~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

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

Version: ~ [ linux-5.6 ] ~ [ linux-5.5.13 ] ~ [ linux-5.4.28 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.113 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.174 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.217 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.217 ] ~ [ 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-3.16.82 ] ~ [ 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 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /*
  3  * Copyright (C)2002 USAGI/WIDE Project
  4  *
  5  * Authors
  6  *
  7  *      Mitsuru KANDA @USAGI       : IPv6 Support
  8  *      Kazunori MIYAZAWA @USAGI   :
  9  *      Kunihiro Ishiguro <kunihiro@ipinfusion.com>
 10  *
 11  *      This file is derived from net/ipv4/ah.c.
 12  */
 13 
 14 #define pr_fmt(fmt) "IPv6: " fmt
 15 
 16 #include <crypto/algapi.h>
 17 #include <crypto/hash.h>
 18 #include <linux/module.h>
 19 #include <linux/slab.h>
 20 #include <net/ip.h>
 21 #include <net/ah.h>
 22 #include <linux/crypto.h>
 23 #include <linux/pfkeyv2.h>
 24 #include <linux/string.h>
 25 #include <linux/scatterlist.h>
 26 #include <net/ip6_route.h>
 27 #include <net/icmp.h>
 28 #include <net/ipv6.h>
 29 #include <net/protocol.h>
 30 #include <net/xfrm.h>
 31 
 32 #define IPV6HDR_BASELEN 8
 33 
 34 struct tmp_ext {
 35 #if IS_ENABLED(CONFIG_IPV6_MIP6)
 36                 struct in6_addr saddr;
 37 #endif
 38                 struct in6_addr daddr;
 39                 char hdrs[0];
 40 };
 41 
 42 struct ah_skb_cb {
 43         struct xfrm_skb_cb xfrm;
 44         void *tmp;
 45 };
 46 
 47 #define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
 48 
 49 static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
 50                           unsigned int size)
 51 {
 52         unsigned int len;
 53 
 54         len = size + crypto_ahash_digestsize(ahash) +
 55               (crypto_ahash_alignmask(ahash) &
 56                ~(crypto_tfm_ctx_alignment() - 1));
 57 
 58         len = ALIGN(len, crypto_tfm_ctx_alignment());
 59 
 60         len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
 61         len = ALIGN(len, __alignof__(struct scatterlist));
 62 
 63         len += sizeof(struct scatterlist) * nfrags;
 64 
 65         return kmalloc(len, GFP_ATOMIC);
 66 }
 67 
 68 static inline struct tmp_ext *ah_tmp_ext(void *base)
 69 {
 70         return base + IPV6HDR_BASELEN;
 71 }
 72 
 73 static inline u8 *ah_tmp_auth(u8 *tmp, unsigned int offset)
 74 {
 75         return tmp + offset;
 76 }
 77 
 78 static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp,
 79                              unsigned int offset)
 80 {
 81         return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
 82 }
 83 
 84 static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
 85                                                u8 *icv)
 86 {
 87         struct ahash_request *req;
 88 
 89         req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
 90                                 crypto_tfm_ctx_alignment());
 91 
 92         ahash_request_set_tfm(req, ahash);
 93 
 94         return req;
 95 }
 96 
 97 static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
 98                                              struct ahash_request *req)
 99 {
100         return (void *)ALIGN((unsigned long)(req + 1) +
101                              crypto_ahash_reqsize(ahash),
102                              __alignof__(struct scatterlist));
103 }
104 
105 static bool zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr)
106 {
107         u8 *opt = (u8 *)opthdr;
108         int len = ipv6_optlen(opthdr);
109         int off = 0;
110         int optlen = 0;
111 
112         off += 2;
113         len -= 2;
114 
115         while (len > 0) {
116 
117                 switch (opt[off]) {
118 
119                 case IPV6_TLV_PAD1:
120                         optlen = 1;
121                         break;
122                 default:
123                         if (len < 2)
124                                 goto bad;
125                         optlen = opt[off+1]+2;
126                         if (len < optlen)
127                                 goto bad;
128                         if (opt[off] & 0x20)
129                                 memset(&opt[off+2], 0, opt[off+1]);
130                         break;
131                 }
132 
133                 off += optlen;
134                 len -= optlen;
135         }
136         if (len == 0)
137                 return true;
138 
139 bad:
140         return false;
141 }
142 
143 #if IS_ENABLED(CONFIG_IPV6_MIP6)
144 /**
145  *      ipv6_rearrange_destopt - rearrange IPv6 destination options header
146  *      @iph: IPv6 header
147  *      @destopt: destionation options header
148  */
149 static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt)
150 {
151         u8 *opt = (u8 *)destopt;
152         int len = ipv6_optlen(destopt);
153         int off = 0;
154         int optlen = 0;
155 
156         off += 2;
157         len -= 2;
158 
159         while (len > 0) {
160 
161                 switch (opt[off]) {
162 
163                 case IPV6_TLV_PAD1:
164                         optlen = 1;
165                         break;
166                 default:
167                         if (len < 2)
168                                 goto bad;
169                         optlen = opt[off+1]+2;
170                         if (len < optlen)
171                                 goto bad;
172 
173                         /* Rearrange the source address in @iph and the
174                          * addresses in home address option for final source.
