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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 * Allocate an AEAD request structure with extra space for SG and IV.
32 *
33 * For alignment considerations the IV is placed at the front, followed
34 * by the request and finally the SG list.
35 *
36 * TODO: Use spare space in skb for this where possible.
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/* Move ESP header back into place. */
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 /* skb is pure payload to encrypt */
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 /* Fill padding... */
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 /* this is non-NULL only with UDP Encapsulation */
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 /* For ESN we move the header forward by 4 bytes to
246 * accomodate the high bits. We will move it back after
247 * encryption.
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 /* ... check padding bits here. Silly. :-) */
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 * 1) if the NAT-T peer's IP or port changed then
331 * advertize the change to the keying daemon.
332 * This is an inbound SA, so just compare
333 * SRC ports.
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 /* XXX: perhaps add an extra
343 * policy check here, to see
344 * if we should allow or
345 * reject a packet from a
346 * different source
347 * address/port.
348 */
349 }
350
351 /*
352 * 2) ignore UDP/TCP checksums in case
353 * of NAT-T in Transport Mode, or
354 * perform other post-processing fixes
355 * as per draft-ietf-ipsec-udp-encaps-06,
356 * section 3.1.2
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 /* RFC4303: Drop dummy packets without any error */
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 * Note: detecting truncated vs. non-truncated authentication data is very
402 * expensive, so we only support truncated data, which is the recommended
403 * and common case.
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 /* For ESN we move the header forward by 4 bytes to
460 * accomodate the high bits. We will move it back after
461 * decryption.
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);
1// SPDX-License-Identifier: GPL-2.0-only
2#define pr_fmt(fmt) "IPsec: " fmt
3
4#include <crypto/aead.h>
5#include <crypto/authenc.h>
6#include <linux/err.h>
7#include <linux/module.h>
8#include <net/ip.h>
9#include <net/xfrm.h>
10#include <net/esp.h>
11#include <linux/scatterlist.h>
12#include <linux/kernel.h>
13#include <linux/pfkeyv2.h>
14#include <linux/rtnetlink.h>
15#include <linux/slab.h>
16#include <linux/spinlock.h>
17#include <linux/in6.h>
18#include <net/icmp.h>
19#include <net/protocol.h>
20#include <net/udp.h>
21
22#include <linux/highmem.h>
23
24struct esp_skb_cb {
25 struct xfrm_skb_cb xfrm;
26 void *tmp;
27};
28
29struct esp_output_extra {
30 __be32 seqhi;
31 u32 esphoff;
32};
33
34#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
35
36/*
37 * Allocate an AEAD request structure with extra space for SG and IV.
38 *
39 * For alignment considerations the IV is placed at the front, followed
40 * by the request and finally the SG list.
41 *
42 * TODO: Use spare space in skb for this where possible.
43 */
44static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen)
45{
46 unsigned int len;
47
48 len = extralen;
49
50 len += crypto_aead_ivsize(aead);
51
52 if (len) {
53 len += crypto_aead_alignmask(aead) &
54 ~(crypto_tfm_ctx_alignment() - 1);
55 len = ALIGN(len, crypto_tfm_ctx_alignment());
56 }
57
58 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
59 len = ALIGN(len, __alignof__(struct scatterlist));
60
61 len += sizeof(struct scatterlist) * nfrags;
62
63 return kmalloc(len, GFP_ATOMIC);
64}
65
66static inline void *esp_tmp_extra(void *tmp)
67{
68 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
69}
70
71static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen)
72{
73 return crypto_aead_ivsize(aead) ?
74 PTR_ALIGN((u8 *)tmp + extralen,
75 crypto_aead_alignmask(aead) + 1) : tmp + extralen;
76}
77
78static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
79{
80 struct aead_request *req;
81
82 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
83 crypto_tfm_ctx_alignment());
84 aead_request_set_tfm(req, aead);
85 return req;
86}
87
88static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
89 struct aead_request *req)
90{
91 return (void *)ALIGN((unsigned long)(req + 1) +
92 crypto_aead_reqsize(aead),
93 __alignof__(struct scatterlist));
94}
95
96static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
97{
98 struct esp_output_extra *extra = esp_tmp_extra(tmp);
99 struct crypto_aead *aead = x->data;
100 int extralen = 0;
101 u8 *iv;
102 struct aead_request *req;
103 struct scatterlist *sg;
104
105 if (x->props.flags & XFRM_STATE_ESN)
106 extralen += sizeof(*extra);
107
108 extra = esp_tmp_extra(tmp);
109 iv = esp_tmp_iv(aead, tmp, extralen);
110 req = esp_tmp_req(aead, iv);
111
112 /* Unref skb_frag_pages in the src scatterlist if necessary.
