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TOMOYO Linux Cross Reference
Linux/net/ipv6/ah6.c

Version: ~ [ linux-5.6-rc1 ] ~ [ linux-5.5.2 ] ~ [ linux-5.4.17 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.102 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.170 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.213 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.213 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.81 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

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

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