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 void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto) 345 { 346 /* Fill padding... */ 347 if (tfclen) { 348 memset(tail, 0, tfclen); 349 tail += tfclen; 350 } 351 do { 352 int i; 353 for (i = 0; i < plen - 2; i++) 354 tail[i] = i + 1; 355 } while (0); 356 tail[plen - 2] = plen - 2; 357 tail[plen - 1] = proto; 358 } 359 360 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb, 361 int encap_type, 362 struct esp_info *esp, 363 __be16 sport, 364 __be16 dport) 365 { 366 struct udphdr *uh; 367 __be32 *udpdata32; 368 unsigned int len; 369 370 len = skb->len + esp->tailen - skb_transport_offset(skb); 371 if (len + sizeof(struct iphdr) > IP_MAX_MTU) 372 return ERR_PTR(-EMSGSIZE); 373 374 uh = (struct udphdr *)esp->esph; 375 uh->source = sport; 376 uh->dest = dport; 377 uh->len = htons(len); 378 uh->check = 0; 379 380 *skb_mac_header(skb) = IPPROTO_UDP; 381 382 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) { 383 udpdata32 = (__be32 *)(uh + 1); 384 udpdata32[0] = udpdata32[1] = 0; 385 return (struct ip_esp_hdr *)(udpdata32 + 2); 386 } 387 388 return (struct ip_esp_hdr *)(uh + 1); 389 } 390 391 #ifdef CONFIG_INET_ESPINTCP 392 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 393 struct sk_buff *skb, 394 struct esp_info *esp) 395 { 396 __be16 *lenp = (void *)esp->esph; 397 struct ip_esp_hdr *esph; 398 unsigned int len; 399 struct sock *sk; 400 401 len = skb->len + esp->tailen - skb_transport_offset(skb); 402 if (len > IP_MAX_MTU) 403 return ERR_PTR(-EMSGSIZE); 404 405 rcu_read_lock(); 406 sk = esp_find_tcp_sk(x); 407 rcu_read_unlock(); 408 409 if (IS_ERR(sk)) 410 return ERR_CAST(sk); 411 412 *lenp = htons(len); 413 esph = (struct ip_esp_hdr *)(lenp + 1); 414 415 return esph; 416 } 417 #else 418 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 419 struct sk_buff *skb, 420 struct esp_info *esp) 421 { 422 return ERR_PTR(-EOPNOTSUPP); 423 } 424 #endif 425 426 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb, 427 struct esp_info *esp) 428 { 429 struct xfrm_encap_tmpl *encap = x->encap; 430 struct ip_esp_hdr *esph; 431 __be16 sport, dport; 432 int encap_type; 433 434 spin_lock_bh(&x->lock); 435 sport = encap->encap_sport; 436 dport = encap->encap_dport; 437 encap_type = encap->encap_type; 438 spin_unlock_bh(&x->lock); 439 440 switch (encap_type) { 441 default: 442 case UDP_ENCAP_ESPINUDP: 443 case UDP_ENCAP_ESPINUDP_NON_IKE: 444 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport); 445 break; 446 case TCP_ENCAP_ESPINTCP: 447 esph = esp_output_tcp_encap(x, skb, esp); 448 break; 449 } 450 451 if (IS_ERR(esph)) 452 return PTR_ERR(esph); 453 454 esp->esph = esph; 455 456 return 0; 457 } 458 459 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 460 { 461 u8 *tail; 462 u8 *vaddr; 463 int nfrags; 464 int esph_offset; 465 struct page *page; 466 struct sk_buff *trailer; 467 int tailen = esp->tailen; 468 469 /* this is non-NULL only with TCP/UDP Encapsulation */ 470 if (x->encap) { 471 int err = esp_output_encap(x, skb, esp); 472 473 if (err < 0) 474 return err; 475 } 476 477 if (!skb_cloned(skb)) { 478 if (tailen <= skb_tailroom(skb)) { 479 nfrags = 1; 480 trailer = skb; 481 tail = skb_tail_pointer(trailer); 482 483 goto skip_cow; 484 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 485 && !skb_has_frag_list(skb)) { 486 int allocsize; 487 struct sock *sk = skb->sk; 488 struct page_frag *pfrag = &x->xfrag; 489 490 esp->inplace = false; 491 492 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 493 494 spin_lock_bh(&x->lock); 495 496 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 497 spin_unlock_bh(&x->lock); 498 goto cow; 499 } 500 501 page = pfrag->page; 502 get_page(page); 503 504 vaddr = kmap_atomic(page); 505 506 tail = vaddr + pfrag->offset; 