1 /* 2 * Copyright (C)2002 USAGI/WIDE Project 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License as published by 6 * the Free Software Foundation; either version 2 of the License, or 7 * (at your option) any later version. 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 17 * 18 * Authors 19 * 20 * Mitsuru KANDA @USAGI : IPv6 Support 21 * Kazunori MIYAZAWA @USAGI : 22 * Kunihiro Ishiguro <kunihiro@ipinfusion.com> 23 * 24 * This file is derived from net/ipv4/esp.c 25 */ 26 27 #include <crypto/aead.h> 28 #include <crypto/authenc.h> 29 #include <linux/err.h> 30 #include <linux/module.h> 31 #include <net/ip.h> 32 #include <net/xfrm.h> 33 #include <net/esp.h> 34 #include <linux/scatterlist.h> 35 #include <linux/kernel.h> 36 #include <linux/pfkeyv2.h> 37 #include <linux/random.h> 38 #include <linux/slab.h> 39 #include <linux/spinlock.h> 40 #include <net/icmp.h> 41 #include <net/ipv6.h> 42 #include <net/protocol.h> 43 #include <linux/icmpv6.h> 44 45 struct esp_skb_cb { 46 struct xfrm_skb_cb xfrm; 47 void *tmp; 48 }; 49 50 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0])) 51 52 static u32 esp6_get_mtu(struct xfrm_state *x, int mtu); 53 54 /* 55 * Allocate an AEAD request structure with extra space for SG and IV. 56 * 57 * For alignment considerations the upper 32 bits of the sequence number are 58 * placed at the front, if present. Followed by the IV, the request and finally 59 * the SG list. 60 * 61 * TODO: Use spare space in skb for this where possible. 62 */ 63 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen) 64 { 65 unsigned int len; 66 67 len = seqihlen; 68 69 len += crypto_aead_ivsize(aead); 70 71 if (len) { 72 len += crypto_aead_alignmask(aead) & 73 ~(crypto_tfm_ctx_alignment() - 1); 74 len = ALIGN(len, crypto_tfm_ctx_alignment()); 75 } 76 77 len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead); 78 len = ALIGN(len, __alignof__(struct scatterlist)); 79 80 len += sizeof(struct scatterlist) * nfrags; 81 82 return kmalloc(len, GFP_ATOMIC); 83 } 84 85 static inline __be32 *esp_tmp_seqhi(void *tmp) 86 { 87 return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32)); 88 } 89 90 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen) 91 { 92 return crypto_aead_ivsize(aead) ? 93 PTR_ALIGN((u8 *)tmp + seqhilen, 94 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen; 95 } 96 97 static inline struct aead_givcrypt_request *esp_tmp_givreq( 98 struct crypto_aead *aead, u8 *iv) 99 { 100 struct aead_givcrypt_request *req; 101 102 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead), 103 crypto_tfm_ctx_alignment()); 104 aead_givcrypt_set_tfm(req, aead); 105 return req; 106 } 107 108 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv) 109 { 110 struct aead_request *req; 111 112 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead), 113 crypto_tfm_ctx_alignment()); 114 aead_request_set_tfm(req, aead); 115 return req; 116 } 117 118 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead, 119 struct aead_request *req) 120 { 121 return (void *)ALIGN((unsigned long)(req + 1) + 122 crypto_aead_reqsize(aead), 123 __alignof__(struct scatterlist)); 124 } 125 126 static inline struct scatterlist *esp_givreq_sg( 127 struct crypto_aead *aead, struct aead_givcrypt_request *req) 128 { 129 return (void *)ALIGN((unsigned long)(req + 1) + 130 crypto_aead_reqsize(aead), 131 __alignof__(struct scatterlist)); 132 } 133 134 static void esp_output_done(struct crypto_async_request *base, int err) 135 { 136 struct sk_buff *skb = base->data; 137 138 kfree(ESP_SKB_CB(skb)->tmp); 139 xfrm_output_resume(skb, err); 140 } 141 142 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) 143 { 144 int err; 145 struct ip_esp_hdr *esph; 146 struct crypto_aead *aead; 147 struct aead_givcrypt_request *req; 148 struct scatterlist *sg; 149 struct scatterlist *asg; 150 struct sk_buff *trailer; 151 void *tmp; 152 int blksize; 153 int clen; 154 int alen; 155 int plen; 156 int tfclen; 157 int nfrags; 158 int assoclen; 159 int sglists; 160 int seqhilen; 161 u8 *iv; 162 u8 *tail; 163 __be32 *seqhi; 164 struct esp_data *esp = x->data; 165 166 /* skb is pure payload to encrypt */ 167 err = -ENOMEM; 168 169 aead = esp->aead; 170 alen = crypto_aead_authsize(aead); 171 172 tfclen = 0; 173 if (x->tfcpad) { 174 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb); 175 u32 padto; 176 177 padto = min(x->tfcpad, esp6_get_mtu(x, dst->child_mtu_cached)); 178 if (skb->len < padto) 179 tfclen = padto - skb->len; 180 } 181 blksize = ALIGN(crypto_aead_blocksize(aead), 4); 182 clen = ALIGN(skb->len + 2 + tfclen, blksize); 183 if (esp->padlen) 184 clen = ALIGN(clen, esp->padlen); 185 plen = clen - skb->len - tfclen; 186 187 err = skb_cow_data(skb, tfclen + plen + alen, &trailer); 188 if (err < 0) 189 goto error; 190 nfrags = err; 191 192 assoclen = sizeof(*esph); 193 sglists = 1; 194 seqhilen = 0; 195 196 if (x->props.flags & XFRM_STATE_ESN) { 197 sglists += 2; 198 seqhilen += sizeof(__be32); 199 assoclen += seqhilen; 200 } 201 202 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen); 203 if (!tmp) 204 goto error; 205 206 seqhi = esp_tmp_seqhi(tmp); 207 iv = esp_tmp_iv(aead, tmp, seqhilen); 208 req = esp_tmp_givreq(aead, iv); 209 asg = esp_givreq_sg(aead, req); 210 sg = asg + sglists; 211 212 /* Fill padding... */ 213 tail = skb_tail_pointer(trailer); 214 if (tfclen) { 215 memset(tail, 0, tfclen); 216 tail += tfclen; 217 } 218 do { 219 int i; 220 for (i = 0; i < plen - 2; i++) 221 tail[i] = i + 1; 222 } while (0); 223 tail[plen - 2] = plen - 2; 224 tail[plen - 1] = *skb_mac_header(skb); 225 pskb_put(skb, trailer, clen - skb->len + alen); 226 227 skb_push(skb, -skb_network_offset(skb)); 228 esph = ip_esp_hdr(skb); 229 *skb_mac_header(skb) = IPPROTO_ESP; 230 231 esph->spi = x->id.spi; 232 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 233 234 sg_init_table(sg, nfrags); 235 skb_to_sgvec(skb, sg, 236 esph->enc_data + crypto_aead_ivsize(aead) - skb->data, 237 clen + alen); 238 239 if ((x->props.flags & XFRM_STATE_ESN)) { 240 sg_init_table(asg, 3); 241 sg_set_buf(asg, &esph->spi, sizeof(__be32)); 242 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi); 243 sg_set_buf(asg + 1, seqhi, seqhilen); 244 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32)); 245 } else 246 sg_init_one(asg, esph, sizeof(*esph)); 247 248 aead_givcrypt_set_callback(req, 0, esp_output_done, skb); 249 aead_givcrypt_set_crypt(req, sg, sg, clen, iv); 250 aead_givcrypt_set_assoc(req, asg, assoclen); 251 aead_givcrypt_set_giv(req, esph->enc_data, 252 XFRM_SKB_CB(skb)->seq.output.low); 253 254 ESP_SKB_CB(skb)->tmp = tmp; 255 err = crypto_aead_givencrypt(req); 256 if (err == -EINPROGRESS) 257 goto error; 258 259 if (err == -EBUSY) 260 err = NET_XMIT_DROP; 261 262 kfree(tmp); 263 264 error: 265 return err; 266 } 267 268 static int esp_input_done2(struct sk_buff *skb, int err) 269 { 270 