net: replace uses of NIP6_FMT with %p6
[linux-2.6.git] / net / ipv6 / ah6.c
1 /*
2  * Copyright (C)2002 USAGI/WIDE Project
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License as published by
6  * the Free Software Foundation; either version 2 of the License, or
7  * (at your option) any later version.
8  *
9  * This program is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
12  * GNU General Public License for more details.
13  *
14  * You should have received a copy of the GNU General Public License
15  * along with this program; if not, write to the Free Software
16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
17  *
18  * Authors
19  *
20  *      Mitsuru KANDA @USAGI       : IPv6 Support
21  *      Kazunori MIYAZAWA @USAGI   :
22  *      Kunihiro Ishiguro <kunihiro@ipinfusion.com>
23  *
24  *      This file is derived from net/ipv4/ah.c.
25  */
26
27 #include <linux/module.h>
28 #include <net/ip.h>
29 #include <net/ah.h>
30 #include <linux/crypto.h>
31 #include <linux/pfkeyv2.h>
32 #include <linux/spinlock.h>
33 #include <linux/string.h>
34 #include <net/icmp.h>
35 #include <net/ipv6.h>
36 #include <net/protocol.h>
37 #include <net/xfrm.h>
38
39 static int zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr)
40 {
41         u8 *opt = (u8 *)opthdr;
42         int len = ipv6_optlen(opthdr);
43         int off = 0;
44         int optlen = 0;
45
46         off += 2;
47         len -= 2;
48
49         while (len > 0) {
50
51                 switch (opt[off]) {
52
53                 case IPV6_TLV_PAD0:
54                         optlen = 1;
55                         break;
56                 default:
57                         if (len < 2)
58                                 goto bad;
59                         optlen = opt[off+1]+2;
60                         if (len < optlen)
61                                 goto bad;
62                         if (opt[off] & 0x20)
63                                 memset(&opt[off+2], 0, opt[off+1]);
64                         break;
65                 }
66
67                 off += optlen;
68                 len -= optlen;
69         }
70         if (len == 0)
71                 return 1;
72
73 bad:
74         return 0;
75 }
76
77 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
78 /**
79  *      ipv6_rearrange_destopt - rearrange IPv6 destination options header
80  *      @iph: IPv6 header
81  *      @destopt: destionation options header
82  */
83 static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt)
84 {
85         u8 *opt = (u8 *)destopt;
86         int len = ipv6_optlen(destopt);
87         int off = 0;
88         int optlen = 0;
89
90         off += 2;
91         len -= 2;
92
93         while (len > 0) {
94
95                 switch (opt[off]) {
96
97                 case IPV6_TLV_PAD0:
98                         optlen = 1;
99                         break;
100                 default:
101                         if (len < 2)
102                                 goto bad;
103                         optlen = opt[off+1]+2;
104                         if (len < optlen)
105                                 goto bad;
106
107                         /* Rearrange the source address in @iph and the
108                          * addresses in home address option for final source.
109                          * See 11.3.2 of RFC 3775 for details.
110                          */
111                         if (opt[off] == IPV6_TLV_HAO) {
112                                 struct in6_addr final_addr;
113                                 struct ipv6_destopt_hao *hao;
114
115                                 hao = (struct ipv6_destopt_hao *)&opt[off];
116                                 if (hao->length != sizeof(hao->addr)) {
117                                         if (net_ratelimit())
118                                                 printk(KERN_WARNING "destopt hao: invalid header length: %u\n", hao->length);
119                                         goto bad;
120                                 }
121                                 ipv6_addr_copy(&final_addr, &hao->addr);
122                                 ipv6_addr_copy(&hao->addr, &iph->saddr);
123                                 ipv6_addr_copy(&iph->saddr, &final_addr);
124                         }
125                         break;
126                 }
127
128                 off += optlen;
129                 len -= optlen;
130         }
131         /* Note: ok if len == 0 */
132 bad:
133         return;
134 }
135 #else
136 static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt) {}
137 #endif
138
139 /**
140  *      ipv6_rearrange_rthdr - rearrange IPv6 routing header
141  *      @iph: IPv6 header
142  *      @rthdr: routing header
143  *
144  *      Rearrange the destination address in @iph and the addresses in @rthdr
145  *      so that they appear in the order they will at the final destination.
146  *      See Appendix A2 of RFC 2402 for details.
