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
21#include <linux/highmem.h>
22
23struct esp_skb_cb {
24 struct xfrm_skb_cb xfrm;
25 void *tmp;
26};
27
28struct esp_output_extra {
29 __be32 seqhi;
30 u32 esphoff;
31};
32
33#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
34
35static u32 esp4_get_mtu(struct xfrm_state *x, int mtu);
36
37/*
38 * Allocate an AEAD request structure with extra space for SG and IV.
39 *
40 * For alignment considerations the IV is placed at the front, followed
41 * by the request and finally the SG list.
42 *
43 * TODO: Use spare space in skb for this where possible.
44 */
45static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen)
46{
47 unsigned int len;
48
49 len = extralen;
50
51 len += crypto_aead_ivsize(aead);
52
53 if (len) {
54 len += crypto_aead_alignmask(aead) &
55 ~(crypto_tfm_ctx_alignment() - 1);
56 len = ALIGN(len, crypto_tfm_ctx_alignment());
57 }
58
59 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
60 len = ALIGN(len, __alignof__(struct scatterlist));
61
62 len += sizeof(struct scatterlist) * nfrags;
63
64 return kmalloc(len, GFP_ATOMIC);
65}
66
67static inline void *esp_tmp_extra(void *tmp)
68{
69 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
70}
71
72static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen)
73{
74 return crypto_aead_ivsize(aead) ?
75 PTR_ALIGN((u8 *)tmp + extralen,
76 crypto_aead_alignmask(aead) + 1) : tmp + extralen;
77}
78
79static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
80{
81 struct aead_request *req;
82
83 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
84 crypto_tfm_ctx_alignment());
85 aead_request_set_tfm(req, aead);
86 return req;
87}
88
89static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
90 struct aead_request *req)
91{
92 return (void *)ALIGN((unsigned long)(req + 1) +
93 crypto_aead_reqsize(aead),
94 __alignof__(struct scatterlist));
95}
96
97static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
98{
99 struct esp_output_extra *extra = esp_tmp_extra(tmp);
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(*extra);
108
109 extra = esp_tmp_extra(tmp);
110 iv = esp_tmp_iv(aead, tmp, extralen);
111 req = esp_tmp_req(aead, iv);
112
113 /* Unref skb_frag_pages in the src scatterlist if necessary.
114 * Skip the first sg which comes from skb->data.
115 */
116 if (req->src != req->dst)
117 for (sg = sg_next(req->src); sg; sg = sg_next(sg))
118 put_page(sg_page(sg));
119}
120
121static void esp_output_done(struct crypto_async_request *base, int err)
122{
123 struct sk_buff *skb = base->data;
124 struct xfrm_offload *xo = xfrm_offload(skb);
125 void *tmp;
126 struct xfrm_state *x;
127
128 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
129 struct sec_path *sp = skb_sec_path(skb);
130
131 x = sp->xvec[sp->len - 1];
132 } else {
133 x = skb_dst(skb)->xfrm;
134 }
135
136 tmp = ESP_SKB_CB(skb)->tmp;
137 esp_ssg_unref(x, tmp);
138 kfree(tmp);
139
140 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
141 if (err) {
142 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
143 kfree_skb(skb);
144 return;
145 }
146
147 skb_push(skb, skb->data - skb_mac_header(skb));
148 secpath_reset(skb);
149 xfrm_dev_resume(skb);
150 } else {
151 xfrm_output_resume(skb, err);
152 }
153}
154
155/* Move ESP header back into place. */
156static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
157{
158 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
159 void *tmp = ESP_SKB_CB(skb)->tmp;
160 __be32 *seqhi = esp_tmp_extra(tmp);
161
162 esph->seq_no = esph->spi;
163 esph->spi = *seqhi;
164}
165
166static void esp_output_restore_header(struct sk_buff *skb)
167{
168 void *tmp = ESP_SKB_CB(skb)->tmp;
169 struct esp_output_extra *extra = esp_tmp_extra(tmp);
170
171 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
172 sizeof(__be32));
173}
174
175static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
176 struct xfrm_state *x,
177 struct ip_esp_hdr *esph,
178 struct esp_output_extra *extra)
179{
180 /* For ESN we move the header forward by 4 bytes to
181 * accomodate the high bits. We will move it back after
182 * encryption.
183 */
184 if ((x->props.flags & XFRM_STATE_ESN)) {
185 __u32 seqhi;
186 struct xfrm_offload *xo = xfrm_offload(skb);
187
188 if (xo)
189 seqhi = xo->seq.hi;
190 else
191 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
192
193 extra->esphoff = (unsigned char *)esph -
194 skb_transport_header(skb);
195 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
196 extra->seqhi = esph->spi;
197 esph->seq_no = htonl(seqhi);
198 }
199
200 esph->spi = x->id.spi;
201
202 return esph;
203}
204
205static void esp_output_done_esn(struct crypto_async_request *base, int err)
206{
207 struct sk_buff *skb = base->data;
208
209 esp_output_restore_header(skb);
210 esp_output_done(base, err);
211}
212
213static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto)
214{
215 /* Fill padding... */
216 if (tfclen) {
217 memset(tail, 0, tfclen);
218 tail += tfclen;
219 }
220 do {
221 int i;
222 for (i = 0; i < plen - 2; i++)
223 tail[i] = i + 1;
224 } while (0);
225 tail[plen - 2] = plen - 2;
226 tail[plen - 1] = proto;
227}
228
229static void esp_output_udp_encap(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
230{
231 int encap_type;
232 struct udphdr *uh;
233 __be32 *udpdata32;
234 __be16 sport, dport;
235 struct xfrm_encap_tmpl *encap = x->encap;
236 struct ip_esp_hdr *esph = esp->esph;
237
238 spin_lock_bh(&x->lock);
239 sport = encap->encap_sport;
240 dport = encap->encap_dport;
241 encap_type = encap->encap_type;
242 spin_unlock_bh(&x->lock);
243
244 uh = (struct udphdr *)esph;
245 uh->source = sport;
246 uh->dest = dport;
247 uh->len = htons(skb->len + esp->tailen
248 - skb_transport_offset(skb));
249 uh->check = 0;
250
251 switch (encap_type) {
252 default:
253 case UDP_ENCAP_ESPINUDP:
254 esph = (struct ip_esp_hdr *)(uh + 1);
255 break;
256 case UDP_ENCAP_ESPINUDP_NON_IKE:
257 udpdata32 = (__be32 *)(uh + 1);
258 udpdata32[0] = udpdata32[1] = 0;
259 esph = (struct ip_esp_hdr *)(udpdata32 + 2);
260 break;
261 }
262
263 *skb_mac_header(skb) = IPPROTO_UDP;
264 esp->esph = esph;
265}
266
267int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
268{
269 u8 *tail;
270 u8 *vaddr;
271 int nfrags;
272 int esph_offset;
273 struct page *page;
274 struct sk_buff *trailer;
275 int tailen = esp->tailen;
276
277 /* this is non-NULL only with UDP Encapsulation */
278 if (x->encap)
279 esp_output_udp_encap(x, skb, esp);
280
281 if (!skb_cloned(skb)) {
282 if (tailen <= skb_tailroom(skb)) {
283 nfrags = 1;
284 trailer = skb;
285 tail = skb_tail_pointer(trailer);
286
287 goto skip_cow;
288 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
289 && !skb_has_frag_list(skb)) {
290 int allocsize;
291 struct sock *sk = skb->sk;
292 struct page_frag *pfrag = &x->xfrag;
293
294 esp->inplace = false;
295
296 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
297
298 spin_lock_bh(&x->lock);
299
300 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
301 spin_unlock_bh(&x->lock);
302 goto cow;
303 }
304
305 page = pfrag->page;
306 get_page(page);
307
308 vaddr = kmap_atomic(page);
309
310 tail = vaddr + pfrag->offset;
311
312 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
313
314 kunmap_atomic(vaddr);
315
316 nfrags = skb_shinfo(skb)->nr_frags;
317
318 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
319 tailen);
320 skb_shinfo(skb)->nr_frags = ++nfrags;
321
322 pfrag->offset = pfrag->offset + allocsize;
323
324 spin_unlock_bh(&x->lock);
325
326 nfrags++;
327
328 skb->len += tailen;
329 skb->data_len += tailen;
330 skb->truesize += tailen;
331 if (sk && sk_fullsock(sk))
332 refcount_add(tailen, &sk->sk_wmem_alloc);
333
334 goto out;
335 }
336 }
337
338cow:
339 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
340
341 nfrags = skb_cow_data(skb, tailen, &trailer);
342 if (nfrags < 0)
343 goto out;
344 tail = skb_tail_pointer(trailer);
345 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
346
347skip_cow:
348 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
349 pskb_put(skb, trailer, tailen);
350
351out:
352 return nfrags;
353}
354EXPORT_SYMBOL_GPL(esp_output_head);
355
356int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
357{
358 u8 *iv;
359 int alen;
360 void *tmp;
361 int ivlen;
362 int assoclen;
363 int extralen;
364 struct page *page;
365 struct ip_esp_hdr *esph;
366 struct crypto_aead *aead;
367 struct aead_request *req;
368 struct scatterlist *sg, *dsg;
369 struct esp_output_extra *extra;
370 int err = -ENOMEM;
371
372 assoclen = sizeof(struct ip_esp_hdr);
373 extralen = 0;
374
375 if (x->props.flags & XFRM_STATE_ESN) {
376 extralen += sizeof(*extra);
377 assoclen += sizeof(__be32);
378 }
379
380 aead = x->data;
381 alen = crypto_aead_authsize(aead);
382 ivlen = crypto_aead_ivsize(aead);
383
384 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
385 if (!tmp)
386 goto error;
387
388 extra = esp_tmp_extra(tmp);
389 iv = esp_tmp_iv(aead, tmp, extralen);
390 req = esp_tmp_req(aead, iv);
391 sg = esp_req_sg(aead, req);
392
393 if (esp->inplace)
394 dsg = sg;
395 else
396 dsg = &sg[esp->nfrags];
397
398 esph = esp_output_set_extra(skb, x, esp->esph, extra);
399 esp->esph = esph;
400
401 sg_init_table(sg, esp->nfrags);
402 err = skb_to_sgvec(skb, sg,
403 (unsigned char *)esph - skb->data,
404 assoclen + ivlen + esp->clen + alen);
405 if (unlikely(err < 0))
406 goto error_free;
407
408 if (!esp->inplace) {
409 int allocsize;
410 struct page_frag *pfrag = &x->xfrag;
411
412 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
413
414 spin_lock_bh(&x->lock);
415 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
416 spin_unlock_bh(&x->lock);
417 goto error_free;
418 }
419
420 skb_shinfo(skb)->nr_frags = 1;
421
422 page = pfrag->page;
423 get_page(page);
424 /* replace page frags in skb with new page */
425 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
426 pfrag->offset = pfrag->offset + allocsize;
427 spin_unlock_bh(&x->lock);
428
429 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
430 err = skb_to_sgvec(skb, dsg,
431 (unsigned char *)esph - skb->data,
432 assoclen + ivlen + esp->clen + alen);
433 if (unlikely(err < 0))
434 goto error_free;
435 }
436
437 if ((x->props.flags & XFRM_STATE_ESN))
438 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
439 else
440 aead_request_set_callback(req, 0, esp_output_done, skb);
441
442 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
443 aead_request_set_ad(req, assoclen);
444
445 memset(iv, 0, ivlen);
446 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
447 min(ivlen, 8));
448
449 ESP_SKB_CB(skb)->tmp = tmp;
450 err = crypto_aead_encrypt(req);
451
452 switch (err) {
453 case -EINPROGRESS:
454 goto error;
455
456 case -ENOSPC:
457 err = NET_XMIT_DROP;
458 break;
459
460 case 0:
461 if ((x->props.flags & XFRM_STATE_ESN))
462 esp_output_restore_header(skb);
463 }
464
465 if (sg != dsg)
466 esp_ssg_unref(x, tmp);
467
468error_free:
469 kfree(tmp);
470error:
471 return err;
472}
473EXPORT_SYMBOL_GPL(esp_output_tail);
474
475static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
476{
477 int alen;
478 int blksize;
479 struct ip_esp_hdr *esph;
480 struct crypto_aead *aead;
481 struct esp_info esp;
482
483 esp.inplace = true;
484
485 esp.proto = *skb_mac_header(skb);
486 *skb_mac_header(skb) = IPPROTO_ESP;
487
488 /* skb is pure payload to encrypt */
489
490 aead = x->data;
491 alen = crypto_aead_authsize(aead);
492
493 esp.tfclen = 0;
494 if (x->tfcpad) {
495 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
496 u32 padto;
497
498 padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached));
499 if (skb->len < padto)
500 esp.tfclen = padto - skb->len;
501 }
502 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
503 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
504 esp.plen = esp.clen - skb->len - esp.tfclen;
505 esp.tailen = esp.tfclen + esp.plen + alen;
506
507 esp.esph = ip_esp_hdr(skb);
508
509 esp.nfrags = esp_output_head(x, skb, &esp);
510 if (esp.nfrags < 0)
511 return esp.nfrags;
512
513 esph = esp.esph;
514 esph->spi = x->id.spi;
515
516 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
517 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
518 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
519
520 skb_push(skb, -skb_network_offset(skb));
521
522 return esp_output_tail(x, skb, &esp);
523}
524
525static inline int esp_remove_trailer(struct sk_buff *skb)
526{
527 struct xfrm_state *x = xfrm_input_state(skb);
528 struct xfrm_offload *xo = xfrm_offload(skb);
529 struct crypto_aead *aead = x->data;
530 int alen, hlen, elen;
531 int padlen, trimlen;
532 __wsum csumdiff;
533 u8 nexthdr[2];
534 int ret;
535
536 alen = crypto_aead_authsize(aead);
537 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
538 elen = skb->len - hlen;
539
540 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) {
541 ret = xo->proto;
542 goto out;
543 }
544
545 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
546 BUG();
547
548 ret = -EINVAL;
549 padlen = nexthdr[0];
550 if (padlen + 2 + alen >= elen) {
551 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
552 padlen + 2, elen - alen);
553 goto out;
554 }
555
556 trimlen = alen + padlen + 2;
557 if (skb->ip_summed == CHECKSUM_COMPLETE) {
558 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
559 skb->csum = csum_block_sub(skb->csum, csumdiff,
560 skb->len - trimlen);
561 }
562 pskb_trim(skb, skb->len - trimlen);
563
564 ret = nexthdr[1];
565
566out:
567 return ret;
568}
569
570int esp_input_done2(struct sk_buff *skb, int err)
571{
572 const struct iphdr *iph;
573 struct xfrm_state *x = xfrm_input_state(skb);
574 struct xfrm_offload *xo = xfrm_offload(skb);
575 struct crypto_aead *aead = x->data;
576 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
577 int ihl;
578
579 if (!xo || (xo && !(xo->flags & CRYPTO_DONE)))
580 kfree(ESP_SKB_CB(skb)->tmp);
581
582 if (unlikely(err))
583 goto out;
584
585 err = esp_remove_trailer(skb);
586 if (unlikely(err < 0))
587 goto out;
588
589 iph = ip_hdr(skb);
590 ihl = iph->ihl * 4;
591
592 if (x->encap) {
593 struct xfrm_encap_tmpl *encap = x->encap;
594 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
595
596 /*
597 * 1) if the NAT-T peer's IP or port changed then
598 * advertize the change to the keying daemon.
599 * This is an inbound SA, so just compare
600 * SRC ports.
601 */
602 if (iph->saddr != x->props.saddr.a4 ||
603 uh->source != encap->encap_sport) {
604 xfrm_address_t ipaddr;
605
606 ipaddr.a4 = iph->saddr;
607 km_new_mapping(x, &ipaddr, uh->source);
608
609 /* XXX: perhaps add an extra
610 * policy check here, to see
611 * if we should allow or
612 * reject a packet from a
613 * different source
614 * address/port.
615 */
616 }
617
618 /*
619 * 2) ignore UDP/TCP checksums in case
620 * of NAT-T in Transport Mode, or
621 * perform other post-processing fixes
622 * as per draft-ietf-ipsec-udp-encaps-06,
623 * section 3.1.2
624 */
625 if (x->props.mode == XFRM_MODE_TRANSPORT)
626 skb->ip_summed = CHECKSUM_UNNECESSARY;
627 }
628
629 skb_pull_rcsum(skb, hlen);
630 if (x->props.mode == XFRM_MODE_TUNNEL)
631 skb_reset_transport_header(skb);
632 else
633 skb_set_transport_header(skb, -ihl);
634
635 /* RFC4303: Drop dummy packets without any error */
636 if (err == IPPROTO_NONE)
637 err = -EINVAL;
638
639out:
640 return err;
641}
642EXPORT_SYMBOL_GPL(esp_input_done2);
643
644static void esp_input_done(struct crypto_async_request *base, int err)
645{
646 struct sk_buff *skb = base->data;
647
648 xfrm_input_resume(skb, esp_input_done2(skb, err));
649}
650
651static void esp_input_restore_header(struct sk_buff *skb)
652{
653 esp_restore_header(skb, 0);
654 __skb_pull(skb, 4);
655}
656
657static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
658{
659 struct xfrm_state *x = xfrm_input_state(skb);
660 struct ip_esp_hdr *esph;
661
662 /* For ESN we move the header forward by 4 bytes to
663 * accomodate the high bits. We will move it back after
664 * decryption.
665 */
666 if ((x->props.flags & XFRM_STATE_ESN)) {
667 esph = skb_push(skb, 4);
668 *seqhi = esph->spi;
669 esph->spi = esph->seq_no;
670 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
671 }
672}
673
674static void esp_input_done_esn(struct crypto_async_request *base, int err)
675{
676 struct sk_buff *skb = base->data;
677
678 esp_input_restore_header(skb);
679 esp_input_done(base, err);
680}
681
682/*
683 * Note: detecting truncated vs. non-truncated authentication data is very
684 * expensive, so we only support truncated data, which is the recommended
685 * and common case.
686 */
687static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
688{
689 struct crypto_aead *aead = x->data;
690 struct aead_request *req;
691 struct sk_buff *trailer;
692 int ivlen = crypto_aead_ivsize(aead);
693 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
694 int nfrags;
695 int assoclen;
696 int seqhilen;
697 __be32 *seqhi;
698 void *tmp;
699 u8 *iv;
700 struct scatterlist *sg;
701 int err = -EINVAL;
702
703 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
704 goto out;
705
706 if (elen <= 0)
707 goto out;
708
709 assoclen = sizeof(struct ip_esp_hdr);
710 seqhilen = 0;
711
712 if (x->props.flags & XFRM_STATE_ESN) {
713 seqhilen += sizeof(__be32);
714 assoclen += seqhilen;
715 }
716
717 if (!skb_cloned(skb)) {
718 if (!skb_is_nonlinear(skb)) {
719 nfrags = 1;
720
721 goto skip_cow;
722 } else if (!skb_has_frag_list(skb)) {
723 nfrags = skb_shinfo(skb)->nr_frags;
724 nfrags++;
725
726 goto skip_cow;
727 }
728 }
729
730 err = skb_cow_data(skb, 0, &trailer);
731 if (err < 0)
732 goto out;
733
734 nfrags = err;
735
736skip_cow:
737 err = -ENOMEM;
738 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
739 if (!tmp)
740 goto out;
741
742 ESP_SKB_CB(skb)->tmp = tmp;
743 seqhi = esp_tmp_extra(tmp);
744 iv = esp_tmp_iv(aead, tmp, seqhilen);
745 req = esp_tmp_req(aead, iv);
746 sg = esp_req_sg(aead, req);
747
748 esp_input_set_header(skb, seqhi);
749
750 sg_init_table(sg, nfrags);
751 err = skb_to_sgvec(skb, sg, 0, skb->len);
752 if (unlikely(err < 0)) {
753 kfree(tmp);
754 goto out;
755 }
756
757 skb->ip_summed = CHECKSUM_NONE;
758
759 if ((x->props.flags & XFRM_STATE_ESN))
760 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
761 else
762 aead_request_set_callback(req, 0, esp_input_done, skb);
763
764 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
765 aead_request_set_ad(req, assoclen);
766
767 err = crypto_aead_decrypt(req);
768 if (err == -EINPROGRESS)
769 goto out;
770
771 if ((x->props.flags & XFRM_STATE_ESN))
772 esp_input_restore_header(skb);
773
774 err = esp_input_done2(skb, err);
775
776out:
777 return err;
778}
779
780static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
781{
782 struct crypto_aead *aead = x->data;
783 u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
784 unsigned int net_adj;
785
786 switch (x->props.mode) {
787 case XFRM_MODE_TRANSPORT:
788 case XFRM_MODE_BEET:
789 net_adj = sizeof(struct iphdr);
790 break;
791 case XFRM_MODE_TUNNEL:
792 net_adj = 0;
793 break;
794 default:
795 BUG();
796 }
797
798 return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
799 net_adj) & ~(blksize - 1)) + net_adj - 2;
800}
801
802static int esp4_err(struct sk_buff *skb, u32 info)
803{
804 struct net *net = dev_net(skb->dev);
805 const struct iphdr *iph = (const struct iphdr *)skb->data;
806 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
807 struct xfrm_state *x;
808
809 switch (icmp_hdr(skb)->type) {
810 case ICMP_DEST_UNREACH:
811 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
812 return 0;
813 case ICMP_REDIRECT:
814 break;
815 default:
816 return 0;
817 }
818
819 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
820 esph->spi, IPPROTO_ESP, AF_INET);
821 if (!x)
822 return 0;
823
824 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
825 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP);
826 else
827 ipv4_redirect(skb, net, 0, IPPROTO_ESP);
828 xfrm_state_put(x);
829
830 return 0;
831}
832
833static void esp_destroy(struct xfrm_state *x)
834{
835 struct crypto_aead *aead = x->data;
836
837 if (!aead)
838 return;
839
840 crypto_free_aead(aead);
841}
842
843static int esp_init_aead(struct xfrm_state *x)
844{
845 char aead_name[CRYPTO_MAX_ALG_NAME];
846 struct crypto_aead *aead;
847 int err;
848
849 err = -ENAMETOOLONG;
850 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
851 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
852 goto error;
853
854 aead = crypto_alloc_aead(aead_name, 0, 0);
855 err = PTR_ERR(aead);
856 if (IS_ERR(aead))
857 goto error;
858
859 x->data = aead;
860
861 err = crypto_aead_setkey(aead, x->aead->alg_key,
862 (x->aead->alg_key_len + 7) / 8);
863 if (err)
864 goto error;
865
866 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
867 if (err)
868 goto error;
869
870error:
871 return err;
872}
873
874static int esp_init_authenc(struct xfrm_state *x)
875{
876 struct crypto_aead *aead;
877 struct crypto_authenc_key_param *param;
878 struct rtattr *rta;
879 char *key;
880 char *p;
881 char authenc_name[CRYPTO_MAX_ALG_NAME];
882 unsigned int keylen;
883 int err;
884
885 err = -EINVAL;
886 if (!x->ealg)
887 goto error;
888
889 err = -ENAMETOOLONG;
890
891 if ((x->props.flags & XFRM_STATE_ESN)) {
892 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
893 "%s%sauthencesn(%s,%s)%s",
894 x->geniv ?: "", x->geniv ? "(" : "",
895 x->aalg ? x->aalg->alg_name : "digest_null",
896 x->ealg->alg_name,
897 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
898 goto error;
899 } else {
900 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
901 "%s%sauthenc(%s,%s)%s",
902 x->geniv ?: "", x->geniv ? "(" : "",
903 x->aalg ? x->aalg->alg_name : "digest_null",
904 x->ealg->alg_name,
905 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
906 goto error;
907 }
908
909 aead = crypto_alloc_aead(authenc_name, 0, 0);
910 err = PTR_ERR(aead);
911 if (IS_ERR(aead))
912 goto error;
913
914 x->data = aead;
915
916 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
917 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
918 err = -ENOMEM;
919 key = kmalloc(keylen, GFP_KERNEL);
920 if (!key)
921 goto error;
922
923 p = key;
924 rta = (void *)p;
925 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
926 rta->rta_len = RTA_LENGTH(sizeof(*param));
927 param = RTA_DATA(rta);
928 p += RTA_SPACE(sizeof(*param));
929
930 if (x->aalg) {
931 struct xfrm_algo_desc *aalg_desc;
932
933 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
934 p += (x->aalg->alg_key_len + 7) / 8;
935
936 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
937 BUG_ON(!aalg_desc);
938
939 err = -EINVAL;
940 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
941 crypto_aead_authsize(aead)) {
942 pr_info("ESP: %s digestsize %u != %hu\n",
943 x->aalg->alg_name,
944 crypto_aead_authsize(aead),
945 aalg_desc->uinfo.auth.icv_fullbits / 8);
946 goto free_key;
947 }
948
949 err = crypto_aead_setauthsize(
950 aead, x->aalg->alg_trunc_len / 8);
951 if (err)
952 goto free_key;
953 }
954
955 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
956 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
957
958 err = crypto_aead_setkey(aead, key, keylen);
959
960free_key:
961 kfree(key);
962
963error:
964 return err;
965}
966
967static int esp_init_state(struct xfrm_state *x)
968{
969 struct crypto_aead *aead;
970 u32 align;
971 int err;
972
973 x->data = NULL;
974
975 if (x->aead)
976 err = esp_init_aead(x);
977 else
978 err = esp_init_authenc(x);
979
980 if (err)
981 goto error;
982
983 aead = x->data;
984
985 x->props.header_len = sizeof(struct ip_esp_hdr) +
986 crypto_aead_ivsize(aead);
987 if (x->props.mode == XFRM_MODE_TUNNEL)
988 x->props.header_len += sizeof(struct iphdr);
989 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
990 x->props.header_len += IPV4_BEET_PHMAXLEN;
991 if (x->encap) {
992 struct xfrm_encap_tmpl *encap = x->encap;
993
994 switch (encap->encap_type) {
995 default:
996 err = -EINVAL;
997 goto error;
998 case UDP_ENCAP_ESPINUDP:
999 x->props.header_len += sizeof(struct udphdr);
1000 break;
1001 case UDP_ENCAP_ESPINUDP_NON_IKE:
1002 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
1003 break;
1004 }
1005 }
1006
1007 align = ALIGN(crypto_aead_blocksize(aead), 4);
1008 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1009
1010error:
1011 return err;
1012}
1013
1014static int esp4_rcv_cb(struct sk_buff *skb, int err)
1015{
1016 return 0;
1017}
1018
1019static const struct xfrm_type esp_type =
1020{
1021 .description = "ESP4",
1022 .owner = THIS_MODULE,
1023 .proto = IPPROTO_ESP,
1024 .flags = XFRM_TYPE_REPLAY_PROT,
1025 .init_state = esp_init_state,
1026 .destructor = esp_destroy,
1027 .get_mtu = esp4_get_mtu,
1028 .input = esp_input,
1029 .output = esp_output,
1030};
1031
1032static struct xfrm4_protocol esp4_protocol = {
1033 .handler = xfrm4_rcv,
1034 .input_handler = xfrm_input,
1035 .cb_handler = esp4_rcv_cb,
1036 .err_handler = esp4_err,
1037 .priority = 0,
1038};
1039
1040static int __init esp4_init(void)
1041{
1042 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1043 pr_info("%s: can't add xfrm type\n", __func__);
1044 return -EAGAIN;
1045 }
1046 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1047 pr_info("%s: can't add protocol\n", __func__);
1048 xfrm_unregister_type(&esp_type, AF_INET);
1049 return -EAGAIN;
1050 }
1051 return 0;
1052}
1053
1054static void __exit esp4_fini(void)
1055{
1056 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1057 pr_info("%s: can't remove protocol\n", __func__);
1058 if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
1059 pr_info("%s: can't remove xfrm type\n", __func__);
1060}
1061
1062module_init(esp4_init);
1063module_exit(esp4_fini);
1064MODULE_LICENSE("GPL");
1065MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
1066