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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#include <net/tcp.h>
22#include <net/espintcp.h>
23
24#include <linux/highmem.h>
25
26struct esp_skb_cb {
27 struct xfrm_skb_cb xfrm;
28 void *tmp;
29};
30
31struct esp_output_extra {
32 __be32 seqhi;
33 u32 esphoff;
34};
35
36#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
37
38/*
39 * Allocate an AEAD request structure with extra space for SG and IV.
40 *
41 * For alignment considerations the IV is placed at the front, followed
42 * by the request and finally the SG list.
43 *
44 * TODO: Use spare space in skb for this where possible.
45 */
46static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen)
47{
48 unsigned int len;
49
50 len = extralen;
51
52 len += crypto_aead_ivsize(aead);
53
54 if (len) {
55 len += crypto_aead_alignmask(aead) &
56 ~(crypto_tfm_ctx_alignment() - 1);
57 len = ALIGN(len, crypto_tfm_ctx_alignment());
58 }
59
60 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
61 len = ALIGN(len, __alignof__(struct scatterlist));
62
63 len += sizeof(struct scatterlist) * nfrags;
64
65 return kmalloc(len, GFP_ATOMIC);
66}
67
68static inline void *esp_tmp_extra(void *tmp)
69{
70 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
71}
72
73static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen)
74{
75 return crypto_aead_ivsize(aead) ?
76 PTR_ALIGN((u8 *)tmp + extralen,
77 crypto_aead_alignmask(aead) + 1) : tmp + extralen;
78}
79
80static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
81{
82 struct aead_request *req;
83
84 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
85 crypto_tfm_ctx_alignment());
86 aead_request_set_tfm(req, aead);
87 return req;
88}
89
90static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
91 struct aead_request *req)
92{
93 return (void *)ALIGN((unsigned long)(req + 1) +
94 crypto_aead_reqsize(aead),
95 __alignof__(struct scatterlist));
96}
97
98static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
99{
100 struct esp_output_extra *extra = esp_tmp_extra(tmp);
101 struct crypto_aead *aead = x->data;
102 int extralen = 0;
103 u8 *iv;
104 struct aead_request *req;
105 struct scatterlist *sg;
106
107 if (x->props.flags & XFRM_STATE_ESN)
108 extralen += sizeof(*extra);
109
110 extra = esp_tmp_extra(tmp);
111 iv = esp_tmp_iv(aead, tmp, extralen);
112 req = esp_tmp_req(aead, iv);
113
114 /* Unref skb_frag_pages in the src scatterlist if necessary.
115 * Skip the first sg which comes from skb->data.
116 */
117 if (req->src != req->dst)
118 for (sg = sg_next(req->src); sg; sg = sg_next(sg))
119 put_page(sg_page(sg));
120}
121
122#ifdef CONFIG_INET_ESPINTCP
123struct esp_tcp_sk {
124 struct sock *sk;
125 struct rcu_head rcu;
126};
127
128static void esp_free_tcp_sk(struct rcu_head *head)
129{
130 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu);
131
132 sock_put(esk->sk);
133 kfree(esk);
134}
135
136static struct sock *esp_find_tcp_sk(struct xfrm_state *x)
137{
138 struct xfrm_encap_tmpl *encap = x->encap;
139 struct esp_tcp_sk *esk;
140 __be16 sport, dport;
141 struct sock *nsk;
142 struct sock *sk;
143
144 sk = rcu_dereference(x->encap_sk);
145 if (sk && sk->sk_state == TCP_ESTABLISHED)
146 return sk;
147
148 spin_lock_bh(&x->lock);
149 sport = encap->encap_sport;
150 dport = encap->encap_dport;
151 nsk = rcu_dereference_protected(x->encap_sk,
152 lockdep_is_held(&x->lock));
153 if (sk && sk == nsk) {
154 esk = kmalloc(sizeof(*esk), GFP_ATOMIC);
155 if (!esk) {
156 spin_unlock_bh(&x->lock);
157 return ERR_PTR(-ENOMEM);
158 }
159 RCU_INIT_POINTER(x->encap_sk, NULL);
160 esk->sk = sk;
161 call_rcu(&esk->rcu, esp_free_tcp_sk);
