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_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_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
72{
73 struct aead_request *req;
74
75 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
76 crypto_tfm_ctx_alignment());
77 aead_request_set_tfm(req, aead);
78 return req;
79}
80
81static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
82 struct aead_request *req)
83{
84 return (void *)ALIGN((unsigned long)(req + 1) +
85 crypto_aead_reqsize(aead),
86 __alignof__(struct scatterlist));
87}
88
89static void esp_output_done(struct crypto_async_request *base, int err)
90{
91 struct sk_buff *skb = base->data;
92
93 kfree(ESP_SKB_CB(skb)->tmp);
94 xfrm_output_resume(skb, err);
95}
96
97
98static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
99{
100 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
101 void *tmp = ESP_SKB_CB(skb)->tmp;
102 __be32 *seqhi = esp_tmp_seqhi(tmp);
103
104 esph->seq_no = esph->spi;
105 esph->spi = *seqhi;
106}
107
108static void esp_output_restore_header(struct sk_buff *skb)
109{
110 esp_restore_header(skb, skb_transport_offset(skb) - sizeof(__be32));
111}
112
113static void esp_output_done_esn(struct crypto_async_request *base, int err)
114{
115 struct sk_buff *skb = base->data;
116
117 esp_output_restore_header(skb);
118 esp_output_done(base, err);
119}
120
121static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
122{
123 int err;
124 struct ip_esp_hdr *esph;
125 struct crypto_aead *aead;
126 struct aead_request *req;
127 struct scatterlist *sg;
128 struct sk_buff *trailer;
129 void *tmp;
130 u8 *iv;
131 u8 *tail;
132 int blksize;
133 int clen;
134 int alen;
135 int plen;
136 int ivlen;
137 int tfclen;
138 int nfrags;
139 int assoclen;
140 int seqhilen;
141 __be32 *seqhi;
142 __be64 seqno;
143
144
145
146 aead = x->data;
147 alen = crypto_aead_authsize(aead);
148 ivlen = crypto_aead_ivsize(aead);
149
150 tfclen = 0;
151 if (x->tfcpad) {
152 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
153 u32 padto;
154
155 padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached));
156 if (skb->len < padto)
157 tfclen = padto - skb->len;
158 }
159 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
160 clen = ALIGN(skb->len + 2 + tfclen, blksize);
161 plen = clen - skb->len - tfclen;
162
163 err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
164 if (err < 0)
165 goto error;
166 nfrags = err;
167
168 assoclen = sizeof(*esph);
169 seqhilen = 0;
170
171 if (x->props.flags & XFRM_STATE_ESN) {
172 seqhilen += sizeof(__be32);
173 assoclen += seqhilen;
174 }
175
176 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
177 if (!tmp) {
178 err = -ENOMEM;
179 goto error;
180 }
181
182 seqhi = esp_tmp_seqhi(tmp);
183 iv = esp_tmp_iv(aead, tmp, seqhilen);
184 req = esp_tmp_req(aead, iv);
185 sg = esp_req_sg(aead, req);
186
187
188 tail = skb_tail_pointer(trailer);
189 if (tfclen) {
190 memset(tail, 0, tfclen);
191 tail += tfclen;
192 }
193 do {
194 int i;
195 for (i = 0; i < plen - 2; i++)
196 tail[i] = i + 1;
197 } while (0);
198 tail[plen - 2] = plen - 2;
199 tail[plen - 1] = *skb_mac_header(skb);
200 pskb_put(skb, trailer, clen - skb->len + alen);
201
202 skb_push(skb, -skb_network_offset(skb));
203 esph = ip_esp_hdr(skb);
204 *skb_mac_header(skb) = IPPROTO_ESP;
205
206
207 if (x->encap) {
208 struct xfrm_encap_tmpl *encap = x->encap;
209 struct udphdr *uh;
210 __be32 *udpdata32;
211 __be16 sport, dport;
212 int encap_type;
213
214 spin_lock_bh(&x->lock);
215 sport = encap->encap_sport;
216 dport = encap->encap_dport;
217 encap_type = encap->encap_type;
218 spin_unlock_bh(&x->lock);
219
220 uh = (struct udphdr *)esph;
221 uh->source = sport;
222 uh->dest = dport;
223 uh->len = htons(skb->len - skb_transport_offset(skb));
224 uh->check = 0;
225
226 switch (encap_type) {
227 default:
228 case UDP_ENCAP_ESPINUDP:
229 esph = (struct ip_esp_hdr *)(uh + 1);
230 break;
231 case UDP_ENCAP_ESPINUDP_NON_IKE:
232 udpdata32 = (__be32 *)(uh + 1);
233 udpdata32[0] = udpdata32[1] = 0;
234 esph = (struct ip_esp_hdr *)(udpdata32 + 2);
235 break;
236 }
237
