1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27#include <crypto/aead.h>
28#include <crypto/authenc.h>
29#include <linux/err.h>
30#include <linux/module.h>
31#include <net/ip.h>
32#include <net/xfrm.h>
33#include <net/esp.h>
34#include <linux/scatterlist.h>
35#include <linux/kernel.h>
36#include <linux/pfkeyv2.h>
37#include <linux/random.h>
38#include <linux/slab.h>
39#include <linux/spinlock.h>
40#include <net/icmp.h>
41#include <net/ipv6.h>
42#include <net/protocol.h>
43#include <linux/icmpv6.h>
44
45struct esp_skb_cb {
46 struct xfrm_skb_cb xfrm;
47 void *tmp;
48};
49
50#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
51
52
53
54
55
56
57
58
59
60static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags)
61{
62 unsigned int len;
63
64 len = crypto_aead_ivsize(aead);
65 if (len) {
66 len += crypto_aead_alignmask(aead) &
67 ~(crypto_tfm_ctx_alignment() - 1);
68 len = ALIGN(len, crypto_tfm_ctx_alignment());
69 }
70
71 len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
72 len = ALIGN(len, __alignof__(struct scatterlist));
73
74 len += sizeof(struct scatterlist) * nfrags;
75
76 return kmalloc(len, GFP_ATOMIC);
77}
78
79static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp)
80{
81 return crypto_aead_ivsize(aead) ?
82 PTR_ALIGN((u8 *)tmp, crypto_aead_alignmask(aead) + 1) : tmp;
83}
84
85static inline struct aead_givcrypt_request *esp_tmp_givreq(
86 struct crypto_aead *aead, u8 *iv)
87{
88 struct aead_givcrypt_request *req;
89
90 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
91 crypto_tfm_ctx_alignment());
92 aead_givcrypt_set_tfm(req, aead);
93 return req;
94}
95
96static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
97{
98 struct aead_request *req;
99
100 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
101 crypto_tfm_ctx_alignment());
102 aead_request_set_tfm(req, aead);
103 return req;
104}
105
106static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
107 struct aead_request *req)
108{
109 return (void *)ALIGN((unsigned long)(req + 1) +
110 crypto_aead_reqsize(aead),
111 __alignof__(struct scatterlist));
112}
113
114static inline struct scatterlist *esp_givreq_sg(
115 struct crypto_aead *aead, struct aead_givcrypt_request *req)
116{
117 return (void *)ALIGN((unsigned long)(req + 1) +
118 crypto_aead_reqsize(aead),
119 __alignof__(struct scatterlist));
120}
121
122static void esp_output_done(struct crypto_async_request *base, int err)
123{
124 struct sk_buff *skb = base->data;
125
126 kfree(ESP_SKB_CB(skb)->tmp);
127 xfrm_output_resume(skb, err);
128}
129
130static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
131{
132 int err;
133 struct ip_esp_hdr *esph;
134 struct crypto_aead *aead;
135 struct aead_givcrypt_request *req;
136 struct scatterlist *sg;
137 struct scatterlist *asg;
138 struct sk_buff *trailer;
139 void *tmp;
140 int blksize;
141 int clen;
142 int alen;
143 int nfrags;
144 u8 *iv;
145 u8 *tail;
146 struct esp_data *esp = x->data;
147
148
149 err = -ENOMEM;
150
151
152 clen = skb->len;
153
154 aead = esp->aead;
155 alen = crypto_aead_authsize(aead);
156
157 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
158 clen = ALIGN(clen + 2, blksize);
159 if (esp->padlen)
160 clen = ALIGN(clen, esp->padlen);
161
162 if ((err = skb_cow_data(skb, clen - skb->len + alen, &trailer)) < 0)
163 goto error;
164 nfrags = err;
165
166 tmp = esp_alloc_tmp(aead, nfrags + 1);
167 if (!tmp)
168 goto error;
169
170 iv = esp_tmp_iv(aead, tmp);
171 req = esp_tmp_givreq(aead, iv);
172 asg = esp_givreq_sg(aead, req);
173 sg = asg + 1;
174
175
176 tail = skb_tail_pointer(trailer);
177 do {
178 int i;
179 for (i=0; i<clen-skb->len - 2; i++)
180 tail[i] = i + 1;
181 } while (0);
182 tail[clen-skb->len - 2] = (clen - skb->len) - 2;
183 tail[clen - skb->len - 1] = *skb_mac_header(skb);
184 pskb_put(skb, trailer, clen - skb->len + alen);
185
186 skb_push(skb, -skb_network_offset(skb));
187 esph = ip_esp_hdr(skb);
188 *skb_mac_header(skb) = IPPROTO_ESP;
189
190 esph->spi = x->id.spi;
191 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output);
192
193 sg_init_table(sg, nfrags);
194 skb_to_sgvec(skb, sg,
195 esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
196 clen + alen);
197 sg_init_one(asg, esph, sizeof(*esph));
198
199 aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
200 aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
201 aead_givcrypt_set_assoc(req, asg, sizeof(*esph));
202 aead_givcrypt_set_giv(req, esph->enc_data,
203 XFRM_SKB_CB(skb)->seq.output);
204
205 ESP_SKB_CB(skb)->tmp = tmp;
206 err = crypto_aead_givencrypt(req);
207 if (err == -EINPROGRESS)
208 goto error;
209
210 if (err == -EBUSY)
211 err = NET_XMIT_DROP;
212
213 kfree(tmp);
214
215error:
216 return err;
217}
218
219static int esp_input_done2(struct sk_buff *skb, int err)
220{
221 struct xfrm_state *x = xfrm_input_state(skb);
222 struct esp_data *esp = x->data;
223 struct crypto_aead *aead = esp->aead;
224 int alen = crypto_aead_authsize(aead);
225 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
226 int elen = skb->len - hlen;
227 int hdr_len = skb_network_header_len(skb);
228 int padlen;
229 u8 nexthdr[2];
230
231 kfree(ESP_SKB_CB(skb)->tmp);
232
233 if (unlikely(err))
234 goto out;
235
236 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
237 BUG();
238
239 err = -EINVAL;
240 padlen = nexthdr[0];
241 if (padlen + 2 + alen >= elen) {
242 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage "
243 "padlen=%d, elen=%d\n", padlen + 2, elen - alen);
244 goto out;
245 }
246
247
248
249 pskb_trim(skb, skb->len - alen - padlen - 2);
250 __skb_pull(skb, hlen);
251 skb_set_transport_header(skb, -hdr_len);
252
253 err = nexthdr[1];
254
255
256 if (err == IPPROTO_NONE)
257 err = -EINVAL;
258
259out:
260 return err;
261}
262
263static void esp_input_done(struct crypto_async_request *base, int err)
264{
265 struct sk_buff *skb = base->data;
266
267 xfrm_input_resume(skb, esp_input_done2(skb, err));
268}
269
270static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
271{
272 struct ip_esp_hdr *esph;
273 struct esp_data *esp = x->data;
274 struct crypto_aead *aead = esp->aead;
275 struct aead_request *req;
276 struct sk_buff *trailer;
277 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
278 int nfrags;
279 int ret = 0;
280 void *tmp;
281 u8 *iv;
282 struct scatterlist *sg;
283 struct scatterlist *asg;
284
285 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
286 ret = -EINVAL;
287 goto out;
288 }
289
290 if (elen <= 0) {
291 ret = -EINVAL;
292 goto out;
293 }
294
295 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
296 ret = -EINVAL;
297 goto out;
298 }
299
300 ret = -ENOMEM;
301 tmp = esp_alloc_tmp(aead, nfrags + 1);
302 if (!tmp)
303 goto out;
304
305 ESP_SKB_CB(skb)->tmp = tmp;
306 iv = esp_tmp_iv(aead, tmp);
307 req = esp_tmp_req(aead, iv);
308 asg = esp_req_sg(aead, req);
309 sg = asg + 1;
310
311 skb->ip_summed = CHECKSUM_NONE;
312
313 esph = (struct ip_esp_hdr *)skb->data;
314
315
316 iv = esph->enc_data;
317
318 sg_init_table(sg, nfrags);
319 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
320 sg_init_one(asg, esph, sizeof(*esph));
321
322 aead_request_set_callback(req, 0, esp_input_done, skb);
323 aead_request_set_crypt(req, sg, sg, elen, iv);
324 aead_request_set_assoc(req, asg, sizeof(*esph));
325
326 ret = crypto_aead_decrypt(req);
327 if (ret == -EINPROGRESS)
328 goto out;
329
330 ret = esp_input_done2(skb, ret);
331
332out:
333 return ret;
334}
335
336static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
337{
338 struct esp_data *esp = x->data;
339 u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
340 u32 align = max_t(u32, blksize, esp->padlen);
341 u32 rem;
342
343 mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
344 rem = mtu & (align - 1);
345 mtu &= ~(align - 1);
346
347 if (x->props.mode != XFRM_MODE_TUNNEL) {
348 u32 padsize = ((blksize - 1) & 7) + 1;
349 mtu -= blksize - padsize;
350 mtu += min_t(u32, blksize - padsize, rem);
351 }
352
353 return mtu - 2;
354}
355
356static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
357 int type, int code, int offset, __be32 info)
358{
359 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
360 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
361 struct xfrm_state *x;
362
363 if (type != ICMPV6_DEST_UNREACH &&
364 type != ICMPV6_PKT_TOOBIG)
365 return;
366
367 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
368 if (!x)
369 return;
370 printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n",
371 ntohl(esph->spi), NIP6(iph->daddr));
372 xfrm_state_put(x);
373}
374
375static void esp6_destroy(struct xfrm_state *x)
376{
377 struct esp_data *esp = x->data;
378
379 if (!esp)
380 return;
381
382 crypto_free_aead(esp->aead);
383 kfree(esp);
384}
385
386static int esp_init_aead(struct xfrm_state *x)
387{
388 struct esp_data *esp = x->data;
389 struct crypto_aead *aead;
390 int err;
391
392 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
393 err = PTR_ERR(aead);
394 if (IS_ERR(aead))
395 goto error;
396
397 esp->aead = aead;
398
399 err = crypto_aead_setkey(aead, x->aead->alg_key,
400 (x->aead->alg_key_len + 7) / 8);
401 if (err)
402 goto error;
403
404 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
405 if (err)
406 goto error;
407
408error:
409 return err;
410}
411
412static int esp_init_authenc(struct xfrm_state *x)
413{
414 struct esp_data *esp = x->data;
415 struct crypto_aead *aead;
416 struct crypto_authenc_key_param *param;
417 struct rtattr *rta;
418 char *key;
419 char *p;
420 char authenc_name[CRYPTO_MAX_ALG_NAME];
421 unsigned int keylen;
422 int err;
423
424 err = -EINVAL;
425 if (x->ealg == NULL)
426 goto error;
427
428 err = -ENAMETOOLONG;
429 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME, "authenc(%s,%s)",
430 x->aalg ? x->aalg->alg_name : "digest_null",
431 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
432 goto error;
433
434 aead = crypto_alloc_aead(authenc_name, 0, 0);
435 err = PTR_ERR(aead);
436 if (IS_ERR(aead))
437 goto error;
438
439 esp->aead = aead;
440
441 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
442 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
443 err = -ENOMEM;
444 key = kmalloc(keylen, GFP_KERNEL);
445 if (!key)
446 goto error;
447
448 p = key;
449 rta = (void *)p;
450 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
451 rta->rta_len = RTA_LENGTH(sizeof(*param));
452 param = RTA_DATA(rta);
453 p += RTA_SPACE(sizeof(*param));
454
455 if (x->aalg) {
456 struct xfrm_algo_desc *aalg_desc;
457
458 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
459 p += (x->aalg->alg_key_len + 7) / 8;
460
461 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
462 BUG_ON(!aalg_desc);
463
464 err = -EINVAL;
465 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
466 crypto_aead_authsize(aead)) {
467 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
468 x->aalg->alg_name,
469 crypto_aead_authsize(aead),
470 aalg_desc->uinfo.auth.icv_fullbits/8);
471 goto free_key;
472 }
473
474 err = crypto_aead_setauthsize(
475 aead, aalg_desc->uinfo.auth.icv_truncbits / 8);
476 if (err)
477 goto free_key;
478 }
479
480 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
481 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
482
483 err = crypto_aead_setkey(aead, key, keylen);
484
485free_key:
486 kfree(key);
487
488error:
489 return err;
490}
491
492static int esp6_init_state(struct xfrm_state *x)
493{
494 struct esp_data *esp;
495 struct crypto_aead *aead;
496 u32 align;
497 int err;
498
499 if (x->encap)
500 return -EINVAL;
501
502 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
503 if (esp == NULL)
504 return -ENOMEM;
505
506 x->data = esp;
507
508 if (x->aead)
509 err = esp_init_aead(x);
510 else
511 err = esp_init_authenc(x);
512
513 if (err)
514 goto error;
515
516 aead = esp->aead;
517
518 esp->padlen = 0;
519
520 x->props.header_len = sizeof(struct ip_esp_hdr) +
521 crypto_aead_ivsize(aead);
522 switch (x->props.mode) {
523 case XFRM_MODE_BEET:
524 if (x->sel.family != AF_INET6)
525 x->props.header_len += IPV4_BEET_PHMAXLEN +
526 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
527 break;
528 case XFRM_MODE_TRANSPORT:
529 break;
530 case XFRM_MODE_TUNNEL:
531 x->props.header_len += sizeof(struct ipv6hdr);
532 break;
533 default:
534 goto error;
535 }
536
537 align = ALIGN(crypto_aead_blocksize(aead), 4);
538 if (esp->padlen)
539 align = max_t(u32, align, esp->padlen);
540 x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
541
542error:
543 return err;
544}
545
546static const struct xfrm_type esp6_type =
547{
548 .description = "ESP6",
549 .owner = THIS_MODULE,
550 .proto = IPPROTO_ESP,
551 .flags = XFRM_TYPE_REPLAY_PROT,
552 .init_state = esp6_init_state,
553 .destructor = esp6_destroy,
554 .get_mtu = esp6_get_mtu,
555 .input = esp6_input,
556 .output = esp6_output,
557 .hdr_offset = xfrm6_find_1stfragopt,
558};
559
560static struct inet6_protocol esp6_protocol = {
561 .handler = xfrm6_rcv,
562 .err_handler = esp6_err,
563 .flags = INET6_PROTO_NOPOLICY,
564};
565
566static int __init esp6_init(void)
567{
568 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
569 printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
570 return -EAGAIN;
571 }
572 if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
573 printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
574 xfrm_unregister_type(&esp6_type, AF_INET6);
575 return -EAGAIN;
576 }
577
578 return 0;
579}
580
581static void __exit esp6_fini(void)
582{
583 if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
584 printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
585 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
586 printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
587}
588
589module_init(esp6_init);
590module_exit(esp6_fini);
591
592MODULE_LICENSE("GPL");
593MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
594