struct xfrm_state *x = xfrm_input_state(skb); 271 struct esp_data *esp = x->data; 272 struct crypto_aead *aead = esp->aead; 273 int alen = crypto_aead_authsize(aead); 274 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead); 275 int elen = skb->len - hlen; 276 int hdr_len = skb_network_header_len(skb); 277 int padlen; 278 u8 nexthdr[2]; 279 280 kfree(ESP_SKB_CB(skb)->tmp); 281 282 if (unlikely(err)) 283 goto out; 284 285 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2)) 286 BUG(); 287 288 err = -EINVAL; 289 padlen = nexthdr[0]; 290 if (padlen + 2 + alen >= elen) { 291 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage " 292 "padlen=%d, elen=%d\n", padlen + 2, elen - alen); 293 goto out; 294 } 295 296 /* ... check padding bits here. Silly. :-) */ 297 298 pskb_trim(skb, skb->len - alen - padlen - 2); 299 __skb_pull(skb, hlen); 300 skb_set_transport_header(skb, -hdr_len); 301 302 err = nexthdr[1]; 303 304 /* RFC4303: Drop dummy packets without any error */ 305 if (err == IPPROTO_NONE) 306 err = -EINVAL; 307 308 out: 309 return err; 310 } 311 312 static void esp_input_done(struct crypto_async_request *base, int err) 313 { 314 struct sk_buff *skb = base->data; 315 316 xfrm_input_resume(skb, esp_input_done2(skb, err)); 317 } 318 319 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) 320 { 321 struct ip_esp_hdr *esph; 322 struct esp_data *esp = x->data; 323 struct crypto_aead *aead = esp->aead; 324 struct aead_request *req; 325 struct sk_buff *trailer; 326 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead); 327 int nfrags; 328 int assoclen; 329 int sglists; 330 int seqhilen; 331 int ret = 0; 332 void *tmp; 333 __be32 *seqhi; 334 u8 *iv; 335 struct scatterlist *sg; 336 struct scatterlist *asg; 337 338 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) { 339 ret = -EINVAL; 340 goto out; 341 } 342 343 if (elen <= 0) { 344 ret = -EINVAL; 345 goto out; 346 } 347 348 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) { 349 ret = -EINVAL; 350 goto out; 351 } 352 353 ret = -ENOMEM; 354 355 assoclen = sizeof(*esph); 356 sglists = 1; 357 seqhilen = 0; 358 359 if (x->props.flags & XFRM_STATE_ESN) { 360 sglists += 2; 361 seqhilen += sizeof(__be32); 362 assoclen += seqhilen; 363 } 364 365 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen); 366 if (!tmp) 367 goto out; 368 369 ESP_SKB_CB(skb)->tmp = tmp; 370 seqhi = esp_tmp_seqhi(tmp); 371 iv = esp_tmp_iv(aead, tmp, seqhilen); 372 req = esp_tmp_req(aead, iv); 373 asg = esp_req_sg(aead, req); 374 sg = asg + 1; 375 376 skb->ip_summed = CHECKSUM_NONE; 377 378 esph = (struct ip_esp_hdr *)skb->data; 379 380 /* Get ivec. This can be wrong, check against another impls. */ 381 iv = esph->enc_data; 382 383 sg_init_table(sg, nfrags); 384 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen); 385 386 if ((x->props.flags & XFRM_STATE_ESN)) { 387 sg_init_table(asg, 3); 388 sg_set_buf(asg, &esph->spi, sizeof(__be32)); 389 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi; 390 sg_set_buf(asg + 1, seqhi, seqhilen); 391 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32)); 392 } else 393 sg_init_one(asg, esph, sizeof(*esph)); 394 395 aead_request_set_callback(req, 0, esp_input_done, skb); 396 aead_request_set_crypt(req, sg, sg, elen, iv); 397 aead_request_set_assoc(req, asg, assoclen); 398 399 ret = crypto_aead_decrypt(req); 400 if (ret == -EINPROGRESS) 401 goto out; 402 403 ret = esp_input_done2(skb, ret); 