113 * Skip the first sg which comes from skb->data.
114 */
115 if (req->src != req->dst)
116 for (sg = sg_next(req->src); sg; sg = sg_next(sg))
117 put_page(sg_page(sg));
118}
119
120static void esp_output_done(struct crypto_async_request *base, int err)
121{
122 struct sk_buff *skb = base->data;
123 struct xfrm_offload *xo = xfrm_offload(skb);
124 void *tmp;
125 struct xfrm_state *x;
126
127 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
128 struct sec_path *sp = skb_sec_path(skb);
129
130 x = sp->xvec[sp->len - 1];
131 } else {
132 x = skb_dst(skb)->xfrm;
133 }
134
135 tmp = ESP_SKB_CB(skb)->tmp;
136 esp_ssg_unref(x, tmp);
137 kfree(tmp);
138
139 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
140 if (err) {
141 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
142 kfree_skb(skb);
143 return;
144 }
145
146 skb_push(skb, skb->data - skb_mac_header(skb));
147 secpath_reset(skb);
148 xfrm_dev_resume(skb);
149 } else {
150 xfrm_output_resume(skb, err);
151 }
152}
153
154/* Move ESP header back into place. */
155static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
156{
157 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
158 void *tmp = ESP_SKB_CB(skb)->tmp;
159 __be32 *seqhi = esp_tmp_extra(tmp);
160
161 esph->seq_no = esph->spi;
162 esph->spi = *seqhi;
163}
164
165static void esp_output_restore_header(struct sk_buff *skb)
166{
167 void *tmp = ESP_SKB_CB(skb)->tmp;
168 struct esp_output_extra *extra = esp_tmp_extra(tmp);
169
170 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
171 sizeof(__be32));
172}
173
174static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
175 struct xfrm_state *x,
176 struct ip_esp_hdr *esph,
177 struct esp_output_extra *extra)
178{
179 /* For ESN we move the header forward by 4 bytes to
180 * accomodate the high bits. We will move it back after
181 * encryption.
182 */
183 if ((x->props.flags & XFRM_STATE_ESN)) {
184 __u32 seqhi;
185 struct xfrm_offload *xo = xfrm_offload(skb);
186
187 if (xo)
188 seqhi = xo->seq.hi;
189 else
190 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
191
192 extra->esphoff = (unsigned char *)esph -
193 skb_transport_header(skb);
194 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
195 extra->seqhi = esph->spi;
196 esph->seq_no = htonl(seqhi);
197 }
198
199 esph->spi = x->id.spi;
200
201 return esph;
202}
203
204static void esp_output_done_esn(struct crypto_async_request *base, int err)
205{
206 struct sk_buff *skb = base->data;
207
208 esp_output_restore_header(skb);
209 esp_output_done(base, err);
210}
211
212static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto)
213{
214 /* Fill padding... */
215 if (tfclen) {
216 memset(tail, 0, tfclen);
217 tail += tfclen;
218 }
219 do {
220 int i;
221 for (i = 0; i < plen - 2; i++)
222 tail[i] = i + 1;
223 } while (0);
224 tail[plen - 2] = plen - 2;
225 tail[plen - 1] = proto;
226}
227
228static int esp_output_udp_encap(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
229{
230 int encap_type;
231 struct udphdr *uh;
232 __be32 *udpdata32;
233 __be16 sport, dport;
234 struct xfrm_encap_tmpl *encap = x->encap;
235 struct ip_esp_hdr *esph = esp->esph;
236 unsigned int len;
237
238 spin_lock_bh(&x->lock);
239 sport = encap->encap_sport;
240 dport = encap->encap_dport;
241 encap_type = encap->encap_type;
242 spin_unlock_bh(&x->lock);
243
244 len = skb->len + esp->tailen - skb_transport_offset(skb);
245 if (len + sizeof(struct iphdr) >= IP_MAX_MTU)
246 return -EMSGSIZE;
247
248 uh = (struct udphdr *)esph;
249 uh->source = sport;
250 uh->dest = dport;
251 uh->len = htons(len);
252 uh->check = 0;
253
254 switch (encap_type) {
255 default:
256 case UDP_ENCAP_ESPINUDP:
257 esph = (struct ip_esp_hdr *)(uh + 1);
258 break;
259 case UDP_ENCAP_ESPINUDP_NON_IKE:
260 udpdata32 = (__be32 *)(uh + 1);
261 udpdata32[0] = udpdata32[1] = 0;
262 esph = (struct ip_esp_hdr *)(udpdata32 + 2);
263 break;
264 }
265
266 *skb_mac_header(skb) = IPPROTO_UDP;
267 esp->esph = esph;
268
269 return 0;
270}
271
272int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
273{
274 u8 *tail;
