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27#define pr_fmt(fmt) "IPv6: " fmt
28
29#include <crypto/aead.h>
30#include <crypto/authenc.h>
31#include <linux/err.h>
32#include <linux/module.h>
33#include <net/ip.h>
34#include <net/xfrm.h>
35#include <net/esp.h>
36#include <linux/scatterlist.h>
37#include <linux/kernel.h>
38#include <linux/pfkeyv2.h>
39#include <linux/random.h>
40#include <linux/slab.h>
41#include <linux/spinlock.h>
42#include <net/ip6_route.h>
43#include <net/icmp.h>
44#include <net/ipv6.h>
45#include <net/protocol.h>
46#include <linux/icmpv6.h>
47
48struct esp_skb_cb {
49 struct xfrm_skb_cb xfrm;
50 void *tmp;
51};
52
53#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
54
55static u32 esp6_get_mtu(struct xfrm_state *x, int mtu);
56
57
58
59
60
61
62
63
64
65
66static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
67{
68 unsigned int len;
69
70 len = seqihlen;
71
72 len += crypto_aead_ivsize(aead);
73
74 if (len) {
75 len += crypto_aead_alignmask(aead) &
76 ~(crypto_tfm_ctx_alignment() - 1);
77 len = ALIGN(len, crypto_tfm_ctx_alignment());
78 }
79
80 len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
81 len = ALIGN(len, __alignof__(struct scatterlist));
82
83 len += sizeof(struct scatterlist) * nfrags;
84
85 return kmalloc(len, GFP_ATOMIC);
86}
87
88static inline __be32 *esp_tmp_seqhi(void *tmp)
89{
90 return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
91}
92
93static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
94{
95 return crypto_aead_ivsize(aead) ?
96 PTR_ALIGN((u8 *)tmp + seqhilen,
97 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
98}
99
100static inline struct aead_givcrypt_request *esp_tmp_givreq(
101 struct crypto_aead *aead, u8 *iv)
102{
103 struct aead_givcrypt_request *req;
104
105 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
106 crypto_tfm_ctx_alignment());
107 aead_givcrypt_set_tfm(req, aead);
108 return req;
109}
110
111static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
112{
113 struct aead_request *req;
114
115 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
116 crypto_tfm_ctx_alignment());
117 aead_request_set_tfm(req, aead);
118 return req;
119}
120
121static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
122 struct aead_request *req)
123{
124 return (void *)ALIGN((unsigned long)(req + 1) +
125 crypto_aead_reqsize(aead),
126 __alignof__(struct scatterlist));
127}
128
129static inline struct scatterlist *esp_givreq_sg(
130 struct crypto_aead *aead, struct aead_givcrypt_request *req)
131{
132 return (void *)ALIGN((unsigned long)(req + 1) +
133 crypto_aead_reqsize(aead),
134 __alignof__(struct scatterlist));
135}
136
137static void esp_output_done(struct crypto_async_request *base, int err)
138{
139 struct sk_buff *skb = base->data;
140
141 kfree(ESP_SKB_CB(skb)->tmp);
142 xfrm_output_resume(skb, err);
143}
144
145static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
146{
147 int err;
148 struct ip_esp_hdr *esph;
149 struct crypto_aead *aead;
150 struct aead_givcrypt_request *req;
151 struct scatterlist *sg;
152 struct scatterlist *asg;
153 struct sk_buff *trailer;
154 void *tmp;
155 int blksize;
156 int clen;
157 int alen;
158 int plen;
159 int tfclen;
160 int nfrags;
161 int assoclen;
162 int sglists;
163 int seqhilen;
164 u8 *iv;
165 u8 *tail;
166 __be32 *seqhi;
167 struct esp_data *esp = x->data;
168
169
170 aead = esp->aead;
171 alen = crypto_aead_authsize(aead);
172
173 tfclen = 0;
174 if (x->tfcpad) {
175 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
176 u32 padto;
177
178 padto = min(x->tfcpad, esp6_get_mtu(x, dst->child_mtu_cached));
179 if (skb->len < padto)
180 tfclen = padto - skb->len;
181 }
182 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
183 clen = ALIGN(skb->len + 2 + tfclen, blksize);
184 if (esp->padlen)
185 clen = ALIGN(clen, esp->padlen);
186 plen = clen - skb->len - tfclen;
187
188 err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
189 if (err < 0)
190 goto error;
191 nfrags = err;
192
193 assoclen = sizeof(*esph);
194 sglists = 1;
195 seqhilen = 0;
196
197 if (x->props.flags & XFRM_STATE_ESN) {
198 sglists += 2;
199 seqhilen += sizeof(__be32);
200 assoclen += seqhilen;
201 }
202
203 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
204 if (!tmp) {
205 err = -ENOMEM;
206 goto error;
207 }
208
209 seqhi = esp_tmp_seqhi(tmp);
210 iv = esp_tmp_iv(aead, tmp, seqhilen);
211 req = esp_tmp_givreq(aead, iv);
212 asg = esp_givreq_sg(aead, req);
213 sg = asg + sglists;
214
215
216 tail = skb_tail_pointer(trailer);
217 if (tfclen) {
218 memset(tail, 0, tfclen);
219 tail += tfclen;
220 }
221 do {
222 int i;
223 for (i = 0; i < plen - 2; i++)
224 tail[i] = i + 1;
225 } while (0);
226 tail[plen - 2] = plen - 2;
227 tail[plen - 1] = *skb_mac_header(skb);
228 pskb_put(skb, trailer, clen - skb->len + alen);
229
230 skb_push(skb, -skb_network_offset(skb));
231 esph = ip_esp_hdr(skb);
232 *skb_mac_header(skb) = IPPROTO_ESP;
233
234 esph->spi = x->id.spi;
235 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
236
237 sg_init_table(sg, nfrags);
238 skb_to_sgvec(skb, sg,
239 esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
240 clen + alen);
241
242 if ((x->props.flags & XFRM_STATE_ESN)) {
243 sg_init_table(asg, 3);
244 sg_set_buf(asg, &esph->spi, sizeof(__be32));
245 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
246 sg_set_buf(asg + 1, seqhi, seqhilen);
247 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
248 } else
249 sg_init_one(asg, esph, sizeof(*esph));
250
251 aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
252 aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
253 aead_givcrypt_set_assoc(req, asg, assoclen);
254 aead_givcrypt_set_giv(req, esph->enc_data,
255 XFRM_SKB_CB(skb)->seq.output.low);
256
257 ESP_SKB_CB(skb)->tmp = tmp;
258 err = crypto_aead_givencrypt(req);
259 if (err == -EINPROGRESS)
260 goto error;
261
262 if (err == -EBUSY)
263 err = NET_XMIT_DROP;
264
265 kfree(tmp);
266
267error:
268 return err;
269}
270
271static int esp_input_done2(struct sk_buff *skb, int err)
272{
273 struct xfrm_state *x = xfrm_input_state(skb);
274 struct esp_data *esp = x->data;
275 struct crypto_aead *aead = esp->aead;
276 int alen = crypto_aead_authsize(aead);
277 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
278 int elen = skb->len - hlen;
279 int hdr_len = skb_network_header_len(skb);
280 int padlen;
281 u8 nexthdr[2];
282
283 kfree(ESP_SKB_CB(skb)->tmp);
284
285 if (unlikely(err))
286 goto out;
287
288 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
289 BUG();
290
291 err = -EINVAL;
292 padlen = nexthdr[0];
293 if (padlen + 2 + alen >= elen) {
294 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage "
295 "padlen=%d, elen=%d\n", padlen + 2, elen - alen);
296 goto out;
297 }
298
299
300
301 pskb_trim(skb, skb->len - alen - padlen - 2);
302 __skb_pull(skb, hlen);
303 if (x->props.mode == XFRM_MODE_TUNNEL)
304 skb_reset_transport_header(skb);
305 else
306 skb_set_transport_header(skb, -hdr_len);
307
308 err = nexthdr[1];
309
310
311 if (err == IPPROTO_NONE)
312 err = -EINVAL;
313
314out:
315 return err;
316}
317
318static void esp_input_done(struct crypto_async_request *base, int err)
319{
320 struct sk_buff *skb = base->data;
321
322 xfrm_input_resume(skb, esp_input_done2(skb, err));
323}
324
325static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
326{
327 struct ip_esp_hdr *esph;
328 struct esp_data *esp = x->data;
329 struct crypto_aead *aead = esp->aead;
330 struct aead_request *req;
331 struct sk_buff *trailer;
332 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
333 int nfrags;
334 int assoclen;
335 int sglists;
336 int seqhilen;
337 int ret = 0;
338 void *tmp;
339 __be32 *seqhi;
340 u8 *iv;
341 struct scatterlist *sg;
342 struct scatterlist *asg;
343
344 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
345 ret = -EINVAL;
346 goto out;
347 }
348
349 if (elen <= 0) {
350 ret = -EINVAL;
351 goto out;
352 }
353
354 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
355 ret = -EINVAL;
356 goto out;
357 }
358
359 ret = -ENOMEM;
360
361 assoclen = sizeof(*esph);
362 sglists = 1;
363 seqhilen = 0;
364
365 if (x->props.flags & XFRM_STATE_ESN) {
366 sglists += 2;
367 seqhilen += sizeof(__be32);
368 assoclen += seqhilen;
369 }
370
371 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
372 if (!tmp)
373 goto out;
374
375 ESP_SKB_CB(skb)->tmp = tmp;
376 seqhi = esp_tmp_seqhi(tmp);
377 iv = esp_tmp_iv(aead, tmp, seqhilen);
378 req = esp_tmp_req(aead, iv);
379 asg = esp_req_sg(aead, req);
380 sg = asg + sglists;
381
382 skb->ip_summed = CHECKSUM_NONE;
383
384 esph = (struct ip_esp_hdr *)skb->data;
385
386
387 iv = esph->enc_data;
388
389 sg_init_table(sg, nfrags);
390 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
391
392 if ((x->props.flags & XFRM_STATE_ESN)) {
393 sg_init_table(asg, 3);
394 sg_set_buf(asg, &esph->spi, sizeof(__be32));
395 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
396 sg_set_buf(asg + 1, seqhi, seqhilen);
397 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
398 } else
399 sg_init_one(asg, esph, sizeof(*esph));
400
401 aead_request_set_callback(req, 0, esp_input_done, skb);
402 aead_request_set_crypt(req, sg, sg, elen, iv);
403 aead_request_set_assoc(req, asg, assoclen);
404
405 ret = crypto_aead_decrypt(req);
406 if (ret == -EINPROGRESS)
407 goto out;
408
409 ret = esp_input_done2(skb, ret);
410
411out:
412 return ret;
413}
414
415static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
416{
417 struct esp_data *esp = x->data;
418 u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
419 u32 align = max_t(u32, blksize, esp->padlen);
420 unsigned int net_adj;
421
422 if (x->props.mode != XFRM_MODE_TUNNEL)
423 net_adj = sizeof(struct ipv6hdr);
424 else
425 net_adj = 0;
426
427 return ((mtu - x->props.header_len - crypto_aead_authsize(esp->aead) -
428 net_adj) & ~(align - 1)) + (net_adj - 2);
429}
430
431static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
432 u8 type, u8 code, int offset, __be32 info)
433{
434 struct net *net = dev_net(skb->dev);
435 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
436 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
437 struct xfrm_state *x;
438
439 if (type != ICMPV6_DEST_UNREACH &&
440 type != ICMPV6_PKT_TOOBIG &&
441 type != NDISC_REDIRECT)
442 return;
443
444 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
445 esph->spi, IPPROTO_ESP, AF_INET6);
446 if (!x)
447 return;
448
449 if (type == NDISC_REDIRECT)
450 ip6_redirect(skb, net, 0, 0);
451 else
452 ip6_update_pmtu(skb, net, info, 0, 0);
453 xfrm_state_put(x);
454}
455
456static void esp6_destroy(struct xfrm_state *x)
457{
458 struct esp_data *esp = x->data;
459
460 if (!esp)
461 return;
462
463 crypto_free_aead(esp->aead);
464 kfree(esp);
465}
466
467static int esp_init_aead(struct xfrm_state *x)
468{
469 struct esp_data *esp = x->data;
470 struct crypto_aead *aead;
471 int err;
472
473 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
474 err = PTR_ERR(aead);
475 if (IS_ERR(aead))
476 goto error;
477
478 esp->aead = aead;
479
480 err = crypto_aead_setkey(aead, x->aead->alg_key,
481 (x->aead->alg_key_len + 7) / 8);
482 if (err)
483 goto error;
484
485 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
486 if (err)
487 goto error;
488
489error:
490 return err;
491}
492
493static int esp_init_authenc(struct xfrm_state *x)
494{
495 struct esp_data *esp = x->data;
496 struct crypto_aead *aead;
497 struct crypto_authenc_key_param *param;
498 struct rtattr *rta;
499 char *key;
500 char *p;
501 char authenc_name[CRYPTO_MAX_ALG_NAME];
502 unsigned int keylen;
503 int err;
504
505 err = -EINVAL;
506 if (x->ealg == NULL)
507 goto error;
508
509 err = -ENAMETOOLONG;
510
511 if ((x->props.flags & XFRM_STATE_ESN)) {
512 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
513 "authencesn(%s,%s)",
514 x->aalg ? x->aalg->alg_name : "digest_null",
515 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
516 goto error;
517 } else {
518 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
519 "authenc(%s,%s)",
520 x->aalg ? x->aalg->alg_name : "digest_null",
521 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
522 goto error;
523 }
524
525 aead = crypto_alloc_aead(authenc_name, 0, 0);
526 err = PTR_ERR(aead);
527 if (IS_ERR(aead))
528 goto error;
529
530 esp->aead = aead;
531
532 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
533 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
534 err = -ENOMEM;
535 key = kmalloc(keylen, GFP_KERNEL);
536 if (!key)
537 goto error;
538
539 p = key;
540 rta = (void *)p;
541 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
542 rta->rta_len = RTA_LENGTH(sizeof(*param));
543 param = RTA_DATA(rta);
544 p += RTA_SPACE(sizeof(*param));
545
546 if (x->aalg) {
547 struct xfrm_algo_desc *aalg_desc;
548
549 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
550 p += (x->aalg->alg_key_len + 7) / 8;
551
552 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
553 BUG_ON(!aalg_desc);
554
555 err = -EINVAL;
556 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
557 crypto_aead_authsize(aead)) {
558 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
559 x->aalg->alg_name,
560 crypto_aead_authsize(aead),
561 aalg_desc->uinfo.auth.icv_fullbits/8);
562 goto free_key;
563 }
564
565 err = crypto_aead_setauthsize(
566 aead, x->aalg->alg_trunc_len / 8);
567 if (err)
568 goto free_key;
569 }
570
571 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
572 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
573
574 err = crypto_aead_setkey(aead, key, keylen);
575
576free_key:
577 kfree(key);
578
579error:
580 return err;
581}
582
583static int esp6_init_state(struct xfrm_state *x)
584{
585 struct esp_data *esp;
586 struct crypto_aead *aead;
587 u32 align;
588 int err;
589
590 if (x->encap)
591 return -EINVAL;
592
593 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
594 if (esp == NULL)
595 return -ENOMEM;
596
597 x->data = esp;
598
599 if (x->aead)
600 err = esp_init_aead(x);
601 else
602 err = esp_init_authenc(x);
603
604 if (err)
605 goto error;
606
607 aead = esp->aead;
608
609 esp->padlen = 0;
610
611 x->props.header_len = sizeof(struct ip_esp_hdr) +
612 crypto_aead_ivsize(aead);
613 switch (x->props.mode) {
614 case XFRM_MODE_BEET:
615 if (x->sel.family != AF_INET6)
616 x->props.header_len += IPV4_BEET_PHMAXLEN +
617 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
618 break;
619 case XFRM_MODE_TRANSPORT:
620 break;
621 case XFRM_MODE_TUNNEL:
622 x->props.header_len += sizeof(struct ipv6hdr);
623 break;
624 default:
625 goto error;
626 }
627
628 align = ALIGN(crypto_aead_blocksize(aead), 4);
629 if (esp->padlen)
630 align = max_t(u32, align, esp->padlen);
631 x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
632
633error:
634 return err;
635}
636
637static const struct xfrm_type esp6_type =
638{
639 .description = "ESP6",
640 .owner = THIS_MODULE,
641 .proto = IPPROTO_ESP,
642 .flags = XFRM_TYPE_REPLAY_PROT,
643 .init_state = esp6_init_state,
644 .destructor = esp6_destroy,
645 .get_mtu = esp6_get_mtu,
646 .input = esp6_input,
647 .output = esp6_output,
648 .hdr_offset = xfrm6_find_1stfragopt,
649};
650
651static const struct inet6_protocol esp6_protocol = {
652 .handler = xfrm6_rcv,
653 .err_handler = esp6_err,
654 .flags = INET6_PROTO_NOPOLICY,
655};
656
657static int __init esp6_init(void)
658{
659 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
660 pr_info("%s: can't add xfrm type\n", __func__);
661 return -EAGAIN;
662 }
663 if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
664 pr_info("%s: can't add protocol\n", __func__);
665 xfrm_unregister_type(&esp6_type, AF_INET6);
666 return -EAGAIN;
667 }
668
669 return 0;
670}
671
672static void __exit esp6_fini(void)
673{
674 if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
675 pr_info("%s: can't remove protocol\n", __func__);
676 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
677 pr_info("%s: can't remove xfrm type\n", __func__);
678}
679
680module_init(esp6_init);
681module_exit(esp6_fini);
682
683MODULE_LICENSE("GPL");
684MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
685
