1#define pr_fmt(fmt) "IPsec: " fmt
2
3#include <crypto/aead.h>
4#include <crypto/authenc.h>
5#include <linux/err.h>
6#include <linux/module.h>
7#include <net/ip.h>
8#include <net/xfrm.h>
9#include <net/esp.h>
10#include <linux/scatterlist.h>
11#include <linux/kernel.h>
12#include <linux/pfkeyv2.h>
13#include <linux/rtnetlink.h>
14#include <linux/slab.h>
15#include <linux/spinlock.h>
16#include <linux/in6.h>
17#include <net/icmp.h>
18#include <net/protocol.h>
19#include <net/udp.h>
20
21struct esp_skb_cb {
22 struct xfrm_skb_cb xfrm;
23 void *tmp;
24};
25
26#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
27
28static u32 esp4_get_mtu(struct xfrm_state *x, int mtu);
29
30
31
32
33
34
35
36
37
38static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqhilen)
39{
40 unsigned int len;
41
42 len = seqhilen;
43
44 len += crypto_aead_ivsize(aead);
45
46 if (len) {
47 len += crypto_aead_alignmask(aead) &
48 ~(crypto_tfm_ctx_alignment() - 1);
49 len = ALIGN(len, crypto_tfm_ctx_alignment());
50 }
51
52 len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
53 len = ALIGN(len, __alignof__(struct scatterlist));
54
55 len += sizeof(struct scatterlist) * nfrags;
56
57 return kmalloc(len, GFP_ATOMIC);
58}
59
60static inline __be32 *esp_tmp_seqhi(void *tmp)
61{
62 return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
63}
64static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
65{
66 return crypto_aead_ivsize(aead) ?
67 PTR_ALIGN((u8 *)tmp + seqhilen,
68 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
69}
70
71static inline struct aead_givcrypt_request *esp_tmp_givreq(
72 struct crypto_aead *aead, u8 *iv)
73{
74 struct aead_givcrypt_request *req;
75
76 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
77 crypto_tfm_ctx_alignment());
78 aead_givcrypt_set_tfm(req, aead);
79 return req;
80}
81
82static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
83{
84 struct aead_request *req;
85
86 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
87 crypto_tfm_ctx_alignment());
88 aead_request_set_tfm(req, aead);
89 return req;
90}
91
92static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
93 struct aead_request *req)
94{
95 return (void *)ALIGN((unsigned long)(req + 1) +
96 crypto_aead_reqsize(aead),
97 __alignof__(struct scatterlist));
98}
99
100static inline struct scatterlist *esp_givreq_sg(
101 struct crypto_aead *aead, struct aead_givcrypt_request *req)
102{
103 return (void *)ALIGN((unsigned long)(req + 1) +
104 crypto_aead_reqsize(aead),
105 __alignof__(struct scatterlist));
106}
107
108static void esp_output_done(struct crypto_async_request *base, int err)
109{
110 struct sk_buff *skb = base->data;
111
112 kfree(ESP_SKB_CB(skb)->tmp);
113 xfrm_output_resume(skb, err);
114}
115
116static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
117{
118 int err;
119 struct ip_esp_hdr *esph;
120 struct crypto_aead *aead;
121 struct aead_givcrypt_request *req;
122 struct scatterlist *sg;
123 struct scatterlist *asg;
124 struct sk_buff *trailer;
125 void *tmp;
126 u8 *iv;
127 u8 *tail;
128 int blksize;
129 int clen;
130 int alen;
131 int plen;
132 int tfclen;
133 int nfrags;
134 int assoclen;
135 int sglists;
136 int seqhilen;
137 __be32 *seqhi;
138
139
140
141 aead = x->data;
142 alen = crypto_aead_authsize(aead);
143
144 tfclen = 0;
145 if (x->tfcpad) {
146 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
147 u32 padto;
148
149 padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached));
150 if (skb->len < padto)
151 tfclen = padto - skb->len;
152 }
153 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
154 clen = ALIGN(skb->len + 2 + tfclen, blksize);
155 plen = clen - skb->len - tfclen;
156
157 err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
158 if (err < 0)
159 goto error;
160 nfrags = err;
161
162 assoclen = sizeof(*esph);
163 sglists = 1;
164 seqhilen = 0;
165
166 if (x->props.flags & XFRM_STATE_ESN) {
167 sglists += 2;
168 seqhilen += sizeof(__be32);
169 assoclen += seqhilen;
170 }
171
172 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
173 if (!tmp) {
174 err = -ENOMEM;
175 goto error;
176 }
177
178 seqhi = esp_tmp_seqhi(tmp);
179 iv = esp_tmp_iv(aead, tmp, seqhilen);
180 req = esp_tmp_givreq(aead, iv);
181 asg = esp_givreq_sg(aead, req);
