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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_checksum.h>
30 #include <net/ip6_route.h>
31 #include <net/icmp.h>
32 #include <net/ipv6.h>
33 #include <net/protocol.h>
34 #include <net/udp.h>
35 #include <linux/icmpv6.h>
36 #include <net/tcp.h>
37 #include <net/espintcp.h>
38 #include <net/inet6_hashtables.h>
39
40 #include <linux/highmem.h>
41
42 struct esp_skb_cb {
43 struct xfrm_skb_cb xfrm;
44 void *tmp;
45 };
46
47 struct esp_output_extra {
48 __be32 seqhi;
49 u32 esphoff;
50 };
51
52 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
53
54 /*
55 * Allocate an AEAD request structure with extra space for SG and IV.
56 *
57 * For alignment considerations the upper 32 bits of the sequence number are
58 * placed at the front, if present. Followed by the IV, the request and finally
59 * the SG list.
60 *
61 * TODO: Use spare space in skb for this where possible.
62 */
63 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
64 {
65 unsigned int len;
66
67 len = seqihlen;
68
69 len += crypto_aead_ivsize(aead);
70
71 if (len) {
72 len += crypto_aead_alignmask(aead) &
73 ~(crypto_tfm_ctx_alignment() - 1);
74 len = ALIGN(len, crypto_tfm_ctx_alignment());
75 }
76
77 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
78 len = ALIGN(len, __alignof__(struct scatterlist));
79
80 len += sizeof(struct scatterlist) * nfrags;
81
82 return kmalloc(len, GFP_ATOMIC);
83 }
84
85 static inline void *esp_tmp_extra(void *tmp)
86 {
87 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
88 }
89
90 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
91 {
92 return crypto_aead_ivsize(aead) ?
93 PTR_ALIGN((u8 *)tmp + seqhilen,
94 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
95 }
96
97 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
98 {
99 struct aead_request *req;
100
101 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
102 crypto_tfm_ctx_alignment());
103 aead_request_set_tfm(req, aead);
104 return req;
105 }
106
107 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
108 struct aead_request *req)
109 {
110 return (void *)ALIGN((unsigned long)(req + 1) +
111 crypto_aead_reqsize(aead),
112 __alignof__(struct scatterlist));
113 }
114
115 static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
116 {
117 struct esp_output_extra *extra = esp_tmp_extra(tmp);
118 struct crypto_aead *aead = x->data;
119 int extralen = 0;
120 u8 *iv;
121 struct aead_request *req;
122 struct scatterlist *sg;
123
124 if (x->props.flags & XFRM_STATE_ESN)
125 extralen += sizeof(*extra);
126
127 iv = esp_tmp_iv(aead, tmp, extralen);
128 req = esp_tmp_req(aead, iv);
129
130 /* Unref skb_frag_pages in the src scatterlist if necessary.
131 * Skip the first sg which comes from skb->data.
132 */
133 if (req->src != req->dst)
134 for (sg = sg_next(req->src); sg; sg = sg_next(sg))
135 put_page(sg_page(sg));
136 }
137
138 #ifdef CONFIG_INET6_ESPINTCP
139 struct esp_tcp_sk {
140 struct sock *sk;
141 struct rcu_head rcu;
142 };
143
144 static void esp_free_tcp_sk(struct rcu_head *head)
145 {
146 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu);
147
148 sock_put(esk->sk);
149 kfree(esk);
150 }
151
152 static struct sock *esp6_find_tcp_sk(struct xfrm_state *x)
153 {
154 struct xfrm_encap_tmpl *encap = x->encap;
155 struct esp_tcp_sk *esk;
156 __be16 sport, dport;
157 struct sock *nsk;
158 struct sock *sk;
159
160 sk = rcu_dereference(x->encap_sk);
161 if (sk && sk->sk_state == TCP_ESTABLISHED)
162 return sk;
163
164 spin_lock_bh(&x->lock);
165 sport = encap->encap_sport;
166 dport = encap->encap_dport;
167 nsk = rcu_dereference_protected(x->encap_sk,
168 lockdep_is_held(&x->lock));
169 if (sk && sk == nsk) {
170 esk = kmalloc(sizeof(*esk), GFP_ATOMIC);
171 if (!esk) {
172 spin_unlock_bh(&x->lock);
173 return ERR_PTR(-ENOMEM);
174 }
175 RCU_INIT_POINTER(x->encap_sk, NULL);
176 esk->sk = sk;
177 call_rcu(&esk->rcu, esp_free_tcp_sk);
178 }
179 spin_unlock_bh(&x->lock);
180
181 sk = __inet6_lookup_established(xs_net(x), &tcp_hashinfo, &x->id.daddr.in6,
182 dport, &x->props.saddr.in6, ntohs(sport), 0, 0);
183 if (!sk)
