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1// SPDX-License-Identifier: GPL-2.0-only
2#define pr_fmt(fmt) "IPsec: " fmt
3
4#include <crypto/aead.h>
5#include <crypto/authenc.h>
6#include <linux/err.h>
7#include <linux/module.h>
8#include <net/ip.h>
9#include <net/xfrm.h>
10#include <net/esp.h>
11#include <linux/scatterlist.h>
12#include <linux/kernel.h>
13#include <linux/pfkeyv2.h>
14#include <linux/rtnetlink.h>
15#include <linux/slab.h>
16#include <linux/spinlock.h>
17#include <linux/in6.h>
18#include <net/icmp.h>
19#include <net/protocol.h>
20#include <net/udp.h>
21#include <net/tcp.h>
22#include <net/espintcp.h>
23#include <linux/skbuff_ref.h>
24
25#include <linux/highmem.h>
26
27struct esp_skb_cb {
28 struct xfrm_skb_cb xfrm;
29 void *tmp;
30};
31
32struct esp_output_extra {
33 __be32 seqhi;
34 u32 esphoff;
35};
36
37#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
38
39/*
40 * Allocate an AEAD request structure with extra space for SG and IV.
41 *
42 * For alignment considerations the IV is placed at the front, followed
43 * by the request and finally the SG list.
44 *
45 * TODO: Use spare space in skb for this where possible.
46 */
47static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen)
48{
49 unsigned int len;
50
51 len = extralen;
52
53 len += crypto_aead_ivsize(aead);
54
55 if (len) {
56 len += crypto_aead_alignmask(aead) &
57 ~(crypto_tfm_ctx_alignment() - 1);
58 len = ALIGN(len, crypto_tfm_ctx_alignment());
59 }
60
61 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
62 len = ALIGN(len, __alignof__(struct scatterlist));
63
64 len += sizeof(struct scatterlist) * nfrags;
65
66 return kmalloc(len, GFP_ATOMIC);
67}
68
69static inline void *esp_tmp_extra(void *tmp)
70{
71 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
72}
73
74static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen)
75{
76 return crypto_aead_ivsize(aead) ?
77 PTR_ALIGN((u8 *)tmp + extralen,
78 crypto_aead_alignmask(aead) + 1) : tmp + extralen;
79}
80
81static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
82{
83 struct aead_request *req;
84
85 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
86 crypto_tfm_ctx_alignment());
87 aead_request_set_tfm(req, aead);
88 return req;
89}
90
91static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
92 struct aead_request *req)
93{
94 return (void *)ALIGN((unsigned long)(req + 1) +
95 crypto_aead_reqsize(aead),
96 __alignof__(struct scatterlist));
97}
98
99static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb)
100{
101 struct crypto_aead *aead = x->data;
102 int extralen = 0;
103 u8 *iv;
104 struct aead_request *req;
105 struct scatterlist *sg;
106
107 if (x->props.flags & XFRM_STATE_ESN)
108 extralen += sizeof(struct esp_output_extra);
109
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 skb_page_unref(page_to_netmem(sg_page(sg)),
119 skb->pp_recycle);
120}
121
122#ifdef CONFIG_INET_ESPINTCP
123struct esp_tcp_sk {
124 struct sock *sk;
125 struct rcu_head rcu;
126};
127
128static void esp_free_tcp_sk(struct rcu_head *head)
129{
130 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu);
131
132 sock_put(esk->sk);
133 kfree(esk);
134}
135
136static struct sock *esp_find_tcp_sk(struct xfrm_state *x)
137{
138 struct xfrm_encap_tmpl *encap = x->encap;
139 struct net *net = xs_net(x);
140 struct esp_tcp_sk *esk;
141 __be16 sport, dport;
142 struct sock *nsk;
143 struct sock *sk;
144
145 sk = rcu_dereference(x->encap_sk);
146 if (sk && sk->sk_state == TCP_ESTABLISHED)
147 return sk;
148
149 spin_lock_bh(&x->lock);
150 sport = encap->encap_sport;
151 dport = encap->encap_dport;
152 nsk = rcu_dereference_protected(x->encap_sk,
153 lockdep_is_held(&x->lock));
154 if (sk && sk == nsk) {
155 esk = kmalloc(sizeof(*esk), GFP_ATOMIC);
156 if (!esk) {
157 spin_unlock_bh(&x->lock);
158 return ERR_PTR(-ENOMEM);
159 }
160 RCU_INIT_POINTER(x->encap_sk, NULL);
161 esk->sk = sk;
162 call_rcu(&esk->rcu, esp_free_tcp_sk);
163 }
164 spin_unlock_bh(&x->lock);
165
166 sk = inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, x->id.daddr.a4,
167 dport, x->props.saddr.a4, sport, 0);
168 if (!sk)
169 return ERR_PTR(-ENOENT);
170
171 if (!tcp_is_ulp_esp(sk)) {
172 sock_put(sk);
173 return ERR_PTR(-EINVAL);
174 }
175
176 spin_lock_bh(&x->lock);
177 nsk = rcu_dereference_protected(x->encap_sk,
178 lockdep_is_held(&x->lock));
179 if (encap->encap_sport != sport ||
180 encap->encap_dport != dport) {
181 sock_put(sk);
182 sk = nsk ?: ERR_PTR(-EREMCHG);
183 } else if (sk == nsk) {
184 sock_put(sk);
185 } else {
186 rcu_assign_pointer(x->encap_sk, sk);
187 }
188 spin_unlock_bh(&x->lock);
189
190 return sk;
191}
192
193static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
194{
195 struct sock *sk;
196 int err;
197
198 rcu_read_lock();
199
200 sk = esp_find_tcp_sk(x);
201 err = PTR_ERR_OR_ZERO(sk);
202 if (err)
203 goto out;
204
205 bh_lock_sock(sk);
206 if (sock_owned_by_user(sk))
207 err = espintcp_queue_out(sk, skb);
208 else
209 err = espintcp_push_skb(sk, skb);
210 bh_unlock_sock(sk);
211
212out:
213 rcu_read_unlock();
214 return err;
215}
216
217static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
218 struct sk_buff *skb)
219{
220 struct dst_entry *dst = skb_dst(skb);
221 struct xfrm_state *x = dst->xfrm;
222
223 return esp_output_tcp_finish(x, skb);
224}
225
226static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
227{
228 int err;
229
230 local_bh_disable();
231 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
232 local_bh_enable();
233
234 /* EINPROGRESS just happens to do the right thing. It
235 * actually means that the skb has been consumed and
236 * isn't coming back.
237 */
238 return err ?: -EINPROGRESS;
239}
240#else
241static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
242{
243 WARN_ON(1);
244 return -EOPNOTSUPP;
245}
246#endif
247
248static void esp_output_done(void *data, int err)
249{
250 struct sk_buff *skb = data;
251 struct xfrm_offload *xo = xfrm_offload(skb);
252 void *tmp;
253 struct xfrm_state *x;
254
255 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
256 struct sec_path *sp = skb_sec_path(skb);
257
258 x = sp->xvec[sp->len - 1];
259 } else {
260 x = skb_dst(skb)->xfrm;
261 }
262
263 tmp = ESP_SKB_CB(skb)->tmp;
264 esp_ssg_unref(x, tmp, skb);
265 kfree(tmp);
266
267 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
268 if (err) {
269 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
270 kfree_skb(skb);
271 return;
272 }
273
274 skb_push(skb, skb->data - skb_mac_header(skb));
275 secpath_reset(skb);
276 xfrm_dev_resume(skb);
277 } else {
278 if (!err &&
279 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
280 esp_output_tail_tcp(x, skb);
281 else
282 xfrm_output_resume(skb->sk, skb, err);
283 }
284}
285
286/* Move ESP header back into place. */
287static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
288{
289 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
290 void *tmp = ESP_SKB_CB(skb)->tmp;
291 __be32 *seqhi = esp_tmp_extra(tmp);
292
293 esph->seq_no = esph->spi;
294 esph->spi = *seqhi;
295}
296
297static void esp_output_restore_header(struct sk_buff *skb)
298{
299 void *tmp = ESP_SKB_CB(skb)->tmp;
300 struct esp_output_extra *extra = esp_tmp_extra(tmp);
301
302 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
303 sizeof(__be32));
304}
305
306static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
307 struct xfrm_state *x,
308 struct ip_esp_hdr *esph,
309 struct esp_output_extra *extra)
310{
311 /* For ESN we move the header forward by 4 bytes to
312 * accommodate the high bits. We will move it back after
313 * encryption.
314 */
315 if ((x->props.flags & XFRM_STATE_ESN)) {
316 __u32 seqhi;
317 struct xfrm_offload *xo = xfrm_offload(skb);
318
319 if (xo)
320 seqhi = xo->seq.hi;
321 else
322 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
323
324 extra->esphoff = (unsigned char *)esph -
325 skb_transport_header(skb);
326 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
327 extra->seqhi = esph->spi;
328 esph->seq_no = htonl(seqhi);
329 }
330
331 esph->spi = x->id.spi;
332
333 return esph;
334}
335
336static void esp_output_done_esn(void *data, int err)
337{
338 struct sk_buff *skb = data;
339
340 esp_output_restore_header(skb);
341 esp_output_done(data, err);
342}
343
344static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb,
345 int encap_type,
346 struct esp_info *esp,
347 __be16 sport,
348 __be16 dport)
349{
350 struct udphdr *uh;
351 unsigned int len;
352 struct xfrm_offload *xo = xfrm_offload(skb);
353
354 len = skb->len + esp->tailen - skb_transport_offset(skb);
355 if (len + sizeof(struct iphdr) > IP_MAX_MTU)
356 return ERR_PTR(-EMSGSIZE);
357
358 uh = (struct udphdr *)esp->esph;
359 uh->source = sport;
360 uh->dest = dport;
361 uh->len = htons(len);
362 uh->check = 0;
363
364 /* For IPv4 ESP with UDP encapsulation, if xo is not null, the skb is in the crypto offload
365 * data path, which means that esp_output_udp_encap is called outside of the XFRM stack.
366 * In this case, the mac header doesn't point to the IPv4 protocol field, so don't set it.
367 */
368 if (!xo || encap_type != UDP_ENCAP_ESPINUDP)
369 *skb_mac_header(skb) = IPPROTO_UDP;
370
371 return (struct ip_esp_hdr *)(uh + 1);
372}
373
374#ifdef CONFIG_INET_ESPINTCP
375static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
376 struct sk_buff *skb,
377 struct esp_info *esp)
378{
379 __be16 *lenp = (void *)esp->esph;
380 struct ip_esp_hdr *esph;
381 unsigned int len;
382 struct sock *sk;
383
384 len = skb->len + esp->tailen - skb_transport_offset(skb);
385 if (len > IP_MAX_MTU)
386 return ERR_PTR(-EMSGSIZE);
387
388 rcu_read_lock();
389 sk = esp_find_tcp_sk(x);
390 rcu_read_unlock();
391
392 if (IS_ERR(sk))
393 return ERR_CAST(sk);
394
395 *lenp = htons(len);
396 esph = (struct ip_esp_hdr *)(lenp + 1);
397
398 return esph;
399}
400#else
401static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
402 struct sk_buff *skb,
403 struct esp_info *esp)
404{
405 return ERR_PTR(-EOPNOTSUPP);
406}
407#endif
408
409static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb,
410 struct esp_info *esp)
411{
412 struct xfrm_encap_tmpl *encap = x->encap;
413 struct ip_esp_hdr *esph;
414 __be16 sport, dport;
415 int encap_type;
416
417 spin_lock_bh(&x->lock);
418 sport = encap->encap_sport;
419 dport = encap->encap_dport;
420 encap_type = encap->encap_type;
421 spin_unlock_bh(&x->lock);
422
423 switch (encap_type) {
424 default:
425 case UDP_ENCAP_ESPINUDP:
426 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport);
427 break;
428 case TCP_ENCAP_ESPINTCP:
429 esph = esp_output_tcp_encap(x, skb, esp);
430 break;
431 }
432
433 if (IS_ERR(esph))
434 return PTR_ERR(esph);
435
436 esp->esph = esph;
437
438 return 0;
439}
440
441int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
442{
443 u8 *tail;
444 int nfrags;
445 int esph_offset;
446 struct page *page;
447 struct sk_buff *trailer;
448 int tailen = esp->tailen;
449
450 /* this is non-NULL only with TCP/UDP Encapsulation */
451 if (x->encap) {
452 int err = esp_output_encap(x, skb, esp);
453
454 if (err < 0)
455 return err;
456 }
457
458 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
459 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
460 goto cow;
461
462 if (!skb_cloned(skb)) {
463 if (tailen <= skb_tailroom(skb)) {
464 nfrags = 1;
465 trailer = skb;
466 tail = skb_tail_pointer(trailer);
467
468 goto skip_cow;
469 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
470 && !skb_has_frag_list(skb)) {
471 int allocsize;
472 struct sock *sk = skb->sk;
473 struct page_frag *pfrag = &x->xfrag;
474
475 esp->inplace = false;
476
477 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
478
479 spin_lock_bh(&x->lock);
480
481 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
482 spin_unlock_bh(&x->lock);
483 goto cow;
484 }
485
486 page = pfrag->page;
487 get_page(page);
488
489 tail = page_address(page) + pfrag->offset;
490
491 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
492
493 nfrags = skb_shinfo(skb)->nr_frags;
494
495 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
496 tailen);
497 skb_shinfo(skb)->nr_frags = ++nfrags;
498
499 pfrag->offset = pfrag->offset + allocsize;
500
501 spin_unlock_bh(&x->lock);
502
503 nfrags++;
504
505 skb_len_add(skb, tailen);
506 if (sk && sk_fullsock(sk))
507 refcount_add(tailen, &sk->sk_wmem_alloc);
508
509 goto out;
510 }
511 }
512
513cow:
514 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
515
516 nfrags = skb_cow_data(skb, tailen, &trailer);
517 if (nfrags < 0)
518 goto out;
519 tail = skb_tail_pointer(trailer);
520 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
521
522skip_cow:
523 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
524 pskb_put(skb, trailer, tailen);
525
526out:
527 return nfrags;
528}
529EXPORT_SYMBOL_GPL(esp_output_head);
530
531int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
532{
533 u8 *iv;
534 int alen;
535 void *tmp;
536 int ivlen;
537 int assoclen;
538 int extralen;
539 struct page *page;
540 struct ip_esp_hdr *esph;
541 struct crypto_aead *aead;
542 struct aead_request *req;
543 struct scatterlist *sg, *dsg;
544 struct esp_output_extra *extra;
545 int err = -ENOMEM;
546
547 assoclen = sizeof(struct ip_esp_hdr);
548 extralen = 0;
549
550 if (x->props.flags & XFRM_STATE_ESN) {
551 extralen += sizeof(*extra);
552 assoclen += sizeof(__be32);
553 }
554
555 aead = x->data;
556 alen = crypto_aead_authsize(aead);
557 ivlen = crypto_aead_ivsize(aead);
558
559 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
560 if (!tmp)
561 goto error;
562
563 extra = esp_tmp_extra(tmp);
564 iv = esp_tmp_iv(aead, tmp, extralen);
565 req = esp_tmp_req(aead, iv);
566 sg = esp_req_sg(aead, req);
567
568 if (esp->inplace)
569 dsg = sg;
570 else
571 dsg = &sg[esp->nfrags];
572
573 esph = esp_output_set_extra(skb, x, esp->esph, extra);
574 esp->esph = esph;
575
576 sg_init_table(sg, esp->nfrags);
577 err = skb_to_sgvec(skb, sg,
578 (unsigned char *)esph - skb->data,
579 assoclen + ivlen + esp->clen + alen);
580 if (unlikely(err < 0))
581 goto error_free;
582
583 if (!esp->inplace) {
584 int allocsize;
585 struct page_frag *pfrag = &x->xfrag;
586
587 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
588
589 spin_lock_bh(&x->lock);
590 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
591 spin_unlock_bh(&x->lock);
592 goto error_free;
593 }
594
595 skb_shinfo(skb)->nr_frags = 1;
596
597 page = pfrag->page;
598 get_page(page);
599 /* replace page frags in skb with new page */
600 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
601 pfrag->offset = pfrag->offset + allocsize;
602 spin_unlock_bh(&x->lock);
603
604 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
605 err = skb_to_sgvec(skb, dsg,
606 (unsigned char *)esph - skb->data,
607 assoclen + ivlen + esp->clen + alen);
608 if (unlikely(err < 0))
609 goto error_free;
610 }
611
612 if ((x->props.flags & XFRM_STATE_ESN))
613 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
614 else
615 aead_request_set_callback(req, 0, esp_output_done, skb);
616
617 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
618 aead_request_set_ad(req, assoclen);
619
620 memset(iv, 0, ivlen);
621 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
622 min(ivlen, 8));
623
624 ESP_SKB_CB(skb)->tmp = tmp;
625 err = crypto_aead_encrypt(req);
626
627 switch (err) {
628 case -EINPROGRESS:
629 goto error;
630
631 case -ENOSPC:
632 err = NET_XMIT_DROP;
633 break;
634
635 case 0:
636 if ((x->props.flags & XFRM_STATE_ESN))
637 esp_output_restore_header(skb);
638 }
639
640 if (sg != dsg)
641 esp_ssg_unref(x, tmp, skb);
642
643 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
644 err = esp_output_tail_tcp(x, skb);
645
646error_free:
647 kfree(tmp);
648error:
649 return err;
650}
651EXPORT_SYMBOL_GPL(esp_output_tail);
652
653static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
654{
655 int alen;
656 int blksize;
657 struct ip_esp_hdr *esph;
658 struct crypto_aead *aead;
659 struct esp_info esp;
660
661 esp.inplace = true;
662
663 esp.proto = *skb_mac_header(skb);
664 *skb_mac_header(skb) = IPPROTO_ESP;
665
666 /* skb is pure payload to encrypt */
667
668 aead = x->data;
669 alen = crypto_aead_authsize(aead);
670
671 esp.tfclen = 0;
672 if (x->tfcpad) {
673 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
674 u32 padto;
675
676 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
677 if (skb->len < padto)
678 esp.tfclen = padto - skb->len;
679 }
680 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
681 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
682 esp.plen = esp.clen - skb->len - esp.tfclen;
683 esp.tailen = esp.tfclen + esp.plen + alen;
684
685 esp.esph = ip_esp_hdr(skb);
686
687 esp.nfrags = esp_output_head(x, skb, &esp);
688 if (esp.nfrags < 0)
689 return esp.nfrags;
690
691 esph = esp.esph;
692 esph->spi = x->id.spi;
693
694 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
695 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
696 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
697
698 skb_push(skb, -skb_network_offset(skb));
699
700 return esp_output_tail(x, skb, &esp);
701}
702
703static inline int esp_remove_trailer(struct sk_buff *skb)
704{
705 struct xfrm_state *x = xfrm_input_state(skb);
706 struct crypto_aead *aead = x->data;
707 int alen, hlen, elen;
708 int padlen, trimlen;
709 __wsum csumdiff;
710 u8 nexthdr[2];
711 int ret;
712
713 alen = crypto_aead_authsize(aead);
714 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
715 elen = skb->len - hlen;
716
717 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
718 BUG();
719
720 ret = -EINVAL;
721 padlen = nexthdr[0];
722 if (padlen + 2 + alen >= elen) {
723 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
724 padlen + 2, elen - alen);
725 goto out;
726 }
727
728 trimlen = alen + padlen + 2;
729 if (skb->ip_summed == CHECKSUM_COMPLETE) {
730 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
731 skb->csum = csum_block_sub(skb->csum, csumdiff,
732 skb->len - trimlen);
733 }
734 ret = pskb_trim(skb, skb->len - trimlen);
735 if (unlikely(ret))
736 return ret;
737
738 ret = nexthdr[1];
739
740out:
741 return ret;
742}
743
744int esp_input_done2(struct sk_buff *skb, int err)
745{
746 const struct iphdr *iph;
747 struct xfrm_state *x = xfrm_input_state(skb);
748 struct xfrm_offload *xo = xfrm_offload(skb);
749 struct crypto_aead *aead = x->data;
750 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
751 int ihl;
752
753 if (!xo || !(xo->flags & CRYPTO_DONE))
754 kfree(ESP_SKB_CB(skb)->tmp);
755
756 if (unlikely(err))
757 goto out;
758
759 err = esp_remove_trailer(skb);
760 if (unlikely(err < 0))
761 goto out;
762
763 iph = ip_hdr(skb);
764 ihl = iph->ihl * 4;
765
766 if (x->encap) {
767 struct xfrm_encap_tmpl *encap = x->encap;
768 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl);
769 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
770 __be16 source;
771
772 switch (x->encap->encap_type) {
773 case TCP_ENCAP_ESPINTCP:
774 source = th->source;
775 break;
776 case UDP_ENCAP_ESPINUDP:
777 source = uh->source;
778 break;
779 default:
780 WARN_ON_ONCE(1);
781 err = -EINVAL;
782 goto out;
783 }
784
785 /*
786 * 1) if the NAT-T peer's IP or port changed then
787 * advertise the change to the keying daemon.
