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, see <http://www.gnu.org/licenses/>. 16 * 17 * Authors 18 * 19 * Mitsuru KANDA @USAGI : IPv6 Support 20 * Kazunori MIYAZAWA @USAGI : 21 * Kunihiro Ishiguro <kunihiro@ipinfusion.com> 22 * 23 * This file is derived from net/ipv4/ah.c. 24 */ 25 26 #define pr_fmt(fmt) "IPv6: " fmt 27 28 #include <crypto/algapi.h> 29 #include <crypto/hash.h> 30 #include <linux/module.h> 31 #include <linux/slab.h> 32 #include <net/ip.h> 33 #include <net/ah.h> 34 #include <linux/crypto.h> 35 #include <linux/pfkeyv2.h> 36 #include <linux/string.h> 37 #include <linux/scatterlist.h> 38 #include <net/ip6_route.h> 39 #include <net/icmp.h> 40 #include <net/ipv6.h> 41 #include <net/protocol.h> 42 #include <net/xfrm.h> 43 44 #define IPV6HDR_BASELEN 8 45 46 struct tmp_ext { 47 #if IS_ENABLED(CONFIG_IPV6_MIP6) 48 struct in6_addr saddr; 49 #endif 50 struct in6_addr daddr; 51 char hdrs[0]; 52 }; 53 54 struct ah_skb_cb { 55 struct xfrm_skb_cb xfrm; 56 void *tmp; 57 }; 58 59 #define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0])) 60 61 static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags, 62 unsigned int size) 63 { 64 unsigned int len; 65 66 len = size + crypto_ahash_digestsize(ahash) + 67 (crypto_ahash_alignmask(ahash) & 68 ~(crypto_tfm_ctx_alignment() - 1)); 69 70 len = ALIGN(len, crypto_tfm_ctx_alignment()); 71 72 len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash); 73 len = ALIGN(len, __alignof__(struct scatterlist)); 74 75 len += sizeof(struct scatterlist) * nfrags; 76 77 return kmalloc(len, GFP_ATOMIC); 78 } 79 80 static inline struct tmp_ext *ah_tmp_ext(void *base) 81 { 82 return base + IPV6HDR_BASELEN; 83 } 84 85 static inline u8 *ah_tmp_auth(u8 *tmp, unsigned int offset) 86 { 87 return tmp + offset; 88 } 89 90 static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp, 91 unsigned int offset) 92 { 93 return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1); 94 } 95 96 static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash, 97 u8 *icv) 98 { 99 struct ahash_request *req; 100 101 req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash), 102 crypto_tfm_ctx_alignment()); 103 104 ahash_request_set_tfm(req, ahash); 105 106 return req; 107 } 108 109 static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash, 110 struct ahash_request *req) 111 { 112 return (void *)ALIGN((unsigned long)(req + 1) + 113 crypto_ahash_reqsize(ahash), 114 __alignof__(struct scatterlist)); 115 } 116 117 static bool zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr) 118 { 119 u8 *opt = (u8 *)opthdr; 120 int len = ipv6_optlen(opthdr); 121 int off = 0; 122 int optlen = 0; 123 124 off += 2; 125 len -= 2; 126 127 while (len > 0) { 128 129 switch (opt[off]) { 130 131 case IPV6_TLV_PAD1: 132 optlen = 1; 133 break; 134 default: 135 if (len < 2) 136 goto bad; 137 optlen = opt[off+1]+2; 138 if (len < optlen) 139 goto bad; 140 if (opt[off] & 0x20) 141 memset(&opt[off+2], 0, opt[off+1]); 142 break; 143 } 144 145 off += optlen; 146 len -= optlen; 147 } 148 if (len == 0) 149 return true; 150 151 bad: 152 return false; 153 } 154 155 #if IS_ENABLED(CONFIG_IPV6_MIP6) 156 /** 157 * ipv6_rearrange_destopt - rearrange IPv6 destination options header 158 * @iph: IPv6 header 159 * @destopt: destionation options header 160 */ 161 static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt) 162 { 163 u8 *opt = (u8 *)destopt; 164 int len = ipv6_optlen(destopt); 165 int off = 0; 166 int optlen = 0; 167 168 off += 2; 169 len -= 2; 170 171 while (len > 0) { 172 173 switch (opt[off]) { 174 175 case IPV6_TLV_PAD1: 176 optlen = 1; 177 break; 178 default: 179 if (len < 2) 180 goto bad; 181 optlen = opt[off+1]+2; 182 if (len < optlen) 183 goto bad; 184 185 /* Rearrange the source address in @iph and the 186 * addresses in home address option for final source. 187 * See 11.3.2 of RFC 3775 for details. 188 */ 189 if (opt[off] == IPV6_TLV_HAO) { 190 struct in6_addr final_addr; 191 struct ipv6_destopt_hao *hao; 192 193 hao = (struct ipv6_destopt_hao *)&opt[off]; 194 if (hao->length != sizeof(hao->addr)) { 195 net_warn_ratelimited("destopt hao: invalid header length: %u\n", 196 hao->length); 197 goto bad; 198 } 199 final_addr = hao->addr; 200 hao->addr = iph->saddr; 201 iph->saddr = final_addr; 202 } 203 break; 204 } 205 206 off += optlen; 207 len -= optlen; 208 } 209 /* Note: ok if len == 0 */ 210 bad: 211 return; 212 } 213 #else 214 static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt) {} 215 #endif 216 217 /** 218 * ipv6_rearrange_rthdr - rearrange IPv6 routing header 219 * @iph: IPv6 header 220 * @rthdr: routing header 221 * 222 * Rearrange the destination address in @iph and the addresses in @rthdr 223 * so that they appear in the order they will at the final destination. 224 * See Appendix A2 of RFC 2402 for details. 225 */ 226 static void ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr) 227 { 228 int segments, segments_left; 229 struct in6_addr *addrs; 230 struct in6_addr final_addr; 231 232 segments_left = rthdr->segments_left; 233 if (segments_left == 0) 234 return; 235 rthdr->segments_left = 0; 236 237 /* The value of rthdr->hdrlen has been verified either by the system 238 * call if it is locally generated, or by ipv6_rthdr_rcv() for incoming 239 * packets. So we can assume that it is even and that segments is 240 * greater than or equal to segments_left. 241 * 242 * For the same reason we can assume that this option is of type 0. 243 */ 244 segments = rthdr->hdrlen >> 1; 245 246 addrs = ((struct rt0_hdr *)rthdr)->addr; 247 final_addr = addrs[segments - 1]; 248 249 addrs += segments - segments_left; 250 memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs)); 251 252 addrs[0] = iph->daddr; 253 iph->daddr = final_addr; 254 } 255 256 static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir) 257 { 258 union { 259 struct ipv6hdr *iph; 260 struct ipv6_opt_hdr *opth; 261 struct ipv6_rt_hdr *rth; 262 char *raw; 263 } exthdr = { .iph = iph }; 264 char *end = exthdr.raw + len; 265 int nexthdr = iph->nexthdr; 266 267 exthdr.iph++; 268 269 while (exthdr.raw < end) { 270 switch (nexthdr) { 271 case NEXTHDR_DEST: 272 if (dir == XFRM_POLICY_OUT) 273 ipv6_rearrange_destopt(iph, exthdr.opth); 274 /* fall through */ 275 case NEXTHDR_HOP: 276 if (!zero_out_mutable_opts(exthdr.opth)) { 277 net_dbg_ratelimited("overrun %sopts\n", 278 nexthdr == NEXTHDR_HOP ? 