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, 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 * accomodate 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 u8 *vaddr; 447 int nfrags; 448 int esph_offset; 449 struct page *page; 450 struct sk_buff *trailer; 451 int tailen = esp->tailen; 452 453 /* this is non-NULL only with TCP/UDP Encapsulation */ 454 if (x->encap) { 455 int err = esp_output_encap(x, skb, esp); 456 457 if (err < 0) 458 return err; 459 } 460 461 if (!skb_cloned(skb)) { 462 if (tailen <= skb_tailroom(skb)) { 463 nfrags = 1; 464 trailer = skb; 465 tail = skb_tail_pointer(trailer); 466 467 goto skip_cow; 468 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 469 && !skb_has_frag_list(skb)) { 470 int allocsize; 471 struct sock *sk = skb->sk; 472 struct page_frag *pfrag = &x->xfrag; 473 474 esp->inplace = false; 475 476 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 477 478 spin_lock_bh(&x->lock); 479 480 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 481 spin_unlock_bh(&x->lock); 482 goto cow; 483 } 484 485 page = pfrag->page; 486 get_page(page); 487 488 vaddr = kmap_atomic(page); 489 490 tail = vaddr + pfrag->offset; 491 492 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 493 494 kunmap_atomic(vaddr); 495 496 nfrags = skb_shinfo(skb)->nr_frags; 497 498 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 499 tailen); 500 skb_shinfo(skb)->nr_frags = ++nfrags; 501 502 pfrag->offset = pfrag->offset + allocsize; 503 504 spin_unlock_bh(&x->lock); 505 506 nfrags++; 507 508 skb->len += tailen; 509 skb->data_len += tailen; 510 skb->truesize += tailen; 511 if (sk && sk_fullsock(sk)) 512 refcount_add(tailen, &sk->sk_wmem_alloc); 513 514 goto out; 515 } 516 } 517 518 cow: 519 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 520 521 nfrags = skb_cow_data(skb, tailen, &trailer); 522 if (nfrags < 0) 523 goto out; 524 tail = skb_tail_pointer(trailer); 525 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 526 527 skip_cow: 528 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 529 pskb_put(skb, trailer, tailen); 530 531 out: 532 return nfrags; 533 } 534 EXPORT_SYMBOL_GPL(esp_output_head); 535 536 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 537 { 538 u8 *iv; 539 int alen; 540 void *tmp; 541 int ivlen; 542 int assoclen; 543 int extralen; 544 struct page *page; 545 struct ip_esp_hdr *esph; 546 struct crypto_aead *aead; 547 struct aead_request *req; 548 struct scatterlist *sg, *dsg; 549 struct esp_output_extra *extra; 550 int err = -ENOMEM; 551 552 assoclen = sizeof(struct ip_esp_hdr); 553 extralen = 0; 554 555 if (x->props.flags & XFRM_STATE_ESN) { 556 extralen += sizeof(*extra); 557 assoclen += sizeof(__be32); 558 } 559 560 aead = x->data; 561 alen = crypto_aead_authsize(aead); 562 ivlen = crypto_aead_ivsize(aead); 563 564 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 565 if (!tmp) 566 goto error; 567 568 extra = esp_tmp_extra(tmp); 569 iv = esp_tmp_iv(aead, tmp, extralen); 570 req = esp_tmp_req(aead, iv); 571 sg = esp_req_sg(aead, req); 572 573 if (esp->inplace) 574 dsg = sg; 575 else 576 dsg = &sg[esp->nfrags]; 577 578 esph = esp_output_set_extra(skb, x, esp->esph, extra); 579 esp->esph = esph; 580 581 sg_init_table(sg, esp->nfrags); 582 err = skb_to_sgvec(skb, sg, 583 (unsigned char *)esph - skb->data, 584 assoclen + ivlen + esp->clen + alen); 585 if (unlikely(err < 0)) 586 goto error_free; 587 588 if (!esp->inplace) { 589 int allocsize; 590 struct page_frag *pfrag = &x->xfrag; 591 592 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 593 594 spin_lock_bh(&x->lock); 595 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 596 spin_unlock_bh(&x->lock); 597 goto error_free; 598 } 599 600 skb_shinfo(skb)->nr_frags = 1; 601 602 page = pfrag->page; 603 get_page(page); 604 /* replace page frags in skb with new page */ 605 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 606 pfrag->offset = pfrag->offset + allocsize; 607 