182 sg = asg + sglists;
183
184
185 tail = skb_tail_pointer(trailer);
186 if (tfclen) {
187 memset(tail, 0, tfclen);
188 tail += tfclen;
189 }
190 do {
191 int i;
192 for (i = 0; i < plen - 2; i++)
193 tail[i] = i + 1;
194 } while (0);
195 tail[plen - 2] = plen - 2;
196 tail[plen - 1] = *skb_mac_header(skb);
197 pskb_put(skb, trailer, clen - skb->len + alen);
198
199 skb_push(skb, -skb_network_offset(skb));
200 esph = ip_esp_hdr(skb);
201 *skb_mac_header(skb) = IPPROTO_ESP;
202
203
204 if (x->encap) {
205 struct xfrm_encap_tmpl *encap = x->encap;
206 struct udphdr *uh;
207 __be32 *udpdata32;
208 __be16 sport, dport;
209 int encap_type;
210
211 spin_lock_bh(&x->lock);
212 sport = encap->encap_sport;
213 dport = encap->encap_dport;
214 encap_type = encap->encap_type;
215 spin_unlock_bh(&x->lock);
216
217 uh = (struct udphdr *)esph;
218 uh->source = sport;
219 uh->dest = dport;
220 uh->len = htons(skb->len - skb_transport_offset(skb));
221 uh->check = 0;
222
223 switch (encap_type) {
224 default:
225 case UDP_ENCAP_ESPINUDP:
226 esph = (struct ip_esp_hdr *)(uh + 1);
227 break;
228 case UDP_ENCAP_ESPINUDP_NON_IKE:
229 udpdata32 = (__be32 *)(uh + 1);
230 udpdata32[0] = udpdata32[1] = 0;
231 esph = (struct ip_esp_hdr *)(udpdata32 + 2);
232 break;
233 }
234
235 *skb_mac_header(skb) = IPPROTO_UDP;
236 }
237
238 esph->spi = x->id.spi;
239 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
240
241 sg_init_table(sg, nfrags);
242 skb_to_sgvec(skb, sg,
243 esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
244 clen + alen);
245
246 if ((x->props.flags & XFRM_STATE_ESN)) {
247 sg_init_table(asg, 3);
248 sg_set_buf(asg, &esph->spi, sizeof(__be32));
249 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
250 sg_set_buf(asg + 1, seqhi, seqhilen);
251 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
252 } else
253 sg_init_one(asg, esph, sizeof(*esph));
254
255 aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
256 aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
257 aead_givcrypt_set_assoc(req, asg, assoclen);
258 aead_givcrypt_set_giv(req, esph->enc_data,
259 XFRM_SKB_CB(skb)->seq.output.low);
260
261 ESP_SKB_CB(skb)->tmp = tmp;
262 err = crypto_aead_givencrypt(req);
263 if (err == -EINPROGRESS)
264 goto error;
265
266 if (err == -EBUSY)
267 err = NET_XMIT_DROP;
268
269 kfree(tmp);
270
271error:
272 return err;
273}
274
275static int esp_input_done2(struct sk_buff *skb, int err)
276{
277 const struct iphdr *iph;
278 struct xfrm_state *x = xfrm_input_state(skb);
279 struct crypto_aead *aead = x->data;
280 int alen = crypto_aead_authsize(aead);
281 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
282 int elen = skb->len - hlen;
283 int ihl;
284 u8 nexthdr[2];
285 int padlen;
286
287 kfree(ESP_SKB_CB(skb)->tmp);
288
289 if (unlikely(err))
290 goto out;
291
292 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
293 BUG();
294
295 err = -EINVAL;
296 padlen = nexthdr[0];
297 if (padlen + 2 + alen >= elen)
298 goto out;
299
300
301
302 iph = ip_hdr(skb);
303 ihl = iph->ihl * 4;
304
305 if (x->encap) {
306 struct xfrm_encap_tmpl *encap = x->encap;
307 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
308
309
310
311
312
313
314
315 if (iph->saddr != x->props.saddr.a4 ||
316 uh->source != encap->encap_sport) {
317 xfrm_address_t ipaddr;
318
319 ipaddr.a4 = iph->saddr;
320 km_new_mapping(x, &ipaddr, uh->source);
321
322
323
324
325
326
327
328
329 }
330
331
332
333
334
335
336
337
338 if (x->props.mode == XFRM_MODE_TRANSPORT)
339 skb->ip_summed = CHECKSUM_UNNECESSARY;
340 }
341
342 pskb_trim(skb, skb->len - alen - padlen - 2);
343 __skb_pull(skb, hlen);
344 if (x->props.mode == XFRM_MODE_TUNNEL)
345 skb_reset_transport_header(skb);
346 else
347 skb_set_transport_header(skb, -ihl);
348
349 err = nexthdr[1];
350
351
352 if (err == IPPROTO_NONE)
353 err = -EINVAL;
354
355out:
356 return err;
357}
358
359static void esp_input_done(struct crypto_async_request *base, int err)
360{
361 struct sk_buff *skb = base->data;
362
363 xfrm_input_resume(skb, esp_input_done2(skb, err));
364}
365
366
367
368
369
370
371static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
372{
373 struct ip_esp_hdr *esph;
374 struct crypto_aead *aead = x->data;
375 struct aead_request *req;