162 }
163 spin_unlock_bh(&x->lock);
164
165 sk = inet_lookup_established(xs_net(x), &tcp_hashinfo, x->id.daddr.a4,
166 dport, x->props.saddr.a4, sport, 0);
167 if (!sk)
168 return ERR_PTR(-ENOENT);
169
170 if (!tcp_is_ulp_esp(sk)) {
171 sock_put(sk);
172 return ERR_PTR(-EINVAL);
173 }
174
175 spin_lock_bh(&x->lock);
176 nsk = rcu_dereference_protected(x->encap_sk,
177 lockdep_is_held(&x->lock));
178 if (encap->encap_sport != sport ||
179 encap->encap_dport != dport) {
180 sock_put(sk);
181 sk = nsk ?: ERR_PTR(-EREMCHG);
182 } else if (sk == nsk) {
183 sock_put(sk);
184 } else {
185 rcu_assign_pointer(x->encap_sk, sk);
186 }
187 spin_unlock_bh(&x->lock);
188
189 return sk;
190}
191
192static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
193{
194 struct sock *sk;
195 int err;
196
197 rcu_read_lock();
198
199 sk = esp_find_tcp_sk(x);
200 err = PTR_ERR_OR_ZERO(sk);
201 if (err)
202 goto out;
203
204 bh_lock_sock(sk);
205 if (sock_owned_by_user(sk))
206 err = espintcp_queue_out(sk, skb);
207 else
208 err = espintcp_push_skb(sk, skb);
209 bh_unlock_sock(sk);
210
211out:
212 rcu_read_unlock();
213 return err;
214}
215
216static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
217 struct sk_buff *skb)
218{
219 struct dst_entry *dst = skb_dst(skb);
220 struct xfrm_state *x = dst->xfrm;
221
222 return esp_output_tcp_finish(x, skb);
223}
224
225static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
226{
227 int err;
228
229 local_bh_disable();
230 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
231 local_bh_enable();
232
233 /* EINPROGRESS just happens to do the right thing. It
234 * actually means that the skb has been consumed and
235 * isn't coming back.
236 */
237 return err ?: -EINPROGRESS;
238}
239#else
240static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
241{
242 kfree_skb(skb);
243
244 return -EOPNOTSUPP;
245}
246#endif
247
248static void esp_output_done(struct crypto_async_request *base, int err)
249{
250 struct sk_buff *skb = base->data;
251 struct xfrm_offload *xo = xfrm_offload(skb);
252 void *tmp;
253 struct xfrm_state *x;
254
255 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
256 struct sec_path *sp = skb_sec_path(skb);
257
258 x = sp->xvec[sp->len - 1];
259 } else {
260 x = skb_dst(skb)->xfrm;
261 }
262
263 tmp = ESP_SKB_CB(skb)->tmp;
264 esp_ssg_unref(x, tmp);
265 kfree(tmp);
266
267 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
268 if (err) {
269 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
270 kfree_skb(skb);
271 return;
272 }
273
274 skb_push(skb, skb->data - skb_mac_header(skb));
275 secpath_reset(skb);
276 xfrm_dev_resume(skb);
277 } else {
278 if (!err &&
279 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
280 esp_output_tail_tcp(x, skb);
281 else
282 xfrm_output_resume(skb, err);
283 }
284}
285
286/* Move ESP header back into place. */
287static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
288{
289 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
290 void *tmp = ESP_SKB_CB(skb)->tmp;
291 __be32 *seqhi = esp_tmp_extra(tmp);
292
293 esph->seq_no = esph->spi;
294 esph->spi = *seqhi;
295}
296
297static void esp_output_restore_header(struct sk_buff *skb)
298{
299 void *tmp = ESP_SKB_CB(skb)->tmp;
300 struct esp_output_extra *extra = esp_tmp_extra(tmp);
301
302 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
303 sizeof(__be32));
304}
305
306static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
307 struct xfrm_state *x,
308 struct ip_esp_hdr *esph,
309 struct esp_output_extra *extra)
310{
311 /* For ESN we move the header forward by 4 bytes to
312 * accomodate the high bits. We will move it back after
313 * encryption.