788 * This is an inbound SA, so just compare
789 * SRC ports.
790 */
791 if (iph->saddr != x->props.saddr.a4 ||
792 source != encap->encap_sport) {
793 xfrm_address_t ipaddr;
794
795 ipaddr.a4 = iph->saddr;
796 km_new_mapping(x, &ipaddr, source);
797
798 /* XXX: perhaps add an extra
799 * policy check here, to see
800 * if we should allow or
801 * reject a packet from a
802 * different source
803 * address/port.
804 */
805 }
806
807 /*
808 * 2) ignore UDP/TCP checksums in case
809 * of NAT-T in Transport Mode, or
810 * perform other post-processing fixes
811 * as per draft-ietf-ipsec-udp-encaps-06,
812 * section 3.1.2
813 */
814 if (x->props.mode == XFRM_MODE_TRANSPORT)
815 skb->ip_summed = CHECKSUM_UNNECESSARY;
816 }
817
818 skb_pull_rcsum(skb, hlen);
819 if (x->props.mode == XFRM_MODE_TUNNEL)
820 skb_reset_transport_header(skb);
821 else
822 skb_set_transport_header(skb, -ihl);
823
824 /* RFC4303: Drop dummy packets without any error */
825 if (err == IPPROTO_NONE)
826 err = -EINVAL;
827
828out:
829 return err;
830}
831EXPORT_SYMBOL_GPL(esp_input_done2);
832
833static void esp_input_done(void *data, int err)
834{
835 struct sk_buff *skb = data;
836
837 xfrm_input_resume(skb, esp_input_done2(skb, err));
838}
839
840static void esp_input_restore_header(struct sk_buff *skb)
841{
842 esp_restore_header(skb, 0);
843 __skb_pull(skb, 4);
844}
845
846static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
847{
848 struct xfrm_state *x = xfrm_input_state(skb);
849 struct ip_esp_hdr *esph;
850
851 /* For ESN we move the header forward by 4 bytes to
852 * accommodate the high bits. We will move it back after
853 * decryption.
854 */
855 if ((x->props.flags & XFRM_STATE_ESN)) {
856 esph = skb_push(skb, 4);
857 *seqhi = esph->spi;
858 esph->spi = esph->seq_no;
859 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
860 }
861}
862
863static void esp_input_done_esn(void *data, int err)
864{
865 struct sk_buff *skb = data;
866
867 esp_input_restore_header(skb);
868 esp_input_done(data, err);
869}
870
871/*
872 * Note: detecting truncated vs. non-truncated authentication data is very
873 * expensive, so we only support truncated data, which is the recommended
874 * and common case.
875 */
876static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
877{
878 struct crypto_aead *aead = x->data;
879 struct aead_request *req;
880 struct sk_buff *trailer;
881 int ivlen = crypto_aead_ivsize(aead);
882 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
883 int nfrags;
884 int assoclen;
885 int seqhilen;
886 __be32 *seqhi;
887 void *tmp;
888 u8 *iv;
889 struct scatterlist *sg;
890 int err = -EINVAL;
891
892 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
893 goto out;
894
895 if (elen <= 0)
896 goto out;
897
898 assoclen = sizeof(struct ip_esp_hdr);
899 seqhilen = 0;
900
901 if (x->props.flags & XFRM_STATE_ESN) {
902 seqhilen += sizeof(__be32);
903 assoclen += seqhilen;
904 }
905
906 if (!skb_cloned(skb)) {
907 if (!skb_is_nonlinear(skb)) {
908 nfrags = 1;
909
910 goto skip_cow;
911 } else if (!skb_has_frag_list(skb)) {
912 nfrags = skb_shinfo(skb)->nr_frags;
913 nfrags++;
914
915 goto skip_cow;
916 }
917 }
918
919 err = skb_cow_data(skb, 0, &trailer);
920 if (err < 0)
921 goto out;
922
923 nfrags = err;
924
925skip_cow:
926 err = -ENOMEM;
927 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
928 if (!tmp)
929 goto out;
930
931 ESP_SKB_CB(skb)->tmp = tmp;
932 seqhi = esp_tmp_extra(tmp);
933 iv = esp_tmp_iv(aead, tmp, seqhilen);
934 req = esp_tmp_req(aead, iv);
935 sg = esp_req_sg(aead, req);
936
937 esp_input_set_header(skb, seqhi);
938
939 sg_init_table(sg, nfrags);
940 err = skb_to_sgvec(skb, sg, 0, skb->len);
941 if (unlikely(err < 0)) {
942 kfree(tmp);
943 goto out;
944 }
945
946 skb->ip_summed = CHECKSUM_NONE;
947
948 if ((x->props.flags & XFRM_STATE_ESN))
949 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
950 else
951 aead_request_set_callback(req, 0, esp_input_done, skb);
952
953 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
954 aead_request_set_ad(req, assoclen);
955
956 err = crypto_aead_decrypt(req);
957 if (err == -EINPROGRESS)
958 goto out;
959
960 if ((x->props.flags & XFRM_STATE_ESN))
961 esp_input_restore_header(skb);
962
963 err = esp_input_done2(skb, err);
964
965out:
966 return err;
967}
968
969static int esp4_err(struct sk_buff *skb, u32 info)
970{
971 struct net *net = dev_net(skb->dev);
972 const struct iphdr *iph = (const struct iphdr *)skb->data;
973 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
974 struct xfrm_state *x;
975
976 switch (icmp_hdr(skb)->type) {
977 case ICMP_DEST_UNREACH:
978 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
979 return 0;
980 break;
981 case ICMP_REDIRECT:
982 break;
983 default:
984 return 0;
985 }
986
987 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
988 esph->spi, IPPROTO_ESP, AF_INET);
989 if (!x)
990 return 0;
991
992 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
993 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP);
994 else
995 ipv4_redirect(skb, net, 0, IPPROTO_ESP);
996 xfrm_state_put(x);
997
998 return 0;
999}
1000
1001static void esp_destroy(struct xfrm_state *x)
1002{
1003 struct crypto_aead *aead = x->data;
1004
1005 if (!aead)
1006 return;
1007
1008 crypto_free_aead(aead);
1009}
1010
1011static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
1012{
1013 char aead_name[CRYPTO_MAX_ALG_NAME];
1014 struct crypto_aead *aead;
1015 int err;
1016
1017 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1018 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
1019 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1020 return -ENAMETOOLONG;
1021 }
1022
1023 aead = crypto_alloc_aead(aead_name, 0, 0);
1024 err = PTR_ERR(aead);
1025 if (IS_ERR(aead))
1026 goto error;
1027
1028 x->data = aead;
1029
1030 err = crypto_aead_setkey(aead, x->aead->alg_key,
1031 (x->aead->alg_key_len + 7) / 8);
1032 if (err)
1033 goto error;
1034
1035 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1036 if (err)
1037 goto error;
1038
1039 return 0;
1040
1041error:
1042 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1043 return err;
1044}
1045
1046static int esp_init_authenc(struct xfrm_state *x,
1047 struct netlink_ext_ack *extack)
1048{
1049 struct crypto_aead *aead;
1050 struct crypto_authenc_key_param *param;
1051 struct rtattr *rta;
1052 char *key;
1053 char *p;
1054 char authenc_name[CRYPTO_MAX_ALG_NAME];
1055 unsigned int keylen;
1056 int err;
1057
1058 err = -ENAMETOOLONG;
1059
1060 if ((x->props.flags & XFRM_STATE_ESN)) {
1061 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1062 "%s%sauthencesn(%s,%s)%s",
1063 x->geniv ?: "", x->geniv ? "(" : "",
1064 x->aalg ? x->aalg->alg_name : "digest_null",
1065 x->ealg->alg_name,
1066 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1067 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1068 goto error;
1069 }
1070 } else {
1071 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1072 "%s%sauthenc(%s,%s)%s",
1073 x->geniv ?: "", x->geniv ? "(" : "",
1074 x->aalg ? x->aalg->alg_name : "digest_null",
1075 x->ealg->alg_name,
1076 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1077 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1078 goto error;
1079 }
1080 }
1081
1082 aead = crypto_alloc_aead(authenc_name, 0, 0);
1083 err = PTR_ERR(aead);
1084 if (IS_ERR(aead)) {
1085 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1086 goto error;
1087 }
1088
1089 x->data = aead;
1090
1091 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1092 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1093 err = -ENOMEM;
1094 key = kmalloc(keylen, GFP_KERNEL);
1095 if (!key)
1096 goto error;
1097
1098 p = key;
1099 rta = (void *)p;
1100 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1101 rta->rta_len = RTA_LENGTH(sizeof(*param));
1102 param = RTA_DATA(rta);
1103 p += RTA_SPACE(sizeof(*param));
1104
1105 if (x->aalg) {
1106 struct xfrm_algo_desc *aalg_desc;
1107
1108 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1109 p += (x->aalg->alg_key_len + 7) / 8;
1110
1111 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1112 BUG_ON(!aalg_desc);
1113
1114 err = -EINVAL;
1115 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1116 crypto_aead_authsize(aead)) {
1117 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1118 goto free_key;
1119 }
1120
1121 err = crypto_aead_setauthsize(
1122 aead, x->aalg->alg_trunc_len / 8);
1123 if (err) {
1124 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1125 goto free_key;
1126 }
1127 }
1128
1129 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1130 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1131
1132 err = crypto_aead_setkey(aead, key, keylen);
1133
1134free_key:
1135 kfree_sensitive(key);
1136
1137error:
1138 return err;
1139}
1140
1141static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
1142{
1143 struct crypto_aead *aead;
1144 u32 align;
1145 int err;
1146
1147 x->data = NULL;
1148
1149 if (x->aead) {
1150 err = esp_init_aead(x, extack);
1151 } else if (x->ealg) {
1152 err = esp_init_authenc(x, extack);
1153 } else {
1154 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided");
1155 err = -EINVAL;
1156 }
1157
1158 if (err)
1159 goto error;
1160
1161 aead = x->data;
1162
1163 x->props.header_len = sizeof(struct ip_esp_hdr) +
1164 crypto_aead_ivsize(aead);
1165 if (x->props.mode == XFRM_MODE_TUNNEL)
1166 x->props.header_len += sizeof(struct iphdr);
1167 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
1168 x->props.header_len += IPV4_BEET_PHMAXLEN;
1169 if (x->encap) {
1170 struct xfrm_encap_tmpl *encap = x->encap;
1171
1172 switch (encap->encap_type) {
1173 default:
1174 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP");
1175 err = -EINVAL;
1176 goto error;
1177 case UDP_ENCAP_ESPINUDP:
1178 x->props.header_len += sizeof(struct udphdr);
1179 break;
1180#ifdef CONFIG_INET_ESPINTCP
1181 case TCP_ENCAP_ESPINTCP:
1182 /* only the length field, TCP encap is done by
1183 * the socket
1184 */
1185 x->props.header_len += 2;
1186 break;
1187#endif
1188 }
1189 }
1190
1191 align = ALIGN(crypto_aead_blocksize(aead), 4);
1192 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1193
1194error:
1195 return err;
1196}
1197
1198static int esp4_rcv_cb(struct sk_buff *skb, int err)
1199{
1200 return 0;
1201}
1202
1203static const struct xfrm_type esp_type =
1204{
1205 .owner = THIS_MODULE,
1206 .proto = IPPROTO_ESP,
1207 .flags = XFRM_TYPE_REPLAY_PROT,
1208 .init_state = esp_init_state,
1209 .destructor = esp_destroy,
1210 .input = esp_input,
1211 .output = esp_output,
1212};
1213
1214static struct xfrm4_protocol esp4_protocol = {
1215 .handler = xfrm4_rcv,
1216 .input_handler = xfrm_input,
1217 .cb_handler = esp4_rcv_cb,
1218 .err_handler = esp4_err,
1219 .priority = 0,
1220};
1221
1222static int __init esp4_init(void)
1223{
1224 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1225 pr_info("%s: can't add xfrm type\n", __func__);
1226 return -EAGAIN;
1227 }
1228 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1229 pr_info("%s: can't add protocol\n", __func__);
1230 xfrm_unregister_type(&esp_type, AF_INET);
1231 return -EAGAIN;
1232 }
1233 return 0;
1234}
1235
1236static void __exit esp4_fini(void)
1237{
1238 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1239 pr_info("%s: can't remove protocol\n", __func__);
1240 xfrm_unregister_type(&esp_type, AF_INET);
1241}
1242
1243module_init(esp4_init);
1244module_exit(esp4_fini);
1245MODULE_DESCRIPTION("IPv4 ESP transformation library");
1246MODULE_LICENSE("GPL");
1247MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
1#include <crypto/aead.h>
2#include <crypto/authenc.h>
3#include <linux/err.h>
4#include <linux/module.h>
5#include <net/ip.h>
6#include <net/xfrm.h>
7#include <net/esp.h>
8#include <linux/scatterlist.h>
9#include <linux/kernel.h>
10#include <linux/pfkeyv2.h>
11#include <linux/rtnetlink.h>
12#include <linux/slab.h>
13#include <linux/spinlock.h>
14#include <linux/in6.h>
15#include <net/icmp.h>
16#include <net/protocol.h>
17#include <net/udp.h>
18
19struct esp_skb_cb {
20 struct xfrm_skb_cb xfrm;
21 void *tmp;
22};
23
24#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
25
26static u32 esp4_get_mtu(struct xfrm_state *x, int mtu);
27
28/*
29 * Allocate an AEAD request structure with extra space for SG and IV.
30 *
31 * For alignment considerations the IV is placed at the front, followed
32 * by the request and finally the SG list.
33 *
34 * TODO: Use spare space in skb for this where possible.
35 */
36static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqhilen)
37{
38 unsigned int len;
39
40 len = seqhilen;
41
42 len += crypto_aead_ivsize(aead);
43
44 if (len) {
45 len += crypto_aead_alignmask(aead) &
46 ~(crypto_tfm_ctx_alignment() - 1);
47 len = ALIGN(len, crypto_tfm_ctx_alignment());
48 }
49
50 len += sizeof(struct aead_givcrypt_request) + crypto_aead_reqsize(aead);
51 len = ALIGN(len, __alignof__(struct scatterlist));
52
53 len += sizeof(struct scatterlist) * nfrags;
54
55 return kmalloc(len, GFP_ATOMIC);
56}
57
58static inline __be32 *esp_tmp_seqhi(void *tmp)
59{
60 return PTR_ALIGN((__be32 *)tmp, __alignof__(__be32));
61}
62static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
63{
64 return crypto_aead_ivsize(aead) ?
65 PTR_ALIGN((u8 *)tmp + seqhilen,
66 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
67}
68
69static inline struct aead_givcrypt_request *esp_tmp_givreq(
70 struct crypto_aead *aead, u8 *iv)
71{
72 struct aead_givcrypt_request *req;
73
74 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
75 crypto_tfm_ctx_alignment());
76 aead_givcrypt_set_tfm(req, aead);
77 return req;
78}
79
80static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
81{
82 struct aead_request *req;
83
84 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
85 crypto_tfm_ctx_alignment());
86 aead_request_set_tfm(req, aead);
87 return req;
88}
89
90static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
91 struct aead_request *req)
92{
93 return (void *)ALIGN((unsigned long)(req + 1) +
94 crypto_aead_reqsize(aead),
95 __alignof__(struct scatterlist));
96}
97
98static inline struct scatterlist *esp_givreq_sg(
99 struct crypto_aead *aead, struct aead_givcrypt_request *req)
100{
101 return (void *)ALIGN((unsigned long)(req + 1) +
102 crypto_aead_reqsize(aead),
103 __alignof__(struct scatterlist));
104}
105
106static void esp_output_done(struct crypto_async_request *base, int err)
107{
108 struct sk_buff *skb = base->data;
109
110 kfree(ESP_SKB_CB(skb)->tmp);
111 xfrm_output_resume(skb, err);
112}
113
114static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
115{
116 int err;
117 struct ip_esp_hdr *esph;
118 struct crypto_aead *aead;
119 struct aead_givcrypt_request *req;
120 struct scatterlist *sg;
121 struct scatterlist *asg;
122 struct esp_data *esp;
123 struct sk_buff *trailer;
124 void *tmp;
125 u8 *iv;
126 u8 *tail;
127 int blksize;
128 int clen;
129 int alen;
130 int plen;
131 int tfclen;
132 int nfrags;
133 int assoclen;
134 int sglists;
135 int seqhilen;
136 __be32 *seqhi;
137
138 /* skb is pure payload to encrypt */
139
140 err = -ENOMEM;
141
142 esp = x->data;
143 aead = esp->aead;
144 alen = crypto_aead_authsize(aead);
145
146 tfclen = 0;
147 if (x->tfcpad) {
148 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
149 u32 padto;
150
151 padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached));
152 if (skb->len < padto)
153 tfclen = padto - skb->len;
154 }
155 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
156 clen = ALIGN(skb->len + 2 + tfclen, blksize);
157 if (esp->padlen)
158 clen = ALIGN(clen, esp->padlen);
159 plen = clen - skb->len - tfclen;
160
161 err = skb_cow_data(skb, tfclen + plen + alen, &trailer);
162 if (err < 0)
163 goto error;
164 nfrags = err;
165
166 assoclen = sizeof(*esph);
167 sglists = 1;
168 seqhilen = 0;
169
170 if (x->props.flags & XFRM_STATE_ESN) {
171 sglists += 2;
172 seqhilen += sizeof(__be32);
173 assoclen += seqhilen;
174 }
175
176 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
177 if (!tmp)
178 goto error;
179
180 seqhi = esp_tmp_seqhi(tmp);
181 iv = esp_tmp_iv(aead, tmp, seqhilen);
182 req = esp_tmp_givreq(aead, iv);
183 asg = esp_givreq_sg(aead, req);
184 sg = asg + sglists;
185
186 /* Fill padding... */
187 tail = skb_tail_pointer(trailer);
188 if (tfclen) {
189 memset(tail, 0, tfclen);
190 tail += tfclen;
191 }
192 do {
193 int i;
194 for (i = 0; i < plen - 2; i++)
195 tail[i] = i + 1;
196 } while (0);
197 tail[plen - 2] = plen - 2;
198 tail[plen - 1] = *skb_mac_header(skb);
199 pskb_put(skb, trailer, clen - skb->len + alen);
200
201 skb_push(skb, -skb_network_offset(skb));
202 esph = ip_esp_hdr(skb);
203 *skb_mac_header(skb) = IPPROTO_ESP;
204
205 /* this is non-NULL only with UDP Encapsulation */
206 if (x->encap) {
207 struct xfrm_encap_tmpl *encap = x->encap;
208 struct udphdr *uh;
209 __be32 *udpdata32;
210 __be16 sport, dport;
211 int encap_type;
212
213 spin_lock_bh(&x->lock);
214 sport = encap->encap_sport;
215 dport = encap->encap_dport;
216 encap_type = encap->encap_type;
217 spin_unlock_bh(&x->lock);
218
219 uh = (struct udphdr *)esph;
220 uh->source = sport;
221 uh->dest = dport;
222 uh->len = htons(skb->len - skb_transport_offset(skb));
223 uh->check = 0;
224
225 switch (encap_type) {
226 default:
227 case UDP_ENCAP_ESPINUDP:
228 esph = (struct ip_esp_hdr *)(uh + 1);
229 break;
230 case UDP_ENCAP_ESPINUDP_NON_IKE:
231 udpdata32 = (__be32 *)(uh + 1);
232 udpdata32[0] = udpdata32[1] = 0;
233 esph = (struct ip_esp_hdr *)(udpdata32 + 2);
234 break;
235 }
236
237 *skb_mac_header(skb) = IPPROTO_UDP;
238 }
239
240 esph->spi = x->id.spi;
241 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
242
243 sg_init_table(sg, nfrags);
244 skb_to_sgvec(skb, sg,
245 esph->enc_data + crypto_aead_ivsize(aead) - skb->data,
246 clen + alen);
247
248 if ((x->props.flags & XFRM_STATE_ESN)) {
249 sg_init_table(asg, 3);
250 sg_set_buf(asg, &esph->spi, sizeof(__be32));
251 *seqhi = htonl(XFRM_SKB_CB(skb)->seq.output.hi);
252 sg_set_buf(asg + 1, seqhi, seqhilen);
253 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
254 } else
255 sg_init_one(asg, esph, sizeof(*esph));
256
257 aead_givcrypt_set_callback(req, 0, esp_output_done, skb);
258 aead_givcrypt_set_crypt(req, sg, sg, clen, iv);
259 aead_givcrypt_set_assoc(req, asg, assoclen);
260 aead_givcrypt_set_giv(req, esph->enc_data,
261 XFRM_SKB_CB(skb)->seq.output.low);
262
263 ESP_SKB_CB(skb)->tmp = tmp;
264 err = crypto_aead_givencrypt(req);
265 if (err == -EINPROGRESS)
266 goto error;
267
268 if (err == -EBUSY)
269 err = NET_XMIT_DROP;
270
271 kfree(tmp);
272
273error:
274 return err;
275}
276
277static int esp_input_done2(struct sk_buff *skb, int err)
278{
279 const struct iphdr *iph;
280 struct xfrm_state *x = xfrm_input_state(skb);
281 struct esp_data *esp = x->data;
282 struct crypto_aead *aead = esp->aead;
283 int alen = crypto_aead_authsize(aead);
284 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
285 int elen = skb->len - hlen;
286 int ihl;
287 u8 nexthdr[2];
288 int padlen;
289
290 kfree(ESP_SKB_CB(skb)->tmp);
291
292 if (unlikely(err))
293 goto out;
294
295 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
296 BUG();
297
298 err = -EINVAL;
299 padlen = nexthdr[0];
300 if (padlen + 2 + alen >= elen)
301 goto out;
302
303 /* ... check padding bits here. Silly. :-) */
304
305 iph = ip_hdr(skb);
306 ihl = iph->ihl * 4;
307
308 if (x->encap) {
309 struct xfrm_encap_tmpl *encap = x->encap;
310 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
311
312 /*
313 * 1) if the NAT-T peer's IP or port changed then
314 * advertize the change to the keying daemon.
315 * This is an inbound SA, so just compare
316 * SRC ports.
317 */
318 if (iph->saddr != x->props.saddr.a4 ||
319 uh->source != encap->encap_sport) {
320 xfrm_address_t ipaddr;
321
322 ipaddr.a4 = iph->saddr;
323 km_new_mapping(x, &ipaddr, uh->source);
324
325 /* XXX: perhaps add an extra
326 * policy check here, to see
327 * if we should allow or
328 * reject a packet from a
329 * different source
330 * address/port.
331 */
332 }
333
334 /*
335 * 2) ignore UDP/TCP checksums in case
336 * of NAT-T in Transport Mode, or
337 * perform other post-processing fixes
338 * as per draft-ietf-ipsec-udp-encaps-06,
339 * section 3.1.2
340 */
341 if (x->props.mode == XFRM_MODE_TRANSPORT)
342 skb->ip_summed = CHECKSUM_UNNECESSARY;
343 }
344
345 pskb_trim(skb, skb->len - alen - padlen - 2);
346 __skb_pull(skb, hlen);
347 skb_set_transport_header(skb, -ihl);
348
349 err = nexthdr[1];
350
351 /* RFC4303: Drop dummy packets without any error */
352 if (err == IPPROTO_NONE)
353 err = -EINVAL;
354
355out:
356 return err;
357}
358
359static void esp_input_done(struct crypto_async_request *base, int err)
360{
361 struct sk_buff *skb = base->data;
362
363 xfrm_input_resume(skb, esp_input_done2(skb, err));
364}
365
366/*
367 * Note: detecting truncated vs. non-truncated authentication data is very
368 * expensive, so we only support truncated data, which is the recommended
369 * and common case.
370 */
371static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
372{
373 struct ip_esp_hdr *esph;
374 struct esp_data *esp = x->data;
375 struct crypto_aead *aead = esp->aead;
376 struct aead_request *req;
377 struct sk_buff *trailer;
378 int elen = skb->len - sizeof(*esph) - crypto_aead_ivsize(aead);
379 int nfrags;
380 int assoclen;
381 int sglists;
382 int seqhilen;
383 __be32 *seqhi;
384 void *tmp;
385 u8 *iv;
386 struct scatterlist *sg;
387 struct scatterlist *asg;
388 int err = -EINVAL;
389
390 if (!pskb_may_pull(skb, sizeof(*esph) + crypto_aead_ivsize(aead)))
391 goto out;
392
393 if (elen <= 0)
394 goto out;
395
396 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
397 goto out;
398 nfrags = err;
399
400 assoclen = sizeof(*esph);
401 sglists = 1;
402 seqhilen = 0;
403
404 if (x->props.flags & XFRM_STATE_ESN) {
405 sglists += 2;
406 seqhilen += sizeof(__be32);
407 assoclen += seqhilen;
408 }
409
410 err = -ENOMEM;
411 tmp = esp_alloc_tmp(aead, nfrags + sglists, seqhilen);
412 if (!tmp)
413 goto out;
414
415 ESP_SKB_CB(skb)->tmp = tmp;
416 seqhi = esp_tmp_seqhi(tmp);
417 iv = esp_tmp_iv(aead, tmp, seqhilen);
418 req = esp_tmp_req(aead, iv);
419 asg = esp_req_sg(aead, req);
420 sg = asg + sglists;
421
422 skb->ip_summed = CHECKSUM_NONE;
423
424 esph = (struct ip_esp_hdr *)skb->data;
425
426 /* Get ivec. This can be wrong, check against another impls. */
427 iv = esph->enc_data;
428
429 sg_init_table(sg, nfrags);
430 skb_to_sgvec(skb, sg, sizeof(*esph) + crypto_aead_ivsize(aead), elen);
431
432 if ((x->props.flags & XFRM_STATE_ESN)) {
433 sg_init_table(asg, 3);
434 sg_set_buf(asg, &esph->spi, sizeof(__be32));
435 *seqhi = XFRM_SKB_CB(skb)->seq.input.hi;
436 sg_set_buf(asg + 1, seqhi, seqhilen);
437 sg_set_buf(asg + 2, &esph->seq_no, sizeof(__be32));
438 } else
439 sg_init_one(asg, esph, sizeof(*esph));
440
441 aead_request_set_callback(req, 0, esp_input_done, skb);
442 aead_request_set_crypt(req, sg, sg, elen, iv);
443 aead_request_set_assoc(req, asg, assoclen);
444
445 err = crypto_aead_decrypt(req);
446 if (err == -EINPROGRESS)
447 goto out;
448
449 err = esp_input_done2(skb, err);
450
451out:
452 return err;
453}
454
455static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
456{
457 struct esp_data *esp = x->data;
458 u32 blksize = ALIGN(crypto_aead_blocksize(esp->aead), 4);
459 u32 align = max_t(u32, blksize, esp->padlen);
460 u32 rem;
461
462 mtu -= x->props.header_len + crypto_aead_authsize(esp->aead);
463 rem = mtu & (align - 1);
464 mtu &= ~(align - 1);
465
466 switch (x->props.mode) {
467 case XFRM_MODE_TUNNEL:
468 break;
469 default:
470 case XFRM_MODE_TRANSPORT:
471 /* The worst case */
472 mtu -= blksize - 4;
473 mtu += min_t(u32, blksize - 4, rem);
474 break;
475 case XFRM_MODE_BEET:
476 /* The worst case. */
477 mtu += min_t(u32, IPV4_BEET_PHMAXLEN, rem);
478 break;
479 }
480
481 return mtu - 2;
482}
483
484static void esp4_err(struct sk_buff *skb, u32 info)
485{
486 struct net *net = dev_net(skb->dev);
487 const struct iphdr *iph = (const struct iphdr *)skb->data;
488 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
489 struct xfrm_state *x;
490
491 if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH ||
492 icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
493 return;
494
495 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
496 esph->spi, IPPROTO_ESP, AF_INET);
497 if (!x)
498 return;
499 NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
500 ntohl(esph->spi), ntohl(iph->daddr));
501 xfrm_state_put(x);
502}
503
504static void esp_destroy(struct xfrm_state *x)
505{
506 struct esp_data *esp = x->data;
507
508 if (!esp)
509 return;
510
511 crypto_free_aead(esp->aead);
512 kfree(esp);
513}
514
515static int esp_init_aead(struct xfrm_state *x)
516{
517 struct esp_data *esp = x->data;
518 struct crypto_aead *aead;
519 int err;
520
521 aead = crypto_alloc_aead(x->aead->alg_name, 0, 0);