376 struct sk_buff *trailer;
377 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
378 int nfrags;
379 int assoclen;
380 int sglists;
381 int seqhilen;
382 __be32 *seqhi;
383 void *tmp;
384 u8 *iv;
385 struct scatterlist *sg;
386 struct scatterlist *asg;
387 int err = -EINVAL;
388
389 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
390 goto out;
391
392 if (elen <= 0)
393 goto out;
394
395 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
396 goto out;
397 nfrags = err;
398
399 assoclen = sizeof(*esph);
400 sglists = 1;
401 seqhilen = 0;
402
403 if (x->props.flags & XFRM_STATE_ESN) {
404 sglists += 2;
405 seqhilen += sizeof(__be32);
406 assoclen += seqhilen;
407 }
408
409 err = -ENOMEM;
410 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
411 if (!tmp)
412 goto out;
413
414 ESP_SKB_CB(skb)->tmp = tmp;
415 seqhi = esp_tmp_seqhi(tmp);
416 iv = esp_tmp_iv(aead, tmp, seqhilen);
417 req = esp_tmp_req(aead, iv);
418 asg = esp_req_sg(aead, req);
419 sg = asg + sglists;
420
421 skb->ip_summed = CHECKSUM_NONE;
422
423 esph = (struct ip_esp_hdr *)skb->data;
424
425
426 iv = esph->enc_data;
427
428 sg_init_table(sg, nfrags);
429 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
430
431 if ((x->props.flags & XFRM_STATE_ESN)) {
432 sg_init_table(asg, 3);
433 sg_set_buf(asg, &esph->spi, sizeof(__be32));
434 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
435 sg_set_buf(asg + 1, seqhi, seqhilen);
436 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
437 } else
438 sg_init_one(asg, esph, sizeof(*esph));
439
440 aead_request_set_callback(req, 0, esp_input_done, skb);
441 aead_request_set_crypt(req, sg, sg, elen, iv);
442 aead_request_set_assoc(req, asg, assoclen);
443
444 err = crypto_aead_decrypt(req);
445 if (err == -EINPROGRESS)
446 goto out;
447
448 err = esp_input_done2(skb, err);
449
450out:
451 return err;
452}
453
454static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
455{
456 struct crypto_aead *aead = x->data;
457 u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
458 unsigned int net_adj;
459
460 switch (x->props.mode) {
461 case XFRM_MODE_TRANSPORT:
462 case XFRM_MODE_BEET:
463 net_adj = sizeof(struct iphdr);
464 break;
465 case XFRM_MODE_TUNNEL:
466 net_adj = 0;
467 break;
468 default:
469 BUG();
470 }
471
472 return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
473 net_adj) & ~(blksize - 1)) + net_adj - 2;
474}
475
476static void esp4_err(struct sk_buff *skb, u32 info)
477{
478 struct net *net = dev_net(skb->dev);
479 const struct iphdr *iph = (const struct iphdr *)skb->data;
480 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
481 struct xfrm_state *x;
482
483 switch (icmp_hdr(skb)->type) {
484 case ICMP_DEST_UNREACH:
485 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
486 return;
487 case ICMP_REDIRECT:
488 break;
489 default:
490 return;
491 }
492
493 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
494 esph->spi, IPPROTO_ESP, AF_INET);
495 if (!x)
496 return;
497
498 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
499 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ESP, 0);
500 else
501 ipv4_redirect(skb, net, 0, 0, IPPROTO_ESP, 0);
502 xfrm_state_put(x);
503}
504
505static void esp_destroy(struct xfrm_state *x)
506{
507 struct crypto_aead *aead = x->data;
508
509 if (!aead)
510 return;
511
512 crypto_free_aead(aead);
513}
514
515static int esp_init_aead(struct xfrm_state *x)
516{
517 struct crypto_aead *aead;
518 int err;
519
520 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
521 err = PTR_ERR(aead);
522 if (IS_ERR(aead))
523 goto error;
524
525 x->data = aead;
526
527 err = crypto_aead_setkey(aead, x->aead->alg_key,
528 (x->aead->alg_key_len + 7) / 8);
529 if (err)
530 goto error;
531
532 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
533 if (err)
534 goto error;
535
536error:
537 return err;
538}
539
540static int esp_init_authenc(struct xfrm_state *x)
541{
542 struct crypto_aead *aead;
543 struct crypto_authenc_key_param *param;
544 struct rtattr *rta;
545 char *key;
546 char *p;
547 char authenc_name[CRYPTO_MAX_ALG_NAME];
548 unsigned int keylen;
549 int err;
550
551 err = -EINVAL;
552 if (x->ealg == NULL)
553 goto error;
554
555 err = -ENAMETOOLONG;
556