314 */
315 if ((x->props.flags & XFRM_STATE_ESN)) {
316 __u32 seqhi;
317 struct xfrm_offload *xo = xfrm_offload(skb);
318
319 if (xo)
320 seqhi = xo->seq.hi;
321 else
322 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
323
324 extra->esphoff = (unsigned char *)esph -
325 skb_transport_header(skb);
326 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
327 extra->seqhi = esph->spi;
328 esph->seq_no = htonl(seqhi);
329 }
330
331 esph->spi = x->id.spi;
332
333 return esph;
334}
335
336static void esp_output_done_esn(struct crypto_async_request *base, int err)
337{
338 struct sk_buff *skb = base->data;
339
340 esp_output_restore_header(skb);
341 esp_output_done(base, err);
342}
343
344static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb,
345 int encap_type,
346 struct esp_info *esp,
347 __be16 sport,
348 __be16 dport)
349{
350 struct udphdr *uh;
351 __be32 *udpdata32;
352 unsigned int len;
353
354 len = skb->len + esp->tailen - skb_transport_offset(skb);
355 if (len + sizeof(struct iphdr) > IP_MAX_MTU)
356 return ERR_PTR(-EMSGSIZE);
357
358 uh = (struct udphdr *)esp->esph;
359 uh->source = sport;
360 uh->dest = dport;
361 uh->len = htons(len);
362 uh->check = 0;
363
364 *skb_mac_header(skb) = IPPROTO_UDP;
365
366 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
367 udpdata32 = (__be32 *)(uh + 1);
368 udpdata32[0] = udpdata32[1] = 0;
369 return (struct ip_esp_hdr *)(udpdata32 + 2);
370 }
371
372 return (struct ip_esp_hdr *)(uh + 1);
373}
374
375#ifdef CONFIG_INET_ESPINTCP
376static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
377 struct sk_buff *skb,
378 struct esp_info *esp)
379{
380 __be16 *lenp = (void *)esp->esph;
381 struct ip_esp_hdr *esph;
382 unsigned int len;
383 struct sock *sk;
384
385 len = skb->len + esp->tailen - skb_transport_offset(skb);
386 if (len > IP_MAX_MTU)
387 return ERR_PTR(-EMSGSIZE);
388
389 rcu_read_lock();
390 sk = esp_find_tcp_sk(x);
391 rcu_read_unlock();
392
393 if (IS_ERR(sk))
394 return ERR_CAST(sk);
395
396 *lenp = htons(len);
397 esph = (struct ip_esp_hdr *)(lenp + 1);
398
399 return esph;
400}
401#else
402static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
403 struct sk_buff *skb,
404 struct esp_info *esp)
405{
406 return ERR_PTR(-EOPNOTSUPP);
407}
408#endif
409
410static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb,
411 struct esp_info *esp)
412{
413 struct xfrm_encap_tmpl *encap = x->encap;
414 struct ip_esp_hdr *esph;
415 __be16 sport, dport;
416 int encap_type;
417
418 spin_lock_bh(&x->lock);
419 sport = encap->encap_sport;
420 dport = encap->encap_dport;
421 encap_type = encap->encap_type;
422 spin_unlock_bh(&x->lock);
423
424 switch (encap_type) {
425 default:
426 case UDP_ENCAP_ESPINUDP:
427 case UDP_ENCAP_ESPINUDP_NON_IKE:
428 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport);
429 break;
430 case TCP_ENCAP_ESPINTCP:
431 esph = esp_output_tcp_encap(x, skb, esp);
432 break;
433 }
434
435 if (IS_ERR(esph))
436 return PTR_ERR(esph);
437
438 esp->esph = esph;
439
440 return 0;
441}
442
443int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
444{
445 u8 *tail;
446 u8 *vaddr;
447 int nfrags;
448 int esph_offset;
449 struct page *page;
450 struct sk_buff *trailer;
451 int tailen = esp->tailen;
452
453 /* this is non-NULL only with TCP/UDP Encapsulation */
454 if (x->encap) {
455 int err = esp_output_encap(x, skb, esp);
456
457 if (err < 0)
458 return err;
459 }
460
461 if (!skb_cloned(skb)) {
462 if (tailen <= skb_tailroom(skb)) {
463 nfrags = 1;
464 trailer = skb;
465 tail = skb_tail_pointer(trailer);
466
467 goto skip_cow;
468 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
469 && !skb_has_frag_list(skb)) {
470 int allocsize;
471 struct sock *sk = skb->sk;
472 struct page_frag *pfrag = &x->xfrag;
473
474 esp->inplace = false;
475
476 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
477
478 spin_lock_bh(&x->lock);
479
480 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