175                          * See 11.3.2 of RFC 3775 for details.
176                          */
177                         if (opt[off] == IPV6_TLV_HAO) {
178                                 struct in6_addr final_addr;
179                                 struct ipv6_destopt_hao *hao;
180 
181                                 hao = (struct ipv6_destopt_hao *)&opt[off];
182                                 if (hao->length != sizeof(hao->addr)) {
183                                         net_warn_ratelimited("destopt hao: invalid header length: %u\n",
184                                                              hao->length);
185                                         goto bad;
186                                 }
187                                 final_addr = hao->addr;
188                                 hao->addr = iph->saddr;
189                                 iph->saddr = final_addr;
190                         }
191                         break;
192                 }
193 
194                 off += optlen;
195                 len -= optlen;
196         }
197         /* Note: ok if len == 0 */
198 bad:
199         return;
200 }
201 #else
202 static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt) {}
203 #endif
204 
205 /**
206  *      ipv6_rearrange_rthdr - rearrange IPv6 routing header
207  *      @iph: IPv6 header
208  *      @rthdr: routing header
209  *
210  *      Rearrange the destination address in @iph and the addresses in @rthdr
211  *      so that they appear in the order they will at the final destination.
212  *      See Appendix A2 of RFC 2402 for details.
213  */
214 static void ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr)
215 {
216         int segments, segments_left;
217         struct in6_addr *addrs;
218         struct in6_addr final_addr;
219 
220         segments_left = rthdr->segments_left;
221         if (segments_left == 0)
222                 return;
223         rthdr->segments_left = 0;
224 
225         /* The value of rthdr->hdrlen has been verified either by the system
226          * call if it is locally generated, or by ipv6_rthdr_rcv() for incoming
227          * packets.  So we can assume that it is even and that segments is
228          * greater than or equal to segments_left.
229          *
230          * For the same reason we can assume that this option is of type 0.
231          */
232         segments = rthdr->hdrlen >> 1;
233 
234         addrs = ((struct rt0_hdr *)rthdr)->addr;
235         final_addr = addrs[segments - 1];
236 
237         addrs += segments - segments_left;
238         memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
239 
240         addrs[0] = iph->daddr;
241         iph->daddr = final_addr;
242 }
243 
244 static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
245 {
246         union {
247                 struct ipv6hdr *iph;
248                 struct ipv6_opt_hdr *opth;
249                 struct ipv6_rt_hdr *rth;
250                 char *raw;
251         } exthdr = { .iph = iph };
252         char *end = exthdr.raw + len;
253         int nexthdr = iph->nexthdr;
254 
255         exthdr.iph++;
256 
257         while (exthdr.raw < end) {
258                 switch (nexthdr) {
259                 case NEXTHDR_DEST:
260                         if (dir == XFRM_POLICY_OUT)
261                                 ipv6_rearrange_destopt(iph, exthdr.opth);
262                         /* fall through */
263                 case NEXTHDR_HOP:
264                         if (!zero_out_mutable_opts(exthdr.opth)) {
265                                 net_dbg_ratelimited("overrun %sopts\n",
266                                                     nexthdr == NEXTHDR_HOP ?
