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