481 spin_unlock_bh(&x->lock);
482 goto cow;
483 }
484
485 page = pfrag->page;
486 get_page(page);
487
488 vaddr = kmap_atomic(page);
489
490 tail = vaddr + pfrag->offset;
491
492 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
493
494 kunmap_atomic(vaddr);
495
496 nfrags = skb_shinfo(skb)->nr_frags;
497
498 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
499 tailen);
500 skb_shinfo(skb)->nr_frags = ++nfrags;
501
502 pfrag->offset = pfrag->offset + allocsize;
503
504 spin_unlock_bh(&x->lock);
505
506 nfrags++;
507
508 skb->len += tailen;
509 skb->data_len += tailen;
510 skb->truesize += tailen;
511 if (sk && sk_fullsock(sk))
512 refcount_add(tailen, &sk->sk_wmem_alloc);
513
514 goto out;
515 }
516 }
517
518cow:
519 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
520
521 nfrags = skb_cow_data(skb, tailen, &trailer);
522 if (nfrags < 0)
523 goto out;
524 tail = skb_tail_pointer(trailer);
525 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
526
527skip_cow:
528 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
529 pskb_put(skb, trailer, tailen);
530
531out:
532 return nfrags;
533}
534EXPORT_SYMBOL_GPL(esp_output_head);
535
536int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
537{
538 u8 *iv;
539 int alen;
540 void *tmp;
541 int ivlen;
542 int assoclen;
543 int extralen;
544 struct page *page;
545 struct ip_esp_hdr *esph;
546 struct crypto_aead *aead;
547 struct aead_request *req;
548 struct scatterlist *sg, *dsg;
549 struct esp_output_extra *extra;
550 int err = -ENOMEM;
551
552 assoclen = sizeof(struct ip_esp_hdr);
553 extralen = 0;
554
555 if (x->props.flags & XFRM_STATE_ESN) {
556 extralen += sizeof(*extra);
557 assoclen += sizeof(__be32);
558 }
559
560 aead = x->data;
561 alen = crypto_aead_authsize(aead);
562 ivlen = crypto_aead_ivsize(aead);
563
564 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
565 if (!tmp)
566 goto error;
567
568 extra = esp_tmp_extra(tmp);
569 iv = esp_tmp_iv(aead, tmp, extralen);
570 req = esp_tmp_req(aead, iv);
571 sg = esp_req_sg(aead, req);
572
573 if (esp->inplace)
574 dsg = sg;
575 else
576 dsg = &sg[esp->nfrags];
577
578 esph = esp_output_set_extra(skb, x, esp->esph, extra);
579 esp->esph = esph;
580
581 sg_init_table(sg, esp->nfrags);
582 err = skb_to_sgvec(skb, sg,
583 (unsigned char *)esph - skb->data,
584 assoclen + ivlen + esp->clen + alen);
585 if (unlikely(err < 0))
586 goto error_free;
587
588 if (!esp->inplace) {
589 int allocsize;
590 struct page_frag *pfrag = &x->xfrag;
591
592 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
593
594 spin_lock_bh(&x->lock);
595 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
596 spin_unlock_bh(&x->lock);
597 goto error_free;
598 }
599
600 skb_shinfo(skb)->nr_frags = 1;
601
602 page = pfrag->page;
603 get_page(page);
604 /* replace page frags in skb with new page */
605 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
606 pfrag->offset = pfrag->offset + allocsize;
607 spin_unlock_bh(&x->lock);
608
609 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
610 err = skb_to_sgvec(skb, dsg,
611 (unsigned char *)esph - skb->data,
612 assoclen + ivlen + esp->clen + alen);
613 if (unlikely(err < 0))
614 goto error_free;
615 }
616
617 if ((x->props.flags & XFRM_STATE_ESN))
618 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
619 else
620 aead_request_set_callback(req, 0, esp_output_done, skb);
621
622 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
623 aead_request_set_ad(req, assoclen);
624
625 memset(iv, 0, ivlen);
626 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
627 min(ivlen, 8));
628
629 ESP_SKB_CB(skb)->tmp = tmp;
630 err = crypto_aead_encrypt(req);
631
632 switch (err) {
633 case -EINPROGRESS:
634 goto error;
635
636 case -ENOSPC:
637 err = NET_XMIT_DROP;
638 break;
639
640 case 0:
641 if ((x->props.flags & XFRM_STATE_ESN))
642 esp_output_restore_header(skb);
643 }
644
645 if (sg != dsg)
646 esp_ssg_unref(x, tmp);
647
648 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
649 err = esp_output_tail_tcp(x, skb);
650
651error_free:
652 kfree(tmp);
653error:
654 return err;
655}
656EXPORT_SYMBOL_GPL(esp_output_tail);
657
658static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
659{
660 int alen;
661 int blksize;
662 struct ip_esp_hdr *esph;
663 struct crypto_aead *aead;
664 struct esp_info esp;
665
666 esp.inplace = true;
667
668 esp.proto = *skb_mac_header(skb);
669 *skb_mac_header(skb) = IPPROTO_ESP;
670
671 /* skb is pure payload to encrypt */
672
673 aead = x->data;
674 alen = crypto_aead_authsize(aead);
675
676 esp.tfclen = 0;
677 if (x->tfcpad) {
678 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
679 u32 padto;
680
681 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
682 if (skb->len < padto)
683 esp.tfclen = padto - skb->len;
684 }
685 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
686 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
687 esp.plen = esp.clen - skb->len - esp.tfclen;
688 esp.tailen = esp.tfclen + esp.plen + alen;
689
690 esp.esph = ip_esp_hdr(skb);
691
692 esp.nfrags = esp_output_head(x, skb, &esp);
693 if (esp.nfrags < 0)
694 return esp.nfrags;
695
696 esph = esp.esph;
697 esph->spi = x->id.spi;
698
699 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
700 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
701 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
702
703 skb_push(skb, -skb_network_offset(skb));
704
705 return esp_output_tail(x, skb, &esp);
706}
707
708static inline int esp_remove_trailer(struct sk_buff *skb)
709{
710 struct xfrm_state *x = xfrm_input_state(skb);
711 struct xfrm_offload *xo = xfrm_offload(skb);
712 struct crypto_aead *aead = x->data;
713 int alen, hlen, elen;
714 int padlen, trimlen;
715 __wsum csumdiff;
716 u8 nexthdr[2];
717 int ret;
718
719 alen = crypto_aead_authsize(aead);
720 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
721 elen = skb->len - hlen;
722
723 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) {
724 ret = xo->proto;
725 goto out;
726 }
727
728 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
729 BUG();
730
731 ret = -EINVAL;
732 padlen = nexthdr[0];
733 if (padlen + 2 + alen >= elen) {
734 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
735 padlen + 2, elen - alen);
736 goto out;
737 }
738
739 trimlen = alen + padlen + 2;
740 if (skb->ip_summed == CHECKSUM_COMPLETE) {
741 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
742 skb->csum = csum_block_sub(skb->csum, csumdiff,
743 skb->len - trimlen);
744 }
745 pskb_trim(skb, skb->len - trimlen);
746
747 ret = nexthdr[1];
748
749out:
750 return ret;
751}
752
753int esp_input_done2(struct sk_buff *skb, int err)
754{
755 const struct iphdr *iph;
756 struct xfrm_state *x = xfrm_input_state(skb);
757 struct xfrm_offload *xo = xfrm_offload(skb);
758 struct crypto_aead *aead = x->data;
759 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
760 int ihl;
761
762 if (!xo || (xo && !(xo->flags & CRYPTO_DONE)))
763 kfree(ESP_SKB_CB(skb)->tmp);
764
765 if (unlikely(err))
766 goto out;
767
768 err = esp_remove_trailer(skb);
769 if (unlikely(err < 0))
770 goto out;
771
772 iph = ip_hdr(skb);
773 ihl = iph->ihl * 4;
774
775 if (x->encap) {
776 struct xfrm_encap_tmpl *encap = x->encap;
777 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl);
778 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
779 __be16 source;
780
781 switch (x->encap->encap_type) {
782 case TCP_ENCAP_ESPINTCP:
783 source = th->source;
784 break;
785 case UDP_ENCAP_ESPINUDP:
786 case UDP_ENCAP_ESPINUDP_NON_IKE:
787 source = uh->source;
788 break;
789 default:
790 WARN_ON_ONCE(1);
791 err = -EINVAL;
792 goto out;
793 }
794
795 /*
796 * 1) if the NAT-T peer's IP or port changed then
797 * advertize the change to the keying daemon.
798 * This is an inbound SA, so just compare
799 * SRC ports.
800 */
801 if (iph->saddr != x->props.saddr.a4 ||
802 source != encap->encap_sport) {
803 xfrm_address_t ipaddr;
804
805 ipaddr.a4 = iph->saddr;
806 km_new_mapping(x, &ipaddr, source);
807
808 /* XXX: perhaps add an extra
809 * policy check here, to see
810 * if we should allow or
811 * reject a packet from a
812 * different source
813 * address/port.
814 */
815 }
816
817 /*
818 * 2) ignore UDP/TCP checksums in case
819 * of NAT-T in Transport Mode, or
820 * perform other post-processing fixes
821 * as per draft-ietf-ipsec-udp-encaps-06,
822 * section 3.1.2
823 */
824 if (x->props.mode == XFRM_MODE_TRANSPORT)
825 skb->ip_summed = CHECKSUM_UNNECESSARY;
826 }
827
828 skb_pull_rcsum(skb, hlen);
829 if (x->props.mode == XFRM_MODE_TUNNEL)
830 skb_reset_transport_header(skb);
831 else
832 skb_set_transport_header(skb, -ihl);
833
834 /* RFC4303: Drop dummy packets without any error */
835 if (err == IPPROTO_NONE)
836 err = -EINVAL;
837
838out:
839 return err;
840}
841EXPORT_SYMBOL_GPL(esp_input_done2);
842
843static void esp_input_done(struct crypto_async_request *base, int err)
844{
845 struct sk_buff *skb = base->data;
846
847 xfrm_input_resume(skb, esp_input_done2(skb, err));
848}
849
850static void esp_input_restore_header(struct sk_buff *skb)
851{
852 esp_restore_header(skb, 0);
853 __skb_pull(skb, 4);
854}
855
856static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
857{
858 struct xfrm_state *x = xfrm_input_state(skb);
859 struct ip_esp_hdr *esph;
860
861 /* For ESN we move the header forward by 4 bytes to
862 * accomodate the high bits. We will move it back after
863 * decryption.
864 */
865 if ((x->props.flags & XFRM_STATE_ESN)) {
866 esph = skb_push(skb, 4);
867 *seqhi = esph->spi;
868 esph->spi = esph->seq_no;
869 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
870 }
871}
872
873static void esp_input_done_esn(struct crypto_async_request *base, int err)
874{
875 struct sk_buff *skb = base->data;
876
877 esp_input_restore_header(skb);
878 esp_input_done(base, err);
879}
880
881/*
882 * Note: detecting truncated vs. non-truncated authentication data is very
883 * expensive, so we only support truncated data, which is the recommended
884 * and common case.
885 */
886static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
887{
888 struct crypto_aead *aead = x->data;
889 struct aead_request *req;
890 struct sk_buff *trailer;
891 int ivlen = crypto_aead_ivsize(aead);
892 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
893 int nfrags;
894 int assoclen;
895 int seqhilen;
896 __be32 *seqhi;
897 void *tmp;
898 u8 *iv;
899 struct scatterlist *sg;
900 int err = -EINVAL;
901
902 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
903 goto out;
904
905 if (elen <= 0)
906 goto out;
907
908 assoclen = sizeof(struct ip_esp_hdr);
909 seqhilen = 0;
910
911 if (x->props.flags & XFRM_STATE_ESN) {
912 seqhilen += sizeof(__be32);
913 assoclen += seqhilen;
914 }
915
916 if (!skb_cloned(skb)) {
917 if (!skb_is_nonlinear(skb)) {
918 nfrags = 1;
919
920 goto skip_cow;
921 } else if (!skb_has_frag_list(skb)) {
922 nfrags = skb_shinfo(skb)->nr_frags;
923 nfrags++;
924
925 goto skip_cow;
926 }
927 }
928
929 err = skb_cow_data(skb, 0, &trailer);
930 if (err < 0)
931 goto out;
932
933 nfrags = err;
934
935skip_cow:
936 err = -ENOMEM;
937 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
938 if (!tmp)
939 goto out;
940
941 ESP_SKB_CB(skb)->tmp = tmp;
942 seqhi = esp_tmp_extra(tmp);
943 iv = esp_tmp_iv(aead, tmp, seqhilen);
944 req = esp_tmp_req(aead, iv);
945 sg = esp_req_sg(aead, req);
946
947 esp_input_set_header(skb, seqhi);
948
949 sg_init_table(sg, nfrags);
950 err = skb_to_sgvec(skb, sg, 0, skb->len);
951 if (unlikely(err < 0)) {
952 kfree(tmp);
953 goto out;