404 405 out: 406 return ret; 407 } 408 409 static u32 esp6_get_mtu(struct xfrm_state *x, int mtu) 410 { 411 struct esp_data *esp = x->data; 412 u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4); 413 u32 align = max_t(u32, blksize, esp->padlen); 414 u32 rem; 415 416 mtu -= x->props.header_len + crypto_aead_authsize(esp->aead); 417 rem = mtu & (align - 1); 418 mtu &= ~(align - 1); 419 420 if (x->props.mode != XFRM_MODE_TUNNEL) { 421 u32 padsize = ((blksize - 1) & 7) + 1; 422 mtu -= blksize - padsize; 423 mtu += min_t(u32, blksize - padsize, rem); 424 } 425 426 return mtu - 2; 427 } 428 429 static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 430 u8 type, u8 code, int offset, __be32 info) 431 { 432 struct net *net = dev_net(skb->dev); 433 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data; 434 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset); 435 struct xfrm_state *x; 436 437 if (type != ICMPV6_DEST_UNREACH && 438 type != ICMPV6_PKT_TOOBIG) 439 return; 440 441 x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6); 442 if (!x) 443 return; 444 printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%pI6\n", 445 ntohl(esph->spi), &iph->daddr); 446 xfrm_state_put(x); 447 } 448 449 static void esp6_destroy(struct xfrm_state *x) 450 { 451 struct esp_data *esp = x->data; 452 453 if (!esp) 454 return; 455 456 crypto_free_aead(esp->aead); 457 kfree(esp); 458 } 459 460 static int esp_init_aead(struct xfrm_state *x) 461 { 462 struct esp_data *esp = x->data; 463 struct crypto_aead *aead; 464 int err; 465 466 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0); 467 err = PTR_ERR(aead); 468 if (IS_ERR(aead)) 469 goto error; 470 471 esp->aead = aead; 472 473 err = crypto_aead_setkey(aead, x->aead->alg_key, 474 (x->aead->alg_key_len + 7) / 8); 475 if (err) 476 goto error; 477 478 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8); 479 if (err) 480 goto error; 481 482 error: 483 return err; 484 } 485 486 static int esp_init_authenc(struct xfrm_state *x) 487 { 488 struct esp_data *esp = x->data; 489 struct crypto_aead *aead; 490 struct crypto_authenc_key_param *param; 491 struct rtattr *rta; 492 char *key; 493 char *p; 494 char authenc_name[CRYPTO_MAX_ALG_NAME]; 495 unsigned int keylen; 496 int err; 497 498 err = -EINVAL; 499 if (x->ealg == NULL) 500 goto error; 501 502 err = -ENAMETOOLONG; 503 504 if ((x->props.flags & XFRM_STATE_ESN)) { 505 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 506 "authencesn(%s,%s)", 507 x->aalg ? x->aalg->alg_name : "digest_null", 508 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME) 509 goto error; 510 } else { 511 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, 512 "authenc(%s,%s)", 513 x->aalg ? x->aalg->alg_name : "digest_null", 514 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME) 515 goto error; 516 } 517 518 aead = crypto_alloc_aead(authenc_name, 0, 0); 519 err = PTR_ERR(aead); 520 if (IS_ERR(aead)) 521 goto error; 522 523 esp->aead = aead; 524 525 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) + 526 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param)); 527 err = -ENOMEM; 528 key = kmalloc(keylen, GFP_KERNEL); 529 if (!key) 530 goto error; 531 532 p = key; 533 rta = (void *)p; 534 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM; 535 rta->rta_len = RTA_LENGTH(sizeof(*param)); 536 param = RTA_DATA(rta); 537 p += RTA_SPACE(sizeof(*param)); 538 539 if (x->aalg) { 540 struct xfrm_algo_desc *aalg_desc; 541 542 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8); 543 p += (x->aalg->alg_key_len + 7) / 8; 544 545 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 546 BUG_ON(!aalg_desc); 547 548 err = -EINVAL; 549 if (aalg_desc->uinfo.auth.icv_fullbits/8 != 550 crypto_aead_authsize(aead)) { 551 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n", 552 x->aalg->alg_name, 553 crypto_aead_authsize(aead), 554 aalg_desc->uinfo.auth.icv_fullbits/8); 555 goto free_key; 556 } 557 558 err = crypto_aead_setauthsize( 559 aead, x->aalg->alg_trunc_len / 8); 560 if (err) 561 goto free_key; 562 } 563 564 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8); 565 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8); 566 567 err = crypto_aead_setkey(aead, key, keylen); 568 569 free_key: 570 kfree(key); 571 572 error: 573 return err; 574 } 575 576 static int esp6_init_state(struct xfrm_state *x) 577 { 578 struct esp_data *esp; 579 struct crypto_aead *aead; 580 u32 align; 581 int err; 582 583 if (x->encap) 584 return -EINVAL; 585 586 esp = kzalloc(sizeof(*esp), GFP_KERNEL); 587 if (esp == NULL) 588 return -ENOMEM; 589 590 x->data = esp; 591 592 if (x->aead) 593 err = esp_init_aead(x); 594 else 595 err = esp_init_authenc(x); 596 597 if (err) 598 goto error; 599 600 aead = esp->aead; 601 602 esp->padlen = 0; 603 604 x->props.header_len = sizeof(struct ip_esp_hdr) + 605 crypto_aead_ivsize(aead); 606 switch (x->props.mode) { 607 case XFRM_MODE_BEET: 608 if (x->sel.family != AF_INET6) 609 x->props.header_len += IPV4_BEET_PHMAXLEN + 610 (sizeof(struct ipv6hdr) - sizeof(struct iphdr)); 611 break; 612 case XFRM_MODE_TRANSPORT: 613 break; 614 case XFRM_MODE_TUNNEL: 615 x->props.header_len += sizeof(struct ipv6hdr); 616 break; 617 default: 618 goto error; 619 } 620 621 align = ALIGN(crypto_aead_blocksize(aead), 4); 622 if (esp->padlen) 623 align = max_t(u32, align, esp->padlen); 624 x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead); 625 626 error: 627 return err; 628 } 629 630 static const struct xfrm_type esp6_type = 631 { 632 .description = "ESP6", 633 .owner = THIS_MODULE, 634 .proto = IPPROTO_ESP, 635 .flags = XFRM_TYPE_REPLAY_PROT, 636 .init_state = esp6_init_state, 637 .destructor = esp6_destroy, 638 .get_mtu = esp6_get_mtu, 639 .input = esp6_input, 640 .output = esp6_output, 641 .hdr_offset = xfrm6_find_1stfragopt, 642 }; 643 644 static const struct inet6_protocol esp6_protocol = { 645 .handler = xfrm6_rcv, 646 .err_handler = esp6_err, 647 .flags = INET6_PROTO_NOPOLICY, 648 }; 649 650 static int __init esp6_init(void) 651 { 652 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { 653 printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n"); 654 return -EAGAIN; 655 } 656 if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) { 657 printk(KERN_INFO "ipv6 esp init: can't add protocol\n"); 658 xfrm_unregister_type(&esp6_type, AF_INET6); 659 return -EAGAIN; 660 } 661 662 return 0; 663 } 664 665 static void __exit esp6_fini(void) 666 { 667 if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0) 668 printk(KERN_INFO "ipv6 esp close: can't remove protocol\n"); 669 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0) 670 printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n"); 671 } 672 673 module_init(esp6_init); 674 module_exit(esp6_fini); 675 676 MODULE_LICENSE("GPL"); 677 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP); 678