1 // SPDX-License-Identifier: GPL-2.0-only 2 #define pr_fmt(fmt) "IPsec: " fmt 3 4 #include <crypto/aead.h> 5 #include <crypto/authenc.h> 6 #include <linux/err.h> 7 #include <linux/module.h> 8 #include <net/ip.h> 9 #include <net/xfrm.h> 10 #include <net/esp.h> 11 #include <linux/scatterlist.h> 12 #include <linux/kernel.h> 13 #include <linux/pfkeyv2.h> 14 #include <linux/rtnetlink.h> 15 #include <linux/slab.h> 16 #include <linux/spinlock.h> 17 #include <linux/in6.h> 18 #include <net/icmp.h> 19 #include <net/protocol.h> 20 #include <net/udp.h> 21 #include <net/tcp.h> 22 #include <net/espintcp.h> 23 #include <linux/skbuff_ref.h> 24 25 #include <linux/highmem.h> 26 27 struct esp_skb_cb { 28 struct xfrm_skb_cb xfrm; 29 void *tmp; 30 }; 31 32 struct esp_output_extra { 33 __be32 seqhi; 34 u32 esphoff; 35 }; 36 37 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0])) 38 39 /* 40 * Allocate an AEAD request structure with extra space for SG and IV. 41 * 42 * For alignment considerations the IV is placed at the front, followed 43 * by the request and finally the SG list. 44 * 45 * TODO: Use spare space in skb for this where possible. 46 */ 47 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen) 48 { 49 unsigned int len; 50 51 len = extralen; 52 53 len += crypto_aead_ivsize(aead); 54 55 if (len) { 56 len += crypto_aead_alignmask(aead) & 57 ~(crypto_tfm_ctx_alignment() - 1); 58 len = ALIGN(len, crypto_tfm_ctx_alignment()); 59 } 60 61 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead); 62 len = ALIGN(len, __alignof__(struct scatterlist)); 63 64 len += sizeof(struct scatterlist) * nfrags; 65 66 return kmalloc(len, GFP_ATOMIC); 67 } 68 69 static inline void *esp_tmp_extra(void *tmp) 70 { 71 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra)); 72 } 73 74 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen) 75 { 76 return crypto_aead_ivsize(aead) ? 77 PTR_ALIGN((u8 *)tmp + extralen, 78 crypto_aead_alignmask(aead) + 1) : tmp + extralen; 79 } 80 81 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv) 82 { 83 struct aead_request *req; 84 85 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead), 86 crypto_tfm_ctx_alignment()); 87 aead_request_set_tfm(req, aead); 88 return req; 89 } 90 91 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead, 92 struct aead_request *req) 93 { 94 return (void *)ALIGN((unsigned long)(req + 1) + 95 crypto_aead_reqsize(aead), 96 __alignof__(struct scatterlist)); 97 } 98 99 static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb, bool already_unref) 100 { 101 struct crypto_aead *aead = x->data; 102 int extralen = 0; 103 u8 *iv; 104 struct aead_request *req; 105 struct scatterlist *sg; 106 107 if (x->props.flags & XFRM_STATE_ESN) 108 extralen += sizeof(struct esp_output_extra); 109 110 iv = esp_tmp_iv(aead, tmp, extralen); 111 req = esp_tmp_req(aead, iv); 112 113 /* Unref skb_frag_pages in the src scatterlist if necessary. 114 * Skip the first sg which comes from skb->data. 115 */ 116 if (already_unref || req->src != req->dst) { 117 struct scatterlist *src = already_unref ? esp_req_sg(aead, req) : req->src; 118 119 for (sg = sg_next(src); sg; sg = sg_next(sg)) 120 skb_page_unref(page_to_netmem(sg_page(sg)), 121 skb->pp_recycle); 122 } 123 } 124 125 #ifdef CONFIG_INET_ESPINTCP 126 static struct sock *esp_find_tcp_sk(struct xfrm_state *x) 127 { 128 struct xfrm_encap_tmpl *encap = x->encap; 129 struct net *net = xs_net(x); 130 __be16 sport, dport; 131 struct sock *sk; 132 133 spin_lock_bh(&x->lock); 134 sport = encap->encap_sport; 135 dport = encap->encap_dport; 136 spin_unlock_bh(&x->lock); 137 138 sk = inet_lookup_established(net, x->id.daddr.a4, dport, 139 x->props.saddr.a4, sport, 0); 140 if (!sk) 141 return ERR_PTR(-ENOENT); 142 143 if (!tcp_is_ulp_esp(sk)) { 144 sock_put(sk); 145 return ERR_PTR(-EINVAL); 146 } 147 148 return sk; 149 } 