954 }
955
956 skb->ip_summed = CHECKSUM_NONE;
957
958 if ((x->props.flags & XFRM_STATE_ESN))
959 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
960 else
961 aead_request_set_callback(req, 0, esp_input_done, skb);
962
963 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
964 aead_request_set_ad(req, assoclen);
965
966 err = crypto_aead_decrypt(req);
967 if (err == -EINPROGRESS)
968 goto out;
969
970 if ((x->props.flags & XFRM_STATE_ESN))
971 esp_input_restore_header(skb);
972
973 err = esp_input_done2(skb, err);
974
975out:
976 return err;
977}
978
979static int esp4_err(struct sk_buff *skb, u32 info)
980{
981 struct net *net = dev_net(skb->dev);
982 const struct iphdr *iph = (const struct iphdr *)skb->data;
983 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
984 struct xfrm_state *x;
985
986 switch (icmp_hdr(skb)->type) {
987 case ICMP_DEST_UNREACH:
988 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
989 return 0;
990 case ICMP_REDIRECT:
991 break;
992 default:
993 return 0;
994 }
995
996 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
997 esph->spi, IPPROTO_ESP, AF_INET);
998 if (!x)
999 return 0;
1000
1001 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
1002 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP);
1003 else
1004 ipv4_redirect(skb, net, 0, IPPROTO_ESP);
1005 xfrm_state_put(x);
1006
1007 return 0;
1008}
1009
1010static void esp_destroy(struct xfrm_state *x)
1011{
1012 struct crypto_aead *aead = x->data;
1013
1014 if (!aead)
1015 return;
1016
1017 crypto_free_aead(aead);
1018}
1019
1020static int esp_init_aead(struct xfrm_state *x)
1021{
1022 char aead_name[CRYPTO_MAX_ALG_NAME];
1023 struct crypto_aead *aead;
1024 int err;
1025
1026 err = -ENAMETOOLONG;
1027 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1028 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
1029 goto error;
1030
1031 aead = crypto_alloc_aead(aead_name, 0, 0);
1032 err = PTR_ERR(aead);
1033 if (IS_ERR(aead))
1034 goto error;
1035
1036 x->data = aead;
1037
1038 err = crypto_aead_setkey(aead, x->aead->alg_key,
1039 (x->aead->alg_key_len + 7) / 8);
1040 if (err)
1041 goto error;
1042
1043 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1044 if (err)
1045 goto error;
1046
1047error:
1048 return err;
1049}
1050
1051static int esp_init_authenc(struct xfrm_state *x)
1052{
1053 struct crypto_aead *aead;
1054 struct crypto_authenc_key_param *param;
1055 struct rtattr *rta;
1056 char *key;
1057 char *p;
1058 char authenc_name[CRYPTO_MAX_ALG_NAME];
1059 unsigned int keylen;
1060 int err;
1061
1062 err = -EINVAL;
1063 if (!x->ealg)
1064 goto error;
1065
1066 err = -ENAMETOOLONG;
1067
1068 if ((x->props.flags & XFRM_STATE_ESN)) {
1069 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1070 "%s%sauthencesn(%s,%s)%s",
1071 x->geniv ?: "", x->geniv ? "(" : "",
1072 x->aalg ? x->aalg->alg_name : "digest_null",
1073 x->ealg->alg_name,
1074 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
1075 goto error;
1076 } else {
1077 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1078 "%s%sauthenc(%s,%s)%s",
1079 x->geniv ?: "", x->geniv ? "(" : "",
1080 x->aalg ? x->aalg->alg_name : "digest_null",
1081 x->ealg->alg_name,
1082 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
1083 goto error;
1084 }
1085
1086 aead = crypto_alloc_aead(authenc_name, 0, 0);
1087 err = PTR_ERR(aead);
1088 if (IS_ERR(aead))
1089 goto error;
1090
1091 x->data = aead;
1092
1093 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1094 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1095 err = -ENOMEM;
1096 key = kmalloc(keylen, GFP_KERNEL);
1097 if (!key)
1098 goto error;
1099
1100 p = key;
1101 rta = (void *)p;
