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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 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
257
258 ESP_SKB_CB(skb)->tmp = tmp;
259 err = crypto_aead_givencrypt(req);
260 if (err == -EINPROGRESS)
261 goto error;
262
263 if (err == -EBUSY)
264 err = NET_XMIT_DROP;
265
266 kfree(tmp);
267
268error:
269 return err;
270}
271
272static int esp_input_done2(struct sk_buff *skb, int err)
273{
274 struct xfrm_state *x = xfrm_input_state(skb);
275 struct esp_data *esp = x->data;
276 struct crypto_aead *aead = esp->aead;
277 int alen = crypto_aead_authsize(aead);
278 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
279 int elen = skb->len - hlen;
280 int hdr_len = skb_network_header_len(skb);
281 int padlen;
282 u8 nexthdr[2];
283
284 kfree(ESP_SKB_CB(skb)->tmp);
285
286 if (unlikely(err))
287 goto out;
288
289 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
290 BUG();
291
292 err = -EINVAL;
293 padlen = nexthdr[0];
294 if (padlen + 2 + alen >= elen) {
295 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage "
296 "padlen=%d, elen=%d\n", padlen + 2, elen - alen);
297 goto out;
298 }
299
300
301
302 pskb_trim(skb, skb->len - alen - padlen - 2);
303 __skb_pull(skb, hlen);
304 if (x->props.mode == XFRM_MODE_TUNNEL)
305 skb_reset_transport_header(skb);
306 else
307 skb_set_transport_header(skb, -hdr_len);
308
309 err = nexthdr[1];
310
311
312 if (err == IPPROTO_NONE)
313 err = -EINVAL;
314
315out:
316 return err;
317}
318
319static void esp_input_done(struct crypto_async_request *base, int err)
320{
321 struct sk_buff *skb = base->data;
322
323 xfrm_input_resume(skb, esp_input_done2(skb, err));
324}
325
326static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
327{
328 struct ip_esp_hdr *esph;
329 struct esp_data *esp = x->data;
330 struct crypto_aead *aead = esp->aead;
331 struct aead_request *req;
332 struct sk_buff *trailer;
333 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
334 int nfrags;
335 int assoclen;
336 int sglists;
337 int seqhilen;
338 int ret = 0;
339 void *tmp;
340 __be32 *seqhi;
341 u8 *iv;
342 struct scatterlist *sg;
343 struct scatterlist *asg;
344
345 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead))) {
346 ret = -EINVAL;
347 goto out;
348 }
349
350 if (elen <= 0) {
351 ret = -EINVAL;
352 goto out;
353 }
354
355 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
356 ret = -EINVAL;
357 goto out;
358 }
359
360 ret = -ENOMEM;
361
362 assoclen = sizeof(*esph);
363 sglists = 1;
364 seqhilen = 0;
365
366 if (x->props.flags & XFRM_STATE_ESN) {
367 sglists += 2;
368 seqhilen += sizeof(__be32);
369 assoclen += seqhilen;
370 }
371
372 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
373 if (!tmp)
374 goto out;
375
376 ESP_SKB_CB(skb)->tmp = tmp;
377 seqhi = esp_tmp_seqhi(tmp);
378 iv = esp_tmp_iv(aead, tmp, seqhilen);
379 req = esp_tmp_req(aead, iv);
380 asg = esp_req_sg(aead, req);
381 sg = asg + sglists;
382
383 skb->ip_summed = CHECKSUM_NONE;
384
385 esph = (struct ip_esp_hdr *)skb->data;
386
387
388 iv = esph->enc_data;
389
390 sg_init_table(sg, nfrags);
391 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
392
393 if ((x->props.flags & XFRM_STATE_ESN)) {
394 sg_init_table(asg, 3);
395 sg_set_buf(asg, &esph->spi, sizeof(__be32));
396 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
397 sg_set_buf(asg + 1, seqhi, seqhilen);
398 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
399 } else
400 sg_init_one(asg, esph, sizeof(*esph));
401