275 u8 *vaddr;
276 int nfrags;
277 int esph_offset;
278 struct page *page;
279 struct sk_buff *trailer;
280 int tailen = esp->tailen;
281
282 /* this is non-NULL only with UDP Encapsulation */
283 if (x->encap) {
284 int err = esp_output_udp_encap(x, skb, esp);
285
286 if (err < 0)
287 return err;
288 }
289
290 if (!skb_cloned(skb)) {
291 if (tailen <= skb_tailroom(skb)) {
292 nfrags = 1;
293 trailer = skb;
294 tail = skb_tail_pointer(trailer);
295
296 goto skip_cow;
297 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
298 && !skb_has_frag_list(skb)) {
299 int allocsize;
300 struct sock *sk = skb->sk;
301 struct page_frag *pfrag = &x->xfrag;
302
303 esp->inplace = false;
304
305 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
306
307 spin_lock_bh(&x->lock);
308
309 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
310 spin_unlock_bh(&x->lock);
311 goto cow;
312 }
313
314 page = pfrag->page;
315 get_page(page);
316
317 vaddr = kmap_atomic(page);
318
319 tail = vaddr + pfrag->offset;
320
321 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
322
323 kunmap_atomic(vaddr);
324
325 nfrags = skb_shinfo(skb)->nr_frags;
326
327 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
328 tailen);
329 skb_shinfo(skb)->nr_frags = ++nfrags;
330
331 pfrag->offset = pfrag->offset + allocsize;
332
333 spin_unlock_bh(&x->lock);
334
335 nfrags++;
336
337 skb->len += tailen;
338 skb->data_len += tailen;
339 skb->truesize += tailen;
340 if (sk && sk_fullsock(sk))
341 refcount_add(tailen, &sk->sk_wmem_alloc);
342
343 goto out;
344 }
345 }
346
347cow:
348 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
349
350 nfrags = skb_cow_data(skb, tailen, &trailer);
351 if (nfrags < 0)
352 goto out;
353 tail = skb_tail_pointer(trailer);
354 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
355
356skip_cow:
357 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
358 pskb_put(skb, trailer, tailen);
359
360out:
361 return nfrags;
362}
363EXPORT_SYMBOL_GPL(esp_output_head);
364
365int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
366{
367 u8 *iv;
368 int alen;
369 void *tmp;
370 int ivlen;
371 int assoclen;
372 int extralen;
373 struct page *page;
374 struct ip_esp_hdr *esph;
375 struct crypto_aead *aead;
376 struct aead_request *req;
377 struct scatterlist *sg, *dsg;
378 struct esp_output_extra *extra;
379 int err = -ENOMEM;
380
381 assoclen = sizeof(struct ip_esp_hdr);
382 extralen = 0;
383
384 if (x->props.flags & XFRM_STATE_ESN) {
385 extralen += sizeof(*extra);
386 assoclen += sizeof(__be32);
387 }
388
389 aead = x->data;
390 alen = crypto_aead_authsize(aead);
391 ivlen = crypto_aead_ivsize(aead);
392
393 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
394 if (!tmp)
395 goto error;
396
397 extra = esp_tmp_extra(tmp);
398 iv = esp_tmp_iv(aead, tmp, extralen);
399 req = esp_tmp_req(aead, iv);
400 sg = esp_req_sg(aead, req);
401
402 if (esp->inplace)
403 dsg = sg;
404 else
405 dsg = &sg[esp->nfrags];
406
407 esph = esp_output_set_extra(skb, x, esp->esph, extra);
408 esp->esph = esph;
409
410 sg_init_table(sg, esp->nfrags);
411 err = skb_to_sgvec(skb, sg,
412 (unsigned char *)esph - skb->data,
413 assoclen + ivlen + esp->clen + alen);
414 if (unlikely(err < 0))
415 goto error_free;
416
417 if (!esp->inplace) {
418 int allocsize;
419 struct page_frag *pfrag = &x->xfrag;
420
421 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
422
423 spin_lock_bh(&x->lock);
424 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
425 spin_unlock_bh(&x->lock);
426 goto error_free;
427 }
428
429 skb_shinfo(skb)->nr_frags = 1;
430
431 page = pfrag->page;
432 get_page(page);
433 /* replace page frags in skb with new page */
434 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
435 pfrag->offset = pfrag->offset + allocsize;
436 spin_unlock_bh(&x->lock);
437
438 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
439 err = skb_to_sgvec(skb, dsg,
440 (unsigned char *)esph - skb->data,
441 assoclen + ivlen + esp->clen + alen);
442 if (unlikely(err < 0))
443 goto error_free;
444 }
445
446 if ((x->props.flags & XFRM_STATE_ESN))