507 508 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 509 510 kunmap_atomic(vaddr); 511 512 nfrags = skb_shinfo(skb)->nr_frags; 513 514 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 515 tailen); 516 skb_shinfo(skb)->nr_frags = ++nfrags; 517 518 pfrag->offset = pfrag->offset + allocsize; 519 520 spin_unlock_bh(&x->lock); 521 522 nfrags++; 523 524 skb->len += tailen; 525 skb->data_len += tailen; 526 skb->truesize += tailen; 527 if (sk && sk_fullsock(sk)) 528 refcount_add(tailen, &sk->sk_wmem_alloc); 529 530 goto out; 531 } 532 } 533 534 cow: 535 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 536 537 nfrags = skb_cow_data(skb, tailen, &trailer); 538 if (nfrags < 0) 539 goto out; 540 tail = skb_tail_pointer(trailer); 541 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 542 543 skip_cow: 544 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 545 pskb_put(skb, trailer, tailen); 546 547 out: 548 return nfrags; 549 } 550 EXPORT_SYMBOL_GPL(esp_output_head); 551 552 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 553 { 554 u8 *iv; 555 int alen; 556 void *tmp; 557 int ivlen; 558 int assoclen; 559 int extralen; 560 struct page *page; 561 struct ip_esp_hdr *esph; 562 struct crypto_aead *aead; 563 struct aead_request *req; 564 struct scatterlist *sg, *dsg; 565 struct esp_output_extra *extra; 566 int err = -ENOMEM; 567 568 assoclen = sizeof(struct ip_esp_hdr); 569 extralen = 0; 570 571 if (x->props.flags & XFRM_STATE_ESN) { 572 extralen += sizeof(*extra); 573 assoclen += sizeof(__be32); 574 } 575 576 aead = x->data; 577 alen = crypto_aead_authsize(aead); 578 ivlen = crypto_aead_ivsize(aead); 579 580 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 581 if (!tmp) 582 goto error; 583 584 extra = esp_tmp_extra(tmp); 585 iv = esp_tmp_iv(aead, tmp, extralen); 586 req = esp_tmp_req(aead, iv); 587 sg = esp_req_sg(aead, req); 588 589 if (esp->inplace) 590 dsg = sg; 591 else 592 dsg = &sg[esp->nfrags]; 593 594 esph = esp_output_set_extra(skb, x, esp->esph, extra); 595 esp->esph = esph; 596 597 sg_init_table(sg, esp->nfrags); 598 err = skb_to_sgvec(skb, sg, 599 (unsigned char *)esph - skb->data, 600 assoclen + ivlen + esp->clen + alen); 601 if (unlikely(err < 0)) 602 goto error_free; 603 604 if (!esp->inplace) { 605 int allocsize; 606 struct page_frag *pfrag = &x->xfrag; 607 608 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 609 610 spin_lock_bh(&x->lock); 611 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 612 spin_unlock_bh(&x->lock); 613 goto error_free; 614 } 615 616 skb_shinfo(skb)->nr_frags = 1; 617 618 page = pfrag->page; 619 get_page(page); 620 /* replace page frags in skb with new page */ 621 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 622 pfrag->offset = pfrag->offset + allocsize; 623 spin_unlock_bh(&x->lock); 624 625 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 626 err = skb_to_sgvec(skb, dsg, 627 (unsigned char *)esph - skb->data, 628 assoclen + ivlen + esp->clen + alen); 629 if (unlikely(err < 0)) 630 goto error_free; 631 } 632 633 if ((x->props.flags & XFRM_STATE_ESN)) 634 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 635 else 636 aead_request_set_callback(req, 0, esp_output_done, skb); 637 638 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 639 aead_request_set_ad(req, assoclen); 640 641 memset(iv, 0, ivlen); 642 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 643 min(ivlen, 8)); 644 645 ESP_SKB_CB(skb)->tmp = tmp; 646 err = crypto_aead_encrypt(req); 647 648 switch (err) { 649 case -EINPROGRESS: 650 goto error; 651 652 case -ENOSPC: 653 err = NET_XMIT_DROP; 654 break; 655 656 case 0: 657 if ((x->props.flags & XFRM_STATE_ESN)) 658 esp_output_restore_header(skb); 659 } 660 661 if (sg != dsg) 662 esp_ssg_unref(x, tmp); 663 664 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 665 err = esp_output_tail_tcp(x, skb); 666 667 error_free: 668 kfree(tmp); 669 error: 670 return err; 671 } 672 EXPORT_SYMBOL_GPL(esp_output_tail); 673 674 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 675 { 676 int alen; 677 int blksize; 678 struct ip_esp_hdr *esph; 679 struct crypto_aead *aead; 680 struct esp_info esp; 681 682 esp.inplace = true; 683 684 esp.proto = *skb_mac_header(skb); 685 *skb_mac_header(skb) = IPPROTO_ESP; 686 687 /* skb is pure payload to encrypt */ 688 689 aead = x->data; 690 alen = crypto_aead_authsize(aead); 691 692 esp.tfclen = 0; 693 if (x->tfcpad) { 694 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 695 u32 padto; 696 697 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 698 if (skb->len < padto) 699 esp.tfclen = padto - skb->len; 700 } 701 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 702 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 703 esp.plen = esp.clen - skb->len - esp.tfclen; 704 esp.tailen = esp.tfclen + esp.plen + alen; 705 706 esp.esph = ip_esp_hdr(skb); 707 708 esp.nfrags = esp_output_head(x, skb, &esp); 709 if (esp.nfrags < 0) 710 return esp.nfrags; 711 712 esph = esp.esph; 713 esph->spi = x->id.spi; 714 715 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 716 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 717 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 718 719 skb_push(skb, -skb_network_offset(skb)); 720 721 return esp_output_tail(x, skb, &esp); 722 } 723 724 static inline int esp_remove_trailer(struct sk_buff *skb) 725 { 726 struct xfrm_state *x = xfrm_input_state(skb); 727 struct xfrm_offload *xo = xfrm_offload(skb); 728 struct crypto_aead *aead = x->data; 729 int alen, hlen, elen; 730 int padlen, trimlen; 731 __wsum csumdiff; 732 u8 nexthdr[2]; 733 int ret; 734 735 alen = crypto_aead_authsize(aead); 736 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 737 elen = skb->len - hlen; 738 739 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) { 740 ret = xo->proto; 741 goto out; 742 } 743 744 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) 745 BUG(); 746 747 ret = -EINVAL; 748 padlen = nexthdr[0]; 749 if (padlen + 2 + alen >= elen) { 750 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 751 padlen + 2, elen - alen); 752 goto out; 753 } 754 755 trimlen = alen + padlen + 2; 756 if (skb->ip_summed == CHECKSUM_COMPLETE) { 757 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 758 skb->csum = csum_block_sub(skb->csum, csumdiff, 759 skb->len - trimlen); 760 } 761 pskb_trim(skb, skb->len - trimlen); 762 763 ret = nexthdr[1]; 764 765 out: 766 return ret; 767 } 768 769 int esp_input_done2(struct sk_buff *skb, int err) 770 { 771 const struct iphdr *iph; 772 struct xfrm_state *x = xfrm_input_state(skb); 773 struct xfrm_offload *xo = xfrm_offload(skb); 774 struct crypto_aead *aead = x->data; 775 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 776 int ihl; 777 778 if (!xo || (xo && !(xo->flags & CRYPTO_DONE))) 779 kfree(ESP_SKB_CB(skb)->tmp); 780 781 if (unlikely(err)) 782 goto out; 783 784 err = esp_remove_trailer(skb); 785 if (unlikely(err < 0)) 786 goto out; 787 788 iph = ip_hdr(skb); 789 ihl = iph->ihl * 4; 790 791 if (x->encap) { 792 struct xfrm_encap_tmpl *encap = x->encap; 793 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl); 794 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 795 __be16 source; 796 797 switch (x->encap->encap_type) { 798 case TCP_ENCAP_ESPINTCP: 799 source = th->source; 800 break; 801 case UDP_ENCAP_ESPINUDP: 802 case UDP_ENCAP_ESPINUDP_NON_IKE: 803 source = uh->source; 804 break; 805 default: 806 WARN_ON_ONCE(1); 807 err = -EINVAL; 808 goto out; 809 } 810 811 /* 812 * 1) if the NAT-T peer's IP or port changed then 813 * advertize the change to the keying daemon. 