184 return ERR_PTR(-ENOENT);
185
186 if (!tcp_is_ulp_esp(sk)) {
187 sock_put(sk);
188 return ERR_PTR(-EINVAL);
189 }
190
191 spin_lock_bh(&x->lock);
192 nsk = rcu_dereference_protected(x->encap_sk,
193 lockdep_is_held(&x->lock));
194 if (encap->encap_sport != sport ||
195 encap->encap_dport != dport) {
196 sock_put(sk);
197 sk = nsk ?: ERR_PTR(-EREMCHG);
198 } else if (sk == nsk) {
199 sock_put(sk);
200 } else {
201 rcu_assign_pointer(x->encap_sk, sk);
202 }
203 spin_unlock_bh(&x->lock);
204
205 return sk;
206 }
207
208 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
209 {
210 struct sock *sk;
211 int err;
212
213 rcu_read_lock();
214
215 sk = esp6_find_tcp_sk(x);
216 err = PTR_ERR_OR_ZERO(sk);
217 if (err)
218 goto out;
219
220 bh_lock_sock(sk);
221 if (sock_owned_by_user(sk))
222 err = espintcp_queue_out(sk, skb);
223 else
224 err = espintcp_push_skb(sk, skb);
225 bh_unlock_sock(sk);
226
227 out:
228 rcu_read_unlock();
229 return err;
230 }
231
232 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
233 struct sk_buff *skb)
234 {
235 struct dst_entry *dst = skb_dst(skb);
236 struct xfrm_state *x = dst->xfrm;
237
238 return esp_output_tcp_finish(x, skb);
239 }
240
241 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
242 {
243 int err;
244
245 local_bh_disable();
246 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
247 local_bh_enable();
248
249 /* EINPROGRESS just happens to do the right thing. It
250 * actually means that the skb has been consumed and
251 * isn't coming back.
252 */
253 return err ?: -EINPROGRESS;
254 }
255 #else
256 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
257 {
258 kfree_skb(skb);
259
260 return -EOPNOTSUPP;
261 }
262 #endif
263
264 static void esp_output_encap_csum(struct sk_buff *skb)
265 {
266 /* UDP encap with IPv6 requires a valid checksum */
267 if (*skb_mac_header(skb) == IPPROTO_UDP) {
268 struct udphdr *uh = udp_hdr(skb);
269 struct ipv6hdr *ip6h = ipv6_hdr(skb);
270 int len = ntohs(uh->len);
271 unsigned int offset = skb_transport_offset(skb);
272 __wsum csum = skb_checksum(skb, offset, skb->len - offset, 0);
273
274 uh->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
275 len, IPPROTO_UDP, csum);
276 if (uh->check == 0)
277 uh->check = CSUM_MANGLED_0;
278 }
279 }
280
281 static void esp_output_done(struct crypto_async_request *base, int err)
282 {
283 struct sk_buff *skb = base->data;
284 struct xfrm_offload *xo = xfrm_offload(skb);
285 void *tmp;
286 struct xfrm_state *x;
287
288 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
289 struct sec_path *sp = skb_sec_path(skb);
290
291 x = sp->xvec[sp->len - 1];
292 } else {
293 x = skb_dst(skb)->xfrm;
294 }
295
296 tmp = ESP_SKB_CB(skb)->tmp;
297 esp_ssg_unref(x, tmp);
298 kfree(tmp);
299
300 esp_output_encap_csum(skb);
301
302 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
303 if (err) {
304 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
305 kfree_skb(skb);
306 return;
307 }
308
309 skb_push(skb, skb->data - skb_mac_header(skb));
310 secpath_reset(skb);
311 xfrm_dev_resume(skb);
312 } else {
313 if (!err &&
314 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
315 esp_output_tail_tcp(x, skb);
316 else
317 xfrm_output_resume(skb->sk, skb, err);
318 }
319 }
320
321 /* Move ESP header back into place. */
322 static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
323 {
324 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
325 void *tmp = ESP_SKB_CB(skb)->tmp;
326 __be32 *seqhi = esp_tmp_extra(tmp);
327
328 esph->seq_no = esph->spi;
329 esph->spi = *seqhi;
330 }
331
332 static void esp_output_restore_header(struct sk_buff *skb)
333 {
334 void *tmp = ESP_SKB_CB(skb)->tmp;
335 struct esp_output_extra *extra = esp_tmp_extra(tmp);
336
337 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
338 sizeof(__be32));
339 }
340
341 static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb,
342 struct xfrm_state *x,
343 struct ip_esp_hdr *esph,
344 struct esp_output_extra *extra)
345 {
346 /* For ESN we move the header forward by 4 bytes to
347 * accomodate the high bits. We will move it back after
348 * encryption.
349 */
350 if ((x->props.flags & XFRM_STATE_ESN)) {
351 __u32 seqhi;
352 struct xfrm_offload *xo = xfrm_offload(skb);
353
354 if (xo)
355 seqhi = xo->seq.hi;
356 else
357 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
358
359 extra->esphoff = (unsigned char *)esph -
360 skb_transport_header(skb);
361 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
362 extra->seqhi = esph->spi;
363 esph->seq_no = htonl(seqhi);
364 }
365
366 esph->spi = x->id.spi;
367
368 return esph;
369 }
370
371 static void esp_output_done_esn(struct crypto_async_request *base, int err)
372 {
373 struct sk_buff *skb = base->data;
374
375 esp_output_restore_header(skb);
376 esp_output_done(base, err);
377 }
378
379 static struct ip_esp_hdr *esp6_output_udp_encap(struct sk_buff *skb,
380 int encap_type,
381 struct esp_info *esp,
382 __be16 sport,
383 __be16 dport)
384 {
385 struct udphdr *uh;
386 __be32 *udpdata32;
387 unsigned int len;
388
389 len = skb->len + esp->tailen - skb_transport_offset(skb);
390 if (len > U16_MAX)
391 return ERR_PTR(-EMSGSIZE);
392
393 uh = (struct udphdr *)esp->esph;
394 uh->source = sport;
395 uh->dest = dport;
396 uh->len = htons(len);
397 uh->check = 0;
398
399 *skb_mac_header(skb) = IPPROTO_UDP;
400
401 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
402 udpdata32 = (__be32 *)(uh + 1);
403 udpdata32[0] = udpdata32[1] = 0;
404 return (struct ip_esp_hdr *)(udpdata32 + 2);
405 }
406
407 return (struct ip_esp_hdr *)(uh + 1);
408 }
409
410 #ifdef CONFIG_INET6_ESPINTCP
411 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x,
412 struct sk_buff *skb,
413 struct esp_info *esp)
414 {
415 __be16 *lenp = (void *)esp->esph;
416 struct ip_esp_hdr *esph;
417 unsigned int len;
418 struct sock *sk;
419
420 len = skb->len + esp->tailen - skb_transport_offset(skb);
421 if (len > IP_MAX_MTU)
422 return ERR_PTR(-EMSGSIZE);
423
424 rcu_read_lock();
425 sk = esp6_find_tcp_sk(x);
426 rcu_read_unlock();
427
428 if (IS_ERR(sk))
429 return ERR_CAST(sk);
430
431 *lenp = htons(len);
432 esph = (struct ip_esp_hdr *)(lenp + 1);
433
434 return esph;
435 }
436 #else
437 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x,
438 struct sk_buff *skb,
439 struct esp_info *esp)
440 {
441 return ERR_PTR(-EOPNOTSUPP);
442 }
443 #endif
444
445 static int esp6_output_encap(struct xfrm_state *x, struct sk_buff *skb,
446 struct esp_info *esp)
447 {
448 struct xfrm_encap_tmpl *encap = x->encap;
449 struct ip_esp_hdr *esph;
450 __be16 sport, dport;
451 int encap_type;
452
453 spin_lock_bh(&x->lock);
454 sport = encap->encap_sport;
455 dport = encap->encap_dport;
456 encap_type = encap->encap_type;
457 spin_unlock_bh(&x->lock);
458
459 switch (encap_type) {
460 default:
461 case UDP_ENCAP_ESPINUDP:
462 case UDP_ENCAP_ESPINUDP_NON_IKE:
463 esph = esp6_output_udp_encap(skb, encap_type, esp, sport, dport);
464 break;
465 case TCP_ENCAP_ESPINTCP:
466 esph = esp6_output_tcp_encap(x, skb, esp);
467 break;
468 }
469
470 if (IS_ERR(esph))
471 return PTR_ERR(esph);
472
473 esp->esph = esph;
474
475 return 0;
476 }
477
478 int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
479 {
480 u8 *tail;
481 int nfrags;
482 int esph_offset;
483 struct page *page;
484 struct sk_buff *trailer;
485 int tailen = esp->tailen;
486
487 if (x->encap) {
488 int err = esp6_output_encap(x, skb, esp);
489
490 if (err < 0)
491 return err;
492 }
493
494 if (!skb_cloned(skb)) {
495 if (tailen <= skb_tailroom(skb)) {
496 nfrags = 1;
497 trailer = skb;
498 tail = skb_tail_pointer(trailer);
499
500 goto skip_cow;
501 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
502 && !skb_has_frag_list(skb)) {
503 int allocsize;
504 struct sock *sk = skb->sk;
505 struct page_frag *pfrag = &x->xfrag;
506
507 esp->inplace = false;
508
509 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
510
511 spin_lock_bh(&x->lock);
512
513 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
514 spin_unlock_bh(&x->lock);
515 goto cow;
516 }
517
518 page = pfrag->page;
519 get_page(page);