150 151 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb) 152 { 153 struct sock *sk; 154 int err; 155 156 rcu_read_lock(); 157 158 sk = esp_find_tcp_sk(x); 159 err = PTR_ERR_OR_ZERO(sk); 160 if (err) { 161 kfree_skb(skb); 162 goto out; 163 } 164 165 bh_lock_sock(sk); 166 if (sock_owned_by_user(sk)) 167 err = espintcp_queue_out(sk, skb); 168 else 169 err = espintcp_push_skb(sk, skb); 170 bh_unlock_sock(sk); 171 172 sock_put(sk); 173 174 out: 175 rcu_read_unlock(); 176 return err; 177 } 178 179 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk, 180 struct sk_buff *skb) 181 { 182 struct dst_entry *dst = skb_dst(skb); 183 struct xfrm_state *x = dst->xfrm; 184 185 return esp_output_tcp_finish(x, skb); 186 } 187 188 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 189 { 190 int err; 191 192 local_bh_disable(); 193 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb); 194 local_bh_enable(); 195 196 /* EINPROGRESS just happens to do the right thing. It 197 * actually means that the skb has been consumed and 198 * isn't coming back. 199 */ 200 return err ?: -EINPROGRESS; 201 } 202 #else 203 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb) 204 { 205 WARN_ON(1); 206 return -EOPNOTSUPP; 207 } 208 #endif 209 210 static void esp_output_done(void *data, int err) 211 { 212 struct sk_buff *skb = data; 213 struct xfrm_offload *xo = xfrm_offload(skb); 214 void *tmp; 215 struct xfrm_state *x; 216 217 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 218 struct sec_path *sp = skb_sec_path(skb); 219 220 x = sp->xvec[sp->len - 1]; 221 } else { 222 x = skb_dst(skb)->xfrm; 223 } 224 225 tmp = ESP_SKB_CB(skb)->tmp; 226 esp_ssg_unref(x, tmp, skb, false); 227 kfree(tmp); 228 229 if (xo && (xo->flags & XFRM_DEV_RESUME)) { 230 if (err) { 231 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR); 232 kfree_skb(skb); 233 return; 234 } 235 236 skb_push(skb, skb->data - skb_mac_header(skb)); 237 secpath_reset(skb); 238 xfrm_dev_resume(skb); 239 } else { 240 if (!err && 241 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) { 242 err = esp_output_tail_tcp(x, skb); 243 if (err != -EINPROGRESS) 244 kfree_skb(skb); 245 } else { 246 xfrm_output_resume(skb_to_full_sk(skb), skb, err); 247 } 248 } 249 } 250 251 /* Move ESP header back into place. */ 252 static void esp_restore_header(struct sk_buff *skb, unsigned int offset) 253 { 254 struct ip_esp_hdr *esph = (void *)(skb->data + offset); 255 void *tmp = ESP_SKB_CB(skb)->tmp; 256 __be32 *seqhi = esp_tmp_extra(tmp); 257 258 esph->seq_no = esph->spi; 259 esph->spi = *seqhi; 260 } 261 262 static void esp_output_restore_header(struct sk_buff *skb) 263 { 264 void *tmp = ESP_SKB_CB(skb)->tmp; 265 struct esp_output_extra *extra = esp_tmp_extra(tmp); 266 267 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff - 268 sizeof(__be32)); 269 } 270 271 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb, 272 struct xfrm_state *x, 273 struct ip_esp_hdr *esph, 274 struct esp_output_extra *extra) 275 { 276 /* For ESN we move the header forward by 4 bytes to 277 * accommodate the high bits. We will move it back after 278 * encryption. 279 */ 280 if ((x->props.flags & XFRM_STATE_ESN)) { 281 __u32 seqhi; 282 struct xfrm_offload *xo = xfrm_offload(skb); 283 284 if (xo) 285 seqhi = xo->seq.hi; 286 else 287 seqhi = XFRM_SKB_CB(skb)->seq.output.hi; 288 289 extra->esphoff = (unsigned char *)esph - 290 skb_transport_header(skb); 291 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4); 292 extra->seqhi = esph->spi; 293 esph->seq_no = htonl(seqhi); 294 } 295 296 esph->spi = x->id.spi; 297 298 return esph; 299 } 300 301 static void esp_output_done_esn(void *data, int err) 302 { 303 struct sk_buff *skb = data; 304 305 esp_output_restore_header(skb); 306 esp_output_done(data, err); 307 } 308 309 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb, 310 int encap_type, 311 struct esp_info *esp, 312 __be16 sport, 313 __be16 dport) 314 { 315 struct udphdr *uh; 316 unsigned int len; 317 struct xfrm_offload *xo = xfrm_offload(skb); 318 319 len = skb->len + esp->tailen - skb_transport_offset(skb); 320 if (len + sizeof(struct iphdr) > IP_MAX_MTU) 321 return ERR_PTR(-EMSGSIZE); 322 323 uh = (struct udphdr *)esp->esph; 324 uh->source = sport; 325 uh->dest = dport; 326 udp_set_len_short(uh, len); 327 uh->check = 0; 328 329 /* For IPv4 ESP with UDP encapsulation, if xo is not null, the skb is in the crypto offload 330 * data path, which means that esp_output_udp_encap is called outside of the XFRM stack. 331 * In this case, the mac header doesn't point to the IPv4 protocol field, so don't set it. 332 */ 333 if (!xo || encap_type != UDP_ENCAP_ESPINUDP) 334 *skb_mac_header(skb) = IPPROTO_UDP; 335 336 return (struct ip_esp_hdr *)(uh + 1); 337 } 338 339 #ifdef CONFIG_INET_ESPINTCP 340 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 341 struct sk_buff *skb, 342 struct esp_info *esp) 343 { 344 __be16 *lenp = (void *)esp->esph; 345 struct ip_esp_hdr *esph; 346 unsigned int len; 347 struct sock *sk; 348 349 len = skb->len + esp->tailen - skb_transport_offset(skb); 350 if (len > IP_MAX_MTU) 351 return ERR_PTR(-EMSGSIZE); 352 353 rcu_read_lock(); 354 sk = esp_find_tcp_sk(x); 355 rcu_read_unlock(); 356 357 if (IS_ERR(sk)) 358 return ERR_CAST(sk); 359 360 sock_put(sk); 361 362 *lenp = htons(len); 363 esph = (struct ip_esp_hdr *)(lenp + 1); 364 365 return esph; 366 } 367 #else 368 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x, 369 struct sk_buff *skb, 370 struct esp_info *esp) 371 { 372 return ERR_PTR(-EOPNOTSUPP); 373 } 374 #endif 375 376 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb, 377 struct esp_info *esp) 378 { 379 struct xfrm_encap_tmpl *encap = x->encap; 380 struct ip_esp_hdr *esph; 381 __be16 sport, dport; 382 int encap_type; 383 384 spin_lock_bh(&x->lock); 385 sport = encap->encap_sport; 386 dport = encap->encap_dport; 387 encap_type = encap->encap_type; 388 spin_unlock_bh(&x->lock); 389 390 switch (encap_type) { 391 default: 392 case UDP_ENCAP_ESPINUDP: 393 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport); 394 break; 395 case TCP_ENCAP_ESPINTCP: 396 esph = esp_output_tcp_encap(x, skb, esp); 397 break; 398 } 399 400 if (IS_ERR(esph)) 401 return PTR_ERR(esph); 402 403 esp->esph = esph; 404 405 return 0; 406 } 407 408 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 409 { 410 u8 *tail; 411 int nfrags; 412 int esph_offset; 413 struct page *page; 414 struct sk_buff *trailer; 415 int tailen = esp->tailen; 416 417 /* this is non-NULL only with TCP/UDP Encapsulation */ 418 if (x->encap) { 419 int err = esp_output_encap(x, skb, esp); 420 421 if (err < 0) 422 return err; 423 } 424 425 if (ALIGN(skb->data_len + tailen, L1_CACHE_BYTES) > 426 PAGE_SIZE) 427 goto cow; 428 429 if (!skb_cloned(skb)) { 430 if (tailen <= skb_tailroom(skb)) { 431 nfrags = 1; 432 trailer = skb; 433 tail = skb_tail_pointer(trailer); 434 435 goto skip_cow; 436 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS) 437 && !skb_has_frag_list(skb)) { 438 int allocsize; 439 struct sock *sk = skb->sk; 440 struct page_frag *pfrag = &x->xfrag; 441 442 esp->inplace = false; 443 444 /* Take real page refs and clear SKBFL_MANAGED_FRAG_REFS before 445 * we mutate the frag array, so the per-frag unref stays balanced 446 * for zerocopy managed frags (see __ip_append_data()). 447 */ 448 skb_zcopy_downgrade_managed(skb); 449 450 allocsize = ALIGN(tailen, L1_CACHE_BYTES); 451 452 spin_lock_bh(&x->lock); 453 454 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 455 spin_unlock_bh(&x->lock); 456 goto cow; 457 } 458 459 page = pfrag->page; 460 get_page(page); 461 462 tail = page_address(page) + pfrag->offset; 463 464 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 465 466 nfrags = skb_shinfo(skb)->nr_frags; 467 468 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset, 469 tailen); 470 skb_shinfo(skb)->nr_frags = ++nfrags; 471 472 pfrag->offset = pfrag->offset + allocsize; 473 474 spin_unlock_bh(&x->lock); 475 476 nfrags++; 477 478 skb_len_add(skb, tailen); 479 if (sk && sk_fullsock(sk)) 480 refcount_add(tailen, &sk->sk_wmem_alloc); 481 482 goto out; 483 } 484 } 485 486 cow: 487 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb); 488 489 nfrags = skb_cow_data(skb, tailen, &trailer); 490 if (nfrags < 0) 491 goto out; 492 tail = skb_tail_pointer(trailer); 493 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset); 494 495 skip_cow: 496 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto); 497 pskb_put(skb, trailer, tailen); 498 499 out: 500 return nfrags; 501 } 502 EXPORT_SYMBOL_GPL(esp_output_head); 503 504 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp) 505 { 506 u8 *iv; 507 int alen; 508 void *tmp; 509 int ivlen; 510 int assoclen; 511 int extralen; 512 struct page *page; 513 struct ip_esp_hdr *esph; 514 struct crypto_aead *aead; 515 struct aead_request *req; 516 struct scatterlist *sg, *dsg; 517 struct esp_output_extra *extra; 518 int err = -ENOMEM; 519 520 assoclen = sizeof(struct ip_esp_hdr); 521 extralen = 0; 522 523 if (x->props.flags & XFRM_STATE_ESN) { 524 extralen += sizeof(*extra); 525 assoclen += sizeof(__be32); 526 } 527 528 aead = x->data; 529 alen = crypto_aead_authsize(aead); 530 ivlen = crypto_aead_ivsize(aead); 531 532 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen); 533 if (!tmp) 534 goto error; 535 536 extra = esp_tmp_extra(tmp); 537 iv = esp_tmp_iv(aead, tmp, extralen); 538 req = esp_tmp_req(aead, iv); 539 sg = esp_req_sg(aead, req); 540 541 if (esp->inplace) 542 dsg = sg; 543 else 544 dsg = &sg[esp->nfrags]; 545 546 esph = esp_output_set_extra(skb, x, esp->esph, extra); 547 esp->esph = esph; 548 549 sg_init_table(sg, esp->nfrags); 550 err = skb_to_sgvec(skb, sg, 551 (unsigned char *)esph - skb->data, 552 assoclen + ivlen + esp->clen + alen); 553 if (unlikely(err < 0)) 554 goto error_free; 555 556 if (!esp->inplace) { 557 int allocsize; 558 struct page_frag *pfrag = &x->xfrag; 559 560 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES); 561 562 spin_lock_bh(&x->lock); 563 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) { 564 spin_unlock_bh(&x->lock); 565 goto error_free; 566 } 567 568 skb_shinfo(skb)->nr_frags = 1; 569 570 page = pfrag->page; 571 get_page(page); 572 /* replace page frags in skb with new page */ 573 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len); 574 pfrag->offset = pfrag->offset + allocsize; 575 spin_unlock_bh(&x->lock); 576 577 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1); 578 err = skb_to_sgvec(skb, dsg, 579 (unsigned char *)esph - skb->data, 580 assoclen + ivlen + esp->clen + alen); 581 if (unlikely(err < 0)) { 582 esp_ssg_unref(x, tmp, skb, true); 583 goto error_free; 584 } 585 } 586 587 if ((x->props.flags & XFRM_STATE_ESN)) 588 aead_request_set_callback(req, 0, esp_output_done_esn, skb); 589 else 590 aead_request_set_callback(req, 0, esp_output_done, skb); 591 592 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv); 593 aead_request_set_ad(req, assoclen); 594 595 memset(iv, 0, ivlen); 596 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8), 597 min(ivlen, 8)); 598 599 ESP_SKB_CB(skb)->tmp = tmp; 600 err = crypto_aead_encrypt(req); 601 602 switch (err) { 603 case -EINPROGRESS: 604 goto error; 605 606 case -ENOSPC: 607 err = NET_XMIT_DROP; 608 break; 609 610 case 0: 611 if ((x->props.flags & XFRM_STATE_ESN)) 612 esp_output_restore_header(skb); 613 } 614 615 if (sg != dsg) 616 esp_ssg_unref(x, tmp, skb, false); 617 618 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) 619 err = esp_output_tail_tcp(x, skb); 620 621 