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 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
261
262 ESP_SKB_CB(skb)->tmp = tmp;
263 err = crypto_aead_givencrypt(req);
264 if (err == -EINPROGRESS)
265 goto error;
266
267 if (err == -EBUSY)
268 err = NET_XMIT_DROP;
269
270 kfree(tmp);
271
272error:
273 return err;
274}
275
276static int esp_input_done2(struct sk_buff *skb, int err)
277{
278 const struct iphdr *iph;
279 struct xfrm_state *x = xfrm_input_state(skb);
280 struct crypto_aead *aead = x->data;
281 int alen = crypto_aead_authsize(aead);
282 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
283 int elen = skb->len - hlen;
284 int ihl;
285 u8 nexthdr[2];
286 int padlen;
287
288 kfree(ESP_SKB_CB(skb)->tmp);
289
290 if (unlikely(err))
291 goto out;
292
293 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
294 BUG();
295
296 err = -EINVAL;
297 padlen = nexthdr[0];
298 if (padlen + 2 + alen >= elen)
299 goto out;
300
301
302
303 iph = ip_hdr(skb);
304 ihl = iph->ihl * 4;
305
306 if (x->encap) {
307 struct xfrm_encap_tmpl *encap = x->encap;
308 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
309
310
311
312
313
314
315
316 if (iph->saddr != x->props.saddr.a4 ||
317 uh->source != encap->encap_sport) {
318 xfrm_address_t ipaddr;
319
320 ipaddr.a4 = iph->saddr;
321 km_new_mapping(x, &ipaddr, uh->source);
322
323
324
325
326
327
328
329
330 }
331
332
333
334
335
336
337
338
339 if (x->props.mode == XFRM_MODE_TRANSPORT)
340 skb->ip_summed = CHECKSUM_UNNECESSARY;
341 }
342
343 pskb_trim(skb, skb->len - alen - padlen - 2);
344 __skb_pull(skb, hlen);
345 if (x->props.mode == XFRM_MODE_TUNNEL)
346 skb_reset_transport_header(skb);
347 else
348 skb_set_transport_header(skb, -ihl);
349
350 err = nexthdr[1];
351
352
353 if (err == IPPROTO_NONE)
354 err = -EINVAL;
355
356out:
357 return err;
358}
359
360static void esp_input_done(struct crypto_async_request *base, int err)
361{
362 struct sk_buff *skb = base->data;
363
364 xfrm_input_resume(skb, esp_input_done2(skb, err));
365}
366
367
368
369
370
371
372static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
373{
374 struct ip_esp_hdr *esph;
375 struct crypto_aead *aead = x->data;
376 struct aead_request *req;
377 struct sk_buff *trailer;
378 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
379 int nfrags;
380 int assoclen;
381 int sglists;
382 int seqhilen;
383 __be32 *seqhi;
384 void *tmp;
385 u8 *iv;
386 struct scatterlist *sg;
387 struct scatterlist *asg;
388 int err = -EINVAL;
389
390 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
391 goto out;
392
393 if (elen <= 0)
394 goto out;
395
396 err = skb_cow_data(skb, 0, &trailer);
397 if (err < 0)
398 goto out;
399
400 nfrags = err;
401
402 assoclen = sizeof(*esph);
403 sglists = 1;
404 seqhilen = 0;
405
406 if (x->props.flags & XFRM_STATE_ESN) {
407 sglists += 2;
408 seqhilen += sizeof(__be32);
409 assoclen += seqhilen;
410 }
411
412 err = -ENOMEM;
413 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
414 if (!tmp)
415 goto out;
416
417 ESP_SKB_CB(skb)->tmp = tmp;
418 seqhi = esp_tmp_seqhi(tmp);
419 iv = esp_tmp_iv(aead, tmp, seqhilen);
420 req = esp_tmp_req(aead, iv);
421 asg = esp_req_sg(aead, req);
422 sg = asg + sglists;
423
424 skb->ip_summed = CHECKSUM_NONE;
425
426 esph = (struct ip_esp_hdr *)skb->data;
427
428
429 iv = esph->enc_data;
430
431 sg_init_table(sg, nfrags);
432 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
433
434 if ((x->props.flags & XFRM_STATE_ESN)) {
435 sg_init_table(asg, 3);
436 sg_set_buf(asg, &esph->spi, sizeof(__be32));
437 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