147  */
148 static void ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr)
149 {
150         int segments, segments_left;
151         struct in6_addr *addrs;
152         struct in6_addr final_addr;
153
154         segments_left = rthdr->segments_left;
155         if (segments_left == 0)
156                 return;
157         rthdr->segments_left = 0;
158
159         /* The value of rthdr->hdrlen has been verified either by the system
160          * call if it is locally generated, or by ipv6_rthdr_rcv() for incoming
161          * packets.  So we can assume that it is even and that segments is
162          * greater than or equal to segments_left.
163          *
164          * For the same reason we can assume that this option is of type 0.
165          */
166         segments = rthdr->hdrlen >> 1;
167
168         addrs = ((struct rt0_hdr *)rthdr)->addr;
169         ipv6_addr_copy(&final_addr, addrs + segments - 1);
170
171         addrs += segments - segments_left;
172         memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
173
174         ipv6_addr_copy(addrs, &iph->daddr);
175         ipv6_addr_copy(&iph->daddr, &final_addr);
176 }
177
178 static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
179 {
180         union {
181                 struct ipv6hdr *iph;
182                 struct ipv6_opt_hdr *opth;
183                 struct ipv6_rt_hdr *rth;
184                 char *raw;
185         } exthdr = { .iph = iph };
186         char *end = exthdr.raw + len;
187         int nexthdr = iph->nexthdr;
188
189         exthdr.iph++;
190
191         while (exthdr.raw < end) {
192                 switch (nexthdr) {
193                 case NEXTHDR_DEST:
194                         if (dir == XFRM_POLICY_OUT)
195                                 ipv6_rearrange_destopt(iph, exthdr.opth);
196                 case NEXTHDR_HOP:
197                         if (!zero_out_mutable_opts(exthdr.opth)) {
198                                 LIMIT_NETDEBUG(
199                                         KERN_WARNING "overrun %sopts\n",
200                                         nexthdr == NEXTHDR_HOP ?
201                                                 "hop" : "dest");
202                                 return -EINVAL;
203                         }
204                         break;
205
206                 case NEXTHDR_ROUTING:
207                         ipv6_rearrange_rthdr(iph, exthdr.rth);
208                         break;
209
210                 default :
211                         return 0;
212                 }
213
214                 nexthdr = exthdr.opth->nexthdr;
215                 exthdr.raw += ipv6_optlen(exthdr.opth);
216         }
217
218         return 0;
219 }
220
221 static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
222 {
223         int err;
224         int extlen;
225         struct ipv6hdr *top_iph;
226         struct ip_auth_hdr *ah;
227         struct ah_data *ahp;
228         u8 nexthdr;
229         char tmp_base[8];
230         struct {
231 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
232                 struct in6_addr saddr;
233 #endif
234                 struct in6_addr daddr;
235                 char hdrs[0];
236         } *tmp_ext;
237
238         skb_push(skb, -skb_network_offset(skb));
239         top_iph = ipv6_hdr(skb);
240         top_iph->payload_len = htons(skb->len - sizeof(*top_iph));
241
242         nexthdr = *skb_mac_header(skb);
243         *skb_mac_header(skb) = IPPROTO_AH;
244
245         /* When there are no extension headers, we only need to save the first
246          * 8 bytes of the base IP header.
247          */
248         memcpy(tmp_base, top_iph, sizeof(tmp_base));
249
250         tmp_ext = NULL;
251         extlen = skb_transport_offset(skb) - sizeof(struct ipv6hdr);
252         if (extlen) {
253                 extlen += sizeof(*tmp_ext);
254                 tmp_ext = kmalloc(extlen, GFP_ATOMIC);
255                 if (!tmp_ext) {
256                         err = -ENOMEM;
257                         goto error;
258                 }
259 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
260                 memcpy(tmp_ext, &top_iph->saddr, extlen);
261 #else
262                 memcpy(tmp_ext, &top_iph->daddr, extlen);
263 #endif
264                 err = ipv6_clear_mutable_options(top_iph,
265                                                  extlen - sizeof(*tmp_ext) +
266                                                  sizeof(*top_iph),
267                                                  XFRM_POLICY_OUT);
268                 if (err)
269                         goto error_free_iph;
270         }
271
272         ah = ip_auth_hdr(skb);
273         ah->nexthdr = nexthdr;
274
275         top_iph->priority    = 0;
276         top_iph->flow_lbl[0] = 0;
277         top_iph->flow_lbl[1] = 0;
278         top_iph->flow_lbl[2] = 0;
279         top_iph->hop_limit   = 0;
280
281         ahp = x->data;
282         ah->hdrlen  = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
283
284         ah->reserved = 0;
285         ah->spi = x->id.spi;
286         ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output);
287
288         spin_lock_bh(&x->lock);
289         err = ah_mac_digest(ahp, skb, ah->auth_data);
290         memcpy(ah->auth_data, ahp->work_icv, ahp->icv_trunc_len);
291         spin_unlock_bh(&x->lock);
292
293         if (err)
294                 goto error_free_iph;
295
296         memcpy(top_iph, tmp_base, sizeof(tmp_base));
297         if (tmp_ext) {
298 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
299                 memcpy(&top_iph->saddr, tmp_ext, extlen);
300 #else
301                 memcpy(&top_iph->daddr, tmp_ext, extlen);
302 #endif
303 error_free_iph:
304                 kfree(tmp_ext);
305         }
306
307 error:
308         return err;
309 }
310
311 static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
312 {
313         /*
314          * Before process AH
315          * [IPv6][Ext1][Ext2][AH][Dest][Payload]
316          * |<-------------->| hdr_len
317          *
318          * To erase AH:
319          * Keeping copy of cleared headers. After AH processing,
320          * Moving the pointer of skb->network_header by using skb_pull as long
321          * as AH header length. Then copy back the copy as long as hdr_len
322          * If destination header following AH exists, copy it into after [Ext2].
323          *
324          * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
325          * There is offset of AH before IPv6 header after the process.
326          */
327
328         struct ip_auth_hdr *ah;
329         struct ipv6hdr *ip6h;
330         struct ah_data *ahp;
331         unsigned char *tmp_hdr = NULL;
332         u16 hdr_len;
333         u16 ah_hlen;
334         int nexthdr;
335         int err = -EINVAL;
336
337         if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
338                 goto out;
339
340         /* We are going to _remove_ AH header to keep sockets happy,
341          * so... Later this can change. */
342         if (skb_cloned(skb) &&
343             pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
344                 goto out;
345
346         skb->ip_summed = CHECKSUM_NONE;
347
348         hdr_len = skb->data - skb_network_header(skb);
349         ah = (struct ip_auth_hdr *)skb->data;
350         ahp = x->data;
351         nexthdr = ah->nexthdr;
352         ah_hlen = (ah->hdrlen + 2) << 2;
353
354         if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
355             ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
356                 goto out;
357
358         if (!pskb_may_pull(skb, ah_hlen))
359                 goto out;
360
361         tmp_hdr = kmemdup(skb_network_header(skb), hdr_len, GFP_ATOMIC);
362         if (!tmp_hdr)
363                 goto out;
364         ip6h = ipv6_hdr(skb);
365         if (ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN))
366                 goto free_out;
367         ip6h->priority    = 0;
368         ip6h->flow_lbl[0] = 0;
369         ip6h->flow_lbl[1] = 0;
370         ip6h->flow_lbl[2] = 0;
371         ip6h->hop_limit   = 0;
372
373         spin_lock(&x->lock);
374         {
375                 u8 auth_data[MAX_AH_AUTH_LEN];
376
377                 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
378                 memset(ah->auth_data, 0, ahp->icv_trunc_len);
379                 skb_push(skb, hdr_len);
380                 err = ah_mac_digest(ahp, skb, ah->auth_data);
381                 if (err)
382                         goto unlock;
383                 if (memcmp(ahp->work_icv, auth_data, ahp->icv_trunc_len))
384                         err = -EBADMSG;
385         }
386 unlock:
387         spin_unlock(&x->lock);
388
389         if (err)
390                 goto free_out;
391
392         skb->network_header += ah_hlen;
393         memcpy(skb_network_header(skb), tmp_hdr, hdr_len);
394         skb->transport_header = skb->network_header;
395         __skb_pull(skb, ah_hlen + hdr_len);
396
397         kfree(tmp_hdr);
398
399         return nexthdr;
400
401 free_out:
402         kfree(tmp_hdr);
403 out:
404         return err;
405 }
406
407 static void ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
408                     int type, int code, int offset, __be32 info)
409 {
410         struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
411         struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+offset);
412         struct xfrm_state *x;
413
414         if (type != ICMPV6_DEST_UNREACH &&
415             type != ICMPV6_PKT_TOOBIG)
416                 return;
417
418         x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
419         if (!x)
420                 return;
421
422         NETDEBUG(KERN_DEBUG "pmtu discovery on SA AH/%08x/%p6\n",
423                  ntohl(ah->spi), &iph->daddr);
424
425         xfrm_state_put(x);
426 }
427
428 static int ah6_init_state(struct xfrm_state *x)
429 {
430         struct ah_data *ahp = NULL;
431         struct xfrm_algo_desc *aalg_desc;
432         struct crypto_hash *tfm;
433
434         if (!x->aalg)
435                 goto error;
436
437         if (x->encap)
438                 goto error;
439
440         ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
441         if (ahp == NULL)
442                 return -ENOMEM;
443
444         tfm = crypto_alloc_hash(x->aalg->alg_name, 0, CRYPTO_ALG_ASYNC);
445         if (IS_ERR(tfm))
446                 goto error;
447
448         ahp->tfm = tfm;
449         if (crypto_hash_setkey(tfm, x->aalg->alg_key,
450                                (x->aalg->alg_key_len + 7) / 8))
451                 goto error;
452
453         /*
454          * Lookup the algorithm description maintained by xfrm_algo,
455          * verify crypto transform properties, and store information
456          * we need for AH processing.  This lookup cannot fail here
457          * after a successful crypto_alloc_hash().