447 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
448 else
449 aead_request_set_callback(req, 0, esp_output_done, skb);
450
451 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
452 aead_request_set_ad(req, assoclen);
453
454 memset(iv, 0, ivlen);
455 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
456 min(ivlen, 8));
457
458 ESP_SKB_CB(skb)->tmp = tmp;
459 err = crypto_aead_encrypt(req);
460
461 switch (err) {
462 case -EINPROGRESS:
463 goto error;
464
465 case -ENOSPC:
466 err = NET_XMIT_DROP;
467 break;
468
469 case 0:
470 if ((x->props.flags & XFRM_STATE_ESN))
471 esp_output_restore_header(skb);
472 }
473
474 if (sg != dsg)
475 esp_ssg_unref(x, tmp);
476
477error_free:
478 kfree(tmp);
479error:
480 return err;
481}
482EXPORT_SYMBOL_GPL(esp_output_tail);
483
484static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
485{
486 int alen;
487 int blksize;
488 struct ip_esp_hdr *esph;
489 struct crypto_aead *aead;
490 struct esp_info esp;
491
492 esp.inplace = true;
493
494 esp.proto = *skb_mac_header(skb);
495 *skb_mac_header(skb) = IPPROTO_ESP;
496
497 /* skb is pure payload to encrypt */
498
499 aead = x->data;
500 alen = crypto_aead_authsize(aead);
501
502 esp.tfclen = 0;
503 if (x->tfcpad) {
504 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
505 u32 padto;
506
507 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
508 if (skb->len < padto)
509 esp.tfclen = padto - skb->len;
510 }
511 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
512 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
513 esp.plen = esp.clen - skb->len - esp.tfclen;
514 esp.tailen = esp.tfclen + esp.plen + alen;
515
516 esp.esph = ip_esp_hdr(skb);
517
518 esp.nfrags = esp_output_head(x, skb, &esp);
519 if (esp.nfrags < 0)
520 return esp.nfrags;
521
522 esph = esp.esph;
523 esph->spi = x->id.spi;
524
525 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
526 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
527 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
528
529 skb_push(skb, -skb_network_offset(skb));
530
531 return esp_output_tail(x, skb, &esp);
532}
533
534static inline int esp_remove_trailer(struct sk_buff *skb)
535{
536 struct xfrm_state *x = xfrm_input_state(skb);
537 struct xfrm_offload *xo = xfrm_offload(skb);
538 struct crypto_aead *aead = x->data;
539 int alen, hlen, elen;
540 int padlen, trimlen;
541 __wsum csumdiff;
542 u8 nexthdr[2];
543 int ret;
544
545 alen = crypto_aead_authsize(aead);
546 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
547 elen = skb->len - hlen;
548
549 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) {
550 ret = xo->proto;
551 goto out;
552 }
553
554 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
555 BUG();
556
557 ret = -EINVAL;
558 padlen = nexthdr[0];
559 if (padlen + 2 + alen >= elen) {
560 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
561 padlen + 2, elen - alen);
562 goto out;
563 }
564
565 trimlen = alen + padlen + 2;
566 if (skb->ip_summed == CHECKSUM_COMPLETE) {
567 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
568 skb->csum = csum_block_sub(skb->csum, csumdiff,
569 skb->len - trimlen);
570 }
571 pskb_trim(skb, skb->len - trimlen);
572
573 ret = nexthdr[1];
574
575out:
576 return ret;
577}
578
579int esp_input_done2(struct sk_buff *skb, int err)
580{
581 const struct iphdr *iph;
582 struct xfrm_state *x = xfrm_input_state(skb);
583 struct xfrm_offload *xo = xfrm_offload(skb);
584 struct crypto_aead *aead = x->data;
585 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
586 int ihl;
587
588 if (!xo || (xo && !(xo->flags & CRYPTO_DONE)))
589 kfree(ESP_SKB_CB(skb)->tmp);
590
591 if (unlikely(err))
592 goto out;
593
594 err = esp_remove_trailer(skb);
595 if (unlikely(err < 0))
596 goto out;
597
598 iph = ip_hdr(skb);
599 ihl = iph->ihl * 4;
600
601 if (x->encap) {
602 struct xfrm_encap_tmpl *encap = x->encap;
603 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
604
605 /*
606 * 1) if the NAT-T peer's IP or port changed then
607 * advertize the change to the keying daemon.
608 * This is an inbound SA, so just compare
609 * SRC ports.
610 */
611 if (iph->saddr != x->props.saddr.a4 ||
612 uh->source != encap->encap_sport) {
613 xfrm_address_t ipaddr;
614
615 ipaddr.a4 = iph->saddr;
616 km_new_mapping(x, &ipaddr, uh->source);
617
618 /* XXX: perhaps add an extra
619 * policy check here, to see
620 * if we should allow or
621 * reject a packet from a
622 * different source
623 * address/port.
624 */
625 }
626
627 /*
628 * 2) ignore UDP/TCP checksums in case
629 * of NAT-T in Transport Mode, or
630 * perform other post-processing fixes
631 * as per draft-ietf-ipsec-udp-encaps-06,
632 * section 3.1.2
633 */
634 if (x->props.mode == XFRM_MODE_TRANSPORT)
635 skb->ip_summed = CHECKSUM_UNNECESSARY;
636 }
637
638 skb_pull_rcsum(skb, hlen);
639 if (x->props.mode == XFRM_MODE_TUNNEL)
640 skb_reset_transport_header(skb);
641 else
642 skb_set_transport_header(skb, -ihl);
643
644 /* RFC4303: Drop dummy packets without any error */
645 if (err == IPPROTO_NONE)
646 err = -EINVAL;
647
648out:
649 return err;
650}
651EXPORT_SYMBOL_GPL(esp_input_done2);
652
653static void esp_input_done(struct crypto_async_request *base, int err)
654{
655 struct sk_buff *skb = base->data;
656
657 xfrm_input_resume(skb, esp_input_done2(skb, err));
658}
659
660static void esp_input_restore_header(struct sk_buff *skb)
661{
662 esp_restore_header(skb, 0);
663 __skb_pull(skb, 4);
664}
665
666static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
667{
668 struct xfrm_state *x = xfrm_input_state(skb);
669 struct ip_esp_hdr *esph;
670
671 /* For ESN we move the header forward by 4 bytes to
672 * accomodate the high bits. We will move it back after
673 * decryption.
674 */
675 if ((x->props.flags & XFRM_STATE_ESN)) {
676 esph = skb_push(skb, 4);
677 *seqhi = esph->spi;
678 esph->spi = esph->seq_no;
679 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
680 }
681}
682
683static void esp_input_done_esn(struct crypto_async_request *base, int err)
684{
685 struct sk_buff *skb = base->data;
686
687 esp_input_restore_header(skb);
688 esp_input_done(base, err);
689}
690
691/*
692 * Note: detecting truncated vs. non-truncated authentication data is very
693 * expensive, so we only support truncated data, which is the recommended
694 * and common case.
695 */
696static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
697{
698 struct crypto_aead *aead = x->data;
699 struct aead_request *req;
700 struct sk_buff *trailer;
701 int ivlen = crypto_aead_ivsize(aead);
702 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
703 int nfrags;
704 int assoclen;
705 int seqhilen;
706 __be32 *seqhi;
707 void *tmp;
708 u8 *iv;
709 struct scatterlist *sg;
710 int err = -EINVAL;
711
712 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
713 goto out;
714
715 if (elen <= 0)
716 goto out;
717
718 assoclen = sizeof(struct ip_esp_hdr);
719 seqhilen = 0;
720
721 if (x->props.flags & XFRM_STATE_ESN) {
722 seqhilen += sizeof(__be32);
723 assoclen += seqhilen;
724 }
725
726 if (!skb_cloned(skb)) {
727 if (!skb_is_nonlinear(skb)) {
728 nfrags = 1;
729
730 goto skip_cow;
731 } else if (!skb_has_frag_list(skb)) {
732 nfrags = skb_shinfo(skb)->nr_frags;
733 nfrags++;
734
735 goto skip_cow;
736 }
737 }
738
739 err = skb_cow_data(skb, 0, &trailer);
740 if (err < 0)
741 goto out;
742
743 nfrags = err;
744
745skip_cow:
746 err = -ENOMEM;
747 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
748 if (!tmp)
749 goto out;
750
751 ESP_SKB_CB(skb)->tmp = tmp;
752 seqhi = esp_tmp_extra(tmp);
753 iv = esp_tmp_iv(aead, tmp, seqhilen);
754 req = esp_tmp_req(aead, iv);
755 sg = esp_req_sg(aead, req);
756
757 esp_input_set_header(skb, seqhi);
758
759 sg_init_table(sg, nfrags);
760 err = skb_to_sgvec(skb, sg, 0, skb->len);
761 if (unlikely(err < 0)) {
762 kfree(tmp);
763 goto out;
764 }
765
766 skb->ip_summed = CHECKSUM_NONE;
767
768 if ((x->props.flags & XFRM_STATE_ESN))
769 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
770 else
771 aead_request_set_callback(req, 0, esp_input_done, skb);
772
773 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
774 aead_request_set_ad(req, assoclen);
775
776 err = crypto_aead_decrypt(req);
777 if (err == -EINPROGRESS)
778 goto out;
779
780 if ((x->props.flags & XFRM_STATE_ESN))
781 esp_input_restore_header(skb);
782
783 err = esp_input_done2(skb, err);
784
785out:
786 return err;
787}
788
789static int esp4_err(struct sk_buff *skb, u32 info)
790{
791 struct net *net = dev_net(skb->dev);
792 const struct iphdr *iph = (const struct iphdr *)skb->data;
793 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
794 struct xfrm_state *x;
795
796 switch (icmp_hdr(skb)->type) {
797 case ICMP_DEST_UNREACH:
798 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
799 return 0;
800 case ICMP_REDIRECT:
801 break;
802 default:
803 return 0;
804 }
805
806 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
807 esph->spi, IPPROTO_ESP, AF_INET);
808 if (!x)
809 return 0;
810
811 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
812 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP);
813 else
814 ipv4_redirect(skb, net, 0, IPPROTO_ESP);
815 xfrm_state_put(x);
816
817 return 0;
818}
819
820static void esp_destroy(struct xfrm_state *x)
821{
822 struct crypto_aead *aead = x->data;
823
824 if (!aead)
825 return;
826
827 crypto_free_aead(aead);
828}
829
830static int esp_init_aead(struct xfrm_state *x)
831{
832 char aead_name[CRYPTO_MAX_ALG_NAME];
833 struct crypto_aead *aead;
834 int err;
835
836 err = -ENAMETOOLONG;
837 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
838 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
839 goto error;
840
841 aead = crypto_alloc_aead(aead_name, 0, 0);
842 err = PTR_ERR(aead);
843 if (IS_ERR(aead))
844 goto error;
845
846 x->data = aead;
847
848 err = crypto_aead_setkey(aead, x->aead->alg_key,
849 (x->aead->alg_key_len + 7) / 8);
850 if (err)
851 goto error;
852
853 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
854 if (err)
855 goto error;
856
857error:
858 return err;
859}
860
861static int esp_init_authenc(struct xfrm_state *x)
862{
863 struct crypto_aead *aead;
864 struct crypto_authenc_key_param *param;
865 struct rtattr *rta;
866 char *key;
867 char *p;
868 char authenc_name[CRYPTO_MAX_ALG_NAME];
869 unsigned int keylen;
870 int err;
871
872 err = -EINVAL;
873 if (!x->ealg)
874 goto error;
875
876 err = -ENAMETOOLONG;
877
878 if ((x->props.flags & XFRM_STATE_ESN)) {
879 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
880 "%s%sauthencesn(%s,%s)%s",
881 x->geniv ?: "", x->geniv ? "(" : "",
882 x->aalg ? x->aalg->alg_name : "digest_null",
883 x->ealg->alg_name,
884 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
885 goto error;
886 } else {
887 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
888 "%s%sauthenc(%s,%s)%s",
889 x->geniv ?: "", x->geniv ? "(" : "",
890 x->aalg ? x->aalg->alg_name : "digest_null",
891 x->ealg->alg_name,
892 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
893 goto error;
894 }
895
896 aead = crypto_alloc_aead(authenc_name, 0, 0);
897 err = PTR_ERR(aead);
898 if (IS_ERR(aead))
899 goto error;
900
901 x->data = aead;
902
903 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
904 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
905 err = -ENOMEM;
906 key = kmalloc(keylen, GFP_KERNEL);
907 if (!key)
908 goto error;
909
910 p = key;
911 rta = (void *)p;
912 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
913 rta->rta_len = RTA_LENGTH(sizeof(*param));
914 param = RTA_DATA(rta);
915 p += RTA_SPACE(sizeof(*param));
916
917 if (x->aalg) {
918 struct xfrm_algo_desc *aalg_desc;
919
920 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
921 p += (x->aalg->alg_key_len + 7) / 8;
922
923 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
924 BUG_ON(!aalg_desc);
925
926 err = -EINVAL;
927 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
928 crypto_aead_authsize(aead)) {
929 pr_info("ESP: %s digestsize %u != %hu\n",
930 x->aalg->alg_name,
931 crypto_aead_authsize(aead),
932 aalg_desc->uinfo.auth.icv_fullbits / 8);
933 goto free_key;
934 }
935
936 err = crypto_aead_setauthsize(
937 aead, x->aalg->alg_trunc_len / 8);
938 if (err)
939 goto free_key;
940 }
941
942 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
943 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
944
945 err = crypto_aead_setkey(aead, key, keylen);
946
947free_key:
948 kfree(key);
949
950error:
951 return err;
952}
953
954static int esp_init_state(struct xfrm_state *x)
955{
956 struct crypto_aead *aead;
957 u32 align;
958 int err;
959
960 x->data = NULL;
961
962 if (x->aead)
963 err = esp_init_aead(x);
964 else
965 err = esp_init_authenc(x);
966
967 if (err)
968 goto error;
969
970 aead = x->data;
971
972 x->props.header_len = sizeof(struct ip_esp_hdr) +
973 crypto_aead_ivsize(aead);
974 if (x->props.mode == XFRM_MODE_TUNNEL)
975 x->props.header_len += sizeof(struct iphdr);
976 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
977 x->props.header_len += IPV4_BEET_PHMAXLEN;
978 if (x->encap) {
979 struct xfrm_encap_tmpl *encap = x->encap;
980
981 switch (encap->encap_type) {
982 default:
983 err = -EINVAL;
984 goto error;
985 case UDP_ENCAP_ESPINUDP:
986 x->props.header_len += sizeof(struct udphdr);
987 break;
988 case UDP_ENCAP_ESPINUDP_NON_IKE:
989 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
990 break;
991 }
992 }
993
994 align = ALIGN(crypto_aead_blocksize(aead), 4);
995 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
996
997error:
998 return err;
999}
1000
1001static int esp4_rcv_cb(struct sk_buff *skb, int err)
1002{
1003 return 0;
1004}
1005
1006static const struct xfrm_type esp_type =
1007{
1008 .description = "ESP4",
1009 .owner = THIS_MODULE,
1010 .proto = IPPROTO_ESP,
1011 .flags = XFRM_TYPE_REPLAY_PROT,
1012 .init_state = esp_init_state,
1013 .destructor = esp_destroy,
1014 .input = esp_input,
1015 .output = esp_output,
1016};
1017
1018static struct xfrm4_protocol esp4_protocol = {
1019 .handler = xfrm4_rcv,
1020 .input_handler = xfrm_input,
1021 .cb_handler = esp4_rcv_cb,
1022 .err_handler = esp4_err,
1023 .priority = 0,
1024};
1025
1026static int __init esp4_init(void)
1027{
1028 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1029 pr_info("%s: can't add xfrm type\n", __func__);
1030 return -EAGAIN;
1031 }
1032 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1033 pr_info("%s: can't add protocol\n", __func__);
1034 xfrm_unregister_type(&esp_type, AF_INET);
1035 return -EAGAIN;
1036 }
1037 return 0;
1038}
1039
1040static void __exit esp4_fini(void)
1041{
1042 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1043 pr_info("%s: can't remove protocol\n", __func__);
1044 xfrm_unregister_type(&esp_type, AF_INET);
1045}
1046
1047module_init(esp4_init);
1048module_exit(esp4_fini);
1049MODULE_LICENSE("GPL");
1050MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);