438 sg_set_buf(asg + 1, seqhi, seqhilen);
439 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
440 } else
441 sg_init_one(asg, esph, sizeof(*esph));
442
443 aead_request_set_callback(req, 0, esp_input_done, skb);
444 aead_request_set_crypt(req, sg, sg, elen, iv);
445 aead_request_set_assoc(req, asg, assoclen);
446
447 err = crypto_aead_decrypt(req);
448 if (err == -EINPROGRESS)
449 goto out;
450
451 err = esp_input_done2(skb, err);
452
453out:
454 return err;
455}
456
457static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
458{
459 struct crypto_aead *aead = x->data;
460 u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
461 unsigned int net_adj;
462
463 switch (x->props.mode) {
464 case XFRM_MODE_TRANSPORT:
465 case XFRM_MODE_BEET:
466 net_adj = sizeof(struct iphdr);
467 break;
468 case XFRM_MODE_TUNNEL:
469 net_adj = 0;
470 break;
471 default:
472 BUG();
473 }
474
475 return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
476 net_adj) & ~(blksize - 1)) + net_adj - 2;
477}
478
479static int esp4_err(struct sk_buff *skb, u32 info)
480{
481 struct net *net = dev_net(skb->dev);
482 const struct iphdr *iph = (const struct iphdr *)skb->data;
483 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
484 struct xfrm_state *x;
485
486 switch (icmp_hdr(skb)->type) {
487 case ICMP_DEST_UNREACH:
488 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
489 return 0;
490 case ICMP_REDIRECT:
491 break;
492 default:
493 return 0;
494 }
495
496 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
497 esph->spi, IPPROTO_ESP, AF_INET);
498 if (!x)
499 return 0;
500
501 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
502 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ESP, 0);
503 else
504 ipv4_redirect(skb, net, 0, 0, IPPROTO_ESP, 0);
505 xfrm_state_put(x);
506
507 return 0;
508}
509
510static void esp_destroy(struct xfrm_state *x)
511{
512 struct crypto_aead *aead = x->data;
513
514 if (!aead)
515 return;
516
517 crypto_free_aead(aead);
518}
519
520static int esp_init_aead(struct xfrm_state *x)
521{
522 struct crypto_aead *aead;
523 int err;
524
525 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
526 err = PTR_ERR(aead);
527 if (IS_ERR(aead))
528 goto error;
529
530 x->data = aead;
531
532 err = crypto_aead_setkey(aead, x->aead->alg_key,
533 (x->aead->alg_key_len + 7) / 8);
534 if (err)
535 goto error;
536
537 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
538 if (err)
539 goto error;
540
541error:
542 return err;
543}
544
545static int esp_init_authenc(struct xfrm_state *x)
546{
547 struct crypto_aead *aead;
548 struct crypto_authenc_key_param *param;
549 struct rtattr *rta;
550 char *key;
551 char *p;
552 char authenc_name[CRYPTO_MAX_ALG_NAME];
553 unsigned int keylen;
554 int err;
555
556 err = -EINVAL;
557 if (!x->ealg)
558 goto error;
559
560 err = -ENAMETOOLONG;
561
562 if ((x->props.flags & XFRM_STATE_ESN)) {
563 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
564 "authencesn(%s,%s)",
565 x->aalg ? x->aalg->alg_name : "digest_null",
566 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
567 goto error;
568 } else {
569 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
570 "authenc(%s,%s)",
571 x->aalg ? x->aalg->alg_name : "digest_null",
572 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
573 goto error;
574 }
575
576 aead = crypto_alloc_aead(authenc_name, 0, 0);
577 err = PTR_ERR(aead);
578 if (IS_ERR(aead))
579 goto error;
580
581 x->data = aead;
582
583 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
584 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
585 err = -ENOMEM;
586 key = kmalloc(keylen, GFP_KERNEL);
587 if (!key)
588 goto error;
589
590 p = key;
591 rta = (void *)p;
592 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
593 rta->rta_len = RTA_LENGTH(sizeof(*param));
594 param = RTA_DATA(rta);
595 p += RTA_SPACE(sizeof(*param));
596
597 if (x->aalg) {
598 struct xfrm_algo_desc *aalg_desc;
599
600 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
601 p += (x->aalg->alg_key_len + 7) / 8;
602
603 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
604 BUG_ON(!aalg_desc);
605
606 err = -EINVAL;
607 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
608 crypto_aead_authsize(aead)) {
609 pr_info("ESP: %s digestsize %u != %hu\n",
610 x->aalg->alg_name,
611 crypto_aead_authsize(aead),
612 aalg_desc->uinfo.auth.icv_fullbits / 8);
613 goto free_key;
614 }
615
616 err = crypto_aead_setauthsize(
617 aead, x->aalg->alg_trunc_len / 8);
618 if (err)
619 goto free_key;
620 }
621
622 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
623 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
624
625 err = crypto_aead_setkey(aead, key, keylen);
626
627free_key:
628 kfree(key);
629
630error:
631 return err;
632}
633
634static int esp_init_state(struct xfrm_state *x)
635{
636 struct crypto_aead *aead;
637 u32 align;
638 int err;
639
640 x->data = NULL;
641
642 if (x->aead)
643 err = esp_init_aead(x);
644 else
645 err = esp_init_authenc(x);
646
647 if (err)
648 goto error;
649
650 aead = x->data;
651
652 x->props.header_len = sizeof(struct ip_esp_hdr) +
653 crypto_aead_ivsize(aead);
654 if (x->props.mode == XFRM_MODE_TUNNEL)
655 x->props.header_len += sizeof(struct iphdr);
656 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
657 x->props.header_len += IPV4_BEET_PHMAXLEN;
658 if (x->encap) {
659 struct xfrm_encap_tmpl *encap = x->encap;
660
661 switch (encap->encap_type) {
662 default:
663 goto error;
664 case UDP_ENCAP_ESPINUDP:
665 x->props.header_len += sizeof(struct udphdr);
666 break;
667 case UDP_ENCAP_ESPINUDP_NON_IKE:
668 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
669 break;
670 }
671 }
672
673 align = ALIGN(crypto_aead_blocksize(aead), 4);
674 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
675
676error:
677 return err;
678}
679
680static int esp4_rcv_cb(struct sk_buff *skb, int err)
681{
682 return 0;
683}
684
685static const struct xfrm_type esp_type =
686{
687 .description = "ESP4",
688 .owner = THIS_MODULE,
689 .proto = IPPROTO_ESP,
690 .flags = XFRM_TYPE_REPLAY_PROT,
691 .init_state = esp_init_state,
692 .destructor = esp_destroy,
693 .get_mtu = esp4_get_mtu,
694 .input = esp_input,
695 .output = esp_output
696};
697
698static struct xfrm4_protocol esp4_protocol = {
699 .handler = xfrm4_rcv,
700 .input_handler = xfrm_input,
701 .cb_handler = esp4_rcv_cb,
702 .err_handler = esp4_err,
703 .priority = 0,
704};
705
706static int __init esp4_init(void)
707{
708 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
709 pr_info("%s: can't add xfrm type\n", __func__);
710 return -EAGAIN;
711 }
712 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
713 pr_info("%s: can't add protocol\n", __func__);
714 xfrm_unregister_type(&esp_type, AF_INET);
715 return -EAGAIN;
716 }
717 return 0;
718}
719
720static void __exit esp4_fini(void)
721{
722 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
723 pr_info("%s: can't remove protocol\n", __func__);
724 if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
725 pr_info("%s: can't remove xfrm type\n", __func__);
726}
727
728module_init(esp4_init);
729module_exit(esp4_fini);
730MODULE_LICENSE("GPL");
731MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
732