279 "hop" : "dest"); 280 return -EINVAL; 281 } 282 break; 283 284 case NEXTHDR_ROUTING: 285 ipv6_rearrange_rthdr(iph, exthdr.rth); 286 break; 287 288 default: 289 return 0; 290 } 291 292 nexthdr = exthdr.opth->nexthdr; 293 exthdr.raw += ipv6_optlen(exthdr.opth); 294 } 295 296 return 0; 297 } 298 299 static void ah6_output_done(struct crypto_async_request *base, int err) 300 { 301 int extlen; 302 u8 *iph_base; 303 u8 *icv; 304 struct sk_buff *skb = base->data; 305 struct xfrm_state *x = skb_dst(skb)->xfrm; 306 struct ah_data *ahp = x->data; 307 struct ipv6hdr *top_iph = ipv6_hdr(skb); 308 struct ip_auth_hdr *ah = ip_auth_hdr(skb); 309 struct tmp_ext *iph_ext; 310 311 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr); 312 if (extlen) 313 extlen += sizeof(*iph_ext); 314 315 iph_base = AH_SKB_CB(skb)->tmp; 316 iph_ext = ah_tmp_ext(iph_base); 317 icv = ah_tmp_icv(ahp->ahash, iph_ext, extlen); 318 319 memcpy(ah->auth_data, icv, ahp->icv_trunc_len); 320 memcpy(top_iph, iph_base, IPV6HDR_BASELEN); 321 322 if (extlen) { 323 #if IS_ENABLED(CONFIG_IPV6_MIP6) 324 memcpy(&top_iph->saddr, iph_ext, extlen); 325 #else 326 memcpy(&top_iph->daddr, iph_ext, extlen); 327 #endif 328 } 329 330 kfree(AH_SKB_CB(skb)->tmp); 331 xfrm_output_resume(skb, err); 332 } 333 334 static int ah6_output(struct xfrm_state *x, struct sk_buff *skb) 335 { 336 int err; 337 int nfrags; 338 int extlen; 339 u8 *iph_base; 340 u8 *icv; 341 u8 nexthdr; 342 struct sk_buff *trailer; 343 struct crypto_ahash *ahash; 344 struct ahash_request *req; 345 struct scatterlist *sg; 346 struct ipv6hdr *top_iph; 347 struct ip_auth_hdr *ah; 348 struct ah_data *ahp; 349 struct tmp_ext *iph_ext; 350 int seqhi_len = 0; 351 __be32 *seqhi; 352 int sglists = 0; 353 struct scatterlist *seqhisg; 354 355 ahp = x->data; 356 ahash = ahp->ahash; 357 358 err = skb_cow_data(skb, 0, &trailer); 359 if (err < 0) 360 goto out; 361 nfrags = err; 362 363 skb_push(skb, -skb_network_offset(skb)); 364 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr); 365 if (extlen) 366 extlen += sizeof(*iph_ext); 367 368 if (x->props.flags & XFRM_STATE_ESN) { 369 sglists = 1; 370 seqhi_len = sizeof(*seqhi); 371 } 372 err = -ENOMEM; 373 iph_base = ah_alloc_tmp(ahash, nfrags + sglists, IPV6HDR_BASELEN + 374 extlen + seqhi_len); 375 if (!iph_base) 376 goto out; 377 378 iph_ext = ah_tmp_ext(iph_base); 379 seqhi = (__be32 *)((char *)iph_ext + extlen); 380 icv = ah_tmp_icv(ahash, seqhi, seqhi_len); 381 req = ah_tmp_req(ahash, icv); 382 sg = ah_req_sg(ahash, req); 383 seqhisg = sg + nfrags; 384 385 ah = ip_auth_hdr(skb); 386 memset(ah->auth_data, 0, ahp->icv_trunc_len); 387 388 top_iph = ipv6_hdr(skb); 389 top_iph->payload_len = htons(skb->len - sizeof(*top_iph)); 390 391 nexthdr = *skb_mac_header(skb); 392 *skb_mac_header(skb) = IPPROTO_AH; 393 394 /* When there are no extension headers, we only need to save the first 395 * 8 bytes of the base IP header. 396 */ 397 memcpy(iph_base, top_iph, IPV6HDR_BASELEN); 398 399 if (extlen) { 400 #if IS_ENABLED(CONFIG_IPV6_MIP6) 401 memcpy(iph_ext, &top_iph->saddr, extlen); 402 #else 403 memcpy(iph_ext, &top_iph->daddr, extlen); 404 #endif 405 err = ipv6_clear_mutable_options(top_iph, 406 extlen - sizeof(*iph_ext) + 407 sizeof(*top_iph), 408 XFRM_POLICY_OUT); 409 if (err) 410 goto out_free; 411 } 412 413 ah->nexthdr = nexthdr; 414 415 top_iph->priority = 0; 416 top_iph->flow_lbl[0] = 0; 417 top_iph->flow_lbl[1] = 0; 418 top_iph->flow_lbl[2] = 0; 419 top_iph->hop_limit = 0; 420 421 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2; 422 423 ah->reserved = 0; 424 ah->spi = x->id.spi; 425 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 426 427 sg_init_table(sg, nfrags + sglists); 