402 aead_request_set_callback(req, 0, esp_input_done, skb);
403 aead_request_set_crypt(req, sg, sg, elen, iv);
404 aead_request_set_assoc(req, asg, assoclen);
405
406 ret = crypto_aead_decrypt(req);
407 if (ret == -EINPROGRESS)
408 goto out;
409
410 ret = esp_input_done2(skb, ret);
411
412out:
413 return ret;
414}
415
416static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
417{
418 struct esp_data *esp = x->data;
419 u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
420 u32 align = max_t(u32, blksize, esp->padlen);
421 unsigned int net_adj;
422
423 if (x->props.mode != XFRM_MODE_TUNNEL)
424 net_adj = sizeof(struct ipv6hdr);
425 else
426 net_adj = 0;
427
428 return ((mtu - x->props.header_len - crypto_aead_authsize(esp->aead) -
429 net_adj) & ~(align - 1)) + net_adj - 2;
430}
431
432static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
433 u8 type, u8 code, int offset, __be32 info)
434{
435 struct net *net = dev_net(skb->dev);
436 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
437 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
438 struct xfrm_state *x;
439
440 if (type != ICMPV6_PKT_TOOBIG &&
441 type != NDISC_REDIRECT)
442 return 0;
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 0;
448
449 if (type == NDISC_REDIRECT)
450 ip6_redirect(skb, net, skb->dev->ifindex, 0);
451 else
452 ip6_update_pmtu(skb, net, info, 0, 0);
453 xfrm_state_put(x);
454
455 return 0;
456}
457
458static void esp6_destroy(struct xfrm_state *x)
459{
460 struct esp_data *esp = x->data;
461
462 if (!esp)
463 return;
464
465 crypto_free_aead(esp->aead);
466 kfree(esp);
467}
468
469static int esp_init_aead(struct xfrm_state *x)
470{
471 struct esp_data *esp = x->data;
472 struct crypto_aead *aead;
473 int err;
474
475 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
476 err = PTR_ERR(aead);
477 if (IS_ERR(aead))
478 goto error;
479
480 esp->aead = aead;
481
482 err = crypto_aead_setkey(aead, x->aead->alg_key,
483 (x->aead->alg_key_len + 7) / 8);
484 if (err)
485 goto error;
486
487 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
488 if (err)
489 goto error;
490
491error:
492 return err;
493}
494
495static int esp_init_authenc(struct xfrm_state *x)
496{
497 struct esp_data *esp = x->data;
498 struct crypto_aead *aead;
499 struct crypto_authenc_key_param *param;
500 struct rtattr *rta;
501 char *key;
502 char *p;
503 char authenc_name[CRYPTO_MAX_ALG_NAME];
504 unsigned int keylen;
505 int err;
506
507 err = -EINVAL;
508 if (x->ealg == NULL)
509 goto error;
510
511 err = -ENAMETOOLONG;
512
513 if ((x->props.flags & XFRM_STATE_ESN)) {
514 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
515 "authencesn(%s,%s)",
516 x->aalg ? x->aalg->alg_name : "digest_null",
517 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
518 goto error;
519 } else {
520 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
521 "authenc(%s,%s)",
522 x->aalg ? x->aalg->alg_name : "digest_null",
523 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
524 goto error;
525 }
526
527 aead = crypto_alloc_aead(authenc_name, 0, 0);
528 err = PTR_ERR(aead);
529 if (IS_ERR(aead))
530 goto error;
531
532 esp->aead = aead;
533
534 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
535 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
536 err = -ENOMEM;
537 key = kmalloc(keylen, GFP_KERNEL);
538 if (!key)
539 goto error;
540
541 p = key;
542 rta = (void *)p;
543 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
544 rta->rta_len = RTA_LENGTH(sizeof(*param));
545 param = RTA_DATA(rta);