814 * This is an inbound SA, so just compare 815 * SRC ports. 816 */ 817 if (iph->saddr != x->props.saddr.a4 || 818 source != encap->encap_sport) { 819 xfrm_address_t ipaddr; 820 821 ipaddr.a4 = iph->saddr; 822 km_new_mapping(x, &ipaddr, source); 823 824 /* XXX: perhaps add an extra 825 * policy check here, to see 826 * if we should allow or 827 * reject a packet from a 828 * different source 829 * address/port. 830 */ 831 } 832 833 /* 834 * 2) ignore UDP/TCP checksums in case 835 * of NAT-T in Transport Mode, or 836 * perform other post-processing fixes 837 * as per draft-ietf-ipsec-udp-encaps-06, 838 * section 3.1.2 839 */ 840 if (x->props.mode == XFRM_MODE_TRANSPORT) 841 skb->ip_summed = CHECKSUM_UNNECESSARY; 842 } 843 844 skb_pull_rcsum(skb, hlen); 845 if (x->props.mode == XFRM_MODE_TUNNEL) 846 skb_reset_transport_header(skb); 847 else 848 skb_set_transport_header(skb, -ihl); 849 850 /* RFC4303: Drop dummy packets without any error */ 851 if (err == IPPROTO_NONE) 852 err = -EINVAL; 853 854 out: 855 return err; 856 } 857 EXPORT_SYMBOL_GPL(esp_input_done2); 858 859 static void esp_input_done(struct crypto_async_request *base, int err) 860 { 861 struct sk_buff *skb = base->data; 862 863 xfrm_input_resume(skb, esp_input_done2(skb, err)); 864 } 865 866 static void esp_input_restore_header(struct sk_buff *skb) 867 { 868 esp_restore_header(skb, 0); 869 __skb_pull(skb, 4); 870 } 871 872 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 873 { 874 struct xfrm_state *x = xfrm_input_state(skb); 875 struct ip_esp_hdr *esph; 876 877 /* For ESN we move the header forward by 4 bytes to 878 * accomodate the high bits. We will move it back after 879 * decryption. 880 */ 881 if ((x->props.flags & XFRM_STATE_ESN)) { 882 esph = skb_push(skb, 4); 883 *seqhi = esph->spi; 884 esph->spi = esph->seq_no; 885 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 886 } 887 } 888 889 static void esp_input_done_esn(struct crypto_async_request *base, int err) 890 { 891 struct sk_buff *skb = base->data; 892 893 esp_input_restore_header(skb); 894 esp_input_done(base, err); 895 } 896 897 /* 898 * Note: detecting truncated vs. non-truncated authentication data is very 899 * expensive, so we only support truncated data, which is the recommended 900 * and common case. 901 */ 902 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 903 { 904 struct crypto_aead *aead = x->data; 905 struct aead_request *req; 906 struct sk_buff *trailer; 907 int ivlen = crypto_aead_ivsize(aead); 908 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 909 int nfrags; 910 int assoclen; 911 int seqhilen; 912 __be32 *seqhi; 913 void *tmp; 914 u8 *iv; 915 struct scatterlist *sg; 916 int err = -EINVAL; 917 918 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) 919 goto out; 920 921 if (elen <= 0) 922 goto out; 923 924 assoclen = sizeof(struct ip_esp_hdr); 925 seqhilen = 0; 926 927 if (x->props.flags & XFRM_STATE_ESN) { 928 seqhilen += sizeof(__be32); 929 assoclen += seqhilen; 930 } 931 932 if (!skb_cloned(skb)) { 933 if (!skb_is_nonlinear(skb)) { 934 nfrags = 1; 935 936 goto skip_cow; 937 } else if (!skb_has_frag_list(skb)) { 938 nfrags = skb_shinfo(skb)->nr_frags; 939 nfrags++; 940 941 goto skip_cow; 942 } 943 } 944 945 err = skb_cow_data(skb, 0, &trailer); 946 if (err < 0) 947 goto out; 948 949 nfrags = err; 950 951 skip_cow: 952 err = -ENOMEM; 953 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 954 if (!tmp) 955 goto out; 956 957 ESP_SKB_CB(skb)->tmp = tmp; 958 seqhi = esp_tmp_extra(tmp); 959 iv = esp_tmp_iv(aead, tmp, seqhilen); 960 req = esp_tmp_req(aead, iv); 961 sg = esp_req_sg(aead, req); 962 963 esp_input_set_header(skb, seqhi); 964 965 sg_init_table(sg, nfrags); 966 err = skb_to_sgvec(skb, sg, 0, skb->len); 967 if (unlikely(err < 0)) { 968 kfree(tmp); 969 goto out; 970 } 971 972 skb->ip_summed = CHECKSUM_NONE; 973 974 if ((x->props.flags & XFRM_STATE_ESN)) 975 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 976 else 977 aead_request_set_callback(req, 0, esp_input_done, skb); 978 979 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 980 aead_request_set_ad(req, assoclen); 981 982 err = crypto_aead_decrypt(req); 983 if (err == -EINPROGRESS) 984 goto out; 985 986 if ((x->props.flags & XFRM_STATE_ESN)) 987 esp_input_restore_header(skb); 988 989 err = esp_input_done2(skb, err); 990 991 out: 992 return err; 993 } 994 995 static int esp4_err(struct sk_buff *skb, u32 info) 996 { 997 struct net *net = dev_net(skb->dev); 998 const struct iphdr *iph = (const struct iphdr *)skb->data; 999 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 1000 struct xfrm_state *x; 1001 1002 switch (icmp_hdr(skb)->type) { 1003 case ICMP_DEST_UNREACH: 1004 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 1005 return 0; 1006 case ICMP_REDIRECT: 1007 break; 1008 default: 1009 return 0; 1010 } 1011 1012 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 1013 esph->spi, IPPROTO_ESP, AF_INET); 1014 if (!x) 1015 return 0; 1016 1017 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 1018 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP); 1019 else 1020 ipv4_redirect(skb, net, 0, IPPROTO_ESP); 1021 xfrm_state_put(x); 1022 1023 return 0; 1024 } 1025 1026 static void esp_destroy(struct xfrm_state *x) 1027 { 1028 struct crypto_aead *aead = x->data; 1029 1030 if (!aead) 1031 return; 1032 1033 crypto_free_aead(aead); 1034 } 1035 1036 static int esp_init_aead(struct xfrm_state *x) 1037 { 1038 char aead_name[CRYPTO_MAX_ALG_NAME]; 1039 struct crypto_aead *aead; 1040 int err; 1041 1042 err = -ENAMETOOLONG; 1043 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 1044 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) 1045 goto error; 1046 1047 aead = crypto_alloc_aead(aead_name, 0, 0); 1048 err = PTR_ERR(aead); 1049 if (IS_ERR(aead)) 1050 goto error; 1051 1052 x->data = aead; 1053 1054 err = crypto_aead_setkey(aead, x->aead->alg_key, 1055 (x->aead->alg_key_len + 7) / 8); 1056 if (err) 1057 goto error; 1058 1059 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1060 if (err) 1061 goto error; 1062 1063 error: 1064 return err; 1065 } 1066 1067 static int esp_init_authenc(struct xfrm_state *x) 1068 { 1069 struct crypto_aead *aead; 1070 struct crypto_authenc_key_param *param; 1071 struct rtattr *rta; 1072 char *key; 1073 char *p; 1074 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1075 unsigned int keylen; 1076 int err; 1077 1078 err = -EINVAL; 1079 if (!x->ealg) 1080 goto error; 1081 1082 err = -ENAMETOOLONG; 1083 1084 if ((x->props.flags & XFRM_STATE_ESN)) { 1085 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1086 "%s%sauthencesn(%s,%s)%s", 1087 x->geniv ?: "", x->geniv ? "(" : "", 1088 x->aalg ? x->aalg->alg_name : "digest_null", 1089 x->ealg->alg_name, 1090 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1091 goto error; 1092 } else { 1093 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1094 "%s%sauthenc(%s,%s)%s", 1095 x->geniv ?: "", x->geniv ? "(" : "", 1096 x->aalg ? x->aalg->alg_name : "digest_null", 1097 x->ealg->alg_name, 1098 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) 1099 goto error; 1100 } 1101 1102 aead = crypto_alloc_aead(authenc_name, 0, 0); 1103 err = PTR_ERR(aead); 1104 if (IS_ERR(aead)) 1105 goto error; 1106 1107 x->data = aead; 1108 1109 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1110 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1111 err = -ENOMEM; 1112 key = kmalloc(keylen, GFP_KERNEL); 1113 if (!key) 1114 goto error; 1115 1116 p = key; 1117 rta = (void *)p; 1118 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1119 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1120 param = RTA_DATA(rta); 1121 p += RTA_SPACE(sizeof(*param)); 1122 1123 if (x->aalg) { 1124 struct xfrm_algo_desc *aalg_desc; 1125 1126 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1127 p += (x->aalg->alg_key_len + 7) / 8; 1128 1129 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1130 BUG_ON(!aalg_desc); 1131 1132 err = -EINVAL; 1133 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1134 crypto_aead_authsize(aead)) { 1135 pr_info("ESP: %s digestsize %u != %hu\n", 1136 x->aalg->alg_name, 1137 crypto_aead_authsize(aead), 1138 aalg_desc->uinfo.auth.icv_fullbits / 8); 1139 goto free_key; 1140 } 1141 1142 err = crypto_aead_setauthsize( 1143 aead, x->aalg->alg_trunc_len / 8); 1144 if (err) 1145 goto free_key; 1146 } 1147 1148 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1149 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1150 1151 err = crypto_aead_setkey(aead, key, keylen); 1152 1153 free_key: 1154 kfree(key); 1155 1156 error: 1157 return err; 1158 } 1159 1160 static int esp_init_state(struct xfrm_state *x) 1161 { 1162 struct crypto_aead *aead; 1163 u32 align; 1164 int err; 1165 1166 x->data = NULL; 1167 1168 if (x->aead) 1169 err = esp_init_aead(x); 1170 else 1171 err = esp_init_authenc(x); 1172 1173 if (err) 1174 goto error; 1175 1176 aead = x->data; 1177 1178 x->props.header_len = sizeof(struct ip_esp_hdr) + 1179 crypto_aead_ivsize(aead); 1180 if (x->props.mode == XFRM_MODE_TUNNEL) 1181 x->props.header_len += sizeof(struct iphdr); 1182 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 1183 x->props.header_len += IPV4_BEET_PHMAXLEN; 1184 if (x->encap) { 1185 struct xfrm_encap_tmpl *encap = x->encap; 1186 1187 switch (encap->encap_type) { 1188 default: 1189 err = -EINVAL; 1190 goto error; 1191 case UDP_ENCAP_ESPINUDP: 1192 x->props.header_len += sizeof(struct udphdr); 1193 break; 1194 case UDP_ENCAP_ESPINUDP_NON_IKE: 1195 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); 1196 break; 1197 #ifdef CONFIG_INET_ESPINTCP 1198 case TCP_ENCAP_ESPINTCP: 1199 /* only the length field, TCP encap is done by 1200 * the socket 1201 */ 1202 x->props.header_len += 2; 1203 break; 1204 #endif 1205 } 1206 } 1207 1208 align = ALIGN(crypto_aead_blocksize(aead), 4); 1209 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1210 1211 error: 1212 return err; 1213 } 1214 1215 static int esp4_rcv_cb(struct sk_buff *skb, int err) 1216 { 1217 return 0; 1218 } 1219 1220 static const struct xfrm_type esp_type = 1221 { 1222 .description = "ESP4", 1223 .owner = THIS_MODULE, 1224 .proto = IPPROTO_ESP, 1225 .flags = XFRM_TYPE_REPLAY_PROT, 1226 .init_state = esp_init_state, 1227 .destructor = esp_destroy, 1228 .input = esp_input, 1229 .output = esp_output, 1230 }; 1231 1232 static struct xfrm4_protocol esp4_protocol = { 1233 .handler = xfrm4_rcv, 1234 .input_handler = xfrm_input, 1235 .cb_handler = esp4_rcv_cb, 1236 .err_handler = esp4_err, 1237 .priority = 0, 1238 }; 1239 1240 static int __init esp4_init(void) 1241 { 1242 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 1243 pr_info("%s: can't add xfrm type\n", __func__); 1244 return -EAGAIN; 1245 } 1246 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 1247 pr_info("%s: can't add protocol\n", __func__); 1248 xfrm_unregister_type(&esp_type, AF_INET); 1249 return -EAGAIN; 1250 } 1251 return 0; 1252 } 1253 1254 static void __exit esp4_fini(void) 1255 { 1256 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 1257 pr_info("%s: can't remove protocol\n", __func__); 1258 xfrm_unregister_type(&esp_type, AF_INET); 1259 } 1260 1261 module_init(esp4_init); 1262 module_exit(esp4_fini); 1263 MODULE_LICENSE("GPL"); 1264 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1265