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 case NEXTHDR_HOP: 275 if (!zero_out_mutable_opts(exthdr.opth)) { 276 net_dbg_ratelimited("overrun %sopts\n", 277 nexthdr == NEXTHDR_HOP ? 278 "hop" : "dest"); 279 return -EINVAL; 280 } 281 break; 282 283 case NEXTHDR_ROUTING: 284 ipv6_rearrange_rthdr(iph, exthdr.rth); 285 break; 286 287 default: 288 return 0; 289 } 290 291 nexthdr = exthdr.opth->nexthdr; 292 exthdr.raw += ipv6_optlen(exthdr.opth); 293 } 294 295 return 0; 296 } 297 298 static void ah6_output_done(struct crypto_async_request *base, int err) 299 { 300 int extlen; 301 u8 *iph_base; 302 u8 *icv; 303 struct sk_buff *skb = base->data; 304 struct xfrm_state *x = skb_dst(skb)->xfrm; 305 struct ah_data *ahp = x->data; 306 struct ipv6hdr *top_iph = ipv6_hdr(skb); 307 struct ip_auth_hdr *ah = ip_auth_hdr(skb); 308 struct tmp_ext *iph_ext; 309 310 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr); 311 if (extlen) 312 extlen += sizeof(*iph_ext); 313 314 iph_base = AH_SKB_CB(skb)->tmp; 315 iph_ext = ah_tmp_ext(iph_base); 316 icv = ah_tmp_icv(ahp->ahash, iph_ext, extlen); 317 318 memcpy(ah->auth_data, icv, ahp->icv_trunc_len); 319 memcpy(top_iph, iph_base, IPV6HDR_BASELEN); 320 321 if (extlen) { 322 #if IS_ENABLED(CONFIG_IPV6_MIP6) 323 memcpy(&top_iph->saddr, iph_ext, extlen); 324 #else 325 memcpy(&top_iph->daddr, iph_ext, extlen); 326 #endif 327 } 328 329 kfree(AH_SKB_CB(skb)->tmp); 330 xfrm_output_resume(skb, err); 331 } 332 333 static int ah6_output(struct xfrm_state *x, struct sk_buff *skb) 334 { 335 int err; 336 int nfrags; 337 int extlen; 338 u8 *iph_base; 339 u8 *icv; 340 u8 nexthdr; 341 struct sk_buff *trailer; 342 struct crypto_ahash *ahash; 343 struct ahash_request *req; 344 struct scatterlist *sg; 345 struct ipv6hdr *top_iph; 346 struct ip_auth_hdr *ah; 347 struct ah_data *ahp; 348 struct tmp_ext *iph_ext; 349 int seqhi_len = 0; 350 __be32 *seqhi; 351 int sglists = 0; 352 struct scatterlist *seqhisg; 353 354 ahp = x->data; 355 ahash = ahp->ahash; 356 357 err = skb_cow_data(skb, 0, &trailer); 358 if (err < 0) 359 goto out; 360 nfrags = err; 361 362 skb_push(skb, -skb_network_offset(skb)); 363 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr); 364 if (extlen) 365 extlen += sizeof(*iph_ext); 366 367 if (x->props.flags & XFRM_STATE_ESN) { 368 sglists = 1; 369 seqhi_len = sizeof(*seqhi); 370 } 371 err = -ENOMEM; 372 iph_base = ah_alloc_tmp(ahash, nfrags + sglists, IPV6HDR_BASELEN + 373 extlen + seqhi_len); 374 if (!iph_base) 375 goto out; 376 377 iph_ext = ah_tmp_ext(iph_base); 378 seqhi = (__be32 *)((char *)iph_ext + extlen); 379 icv = ah_tmp_icv(ahash, seqhi, seqhi_len); 380 req = ah_tmp_req(ahash, icv); 381 sg = ah_req_sg(ahash, req); 382 seqhisg = sg + nfrags; 383 384 ah = ip_auth_hdr(skb); 385 memset(ah->auth_data, 0, ahp->icv_trunc_len); 386 387 top_iph = ipv6_hdr(skb); 388 top_iph->payload_len = htons(skb->len - sizeof(*top_iph)); 389 390 nexthdr = *skb_mac_header(skb); 391 *skb_mac_header(skb) = IPPROTO_AH; 392 393 /* When there are no extension headers, we only need to save the first 394 * 8 bytes of the base IP header. 