238 *skb_mac_header(skb) = IPPROTO_UDP;
239 }
240
241 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
242
243 aead_request_set_callback(req, 0, esp_output_done, skb);
244
245
246
247
248
249 if ((x->props.flags & XFRM_STATE_ESN)) {
250 esph = (void *)(skb_transport_header(skb) - sizeof(__be32));
251 *seqhi = esph->spi;
252 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
253 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
254 }
255
256 esph->spi = x->id.spi;
257
258 sg_init_table(sg, nfrags);
259 skb_to_sgvec(skb, sg,
260 (unsigned char *)esph - skb->data,
261 assoclen + ivlen + clen + alen);
262
263 aead_request_set_crypt(req, sg, sg, ivlen + clen, iv);
264 aead_request_set_ad(req, assoclen);
265
266 seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
267 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
268
269 memset(iv, 0, ivlen);
270 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&seqno + 8 - min(ivlen, 8),
271 min(ivlen, 8));
272
273 ESP_SKB_CB(skb)->tmp = tmp;
274 err = crypto_aead_encrypt(req);
275
276 switch (err) {
277 case -EINPROGRESS:
278 goto error;
279
280 case -EBUSY:
281 err = NET_XMIT_DROP;
282 break;
283
284 case 0:
285 if ((x->props.flags & XFRM_STATE_ESN))
286 esp_output_restore_header(skb);
287 }
288
289 kfree(tmp);
290
291error:
292 return err;
293}
294
295static int esp_input_done2(struct sk_buff *skb, int err)
296{
297 const struct iphdr *iph;
298 struct xfrm_state *x = xfrm_input_state(skb);
299 struct crypto_aead *aead = x->data;
300 int alen = crypto_aead_authsize(aead);
301 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
302 int elen = skb->len - hlen;
303 int ihl;
304 u8 nexthdr[2];
305 int padlen;
306
307 kfree(ESP_SKB_CB(skb)->tmp);
308
309 if (unlikely(err))
310 goto out;
311
312 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
313 BUG();
314
315 err = -EINVAL;
316 padlen = nexthdr[0];
317 if (padlen + 2 + alen >= elen)
318 goto out;
319
320
321
322 iph = ip_hdr(skb);
323 ihl = iph->ihl * 4;
324
325 if (x->encap) {
326 struct xfrm_encap_tmpl *encap = x->encap;
327 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
328
329
330
331
332
333
334
335 if (iph->saddr != x->props.saddr.a4 ||
336 uh->source != encap->encap_sport) {
337 xfrm_address_t ipaddr;
338
339 ipaddr.a4 = iph->saddr;
340 km_new_mapping(x, &ipaddr, uh->source);
341
342
343
344
345
346
347
348
349 }
350
351
352
353
354
355
356
357
358 if (x->props.mode == XFRM_MODE_TRANSPORT)
359 skb->ip_summed = CHECKSUM_UNNECESSARY;
360 }
361
362 pskb_trim(skb, skb->len - alen - padlen - 2);
363 __skb_pull(skb, hlen);
364 if (x->props.mode == XFRM_MODE_TUNNEL)
365 skb_reset_transport_header(skb);
366 else
367 skb_set_transport_header(skb, -ihl);
368
369 err = nexthdr[1];
370
371
372 if (err == IPPROTO_NONE)
373 err = -EINVAL;
374
375out:
376 return err;
377}
378
379static void esp_input_done(struct crypto_async_request *base, int err)
380{
381 struct sk_buff *skb = base->data;
382
383 xfrm_input_resume(skb, esp_input_done2(skb, err));
384}
385
386static void esp_input_restore_header(struct sk_buff *skb)
387{
388 esp_restore_header(skb, 0);
389 __skb_pull(skb, 4);
390}
391
392static void esp_input_done_esn(struct crypto_async_request *base, int err)
393{
394 struct sk_buff *skb = base->data;
395
396 esp_input_restore_header(skb);
397 esp_input_done(base, err);
398}
399
400
401
402
403
404
405static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
406{
407 struct ip_esp_hdr *esph;
408 struct crypto_aead *aead = x->data;
409 struct aead_request *req;
410 struct sk_buff *trailer;
411 int ivlen = crypto_aead_ivsize(aead);
412 int elen = skb->len - sizeof(*esph) - ivlen;
413 int nfrags;
414 int assoclen;
415 int seqhilen;
416 __be32 *seqhi;
417 void *tmp;
418 u8 *iv;
419 struct scatterlist *sg;
420 int err = -EINVAL;
421
422 if (!pskb_may_pull(skb, sizeof(*esph) + ivlen))
423 goto out;
424
425 if (elen <= 0)
426 goto out;
427
428 err = skb_cow_data(skb, 0, &trailer);
429 if (err < 0)
430 goto out;
431
432 nfrags = err;
433
434 assoclen = sizeof(*esph);
435 seqhilen = 0;
436
437 if (x->props.flags & XFRM_STATE_ESN) {
438 seqhilen += sizeof(__be32);
439 assoclen += seqhilen;
440 }
441
442 err = -ENOMEM;
443 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
444 if (!tmp)
445 goto out;
446
447 ESP_SKB_CB(skb)->tmp = tmp;
448 seqhi = esp_tmp_seqhi(tmp);
449 iv = esp_tmp_iv(aead, tmp, seqhilen);
450 req = esp_tmp_req(aead, iv);
451 sg = esp_req_sg(aead, req);
452
453 skb->ip_summed = CHECKSUM_NONE;
454
455 esph = (struct ip_esp_hdr *)skb->data;
456
457 aead_request_set_callback(req, 0, esp_input_done, skb);
458
459
460
461
462
463 if ((x->props.flags & XFRM_STATE_ESN)) {
464 esph = (void *)skb_push(skb, 4);
465 *seqhi = esph->spi;
466 esph->spi = esph->seq_no;
467 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.input.hi);
468 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
469 }
470
471 sg_init_table(sg, nfrags);
472 skb_to_sgvec(skb, sg, 0, skb->len);
473
474 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
475 aead_request_set_ad(req, assoclen);
476
477 err = crypto_aead_decrypt(req);
478 if (err == -EINPROGRESS)
479 goto out;
480
481 if ((x->props.flags & XFRM_STATE_ESN))
482 esp_input_restore_header(skb);
483
484 err = esp_input_done2(skb, err);
485
486out:
487 return err;
488}
489
490static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
491{
492 struct crypto_aead *aead = x->data;
493 u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
494 unsigned int net_adj;
495
496 switch (x->props.mode) {
497 case XFRM_MODE_TRANSPORT:
498 case XFRM_MODE_BEET:
499 net_adj = sizeof(struct iphdr);
500 break;
501 case XFRM_MODE_TUNNEL:
502 net_adj = 0;
503 break;
504 default:
505 BUG();
506 }
507
508 return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
509 net_adj) & ~(blksize - 1)) + net_adj - 2;
510}
511
512static int esp4_err(struct sk_buff *skb, u32 info)
513{
514 struct net *net = dev_net(skb->dev);
515 const struct iphdr *iph = (const struct iphdr *)skb->data;
516 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
517 struct xfrm_state *x;
518
519 switch (icmp_hdr(skb)->type) {
520 case ICMP_DEST_UNREACH:
521 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
522 return 0;
523 case ICMP_REDIRECT:
524 break;
525 default:
526 return 0;
527 }
528
529 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
530 esph->spi, IPPROTO_ESP, AF_INET);
531 if (!x)
532 return 0;
533
534 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
535 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ESP, 0);
536 else
537 ipv4_redirect(skb, net, 0, 0, IPPROTO_ESP, 0);
538 xfrm_state_put(x);
539
540 return 0;
541}
542
543static void esp_destroy(struct xfrm_state *x)
544{
545 struct crypto_aead *aead = x->data;
546
547 if (!aead)
548 return;
549
550 crypto_free_aead(aead);
551}
552
553static int esp_init_aead(struct xfrm_state *x)
554{
555 char aead_name[CRYPTO_MAX_ALG_NAME];
556 struct crypto_aead *aead;
557 int err;
558
559 err = -ENAMETOOLONG;
560 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
561 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
562 goto error;
563
564 aead = crypto_alloc_aead(aead_name, 0, 0);
565 err = PTR_ERR(aead);
566 if (IS_ERR(aead))
567 goto error;
568
569 x->data = aead;
570
571 err = crypto_aead_setkey(aead, x->aead->alg_key,
572 (x->aead->alg_key_len + 7) / 8);
573 if (err)
574 goto error;
575
576 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
577 if (err)
578 goto error;
579
580error:
581 return err;
582}
583
584static int esp_init_authenc(struct xfrm_state *x)
585{
586 struct crypto_aead *aead;
587 struct crypto_authenc_key_param *param;
588 struct rtattr *rta;
589 char *key;
590 char *p;
591 char authenc_name[CRYPTO_MAX_ALG_NAME];
592 unsigned int keylen;
593 int err;
594
595 err = -EINVAL;
596 if (!x->ealg)
597 goto error;
598
599 err = -ENAMETOOLONG;
600
601 if ((x->props.flags & XFRM_STATE_ESN)) {
602 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
603 "%s%sauthencesn(%s,%s)%s",
604 x->geniv ?: "", x->geniv ? "(" : "",
605 x->aalg ? x->aalg->alg_name : "digest_null",
606 x->ealg->alg_name,
607 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
608 goto error;
609 } else {
610 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
611 "%s%sauthenc(%s,%s)%s",
612 x->geniv ?: "", x->geniv ? "(" : "",
613 x->aalg ? x->aalg->alg_name : "digest_null",
614 x->ealg->alg_name,
615 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
616 goto error;
617 }
618
619 aead = crypto_alloc_aead(authenc_name, 0, 0);
620 err = PTR_ERR(aead);
621 if (IS_ERR(aead))
622 goto error;
623
624 x->data = aead;
625
626 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
627 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
628 err = -ENOMEM;
629 key = kmalloc(keylen, GFP_KERNEL);
630 if (!key)
631 goto error;
632
633 p = key;
634 rta = (void *)p;
635 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
636 rta->rta_len = RTA_LENGTH(sizeof(*param));
637 param = RTA_DATA(rta);
638 p += RTA_SPACE(sizeof(*param));
639
640 if (x->aalg) {
641 struct xfrm_algo_desc *aalg_desc;
642
643 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
644 p += (x->aalg->alg_key_len + 7) / 8;
645
646 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
647 BUG_ON(!aalg_desc);
648
649 err = -EINVAL;
650 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
651 crypto_aead_authsize(aead)) {
652 pr_info("ESP: %s digestsize %u != %hu\n",
653 x->aalg->alg_name,
654 crypto_aead_authsize(aead),
655 aalg_desc->uinfo.auth.icv_fullbits / 8);
656 goto free_key;
657 }
658
659 err = crypto_aead_setauthsize(
660 aead, x->aalg->alg_trunc_len / 8);
661 if (err)
662 goto free_key;
663 }
664
665 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
666 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
667
668 err = crypto_aead_setkey(aead, key, keylen);
669
670free_key:
671 kfree(key);
672
673error:
674 return err;
675}
676
677static int esp_init_state(struct xfrm_state *x)
678{
679 struct crypto_aead *aead;
680 u32 align;
681 int err;
682
683 x->data = NULL;
684
685 if (x->aead)
686 err = esp_init_aead(x);
687 else
688 err = esp_init_authenc(x);
689
690 if (err)
691 goto error;
692
693 aead = x->data;
694
695 x->props.header_len = sizeof(struct ip_esp_hdr) +
696 crypto_aead_ivsize(aead);
697 if (x->props.mode == XFRM_MODE_TUNNEL)
698 x->props.header_len += sizeof(struct iphdr);
699 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
700 x->props.header_len += IPV4_BEET_PHMAXLEN;
701 if (x->encap) {
702 struct xfrm_encap_tmpl *encap = x->encap;
703
704 switch (encap->encap_type) {
705 default:
706 goto error;
707 case UDP_ENCAP_ESPINUDP:
708 x->props.header_len += sizeof(struct udphdr);
709 break;
710 case UDP_ENCAP_ESPINUDP_NON_IKE:
711 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
712 break;
713 }
714 }
715
716 align = ALIGN(crypto_aead_blocksize(aead), 4);
717 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
718
719error:
720 return err;
721}
722
723static int esp4_rcv_cb(struct sk_buff *skb, int err)
724{
725 return 0;
726}
727
728static const struct xfrm_type esp_type =
729{
730 .description = "ESP4",
731 .owner = THIS_MODULE,
732 .proto = IPPROTO_ESP,
733 .flags = XFRM_TYPE_REPLAY_PROT,
734 .init_state = esp_init_state,
735 .destructor = esp_destroy,
736 .get_mtu = esp4_get_mtu,
737 .input = esp_input,
738 .output = esp_output
739};
740
741static struct xfrm4_protocol esp4_protocol = {
742 .handler = xfrm4_rcv,
743 .input_handler = xfrm_input,
744 .cb_handler = esp4_rcv_cb,
745 .err_handler = esp4_err,
746 .priority = 0,
747};
748
749static int __init esp4_init(void)
750{
751 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
752 pr_info("%s: can't add xfrm type\n", __func__);
753 return -EAGAIN;
754 }
755 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
756 pr_info("%s: can't add protocol\n", __func__);
757 xfrm_unregister_type(&esp_type, AF_INET);
758 return -EAGAIN;
759 }
760 return 0;
761}
762
763static void __exit esp4_fini(void)
764{
765 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
766 pr_info("%s: can't remove protocol\n", __func__);
767 if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
768 pr_info("%s: can't remove xfrm type\n", __func__);
769}
770
771module_init(esp4_init);
772module_exit(esp4_fini);
773MODULE_LICENSE("GPL");
774MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
775