428 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len); 429 if (unlikely(err < 0)) 430 goto out_free; 431 432 if (x->props.flags & XFRM_STATE_ESN) { 433 /* Attach seqhi sg right after packet payload */ 434 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi); 435 sg_set_buf(seqhisg, seqhi, seqhi_len); 436 } 437 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len); 438 ahash_request_set_callback(req, 0, ah6_output_done, skb); 439 440 AH_SKB_CB(skb)->tmp = iph_base; 441 442 err = crypto_ahash_digest(req); 443 if (err) { 444 if (err == -EINPROGRESS) 445 goto out; 446 447 if (err == -ENOSPC) 448 err = NET_XMIT_DROP; 449 goto out_free; 450 } 451 452 memcpy(ah->auth_data, icv, ahp->icv_trunc_len); 453 memcpy(top_iph, iph_base, IPV6HDR_BASELEN); 454 455 if (extlen) { 456 #if IS_ENABLED(CONFIG_IPV6_MIP6) 457 memcpy(&top_iph->saddr, iph_ext, extlen); 458 #else 459 memcpy(&top_iph->daddr, iph_ext, extlen); 460 #endif 461 } 462 463 out_free: 464 kfree(iph_base); 465 out: 466 return err; 467 } 468 469 static void ah6_input_done(struct crypto_async_request *base, int err) 470 { 471 u8 *auth_data; 472 u8 *icv; 473 u8 *work_iph; 474 struct sk_buff *skb = base->data; 475 struct xfrm_state *x = xfrm_input_state(skb); 476 struct ah_data *ahp = x->data; 477 struct ip_auth_hdr *ah = ip_auth_hdr(skb); 478 int hdr_len = skb_network_header_len(skb); 479 int ah_hlen = (ah->hdrlen + 2) << 2; 480 481 if (err) 482 goto out; 483 484 work_iph = AH_SKB_CB(skb)->tmp; 485 auth_data = ah_tmp_auth(work_iph, hdr_len); 486 icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len); 487 488 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0; 489 if (err) 490 goto out; 491 492 err = ah->nexthdr; 493 494 skb->network_header += ah_hlen; 495 memcpy(skb_network_header(skb), work_iph, hdr_len); 496 __skb_pull(skb, ah_hlen + hdr_len); 497 if (x->props.mode == XFRM_MODE_TUNNEL) 498 skb_reset_transport_header(skb); 499 else 500 skb_set_transport_header(skb, -hdr_len); 501 out: 502 kfree(AH_SKB_CB(skb)->tmp); 503 xfrm_input_resume(skb, err); 504 } 505 506 507 508 static int ah6_input(struct xfrm_state *x, struct sk_buff *skb) 509 { 510 /* 511 * Before process AH 512 * [IPv6][Ext1][Ext2][AH][Dest][Payload] 513 * |<-------------->| hdr_len 514 * 515 * To erase AH: 516 * Keeping copy of cleared headers. After AH processing, 517 * Moving the pointer of skb->network_header by using skb_pull as long 518 * as AH header length. Then copy back the copy as long as hdr_len 519 * If destination header following AH exists, copy it into after [Ext2]. 520 * 521 * |<>|[IPv6][Ext1][Ext2][Dest][Payload] 522 * There is offset of AH before IPv6 header after the process. 523 */ 524 525 u8 *auth_data; 526 u8 *icv; 527 u8 *work_iph; 528 struct sk_buff *trailer; 529 struct crypto_ahash *ahash; 530 struct ahash_request *req; 531 struct scatterlist *sg; 532 struct ip_auth_hdr *ah; 533 struct ipv6hdr *ip6h; 534 struct ah_data *ahp; 535 u16 hdr_len; 536 u16 ah_hlen; 537 int nexthdr; 538 int nfrags; 539 int err = -ENOMEM; 540 int seqhi_len = 0; 541 __be32 *seqhi; 542 int sglists = 0; 543 struct scatterlist *seqhisg; 544 545 if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr))) 546 goto out; 547 548 /* We are going to _remove_ AH header to keep sockets happy, 549 * so... Later this can change. */ 550 if (skb_unclone(skb, GFP_ATOMIC)) 551 goto out; 552 553 skb->ip_summed = CHECKSUM_NONE; 554 555 hdr_len = skb_network_header_len(skb); 556 ah = (struct ip_auth_hdr *)skb->data; 557 ahp = x->data; 558 ahash = ahp->ahash; 559 560 nexthdr = ah->nexthdr; 561 ah_hlen = (ah->hdrlen + 2) << 2; 562 563 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) && 564 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len)) 565 goto out; 566 567 if (!pskb_may_pull(skb, ah_hlen)) 568 goto out; 569 570 err = skb_cow_data(skb, 0, &trailer); 571 if (err < 0) 572 goto out; 573 nfrags = err; 574 575 ah = (struct ip_auth_hdr *)skb->data; 576 ip6h = ipv6_hdr(skb); 577 578 skb_push(skb, hdr_len); 579 580 if (x->props.flags & XFRM_STATE_ESN) { 581 sglists = 1; 582 seqhi_len = sizeof(*seqhi); 583 } 584 585 work_iph = ah_alloc_tmp(ahash, nfrags + sglists, hdr_len + 586 ahp->icv_trunc_len + seqhi_len); 587 if (!work_iph) { 588 err = -ENOMEM; 589 goto out; 590 } 591 592 auth_data = ah_tmp_auth((u8 *)work_iph, hdr_len); 593 seqhi = (__be32 *)(auth_data + ahp->icv_trunc_len); 594 icv = ah_tmp_icv(ahash, seqhi, seqhi_len); 595 req = ah_tmp_req(ahash, icv); 596 sg = ah_req_sg(ahash, req); 597 seqhisg = sg + nfrags; 598 599 memcpy(work_iph, ip6h, hdr_len); 600 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len); 601 memset(ah->auth_data, 0, ahp->icv_trunc_len); 602 603 if (ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN)) 604 goto out_free; 605 606 ip6h->priority = 0; 607 ip6h->flow_lbl[0] = 0; 608 ip6h->flow_lbl[1] = 0; 609 ip6h->flow_lbl[2] = 0; 610 ip6h->hop_limit = 0; 611 612 sg_init_table(sg, nfrags + sglists); 613 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len); 614 if (unlikely(err < 0)) 615 goto out_free; 616 617 if (x->props.flags & XFRM_STATE_ESN) { 618 /* Attach seqhi sg right after packet payload */ 619 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi; 620 sg_set_buf(seqhisg, seqhi, seqhi_len); 621 } 622 623 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len); 624 ahash_request_set_callback(req, 0, ah6_input_done, skb); 625 626 AH_SKB_CB(skb)->tmp = work_iph; 627 628 err = crypto_ahash_digest(req); 629 if (err) { 630 if (err == -EINPROGRESS) 631 goto out; 632 633 goto out_free; 634 } 635 636 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0; 637 if (err) 638 goto out_free; 639 640 skb->network_header += ah_hlen; 641 memcpy(skb_network_header(skb), work_iph, hdr_len); 642 __skb_pull(skb, ah_hlen + hdr_len); 643 644 if (x->props.mode == XFRM_MODE_TUNNEL) 645 skb_reset_transport_header(skb); 646 else 647 skb_set_transport_header(skb, -hdr_len); 648 649 err = nexthdr; 650 651 out_free: 652 kfree(work_iph); 653 out: 654 return err; 655 } 656 657 static int ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 658 u8 type, u8 code, int offset, __be32 info) 659 { 660 struct net *net = dev_net(skb->dev); 661 struct ipv6hdr *iph = (struct ipv6hdr *)skb->data; 662 struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+offset); 663 struct xfrm_state *x; 664 665 if (type != ICMPV6_PKT_TOOBIG && 666 type != NDISC_REDIRECT) 667 return 0; 668 669 x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6); 670 if (!x) 671 return 0; 672 673 if (type == NDISC_REDIRECT) 674 ip6_redirect(skb, net, skb->dev->ifindex, 0, 675 sock_net_uid(net, NULL)); 676 else 677 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 678 xfrm_state_put(x); 679 680 return 0; 681 } 682 683 static int ah6_init_state(struct xfrm_state *x) 684 { 685 struct ah_data *ahp = NULL; 686 struct xfrm_algo_desc *aalg_desc; 687 struct crypto_ahash *ahash; 688 689 if (!x->aalg) 690 goto error; 691 692 if (x->encap) 693 goto error; 694 695 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL); 696 if (!ahp) 697 return -ENOMEM; 698 699 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0); 700 if (IS_ERR(ahash)) 701 goto error; 702 703 ahp->ahash = ahash; 704 if (crypto_ahash_setkey(ahash, x->aalg->alg_key, 705 (x->aalg->alg_key_len + 7) / 8)) 706 goto error; 707 708 /* 709 * Lookup the algorithm description maintained by xfrm_algo, 710 * verify crypto transform properties, and store information 711 * we need for AH processing. This lookup cannot fail here 712 * after a successful crypto_alloc_hash(). 713 */ 714 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 715 BUG_ON(!aalg_desc); 716 717 if (aalg_desc->uinfo.auth.icv_fullbits/8 != 718 crypto_ahash_digestsize(ahash)) { 719 pr_info("AH: %s digestsize %u != %hu\n", 720 x->aalg->alg_name, crypto_ahash_digestsize(ahash), 721 aalg_desc->uinfo.auth.icv_fullbits/8); 722 goto error; 723 } 724 725 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8; 726 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8; 727 728 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + 729 ahp->icv_trunc_len); 730 switch (x->props.mode) { 731 case XFRM_MODE_BEET: 732 case XFRM_MODE_TRANSPORT: 733 break; 734 case XFRM_MODE_TUNNEL: 735 x->props.header_len += sizeof(struct ipv6hdr); 736 break; 737 default: 738 goto error; 739 } 740 x->data = ahp; 741 742 return 0; 743 744 error: 745 if (ahp) { 746 crypto_free_ahash(ahp->ahash); 747 kfree(ahp); 748 } 749 return -EINVAL; 750 } 751 752 static void ah6_destroy(struct xfrm_state *x) 753 { 754 struct ah_data *ahp = x->data; 755 756 if (!ahp) 757 return; 758 759 crypto_free_ahash(ahp->ahash); 760 kfree(ahp); 761 } 762 763 static int ah6_rcv_cb(struct sk_buff *skb, int err) 764 { 765 return 0; 766 } 767 768 static const struct xfrm_type ah6_type = { 769 .description = "AH6", 770 .owner = THIS_MODULE, 771 .proto = IPPROTO_AH, 772 .flags = XFRM_TYPE_REPLAY_PROT, 773 .init_state = ah6_init_state, 774 .destructor = ah6_destroy, 775 .input = ah6_input, 776 .output = ah6_output, 777 .hdr_offset = xfrm6_find_1stfragopt, 778 }; 779 780 static struct xfrm6_protocol ah6_protocol = { 781 .handler = xfrm6_rcv, 782 .cb_handler = ah6_rcv_cb, 783 .err_handler = ah6_err, 784 .priority = 0, 785 }; 786 787 static int __init ah6_init(void) 788 { 789 if (xfrm_register_type(&ah6_type, AF_INET6) < 0) { 790 pr_info("%s: can't add xfrm type\n", __func__); 791 return -EAGAIN; 792 } 793 794 if (xfrm6_protocol_register(&ah6_protocol, IPPROTO_AH) < 0) { 795 pr_info("%s: can't add protocol\n", __func__); 796 xfrm_unregister_type(&ah6_type, AF_INET6); 797 return -EAGAIN; 798 } 799 800 return 0; 801 } 802 803 static void __exit ah6_fini(void) 804 { 805 if (xfrm6_protocol_deregister(&ah6_protocol, IPPROTO_AH) < 0) 806 pr_info("%s: can't remove protocol\n", __func__); 807 808 if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0) 809 pr_info("%s: can't remove xfrm type\n", __func__); 810 811 } 812 813 module_init(ah6_init); 814 module_exit(ah6_fini); 815 816 MODULE_LICENSE("GPL"); 817 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH); 818