458          */
459         aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
460         BUG_ON(!aalg_desc);
461
462         if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
463             crypto_hash_digestsize(tfm)) {
464                 printk(KERN_INFO "AH: %s digestsize %u != %hu\n",
465                        x->aalg->alg_name, crypto_hash_digestsize(tfm),
466                        aalg_desc->uinfo.auth.icv_fullbits/8);
467                 goto error;
468         }
469
470         ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
471         ahp->icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
472
473         BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
474
475         ahp->work_icv = kmalloc(ahp->icv_full_len, GFP_KERNEL);
476         if (!ahp->work_icv)
477                 goto error;
478
479         x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
480                                           ahp->icv_trunc_len);
481         switch (x->props.mode) {
482         case XFRM_MODE_BEET:
483         case XFRM_MODE_TRANSPORT:
484                 break;
485         case XFRM_MODE_TUNNEL:
486                 x->props.header_len += sizeof(struct ipv6hdr);
487                 break;
488         default:
489                 goto error;
490         }
491         x->data = ahp;
492
493         return 0;
494
495 error:
496         if (ahp) {
497                 kfree(ahp->work_icv);
498                 crypto_free_hash(ahp->tfm);
499                 kfree(ahp);
500         }
501         return -EINVAL;
502 }
503
504 static void ah6_destroy(struct xfrm_state *x)
505 {
506         struct ah_data *ahp = x->data;
507
508         if (!ahp)
509                 return;
510
511         kfree(ahp->work_icv);
512         ahp->work_icv = NULL;
513         crypto_free_hash(ahp->tfm);
514         ahp->tfm = NULL;
515         kfree(ahp);
516 }
517
518 static const struct xfrm_type ah6_type =
519 {
520         .description    = "AH6",
521         .owner          = THIS_MODULE,
522         .proto          = IPPROTO_AH,
523         .flags          = XFRM_TYPE_REPLAY_PROT,
524         .init_state     = ah6_init_state,
525         .destructor     = ah6_destroy,
526         .input          = ah6_input,
527         .output         = ah6_output,
528         .hdr_offset     = xfrm6_find_1stfragopt,
529 };
530
531 static struct inet6_protocol ah6_protocol = {
532         .handler        =       xfrm6_rcv,
533         .err_handler    =       ah6_err,
534         .flags          =       INET6_PROTO_NOPOLICY,
535 };
536
537 static int __init ah6_init(void)
538 {
539         if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
540                 printk(KERN_INFO "ipv6 ah init: can't add xfrm type\n");
541                 return -EAGAIN;
542         }
543
544         if (inet6_add_protocol(&ah6_protocol, IPPROTO_AH) < 0) {
545                 printk(KERN_INFO "ipv6 ah init: can't add protocol\n");
546                 xfrm_unregister_type(&ah6_type, AF_INET6);
547                 return -EAGAIN;
548         }
549
550         return 0;
551 }
552
553 static void __exit ah6_fini(void)
554 {
555         if (inet6_del_protocol(&ah6_protocol, IPPROTO_AH) < 0)
556                 printk(KERN_INFO "ipv6 ah close: can't remove protocol\n");
557
558         if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0)
559                 printk(KERN_INFO "ipv6 ah close: can't remove xfrm type\n");
560
561 }
562
563 module_init(ah6_init);
564 module_exit(ah6_fini);
565
566 MODULE_LICENSE("GPL");
567 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH);