTER(x->encap_sk, NULL); 158 esk->sk = sk; 159 call_rcu(&esk->rcu, esp_free_tcp_sk); 160 } 161 spin_unlock_bh(&x->lock); 162 163 sk = inet_lookup_established(xs_net(x), &tcp_hashinfo, x->id.daddr.a4, 164 dport, x->props.saddr.a4, sport, 0); 165 if (!sk) 166 return ERR_PTR(-ENOENT); 167 168 if (!tcp_is_ulp_esp(sk)) { 169 sock_put(sk); 170 return ERR_PTR(-EINVAL); 171 } 172 173 spin_lock_bh(&x->lock); 174 nsk = rcu_dereference_protected(x->encap_sk, 175 lockdep_is_held(&x->lock)); 176 if (encap->encap_sport != sport || 177 encap->encap_dport != dport) { 178 sock_put(sk); 179 sk = nsk ?: ERR_PTR(-EREMCHG); 180 } else if (sk == nsk) { 181 sock_put(sk); 182 } else { 183 rcu_assign_pointer(x->encap_sk, sk); 184 } 185 spin_unlock_bh(&x->lock); 186 187 return sk; 188 } 189 190 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) 191 { 192 struct sock *sk; 193 int err; 194 195 rcu_read_lock(); 196 197 sk = esp_find_tcp_sk(x); 198 err = PTR_ERR_OR_ZERO(sk); 199 if (err) 200 goto out; 201 202 bh_lock_sock(sk); 203 if (sock_owned_by_user(sk)) 204 err = espintcp_queue_out(sk, skb); 205 else 206 err = espintcp_push_skb(sk, skb); 207 bh_unlock_sock(sk); 208 209 out: 210 rcu_read_unlock(); 211 return err; 212 } 213 214 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk, 215 struct sk_buff *skb) 216 { 217 struct dst_entry *dst = skb_dst(skb); 218 struct xfrm_state *x = dst->xfrm; 219 220 return esp_output_tcp_finish(x, skb); 221 } 222 223 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 224 { 225 int err; 226 227 local_bh_disable(); 228 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb); 229 local_bh_enable(); 230 231 /* EINPROGRESS just happens to do the right thing. It 232 * actually means that the skb has been consumed and 233 * isn't coming back. 234 */ 235 return err ?: -EINPROGRESS; 236 } 237 #else 238 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 239 { 240 kfree_skb(skb); 241 242 return -EOPNOTSUPP; 243 } 244 #endif 245 246 static void esp_output_done(struct crypto_async_request *base, int err) 247 { 248 struct sk_buff *skb = base->data; 249 struct xfrm_offload *xo = xfrm_offload(skb); 250 void *tmp; 251 struct xfrm_state *x; 252 253 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 254 struct sec_path *sp = skb_sec_path(skb); 255 256 x = sp->xvec[sp->len - 1]; 257 } else { 258 x = skb_dst(skb)->xfrm; 259 } 260 261 tmp = ESP_SKB_CB(skb)->tmp; 262 esp_ssg_unref(x, tmp); 263 kfree(tmp); 264 265 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 266 if (err) { 267 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR); 268 kfree_skb(skb); 269 return; 270 } 271 272 skb_push(skb, skb->data - skb_mac_header(skb)); 273 secpath_reset(skb); 274 xfrm_dev_resume(skb); 275 } else { 276 if (!err && 277 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 278 esp_output_tail_tcp(x, skb); 279 else 280 xfrm_output_resume(skb->sk, skb, err); 281 } 282 } 283 284 /* Move ESP header back into place. */ 285 static void esp_restore_header(struct sk_buff *skb, unsigned int offset) 286 { 287 struct ip_esp_hdr *esph = (void *)(skb->data + offset); 288 void *tmp = ESP_SKB_CB(skb)->tmp; 289 __be32 *seqhi = esp_tmp_extra(tmp); 290 291 esph->seq_no = esph->spi; 292 esph->spi = *seqhi; 293 } 294 295 static void esp_output_restore_header(struct sk_buff *skb) 296 { 297 void *tmp = ESP_SKB_CB(skb)->tmp; 298 struct esp_output_extra *extra = esp_tmp_extra(tmp); 299 300 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff - 301 sizeof(__be32)); 302 } 303 304 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb, 305 struct xfrm_state *x, 306 struct ip_esp_hdr *esph, 307 struct esp_output_extra *extra) 308 { 309 /* For ESN we move the header forward by 4 bytes to 310 * accommodate the high bits. We will move it back after 311 * encryption. 312 */ 313 if ((x->props.flags & XFRM_STATE_ESN)) { 314 __u32 seqhi; 315 struct xfrm_offload *xo = xfrm_offload(skb); 316 317 if (xo) 318 seqhi = xo->seq.hi; 319 else 320 seqhi = XFRM_SKB_CB(skb)->seq.output.hi; 321 322 extra->esphoff = (unsigned char *)esph - 323 skb_transport_header(skb); 324 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4); 325 extra->seqhi = esph->spi; 326 esph->seq_no = htonl(seqhi); 327 } 328 329 esph->spi = x->id.spi; 330 331 return esph; 332 } 333 334 static void esp_output_done_esn(struct crypto_async_request *base, int err) 335 { 336 struct sk_buff *skb = base->data; 337 338 esp_output_restore_header(skb); 339 esp_output_done(base, err); 340 } 341 342 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb, 343 int encap_type, 344 struct esp_info *esp, 345 __be16 sport, 346 __be16 dport) 347 { 348 struct udphdr *uh; 349 __be32 *udpdata32; 350 unsigned int len; 351 352 len = skb->len + esp->tailen - skb_transport_offset(skb); 353 if (len + sizeof(struct iphdr) > IP_MAX_MTU) 354 return ERR_PTR(-EMSGSIZE); 355 356 uh = (struct udphdr *)esp->esph; 357 uh->source = sport; 358 uh->dest = dport; 359 uh->len = htons(len); 360 uh->check = 0; 361 362 *skb_mac_header(skb) = IPPROTO_UDP; 363 364 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) { 365 udpdata32 = (__be32 *)(uh + 1); 366 udpdata32[0] = udpdata32[1] = 0; 367 return (struct ip_esp_hdr *)(udpdata32 + 2); 368 } 369 370 return (struct ip_esp_hdr *)(uh + 1); 371 } 372 373 #ifdef CONFIG_INET_ESPINTCP 374 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 375 struct sk_buff *skb, 376 struct esp_info *esp) 377 { 378 __be16 *lenp = (void *)esp->esph; 379 struct ip_esp_hdr *esph; 380 unsigned int len; 381 struct sock *sk; 382 383 len = skb->len + esp->tailen - skb_transport_offset(skb); 384 if (len > IP_MAX_MTU) 385 return ERR_PTR(-EMSGSIZE); 386 387 rcu_read_lock(); 388 sk = esp_find_tcp_sk(x); 389 rcu_read_unlock(); 390 391 if (IS_ERR(sk)) 392 return ERR_CAST(sk); 393 394 *lenp = htons(len); 395 esph = (struct ip_esp_hdr *)(lenp + 1); 396 397 return esph; 398 } 399 #else 400 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 401 struct sk_buff *skb, 402 struct esp_info *esp) 403 { 404 return ERR_PTR(-EOPNOTSUPP); 405 } 406 #endif 407 408 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb, 409 struct esp_info *esp) 410 { 411 struct xfrm_encap_tmpl *encap = x->encap; 412 struct ip_esp_hdr *esph; 413 __be16 sport, dport; 414 int encap_type; 415 416 spin_lock_bh(&x->lock); 417 sport = encap->encap_sport; 418 dport = encap->encap_dport; 419 encap_type = encap->encap_type; 420 spin_unlock_bh(&x->lock); 421 422 switch (encap_type) { 423 default: 424 case UDP_ENCAP_ESPINUDP: 425 case UDP_ENCAP_ESPINUDP_NON_IKE: 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 unsigned int allocsz; 450 451 /* this is non-NULL only with TCP/UDP Encapsulation */ 452 if (x->encap) { 453 int err = esp_output_encap(x, skb, esp); 454 455 if (err < 0) 456 return err; 457 } 458 459 allocsz = ALIGN(skb->data_len + tailen, L1_CACHE_BYTES); 460 if (allocsz > ESP_SKB_FRAG_MAXSIZE) 461 goto cow; 462 463 if (!skb_cloned(skb)) { 464 if (tailen <= skb_tailroom(skb)) { 465 nfrags = 1; 466 trailer = skb; 467 tail = skb_tail_pointer(trailer); 468 469 goto skip_cow; 470 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 471 && !skb_has_frag_list(skb)) { 472 int allocsize; 473 struct sock *sk = skb->sk; 474 struct page_frag *pfrag = &x->xfrag; 475 476 esp->inplace = false; 477 478 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 479 480 spin_lock_bh(&x->lock); 481 482 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 483 spin_unlock_bh(&x->lock); 484 goto cow; 485 } 486 487 page = pfrag->page; 488 get_page(page); 489 490 tail = page_address(page) + pfrag->offset; 491 492 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 493 494 nfrags = skb_shinfo(skb)->nr_frags; 495 496 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 497 tailen); 498 skb_shinfo(skb)->nr_frags = ++nfrags; 499 500 pfrag->offset = pfrag->offset + allocsize; 501 502 spin_unlock_bh(&x->lock); 503 504 nfrags++; 505 506 skb->len += tailen; 507 skb->data_len += tailen; 508 skb->truesize += tailen; 509 if (sk && sk_fullsock(sk)) 510 refcount_add(tailen, &sk->sk_wmem_alloc); 511 512 goto out; 513 } 514 } 515 516 cow: 517 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 518 519 nfrags = skb_cow_data(skb, tailen, &trailer); 520 if (nfrags < 0) 521 goto out; 522 tail = skb_tail_pointer(trailer); 523 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 524 525 skip_cow: 526 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 527 pskb_put(skb, trailer, tailen); 528 529 out: 530 return nfrags; 531 } 532 EXPORT_SYMBOL_GPL(esp_output_head); 533 534 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 535 { 536 u8 *iv; 537 int alen; 538 void *tmp; 539 int ivlen; 540 int assoclen; 541 int extralen; 542 struct page *page; 543 struct ip_esp_hdr *esph; 544 struct crypto_aead *aead; 545 struct aead_request *req; 546 struct scatterlist *sg, *dsg; 547 struct esp_output_extra *extra; 548 int err = -ENOMEM; 549 550 assoclen = sizeof(struct ip_esp_hdr); 551 extralen = 0; 552 553 if (x->props.flags & XFRM_STATE_ESN) { 554 extralen += sizeof(*extra); 555 assoclen += sizeof(__be32); 556 } 557 558 aead = x->data; 559 alen = crypto_aead_authsize(aead); 560 ivlen = crypto_aead_ivsize(aead); 561 562 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 563 if (!tmp) 564 goto error; 565 566 extra = esp_tmp_extra(tmp); 567 iv = esp_tmp_iv(aead, tmp, extralen); 568 req = esp_tmp_req(aead, iv); 569 sg = esp_req_sg(aead, req); 570 571 if (esp->inplace) 572 dsg = sg; 573 else 574 dsg = &sg[esp->nfrags]; 575 576 esph = esp_output_set_extra(skb, x, esp->esph, extra); 577 esp->esph = esph; 578 579 sg_init_table(sg, esp->nfrags); 580 err = skb_to_sgvec(skb, sg, 581 (unsigned char *)esph - skb->data, 582 assoclen + ivlen + esp->clen + alen); 583 if (unlikely(err < 0)) 584 goto error_free; 585 586 if (!esp->inplace) { 587 int allocsize; 588 struct page_frag *pfrag = &x->xfrag; 589 590 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 591 592 spin_lock_bh(&x->lock); 593 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 594 spin_unlock_bh(&x->lock); 595 goto error_free; 596 } 597 598 skb_shinfo(skb)->nr_frags = 1; 599 600 page = pfrag->page; 601 get_page(page); 602 /* replace page frags in skb with new page */ 603 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 604 pfrag->offset = pfrag->offset + allocsize; 605 spin_unlock_bh(&x->lock); 606 607 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 608 err = skb_to_sgvec(skb, dsg, 609 (unsigned char *)esph - skb->data, 610 assoclen + ivlen + esp->clen + alen); 611 if (unlikely(err < 0)) 612 goto error_free; 613 } 614 615 if ((x->props.flags & XFRM_STATE_ESN)) 616 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 617 else 618 aead_request_set_callback(req, 0, esp_output_done, skb); 619 620 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 621 aead_request_set_ad(req, assoclen); 622 623 memset(iv, 0, ivlen); 624 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 625 min(ivlen, 8)); 626 627 ESP_SKB_CB(skb)->tmp = tmp; 628 err = crypto_aead_encrypt(req); 629 630 switch (err) { 631 case -EINPROGRESS: 632 goto error; 633 634 case -ENOSPC: 635 err = NET_XMIT_DROP; 636 break; 637 638 case 0: 639 if ((x->props.flags & XFRM_STATE_ESN)) 640 esp_output_restore_header(skb); 641 } 642 643 if (sg != dsg) 644 esp_ssg_unref(x, tmp); 645 646 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 647 err = esp_output_tail_tcp(x, skb); 648 649 error_free: 650 kfree(tmp); 651 error: 652 return err; 653 } 654 EXPORT_SYMBOL_GPL(esp_output_tail); 655 656 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 657 { 658 int alen; 659 int blksize; 660 struct ip_esp_hdr *esph; 661 struct crypto_aead *aead; 662 struct esp_info esp; 663 664 esp.inplace = true; 665 666 esp.proto = *skb_mac_header(skb); 667 *skb_mac_header(skb) = IPPROTO_ESP; 668 669 /* skb is pure payload to encrypt */ 670 671 aead = x->data; 672 alen = crypto_aead_authsize(aead); 673 674 esp.tfclen = 0; 675 if (x->tfcpad) { 676 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 677 u32 padto; 678 679 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 680 if (skb->len < padto) 681 esp.tfclen = padto - skb->len; 682 } 683 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 684 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 685 esp.plen = esp.clen - skb->len - esp.tfclen; 686 esp.tailen = esp.tfclen + esp.plen + alen; 687 688 esp.esph = ip_esp_hdr(skb); 689 690 esp.nfrags = esp_output_head(x, skb, &esp); 691 if (esp.nfrags < 0) 692 return esp.nfrags; 693 694 esph = esp.esph; 695 esph->spi = x->id.spi; 696 697 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 698 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 699 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 700 701 skb_push(skb, -skb_network_offset(skb)); 702 703 return esp_output_tail(x, skb, &esp); 704 } 705 706 static inline int esp_remove_trailer(struct sk_buff *skb) 707 { 708 struct xfrm_state *x = xfrm_input_state(skb); 709 struct xfrm_offload *xo = xfrm_offload(skb); 710 struct crypto_aead *aead = x->data; 711 int alen, hlen, elen; 712 int padlen, trimlen; 713 __wsum csumdiff; 714 u8 nexthdr[2]; 715 int ret; 716 717 alen = crypto_aead_authsize(aead); 718 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 719 elen = skb->len - hlen; 720 721 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) { 722 ret = xo->proto; 723 goto out; 724 } 725 726 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) 727 BUG(); 728 729 ret = -EINVAL; 730 padlen = nexthdr[0]; 731 if (padlen + 2 + alen >= elen) { 732 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 733 padlen + 2, elen - alen); 734 goto out; 735 } 736 737 trimlen = alen + padlen + 2; 738 if (skb->ip_summed == CHECKSUM_COMPLETE) { 739 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 740 skb->csum = csum_block_sub(skb->csum, csumdiff, 741 skb->len - trimlen); 742 } 743 pskb_trim(skb, skb->len - trimlen); 744 745 ret = nexthdr[1]; 746 747 out: 748 return ret; 749 } 750 751 int esp_input_done2(struct sk_buff *skb, int err) 752 { 753 const struct iphdr *iph; 754 struct xfrm_state *x = xfrm_input_state(skb); 755 struct xfrm_offload *xo = xfrm_offload(skb); 756 struct crypto_aead *aead = x->data; 757 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 758 int ihl; 759 760 if (!xo || !(xo->flags & CRYPTO_DONE)) 761 kfree(ESP_SKB_CB(skb)->tmp); 762 763 if (unlikely(err)) 764 goto out; 765 766 err = esp_remove_trailer(skb); 767 if (unlikely(err < 0)) 768 goto out; 769 770 iph = ip_hdr(skb); 771 ihl = iph->ihl * 4; 772 773 if (x->encap) { 774 struct xfrm_encap_tmpl *encap = x->encap; 775 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl); 776 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 777 __be16 source; 778 779 switch (x->encap->encap_type) { 780 case TCP_ENCAP_ESPINTCP: 781 source = th->source; 782 break; 783 case UDP_ENCAP_ESPINUDP: 784 case UDP_ENCAP_ESPINUDP_NON_IKE: 785 source = uh->source; 786 break; 787 default: 788 WARN_ON_ONCE(1); 789 err = -EINVAL; 790 goto out; 791 } 792 793 /* 794 * 1) if the NAT-T peer's IP or port changed then 795 * advertize the change to the keying daemon. 796 * This is an inbound SA, so just compare 797 * SRC ports. 798 */ 799 if (iph->saddr != x->props.saddr.a4 || 800 source != encap->encap_sport) { 801 xfrm_address_t ipaddr; 802 803 ipaddr.a4 = iph->saddr; 804 km_new_mapping(x, &ipaddr, source); 805 806 /* XXX: perhaps add an extra 807 * policy check here, to see 808 * if we should allow or 809 * reject a packet from a 810 * different source 811 * address/port. 812 */ 813 } 814 815 /* 816 * 2) ignore UDP/TCP checksums in case 817 * of NAT-T in Transport Mode, or 818 * perform other post-processing fixes 819 * as per draft-ietf-ipsec-udp-encaps-06, 820 * section 3.1.2 821 */ 822 if (x->props.mode == XFRM_MODE_TRANSPORT) 823 skb->ip_summed = CHECKSUM_UNNECESSARY; 824 } 825 826 skb_pull_rcsum(skb, hlen); 827 if (x->props.mode == XFRM_MODE_TUNNEL) 828 skb_reset_transport_header(skb); 829 else 830 skb_set_transport_header(skb, -ihl); 831 832 /* RFC4303: Drop dummy packets without any error */ 833 if (err == IPPROTO_NONE) 834 err = -EINVAL; 835 836 out: 837 return err; 838 } 839 EXPORT_SYMBOL_GPL(esp_input_done2); 840 841 static void esp_input_done(struct crypto_async_request *base, int err) 842 { 843 struct sk_buff *skb = base->data; 844 845 xfrm_input_resume(skb, esp_input_done2(skb, err)); 846 } 847 848 static void esp_input_restore_header(struct sk_buff *skb) 849 { 850 esp_restore_header(skb, 0); 851 __skb_pull(skb, 4); 852 } 853 854 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 855 { 856 struct xfrm_state *x = xfrm_input_state(skb); 857 struct ip_esp_hdr *esph; 858 859 /* For ESN we move the header forward by 4 bytes to 860 * accommodate the high bits. We will move it back after 861 * decryption. 862 */ 863 if ((x->props.flags & XFRM_STATE_ESN)) { 864 esph = skb_push(skb, 4); 865 *seqhi = esph->spi; 866 esph->spi = esph->seq_no; 867 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 868 } 869 } 870 871 static void esp_input_done_esn(struct crypto_async_request *base, int err) 872 { 873 struct sk_buff *skb = base->data; 874 875 esp_input_restore_header(skb); 876 esp_input_done(base, err); 877 } 878 879 /* 880 * Note: detecting truncated vs. non-truncated authentication data is very 881 * expensive, so we only support truncated data, which is the recommended 882 * and common case. 883 */ 884 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 885 { 886 struct crypto_aead *aead = x->data; 887 struct aead_request *req; 888 struct sk_buff *trailer; 889 int ivlen = crypto_aead_ivsize(aead); 890 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 891 int nfrags; 892 int assoclen; 893 int seqhilen; 894 __be32 *seqhi; 895 void *tmp; 896 u8 *iv; 897 struct scatterlist *sg; 898 int err = -EINVAL; 899 900 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) 901 goto out; 902 903 if (elen <= 0) 904 goto out; 905 906 assoclen = sizeof(struct ip_esp_hdr); 907 seqhilen = 0; 908 909 if (x->props.flags & XFRM_STATE_ESN) { 910 seqhilen += sizeof(__be32); 911 assoclen += seqhilen; 912 } 913 914 if (!skb_cloned(skb)) { 915 if (!skb_is_nonlinear(skb)) { 916 nfrags = 1; 917 918 goto skip_cow; 919 } else if (!skb_has_frag_list(skb)) { 920 nfrags = skb_shinfo(skb)->nr_frags; 921 nfrags++; 922 923 goto skip_cow; 924 } 925 } 926 927 err = skb_cow_data(skb, 0, &trailer); 928 if (err < 0) 929 goto out; 930 931 nfrags = err; 932 933 skip_cow: 934 err = -ENOMEM; 935 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 936 if (!tmp) 937 goto out; 938 939 ESP_SKB_CB(skb)->tmp = tmp; 940 seqhi = esp_tmp_extra(tmp); 941 iv = esp_tmp_iv(aead, tmp, seqhilen); 942 req = esp_tmp_req(aead, iv); 943 sg = esp_req_sg(aead, req); 944 945 esp_input_set_header(skb, seqhi); 946 947 sg_init_table(sg, nfrags); 948 err = skb_to_sgvec(skb, sg, 0, skb->len); 949 if (unlikely(err < 0)) { 950 kfree(tmp); 951 goto out; 952 } 953 954 skb->ip_summed = CHECKSUM_NONE; 955 956 if ((x->props.flags & XFRM_STATE_ESN)) 957 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 958 else 959 aead_request_set_callback(req, 0, esp_input_done, skb); 960 961 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 962 aead_request_set_ad(req, assoclen); 963 964 err = crypto_aead_decrypt(req); 965 if (err == -EINPROGRESS) 966 goto out; 967 968 if ((x->props.flags & XFRM_STATE_ESN)) 969 esp_input_restore_header(skb); 970 971 err = esp_input_done2(skb, err); 972 973 out: 974 return err; 975 } 976 977 static int esp4_err(struct sk_buff *skb, u32 info) 978 { 979 struct net *net = dev_net(skb->dev); 980 const struct iphdr *iph = (const struct iphdr *)skb->data; 981 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 982 struct xfrm_state *x; 983 984 switch (icmp_hdr(skb)->type) { 985 case ICMP_DEST_UNREACH: 986 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 987 return 0; 988 break; 989 case ICMP_REDIRECT: 990 break; 991 default: 992 return 0; 993 } 994 995 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 996 esph->spi, IPPROTO_ESP, AF_INET); 997 if (!x) 998 return 0; 999 1000 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 1001 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP); 1002 else 1003 ipv4_redirect(skb, net, 0, IPPROTO_ESP); 1004 xfrm_state_put(x); 1005 1006 return 0; 1007 } 1008 1009 static void esp_destroy(struct xfrm_state *x) 1010 { 1011 struct crypto_aead *aead = x->data; 1012 1013 if (!aead) 1014 return; 1015 1016 crypto_free_aead(aead); 1017 } 1018 1019 static int esp_init_aead(struct xfrm_state *x) 1020 { 1021 char aead_name[CRYPTO_MAX_ALG_NAME]; 1022 struct crypto_aead *aead; 1023 int err; 1024 1025 err = -ENAMETOOLONG; 1026 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1027 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) 1028 goto error; 1029 1030 aead = crypto_alloc_aead(aead_name, 0, 0); 1031 err = PTR_ERR(aead); 1032 if (IS_ERR(aead)) 1033 goto error; 1034 1035 x->data = aead; 1036 1037 err = crypto_aead_setkey(aead, x->aead->alg_key, 1038 (x->aead->alg_key_len + 7) / 8); 1039 if (err) 1040 goto error; 1041 1042 