546 p += RTA_SPACE(sizeof(*param));
547
548 if (x->aalg) {
549 struct xfrm_algo_desc *aalg_desc;
550
551 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
552 p += (x->aalg->alg_key_len + 7) / 8;
553
554 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
555 BUG_ON(!aalg_desc);
556
557 err = -EINVAL;
558 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
559 crypto_aead_authsize(aead)) {
560 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
561 x->aalg->alg_name,
562 crypto_aead_authsize(aead),
563 aalg_desc->uinfo.auth.icv_fullbits/8);
564 goto free_key;
565 }
566
567 err = crypto_aead_setauthsize(
568 aead, x->aalg->alg_trunc_len / 8);
569 if (err)
570 goto free_key;
571 }
572
573 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
574 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
575
576 err = crypto_aead_setkey(aead, key, keylen);
577
578free_key:
579 kfree(key);
580
581error:
582 return err;
583}
584
585static int esp6_init_state(struct xfrm_state *x)
586{
587 struct esp_data *esp;
588 struct crypto_aead *aead;
589 u32 align;
590 int err;
591
592 if (x->encap)
593 return -EINVAL;
594
595 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
596 if (esp == NULL)
597 return -ENOMEM;
598
599 x->data = esp;
600
601 if (x->aead)
602 err = esp_init_aead(x);
603 else
604 err = esp_init_authenc(x);
605
606 if (err)
607 goto error;
608
609 aead = esp->aead;
610
611 esp->padlen = 0;
612
613 x->props.header_len = sizeof(struct ip_esp_hdr) +
614 crypto_aead_ivsize(aead);
615 switch (x->props.mode) {
616 case XFRM_MODE_BEET:
617 if (x->sel.family != AF_INET6)
618 x->props.header_len += IPV4_BEET_PHMAXLEN +
619 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
620 break;
621 case XFRM_MODE_TRANSPORT:
622 break;
623 case XFRM_MODE_TUNNEL:
624 x->props.header_len += sizeof(struct ipv6hdr);
625 break;
626 default:
627 goto error;
628 }
629
630 align = ALIGN(crypto_aead_blocksize(aead), 4);
631 if (esp->padlen)
632 align = max_t(u32, align, esp->padlen);
633 x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
634
635error:
636 return err;
637}
638
639static int esp6_rcv_cb(struct sk_buff *skb, int err)
640{
641 return 0;
642}
643
644static const struct xfrm_type esp6_type =
645{
646 .description = "ESP6",
647 .owner = THIS_MODULE,
648 .proto = IPPROTO_ESP,
649 .flags = XFRM_TYPE_REPLAY_PROT,
650 .init_state = esp6_init_state,
651 .destructor = esp6_destroy,
652 .get_mtu = esp6_get_mtu,
653 .input = esp6_input,
654 .output = esp6_output,
655 .hdr_offset = xfrm6_find_1stfragopt,
656};
657
658static struct xfrm6_protocol esp6_protocol = {
659 .handler = xfrm6_rcv,
660 .cb_handler = esp6_rcv_cb,
661 .err_handler = esp6_err,
662 .priority = 0,
663};
664
665static int __init esp6_init(void)
666{
667 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
668 pr_info("%s: can't add xfrm type\n", __func__);
669 return -EAGAIN;
670 }
671 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) {
672 pr_info("%s: can't add protocol\n", __func__);
673 xfrm_unregister_type(&esp6_type, AF_INET6);
674 return -EAGAIN;
675 }
676
677 return 0;
678}
679
680static void __exit esp6_fini(void)
681{
682 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0)
683 pr_info("%s: can't remove protocol\n", __func__);
684 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
685 pr_info("%s: can't remove xfrm type\n", __func__);
686}
687
688module_init(esp6_init);
689module_exit(esp6_fini);
690
691MODULE_LICENSE("GPL");
692MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
693