557 if ((x->props.flags & XFRM_STATE_ESN)) {
558 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
559 "authencesn(%s,%s)",
560 x->aalg ? x->aalg->alg_name : "digest_null",
561 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
562 goto error;
563 } else {
564 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
565 "authenc(%s,%s)",
566 x->aalg ? x->aalg->alg_name : "digest_null",
567 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
568 goto error;
569 }
570
571 aead = crypto_alloc_aead(authenc_name, 0, 0);
572 err = PTR_ERR(aead);
573 if (IS_ERR(aead))
574 goto error;
575
576 x->data = aead;
577
578 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
579 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
580 err = -ENOMEM;
581 key = kmalloc(keylen, GFP_KERNEL);
582 if (!key)
583 goto error;
584
585 p = key;
586 rta = (void *)p;
587 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
588 rta->rta_len = RTA_LENGTH(sizeof(*param));
589 param = RTA_DATA(rta);
590 p += RTA_SPACE(sizeof(*param));
591
592 if (x->aalg) {
593 struct xfrm_algo_desc *aalg_desc;
594
595 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
596 p += (x->aalg->alg_key_len + 7) / 8;
597
598 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
599 BUG_ON(!aalg_desc);
600
601 err = -EINVAL;
602 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
603 crypto_aead_authsize(aead)) {
604 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
605 x->aalg->alg_name,
606 crypto_aead_authsize(aead),
607 aalg_desc->uinfo.auth.icv_fullbits/8);
608 goto free_key;
609 }
610
611 err = crypto_aead_setauthsize(
612 aead, x->aalg->alg_trunc_len / 8);
613 if (err)
614 goto free_key;
615 }
616
617 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
618 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
619
620 err = crypto_aead_setkey(aead, key, keylen);
621
622free_key:
623 kfree(key);
624
625error:
626 return err;
627}
628
629static int esp_init_state(struct xfrm_state *x)
630{
631 struct crypto_aead *aead;
632 u32 align;
633 int err;
634
635 x->data = NULL;
636
637 if (x->aead)
638 err = esp_init_aead(x);
639 else
640 err = esp_init_authenc(x);
641
642 if (err)
643 goto error;
644
645 aead = x->data;
646
647 x->props.header_len = sizeof(struct ip_esp_hdr) +
648 crypto_aead_ivsize(aead);
649 if (x->props.mode == XFRM_MODE_TUNNEL)
650 x->props.header_len += sizeof(struct iphdr);
651 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
652 x->props.header_len += IPV4_BEET_PHMAXLEN;
653 if (x->encap) {
654 struct xfrm_encap_tmpl *encap = x->encap;
655
656 switch (encap->encap_type) {
657 default:
658 goto error;
659 case UDP_ENCAP_ESPINUDP:
660 x->props.header_len += sizeof(struct udphdr);
661 break;
662 case UDP_ENCAP_ESPINUDP_NON_IKE:
663 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
664 break;
665 }
666 }
667
668 align = ALIGN(crypto_aead_blocksize(aead), 4);
669 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
670
671error:
672 return err;
673}
674
675static const struct xfrm_type esp_type =
676{
677 .description = "ESP4",
678 .owner = THIS_MODULE,
679 .proto = IPPROTO_ESP,
680 .flags = XFRM_TYPE_REPLAY_PROT,
681 .init_state = esp_init_state,
682 .destructor = esp_destroy,
683 .get_mtu = esp4_get_mtu,
684 .input = esp_input,
685 .output = esp_output
686};
687
688static const struct net_protocol esp4_protocol = {
689 .handler = xfrm4_rcv,
690 .err_handler = esp4_err,
691 .no_policy = 1,
692 .netns_ok = 1,
693};
694
695static int __init esp4_init(void)
696{
697 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
698 pr_info("%s: can't add xfrm type\n", __func__);
699 return -EAGAIN;
700 }
701 if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
702 pr_info("%s: can't add protocol\n", __func__);
703 xfrm_unregister_type(&esp_type, AF_INET);
704 return -EAGAIN;
705 }
706 return 0;
707}
708
709static void __exit esp4_fini(void)
710{
711 if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
712 pr_info("%s: can't remove protocol\n", __func__);
713 if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
714 pr_info("%s: can't remove xfrm type\n", __func__);
715}
716
717module_init(esp4_init);
718module_exit(esp4_fini);
719MODULE_LICENSE("GPL");
720MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
721