spin_unlock_bh(&x->lock); 608 609 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 610 err = skb_to_sgvec(skb, dsg, 611 (unsigned char *)esph - skb->data, 612 assoclen + ivlen + esp->clen + alen); 613 if (unlikely(err < 0)) 614 goto error_free; 615 } 616 617 if ((x->props.flags & XFRM_STATE_ESN)) 618 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 619 else 620 aead_request_set_callback(req, 0, esp_output_done, skb); 621 622 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 623 aead_request_set_ad(req, assoclen); 624 625 memset(iv, 0, ivlen); 626 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 627 min(ivlen, 8)); 628 629 ESP_SKB_CB(skb)->tmp = tmp; 630 err = crypto_aead_encrypt(req); 631 632 switch (err) { 633 case -EINPROGRESS: 634 goto error; 635 636 case -ENOSPC: 637 err = NET_XMIT_DROP; 638 break; 639 640 case 0: 641 if ((x->props.flags & XFRM_STATE_ESN)) 642 esp_output_restore_header(skb); 643 } 644 645 if (sg != dsg) 646 esp_ssg_unref(x, tmp); 647 648 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 649 err = esp_output_tail_tcp(x, skb); 650 651 error_free: 652 kfree(tmp); 653 error: 654 return err; 655 } 656 EXPORT_SYMBOL_GPL(esp_output_tail); 657 658 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 659 { 660 int alen; 661 int blksize; 662 struct ip_esp_hdr *esph; 663 struct crypto_aead *aead; 664 struct esp_info esp; 665 666 esp.inplace = true; 667 668 esp.proto = *skb_mac_header(skb); 669 *skb_mac_header(skb) = IPPROTO_ESP; 670 671 /* skb is pure payload to encrypt */ 672 673 aead = x->data; 674 alen = crypto_aead_authsize(aead); 675 676 esp.tfclen = 0; 677 if (x->tfcpad) { 678 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 679 u32 padto; 680 681 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 682 if (skb->len < padto) 683 esp.tfclen = padto - skb->len; 684 } 685 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 686 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 687 esp.plen = esp.clen - skb->len - esp.tfclen; 688 esp.tailen = esp.tfclen + esp.plen + alen; 689 690 esp.esph = ip_esp_hdr(skb); 691 692 esp.nfrags = esp_output_head(x, skb, &esp); 693 if (esp.nfrags < 0) 694 return esp.nfrags; 695 696 esph = esp.esph; 697 esph->spi = x->id.spi; 698 699 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 700 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 701 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 702 703 skb_push(skb, -skb_network_offset(skb)); 704 705 return esp_output_tail(x, skb, &esp); 706 } 707 708 static inline int esp_remove_trailer(struct sk_buff *skb) 709 { 710 struct xfrm_state *x = xfrm_input_state(skb); 711 struct xfrm_offload *xo = xfrm_offload(skb); 712 struct crypto_aead *aead = x->data; 713 int alen, hlen, elen; 714 int padlen, trimlen; 715 __wsum csumdiff; 716 u8 nexthdr[2]; 717 int ret; 718 719 alen = crypto_aead_authsize(aead); 720 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 721 elen = skb->len - hlen; 722 723 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) { 724 ret = xo->proto; 725 goto out; 726 } 727 728 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) 729 BUG(); 730 731 ret = -EINVAL; 732 padlen = nexthdr[0]; 733 if (padlen + 2 + alen >= elen) { 734 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 735 padlen + 2, elen - alen); 736 goto out; 737 } 738 739 trimlen = alen + padlen + 2; 740 if (skb->ip_summed == CHECKSUM_COMPLETE) { 741 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 742 skb->csum = csum_block_sub(skb->csum, csumdiff, 743 skb->len - trimlen); 744 } 745 pskb_trim(skb, skb->len - trimlen); 746 747 ret = nexthdr[1]; 748 749 out: 750 return ret; 751 } 752 753 int esp_input_done2(struct sk_buff *skb, int err) 754 { 755 const struct iphdr *iph; 756 struct xfrm_state *x = xfrm_input_state(skb); 757 struct xfrm_offload *xo = xfrm_offload(skb); 758 struct crypto_aead *aead = x->data; 759 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 760 int ihl; 761 762 if (!xo || (xo && !(xo->flags & CRYPTO_DONE))) 763 kfree(ESP_SKB_CB(skb)->tmp); 764 765 if (unlikely(err)) 766 goto out; 767 768 err = esp_remove_trailer(skb); 769 if (unlikely(err < 0)) 770 goto out; 771 772 iph = ip_hdr(skb); 773 ihl = iph->ihl * 4; 774 775 if (x->encap) { 776 struct xfrm_encap_tmpl *encap = x->encap; 777 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl); 778 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 779 __be16 source; 780 781 switch (x->encap->encap_type) { 782 case TCP_ENCAP_ESPINTCP: 783 source = th->source; 784 break; 785 case UDP_ENCAP_ESPINUDP: 786 case UDP_ENCAP_ESPINUDP_NON_IKE: 787 source = uh->source; 788 break; 789 default: 790 WARN_ON_ONCE(1); 791 err = -EINVAL; 792 goto out; 793 } 794 795 /* 796 * 1) if the NAT-T peer's IP or port changed then 797 * advertize the change to the keying daemon. 798 * This is an inbound SA, so just compare 799 * SRC ports. 800 */ 801 if (iph->saddr != x->props.saddr.a4 || 802 source != encap->encap_sport) { 803 xfrm_address_t ipaddr; 804 805 ipaddr.a4 = iph->saddr; 806 km_new_mapping(x, &ipaddr, source); 807 808 /* XXX: perhaps add an extra 809 * policy check here, to see 810 * if we should allow or 811 * reject a packet from a 812 * different source 813 * address/port. 814 */ 815 } 816 817 /* 818 * 2) ignore UDP/TCP checksums in case 819 * of NAT-T in Transport Mode, or 820 * perform other post-processing fixes 821 * as per draft-ietf-ipsec-udp-encaps-06, 822 * section 3.1.2 823 */ 824 if (x->props.mode == XFRM_MODE_TRANSPORT) 825 skb->ip_summed = CHECKSUM_UNNECESSARY; 826 } 827 828 skb_pull_rcsum(skb, hlen); 829 if (x->props.mode == XFRM_MODE_TUNNEL) 830 skb_reset_transport_header(skb); 831 else 832 skb_set_transport_header(skb, -ihl); 833 834 /* RFC4303: Drop dummy packets without any error */ 835 if (err == IPPROTO_NONE) 836 err = -EINVAL; 837 838 out: 839 return err; 840 } 841 EXPORT_SYMBOL_GPL(esp_input_done2); 842 843 static void esp_input_done(struct crypto_async_request *base, int err) 844 { 845 struct sk_buff *skb = base->data; 846 847 xfrm_input_resume(skb, esp_input_done2(skb, err)); 848 } 849 850 static void esp_input_restore_header(struct sk_buff *skb) 851 { 852 esp_restore_header(skb, 0); 853 __skb_pull(skb, 4); 854 } 855 856 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 857 { 858 struct xfrm_state *x = xfrm_input_state(skb); 859 struct ip_esp_hdr *esph; 860 861 /* For ESN we move the header forward by 4 bytes to 862 * accomodate the high bits. We will move it back after 863 * decryption. 864 */ 865 if ((x->props.flags & XFRM_STATE_ESN)) { 866 esph = skb_push(skb, 4); 867 *seqhi = esph->spi; 868 esph->spi = esph->seq_no; 869 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 870 } 871 } 872 873 static void esp_input_done_esn(struct crypto_async_request *base, int err) 874 { 875 struct sk_buff *skb = base->data; 876 877 esp_input_restore_header(skb); 878 esp_input_done(base, err); 879 } 880 881 /* 882 * Note: detecting truncated vs. non-truncated authentication data is very 883 * expensive, so we only support truncated data, which is the recommended 884 * and common case. 885 */ 886 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 887 { 888 struct crypto_aead *aead = x->data; 889 struct aead_request *req; 890 struct sk_buff *trailer; 891 int ivlen = crypto_aead_ivsize(aead); 892 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 893 int nfrags; 894 int assoclen; 895 int seqhilen; 896 __be32 *seqhi; 897 void *tmp; 898 u8 *iv; 899 struct scatterlist *sg; 900 int err = -EINVAL; 901 902 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) 903 goto out; 904 905 if (elen <= 0) 906 goto out; 907 908 assoclen = sizeof(struct ip_esp_hdr); 909 seqhilen = 0; 910 911 if (x->props.flags & XFRM_STATE_ESN) { 912 seqhilen += sizeof(__be32); 913 assoclen += seqhilen; 914 } 915 916 if (!skb_cloned(skb)) { 917 if (!skb_is_nonlinear(skb)) { 918 nfrags = 1; 919 920 goto skip_cow; 921 } else if (!skb_has_frag_list(skb)) { 922 nfrags = skb_shinfo(skb)->nr_frags; 923 nfrags++; 924 925 goto skip_cow; 926 } 927 } 928 929 err = skb_cow_data(skb, 0, &trailer); 930 if (err < 0) 931 goto out; 932 933 nfrags = err; 934 935 skip_cow: 936 err = -ENOMEM; 937 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 938 if (!tmp) 939 goto out; 940 941 ESP_SKB_CB(skb)->tmp = tmp; 942 seqhi = esp_tmp_extra(tmp); 943 iv = esp_tmp_iv(aead, tmp, seqhilen); 944 req = esp_tmp_req(aead, iv); 945 sg = esp_req_sg(aead, req); 946 947 esp_input_set_header(skb, seqhi); 948 949 sg_init_table(sg, nfrags); 950 err = skb_to_sgvec(skb, sg, 0, skb->len); 951 if (unlikely(err < 0)) { 952 kfree(tmp); 953 goto out; 954 } 955 956 skb->ip_summed = CHECKSUM_NONE; 957 958 if ((x->props.flags & XFRM_STATE_ESN)) 959 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 960 else 961 aead_request_set_callback(req, 0, esp_input_done, skb); 962 963 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 964 aead_request_set_ad(req, assoclen); 965 966 err = crypto_aead_decrypt(req); 967 if (err == -EINPROGRESS) 968 goto out; 969 970 if ((x->props.flags & XFRM_STATE_ESN)) 971 esp_input_restore_header(skb); 972 973 err = esp_input_done2(skb, err); 974 975 out: 976 return err; 977 } 978 979 static int esp4_err(struct sk_buff *skb, u32 info) 980 { 981 struct net *net = dev_net(skb->dev); 982 const struct iphdr *iph = (const struct iphdr *)skb->data; 983 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 984 struct xfrm_state *x; 985 986 switch (icmp_hdr(skb)->type) { 987 case ICMP_DEST_UNREACH: 988 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 989 return 0; 990 case ICMP_REDIRECT: 991 break; 992 default: 993 return 0; 994 } 995 996 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 997 esph->spi, IPPROTO_ESP, AF_INET); 998 if (!x) 999 return 0; 1000 1001 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 1002 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP); 1003 else 1004 ipv4_redirect(skb, net, 0, IPPROTO_ESP); 1005 xfrm_state_put(x); 1006 1007 return 0; 1008 } 1009 1010 static void esp_destroy(struct xfrm_state *x) 1011 { 1012 struct crypto_aead *aead = x->data; 1013 1014 if (!aead) 1015 return; 1016 1017 crypto_free_aead(aead); 1018 } 1019 1020 static int esp_init_aead(struct xfrm_state *x) 1021 { 1022 char aead_name[CRYPTO_MAX_ALG_NAME]; 1023 struct crypto_aead *aead; 1024 int err; 1025 1026 err = -ENAMETOOLONG; 1027 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1028 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) 1029 goto error; 1030 1031 aead = crypto_alloc_aead(aead_name, 0, 0); 1032 err = PTR_ERR(aead); 1033 if (IS_ERR(aead)) 1034 goto error; 1035 1036 x->data = aead; 1037 1038 err = crypto_aead_setkey(aead, x->aead->alg_key, 1039 (x->aead->alg_key_len + 7) / 8); 1040 if (err) 1041 goto error; 1042 1043 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1044 if (err) 1045 goto error; 1046 1047 error: 1048 return err; 1049 } 1050 1051 static int esp_init_authenc(struct xfrm_state *x) 1052 { 1053 struct crypto_aead *aead; 1054 struct crypto_authenc_key_param *param; 1055 struct rtattr *rta; 1056 char *key; 1057 char *p; 1058 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1059 unsigned int keylen; 1060 int err; 1061 1062 err = -EINVAL; 1063 if (!x->ealg) 1064 goto error; 1065 1066 err = -ENAMETOOLONG; 1067 1068 if ((x->props.flags & XFRM_STATE_ESN)) { 1069 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1070 "%s%sauthencesn(%s,%s)%s", 1071 x->geniv ?: "", x->geniv ? "(" : "", 1072 x->aalg ? x->aalg->alg_name : "digest_null", 1073 x->ealg->alg_name, 1074 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1075 goto error; 1076 } else { 1077 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1078 "%s%sauthenc(%s,%s)%s", 1079 x->geniv ?: "", x->geniv ? "(" : "", 1080 x->aalg ? x->aalg->alg_name : "digest_null", 1081 x->ealg->alg_name, 1082 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1083 goto error; 1084 } 1085 1086 aead = crypto_alloc_aead(authenc_name, 0, 0); 1087 err = PTR_ERR(aead); 1088 if (IS_ERR(aead)) 1089 goto error; 1090 1091 x->data = aead; 1092 1093 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1094 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1095 err = -ENOMEM; 1096 key = kmalloc(keylen, GFP_KERNEL); 1097 if (!key) 1098 goto error; 1099 1100 p = key; 1101 rta = (void *)p; 1102 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1103 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1104 param = RTA_DATA(rta); 1105 p += RTA_SPACE(sizeof(*param)); 1106 1107 if (x->aalg) { 1108 struct xfrm_algo_desc *aalg_desc; 1109 1110 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1111 p += (x->aalg->alg_key_len + 7) / 8; 1112 1113 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1114 BUG_ON(!aalg_desc); 1115 1116 err = -EINVAL; 1117 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1118 crypto_aead_authsize(aead)) { 1119 pr_info("ESP: %s digestsize %u != %hu\n", 1120 x->aalg->alg_name, 1121 crypto_aead_authsize(aead), 1122 aalg_desc->uinfo.auth.icv_fullbits / 8); 1123 goto free_key; 1124 } 1125 1126 err = crypto_aead_setauthsize( 1127 aead, x->aalg->alg_trunc_len / 8); 1128 if (err) 1129 goto free_key; 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(key); 1139 1140 error: 1141 return err; 1142 } 1143 1144 static int esp_init_state(struct xfrm_state *x) 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); 1154 else 1155 err = esp_init_authenc(x); 1156 1157 if (err) 1158 goto error; 1159 1160 aead = x->data; 1161 1162 x->props.header_len = sizeof(struct ip_esp_hdr) + 1163 crypto_aead_ivsize(aead); 1164 if (x->props.mode == XFRM_MODE_TUNNEL) 1165 x->props.header_len += sizeof(struct iphdr); 1166 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 1167 x->props.header_len += IPV4_BEET_PHMAXLEN; 1168 if (x->encap) { 1169 struct xfrm_encap_tmpl *encap = x->encap; 1170 1171 switch (encap->encap_type) { 1172 default: 1173 err = -EINVAL; 1174 goto error; 1175 case UDP_ENCAP_ESPINUDP: 1176 x->props.header_len += sizeof(struct udphdr); 1177 break; 1178 case UDP_ENCAP_ESPINUDP_NON_IKE: 1179 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 1180 break; 1181 #ifdef CONFIG_INET_ESPINTCP 1182 case TCP_ENCAP_ESPINTCP: 1183 /* only the length field, TCP encap is done by 1184 * the socket 1185 */ 1186 x->props.header_len += 2; 1187 break; 1188 #endif 1189 } 1190 } 1191 1192 align = ALIGN(crypto_aead_blocksize(aead), 4); 1193 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1194 1195 error: 1196 return err; 1197 } 1198 1199 static int esp4_rcv_cb(struct sk_buff *skb, int err) 1200 { 1201 return 0; 1202 } 1203 1204 static const struct xfrm_type esp_type = 1205 { 1206 .description = "ESP4", 1207 .owner = THIS_MODULE, 1208 .proto = IPPROTO_ESP, 1209 .flags = XFRM_TYPE_REPLAY_PROT, 1210 .init_state = esp_init_state, 1211 .destructor = esp_destroy, 1212 .input = esp_input, 1213 .output = esp_output, 1214 }; 1215 1216 static struct xfrm4_protocol esp4_protocol = { 1217 .handler = xfrm4_rcv, 1218 .input_handler = xfrm_input, 1219 .cb_handler = esp4_rcv_cb, 1220 .err_handler = esp4_err, 1221 .priority = 0, 1222 }; 1223 1224 static int __init esp4_init(void) 1225 { 1226 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 1227 pr_info("%s: can't add xfrm type\n", __func__); 1228 return -EAGAIN; 1229 } 1230 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 1231 pr_info("%s: can't add protocol\n", __func__); 1232 xfrm_unregister_type(&esp_type, AF_INET); 1233 return -EAGAIN; 1234 } 1235 return 0; 1236 } 1237 1238 static void __exit esp4_fini(void) 1239 { 1240 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 1241 pr_info("%s: can't remove protocol\n", __func__); 1242 xfrm_unregister_type(&esp_type, AF_INET); 1243 } 1244 1245 module_init(esp4_init); 1246 module_exit(esp4_fini); 1247 MODULE_LICENSE("GPL"); 1248 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1249