267                                                     "hop" : "dest");
268                                 return -EINVAL;
269                         }
270                         break;
271 
272                 case NEXTHDR_ROUTING:
273                         ipv6_rearrange_rthdr(iph, exthdr.rth);
274                         break;
275 
276                 default:
277                         return 0;
278                 }
279 
280                 nexthdr = exthdr.opth->nexthdr;
281                 exthdr.raw += ipv6_optlen(exthdr.opth);
282         }
283 
284         return 0;
285 }
286 
287 static void ah6_output_done(struct crypto_async_request *base, int err)
288 {
289         int extlen;
290         u8 *iph_base;
291         u8 *icv;
292         struct sk_buff *skb = base->data;
293         struct xfrm_state *x = skb_dst(skb)->xfrm;
294         struct ah_data *ahp = x->data;
295         struct ipv6hdr *top_iph = ipv6_hdr(skb);
296         struct ip_auth_hdr *ah = ip_auth_hdr(skb);
297         struct tmp_ext *iph_ext;
298 
299         extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
300         if (extlen)
301                 extlen += sizeof(*iph_ext);
302 
303         iph_base = AH_SKB_CB(skb)->tmp;
304         iph_ext = ah_tmp_ext(iph_base);
305         icv = ah_tmp_icv(ahp->ahash, iph_ext, extlen);
306 
307         memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
308         memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
309 
310         if (extlen) {
311 #if IS_ENABLED(CONFIG_IPV6_MIP6)
312                 memcpy(&top_iph->saddr, iph_ext, extlen);
313 #else
314                 memcpy(&top_iph->daddr, iph_ext, extlen);
315 #endif
316         }
317 
318         kfree(AH_SKB_CB(skb)->tmp);
319         xfrm_output_resume(skb, err);
320 }
321 
322 static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
323 {
324         int err;
325         int nfrags;
326         int extlen;
327         u8 *iph_base;
328         u8 *icv;
329         u8 nexthdr;
330         struct sk_buff *trailer;
331         struct crypto_ahash *ahash;
332         struct ahash_request *req;
333         struct scatterlist *sg;
334         struct ipv6hdr *top_iph;
335         struct ip_auth_hdr *ah;
336         struct ah_data *ahp;
337         struct tmp_ext *iph_ext;
338         int seqhi_len = 0;
339         __be32 *seqhi;
340         int sglists = 0;
341         struct scatterlist *seqhisg;
342 
343         ahp = x->data;
344         ahash = ahp->ahash;
345 
346         err = skb_cow_data(skb, 0, &trailer);
347         if (err < 0)
348                 goto out;
349         nfrags = err;
350 
351         skb_push(skb, -skb_network_offset(skb));
352         extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
353         if (extlen)
354                 extlen += sizeof(*iph_ext);
355 
356         if (x->props.flags & XFRM_STATE_ESN) {
357                 sglists = 1;
358                 seqhi_len = sizeof(*seqhi);
359         }
360         err = -ENOMEM;
361         iph_base = ah_alloc_tmp(ahash, nfrags + sglists, IPV6HDR_BASELEN +
362                                 extlen + seqhi_len);
363         if (!iph_base)
364                 goto out;
365 
366         iph_ext = ah_tmp_ext(iph_base);
367         seqhi = (__be32 *)((char *)iph_ext + extlen);
368         icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
369         req = ah_tmp_req(ahash, icv);
370         sg = ah_req_sg(ahash, req);
371         seqhisg = sg + nfrags;
372 
373         ah = ip_auth_hdr(skb);
374         memset(ah->auth_data, 0, ahp->icv_trunc_len);
375 
376         top_iph = ipv6_hdr(skb);
377         top_iph->payload_len = htons(skb->len - sizeof(*top_iph));
378 
379         nexthdr = *skb_mac_header(skb);
380         *skb_mac_header(skb) = IPPROTO_AH;
381 
382         /* When there are no extension headers, we only need to save the first
383          * 8 bytes of the base IP header.
384          */
385         memcpy(iph_base, top_iph, IPV6HDR_BASELEN);
386 
387         if (extlen) {
388 #if IS_ENABLED(CONFIG_IPV6_MIP6)
389                 memcpy(iph_ext, &top_iph->saddr, extlen);
390 #else
391                 memcpy(iph_ext, &top_iph->daddr, extlen);
392 #endif
393                 err = ipv6_clear_mutable_options(top_iph,
394                                                  extlen - sizeof(*iph_ext) +
395                                                  sizeof(*top_iph),
396                                                  XFRM_POLICY_OUT);
397                 if (err)
398                         goto out_free;
399         }
400 
401         ah->nexthdr = nexthdr;
402 
403         top_iph->priority    = 0;
404         top_iph->flow_lbl[0] = 0;
405         top_iph->flow_lbl[1] = 0;
406         top_iph->flow_lbl[2] = 0;
407         top_iph->hop_limit   = 0;
408 
409         ah->hdrlen  = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
410 
411         ah->reserved = 0;
412         ah->spi = x->id.spi;
413         ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
414 
415         sg_init_table(sg, nfrags + sglists);
416         err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
417         if (unlikely(err < 0))
418                 goto out_free;
419 
420         if (x->props.flags & XFRM_STATE_ESN) {
421                 /* Attach seqhi sg right after packet payload */
422                 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
423                 sg_set_buf(seqhisg, seqhi, seqhi_len);
424         }
425         ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
426         ahash_request_set_callback(req, 0, ah6_output_done, skb);
427 
428         AH_SKB_CB(skb)->tmp = iph_base;
429 
430         err = crypto_ahash_digest(req);
431         if (err) {
432                 if (err == -EINPROGRESS)
433                         goto out;
434 
435                 if (err == -ENOSPC)
436                         err = NET_XMIT_DROP;
437                 goto out_free;
438         }
439 
440         memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
441         memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
442 
443         if (extlen) {
444 #if IS_ENABLED(CONFIG_IPV6_MIP6)
445                 memcpy(&top_iph->saddr, iph_ext, extlen);
446 #else
447                 memcpy(&top_iph->daddr, iph_ext, extlen);
448 #endif
449         }
450 
451 out_free:
452         kfree(iph_base);
453 out:
454         return err;
455 }
456 
457 static void ah6_input_done(struct crypto_async_request *base, int err)
458 {
459         u8 *auth_data;
460         u8 *icv;
461         u8 *work_iph;
462         struct sk_buff *skb = base->data;
463         struct xfrm_state *x = xfrm_input_state(skb);
464         struct ah_data *ahp = x->data;
465         struct ip_auth_hdr *ah = ip_auth_hdr(skb);
466         int hdr_len = skb_network_header_len(skb);
467         int ah_hlen = ipv6_authlen(ah);
468 
469         if (err)
470                 goto out;
471 
472         work_iph = AH_SKB_CB(skb)->tmp;
473         auth_data = ah_tmp_auth(work_iph, hdr_len);
474         icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
475 
476         err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
477         if (err)
478                 goto out;
479 
480         err = ah->nexthdr;
481 
482         skb->network_header += ah_hlen;
483         memcpy(skb_network_header(skb), work_iph, hdr_len);
484         __skb_pull(skb, ah_hlen + hdr_len);
485         if (x->props.mode == XFRM_MODE_TUNNEL)
486                 skb_reset_transport_header(skb);
487         else
488                 skb_set_transport_header(skb, -hdr_len);
489 out:
490         kfree(AH_SKB_CB(skb)->tmp);
491         xfrm_input_resume(skb, err);
492 }
493 
494 
495 
496 static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
497 {
498         /*
499          * Before process AH
500          * [IPv6][Ext1][Ext2][AH][Dest][Payload]
501          * |<-------------->| hdr_len
502          *
503          * To erase AH:
504          * Keeping copy of cleared headers. After AH processing,
505          * Moving the pointer of skb->network_header by using skb_pull as long
506          * as AH header length. Then copy back the copy as long as hdr_len
507          * If destination header following AH exists, copy it into after [Ext2].
508          *
509          * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
510          * There is offset of AH before IPv6 header after the process.
