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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, struct sk_buff *skb)
99{
100 struct crypto_aead *aead = x->data;
101 int extralen = 0;
102 u8 *iv;
103 struct aead_request *req;
104 struct scatterlist *sg;
105
106 if (x->props.flags & XFRM_STATE_ESN)
107 extralen += sizeof(struct esp_output_extra);
108
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 skb_page_unref(skb, sg_page(sg), false);
118}
119
120#ifdef CONFIG_INET_ESPINTCP
121struct esp_tcp_sk {
122 struct sock *sk;
123 struct rcu_head rcu;
124};
125
126static void esp_free_tcp_sk(struct rcu_head *head)
127{
128 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu);
129
130 sock_put(esk->sk);
131 kfree(esk);
132}
133
134static struct sock *esp_find_tcp_sk(struct xfrm_state *x)
135{
136 struct xfrm_encap_tmpl *encap = x->encap;
137 struct net *net = xs_net(x);
138 struct esp_tcp_sk *esk;
139 __be16 sport, dport;
140 struct sock *nsk;
141 struct sock *sk;
142
143 sk = rcu_dereference(x->encap_sk);
144 if (sk && sk->sk_state == TCP_ESTABLISHED)
145 return sk;
146
147 spin_lock_bh(&x->lock);
148 sport = encap->encap_sport;
149 dport = encap->encap_dport;
150 nsk = rcu_dereference_protected(x->encap_sk,
151 lockdep_is_held(&x->lock));
152 if (sk && sk == nsk) {
153 esk = kmalloc(sizeof(*esk), GFP_ATOMIC);
154 if (!esk) {
155 spin_unlock_bh(&x->lock);
156 return ERR_PTR(-ENOMEM);
157 }
158 RCU_INIT_POINTER(x->encap_sk, NULL);
159 esk->sk = sk;
160 call_rcu(&esk->rcu, esp_free_tcp_sk);
161 }
162 spin_unlock_bh(&x->lock);
163
164 sk = inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, x->id.daddr.a4,
165 dport, x->props.saddr.a4, sport, 0);
166 if (!sk)
167 return ERR_PTR(-ENOENT);
168
169 if (!tcp_is_ulp_esp(sk)) {
170 sock_put(sk);
171 return ERR_PTR(-EINVAL);
172 }
173
174 spin_lock_bh(&x->lock);
175 nsk = rcu_dereference_protected(x->encap_sk,
176 lockdep_is_held(&x->lock));
177 if (encap->encap_sport != sport ||
178 encap->encap_dport != dport) {
179 sock_put(sk);
180 sk = nsk ?: ERR_PTR(-EREMCHG);
181 } else if (sk == nsk) {
182 sock_put(sk);
183 } else {
184 rcu_assign_pointer(x->encap_sk, sk);
185 }
186 spin_unlock_bh(&x->lock);
187
188 return sk;
189}
190
191static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
192{
193 struct sock *sk;
194 int err;
195
196 rcu_read_lock();
197
198 sk = esp_find_tcp_sk(x);
199 err = PTR_ERR_OR_ZERO(sk);
200 if (err)
201 goto out;
202
203 bh_lock_sock(sk);
204 if (sock_owned_by_user(sk))
205 err = espintcp_queue_out(sk, skb);
206 else
207 err = espintcp_push_skb(sk, skb);
208 bh_unlock_sock(sk);
209
210out:
211 rcu_read_unlock();
212 return err;
213}
214
215static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
216 struct sk_buff *skb)
217{
218 struct dst_entry *dst = skb_dst(skb);
219 struct xfrm_state *x = dst->xfrm;
220
221 return esp_output_tcp_finish(x, skb);
222}
223
224static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
225{
226 int err;
227
228 local_bh_disable();
229 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
230 local_bh_enable();
231
232 /* EINPROGRESS just happens to do the right thing. It
233 * actually means that the skb has been consumed and
234 * isn't coming back.
235 */
236 return err ?: -EINPROGRESS;
237}
238#else
239static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
240{
241 kfree_skb(skb);
242
243 return -EOPNOTSUPP;
244}
245#endif
246
247static void esp_output_done(void *data, int err)
248{
249 struct sk_buff *skb = data;
250 struct xfrm_offload *xo = xfrm_offload(skb);
251 void *tmp;
252 struct xfrm_state *x;
253
254 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
255 struct sec_path *sp = skb_sec_path(skb);
256
257 x = sp->xvec[sp->len - 1];
258 } else {
259 x = skb_dst(skb)->xfrm;
260 }
261
262 tmp = ESP_SKB_CB(skb)->tmp;
263 esp_ssg_unref(x, tmp, skb);
264 kfree(tmp);
265
266 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
267 if (err) {
268 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
269 kfree_skb(skb);
270 return;
271 }
272
273 skb_push(skb, skb->data - skb_mac_header(skb));
274 secpath_reset(skb);
275 xfrm_dev_resume(skb);
276 } else {
277 if (!err &&
278 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
279 esp_output_tail_tcp(x, skb);
280 else
281 xfrm_output_resume(skb->sk, skb, err);
282 }
283}
284
285/* Move ESP header back into place. */
286static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
287{
288 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
289 void *tmp = ESP_SKB_CB(skb)->tmp;
290 __be32 *seqhi = esp_tmp_extra(tmp);
291
292 esph->seq_no = esph->spi;
293 esph->spi = *seqhi;
294}
295
296static void esp_output_restore_header(struct sk_buff *skb)
297{
298 void *tmp = ESP_SKB_CB(skb)->tmp;
299 struct esp_output_extra *extra = esp_tmp_extra(tmp);
300
301 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
302 sizeof(__be32));
303}
304
305static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
306 struct xfrm_state *x,
307 struct ip_esp_hdr *esph,
308 struct esp_output_extra *extra)
309{
310 /* For ESN we move the header forward by 4 bytes to
311 * accommodate the high bits. We will move it back after
312 * encryption.
313 */
314 if ((x->props.flags & XFRM_STATE_ESN)) {
315 __u32 seqhi;
316 struct xfrm_offload *xo = xfrm_offload(skb);
317
318 if (xo)
319 seqhi = xo->seq.hi;
320 else
321 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
322
323 extra->esphoff = (unsigned char *)esph -
324 skb_transport_header(skb);
325 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
326 extra->seqhi = esph->spi;
327 esph->seq_no = htonl(seqhi);
328 }
329
330 esph->spi = x->id.spi;
331
332 return esph;
333}
334
335static void esp_output_done_esn(void *data, int err)
336{
337 struct sk_buff *skb = data;
338
339 esp_output_restore_header(skb);
340 esp_output_done(data, err);
341}
342
343static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb,
344 int encap_type,
345 struct esp_info *esp,
346 __be16 sport,
347 __be16 dport)
348{
349 struct udphdr *uh;
350 __be32 *udpdata32;
351 unsigned int len;
352
353 len = skb->len + esp->tailen - skb_transport_offset(skb);
354 if (len + sizeof(struct iphdr) > IP_MAX_MTU)
355 return ERR_PTR(-EMSGSIZE);
356
357 uh = (struct udphdr *)esp->esph;
358 uh->source = sport;
359 uh->dest = dport;
360 uh->len = htons(len);
361 uh->check = 0;
362
363 *skb_mac_header(skb) = IPPROTO_UDP;
364
365 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
366 udpdata32 = (__be32 *)(uh + 1);
367 udpdata32[0] = udpdata32[1] = 0;
368 return (struct ip_esp_hdr *)(udpdata32 + 2);
369 }
370
371 return (struct ip_esp_hdr *)(uh + 1);
372}
373
374#ifdef CONFIG_INET_ESPINTCP
375static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
376 struct sk_buff *skb,
377 struct esp_info *esp)
378{
379 __be16 *lenp = (void *)esp->esph;
380 struct ip_esp_hdr *esph;
381 unsigned int len;
382 struct sock *sk;
383
384 len = skb->len + esp->tailen - skb_transport_offset(skb);
385 if (len > IP_MAX_MTU)
386 return ERR_PTR(-EMSGSIZE);
387
388 rcu_read_lock();
389 sk = esp_find_tcp_sk(x);
390 rcu_read_unlock();
391
392 if (IS_ERR(sk))
393 return ERR_CAST(sk);
394
395 *lenp = htons(len);
396 esph = (struct ip_esp_hdr *)(lenp + 1);
397
398 return esph;
399}
400#else
401static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
402 struct sk_buff *skb,
403 struct esp_info *esp)
404{
405 return ERR_PTR(-EOPNOTSUPP);
406}
407#endif
408
409static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb,
410 struct esp_info *esp)
411{
412 struct xfrm_encap_tmpl *encap = x->encap;
413 struct ip_esp_hdr *esph;
414 __be16 sport, dport;
415 int encap_type;
416
417 spin_lock_bh(&x->lock);
418 sport = encap->encap_sport;
419 dport = encap->encap_dport;
420 encap_type = encap->encap_type;
421 spin_unlock_bh(&x->lock);
422
423 switch (encap_type) {
424 default:
425 case UDP_ENCAP_ESPINUDP:
426 case UDP_ENCAP_ESPINUDP_NON_IKE:
427 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport);
428 break;
429 case TCP_ENCAP_ESPINTCP:
430 esph = esp_output_tcp_encap(x, skb, esp);
431 break;
432 }
433
434 if (IS_ERR(esph))
435 return PTR_ERR(esph);
436
437 esp->esph = esph;
438
439 return 0;
440}
441
442int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
443{
444 u8 *tail;
445 int nfrags;
446 int esph_offset;
447 struct page *page;
448 struct sk_buff *trailer;
449 int tailen = esp->tailen;
450
451 /* this is non-NULL only with TCP/UDP Encapsulation */
452 if (x->encap) {
453 int err = esp_output_encap(x, skb, esp);
454
455 if (err < 0)
456 return err;
457 }
458
459 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
460 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
461 goto cow;
462
463 if (!skb_cloned(skb)) {
464 if (tailen <= skb_tailroom(skb)) {
465 nfrags = 1;
466 trailer = skb;
467 tail = skb_tail_pointer(trailer);
468
469 goto skip_cow;
470 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
471 && !skb_has_frag_list(skb)) {
472 int allocsize;
473 struct sock *sk = skb->sk;
474 struct page_frag *pfrag = &x->xfrag;
475
476 esp->inplace = false;
477
478 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
479
480 spin_lock_bh(&x->lock);
481
482 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
483 spin_unlock_bh(&x->lock);
484 goto cow;
485 }
486
487 page = pfrag->page;
488 get_page(page);
489
490 tail = page_address(page) + pfrag->offset;
491
492 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
493
494 nfrags = skb_shinfo(skb)->nr_frags;
495
496 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
497 tailen);
498 skb_shinfo(skb)->nr_frags = ++nfrags;
499
500 pfrag->offset = pfrag->offset + allocsize;
501
502 spin_unlock_bh(&x->lock);
503
504 nfrags++;
505
506 skb_len_add(skb, tailen);
507 if (sk && sk_fullsock(sk))
508 refcount_add(tailen, &sk->sk_wmem_alloc);
509
510 goto out;
511 }
512 }
513
514cow:
515 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
516
517 nfrags = skb_cow_data(skb, tailen, &trailer);
518 if (nfrags < 0)
519 goto out;
520 tail = skb_tail_pointer(trailer);
521 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
522
523skip_cow:
524 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
525 pskb_put(skb, trailer, tailen);
526
527out:
528 return nfrags;
529}
530EXPORT_SYMBOL_GPL(esp_output_head);
531
532int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
533{
534 u8 *iv;
535 int alen;
536 void *tmp;
537 int ivlen;
538 int assoclen;
539 int extralen;
540 struct page *page;
541 struct ip_esp_hdr *esph;
542 struct crypto_aead *aead;
543 struct aead_request *req;
544 struct scatterlist *sg, *dsg;
545 struct esp_output_extra *extra;
546 int err = -ENOMEM;
547
548 assoclen = sizeof(struct ip_esp_hdr);
549 extralen = 0;
550
551 if (x->props.flags & XFRM_STATE_ESN) {
552 extralen += sizeof(*extra);
553 assoclen += sizeof(__be32);
554 }
555
556 aead = x->data;
557 alen = crypto_aead_authsize(aead);
558 ivlen = crypto_aead_ivsize(aead);
559
560 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
561 if (!tmp)
562 goto error;
563
564 extra = esp_tmp_extra(tmp);
565 iv = esp_tmp_iv(aead, tmp, extralen);
566 req = esp_tmp_req(aead, iv);
567 sg = esp_req_sg(aead, req);
568
569 if (esp->inplace)
570 dsg = sg;
571 else
572 dsg = &sg[esp->nfrags];
573
574 esph = esp_output_set_extra(skb, x, esp->esph, extra);
575 esp->esph = esph;
576
577 sg_init_table(sg, esp->nfrags);
578 err = skb_to_sgvec(skb, sg,
579 (unsigned char *)esph - skb->data,
580 assoclen + ivlen + esp->clen + alen);
581 if (unlikely(err < 0))
582 goto error_free;
583
584 if (!esp->inplace) {
585 int allocsize;
586 struct page_frag *pfrag = &x->xfrag;
587
588 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
589
590 spin_lock_bh(&x->lock);
591 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
592 spin_unlock_bh(&x->lock);
593 goto error_free;
594 }
595
596 skb_shinfo(skb)->nr_frags = 1;
597
598 page = pfrag->page;
599 get_page(page);
600 /* replace page frags in skb with new page */
601 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
602 pfrag->offset = pfrag->offset + allocsize;
603 spin_unlock_bh(&x->lock);
604
605 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
606 err = skb_to_sgvec(skb, dsg,
607 (unsigned char *)esph - skb->data,
608 assoclen + ivlen + esp->clen + alen);
609 if (unlikely(err < 0))
610 goto error_free;
611 }
612
613 if ((x->props.flags & XFRM_STATE_ESN))
614 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
615 else
616 aead_request_set_callback(req, 0, esp_output_done, skb);
617
618 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
619 aead_request_set_ad(req, assoclen);
620
621 memset(iv, 0, ivlen);
622 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
623 min(ivlen, 8));
624
625 ESP_SKB_CB(skb)->tmp = tmp;
626 err = crypto_aead_encrypt(req);
627
628 switch (err) {
629 case -EINPROGRESS:
630 goto error;
631
632 case -ENOSPC:
633 err = NET_XMIT_DROP;
634 break;
635
636 case 0:
637 if ((x->props.flags & XFRM_STATE_ESN))
638 esp_output_restore_header(skb);
639 }
640
641 if (sg != dsg)
642 esp_ssg_unref(x, tmp, skb);
643
644 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
645 err = esp_output_tail_tcp(x, skb);
646
647error_free:
648 kfree(tmp);
649error:
650 return err;
651}
652EXPORT_SYMBOL_GPL(esp_output_tail);
653
654static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
655{
656 int alen;
657 int blksize;
658 struct ip_esp_hdr *esph;
659 struct crypto_aead *aead;
660 struct esp_info esp;
661
662 esp.inplace = true;
663
664 esp.proto = *skb_mac_header(skb);
665 *skb_mac_header(skb) = IPPROTO_ESP;
666
667 /* skb is pure payload to encrypt */
668
669 aead = x->data;
670 alen = crypto_aead_authsize(aead);
671
672 esp.tfclen = 0;
673 if (x->tfcpad) {
674 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
675 u32 padto;
676
677 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
678 if (skb->len < padto)
679 esp.tfclen = padto - skb->len;
680 }
681 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
682 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
683 esp.plen = esp.clen - skb->len - esp.tfclen;
684 esp.tailen = esp.tfclen + esp.plen + alen;
685
686 esp.esph = ip_esp_hdr(skb);
687
688 esp.nfrags = esp_output_head(x, skb, &esp);
689 if (esp.nfrags < 0)
690 return esp.nfrags;
691
692 esph = esp.esph;
693 esph->spi = x->id.spi;
694
695 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
696 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
697 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
698
699 skb_push(skb, -skb_network_offset(skb));
700
701 return esp_output_tail(x, skb, &esp);
702}
703
704static inline int esp_remove_trailer(struct sk_buff *skb)
705{
706 struct xfrm_state *x = xfrm_input_state(skb);
707 struct crypto_aead *aead = x->data;
708 int alen, hlen, elen;
709 int padlen, trimlen;
710 __wsum csumdiff;
711 u8 nexthdr[2];
712 int ret;
713
714 alen = crypto_aead_authsize(aead);
715 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
716 elen = skb->len - hlen;
717
718 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
719 BUG();
720
721 ret = -EINVAL;
722 padlen = nexthdr[0];
723 if (padlen + 2 + alen >= elen) {
724 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
725 padlen + 2, elen - alen);
726 goto out;
727 }
728
729 trimlen = alen + padlen + 2;
730 if (skb->ip_summed == CHECKSUM_COMPLETE) {
731 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
732 skb->csum = csum_block_sub(skb->csum, csumdiff,
733 skb->len - trimlen);
734 }
735 ret = pskb_trim(skb, skb->len - trimlen);
736 if (unlikely(ret))
737 return ret;
738
739 ret = nexthdr[1];
740
741out:
742 return ret;
743}
744
745int esp_input_done2(struct sk_buff *skb, int err)
746{
747 const struct iphdr *iph;
748 struct xfrm_state *x = xfrm_input_state(skb);
749 struct xfrm_offload *xo = xfrm_offload(skb);
750 struct crypto_aead *aead = x->data;
751 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
752 int ihl;
753
754 if (!xo || !(xo->flags & CRYPTO_DONE))
755 kfree(ESP_SKB_CB(skb)->tmp);
756
757 if (unlikely(err))
758 goto out;
759
760 err = esp_remove_trailer(skb);
761 if (unlikely(err < 0))
762 goto out;
763
764 iph = ip_hdr(skb);
765 ihl = iph->ihl * 4;
766
767 if (x->encap) {
768 struct xfrm_encap_tmpl *encap = x->encap;
769 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl);
770 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
771 __be16 source;
772
773 switch (x->encap->encap_type) {
774 case TCP_ENCAP_ESPINTCP:
775 source = th->source;
776 break;
777 case UDP_ENCAP_ESPINUDP:
778 case UDP_ENCAP_ESPINUDP_NON_IKE:
779 source = uh->source;
780 break;
781 default:
782 WARN_ON_ONCE(1);
783 err = -EINVAL;
784 goto out;
785 }
786
787 /*
788 * 1) if the NAT-T peer's IP or port changed then
789 * advertise the change to the keying daemon.
790 * This is an inbound SA, so just compare
791 * SRC ports.
792 */
793 if (iph->saddr != x->props.saddr.a4 ||
794 source != encap->encap_sport) {
795 xfrm_address_t ipaddr;
796
797 ipaddr.a4 = iph->saddr;
798 km_new_mapping(x, &ipaddr, source);
799
800 /* XXX: perhaps add an extra
801 * policy check here, to see
802 * if we should allow or
803 * reject a packet from a
804 * different source
805 * address/port.
806 */
807 }
808
809 /*
810 * 2) ignore UDP/TCP checksums in case
811 * of NAT-T in Transport Mode, or
812 * perform other post-processing fixes
813 * as per draft-ietf-ipsec-udp-encaps-06,
814 * section 3.1.2
815 */
816 if (x->props.mode == XFRM_MODE_TRANSPORT)
817 skb->ip_summed = CHECKSUM_UNNECESSARY;
818 }
819
820 skb_pull_rcsum(skb, hlen);
821 if (x->props.mode == XFRM_MODE_TUNNEL)
822 skb_reset_transport_header(skb);
823 else
824 skb_set_transport_header(skb, -ihl);
825
826 /* RFC4303: Drop dummy packets without any error */
827 if (err == IPPROTO_NONE)
828 err = -EINVAL;
829
830out:
831 return err;
832}
833EXPORT_SYMBOL_GPL(esp_input_done2);
834
835static void esp_input_done(void *data, int err)
836{
837 struct sk_buff *skb = data;
838
839 xfrm_input_resume(skb, esp_input_done2(skb, err));
840}
841
842static void esp_input_restore_header(struct sk_buff *skb)
843{
844 esp_restore_header(skb, 0);
845 __skb_pull(skb, 4);
846}
847
848static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
849{
850 struct xfrm_state *x = xfrm_input_state(skb);
851 struct ip_esp_hdr *esph;
852
853 /* For ESN we move the header forward by 4 bytes to
854 * accommodate the high bits. We will move it back after
855 * decryption.
856 */
857 if ((x->props.flags & XFRM_STATE_ESN)) {
858 esph = skb_push(skb, 4);
859 *seqhi = esph->spi;
860 esph->spi = esph->seq_no;
861 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
862 }
863}
864
865static void esp_input_done_esn(void *data, int err)
866{
867 struct sk_buff *skb = data;
868
869 esp_input_restore_header(skb);
870 esp_input_done(data, err);
871}
872
873/*
874 * Note: detecting truncated vs. non-truncated authentication data is very
875 * expensive, so we only support truncated data, which is the recommended
876 * and common case.
877 */
878static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
879{
880 struct crypto_aead *aead = x->data;
881 struct aead_request *req;
882 struct sk_buff *trailer;
883 int ivlen = crypto_aead_ivsize(aead);
884 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
885 int nfrags;
886 int assoclen;
887 int seqhilen;
888 __be32 *seqhi;
889 void *tmp;
890 u8 *iv;
891 struct scatterlist *sg;
892 int err = -EINVAL;
893
894 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
895 goto out;
896
897 if (elen <= 0)
898 goto out;
899
900 assoclen = sizeof(struct ip_esp_hdr);
901 seqhilen = 0;
902
903 if (x->props.flags & XFRM_STATE_ESN) {
904 seqhilen += sizeof(__be32);
905 assoclen += seqhilen;
906 }
907
908 if (!skb_cloned(skb)) {
909 if (!skb_is_nonlinear(skb)) {
910 nfrags = 1;
911
912 goto skip_cow;
913 } else if (!skb_has_frag_list(skb)) {
914 nfrags = skb_shinfo(skb)->nr_frags;
915 nfrags++;
916
917 goto skip_cow;
918 }
919 }
920
921 err = skb_cow_data(skb, 0, &trailer);
922 if (err < 0)
923 goto out;
924
925 nfrags = err;
926
927skip_cow:
928 err = -ENOMEM;
929 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
930 if (!tmp)
931 goto out;
932
933 ESP_SKB_CB(skb)->tmp = tmp;
934 seqhi = esp_tmp_extra(tmp);
935 iv = esp_tmp_iv(aead, tmp, seqhilen);
936 req = esp_tmp_req(aead, iv);
937 sg = esp_req_sg(aead, req);
938
939 esp_input_set_header(skb, seqhi);
940
941 sg_init_table(sg, nfrags);
942 err = skb_to_sgvec(skb, sg, 0, skb->len);
943 if (unlikely(err < 0)) {
944 kfree(tmp);
945 goto out;
946 }
947
948 skb->ip_summed = CHECKSUM_NONE;
949
950 if ((x->props.flags & XFRM_STATE_ESN))
951 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
952 else
953 aead_request_set_callback(req, 0, esp_input_done, skb);
954
955 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
956 aead_request_set_ad(req, assoclen);
957
958 err = crypto_aead_decrypt(req);
959 if (err == -EINPROGRESS)
960 goto out;
961
962 if ((x->props.flags & XFRM_STATE_ESN))
963 esp_input_restore_header(skb);
964
965 err = esp_input_done2(skb, err);
966
967out:
968 return err;
969}
970
971static int esp4_err(struct sk_buff *skb, u32 info)
972{
973 struct net *net = dev_net(skb->dev);
974 const struct iphdr *iph = (const struct iphdr *)skb->data;
975 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
976 struct xfrm_state *x;
977
978 switch (icmp_hdr(skb)->type) {
979 case ICMP_DEST_UNREACH:
980 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
981 return 0;
982 break;
983 case ICMP_REDIRECT:
984 break;
985 default:
986 return 0;
987 }
988
989 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
990 esph->spi, IPPROTO_ESP, AF_INET);
991 if (!x)
992 return 0;
993
994 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
995 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP);
996 else
997 ipv4_redirect(skb, net, 0, IPPROTO_ESP);
998 xfrm_state_put(x);
999
1000 return 0;
1001}
1002
1003static void esp_destroy(struct xfrm_state *x)
1004{
1005 struct crypto_aead *aead = x->data;
1006
1007 if (!aead)
1008 return;
1009
1010 crypto_free_aead(aead);
1011}
1012
1013static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
1014{
1015 char aead_name[CRYPTO_MAX_ALG_NAME];
1016 struct crypto_aead *aead;
1017 int err;
1018
1019 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1020 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
1021 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1022 return -ENAMETOOLONG;
1023 }
1024
1025 aead = crypto_alloc_aead(aead_name, 0, 0);
1026 err = PTR_ERR(aead);
1027 if (IS_ERR(aead))
1028 goto error;
1029
1030 x->data = aead;
1031
1032 err = crypto_aead_setkey(aead, x->aead->alg_key,
1033 (x->aead->alg_key_len + 7) / 8);
1034 if (err)
1035 goto error;
1036
1037 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1038 if (err)
1039 goto error;
1040
1041 return 0;
1042
1043error:
1044 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1045 return err;
1046}
1047
1048static int esp_init_authenc(struct xfrm_state *x,
1049 struct netlink_ext_ack *extack)
1050{
1051 struct crypto_aead *aead;
1052 struct crypto_authenc_key_param *param;
1053 struct rtattr *rta;
1054 char *key;
1055 char *p;
1056 char authenc_name[CRYPTO_MAX_ALG_NAME];
1057 unsigned int keylen;
1058 int err;
1059
1060 err = -ENAMETOOLONG;
1061
1062 if ((x->props.flags & XFRM_STATE_ESN)) {
1063 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1064 "%s%sauthencesn(%s,%s)%s",
1065 x->geniv ?: "", x->geniv ? "(" : "",
1066 x->aalg ? x->aalg->alg_name : "digest_null",
1067 x->ealg->alg_name,
1068 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1069 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1070 goto error;
1071 }
1072 } else {
1073 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1074 "%s%sauthenc(%s,%s)%s",
1075 x->geniv ?: "", x->geniv ? "(" : "",
1076 x->aalg ? x->aalg->alg_name : "digest_null",
1077 x->ealg->alg_name,
1078 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1079 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1080 goto error;
1081 }
1082 }
1083
1084 aead = crypto_alloc_aead(authenc_name, 0, 0);
1085 err = PTR_ERR(aead);
1086 if (IS_ERR(aead)) {
1087 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1088 goto error;
1089 }
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 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1120 goto free_key;
1121 }
1122
1123 err = crypto_aead_setauthsize(
1124 aead, x->aalg->alg_trunc_len / 8);
1125 if (err) {
1126 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1127 goto free_key;
1128 }
1129 }
1130
1131 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1132 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1133
1134 err = crypto_aead_setkey(aead, key, keylen);
1135
1136free_key:
1137 kfree_sensitive(key);
1138
1139error:
1140 return err;
1141}
1142
1143static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
1144{
1145 struct crypto_aead *aead;
1146 u32 align;
1147 int err;
1148
1149 x->data = NULL;
1150
1151 if (x->aead) {
1152 err = esp_init_aead(x, extack);
1153 } else if (x->ealg) {
1154 err = esp_init_authenc(x, extack);
1155 } else {
1156 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided");
1157 err = -EINVAL;
1158 }
1159
1160 if (err)
1161 goto error;
1162
1163 aead = x->data;
1164
1165 x->props.header_len = sizeof(struct ip_esp_hdr) +
1166 crypto_aead_ivsize(aead);
1167 if (x->props.mode == XFRM_MODE_TUNNEL)
1168 x->props.header_len += sizeof(struct iphdr);
1169 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
1170 x->props.header_len += IPV4_BEET_PHMAXLEN;
1171 if (x->encap) {
1172 struct xfrm_encap_tmpl *encap = x->encap;
1173
1174 switch (encap->encap_type) {
1175 default:
1176 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP");
1177 err = -EINVAL;
1178 goto error;
1179 case UDP_ENCAP_ESPINUDP:
1180 x->props.header_len += sizeof(struct udphdr);
1181 break;
1182 case UDP_ENCAP_ESPINUDP_NON_IKE:
1183 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
1184 break;
1185#ifdef CONFIG_INET_ESPINTCP
1186 case TCP_ENCAP_ESPINTCP:
1187 /* only the length field, TCP encap is done by
1188 * the socket
1189 */
1190 x->props.header_len += 2;
1191 break;
1192#endif
1193 }
1194 }
1195
1196 align = ALIGN(crypto_aead_blocksize(aead), 4);
1197 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1198
1199error:
1200 return err;
1201}
1202
1203static int esp4_rcv_cb(struct sk_buff *skb, int err)
1204{
1205 return 0;
1206}
1207
1208static const struct xfrm_type esp_type =
1209{
1210 .owner = THIS_MODULE,
1211 .proto = IPPROTO_ESP,
1212 .flags = XFRM_TYPE_REPLAY_PROT,
1213 .init_state = esp_init_state,
1214 .destructor = esp_destroy,
1215 .input = esp_input,
1216 .output = esp_output,
1217};
1218
1219static struct xfrm4_protocol esp4_protocol = {
1220 .handler = xfrm4_rcv,
1221 .input_handler = xfrm_input,
1222 .cb_handler = esp4_rcv_cb,
1223 .err_handler = esp4_err,
1224 .priority = 0,
1225};
1226
1227static int __init esp4_init(void)
1228{
1229 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1230 pr_info("%s: can't add xfrm type\n", __func__);
1231 return -EAGAIN;
1232 }
1233 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1234 pr_info("%s: can't add protocol\n", __func__);
1235 xfrm_unregister_type(&esp_type, AF_INET);
1236 return -EAGAIN;
1237 }
1238 return 0;
1239}
1240
1241static void __exit esp4_fini(void)
1242{
1243 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1244 pr_info("%s: can't remove protocol\n", __func__);
1245 xfrm_unregister_type(&esp_type, AF_INET);
1246}
1247
1248module_init(esp4_init);
1249module_exit(esp4_fini);
1250MODULE_DESCRIPTION("IPv4 ESP transformation library");
1251MODULE_LICENSE("GPL");
1252MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);