xref: /openbmc/linux/net/ipv6/esp6.c (revision 2127c01b) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C)2002 USAGI/WIDE Project
4  *
5  * Authors
6  *
7  *	Mitsuru KANDA @USAGI       : IPv6 Support
8  *	Kazunori MIYAZAWA @USAGI   :
9  *	Kunihiro Ishiguro <kunihiro@ipinfusion.com>
10  *
11  *	This file is derived from net/ipv4/esp.c
12  */
13 
14 #define pr_fmt(fmt) "IPv6: " fmt
15 
16 #include <crypto/aead.h>
17 #include <crypto/authenc.h>
18 #include <linux/err.h>
19 #include <linux/module.h>
20 #include <net/ip.h>
21 #include <net/xfrm.h>
22 #include <net/esp.h>
23 #include <linux/scatterlist.h>
24 #include <linux/kernel.h>
25 #include <linux/pfkeyv2.h>
26 #include <linux/random.h>
27 #include <linux/slab.h>
28 #include <linux/spinlock.h>
29 #include <net/ip6_route.h>
30 #include <net/icmp.h>
31 #include <net/ipv6.h>
32 #include <net/protocol.h>
33 #include <linux/icmpv6.h>
34 
35 #include <linux/highmem.h>
36 
37 struct esp_skb_cb {
38 	struct xfrm_skb_cb xfrm;
39 	void *tmp;
40 };
41 
42 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
43 
44 /*
45  * Allocate an AEAD request structure with extra space for SG and IV.
46  *
47  * For alignment considerations the upper 32 bits of the sequence number are
48  * placed at the front, if present. Followed by the IV, the request and finally
49  * the SG list.
50  *
51  * TODO: Use spare space in skb for this where possible.
52  */
53 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
54 {
55 	unsigned int len;
56 
57 	len = seqihlen;
58 
59 	len += crypto_aead_ivsize(aead);
60 
61 	if (len) {
62 		len += crypto_aead_alignmask(aead) &
63 		       ~(crypto_tfm_ctx_alignment() - 1);
64 		len = ALIGN(len, crypto_tfm_ctx_alignment());
65 	}
66 
67 	len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
68 	len = ALIGN(len, __alignof__(struct scatterlist));
69 
70 	len += sizeof(struct scatterlist) * nfrags;
71 
72 	return kmalloc(len, GFP_ATOMIC);
73 }
74 
75 static inline __be32 *esp_tmp_seqhi(void *tmp)
76 {
77 	return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
78 }
79 
80 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
81 {
82 	return crypto_aead_ivsize(aead) ?
83 	       PTR_ALIGN((u8 *)tmp + seqhilen,
84 			 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
85 }
86 
87 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
88 {
89 	struct aead_request *req;
90 
91 	req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
92 				crypto_tfm_ctx_alignment());
93 	aead_request_set_tfm(req, aead);
94 	return req;
95 }
96 
97 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
98 					     struct aead_request *req)
99 {
100 	return (void *)ALIGN((unsigned long)(req + 1) +
101 			     crypto_aead_reqsize(aead),
102 			     __alignof__(struct scatterlist));
103 }
104 
105 static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
106 {
107 	struct crypto_aead *aead = x->data;
108 	int seqhilen = 0;
109 	u8 *iv;
110 	struct aead_request *req;
111 	struct scatterlist *sg;
112 
113 	if (x->props.flags & XFRM_STATE_ESN)
114 		seqhilen += sizeof(__be32);
115 
116 	iv = esp_tmp_iv(aead, tmp, seqhilen);
117 	req = esp_tmp_req(aead, iv);
118 
119 	/* Unref skb_frag_pages in the src scatterlist if necessary.
120 	 * Skip the first sg which comes from skb->data.
121 	 */
122 	if (req->src != req->dst)
123 		for (sg = sg_next(req->src); sg; sg = sg_next(sg))
124 			put_page(sg_page(sg));
125 }
126 
127 static void esp_output_done(struct crypto_async_request *base, int err)
128 {
129 	struct sk_buff *skb = base->data;
130 	struct xfrm_offload *xo = xfrm_offload(skb);
131 	void *tmp;
132 	struct xfrm_state *x;
133 
134 	if (xo && (xo->flags & XFRM_DEV_RESUME)) {
135 		struct sec_path *sp = skb_sec_path(skb);
136 
137 		x = sp->xvec[sp->len - 1];
138 	} else {
139 		x = skb_dst(skb)->xfrm;
140 	}
141 
142 	tmp = ESP_SKB_CB(skb)->tmp;
143 	esp_ssg_unref(x, tmp);
144 	kfree(tmp);
145 
146 	if (xo && (xo->flags & XFRM_DEV_RESUME)) {
147 		if (err) {
148 			XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
149 			kfree_skb(skb);
150 			return;
151 		}
152 
153 		skb_push(skb, skb->data - skb_mac_header(skb));
154 		secpath_reset(skb);
155 		xfrm_dev_resume(skb);
156 	} else {
157 		xfrm_output_resume(skb, err);
158 	}
159 }
160 
161 /* Move ESP header back into place. */
162 static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
163 {
164 	struct ip_esp_hdr *esph = (void *)(skb->data + offset);
165 	void *tmp = ESP_SKB_CB(skb)->tmp;
166 	__be32 *seqhi = esp_tmp_seqhi(tmp);
167 
168 	esph->seq_no = esph->spi;
169 	esph->spi = *seqhi;
170 }
171 
172 static void esp_output_restore_header(struct sk_buff *skb)
173 {
174 	esp_restore_header(skb, skb_transport_offset(skb) - sizeof(__be32));
175 }
176 
177 static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb,
178 					     struct xfrm_state *x,
179 					     struct ip_esp_hdr *esph,
180 					     __be32 *seqhi)
181 {
182 	/* For ESN we move the header forward by 4 bytes to
183 	 * accomodate the high bits.  We will move it back after
184 	 * encryption.
185 	 */
186 	if ((x->props.flags & XFRM_STATE_ESN)) {
187 		struct xfrm_offload *xo = xfrm_offload(skb);
188 
189 		esph = (void *)(skb_transport_header(skb) - sizeof(__be32));
190 		*seqhi = esph->spi;
191 		if (xo)
192 			esph->seq_no = htonl(xo->seq.hi);
193 		else
194 			esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
195 	}
196 
197 	esph->spi = x->id.spi;
198 
199 	return esph;
200 }
201 
202 static void esp_output_done_esn(struct crypto_async_request *base, int err)
203 {
204 	struct sk_buff *skb = base->data;
205 
206 	esp_output_restore_header(skb);
207 	esp_output_done(base, err);
208 }
209 
210 static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto)
211 {
212 	/* Fill padding... */
213 	if (tfclen) {
214 		memset(tail, 0, tfclen);
215 		tail += tfclen;
216 	}
217 	do {
218 		int i;
219 		for (i = 0; i < plen - 2; i++)
220 			tail[i] = i + 1;
221 	} while (0);
222 	tail[plen - 2] = plen - 2;
223 	tail[plen - 1] = proto;
224 }
225 
226 int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
227 {
228 	u8 *tail;
229 	u8 *vaddr;
230 	int nfrags;
231 	struct page *page;
232 	struct sk_buff *trailer;
233 	int tailen = esp->tailen;
234 
235 	if (!skb_cloned(skb)) {
236 		if (tailen <= skb_tailroom(skb)) {
237 			nfrags = 1;
238 			trailer = skb;
239 			tail = skb_tail_pointer(trailer);
240 
241 			goto skip_cow;
242 		} else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
243 			   && !skb_has_frag_list(skb)) {
244 			int allocsize;
245 			struct sock *sk = skb->sk;
246 			struct page_frag *pfrag = &x->xfrag;
247 
248 			esp->inplace = false;
249 
250 			allocsize = ALIGN(tailen, L1_CACHE_BYTES);
251 
252 			spin_lock_bh(&x->lock);
253 
254 			if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
255 				spin_unlock_bh(&x->lock);
256 				goto cow;
257 			}
258 
259 			page = pfrag->page;
260 			get_page(page);
261 
262 			vaddr = kmap_atomic(page);
263 
264 			tail = vaddr + pfrag->offset;
265 
266 			esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
267 
268 			kunmap_atomic(vaddr);
269 
270 			nfrags = skb_shinfo(skb)->nr_frags;
271 
272 			__skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
273 					     tailen);
274 			skb_shinfo(skb)->nr_frags = ++nfrags;
275 
276 			pfrag->offset = pfrag->offset + allocsize;
277 
278 			spin_unlock_bh(&x->lock);
279 
280 			nfrags++;
281 
282 			skb->len += tailen;
283 			skb->data_len += tailen;
284 			skb->truesize += tailen;
285 			if (sk && sk_fullsock(sk))
286 				refcount_add(tailen, &sk->sk_wmem_alloc);
287 
288 			goto out;
289 		}
290 	}
291 
292 cow:
293 	nfrags = skb_cow_data(skb, tailen, &trailer);
294 	if (nfrags < 0)
295 		goto out;
296 	tail = skb_tail_pointer(trailer);
297 
298 skip_cow:
299 	esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
300 	pskb_put(skb, trailer, tailen);
301 
302 out:
303 	return nfrags;
304 }
305 EXPORT_SYMBOL_GPL(esp6_output_head);
306 
307 int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
308 {
309 	u8 *iv;
310 	int alen;
311 	void *tmp;
312 	int ivlen;
313 	int assoclen;
314 	int seqhilen;
315 	__be32 *seqhi;
316 	struct page *page;
317 	struct ip_esp_hdr *esph;
318 	struct aead_request *req;
319 	struct crypto_aead *aead;
320 	struct scatterlist *sg, *dsg;
321 	int err = -ENOMEM;
322 
323 	assoclen = sizeof(struct ip_esp_hdr);
324 	seqhilen = 0;
325 
326 	if (x->props.flags & XFRM_STATE_ESN) {
327 		seqhilen += sizeof(__be32);
328 		assoclen += sizeof(__be32);
329 	}
330 
331 	aead = x->data;
332 	alen = crypto_aead_authsize(aead);
333 	ivlen = crypto_aead_ivsize(aead);
334 
335 	tmp = esp_alloc_tmp(aead, esp->nfrags + 2, seqhilen);
336 	if (!tmp)
337 		goto error;
338 
339 	seqhi = esp_tmp_seqhi(tmp);
340 	iv = esp_tmp_iv(aead, tmp, seqhilen);
341 	req = esp_tmp_req(aead, iv);
342 	sg = esp_req_sg(aead, req);
343 
344 	if (esp->inplace)
345 		dsg = sg;
346 	else
347 		dsg = &sg[esp->nfrags];
348 
349 	esph = esp_output_set_esn(skb, x, ip_esp_hdr(skb), seqhi);
350 
351 	sg_init_table(sg, esp->nfrags);
352 	err = skb_to_sgvec(skb, sg,
353 		           (unsigned char *)esph - skb->data,
354 		           assoclen + ivlen + esp->clen + alen);
355 	if (unlikely(err < 0))
356 		goto error_free;
357 
358 	if (!esp->inplace) {
359 		int allocsize;
360 		struct page_frag *pfrag = &x->xfrag;
361 
362 		allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
363 
364 		spin_lock_bh(&x->lock);
365 		if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
366 			spin_unlock_bh(&x->lock);
367 			goto error_free;
368 		}
369 
370 		skb_shinfo(skb)->nr_frags = 1;
371 
372 		page = pfrag->page;
373 		get_page(page);
374 		/* replace page frags in skb with new page */
375 		__skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
376 		pfrag->offset = pfrag->offset + allocsize;
377 		spin_unlock_bh(&x->lock);
378 
379 		sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
380 		err = skb_to_sgvec(skb, dsg,
381 			           (unsigned char *)esph - skb->data,
382 			           assoclen + ivlen + esp->clen + alen);
383 		if (unlikely(err < 0))
384 			goto error_free;
385 	}
386 
387 	if ((x->props.flags & XFRM_STATE_ESN))
388 		aead_request_set_callback(req, 0, esp_output_done_esn, skb);
389 	else
390 		aead_request_set_callback(req, 0, esp_output_done, skb);
391 
392 	aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
393 	aead_request_set_ad(req, assoclen);
394 
395 	memset(iv, 0, ivlen);
396 	memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
397 	       min(ivlen, 8));
398 
399 	ESP_SKB_CB(skb)->tmp = tmp;
400 	err = crypto_aead_encrypt(req);
401 
402 	switch (err) {
403 	case -EINPROGRESS:
404 		goto error;
405 
406 	case -ENOSPC:
407 		err = NET_XMIT_DROP;
408 		break;
409 
410 	case 0:
411 		if ((x->props.flags & XFRM_STATE_ESN))
412 			esp_output_restore_header(skb);
413 	}
414 
415 	if (sg != dsg)
416 		esp_ssg_unref(x, tmp);
417 
418 error_free:
419 	kfree(tmp);
420 error:
421 	return err;
422 }
423 EXPORT_SYMBOL_GPL(esp6_output_tail);
424 
425 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
426 {
427 	int alen;
428 	int blksize;
429 	struct ip_esp_hdr *esph;
430 	struct crypto_aead *aead;
431 	struct esp_info esp;
432 
433 	esp.inplace = true;
434 
435 	esp.proto = *skb_mac_header(skb);
436 	*skb_mac_header(skb) = IPPROTO_ESP;
437 
438 	/* skb is pure payload to encrypt */
439 
440 	aead = x->data;
441 	alen = crypto_aead_authsize(aead);
442 
443 	esp.tfclen = 0;
444 	if (x->tfcpad) {
445 		struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
446 		u32 padto;
447 
448 		padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
449 		if (skb->len < padto)
450 			esp.tfclen = padto - skb->len;
451 	}
452 	blksize = ALIGN(crypto_aead_blocksize(aead), 4);
453 	esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
454 	esp.plen = esp.clen - skb->len - esp.tfclen;
455 	esp.tailen = esp.tfclen + esp.plen + alen;
456 
457 	esp.nfrags = esp6_output_head(x, skb, &esp);
458 	if (esp.nfrags < 0)
459 		return esp.nfrags;
460 
461 	esph = ip_esp_hdr(skb);
462 	esph->spi = x->id.spi;
463 
464 	esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
465 	esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
466 			    ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
467 
468 	skb_push(skb, -skb_network_offset(skb));
469 
470 	return esp6_output_tail(x, skb, &esp);
471 }
472 
473 static inline int esp_remove_trailer(struct sk_buff *skb)
474 {
475 	struct xfrm_state *x = xfrm_input_state(skb);
476 	struct xfrm_offload *xo = xfrm_offload(skb);
477 	struct crypto_aead *aead = x->data;
478 	int alen, hlen, elen;
479 	int padlen, trimlen;
480 	__wsum csumdiff;
481 	u8 nexthdr[2];
482 	int ret;
483 
484 	alen = crypto_aead_authsize(aead);
485 	hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
486 	elen = skb->len - hlen;
487 
488 	if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) {
489 		ret = xo->proto;
490 		goto out;
491 	}
492 
493 	ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2);
494 	BUG_ON(ret);
495 
496 	ret = -EINVAL;
497 	padlen = nexthdr[0];
498 	if (padlen + 2 + alen >= elen) {
499 		net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
500 				    padlen + 2, elen - alen);
501 		goto out;
502 	}
503 
504 	trimlen = alen + padlen + 2;
505 	if (skb->ip_summed == CHECKSUM_COMPLETE) {
506 		csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
507 		skb->csum = csum_block_sub(skb->csum, csumdiff,
508 					   skb->len - trimlen);
509 	}
510 	pskb_trim(skb, skb->len - trimlen);
511 
512 	ret = nexthdr[1];
513 
514 out:
515 	return ret;
516 }
517 
518 int esp6_input_done2(struct sk_buff *skb, int err)
519 {
520 	struct xfrm_state *x = xfrm_input_state(skb);
521 	struct xfrm_offload *xo = xfrm_offload(skb);
522 	struct crypto_aead *aead = x->data;
523 	int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
524 	int hdr_len = skb_network_header_len(skb);
525 
526 	if (!xo || (xo && !(xo->flags & CRYPTO_DONE)))
527 		kfree(ESP_SKB_CB(skb)->tmp);
528 
529 	if (unlikely(err))
530 		goto out;
531 
532 	err = esp_remove_trailer(skb);
533 	if (unlikely(err < 0))
534 		goto out;
535 
536 	skb_postpull_rcsum(skb, skb_network_header(skb),
537 			   skb_network_header_len(skb));
538 	skb_pull_rcsum(skb, hlen);
539 	if (x->props.mode == XFRM_MODE_TUNNEL)
540 		skb_reset_transport_header(skb);
541 	else
542 		skb_set_transport_header(skb, -hdr_len);
543 
544 	/* RFC4303: Drop dummy packets without any error */
545 	if (err == IPPROTO_NONE)
546 		err = -EINVAL;
547 
548 out:
549 	return err;
550 }
551 EXPORT_SYMBOL_GPL(esp6_input_done2);
552 
553 static void esp_input_done(struct crypto_async_request *base, int err)
554 {
555 	struct sk_buff *skb = base->data;
556 
557 	xfrm_input_resume(skb, esp6_input_done2(skb, err));
558 }
559 
560 static void esp_input_restore_header(struct sk_buff *skb)
561 {
562 	esp_restore_header(skb, 0);
563 	__skb_pull(skb, 4);
564 }
565 
566 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
567 {
568 	struct xfrm_state *x = xfrm_input_state(skb);
569 
570 	/* For ESN we move the header forward by 4 bytes to
571 	 * accomodate the high bits.  We will move it back after
572 	 * decryption.
573 	 */
574 	if ((x->props.flags & XFRM_STATE_ESN)) {
575 		struct ip_esp_hdr *esph = skb_push(skb, 4);
576 
577 		*seqhi = esph->spi;
578 		esph->spi = esph->seq_no;
579 		esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
580 	}
581 }
582 
583 static void esp_input_done_esn(struct crypto_async_request *base, int err)
584 {
585 	struct sk_buff *skb = base->data;
586 
587 	esp_input_restore_header(skb);
588 	esp_input_done(base, err);
589 }
590 
591 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
592 {
593 	struct crypto_aead *aead = x->data;
594 	struct aead_request *req;
595 	struct sk_buff *trailer;
596 	int ivlen = crypto_aead_ivsize(aead);
597 	int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
598 	int nfrags;
599 	int assoclen;
600 	int seqhilen;
601 	int ret = 0;
602 	void *tmp;
603 	__be32 *seqhi;
604 	u8 *iv;
605 	struct scatterlist *sg;
606 
607 	if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) {
608 		ret = -EINVAL;
609 		goto out;
610 	}
611 
612 	if (elen <= 0) {
613 		ret = -EINVAL;
614 		goto out;
615 	}
616 
617 	assoclen = sizeof(struct ip_esp_hdr);
618 	seqhilen = 0;
619 
620 	if (x->props.flags & XFRM_STATE_ESN) {
621 		seqhilen += sizeof(__be32);
622 		assoclen += seqhilen;
623 	}
624 
625 	if (!skb_cloned(skb)) {
626 		if (!skb_is_nonlinear(skb)) {
627 			nfrags = 1;
628 
629 			goto skip_cow;
630 		} else if (!skb_has_frag_list(skb)) {
631 			nfrags = skb_shinfo(skb)->nr_frags;
632 			nfrags++;
633 
634 			goto skip_cow;
635 		}
636 	}
637 
638 	nfrags = skb_cow_data(skb, 0, &trailer);
639 	if (nfrags < 0) {
640 		ret = -EINVAL;
641 		goto out;
642 	}
643 
644 skip_cow:
645 	ret = -ENOMEM;
646 	tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
647 	if (!tmp)
648 		goto out;
649 
650 	ESP_SKB_CB(skb)->tmp = tmp;
651 	seqhi = esp_tmp_seqhi(tmp);
652 	iv = esp_tmp_iv(aead, tmp, seqhilen);
653 	req = esp_tmp_req(aead, iv);
654 	sg = esp_req_sg(aead, req);
655 
656 	esp_input_set_header(skb, seqhi);
657 
658 	sg_init_table(sg, nfrags);
659 	ret = skb_to_sgvec(skb, sg, 0, skb->len);
660 	if (unlikely(ret < 0)) {
661 		kfree(tmp);
662 		goto out;
663 	}
664 
665 	skb->ip_summed = CHECKSUM_NONE;
666 
667 	if ((x->props.flags & XFRM_STATE_ESN))
668 		aead_request_set_callback(req, 0, esp_input_done_esn, skb);
669 	else
670 		aead_request_set_callback(req, 0, esp_input_done, skb);
671 
672 	aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
673 	aead_request_set_ad(req, assoclen);
674 
675 	ret = crypto_aead_decrypt(req);
676 	if (ret == -EINPROGRESS)
677 		goto out;
678 
679 	if ((x->props.flags & XFRM_STATE_ESN))
680 		esp_input_restore_header(skb);
681 
682 	ret = esp6_input_done2(skb, ret);
683 
684 out:
685 	return ret;
686 }
687 
688 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
689 		    u8 type, u8 code, int offset, __be32 info)
690 {
691 	struct net *net = dev_net(skb->dev);
692 	const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
693 	struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
694 	struct xfrm_state *x;
695 
696 	if (type != ICMPV6_PKT_TOOBIG &&
697 	    type != NDISC_REDIRECT)
698 		return 0;
699 
700 	x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
701 			      esph->spi, IPPROTO_ESP, AF_INET6);
702 	if (!x)
703 		return 0;
704 
705 	if (type == NDISC_REDIRECT)
706 		ip6_redirect(skb, net, skb->dev->ifindex, 0,
707 			     sock_net_uid(net, NULL));
708 	else
709 		ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
710 	xfrm_state_put(x);
711 
712 	return 0;
713 }
714 
715 static void esp6_destroy(struct xfrm_state *x)
716 {
717 	struct crypto_aead *aead = x->data;
718 
719 	if (!aead)
720 		return;
721 
722 	crypto_free_aead(aead);
723 }
724 
725 static int esp_init_aead(struct xfrm_state *x)
726 {
727 	char aead_name[CRYPTO_MAX_ALG_NAME];
728 	struct crypto_aead *aead;
729 	int err;
730 
731 	err = -ENAMETOOLONG;
732 	if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
733 		     x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
734 		goto error;
735 
736 	aead = crypto_alloc_aead(aead_name, 0, 0);
737 	err = PTR_ERR(aead);
738 	if (IS_ERR(aead))
739 		goto error;
740 
741 	x->data = aead;
742 
743 	err = crypto_aead_setkey(aead, x->aead->alg_key,
744 				 (x->aead->alg_key_len + 7) / 8);
745 	if (err)
746 		goto error;
747 
748 	err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
749 	if (err)
750 		goto error;
751 
752 error:
753 	return err;
754 }
755 
756 static int esp_init_authenc(struct xfrm_state *x)
757 {
758 	struct crypto_aead *aead;
759 	struct crypto_authenc_key_param *param;
760 	struct rtattr *rta;
761 	char *key;
762 	char *p;
763 	char authenc_name[CRYPTO_MAX_ALG_NAME];
764 	unsigned int keylen;
765 	int err;
766 
767 	err = -EINVAL;
768 	if (!x->ealg)
769 		goto error;
770 
771 	err = -ENAMETOOLONG;
772 
773 	if ((x->props.flags & XFRM_STATE_ESN)) {
774 		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
775 			     "%s%sauthencesn(%s,%s)%s",
776 			     x->geniv ?: "", x->geniv ? "(" : "",
777 			     x->aalg ? x->aalg->alg_name : "digest_null",
778 			     x->ealg->alg_name,
779 			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
780 			goto error;
781 	} else {
782 		if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
783 			     "%s%sauthenc(%s,%s)%s",
784 			     x->geniv ?: "", x->geniv ? "(" : "",
785 			     x->aalg ? x->aalg->alg_name : "digest_null",
786 			     x->ealg->alg_name,
787 			     x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
788 			goto error;
789 	}
790 
791 	aead = crypto_alloc_aead(authenc_name, 0, 0);
792 	err = PTR_ERR(aead);
793 	if (IS_ERR(aead))
794 		goto error;
795 
796 	x->data = aead;
797 
798 	keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
799 		 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
800 	err = -ENOMEM;
801 	key = kmalloc(keylen, GFP_KERNEL);
802 	if (!key)
803 		goto error;
804 
805 	p = key;
806 	rta = (void *)p;
807 	rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
808 	rta->rta_len = RTA_LENGTH(sizeof(*param));
809 	param = RTA_DATA(rta);
810 	p += RTA_SPACE(sizeof(*param));
811 
812 	if (x->aalg) {
813 		struct xfrm_algo_desc *aalg_desc;
814 
815 		memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
816 		p += (x->aalg->alg_key_len + 7) / 8;
817 
818 		aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
819 		BUG_ON(!aalg_desc);
820 
821 		err = -EINVAL;
822 		if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
823 		    crypto_aead_authsize(aead)) {
824 			pr_info("ESP: %s digestsize %u != %hu\n",
825 				x->aalg->alg_name,
826 				crypto_aead_authsize(aead),
827 				aalg_desc->uinfo.auth.icv_fullbits / 8);
828 			goto free_key;
829 		}
830 
831 		err = crypto_aead_setauthsize(
832 			aead, x->aalg->alg_trunc_len / 8);
833 		if (err)
834 			goto free_key;
835 	}
836 
837 	param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
838 	memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
839 
840 	err = crypto_aead_setkey(aead, key, keylen);
841 
842 free_key:
843 	kfree(key);
844 
845 error:
846 	return err;
847 }
848 
849 static int esp6_init_state(struct xfrm_state *x)
850 {
851 	struct crypto_aead *aead;
852 	u32 align;
853 	int err;
854 
855 	if (x->encap)
856 		return -EINVAL;
857 
858 	x->data = NULL;
859 
860 	if (x->aead)
861 		err = esp_init_aead(x);
862 	else
863 		err = esp_init_authenc(x);
864 
865 	if (err)
866 		goto error;
867 
868 	aead = x->data;
869 
870 	x->props.header_len = sizeof(struct ip_esp_hdr) +
871 			      crypto_aead_ivsize(aead);
872 	switch (x->props.mode) {
873 	case XFRM_MODE_BEET:
874 		if (x->sel.family != AF_INET6)
875 			x->props.header_len += IPV4_BEET_PHMAXLEN +
876 					       (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
877 		break;
878 	default:
879 	case XFRM_MODE_TRANSPORT:
880 		break;
881 	case XFRM_MODE_TUNNEL:
882 		x->props.header_len += sizeof(struct ipv6hdr);
883 		break;
884 	}
885 
886 	align = ALIGN(crypto_aead_blocksize(aead), 4);
887 	x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
888 
889 error:
890 	return err;
891 }
892 
893 static int esp6_rcv_cb(struct sk_buff *skb, int err)
894 {
895 	return 0;
896 }
897 
898 static const struct xfrm_type esp6_type = {
899 	.description	= "ESP6",
900 	.owner		= THIS_MODULE,
901 	.proto		= IPPROTO_ESP,
902 	.flags		= XFRM_TYPE_REPLAY_PROT,
903 	.init_state	= esp6_init_state,
904 	.destructor	= esp6_destroy,
905 	.input		= esp6_input,
906 	.output		= esp6_output,
907 	.hdr_offset	= xfrm6_find_1stfragopt,
908 };
909 
910 static struct xfrm6_protocol esp6_protocol = {
911 	.handler	=	xfrm6_rcv,
912 	.cb_handler	=	esp6_rcv_cb,
913 	.err_handler	=	esp6_err,
914 	.priority	=	0,
915 };
916 
917 static int __init esp6_init(void)
918 {
919 	if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
920 		pr_info("%s: can't add xfrm type\n", __func__);
921 		return -EAGAIN;
922 	}
923 	if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) {
924 		pr_info("%s: can't add protocol\n", __func__);
925 		xfrm_unregister_type(&esp6_type, AF_INET6);
926 		return -EAGAIN;
927 	}
928 
929 	return 0;
930 }
931 
932 static void __exit esp6_fini(void)
933 {
934 	if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0)
935 		pr_info("%s: can't remove protocol\n", __func__);
936 	xfrm_unregister_type(&esp6_type, AF_INET6);
937 }
938 
939 module_init(esp6_init);
940 module_exit(esp6_fini);
941 
942 MODULE_LICENSE("GPL");
943 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
944