511          */
512 
513         u8 *auth_data;
514         u8 *icv;
515         u8 *work_iph;
516         struct sk_buff *trailer;
517         struct crypto_ahash *ahash;
518         struct ahash_request *req;
519         struct scatterlist *sg;
520         struct ip_auth_hdr *ah;
521         struct ipv6hdr *ip6h;
522         struct ah_data *ahp;
523         u16 hdr_len;
524         u16 ah_hlen;
525         int nexthdr;
526         int nfrags;
527         int err = -ENOMEM;
528         int seqhi_len = 0;
529         __be32 *seqhi;
530         int sglists = 0;
531         struct scatterlist *seqhisg;
532 
533         if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
534                 goto out;
535 
536         /* We are going to _remove_ AH header to keep sockets happy,
537          * so... Later this can change. */
538         if (skb_unclone(skb, GFP_ATOMIC))
539                 goto out;
540 
541         skb->ip_summed = CHECKSUM_NONE;
542 
543         hdr_len = skb_network_header_len(skb);
544         ah = (struct ip_auth_hdr *)skb->data;
545         ahp = x->data;
546         ahash = ahp->ahash;
547 
548         nexthdr = ah->nexthdr;
549         ah_hlen = ipv6_authlen(ah);
550 
551         if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
552             ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
553                 goto out;
554 
555         if (!pskb_may_pull(skb, ah_hlen))
556                 goto out;
557 
558         err = skb_cow_data(skb, 0, &trailer);
559         if (err < 0)
560                 goto out;
561         nfrags = err;
562 
563         ah = (struct ip_auth_hdr *)skb->data;
564         ip6h = ipv6_hdr(skb);
565 
566         skb_push(skb, hdr_len);
567 
568         if (x->props.flags & XFRM_STATE_ESN) {
569                 sglists = 1;
570                 seqhi_len = sizeof(*seqhi);
571         }
572 
573         work_iph = ah_alloc_tmp(ahash, nfrags + sglists, hdr_len +
574                                 ahp->icv_trunc_len + seqhi_len);
575         if (!work_iph) {
576                 err = -ENOMEM;
577                 goto out;
578         }
579 
580         auth_data = ah_tmp_auth((u8 *)work_iph, hdr_len);
581         seqhi = (__be32 *)(auth_data + ahp->icv_trunc_len);
582         icv = ah_tmp_icv(ahash, seqhi, seqhi_len);
583         req = ah_tmp_req(ahash, icv);
584         sg = ah_req_sg(ahash, req);
585         seqhisg = sg + nfrags;
586 
587         memcpy(work_iph, ip6h, hdr_len);
588         memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
589         memset(ah->auth_data, 0, ahp->icv_trunc_len);
590 
591         if (ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN))
592                 goto out_free;
593 
594         ip6h->priority    = 0;
595         ip6h->flow_lbl[0] = 0;
596         ip6h->flow_lbl[1] = 0;
597         ip6h->flow_lbl[2] = 0;
598         ip6h->hop_limit   = 0;
599 
600         sg_init_table(sg, nfrags + sglists);
601         err = skb_to_sgvec_nomark(skb, sg, 0, skb->len);
602         if (unlikely(err < 0))
603                 goto out_free;
604 
605         if (x->props.flags & XFRM_STATE_ESN) {
606                 /* Attach seqhi sg right after packet payload */
607                 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
608                 sg_set_buf(seqhisg, seqhi, seqhi_len);
609         }
610 
611         ahash_request_set_crypt(req, sg, icv, skb->len + seqhi_len);
612         ahash_request_set_callback(req, 0, ah6_input_done, skb);
613 
614         AH_SKB_CB(skb)->tmp = work_iph;
615 
616         err = crypto_ahash_digest(req);
617         if (err) {
618                 if (err == -EINPROGRESS)
619                         goto out;
620 
621                 goto out_free;
622         }
623 
624         err = crypto_memneq(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG : 0;
625         if (err)
626                 goto out_free;
627 
628         skb->network_header += ah_hlen;
629         memcpy(skb_network_header(skb), work_iph, hdr_len);
630         __skb_pull(skb, ah_hlen + hdr_len);
631 
632         if (x->props.mode == XFRM_MODE_TUNNEL)
633                 skb_reset_transport_header(skb);
634         else
635                 skb_set_transport_header(skb, -hdr_len);
636 
637         err = nexthdr;
638 
639 out_free:
640         kfree(work_iph);
641 out:
642         return err;
643 }
644 
645 static int ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
646                    u8 type, u8 code, int offset, __be32 info)
647 {
648         struct net *net = dev_net(skb->dev);
649         struct ipv6hdr *iph = (struct ipv6hdr *)skb->data;
650         struct ip_auth_hdr *ah = (struct ip_auth_hdr *)(skb->data+offset);
651         struct xfrm_state *x;
652 
653         if (type != ICMPV6_PKT_TOOBIG &&
654             type != NDISC_REDIRECT)
655                 return 0;
656 
657         x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
658         if (!x)
659                 return 0;
660 
661         if (type == NDISC_REDIRECT)
662                 ip6_redirect(skb, net, skb->dev->ifindex, 0,
663                              sock_net_uid(net, NULL));
664         else
665                 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
666         xfrm_state_put(x);
667 
668         return 0;
669 }
670 
671 static int ah6_init_state(struct xfrm_state *x)
672 {
673         struct ah_data *ahp = NULL;
674         struct xfrm_algo_desc *aalg_desc;
675         struct crypto_ahash *ahash;
676 
677         if (!x->aalg)
678                 goto error;
679 
680         if (x->encap)
681                 goto error;
682 
683         ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
684         if (!ahp)
685                 return -ENOMEM;
686 
687         ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
688         if (IS_ERR(ahash))
689                 goto error;
690 
691         ahp->ahash = ahash;
692         if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
693                                (x->aalg->alg_key_len + 7) / 8))
694                 goto error;
695 
696         /*
697          * Lookup the algorithm description maintained by xfrm_algo,
698          * verify crypto transform properties, and store information
699          * we need for AH processing.  This lookup cannot fail here
700          * after a successful crypto_alloc_hash().