395 */ 396 memcpy(iph_base, top_iph, IPV6HDR_BASELEN); 397 398 if (extlen) { 399 #if IS_ENABLED(CONFIG_IPV6_MIP6) 400 memcpy(iph_ext, &top_iph->saddr, extlen); 401 #else 402 memcpy(iph_ext, &top_iph->daddr, extlen); 403 #endif 404 err = ipv6_clear_mutable_options(top_iph, 405 extlen - sizeof(*iph_ext) + 406 sizeof(*top_iph), 407 XFRM_POLICY_OUT); 408 if (err) 409 goto out_free; 410 } 411 412 ah->nexthdr = nexthdr; 413 414 top_iph->priority = 0; 415 top_iph->flow_lbl[0] = 0; 416 top_iph->flow_lbl[1] = 0; 417 top_iph->flow_lbl[2] = 0; 418 top_iph->hop_limit = 0; 419 420 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2; 421 422 ah->reserved = 0; 423 ah->spi = x->id.spi; 424 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low); 425 426 sg_init_table(sg, nfrags + sglists); 427 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len); 428 if (unlikely(err < 0)) 429 goto out_free; 430 431 if (x->props.flags & XFRM_STATE_ESN) { 432 /* Attach seqhi sg right after packet payload */ 433 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi); 434 sg_set_buf(seqhisg, seqhi, seqhi_len); 435 } 436 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len); 437 ahash_request_set_callback(req, 0, ah6_output_done, skb); 438 439 AH_SKB_CB(skb)->tmp = iph_base; 440 441 err = crypto_ahash_digest(req); 442 if (err) { 443 if (err == -EINPROGRESS) 444 goto out; 445 446 if (err == -EBUSY) 447 err = NET_XMIT_DROP; 448 goto out_free; 449 } 450 451 memcpy(ah->auth_data, icv, ahp->icv_trunc_len); 452 memcpy(top_iph, iph_base, IPV6HDR_BASELEN); 453 454 if (extlen) { 455 #if IS_ENABLED(CONFIG_IPV6_MIP6) 456 memcpy(&top_iph->saddr, iph_ext, extlen); 457 #else 458 memcpy(&top_iph->daddr, iph_ext, extlen); 459 #endif 460 } 461 462 out_free: 463 kfree(iph_base); 464 out: 465 return err; 466 } 467 468 static void ah6_input_done(struct crypto_async_request *base, int err) 469 { 470 u8 *auth_data; 471 u8 *icv; 472 u8 *work_iph; 473 struct sk_buff *skb = base->data; 474 struct xfrm_state *x = xfrm_input_state(skb); 475 struct ah_data *ahp = x->data; 476 struct ip_auth_hdr *ah = ip_auth_hdr(skb); 477 int hdr_len = skb_network_header_len(skb); 478 int ah_hlen = (ah->hdrlen + 2) << 2; 479 480 if (err) 481 goto out; 482 483 work_iph = AH_SKB_CB(skb)->tmp; 484 auth_data = ah_tmp_auth(work_iph, hdr_len); 485 icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len); 486 487 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0; 488 if (err) 489 goto out; 490 491 err = ah->nexthdr; 492 493 skb->network_header += ah_hlen; 494 memcpy(skb_network_header(skb), work_iph, hdr_len); 495 __skb_pull(skb, ah_hlen + hdr_len); 496 if (x->props.mode == XFRM_MODE_TUNNEL) 497 skb_reset_transport_header(skb); 498 else 499 skb_set_transport_header(skb, -hdr_len); 500 out: 501 kfree(AH_SKB_CB(skb)->tmp); 502 xfrm_input_resume(skb, err); 503 } 504 505 506 507 static int ah6_input(struct xfrm_state *x, struct sk_buff *skb) 508 { 509 /* 510 * Before process AH 511 * [IPv6][Ext1][Ext2][AH][Dest][Payload] 512 * |<-------------->| hdr_len 513 * 514 * To erase AH: 515 * Keeping copy of cleared headers. After AH processing, 516 * Moving the pointer of skb->network_header by using skb_pull as long 517 * as AH header length. Then copy back the copy as long as hdr_len 518 * If destination header following AH exists, copy it into after [Ext2]. 519 * 520 * |<>|[IPv6][Ext1][Ext2][Dest][Payload] 521 * There is offset of AH before IPv6 header after the process. 522 */ 523 524 u8 *auth_data; 525 u8 *icv; 526 u8 *work_iph; 527 struct sk_buff *trailer; 528 struct crypto_ahash *ahash; 529 struct ahash_request *req; 530 struct scatterlist *sg; 531 struct ip_auth_hdr *ah; 532 struct ipv6hdr *ip6h; 533 struct ah_data *ahp; 534 u16 hdr_len; 535 u16 ah_hlen; 536 int nexthdr; 537 int nfrags; 538 int err = -ENOMEM; 539 int seqhi_len = 0; 540 __be32 *seqhi; 541 int sglists = 0; 542 struct scatterlist *seqhisg; 543 544 if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr))) 545 goto out; 546 547 /* We are going to _remove_ AH header to keep sockets happy, 548 * so... Later this can change. */ 549 if (skb_unclone(skb, GFP_ATOMIC)) 550 goto out; 551 552 skb->ip_summed = CHECKSUM_NONE; 553 554 hdr_len = skb_network_header_len(skb); 555 ah = (struct ip_auth_hdr *)skb->data; 556 ahp = x->data; 557 ahash = ahp->ahash; 558 559 nexthdr = ah->nexthdr; 560 ah_hlen = (ah->hdrlen + 2) << 2; 561 562 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) && 563 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len)) 564 goto out; 565 566 if (!pskb_may_pull(skb, ah_hlen)) 567 goto out; 568 569 err = skb_cow_data(skb, 0, &trailer); 570 if (err < 0) 571 goto out; 572 nfrags = err; 573 574 ah = (struct ip_auth_hdr *)skb->data; 575 ip6h = ipv6_hdr(skb); 576 577 skb_push(skb, hdr_len); 578 579 if (x->props.flags & XFRM_STATE_ESN) { 580 sglists = 1; 581 seqhi_len = sizeof(*seqhi); 582 } 583 584 work_iph = ah_alloc_tmp(ahash, nfrags + sglists, hdr_len + 585 ahp->icv_trunc_len + seqhi_len); 586 if (!work_iph) { 587 err = -ENOMEM; 588 goto out; 589 } 590 591 auth_data = ah_tmp_auth((u8 *)work_iph, hdr_len); 592 seqhi = (__be32 *)(auth_data + ahp->icv_trunc_len); 593 icv = ah_tmp_icv(ahash, seqhi, seqhi_len); 594 req = ah_tmp_req(ahash, icv); 595 sg = ah_req_sg(ahash, req); 596 seqhisg = sg + nfrags; 597 598 memcpy(work_iph, ip6h, hdr_len); 599 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len); 600 memset(ah->auth_data, 0, ahp->icv_trunc_len); 601 602 if (ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN)) 603 goto out_free; 604 605 ip6h->priority = 0; 606 ip6h->flow_lbl[0] = 0; 607 ip6h->flow_lbl[1] = 0; 608 ip6h->flow_lbl[2] = 0; 609 ip6h->hop_limit = 0; 610 611 sg_init_table(sg, nfrags + sglists); 612 err = skb_to_sgvec_nomark(skb, sg, 0, skb->len); 613 if (unlikely(err < 0)) 614 goto out_free; 615 616 if (x->props.flags & XFRM_STATE_ESN) { 617 /* Attach seqhi sg right after packet payload */ 618 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi; 619 sg_set_buf(seqhisg, seqhi, seqhi_len); 620 } 621 622 ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len); 623 ahash_request_set_callback(req, 0, ah6_input_done, skb); 624 625 AH_SKB_CB(skb)->tmp = work_iph; 626 627 err = crypto_ahash_digest(req); 628 if (err) { 629 if (err == -EINPROGRESS) 630 goto out; 631 632 goto out_free; 633 } 634 635 err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0; 636 if (err) 637 goto out_free; 638 639 skb->network_header += ah_hlen; 640 memcpy(skb_network_header(skb), work_iph, hdr_len); 641 __skb_pull(skb, ah_hlen + hdr_len); 642 643 if (x->props.mode == XFRM_MODE_TUNNEL) 644 skb_reset_transport_header(skb); 645 else 646 skb_set_transport_header(skb, -hdr_len); 647 648 err = nexthdr; 649 650 out_free: 651 kfree(work_iph); 652 out: 653 return err; 654 } 655 656 static int ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, 657 u8 type, u8 code, int offset, __be32 info) 658 { 659 struct net *net = dev_net(skb->dev); 660 struct ipv6hdr *iph = (struct ipv6hdr *)skb->data; 661 struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+offset); 662 struct xfrm_state *x; 663 664 if (type != ICMPV6_PKT_TOOBIG && 665 type != NDISC_REDIRECT) 666 return 0; 667 668 x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6); 669 if (!x) 670 return 0; 671 672 if (type == NDISC_REDIRECT) 673 ip6_redirect(skb, net, skb->dev->ifindex, 0, 674 sock_net_uid(net, NULL)); 675 else 676 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL)); 677 xfrm_state_put(x); 678 679 return 0; 680 } 681 682 static int ah6_init_state(struct xfrm_state *x) 683 { 684 struct ah_data *ahp = NULL; 685 struct xfrm_algo_desc *aalg_desc; 686 struct crypto_ahash *ahash; 687 688 if (!x->aalg) 689 goto error; 690 691 if (x->encap) 692 goto error; 693 694 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL); 695 if (!ahp) 696 return -ENOMEM; 697 698 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0); 699 if (IS_ERR(ahash)) 700 goto error; 701 702 ahp->ahash = ahash; 703 if (crypto_ahash_setkey(ahash, x->aalg->alg_key, 704 (x->aalg->alg_key_len + 7) / 8)) 705 goto error; 706 707 /* 708 * Lookup the algorithm description maintained by xfrm_algo, 709 * verify crypto transform properties, and store information 710 * we need for AH processing. This lookup cannot fail here 711 * after a successful crypto_alloc_hash(). 712 */ 713 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); 714 BUG_ON(!aalg_desc); 715 716 if (aalg_desc->uinfo.auth.icv_fullbits/8 != 717 crypto_ahash_digestsize(ahash)) { 718 pr_info("AH: %s digestsize %u != %hu\n", 719 x->aalg->alg_name, crypto_ahash_digestsize(ahash), 720 aalg_desc->uinfo.auth.icv_fullbits/8); 721 goto error; 722 } 723 724 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8; 725 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8; 726 727 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) + 728 ahp->icv_trunc_len); 729 switch (x->props.mode) { 730 case XFRM_MODE_BEET: 731 case XFRM_MODE_TRANSPORT: 732 break; 733 case XFRM_MODE_TUNNEL: 734 x->props.header_len += sizeof(struct ipv6hdr); 735 break; 736 default: 737 goto error; 738 } 739 x->data = ahp; 740 741 return 0; 742 743 error: 744 if (ahp) { 745 crypto_free_ahash(ahp->ahash); 746 kfree(ahp); 747 } 748 return -EINVAL; 749 } 750 751 static void ah6_destroy(struct xfrm_state *x) 752 { 753 struct ah_data *ahp = x->data; 754 755 if (!ahp) 756 return; 757 758 crypto_free_ahash(ahp->ahash); 759 kfree(ahp); 760 } 761 762 static int ah6_rcv_cb(struct sk_buff *skb, int err) 763 { 764 return 0; 765 } 766 767 static const struct xfrm_type ah6_type = { 768 .description = "AH6", 769 .owner = THIS_MODULE, 770 .proto = IPPROTO_AH, 771 .flags = XFRM_TYPE_REPLAY_PROT, 772 .init_state = ah6_init_state, 773 .destructor = ah6_destroy, 774 .input = ah6_input, 775 .output = ah6_output, 776 .hdr_offset = xfrm6_find_1stfragopt, 777 }; 778 779 static struct xfrm6_protocol ah6_protocol = { 780 .handler = xfrm6_rcv, 781 .cb_handler = ah6_rcv_cb, 782 .err_handler = ah6_err, 783 .priority = 0, 784 }; 785 786 static int __init ah6_init(void) 787 { 788 if (xfrm_register_type(&ah6_type, AF_INET6) < 0) { 789 pr_info("%s: can't add xfrm type\n", __func__); 790 return -EAGAIN; 791 } 792 793 if (xfrm6_protocol_register(&ah6_protocol, IPPROTO_AH) < 0) { 794 pr_info("%s: can't add protocol\n", __func__); 795 xfrm_unregister_type(&ah6_type, AF_INET6); 796 return -EAGAIN; 797 } 798 799 return 0; 800 } 801 802 static void __exit ah6_fini(void) 803 { 804 if (xfrm6_protocol_deregister(&ah6_protocol, IPPROTO_AH) < 0) 805 pr_info("%s: can't remove protocol\n", __func__); 806 807 if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0) 808 pr_info("%s: can't remove xfrm type\n", __func__); 809 810 } 811 812 module_init(ah6_init); 813 module_exit(ah6_fini); 814 815 MODULE_LICENSE("GPL"); 816 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH); 817