error_free: 622 kfree(tmp); 623 error: 624 return err; 625 } 626 EXPORT_SYMBOL_GPL(esp_output_tail); 627 628 static int esp_output(struct xfrm_state *x, struct sk_buff *skb) 629 { 630 int alen; 631 int blksize; 632 struct ip_esp_hdr *esph; 633 struct crypto_aead *aead; 634 struct esp_info esp; 635 636 esp.inplace = true; 637 638 esp.proto = *skb_mac_header(skb); 639 *skb_mac_header(skb) = IPPROTO_ESP; 640 641 /* skb is pure payload to encrypt */ 642 643 aead = x->data; 644 alen = crypto_aead_authsize(aead); 645 646 esp.tfclen = 0; 647 if (x->tfcpad) { 648 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 649 u32 padto; 650 651 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached)); 652 if (skb->len < padto) 653 esp.tfclen = padto - skb->len; 654 } 655 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 656 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize); 657 esp.plen = esp.clen - skb->len - esp.tfclen; 658 esp.tailen = esp.tfclen + esp.plen + alen; 659 660 esp.esph = ip_esp_hdr(skb); 661 662 esp.nfrags = esp_output_head(x, skb, &esp); 663 if (esp.nfrags < 0) 664 return esp.nfrags; 665 666 esph = esp.esph; 667 esph->spi = x->id.spi; 668 669 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 670 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low + 671 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32)); 672 673 skb_push(skb, -skb_network_offset(skb)); 674 675 return esp_output_tail(x, skb, &esp); 676 } 677 678 static inline int esp_remove_trailer(struct sk_buff *skb) 679 { 680 struct xfrm_state *x = xfrm_input_state(skb); 681 struct crypto_aead *aead = x->data; 682 int alen, hlen, elen; 683 int padlen, trimlen; 684 __wsum csumdiff; 685 u8 nexthdr[2]; 686 int ret; 687 688 alen = crypto_aead_authsize(aead); 689 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 690 elen = skb->len - hlen; 691 692 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) 693 BUG(); 694 695 ret = -EINVAL; 696 padlen = nexthdr[0]; 697 if (padlen + 2 + alen >= elen) { 698 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n", 699 padlen + 2, elen - alen); 700 goto out; 701 } 702 703 trimlen = alen + padlen + 2; 704 if (skb->ip_summed == CHECKSUM_COMPLETE) { 705 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0); 706 skb->csum = csum_block_sub(skb->csum, csumdiff, 707 skb->len - trimlen); 708 } 709 ret = pskb_trim(skb, skb->len - trimlen); 710 if (unlikely(ret)) 711 return ret; 712 713 ret = nexthdr[1]; 714 715 out: 716 return ret; 717 } 718 719 int esp_input_done2(struct sk_buff *skb, int err) 720 { 721 const struct iphdr *iph; 722 struct xfrm_state *x = xfrm_input_state(skb); 723 struct xfrm_offload *xo = xfrm_offload(skb); 724 struct crypto_aead *aead = x->data; 725 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 726 int ihl; 727 728 if (!xo || !(xo->flags & CRYPTO_DONE)) 729 kfree(ESP_SKB_CB(skb)->tmp); 730 731 if (unlikely(err)) 732 goto out; 733 734 err = esp_remove_trailer(skb); 735 if (unlikely(err < 0)) 736 goto out; 737 738 iph = ip_hdr(skb); 739 ihl = iph->ihl * 4; 740 741 if (x->encap) { 742 struct xfrm_encap_tmpl *encap = x->encap; 743 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl); 744 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); 745 __be16 source; 746 747 switch (x->encap->encap_type) { 748 case TCP_ENCAP_ESPINTCP: 749 source = th->source; 750 break; 751 case UDP_ENCAP_ESPINUDP: 752 source = uh->source; 753 break; 754 default: 755 WARN_ON_ONCE(1); 756 err = -EINVAL; 757 goto out; 758 } 759 760 /* 761 * 1) if the NAT-T peer's IP or port changed then 762 * advertise the change to the keying daemon. 763 * This is an inbound SA, so just compare 764 * SRC ports. 765 */ 766 if (iph->saddr != x->props.saddr.a4 || 767 source != encap->encap_sport) { 768 xfrm_address_t ipaddr; 769 770 ipaddr.a4 = iph->saddr; 771 km_new_mapping(x, &ipaddr, source); 772 773 /* XXX: perhaps add an extra 774 * policy check here, to see 775 * if we should allow or 776 * reject a packet from a 777 * different source 778 * address/port. 779 */ 780 } 781 782 /* 783 * 2) ignore UDP/TCP checksums in case 784 * of NAT-T in Transport Mode, or 785 * perform other post-processing fixes 786 * as per draft-ietf-ipsec-udp-encaps-06, 787 * section 3.1.2 788 */ 789 if (x->props.mode == XFRM_MODE_TRANSPORT) 790 skb->ip_summed = CHECKSUM_UNNECESSARY; 791 } 792 793 skb_pull_rcsum(skb, hlen); 794 if (x->props.mode == XFRM_MODE_TUNNEL || 795 x->props.mode == XFRM_MODE_IPTFS) 796 skb_reset_transport_header(skb); 797 else 798 skb_set_transport_header(skb, -ihl); 799 800 /* RFC4303: Drop dummy packets without any error */ 801 if (err == IPPROTO_NONE) 802 err = -EINVAL; 803 804 out: 805 return err; 806 } 807 EXPORT_SYMBOL_GPL(esp_input_done2); 808 809 static void esp_input_done(void *data, int err) 810 { 811 struct sk_buff *skb = data; 812 813 xfrm_input_resume(skb, esp_input_done2(skb, err)); 814 } 815 816 static void esp_input_restore_header(struct sk_buff *skb) 817 { 818 esp_restore_header(skb, 0); 819 __skb_pull(skb, 4); 820 } 821 822 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi) 823 { 824 struct xfrm_state *x = xfrm_input_state(skb); 825 struct ip_esp_hdr *esph; 826 827 /* For ESN we move the header forward by 4 bytes to 828 * accommodate the high bits. We will move it back after 829 * decryption. 830 */ 831 if ((x->props.flags & XFRM_STATE_ESN)) { 832 esph = skb_push(skb, 4); 833 *seqhi = esph->spi; 834 esph->spi = esph->seq_no; 835 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi; 836 } 837 } 838 839 static void esp_input_done_esn(void *data, int err) 840 { 841 struct sk_buff *skb = data; 842 843 esp_input_restore_header(skb); 844 esp_input_done(data, err); 845 } 846 847 /* 848 * Note: detecting truncated vs. non-truncated authentication data is very 849 * expensive, so we only support truncated data, which is the recommended 850 * and common case. 851 */ 852 static int esp_input(struct xfrm_state *x, struct sk_buff *skb) 853 { 854 struct crypto_aead *aead = x->data; 855 struct aead_request *req; 856 struct sk_buff *trailer; 857 int ivlen = crypto_aead_ivsize(aead); 858 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen; 859 int nfrags; 860 int assoclen; 861 int seqhilen; 862 __be32 *seqhi; 863 void *tmp; 864 u8 *iv; 865 struct scatterlist *sg; 866 int err = -EINVAL; 867 868 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) 869 goto out; 870 871 if (elen <= 0) 872 goto out; 873 874 assoclen = sizeof(struct ip_esp_hdr); 875 seqhilen = 0; 876 877 if (x->props.flags & XFRM_STATE_ESN) { 878 seqhilen += sizeof(__be32); 879 assoclen += seqhilen; 880 } 881 882 if (!skb_cloned(skb)) { 883 if (!skb_is_nonlinear(skb)) { 884 nfrags = 1; 885 886 goto skip_cow; 887 } else if (!skb_has_frag_list(skb) && 888 !skb_has_shared_frag(skb)) { 889 nfrags = skb_shinfo(skb)->nr_frags; 890 nfrags++; 891 892 goto skip_cow; 893 } 894 } 895 896 err = skb_cow_data(skb, 0, &trailer); 897 if (err < 0) 898 goto out; 899 900 nfrags = err; 901 902 skip_cow: 903 err = -ENOMEM; 904 tmp = esp_alloc_tmp(aead, nfrags, seqhilen); 905 if (!tmp) 906 goto out; 907 908 ESP_SKB_CB(skb)->tmp = tmp; 909 seqhi = esp_tmp_extra(tmp); 910 iv = esp_tmp_iv(aead, tmp, seqhilen); 911 req = esp_tmp_req(aead, iv); 912 sg = esp_req_sg(aead, req); 913 914 esp_input_set_header(skb, seqhi); 915 916 sg_init_table(sg, nfrags); 917 err = skb_to_sgvec(skb, sg, 0, skb->len); 918 if (unlikely(err < 0)) { 919 kfree(tmp); 920 goto out; 921 } 922 923 skb->ip_summed = CHECKSUM_NONE; 924 925 if ((x->props.flags & XFRM_STATE_ESN)) 926 aead_request_set_callback(req, 0, esp_input_done_esn, skb); 927 else 928 aead_request_set_callback(req, 0, esp_input_done, skb); 929 930 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv); 931 aead_request_set_ad(req, assoclen); 932 933 err = crypto_aead_decrypt(req); 934 if (err == -EINPROGRESS) 935 goto out; 936 937 if ((x->props.flags & XFRM_STATE_ESN)) 938 esp_input_restore_header(skb); 939 940 err = esp_input_done2(skb, err); 941 942 out: 943 return err; 944 } 945 946 static int esp4_err(struct sk_buff *skb, u32 info) 947 { 948 struct net *net = dev_net(skb->dev); 949 const struct iphdr *iph = (const struct iphdr *)skb->data; 950 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 951 struct xfrm_state *x; 952 953 switch (icmp_hdr(skb)->type) { 954 case ICMP_DEST_UNREACH: 955 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 956 return 0; 957 break; 958 case ICMP_REDIRECT: 959 break; 960 default: 961 return 0; 962 } 963 964 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr, 965 esph->spi, IPPROTO_ESP, AF_INET); 966 if (!x) 967 return 0; 968 969 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 970 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP); 971 else 972 ipv4_redirect(skb, net, 0, IPPROTO_ESP); 973 xfrm_state_put(x); 974 975 return 0; 976 } 977 978 static void esp_destroy(struct xfrm_state *x) 979 { 980 struct crypto_aead *aead = x->data; 981 982 if (!aead) 983 return; 984 985 crypto_free_aead(aead); 986 } 987 988 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack) 989 { 990 char aead_name[CRYPTO_MAX_ALG_NAME]; 991 struct crypto_aead *aead; 992 int err; 993 994 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)", 995 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) { 996 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 997 return -ENAMETOOLONG; 998 } 999 1000 aead = crypto_alloc_aead(aead_name, 0, 0); 1001 err = PTR_ERR(aead); 1002 if (IS_ERR(aead)) 1003 goto error; 1004 1005 x->data = aead; 1006 1007 err = crypto_aead_setkey(aead, x->aead->alg_key, 1008 (x->aead->alg_key_len + 7) / 8); 1009 if (err) 1010 goto error; 1011 1012 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 1013 if (err) 1014 goto error; 1015 1016 return 0; 1017 1018 error: 1019 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1020 return err; 1021 } 1022 1023 static int esp_init_authenc(struct xfrm_state *x, 1024 struct netlink_ext_ack *extack) 1025 { 1026 struct crypto_aead *aead; 1027 struct crypto_authenc_key_param *param; 1028 struct rtattr *rta; 1029 char *key; 1030 char *p; 1031 char authenc_name[CRYPTO_MAX_ALG_NAME]; 1032 unsigned int keylen; 1033 int err; 1034 1035 err = -ENAMETOOLONG; 1036 1037 if ((x->props.flags & XFRM_STATE_ESN)) { 1038 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1039 "%s%sauthencesn(%s,%s)%s", 1040 x->geniv ?: "", x->geniv ? "(" : "", 1041 x->aalg ? x->aalg->alg_name : "digest_null", 1042 x->ealg->alg_name, 1043 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1044 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1045 goto error; 1046 } 1047 } else { 1048 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 1049 "%s%sauthenc(%s,%s)%s", 1050 x->geniv ?: "", x->geniv ? "(" : "", 1051 x->aalg ? x->aalg->alg_name : "digest_null", 1052 x->ealg->alg_name, 1053 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) { 1054 NL_SET_ERR_MSG(extack, "Algorithm name is too long"); 1055 goto error; 1056 } 1057 } 1058 1059 aead = crypto_alloc_aead(authenc_name, 0, 0); 1060 err = PTR_ERR(aead); 1061 if (IS_ERR(aead)) { 1062 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1063 goto error; 1064 } 1065 1066 x->data = aead; 1067 1068 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 1069 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 1070 err = -ENOMEM; 1071 key = kmalloc(keylen, GFP_KERNEL); 1072 if (!key) 1073 goto error; 1074 1075 p = key; 1076 rta = (void *)p; 1077 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 1078 rta->rta_len = RTA_LENGTH(sizeof(*param)); 1079 param = RTA_DATA(rta); 1080 p += RTA_SPACE(sizeof(*param)); 1081 1082 if (x->aalg) { 1083 struct xfrm_algo_desc *aalg_desc; 1084 1085 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 1086 p += (x->aalg->alg_key_len + 7) / 8; 1087 1088 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 1089 BUG_ON(!aalg_desc); 1090 1091 err = -EINVAL; 1092 if (aalg_desc->uinfo.auth.icv_fullbits / 8 != 1093 crypto_aead_authsize(aead)) { 1094 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1095 goto free_key; 1096 } 1097 1098 err = crypto_aead_setauthsize( 1099 aead, x->aalg->alg_trunc_len / 8); 1100 if (err) { 1101 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations"); 1102 goto free_key; 1103 } 1104 } 1105 1106 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 1107 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 1108 1109 err = crypto_aead_setkey(aead, key, keylen); 1110 1111 free_key: 1112 kfree_sensitive(key); 1113 1114 error: 1115 return err; 1116 } 1117 1118 static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack) 1119 { 1120 struct crypto_aead *aead; 1121 u32 align; 1122 int err; 1123 1124 x->data = NULL; 1125 1126 if (x->aead) { 1127 err = esp_init_aead(x, extack); 1128 } else if (x->ealg) { 1129 err = esp_init_authenc(x, extack); 1130 } else { 1131 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided"); 1132 err = -EINVAL; 1133 } 1134 1135 if (err) 1136 goto error; 1137 1138 aead = x->data; 1139 1140 x->props.header_len = sizeof(struct ip_esp_hdr) + 1141 crypto_aead_ivsize(aead); 1142 if (x->props.mode == XFRM_MODE_TUNNEL) 1143 x->props.header_len += sizeof(struct iphdr); 1144 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6) 1145 x->props.header_len += IPV4_BEET_PHMAXLEN; 1146 if (x->encap) { 1147 struct xfrm_encap_tmpl *encap = x->encap; 1148 1149 switch (encap->encap_type) { 1150 default: 1151 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP"); 1152 err = -EINVAL; 1153 goto error; 1154 case UDP_ENCAP_ESPINUDP: 1155 x->props.header_len += sizeof(struct udphdr); 1156 break; 1157 #ifdef CONFIG_INET_ESPINTCP 1158 case TCP_ENCAP_ESPINTCP: 1159 /* only the length field, TCP encap is done by 1160 * the socket 1161 */ 1162 x->props.header_len += 2; 1163 break; 1164 #endif 1165 } 1166 } 1167 1168 align = ALIGN(crypto_aead_blocksize(aead), 4); 1169 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead); 1170 1171 error: 1172 return err; 1173 } 1174 1175 static int esp4_rcv_cb(struct sk_buff *skb, int err) 1176 { 1177 return 0; 1178 } 1179 1180 static const struct xfrm_type esp_type = 1181 { 1182 .owner = THIS_MODULE, 1183 .proto = IPPROTO_ESP, 1184 .flags = XFRM_TYPE_REPLAY_PROT, 1185 .init_state = esp_init_state, 1186 .destructor = esp_destroy, 1187 .input = esp_input, 1188 .output = esp_output, 1189 }; 1190 1191 static struct xfrm4_protocol esp4_protocol = { 1192 .handler = xfrm4_rcv, 1193 .input_handler = xfrm_input, 1194 .cb_handler = esp4_rcv_cb, 1195 .err_handler = esp4_err, 1196 .priority = 0, 1197 }; 1198 1199 static int __init esp4_init(void) 1200 { 1201 if (xfrm_register_type(&esp_type, AF_INET) < 0) { 1202 pr_info("%s: can't add xfrm type\n", __func__); 1203 return -EAGAIN; 1204 } 1205 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) { 1206 pr_info("%s: can't add protocol\n", __func__); 1207 xfrm_unregister_type(&esp_type, AF_INET); 1208 return -EAGAIN; 1209 } 1210 return 0; 1211 } 1212 1213 static void __exit esp4_fini(void) 1214 { 1215 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0) 1216 pr_info("%s: can't remove protocol\n", __func__); 1217 xfrm_unregister_type(&esp_type, AF_INET); 1218 } 1219 1220 module_init(esp4_init); 1221 module_exit(esp4_fini); 1222 MODULE_DESCRIPTION("IPv4 ESP transformation library"); 1223 MODULE_LICENSE("GPL"); 1224 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP); 1225