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[IPV4]: route: fix crash ip_route_input
[linux-2.6/sactl.git] / net / ipv4 / esp4.c
blob258d17631b4bb9b1767b8a8afa8582250f046a3a
1 #include <crypto/aead.h>
2 #include <crypto/authenc.h>
3 #include <linux/err.h>
4 #include <linux/module.h>
5 #include <net/ip.h>
6 #include <net/xfrm.h>
7 #include <net/esp.h>
8 #include <linux/scatterlist.h>
9 #include <linux/kernel.h>
10 #include <linux/pfkeyv2.h>
11 #include <linux/rtnetlink.h>
12 #include <linux/slab.h>
13 #include <linux/spinlock.h>
14 #include <linux/in6.h>
15 #include <net/icmp.h>
16 #include <net/protocol.h>
17 #include <net/udp.h>
18
19 struct esp_skb_cb {
20 struct xfrm_skb_cb xfrm;
21 void *tmp;
22 };
23
24 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
25
26 /*
27 * Allocate an AEAD request structure with extra space for SG and IV.
28 *
29 * For alignment considerations the IV is placed at the front, followed
30 * by the request and finally the SG list.
31 *
32 * TODO: Use spare space in skb for this where possible.
33 */
34 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags)
35 {
36 unsigned int len;
37
38 len = crypto_aead_ivsize(aead);
39 if (len) {
40 len += crypto_aead_alignmask(aead) &
41 ~(crypto_tfm_ctx_alignment() - 1);
42 len = ALIGN(len, crypto_tfm_ctx_alignment());
43 }
44
45 len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
46 len = ALIGN(len, __alignof__(struct scatterlist));
47
48 len += sizeof(struct scatterlist) * nfrags;
49
50 return kmalloc(len, GFP_ATOMIC);
51 }
52
53 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp)
54 {
55 return crypto_aead_ivsize(aead) ?
56 PTR_ALIGN((u8 *)tmp, crypto_aead_alignmask(aead) + 1) : tmp;
57 }
58
59 static inline struct aead_givcrypt_request *esp_tmp_givreq(
60 struct crypto_aead *aead, u8 *iv)
61 {
62 struct aead_givcrypt_request *req;
63
64 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
65 crypto_tfm_ctx_alignment());
66 aead_givcrypt_set_tfm(req, aead);
67 return req;
68 }
69
70 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
71 {
72 struct aead_request *req;
73
74 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
75 crypto_tfm_ctx_alignment());
76 aead_request_set_tfm(req, aead);
77 return req;
78 }
79
80 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
81 struct aead_request *req)
82 {
83 return (void *)ALIGN((unsigned long)(req + 1) +
84 crypto_aead_reqsize(aead),
85 __alignof__(struct scatterlist));
86 }
87
88 static inline struct scatterlist *esp_givreq_sg(
89 struct crypto_aead *aead, struct aead_givcrypt_request *req)
90 {
91 return (void *)ALIGN((unsigned long)(req + 1) +
92 crypto_aead_reqsize(aead),
93 __alignof__(struct scatterlist));
94 }
95
96 static void esp_output_done(struct crypto_async_request *base, int err)
97 {
98 struct sk_buff *skb = base->data;
99
100 kfree(ESP_SKB_CB(skb)->tmp);
101 xfrm_output_resume(skb, err);
102 }
103
104 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
105 {
106 int err;
107 struct ip_esp_hdr *esph;
108 struct crypto_aead *aead;
109 struct aead_givcrypt_request *req;
110 struct scatterlist *sg;
111 struct scatterlist *asg;
112 struct esp_data *esp;
113 struct sk_buff *trailer;
114 void *tmp;
115 u8 *iv;
116 u8 *tail;
117 int blksize;
118 int clen;
119 int alen;
120 int nfrags;
121
122 /* skb is pure payload to encrypt */
123
124 err = -ENOMEM;
125
126 /* Round to block size */
127 clen = skb->len;
128
129 esp = x->data;
130 aead = esp->aead;
131 alen = crypto_aead_authsize(aead);
132
133 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
134 clen = ALIGN(clen + 2, blksize);
135 if (esp->padlen)
136 clen = ALIGN(clen, esp->padlen);
137
138 if ((err = skb_cow_data(skb, clen - skb->len + alen, &trailer)) < 0)