520
521 tail = page_address(page) + pfrag->offset;
522
523 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
524
525 nfrags = skb_shinfo(skb)->nr_frags;
526
527 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
528 tailen);
529 skb_shinfo(skb)->nr_frags = ++nfrags;
530
531 pfrag->offset = pfrag->offset + allocsize;
532
533 spin_unlock_bh(&x->lock);
534
535 nfrags++;
536
537 skb->len += tailen;
538 skb->data_len += tailen;
539 skb->truesize += tailen;
540 if (sk && sk_fullsock(sk))
541 refcount_add(tailen, &sk->sk_wmem_alloc);
542
543 goto out;
544 }
545 }
546
547 cow:
548 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
549
550 nfrags = skb_cow_data(skb, tailen, &trailer);
551 if (nfrags < 0)
552 goto out;
553 tail = skb_tail_pointer(trailer);
554 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
555
556 skip_cow:
557 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
558 pskb_put(skb, trailer, tailen);
559
560 out:
561 return nfrags;
562 }
563 EXPORT_SYMBOL_GPL(esp6_output_head);
564
565 int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
566 {
567 u8 *iv;
568 int alen;
569 void *tmp;
570 int ivlen;
571 int assoclen;
572 int extralen;
573 struct page *page;
574 struct ip_esp_hdr *esph;
575 struct aead_request *req;
576 struct crypto_aead *aead;
577 struct scatterlist *sg, *dsg;
578 struct esp_output_extra *extra;
579 int err = -ENOMEM;
580
581 assoclen = sizeof(struct ip_esp_hdr);
582 extralen = 0;
583
584 if (x->props.flags & XFRM_STATE_ESN) {
585 extralen += sizeof(*extra);
586 assoclen += sizeof(__be32);
587 }
588
589 aead = x->data;
590 alen = crypto_aead_authsize(aead);
591 ivlen = crypto_aead_ivsize(aead);
592
593 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
594 if (!tmp)
595 goto error;
596
597 extra = esp_tmp_extra(tmp);
598 iv = esp_tmp_iv(aead, tmp, extralen);
599 req = esp_tmp_req(aead, iv);
600 sg = esp_req_sg(aead, req);
601
602 if (esp->inplace)
603 dsg = sg;
604 else
605 dsg = &sg[esp->nfrags];
606
607 esph = esp_output_set_esn(skb, x, esp->esph, extra);
608 esp->esph = esph;
609
610 sg_init_table(sg, esp->nfrags);
611 err = skb_to_sgvec(skb, sg,
612 (unsigned char *)esph - skb->data,
613 assoclen + ivlen + esp->clen + alen);
614 if (unlikely(err < 0))
615 goto error_free;
616
617 if (!esp->inplace) {
618 int allocsize;
619 struct page_frag *pfrag = &x->xfrag;
620
621 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
622
623 spin_lock_bh(&x->lock);
624 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
625 spin_unlock_bh(&x->lock);
626 goto error_free;
627 }
628
629 skb_shinfo(skb)->nr_frags = 1;
630
631 page = pfrag->page;
632 get_page(page);
633 /* replace page frags in skb with new page */
634 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
635 pfrag->offset = pfrag->offset + allocsize;
636 spin_unlock_bh(&x->lock);
637
638 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
639 err = skb_to_sgvec(skb, dsg,
640 (unsigned char *)esph - skb->data,
641 assoclen + ivlen + esp->clen + alen);
642 if (unlikely(err < 0))
643 goto error_free;
644 }
645
646 if ((x->props.flags & XFRM_STATE_ESN))
647 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
648 else
649 aead_request_set_callback(req, 0, esp_output_done, skb);
650
651 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
652 aead_request_set_ad(req, assoclen);
653
654 memset(iv, 0, ivlen);
655 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
656 min(ivlen, 8));
657
658 ESP_SKB_CB(skb)->tmp = tmp;
659 err = crypto_aead_encrypt(req);
660
661 switch (err) {
662 case -EINPROGRESS:
663 goto error;
664
665 case -ENOSPC:
666 err = NET_XMIT_DROP;
667 break;
668
669 case 0:
670 if ((x->props.flags & XFRM_STATE_ESN))
671 esp_output_restore_header(skb);
672 esp_output_encap_csum(skb);
673 }
674
675 if (sg != dsg)
676 esp_ssg_unref(x, tmp);
677
678 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
679 err = esp_output_tail_tcp(x, skb);
680
681 error_free:
682 kfree(tmp);
683 error:
684 return err;
685 }
686 EXPORT_SYMBOL_GPL(esp6_output_tail);
687
688 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
689 {
690 int alen;
691 int blksize;
692 struct ip_esp_hdr *esph;
693 struct crypto_aead *aead;
694 struct esp_info esp;
695
696 esp.inplace = true;
697
698 esp.proto = *skb_mac_header(skb);
699 *skb_mac_header(skb) = IPPROTO_ESP;
700
701 /* skb is pure payload to encrypt */
702
703 aead = x->data;
704 alen = crypto_aead_authsize(aead);
705
706 esp.tfclen = 0;
707 if (x->tfcpad) {
708 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
709 u32 padto;
710
711 padto = min(x->tfcpad, __xfrm_state_mtu(x, dst->child_mtu_cached));
712 if (skb->len < padto)
713 esp.tfclen = padto - skb->len;
714 }
715 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
716 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
717 esp.plen = esp.clen - skb->len - esp.tfclen;
718 esp.tailen = esp.tfclen + esp.plen + alen;
719
720 esp.esph = ip_esp_hdr(skb);
721
722 esp.nfrags = esp6_output_head(x, skb, &esp);
723 if (esp.nfrags < 0)
724 return esp.nfrags;
725
726 esph = esp.esph;
727 esph->spi = x->id.spi;
728
729 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
730 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
731 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
732
733 skb_push(skb, -skb_network_offset(skb));
734
735 return esp6_output_tail(x, skb, &esp);
736 }
737
738 static inline int esp_remove_trailer(struct sk_buff *skb)
739 {
740 struct xfrm_state *x = xfrm_input_state(skb);
741 struct xfrm_offload *xo = xfrm_offload(skb);
742 struct crypto_aead *aead = x->data;
743 int alen, hlen, elen;
744 int padlen, trimlen;
745 __wsum csumdiff;
746 u8 nexthdr[2];
747 int ret;
748
749 alen = crypto_aead_authsize(aead);
750 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
751 elen = skb->len - hlen;
752
753 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) {
754 ret = xo->proto;
755 goto out;
756 }
757
758 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2);
759 BUG_ON(ret);
760
761 ret = -EINVAL;
762 padlen = nexthdr[0];
763 if (padlen + 2 + alen >= elen) {
764 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
765 padlen + 2, elen - alen);
766 goto out;
767 }
768
769 trimlen = alen + padlen + 2;
770 if (skb->ip_summed == CHECKSUM_COMPLETE) {
771 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
772 skb->csum = csum_block_sub(skb->csum, csumdiff,
773 skb->len - trimlen);
774 }
775 pskb_trim(skb, skb->len - trimlen);
776
777 ret = nexthdr[1];
778
779 out:
780 return ret;
781 }
782
783 int esp6_input_done2(struct sk_buff *skb, int err)
784 {
785 struct xfrm_state *x = xfrm_input_state(skb);
786 struct xfrm_offload *xo = xfrm_offload(skb);
787 struct crypto_aead *aead = x->data;
788 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
789 int hdr_len = skb_network_header_len(skb);
790
791 if (!xo || !(xo->flags & CRYPTO_DONE))
792 kfree(ESP_SKB_CB(skb)->tmp);
793
794 if (unlikely(err))
795 goto out;
796
797 err = esp_remove_trailer(skb);
798 if (unlikely(err < 0))
799 goto out;
800
801 if (x->encap) {
802 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
803 int offset = skb_network_offset(skb) + sizeof(*ip6h);
804 struct xfrm_encap_tmpl *encap = x->encap;
805 u8 nexthdr = ip6h->nexthdr;
806 __be16 frag_off, source;
807 struct udphdr *uh;
808 struct tcphdr *th;
809
810 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
811
812 if (offset < 0) {
813 err = -EINVAL;
814 goto out;
815 }
816
817 uh = (void *)(skb->data + offset);
818 th = (void *)(skb->data + offset);
819 hdr_len += offset;
820
821 switch (x->encap->encap_type) {
822 case TCP_ENCAP_ESPINTCP:
823 source = th->source;
824 break;
825 case UDP_ENCAP_ESPINUDP:
826 case UDP_ENCAP_ESPINUDP_NON_IKE:
827 source = uh->source;
828 break;
829 default:
830 WARN_ON_ONCE(1);
831 err = -EINVAL;
832 goto out;
833 }
834
835 /*
836 * 1) if the NAT-T peer's IP or port changed then
837 * advertize the change to the keying daemon.
838 * This is an inbound SA, so just compare
839 * SRC ports.
840 */
841 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) ||
842 source != encap->encap_sport) {
843 xfrm_address_t ipaddr;
844
845 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6));
846 km_new_mapping(x, &ipaddr, source);
847
848 /* XXX: perhaps add an extra
849 * policy check here, to see
850 * if we should allow or
851 * reject a packet from a
852 * different source
853 * address/port.
854 */
855 }
856
857 /*
858 * 2) ignore UDP/TCP checksums in case
859 * of NAT-T in Transport Mode, or
860 * perform other post-processing fixes
861 * as per draft-ietf-ipsec-udp-encaps-06,
862 * section 3.1.2
863 */
864 if (x->props.mode == XFRM_MODE_TRANSPORT)
865 skb->ip_summed = CHECKSUM_UNNECESSARY;
866 }
867
868 skb_postpull_rcsum(skb, skb_network_header(skb),
869 skb_network_header_len(skb));
870 skb_pull_rcsum(skb, hlen);
871 if (x->props.mode == XFRM_MODE_TUNNEL)
872 skb_reset_transport_header(skb);
873 else
874 skb_set_transport_header(skb, -hdr_len);
875
876 /* RFC4303: Drop dummy packets without any error */
877 if (err == IPPROTO_NONE)
878 err = -EINVAL;
879
880 out:
881 return err;
882 }
883 EXPORT_SYMBOL_GPL(esp6_input_done2);
884
885 static void esp_input_done(struct crypto_async_request *base, int err)
886 {
887 struct sk_buff *skb = base->data;
888
889 xfrm_input_resume(skb, esp6_input_done2(skb, err));
890 }
891
892 static void esp_input_restore_header(struct sk_buff *skb)
893 {
894 esp_restore_header(skb, 0);
895 __skb_pull(skb, 4);
896 }
897
898 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
899 {
900 struct xfrm_state *x = xfrm_input_state(skb);
901
902 /* For ESN we move the header forward by 4 bytes to
903 * accomodate the high bits. We will move it back after
904 * decryption.
905 */
906 if ((x->props.flags & XFRM_STATE_ESN)) {
907 struct ip_esp_hdr *esph = skb_push(skb, 4);
908
909 *seqhi = esph->spi;
910 esph->spi = esph->seq_no;
911 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
912 }
913 }
914
915 static void esp_input_done_esn(struct crypto_async_request *base, int err)
916 {
917 struct sk_buff *skb = base->data;
918
919 esp_input_restore_header(skb);
920 esp_input_done(base, err);
921 }
922
923 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
924 {
925 struct crypto_aead *aead = x->data;
926 struct aead_request *req;
927 struct sk_buff *trailer;
928 int ivlen = crypto_aead_ivsize(aead);
929 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
930 int nfrags;
931 int assoclen;
932 int seqhilen;
933 int ret = 0;
934 void *tmp;
935 __be32 *seqhi;
936 u8 *iv;
937 struct scatterlist *sg;
938
939 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) {
940 ret = -EINVAL;
941 goto out;
942 }
943
944 if (elen <= 0) {
945 ret = -EINVAL;
946 goto out;
947 }
948
949 assoclen = sizeof(struct ip_esp_hdr);
950 seqhilen = 0;
951
952 if (x->props.flags & XFRM_STATE_ESN) {
953 seqhilen += sizeof(__be32);
954 assoclen += seqhilen;
955 }
956
957 if (!skb_cloned(skb)) {
958 if (!skb_is_nonlinear(skb)) {
959 nfrags = 1;
960
961 goto skip_cow;
962 } else if (!skb_has_frag_list(skb)) {
963 nfrags = skb_shinfo(skb)->nr_frags;
964 nfrags++;
965
966 goto skip_cow;
967 }
968 }
969
970 nfrags = skb_cow_data(skb, 0, &trailer);
971 if (nfrags < 0) {
972 ret = -EINVAL;
973 goto out;
974 }
975
976 skip_cow:
977 ret = -ENOMEM;
978 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
979 if (!tmp)
980 goto out;
981
982 ESP_SKB_CB(skb)->tmp = tmp;
983 seqhi = esp_tmp_extra(tmp);
984 iv = esp_tmp_iv(aead, tmp, seqhilen);
985 req = esp_tmp_req(aead, iv);
986 sg = esp_req_sg(aead, req);
987
988 esp_input_set_header(skb, seqhi);
989
990 sg_init_table(sg, nfrags);
991 ret = skb_to_sgvec(skb, sg, 0, skb->len);
992 if (unlikely(ret < 0)) {
993 kfree(tmp);
994 goto out;
995 }
996
997 skb->ip_summed = CHECKSUM_NONE;
998
999 if ((x->props.flags & XFRM_STATE_ESN))
1000 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
1001 else
1002 aead_request_set_callback(req, 0, esp_input_done, skb);
1003
1004 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
1005 aead_request_set_ad(req, assoclen);
1006
1007 ret = crypto_aead_decrypt(req);
1008 if (ret == -EINPROGRESS)
1009 goto out;
1010
1011 if ((x->props.flags & XFRM_STATE_ESN))
1012 esp_input_restore_header(skb);
1013
1014 ret = esp6_input_done2(skb, ret);
1015
1016 out:
1017 return ret;
1018 }
1019
1020 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
1021 u8 type, u8 code, int offset, __be32 info)
1022 {
1023 struct net *net = dev_net(skb->dev);
1024 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
1025 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
1026 struct xfrm_state *x;
1027
1028 if (type != ICMPV6_PKT_TOOBIG &&
1029 type != NDISC_REDIRECT)
1030 return 0;
1031
1032 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
1033 esph->spi, IPPROTO_ESP, AF_INET6);
1034 if (!x)
1035 return 0;
1036
1037 if (type == NDISC_REDIRECT)
1038 ip6_redirect(skb, net, skb->dev->ifindex, 0,
1039 sock_net_uid(net, NULL));
1040 else
1041 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
1042 xfrm_state_put(x);
1043
1044 return 0;
1045 }
1046
1047 static void esp6_destroy(struct xfrm_state *x)
1048 {
1049 struct crypto_aead *aead = x->data;
1050
1051 if (!aead)
1052 return;
1053
1054 crypto_free_aead(aead);
1055 }
1056
1057 static int esp_init_aead(struct xfrm_state *x)
1058 {
1059 char aead_name[CRYPTO_MAX_ALG_NAME];
1060 struct crypto_aead *aead;
1061 int err;
1062
1063 err = -ENAMETOOLONG;
1064 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1065 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
1066 goto error;
1067
1068 aead = crypto_alloc_aead(aead_name, 0, 0);
1069 err = PTR_ERR(aead);
1070 if (IS_ERR(aead))
1071 goto error;
1072
1073 x->data = aead;
1074
1075 err = crypto_aead_setkey(aead, x->aead->alg_key,
1076 (x->aead->alg_key_len + 7) / 8);
1077 if (err)
1078 goto error;
1079
1080 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1081 if (err)
1082 goto error;
1083
1084 error:
1085 return err;
1086 }
1087
1088 static int esp_init_authenc(struct xfrm_state *x)
1089 {
1090 struct crypto_aead *aead;
1091 struct crypto_authenc_key_param *param;
1092 struct rtattr *rta;
1093 char *key;
1094 char *p;
1095 char authenc_name[CRYPTO_MAX_ALG_NAME];
1096 unsigned int keylen;
1097 int err;
1098
1099 err = -EINVAL;
1100 if (!x->ealg)
1101 goto error;
1102
1103 err = -ENAMETOOLONG;
1104
1105 if ((x->props.flags & XFRM_STATE_ESN)) {
1106 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1107 "%s%sauthencesn(%s,%s)%s",
1108 x->geniv ?: "", x->geniv ? "(" : "",
1109 x->aalg ? x->aalg->alg_name : "digest_null",
1110 x->ealg->alg_name,
1111 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
1112 goto error;
1113 } else {
1114 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1115 "%s%sauthenc(%s,%s)%s",
1116 x->geniv ?: "", x->geniv ? "(" : "",
1117 x->aalg ? x->aalg->alg_name : "digest_null",
1118 x->ealg->alg_name,
1119 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
1120 goto error;
1121 }
1122
1123 aead = crypto_alloc_aead(authenc_name, 0, 0);
1124 err = PTR_ERR(aead);
1125 if (IS_ERR(aead))
1126 goto error;
1127
1128 x->data = aead;
1129
1130 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1131 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1132 err = -ENOMEM;
1133 key = kmalloc(keylen, GFP_KERNEL);
1134 if (!key)
1135 goto error;
1136
1137 p = key;
1138 rta = (void *)p;
1139 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1140 rta->rta_len = RTA_LENGTH(sizeof(*param));
1141 param = RTA_DATA(rta);
1142 p += RTA_SPACE(sizeof(*param));
1143
1144 if (x->aalg) {