701          */
702         aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
703         BUG_ON(!aalg_desc);
704 
705         if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
706             crypto_ahash_digestsize(ahash)) {
707                 pr_info("AH: %s digestsize %u != %hu\n",
708                         x->aalg->alg_name, crypto_ahash_digestsize(ahash),
709                         aalg_desc->uinfo.auth.icv_fullbits/8);
710                 goto error;
711         }
712 
713         ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
714         ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
715 
716         x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
717                                           ahp->icv_trunc_len);
718         switch (x->props.mode) {
719         case XFRM_MODE_BEET:
720         case XFRM_MODE_TRANSPORT:
721                 break;
722         case XFRM_MODE_TUNNEL:
723                 x->props.header_len += sizeof(struct ipv6hdr);
724                 break;
725         default:
726                 goto error;
727         }
728         x->data = ahp;
729 
730         return 0;
731 
732 error:
733         if (ahp) {
734                 crypto_free_ahash(ahp->ahash);
735                 kfree(ahp);
736         }
737         return -EINVAL;
738 }
739 
740 static void ah6_destroy(struct xfrm_state *x)
741 {
742         struct ah_data *ahp = x->data;
743 
744         if (!ahp)
745                 return;
746 
747         crypto_free_ahash(ahp->ahash);
748         kfree(ahp);
749 }
750 
751 static int ah6_rcv_cb(struct sk_buff *skb, int err)
752 {
753         return 0;
754 }
755 
756 static const struct xfrm_type ah6_type = {
757         .description    = "AH6",
758         .owner          = THIS_MODULE,
759         .proto          = IPPROTO_AH,
760         .flags          = XFRM_TYPE_REPLAY_PROT,
761         .init_state     = ah6_init_state,
762         .destructor     = ah6_destroy,
763         .input          = ah6_input,
764         .output         = ah6_output,
765         .hdr_offset     = xfrm6_find_1stfragopt,
766 };
767 
768 static struct xfrm6_protocol ah6_protocol = {
769         .handler        =       xfrm6_rcv,
770         .cb_handler     =       ah6_rcv_cb,
771         .err_handler    =       ah6_err,
772         .priority       =       0,
773 };
774 
775 static int __init ah6_init(void)
776 {
777         if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
778                 pr_info("%s: can't add xfrm type\n", __func__);
779                 return -EAGAIN;
780         }
781 
782         if (xfrm6_protocol_register(&ah6_protocol, IPPROTO_AH) < 0) {
783                 pr_info("%s: can't add protocol\n", __func__);
784                 xfrm_unregister_type(&ah6_type, AF_INET6);
785                 return -EAGAIN;
786         }
787 
788         return 0;
789 }
790 
791 static void __exit ah6_fini(void)
792 {
793         if (xfrm6_protocol_deregister(&ah6_protocol, IPPROTO_AH) < 0)
794                 pr_info("%s: can't remove protocol\n", __func__);
795 
796         xfrm_unregister_type(&ah6_type, AF_INET6);
797 }
798 
799 module_init(ah6_init);
800 module_exit(ah6_fini);
801 
802 MODULE_LICENSE("GPL");
803 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH);
804 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp