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[mirror_ubuntu-artful-kernel.git] / net / ipv4 / esp4.c
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
23 struct esp_skb_cb {
24 struct xfrm_skb_cb xfrm;
25 void *tmp;
26 };
27
28 struct 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
35 static 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 */
45 static 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
67 static inline void *esp_tmp_extra(void *tmp)
68 {
69 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
70 }
71
72 static 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
79 static 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
89 static 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
97 static 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
121 static void esp_output_done(struct crypto_async_request *base, int err)
122 {
123 struct sk_buff *skb = base->data;
124 void *tmp;
125 struct dst_entry *dst = skb_dst(skb);
126 struct xfrm_state *x = dst->xfrm;
127
128 tmp = ESP_SKB_CB(skb)->tmp;
129 esp_ssg_unref(x, tmp);
130 kfree(tmp);
131 xfrm_output_resume(skb, err);
132 }
133
134 /* Move ESP header back into place. */
135 static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
136 {
137 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
138 void *tmp = ESP_SKB_CB(skb)->tmp;
139 __be32 *seqhi = esp_tmp_extra(tmp);
140
141 esph->seq_no = esph->spi;
142 esph->spi = *seqhi;
143 }
144
145 static void esp_output_restore_header(struct sk_buff *skb)
146 {
147 void *tmp = ESP_SKB_CB(skb)->tmp;
148 struct esp_output_extra *extra = esp_tmp_extra(tmp);
149
150 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
151 sizeof(__be32));
152 }
153
154 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
155 struct xfrm_state *x,
156 struct ip_esp_hdr *esph,
157 struct esp_output_extra *extra)
158 {
159 /* For ESN we move the header forward by 4 bytes to
160 * accomodate the high bits. We will move it back after
161 * encryption.
162 */
163 if ((x->props.flags & XFRM_STATE_ESN)) {
164 __u32 seqhi;
165 struct xfrm_offload *xo = xfrm_offload(skb);
166
167 if (xo)
168 seqhi = xo->seq.hi;
169 else
170 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
171
172 extra->esphoff = (unsigned char *)esph -
173 skb_transport_header(skb);
174 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
175 extra->seqhi = esph->spi;
176 esph->seq_no = htonl(seqhi);
177 }
178
179 esph->spi = x->id.spi;
180
181 return esph;
182 }
183
184 static void esp_output_done_esn(struct crypto_async_request *base, int err)
185 {
186 struct sk_buff *skb = base->data;
187
188 esp_output_restore_header(skb);
189 esp_output_done(base, err);
190 }
191
192 static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto)
193 {
194 /* Fill padding... */
195 if (tfclen) {
196 memset(tail, 0, tfclen);
197 tail += tfclen;
198 }
199 do {
200 int i;
201 for (i = 0; i < plen - 2; i++)
202 tail[i] = i + 1;
203 } while (0);
204 tail[plen - 2] = plen - 2;
205 tail[plen - 1] = proto;
206 }
207
208 static void esp_output_udp_encap(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
209 {
210 int encap_type;
211 struct udphdr *uh;
212 __be32 *udpdata32;
213 __be16 sport, dport;
214 struct xfrm_encap_tmpl *encap = x->encap;
215 struct ip_esp_hdr *esph = esp->esph;
216
217 spin_lock_bh(&x->lock);
218 sport = encap->encap_sport;
219 dport = encap->encap_dport;
220 encap_type = encap->encap_type;
221 spin_unlock_bh(&x->lock);
222
223 uh = (struct udphdr *)esph;
224 uh->source = sport;
225 uh->dest = dport;
226 uh->len = htons(skb->len + esp->tailen
227 - skb_transport_offset(skb));
228 uh->check = 0;
229
230 switch (encap_type) {
231 default:
232 case UDP_ENCAP_ESPINUDP:
233 esph = (struct ip_esp_hdr *)(uh + 1);
234 break;
235 case UDP_ENCAP_ESPINUDP_NON_IKE:
236 udpdata32 = (__be32 *)(uh + 1);
237 udpdata32[0] = udpdata32[1] = 0;
238 esph = (struct ip_esp_hdr *)(udpdata32 + 2);
239 break;
240 }
241
242 *skb_mac_header(skb) = IPPROTO_UDP;
243 esp->esph = esph;
244 }
245
246 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
247 {
248 u8 *tail;
249 u8 *vaddr;
250 int nfrags;
251 int esph_offset;
252 struct page *page;
253 struct sk_buff *trailer;
254 int tailen = esp->tailen;
255
256 /* this is non-NULL only with UDP Encapsulation */
257 if (x->encap)
258 esp_output_udp_encap(x, skb, esp);
259
260 if (!skb_cloned(skb)) {
261 if (tailen <= skb_tailroom(skb)) {
262 nfrags = 1;
263 trailer = skb;
264 tail = skb_tail_pointer(trailer);
265
266 goto skip_cow;
267 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
268 && !skb_has_frag_list(skb)) {
269 int allocsize;
270 struct sock *sk = skb->sk;
271 struct page_frag *pfrag = &x->xfrag;
272
273 esp->inplace = false;
274
275 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
276
277 spin_lock_bh(&x->lock);
278
279 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
280 spin_unlock_bh(&x->lock);
281 goto cow;
282 }
283
284 page = pfrag->page;
285 get_page(page);
286
287 vaddr = kmap_atomic(page);
288
289 tail = vaddr + pfrag->offset;
290
291 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
292
293 kunmap_atomic(vaddr);
294
295 nfrags = skb_shinfo(skb)->nr_frags;
296
297 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
298 tailen);
299 skb_shinfo(skb)->nr_frags = ++nfrags;
300
301 pfrag->offset = pfrag->offset + allocsize;
302
303 spin_unlock_bh(&x->lock);
304
305 nfrags++;
306
307 skb->len += tailen;
308 skb->data_len += tailen;
309 skb->truesize += tailen;
310 if (sk)
311 refcount_add(tailen, &sk->sk_wmem_alloc);
312
313 goto out;
314 }
315 }
316
317 cow:
318 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
319
320 nfrags = skb_cow_data(skb, tailen, &trailer);
321 if (nfrags < 0)
322 goto out;
323 tail = skb_tail_pointer(trailer);
324 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
325
326 skip_cow:
327 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
328 pskb_put(skb, trailer, tailen);
329
330 out:
331 return nfrags;
332 }
333 EXPORT_SYMBOL_GPL(esp_output_head);
334
335 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
336 {
337 u8 *iv;
338 int alen;
339 void *tmp;
340 int ivlen;
341 int assoclen;
342 int extralen;
343 struct page *page;
344 struct ip_esp_hdr *esph;
345 struct crypto_aead *aead;
346 struct aead_request *req;
347 struct scatterlist *sg, *dsg;
348 struct esp_output_extra *extra;
349 int err = -ENOMEM;
350
351 assoclen = sizeof(struct ip_esp_hdr);
352 extralen = 0;
353
354 if (x->props.flags & XFRM_STATE_ESN) {
355 extralen += sizeof(*extra);
356 assoclen += sizeof(__be32);
357 }
358
359 aead = x->data;
360 alen = crypto_aead_authsize(aead);
361 ivlen = crypto_aead_ivsize(aead);
362
363 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
364 if (!tmp)
365 goto error;
366
367 extra = esp_tmp_extra(tmp);
368 iv = esp_tmp_iv(aead, tmp, extralen);
369 req = esp_tmp_req(aead, iv);
370 sg = esp_req_sg(aead, req);
371
372 if (esp->inplace)
373 dsg = sg;
374 else
375 dsg = &sg[esp->nfrags];
376
377 esph = esp_output_set_extra(skb, x, esp->esph, extra);
378 esp->esph = esph;
379
380 sg_init_table(sg, esp->nfrags);
381 err = skb_to_sgvec(skb, sg,
382 (unsigned char *)esph - skb->data,
383 assoclen + ivlen + esp->clen + alen);
384 if (unlikely(err < 0))
385 goto error_free;
386
387 if (!esp->inplace) {
388 int allocsize;
389 struct page_frag *pfrag = &x->xfrag;
390
391 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
392
393 spin_lock_bh(&x->lock);
394 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
395 spin_unlock_bh(&x->lock);
396 goto error_free;
397 }
398
399 skb_shinfo(skb)->nr_frags = 1;
400
401 page = pfrag->page;
402 get_page(page);
403 /* replace page frags in skb with new page */
404 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
405 pfrag->offset = pfrag->offset + allocsize;
406 spin_unlock_bh(&x->lock);
407
408 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
409 err = skb_to_sgvec(skb, dsg,
410 (unsigned char *)esph - skb->data,
411 assoclen + ivlen + esp->clen + alen);
412 if (unlikely(err < 0))
413 goto error_free;
414 }
415
416 if ((x->props.flags & XFRM_STATE_ESN))
417 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
418 else
419 aead_request_set_callback(req, 0, esp_output_done, skb);
420
421 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
422 aead_request_set_ad(req, assoclen);
423
424 memset(iv, 0, ivlen);
425 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
426 min(ivlen, 8));
427
428 ESP_SKB_CB(skb)->tmp = tmp;
429 err = crypto_aead_encrypt(req);
430
431 switch (err) {
432 case -EINPROGRESS:
433 goto error;
434
435 case -EBUSY:
436 err = NET_XMIT_DROP;
437 break;
438
439 case 0:
440 if ((x->props.flags & XFRM_STATE_ESN))
441 esp_output_restore_header(skb);
442 }
443
444 if (sg != dsg)
445 esp_ssg_unref(x, tmp);
446
447 error_free:
448 kfree(tmp);
449 error:
450 return err;
451 }
452 EXPORT_SYMBOL_GPL(esp_output_tail);
453
454 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
455 {
456 int alen;
457 int blksize;
458 struct ip_esp_hdr *esph;
459 struct crypto_aead *aead;
460 struct esp_info esp;
461
462 esp.inplace = true;
463
464 esp.proto = *skb_mac_header(skb);
465 *skb_mac_header(skb) = IPPROTO_ESP;
466
467 /* skb is pure payload to encrypt */
468
469 aead = x->data;
470 alen = crypto_aead_authsize(aead);
471
472 esp.tfclen = 0;
473 if (x->tfcpad) {
474 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
475 u32 padto;
476
477 padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached));
478 if (skb->len < padto)
479 esp.tfclen = padto - skb->len;
480 }
481 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
482 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
483 esp.plen = esp.clen - skb->len - esp.tfclen;
484 esp.tailen = esp.tfclen + esp.plen + alen;
485
486 esp.esph = ip_esp_hdr(skb);
487
488 esp.nfrags = esp_output_head(x, skb, &esp);
489 if (esp.nfrags < 0)
490 return esp.nfrags;
491
492 esph = esp.esph;
493 esph->spi = x->id.spi;
494
495 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
496 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
497 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
498
499 skb_push(skb, -skb_network_offset(skb));
500
501 return esp_output_tail(x, skb, &esp);
502 }
503
504 int esp_input_done2(struct sk_buff *skb, int err)
505 {
506 const struct iphdr *iph;
507 struct xfrm_state *x = xfrm_input_state(skb);
508 struct xfrm_offload *xo = xfrm_offload(skb);
509 struct crypto_aead *aead = x->data;
510 int alen = crypto_aead_authsize(aead);
511 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
512 int elen = skb->len - hlen;
513 int ihl;
514 u8 nexthdr[2];
515 int padlen;
516
517 if (!xo || (xo && !(xo->flags & CRYPTO_DONE)))
518 kfree(ESP_SKB_CB(skb)->tmp);
519
520 if (unlikely(err))
521 goto out;
522
523 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
524 BUG();
525
526 err = -EINVAL;
527 padlen = nexthdr[0];
528 if (padlen + 2 + alen >= elen)
529 goto out;
530
531 /* ... check padding bits here. Silly. :-) */
532
533 iph = ip_hdr(skb);
534 ihl = iph->ihl * 4;
535
536 if (x->encap) {
537 struct xfrm_encap_tmpl *encap = x->encap;
538 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
539
540 /*
541 * 1) if the NAT-T peer's IP or port changed then
542 * advertize the change to the keying daemon.
543 * This is an inbound SA, so just compare
544 * SRC ports.
545 */
546 if (iph->saddr != x->props.saddr.a4 ||
547 uh->source != encap->encap_sport) {
548 xfrm_address_t ipaddr;
549
550 ipaddr.a4 = iph->saddr;
551 km_new_mapping(x, &ipaddr, uh->source);
552
553 /* XXX: perhaps add an extra
554 * policy check here, to see
555 * if we should allow or
556 * reject a packet from a
557 * different source
558 * address/port.
559 */
560 }
561
562 /*
563 * 2) ignore UDP/TCP checksums in case
564 * of NAT-T in Transport Mode, or
565 * perform other post-processing fixes
566 * as per draft-ietf-ipsec-udp-encaps-06,
567 * section 3.1.2
568 */
569 if (x->props.mode == XFRM_MODE_TRANSPORT)
570 skb->ip_summed = CHECKSUM_UNNECESSARY;
571 }
572
573 pskb_trim(skb, skb->len - alen - padlen - 2);
574 __skb_pull(skb, hlen);
575 if (x->props.mode == XFRM_MODE_TUNNEL)
576 skb_reset_transport_header(skb);
577 else
578 skb_set_transport_header(skb, -ihl);
579
580 err = nexthdr[1];
581
582 /* RFC4303: Drop dummy packets without any error */
583 if (err == IPPROTO_NONE)
584 err = -EINVAL;
585
586 out:
587 return err;
588 }
589 EXPORT_SYMBOL_GPL(esp_input_done2);
590
591 static void esp_input_done(struct crypto_async_request *base, int err)
592 {
593 struct sk_buff *skb = base->data;
594
595 xfrm_input_resume(skb, esp_input_done2(skb, err));
596 }
597
598 static void esp_input_restore_header(struct sk_buff *skb)
599 {
600 esp_restore_header(skb, 0);
601 __skb_pull(skb, 4);
602 }
603
604 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
605 {
606 struct xfrm_state *x = xfrm_input_state(skb);
607 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)skb->data;
608
609 /* For ESN we move the header forward by 4 bytes to
610 * accomodate the high bits. We will move it back after
611 * decryption.
612 */
613 if ((x->props.flags & XFRM_STATE_ESN)) {
614 esph = skb_push(skb, 4);
615 *seqhi = esph->spi;
616 esph->spi = esph->seq_no;
617 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
618 }
619 }
620
621 static void esp_input_done_esn(struct crypto_async_request *base, int err)
622 {
623 struct sk_buff *skb = base->data;
624
625 esp_input_restore_header(skb);
626 esp_input_done(base, err);
627 }
628
629 /*
630 * Note: detecting truncated vs. non-truncated authentication data is very
631 * expensive, so we only support truncated data, which is the recommended
632 * and common case.
633 */
634 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
635 {
636 struct ip_esp_hdr *esph;
637 struct crypto_aead *aead = x->data;
638 struct aead_request *req;
639 struct sk_buff *trailer;
640 int ivlen = crypto_aead_ivsize(aead);
641 int elen = skb->len - sizeof(*esph) - ivlen;
642 int nfrags;
643 int assoclen;
644 int seqhilen;
645 __be32 *seqhi;
646 void *tmp;
647 u8 *iv;
648 struct scatterlist *sg;
649 int err = -EINVAL;
650
651 if (!pskb_may_pull(skb, sizeof(*esph) + ivlen))
652 goto out;
653
654 if (elen <= 0)
655 goto out;
656
657 assoclen = sizeof(*esph);
658 seqhilen = 0;
659
660 if (x->props.flags & XFRM_STATE_ESN) {
661 seqhilen += sizeof(__be32);
662 assoclen += seqhilen;
663 }
664
665 if (!skb_cloned(skb)) {
666 if (!skb_is_nonlinear(skb)) {
667 nfrags = 1;
668
669 goto skip_cow;
670 } else if (!skb_has_frag_list(skb)) {
671 nfrags = skb_shinfo(skb)->nr_frags;
672 nfrags++;
673
674 goto skip_cow;
675 }
676 }
677
678 err = skb_cow_data(skb, 0, &trailer);
679 if (err < 0)
680 goto out;
681
682 nfrags = err;
683
684 skip_cow:
685 err = -ENOMEM;
686 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
687 if (!tmp)
688 goto out;
689
690 ESP_SKB_CB(skb)->tmp = tmp;
691 seqhi = esp_tmp_extra(tmp);
692 iv = esp_tmp_iv(aead, tmp, seqhilen);
693 req = esp_tmp_req(aead, iv);
694 sg = esp_req_sg(aead, req);
695
696 esp_input_set_header(skb, seqhi);
697
698 sg_init_table(sg, nfrags);
699 err = skb_to_sgvec(skb, sg, 0, skb->len);
700 if (unlikely(err < 0)) {
701 kfree(tmp);
702 goto out;
703 }
704
705 skb->ip_summed = CHECKSUM_NONE;
706
707 if ((x->props.flags & XFRM_STATE_ESN))
708 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
709 else
710 aead_request_set_callback(req, 0, esp_input_done, skb);
711
712 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
713 aead_request_set_ad(req, assoclen);
714
715 err = crypto_aead_decrypt(req);
716 if (err == -EINPROGRESS)
717 goto out;
718
719 if ((x->props.flags & XFRM_STATE_ESN))
720 esp_input_restore_header(skb);
721
722 err = esp_input_done2(skb, err);
723
724 out:
725 return err;
726 }
727
728 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
729 {
730 struct crypto_aead *aead = x->data;
731 u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
732 unsigned int net_adj;
733
734 switch (x->props.mode) {
735 case XFRM_MODE_TRANSPORT:
736 case XFRM_MODE_BEET:
737 net_adj = sizeof(struct iphdr);
738 break;
739 case XFRM_MODE_TUNNEL:
740 net_adj = 0;
741 break;
742 default:
743 BUG();
744 }
745
746 return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
747 net_adj) & ~(blksize - 1)) + net_adj - 2;
748 }
749
750 static int esp4_err(struct sk_buff *skb, u32 info)
751 {
752 struct net *net = dev_net(skb->dev);
753 const struct iphdr *iph = (const struct iphdr *)skb->data;
754 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
755 struct xfrm_state *x;
756
757 switch (icmp_hdr(skb)->type) {
758 case ICMP_DEST_UNREACH:
759 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
760 return 0;
761 case ICMP_REDIRECT:
762 break;
763 default:
764 return 0;
765 }
766
767 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
768 esph->spi, IPPROTO_ESP, AF_INET);
769 if (!x)
770 return 0;
771
772 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
773 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ESP, 0);
774 else
775 ipv4_redirect(skb, net, 0, 0, IPPROTO_ESP, 0);
776 xfrm_state_put(x);
777
778 return 0;
779 }
780
781 static void esp_destroy(struct xfrm_state *x)
782 {
783 struct crypto_aead *aead = x->data;
784
785 if (!aead)
786 return;
787
788 crypto_free_aead(aead);
789 }
790
791 static int esp_init_aead(struct xfrm_state *x)
792 {
793 char aead_name[CRYPTO_MAX_ALG_NAME];
794 struct crypto_aead *aead;
795 int err;
796 u32 mask = 0;
797
798 err = -ENAMETOOLONG;
799 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
800 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
801 goto error;
802
803 if (x->xso.offload_handle)
804 mask |= CRYPTO_ALG_ASYNC;
805
806 aead = crypto_alloc_aead(aead_name, 0, mask);
807 err = PTR_ERR(aead);
808 if (IS_ERR(aead))
809 goto error;
810
811 x->data = aead;
812
813 err = crypto_aead_setkey(aead, x->aead->alg_key,
814 (x->aead->alg_key_len + 7) / 8);
815 if (err)
816 goto error;
817
818 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
819 if (err)
820 goto error;
821
822 error:
823 return err;
824 }
825
826 static int esp_init_authenc(struct xfrm_state *x)
827 {
828 struct crypto_aead *aead;
829 struct crypto_authenc_key_param *param;
830 struct rtattr *rta;
831 char *key;
832 char *p;
833 char authenc_name[CRYPTO_MAX_ALG_NAME];
834 unsigned int keylen;
835 int err;
836 u32 mask = 0;
837
838 err = -EINVAL;
839 if (!x->ealg)
840 goto error;
841
842 err = -ENAMETOOLONG;
843
844 if ((x->props.flags & XFRM_STATE_ESN)) {
845 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
846 "%s%sauthencesn(%s,%s)%s",
847 x->geniv ?: "", x->geniv ? "(" : "",
848 x->aalg ? x->aalg->alg_name : "digest_null",
849 x->ealg->alg_name,
850 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
851 goto error;
852 } else {
853 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
854 "%s%sauthenc(%s,%s)%s",
855 x->geniv ?: "", x->geniv ? "(" : "",
856 x->aalg ? x->aalg->alg_name : "digest_null",
857 x->ealg->alg_name,
858 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
859 goto error;
860 }
861
862 if (x->xso.offload_handle)
863 mask |= CRYPTO_ALG_ASYNC;
864
865 aead = crypto_alloc_aead(authenc_name, 0, mask);
866 err = PTR_ERR(aead);
867 if (IS_ERR(aead))
868 goto error;
869
870 x->data = aead;
871
872 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
873 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
874 err = -ENOMEM;
875 key = kmalloc(keylen, GFP_KERNEL);
876 if (!key)
877 goto error;
878
879 p = key;
880 rta = (void *)p;
881 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
882 rta->rta_len = RTA_LENGTH(sizeof(*param));
883 param = RTA_DATA(rta);
884 p += RTA_SPACE(sizeof(*param));
885
886 if (x->aalg) {
887 struct xfrm_algo_desc *aalg_desc;
888
889 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
890 p += (x->aalg->alg_key_len + 7) / 8;
891
892 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
893 BUG_ON(!aalg_desc);
894
895 err = -EINVAL;
896 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
897 crypto_aead_authsize(aead)) {
898 pr_info("ESP: %s digestsize %u != %hu\n",
899 x->aalg->alg_name,
900 crypto_aead_authsize(aead),
901 aalg_desc->uinfo.auth.icv_fullbits / 8);
902 goto free_key;
903 }
904
905 err = crypto_aead_setauthsize(
906 aead, x->aalg->alg_trunc_len / 8);
907 if (err)
908 goto free_key;
909 }
910
911 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
912 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
913
914 err = crypto_aead_setkey(aead, key, keylen);
915
916 free_key:
917 kfree(key);
918
919 error:
920 return err;
921 }
922
923 static int esp_init_state(struct xfrm_state *x)
924 {
925 struct crypto_aead *aead;
926 u32 align;
927 int err;
928
929 x->data = NULL;
930
931 if (x->aead)
932 err = esp_init_aead(x);
933 else
934 err = esp_init_authenc(x);
935
936 if (err)
937 goto error;
938
939 aead = x->data;
940
941 x->props.header_len = sizeof(struct ip_esp_hdr) +
942 crypto_aead_ivsize(aead);
943 if (x->props.mode == XFRM_MODE_TUNNEL)
944 x->props.header_len += sizeof(struct iphdr);
945 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
946 x->props.header_len += IPV4_BEET_PHMAXLEN;
947 if (x->encap) {
948 struct xfrm_encap_tmpl *encap = x->encap;
949
950 switch (encap->encap_type) {
951 default:
952 goto error;
953 case UDP_ENCAP_ESPINUDP:
954 x->props.header_len += sizeof(struct udphdr);
955 break;
956 case UDP_ENCAP_ESPINUDP_NON_IKE:
957 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
958 break;
959 }
960 }
961
962 align = ALIGN(crypto_aead_blocksize(aead), 4);
963 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
964
965 error:
966 return err;
967 }
968
969 static int esp4_rcv_cb(struct sk_buff *skb, int err)
970 {
971 return 0;
972 }
973
974 static const struct xfrm_type esp_type =
975 {
976 .description = "ESP4",
977 .owner = THIS_MODULE,
978 .proto = IPPROTO_ESP,
979 .flags = XFRM_TYPE_REPLAY_PROT,
980 .init_state = esp_init_state,
981 .destructor = esp_destroy,
982 .get_mtu = esp4_get_mtu,
983 .input = esp_input,
984 .output = esp_output,
985 };
986
987 static struct xfrm4_protocol esp4_protocol = {
988 .handler = xfrm4_rcv,
989 .input_handler = xfrm_input,
990 .cb_handler = esp4_rcv_cb,
991 .err_handler = esp4_err,
992 .priority = 0,
993 };
994
995 static int __init esp4_init(void)
996 {
997 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
998 pr_info("%s: can't add xfrm type\n", __func__);
999 return -EAGAIN;
1000 }
1001 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1002 pr_info("%s: can't add protocol\n", __func__);
1003 xfrm_unregister_type(&esp_type, AF_INET);
1004 return -EAGAIN;
1005 }
1006 return 0;
1007 }
1008
1009 static void __exit esp4_fini(void)
1010 {
1011 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1012 pr_info("%s: can't remove protocol\n", __func__);
1013 if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
1014 pr_info("%s: can't remove xfrm type\n", __func__);
1015 }
1016
1017 module_init(esp4_init);
1018 module_exit(esp4_fini);
1019 MODULE_LICENSE("GPL");
1020 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
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