522 err = PTR_ERR(aead);
523 if (IS_ERR(aead))
524 goto error;
525
526 esp->aead = aead;
527
528 err = crypto_aead_setkey(aead, x->aead->alg_key,
529 (x->aead->alg_key_len + 7) / 8);
530 if (err)
531 goto error;
532
533 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
534 if (err)
535 goto error;
536
537error:
538 return err;
539}
540
541static int esp_init_authenc(struct xfrm_state *x)
542{
543 struct esp_data *esp = x->data;
544 struct crypto_aead *aead;
545 struct crypto_authenc_key_param *param;
546 struct rtattr *rta;
547 char *key;
548 char *p;
549 char authenc_name[CRYPTO_MAX_ALG_NAME];
550 unsigned int keylen;
551 int err;
552
553 err = -EINVAL;
554 if (x->ealg == NULL)
555 goto error;
556
557 err = -ENAMETOOLONG;
558
559 if ((x->props.flags & XFRM_STATE_ESN)) {
560 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
561 "authencesn(%s,%s)",
562 x->aalg ? x->aalg->alg_name : "digest_null",
563 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
564 goto error;
565 } else {
566 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
567 "authenc(%s,%s)",
568 x->aalg ? x->aalg->alg_name : "digest_null",
569 x->ealg->alg_name) >= CRYPTO_MAX_ALG_NAME)
570 goto error;
571 }
572
573 aead = crypto_alloc_aead(authenc_name, 0, 0);
574 err = PTR_ERR(aead);
575 if (IS_ERR(aead))
576 goto error;
577
578 esp->aead = aead;
579
580 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
581 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
582 err = -ENOMEM;
583 key = kmalloc(keylen, GFP_KERNEL);
584 if (!key)
585 goto error;
586
587 p = key;
588 rta = (void *)p;
589 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
590 rta->rta_len = RTA_LENGTH(sizeof(*param));
591 param = RTA_DATA(rta);
592 p += RTA_SPACE(sizeof(*param));
593
594 if (x->aalg) {
595 struct xfrm_algo_desc *aalg_desc;
596
597 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
598 p += (x->aalg->alg_key_len + 7) / 8;
599
600 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
601 BUG_ON(!aalg_desc);
602
603 err = -EINVAL;
604 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
605 crypto_aead_authsize(aead)) {
606 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
607 x->aalg->alg_name,
608 crypto_aead_authsize(aead),
609 aalg_desc->uinfo.auth.icv_fullbits/8);
610 goto free_key;
611 }
612
613 err = crypto_aead_setauthsize(
614 aead, x->aalg->alg_trunc_len / 8);
615 if (err)
616 goto free_key;
617 }
618
619 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
620 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
621
622 err = crypto_aead_setkey(aead, key, keylen);
623
624free_key:
625 kfree(key);
626
627error:
628 return err;
629}
630
631static int esp_init_state(struct xfrm_state *x)
632{
633 struct esp_data *esp;
634 struct crypto_aead *aead;
635 u32 align;
636 int err;
637
638 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
639 if (esp == NULL)
640 return -ENOMEM;
641
642 x->data = esp;
643
644 if (x->aead)
645 err = esp_init_aead(x);
646 else
647 err = esp_init_authenc(x);
648
649 if (err)
650 goto error;
651
652 aead = esp->aead;
653
654 esp->padlen = 0;
655
656 x->props.header_len = sizeof(struct ip_esp_hdr) +
657 crypto_aead_ivsize(aead);
658 if (x->props.mode == XFRM_MODE_TUNNEL)
659 x->props.header_len += sizeof(struct iphdr);
660 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
661 x->props.header_len += IPV4_BEET_PHMAXLEN;
662 if (x->encap) {
663 struct xfrm_encap_tmpl *encap = x->encap;
664
665 switch (encap->encap_type) {
666 default:
667 goto error;
668 case UDP_ENCAP_ESPINUDP:
669 x->props.header_len += sizeof(struct udphdr);
670 break;
671 case UDP_ENCAP_ESPINUDP_NON_IKE:
672 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
673 break;
674 }
675 }
676
677 align = ALIGN(crypto_aead_blocksize(aead), 4);
678 if (esp->padlen)
679 align = max_t(u32, align, esp->padlen);
680 x->props.trailer_len = align + 1 + crypto_aead_authsize(esp->aead);
681
682error:
683 return err;
684}
685
686static const struct xfrm_type esp_type =
687{
688 .description = "ESP4",
689 .owner = THIS_MODULE,
690 .proto = IPPROTO_ESP,
691 .flags = XFRM_TYPE_REPLAY_PROT,
692 .init_state = esp_init_state,
693 .destructor = esp_destroy,
694 .get_mtu = esp4_get_mtu,
695 .input = esp_input,
696 .output = esp_output
697};
698
699static const struct net_protocol esp4_protocol = {
700 .handler = xfrm4_rcv,
701 .err_handler = esp4_err,
702 .no_policy = 1,
703 .netns_ok = 1,
704};
705
706static int __init esp4_init(void)
707{
708 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
709 printk(KERN_INFO "ip esp init: can't add xfrm type\n");
710 return -EAGAIN;
711 }
712 if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
713 printk(KERN_INFO "ip esp init: can't add protocol\n");
714 xfrm_unregister_type(&esp_type, AF_INET);
715 return -EAGAIN;
716 }
717 return 0;
718}
719
720static void __exit esp4_fini(void)
721{
722 if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
723 printk(KERN_INFO "ip esp close: can't remove protocol\n");
724 if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
725 printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
726}
727
728module_init(esp4_init);
729module_exit(esp4_fini);
730MODULE_LICENSE("GPL");
731MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);