139 goto error;
140 nfrags = err;
141
142 tmp = esp_alloc_tmp(aead, nfrags + 1);
143 if (!tmp)
144 goto error;
145
146 iv = esp_tmp_iv(aead, tmp);
147 req = esp_tmp_givreq(aead, iv);
148 asg = esp_givreq_sg(aead, req);
149 sg = asg + 1;
150
151 /* Fill padding... */
152 tail = skb_tail_pointer(trailer);
153 do {
154 int i;
155 for (i=0; i<clen-skb->len - 2; i++)
156 tail[i] = i + 1;
157 } while (0);
158 tail[clen - skb->len - 2] = (clen - skb->len) - 2;
159 tail[clen - skb->len - 1] = *skb_mac_header(skb);
160 pskb_put(skb, trailer, clen - skb->len + alen);
161
162 skb_push(skb, -skb_network_offset(skb));
163 esph = ip_esp_hdr(skb);
164 *skb_mac_header(skb) = IPPROTO_ESP;
165
166 /* this is non-NULL only with UDP Encapsulation */
167 if (x->encap) {
168 struct xfrm_encap_tmpl *encap = x->encap;
169 struct udphdr *uh;
170 __be32 *udpdata32;
171 unsigned int sport, dport;
172 int encap_type;
173
174 spin_lock_bh(&x->lock);
175 sport = encap->encap_sport;
176 dport = encap->encap_dport;
177 encap_type = encap->encap_type;
178 spin_unlock_bh(&x->lock);
179
180 uh = (struct udphdr *)esph;
181 uh->source = sport;
182 uh->dest = dport;
183 uh->len = htons(skb->len - skb_transport_offset(skb));
184 uh->check = 0;
185
186 switch (encap_type) {
187 default:
188 case UDP_ENCAP_ESPINUDP:
189 esph = (struct ip_esp_hdr *)(uh + 1);
190 break;
191 case UDP_ENCAP_ESPINUDP_NON_IKE:
192 udpdata32 = (__be32 *)(uh + 1);
193 udpdata32[0] = udpdata32[1] = 0;
194 esph = (struct ip_esp_hdr *)(udpdata32 + 2);
195 break;
196 }
197
198 *skb_mac_header(skb) = IPPROTO_UDP;
199 }
200
201 esph->spi = x->id.spi;
202 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
203
204 sg_init_table(sg, nfrags);
205 skb_to_sgvec(skb, sg,
206 esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
207 clen + alen);
208 sg_init_one(asg, esph, sizeof(*esph));
209
210 aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
211 aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
212 aead_givcrypt_set_assoc(req, asg, sizeof(*esph));
213 aead_givcrypt_set_giv(req, esph->enc_data, XFRM_SKB_CB(skb)->seq);
214
215 ESP_SKB_CB(skb)->tmp = tmp;
216 err = crypto_aead_givencrypt(req);
217 if (err == -EINPROGRESS)
218 goto error;
219
220 if (err == -EBUSY)
221 err = NET_XMIT_DROP;
222
223 kfree(tmp);
224
225 error:
226 return err;
227 }
228
229 static int esp_input_done2(struct sk_buff *skb, int err)
230 {
231 struct iphdr *iph;
232 struct xfrm_state *x = xfrm_input_state(skb);
233 struct esp_data *esp = x->data;
234 struct crypto_aead *aead = esp->aead;
235 int alen = crypto_aead_authsize(aead);
236 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
237 int elen = skb->len - hlen;
238 int ihl;
239 u8 nexthdr[2];
240 int padlen;
241
242 kfree(ESP_SKB_CB(skb)->tmp);
243
244 if (unlikely(err))
245 goto out;
246
247 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
248 BUG();
249
250 err = -EINVAL;
251 padlen = nexthdr[0];
252 if (padlen + 2 + alen >= elen)
253 goto out;
254
255 /* ... check padding bits here. Silly. :-) */
256
257 iph = ip_hdr(skb);
258 ihl = iph->ihl * 4;
259
260 if (x->encap) {
261 struct xfrm_encap_tmpl *encap = x->encap;
262 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
263
264 /*
265 * 1) if the NAT-T peer's IP or port changed then
266 * advertize the change to the keying daemon.
267 * This is an inbound SA, so just compare
268 * SRC ports.
269 */
270 if (iph->saddr != x->props.saddr.a4 ||
271 uh->source != encap->encap_sport) {
272 xfrm_address_t ipaddr;
273
274 ipaddr.a4 = iph->saddr;
275 km_new_mapping(x, &ipaddr, uh->source);
276
277 /* XXX: perhaps add an extra
278 * policy check here, to see
279 * if we should allow or
280 * reject a packet from a
281 * different source
282 * address/port.
283 */
284 }
285
286 /*
287 * 2) ignore UDP/TCP checksums in case
288 * of NAT-T in Transport Mode, or
289 * perform other post-processing fixes
290 * as per draft-ietf-ipsec-udp-encaps-06,
291 * section 3.1.2
292 */
293 if (x->props.mode == XFRM_MODE_TRANSPORT)
294 skb->ip_summed = CHECKSUM_UNNECESSARY;
295 }
296
297 pskb_trim(skb, skb->len - alen - padlen - 2);
298 __skb_pull(skb, hlen);
299 skb_set_transport_header(skb, -ihl);
300
301 err = nexthdr[1];
302
303 /* RFC4303: Drop dummy packets without any error */
304 if (err == IPPROTO_NONE)
305 err = -EINVAL;
306
307 out:
308 return err;
309 }
310
311 static void esp_input_done(struct crypto_async_request *base, int err)
312 {
313 struct sk_buff *skb = base->data;
314
315 xfrm_input_resume(skb, esp_input_done2(skb, err));
316 }
317
318 /*
319 * Note: detecting truncated vs. non-truncated authentication data is very
320 * expensive, so we only support truncated data, which is the recommended
321 * and common case.
322 */
323 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
324 {
325 struct ip_esp_hdr *esph;
326 struct esp_data *esp = x->data;
327 struct crypto_aead *aead = esp->aead;
328 struct aead_request *req;
329 struct sk_buff *trailer;
330 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
331 int nfrags;
332 void *tmp;
333 u8 *iv;
334 struct scatterlist *sg;
335 struct scatterlist *asg;
336 int err = -EINVAL;
337
338 if (!pskb_may_pull(skb, sizeof(*esph)))
339 goto out;
340
341 if (elen <= 0)
342 goto out;
343
344 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
345 goto out;
346 nfrags = err;
347
348 err = -ENOMEM;
349 tmp = esp_alloc_tmp(aead, nfrags + 1);
350 if (!tmp)
351 goto out;
352
353 ESP_SKB_CB(skb)->tmp = tmp;
354 iv = esp_tmp_iv(aead, tmp);
355 req = esp_tmp_req(aead, iv);
356 asg = esp_req_sg(aead, req);
357 sg = asg + 1;
358
359 skb->ip_summed = CHECKSUM_NONE;
360
361 esph = (struct ip_esp_hdr *)skb->data;
362
363 /* Get ivec. This can be wrong, check against another impls. */
364 iv = esph->enc_data;
365
366 sg_init_table(sg, nfrags);
367 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
368 sg_init_one(asg, esph, sizeof(*esph));
369
370 aead_request_set_callback(req, 0, esp_input_done, skb);
371 aead_request_set_crypt(req, sg, sg, elen, iv);
372 aead_request_set_assoc(req, asg, sizeof(*esph));
373
374 err = crypto_aead_decrypt(req);
375 if (err == -EINPROGRESS)
376 goto out;
377
378 err = esp_input_done2(skb, err);
379
380 out:
381 return err;
382 }
383
384 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
385 {
386 struct esp_data *esp = x->data;
387 u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
388 u32 align = max_t(u32, blksize, esp->padlen);
389 u32 rem;
390
391 mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
392 rem = mtu & (align - 1);
393 mtu &= ~(align - 1);
394
395 switch (x->props.mode) {
396 case XFRM_MODE_TUNNEL:
397 break;
398 default:
399 case XFRM_MODE_TRANSPORT:
400 /* The worst case */
401 mtu -= blksize - 4;
402 mtu += min_t(u32, blksize - 4, rem);
403 break;
404 case XFRM_MODE_BEET:
405 /* The worst case. */
406 mtu += min_t(u32, IPV4_BEET_PHMAXLEN, rem);
407 break;
408 }
409
410 return mtu - 2;
411 }
412
413 static void esp4_err(struct sk_buff *skb, u32 info)
414 {
415 struct iphdr *iph = (struct iphdr*)skb->data;
416 struct ip_esp_hdr *esph = (struct ip_esp_hdr*)(skb->data+(iph->ihl<<2));
417 struct xfrm_state *x;
418
419 if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
420 icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
421 return;
422
423 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
424 if (!x)
425 return;
426 NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
427 ntohl(esph->spi), ntohl(iph->daddr));
428 xfrm_state_put(x);
429 }
430
431 static void esp_destroy(struct xfrm_state *x)
432 {
433 struct esp_data *esp = x->data;
434
435 if (!esp)
436 return;
437
438 crypto_free_aead(esp->aead);
439 kfree(esp);
440 }
441
442 static int esp_init_aead(struct xfrm_state *x)
443 {
444 struct esp_data *esp = x->data;
445 struct crypto_aead *aead;
446 int err;
447
448 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
449 err = PTR_ERR(aead);
450 if (IS_ERR(aead))
451 goto error;
452
453 esp->aead = aead;
454
455 err = crypto_aead_setkey(aead, x->aead->alg_key,
456 (x->aead->alg_key_len + 7) / 8);
457 if (err)
458 goto error;
459
460 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
461 if (err)
462 goto error;
463
464 error:
465 return err;
466 }
467
468 static int esp_init_authenc(struct xfrm_state *x)
469 {
470 struct esp_data *esp = x->data;
471 struct crypto_aead *aead;
472 struct crypto_authenc_key_param *param;
473 struct rtattr *rta;
474 char *key;
475 char *p;
476 char authenc_name[CRYPTO_MAX_ALG_NAME];
477 unsigned int keylen;
478 int err;
479
480 err = -EINVAL;
481 if (x->ealg == NULL)
482 goto error;
483
484 err = -ENAMETOOLONG;
485 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, "authenc(%s,%s)",
486 x->aalg ? x->aalg->alg_name : "digest_null",
487 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
488 goto error;
489
490 aead = crypto_alloc_aead(authenc_name, 0, 0);
491 err = PTR_ERR(aead);
492 if (IS_ERR(aead))
493 goto error;
494
495 esp->aead = aead;
496
497 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
498 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
499 err = -ENOMEM;
500 key = kmalloc(keylen, GFP_KERNEL);
501 if (!key)
502 goto error;
503
504 p = key;
505 rta = (void *)p;
506 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
507 rta->rta_len = RTA_LENGTH(sizeof(*param));
508 param = RTA_DATA(rta);
509 p += RTA_SPACE(sizeof(*param));
510
511 if (x->aalg) {
512 struct xfrm_algo_desc *aalg_desc;
513
514 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
515 p += (x->aalg->alg_key_len + 7) / 8;
516
517 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
518 BUG_ON(!aalg_desc);
519
520 err = -EINVAL;
521 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
522 crypto_aead_authsize(aead)) {
523 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
524 x->aalg->alg_name,
525 crypto_aead_authsize(aead),
526 aalg_desc->uinfo.auth.icv_fullbits/8);
527 goto free_key;
528 }
529
530 err = crypto_aead_setauthsize(
531 aead, aalg_desc->uinfo.auth.icv_truncbits / 8);
532 if (err)
533 goto free_key;
534 }
535
536 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
537 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
538
539 err = crypto_aead_setkey(aead, key, keylen);
540
541 free_key:
542 kfree(key);
543
544 error:
545 return err;
546 }
547
548 static int esp_init_state(struct xfrm_state *x)
549 {
550 struct esp_data *esp;
551 struct crypto_aead *aead;
552 u32 align;
553 int err;
554
555 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
556 if (esp == NULL)
557 return -ENOMEM;
558
559 x->data = esp;
560
561 if (x->aead)
562 err = esp_init_aead(x);
563 else
564 err = esp_init_authenc(x);
565
566 if (err)
567 goto error;
568
569 aead = esp->aead;
570
571 esp->padlen = 0;
572
573 x->props.header_len = sizeof(struct ip_esp_hdr) +
574 crypto_aead_ivsize(aead);
575 if (x->props.mode == XFRM_MODE_TUNNEL)
576 x->props.header_len += sizeof(struct iphdr);
577 else if (x->props.mode == XFRM_MODE_BEET)
578 x->props.header_len += IPV4_BEET_PHMAXLEN;
579 if (x->encap) {
580 struct xfrm_encap_tmpl *encap = x->encap;
581
582 switch (encap->encap_type) {
583 default:
584 goto error;
585 case UDP_ENCAP_ESPINUDP:
586 x->props.header_len += sizeof(struct udphdr);
587 break;
588 case UDP_ENCAP_ESPINUDP_NON_IKE:
589 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
590 break;
591 }
592 }
593
594 align = ALIGN(crypto_aead_blocksize(aead), 4);
595 if (esp->padlen)
596 align = max_t(u32, align, esp->padlen);
597 x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
598
599 error:
600 return err;
601 }
602
603 static const struct xfrm_type esp_type =
604 {
605 .description = "ESP4",
606 .owner = THIS_MODULE,
607 .proto = IPPROTO_ESP,
608 .flags = XFRM_TYPE_REPLAY_PROT,
609 .init_state = esp_init_state,
610 .destructor = esp_destroy,
611 .get_mtu = esp4_get_mtu,
612 .input = esp_input,
613 .output = esp_output
614 };
615
616 static struct net_protocol esp4_protocol = {
617 .handler = xfrm4_rcv,
618 .err_handler = esp4_err,
619 .no_policy = 1,
620 };
621
622 static int __init esp4_init(void)
623 {
624 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
625 printk(KERN_INFO "ip esp init: can't add xfrm type\n");
626 return -EAGAIN;
627 }
628 if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
629 printk(KERN_INFO "ip esp init: can't add protocol\n");
630 xfrm_unregister_type(&esp_type, AF_INET);
631 return -EAGAIN;
632 }
633 return 0;
634 }
635
636 static void __exit esp4_fini(void)
637 {
638 if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
639 printk(KERN_INFO "ip esp close: can't remove protocol\n");
640 if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
641 printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
642 }
643
644 module_init(esp4_init);
645 module_exit(esp4_fini);
646 MODULE_LICENSE("GPL");
647 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
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