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1043 if (err) 1044 goto error; 1045 1046 error: 1047 return err; 1048 } 1049 1050 static int esp_init_authenc(struct xfrm_state *x) 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 = -EINVAL; 1062 if (!x->ealg) 1063 goto error; 1064 1065 err = -ENAMETOOLONG; 1066 1067 if ((x->props.flags & XFRM_STATE_ESN)) { 1068 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1069 "%s%sauthencesn(%s,%s)%s", 1070 x->geniv ?: "", x->geniv ? "(" : "", 1071 x->aalg ? x->aalg->alg_name : "digest_null", 1072 x->ealg->alg_name, 1073 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1074 goto error; 1075 } else { 1076 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1077 "%s%sauthenc(%s,%s)%s", 1078 x->geniv ?: "", x->geniv ? "(" : "", 1079 x->aalg ? x->aalg->alg_name : "digest_null", 1080 x->ealg->alg_name, 1081 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1082 goto error; 1083 } 1084 1085 aead = crypto_alloc_aead(authenc_name, 0, 0); 1086 err = PTR_ERR(aead); 1087 if (IS_ERR(aead)) 1088 goto error; 1089 1090 x->data = aead; 1091 1092 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1093 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1094 err = -ENOMEM; 1095 key = kmalloc(keylen, GFP_KERNEL); 1096 if (!key) 1097 goto error; 1098 1099 p = key; 1100 rta = (void *)p; 1101 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1102 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1103 param = RTA_DATA(rta); 1104 p += RTA_SPACE(sizeof(*param)); 1105 1106 if (x->aalg) { 1107 struct xfrm_algo_desc *aalg_desc; 1108 1109 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1110 p += (x->aalg->alg_key_len + 7) / 8; 1111 1112 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1113 BUG_ON(!aalg_desc); 1114 1115 err = -EINVAL; 1116 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1117 crypto_aead_authsize(aead)) { 1118 pr_info("ESP: %s digestsize %u != %hu\n", 1119 x->aalg->alg_name, 1120 crypto_aead_authsize(aead), 1121 aalg_desc->uinfo.auth.icv_fullbits / 8); 1122 goto free_key; 1123 } 1124 1125 err = crypto_aead_setauthsize( 1126 aead, x->aalg->alg_trunc_len / 8); 1127 if (err) 1128 goto free_key; 1129 } 1130 1131 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1132 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1133 1134 err = crypto_aead_setkey(aead, key, keylen); 1135 1136 free_key: 1137 kfree(key); 1138 1139 error: 1140 return err; 1141 } 1142 1143 static int esp_init_state(struct xfrm_state *x) 1144 { 1145 struct crypto_aead *aead; 1146 u32 align; 1147 int err; 1148 1149 x->data = NULL; 1150 1151 if (x->aead) 1152 err = esp_init_aead(x); 1153 else 1154 err = esp_init_authenc(x); 1155 1156 if (err) 1157 goto error; 1158 1159 aead = x->data; 1160 1161 x->props.header_len = sizeof(struct ip_esp_hdr) + 1162 crypto_aead_ivsize(aead); 1163 if (x->props.mode == XFRM_MODE_TUNNEL) 1164 x->props.header_len += sizeof(struct iphdr); 1165 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 1166 x->props.header_len += IPV4_BEET_PHMAXLEN; 1167 if (x->encap) { 1168 struct xfrm_encap_tmpl *encap = x->encap; 1169 1170 switch (encap->encap_type) { 1171 default: 1172 err = -EINVAL; 1173 goto error; 1174 case UDP_ENCAP_ESPINUDP: 1175 x->props.header_len += sizeof(struct udphdr); 1176 break; 1177 case UDP_ENCAP_ESPINUDP_NON_IKE: 1178 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 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_LICENSE("GPL"); 1246 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1247