1145 struct xfrm_algo_desc *aalg_desc;
1146
1147 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1148 p += (x->aalg->alg_key_len + 7) / 8;
1149
1150 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1151 BUG_ON(!aalg_desc);
1152
1153 err = -EINVAL;
1154 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1155 crypto_aead_authsize(aead)) {
1156 pr_info("ESP: %s digestsize %u != %u\n",
1157 x->aalg->alg_name,
1158 crypto_aead_authsize(aead),
1159 aalg_desc->uinfo.auth.icv_fullbits / 8);
1160 goto free_key;
1161 }
1162
1163 err = crypto_aead_setauthsize(
1164 aead, x->aalg->alg_trunc_len / 8);
1165 if (err)
1166 goto free_key;
1167 }
1168
1169 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1170 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1171
1172 err = crypto_aead_setkey(aead, key, keylen);
1173
1174 free_key:
1175 kfree(key);
1176
1177 error:
1178 return err;
1179 }
1180
1181 static int esp6_init_state(struct xfrm_state *x)
1182 {
1183 struct crypto_aead *aead;
1184 u32 align;
1185 int err;
1186
1187 x->data = NULL;
1188
1189 if (x->aead)
1190 err = esp_init_aead(x);
1191 else
1192 err = esp_init_authenc(x);
1193
1194 if (err)
1195 goto error;
1196
1197 aead = x->data;
1198
1199 x->props.header_len = sizeof(struct ip_esp_hdr) +
1200 crypto_aead_ivsize(aead);
1201 switch (x->props.mode) {
1202 case XFRM_MODE_BEET:
1203 if (x->sel.family != AF_INET6)
1204 x->props.header_len += IPV4_BEET_PHMAXLEN +
1205 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
1206 break;
1207 default:
1208 case XFRM_MODE_TRANSPORT:
1209 break;
1210 case XFRM_MODE_TUNNEL:
1211 x->props.header_len += sizeof(struct ipv6hdr);
1212 break;
1213 }
1214
1215 if (x->encap) {
1216 struct xfrm_encap_tmpl *encap = x->encap;
1217
1218 switch (encap->encap_type) {
1219 default:
1220 err = -EINVAL;
1221 goto error;
1222 case UDP_ENCAP_ESPINUDP:
1223 x->props.header_len += sizeof(struct udphdr);
1224 break;
1225 case UDP_ENCAP_ESPINUDP_NON_IKE:
1226 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
1227 break;
1228 #ifdef CONFIG_INET6_ESPINTCP
1229 case TCP_ENCAP_ESPINTCP:
1230 /* only the length field, TCP encap is done by
1231 * the socket
1232 */
1233 x->props.header_len += 2;
1234 break;
1235 #endif
1236 }
1237 }
1238
1239 align = ALIGN(crypto_aead_blocksize(aead), 4);
1240 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1241
1242 error:
1243 return err;
1244 }
1245
1246 static int esp6_rcv_cb(struct sk_buff *skb, int err)
1247 {
1248 return 0;
1249 }
1250
1251 static const struct xfrm_type esp6_type = {
1252 .owner = THIS_MODULE,
1253 .proto = IPPROTO_ESP,
1254 .flags = XFRM_TYPE_REPLAY_PROT,
1255 .init_state = esp6_init_state,
1256 .destructor = esp6_destroy,
1257 .input = esp6_input,
1258 .output = esp6_output,
1259 };
1260
1261 static struct xfrm6_protocol esp6_protocol = {
1262 .handler = xfrm6_rcv,
1263 .input_handler = xfrm_input,
1264 .cb_handler = esp6_rcv_cb,
1265 .err_handler = esp6_err,
1266 .priority = 0,
1267 };
1268
1269 static int __init esp6_init(void)
1270 {
1271 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
1272 pr_info("%s: can't add xfrm type\n", __func__);
1273 return -EAGAIN;
1274 }
1275 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) {
1276 pr_info("%s: can't add protocol\n", __func__);
1277 xfrm_unregister_type(&esp6_type, AF_INET6);
1278 return -EAGAIN;
1279 }
1280
1281 return 0;
1282 }
1283
1284 static void __exit esp6_fini(void)
1285 {
1286 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0)
1287 pr_info("%s: can't remove protocol\n", __func__);
1288 xfrm_unregister_type(&esp6_type, AF_INET6);
1289 }
1290
1291 module_init(esp6_init);
1292 module_exit(esp6_fini);
1293
1294 MODULE_LICENSE("GPL");
1295 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
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