1102 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1103 rta->rta_len = RTA_LENGTH(sizeof(*param));
1104 param = RTA_DATA(rta);
1105 p += RTA_SPACE(sizeof(*param));
1106
1107 if (x->aalg) {
1108 struct xfrm_algo_desc *aalg_desc;
1109
1110 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1111 p += (x->aalg->alg_key_len + 7) / 8;
1112
1113 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1114 BUG_ON(!aalg_desc);
1115
1116 err = -EINVAL;
1117 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1118 crypto_aead_authsize(aead)) {
1119 pr_info("ESP: %s digestsize %u != %hu\n",
1120 x->aalg->alg_name,
1121 crypto_aead_authsize(aead),
1122 aalg_desc->uinfo.auth.icv_fullbits / 8);
1123 goto free_key;
1124 }
1125
1126 err = crypto_aead_setauthsize(
1127 aead, x->aalg->alg_trunc_len / 8);
1128 if (err)
1129 goto free_key;
1130 }
1131
1132 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1133 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1134
1135 err = crypto_aead_setkey(aead, key, keylen);
1136
1137free_key:
1138 kfree(key);
1139
1140error:
1141 return err;
1142}
1143
1144static int esp_init_state(struct xfrm_state *x)
1145{
1146 struct crypto_aead *aead;
1147 u32 align;
1148 int err;
1149
1150 x->data = NULL;
1151
1152 if (x->aead)
1153 err = esp_init_aead(x);
1154 else
1155 err = esp_init_authenc(x);
1156
1157 if (err)
1158 goto error;
1159
1160 aead = x->data;
1161
1162 x->props.header_len = sizeof(struct ip_esp_hdr) +
1163 crypto_aead_ivsize(aead);
1164 if (x->props.mode == XFRM_MODE_TUNNEL)
1165 x->props.header_len += sizeof(struct iphdr);
1166 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
1167 x->props.header_len += IPV4_BEET_PHMAXLEN;
1168 if (x->encap) {
1169 struct xfrm_encap_tmpl *encap = x->encap;
1170
1171 switch (encap->encap_type) {
1172 default:
1173 err = -EINVAL;
1174 goto error;
1175 case UDP_ENCAP_ESPINUDP:
1176 x->props.header_len += sizeof(struct udphdr);
1177 break;
1178 case UDP_ENCAP_ESPINUDP_NON_IKE:
1179 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
1180 break;
1181#ifdef CONFIG_INET_ESPINTCP
1182 case TCP_ENCAP_ESPINTCP:
1183 /* only the length field, TCP encap is done by
1184 * the socket
1185 */
1186 x->props.header_len += 2;
1187 break;
1188#endif
1189 }
1190 }
1191
1192 align = ALIGN(crypto_aead_blocksize(aead), 4);
1193 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1194
1195error:
1196 return err;
1197}
1198
1199static int esp4_rcv_cb(struct sk_buff *skb, int err)
1200{
1201 return 0;
1202}
1203
1204static const struct xfrm_type esp_type =
1205{
1206 .description = "ESP4",
1207 .owner = THIS_MODULE,
1208 .proto = IPPROTO_ESP,
1209 .flags = XFRM_TYPE_REPLAY_PROT,
1210 .init_state = esp_init_state,
1211 .destructor = esp_destroy,
1212 .input = esp_input,
1213 .output = esp_output,
1214};
1215
1216static struct xfrm4_protocol esp4_protocol = {
1217 .handler = xfrm4_rcv,
1218 .input_handler = xfrm_input,
1219 .cb_handler = esp4_rcv_cb,
1220 .err_handler = esp4_err,
1221 .priority = 0,
1222};
1223
1224static int __init esp4_init(void)
1225{
1226 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1227 pr_info("%s: can't add xfrm type\n", __func__);
1228 return -EAGAIN;
1229 }
1230 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1231 pr_info("%s: can't add protocol\n", __func__);
1232 xfrm_unregister_type(&esp_type, AF_INET);
1233 return -EAGAIN;
1234 }
1235 return 0;
1236}
1237
1238static void __exit esp4_fini(void)
1239{
1240 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1241 pr_info("%s: can't remove protocol\n", __func__);
1242 xfrm_unregister_type(&esp_type, AF_INET);
1243}
1244
1245module_init(esp4_init);
1246module_exit(esp4_fini);
1247MODULE_LICENSE("GPL");
1248MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);