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Merge tag 'io_uring-5.11-2021-01-16' of git://git.kernel.dk/linux-block
[linux/fpc-iii.git] / net / ipv4 / esp4.c
bloba3271ec3e1627fb4f6e29da0e0fb1a638fe7e789
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
24 #include <linux/highmem.h>
25
26 struct esp_skb_cb {
27 struct xfrm_skb_cb xfrm;
28 void *tmp;
29 };
30
31 struct esp_output_extra {
32 __be32 seqhi;
33 u32 esphoff;
34 };
35
36 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
37
38 /*
39 * Allocate an AEAD request structure with extra space for SG and IV.
40 *
41 * For alignment considerations the IV is placed at the front, followed
42 * by the request and finally the SG list.
43 *
44 * TODO: Use spare space in skb for this where possible.
45 */
46 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen)
47 {
48 unsigned int len;
49
50 len = extralen;
51
52 len += crypto_aead_ivsize(aead);
53
54 if (len) {
55 len += crypto_aead_alignmask(aead) &
56 ~(crypto_tfm_ctx_alignment() - 1);
57 len = ALIGN(len, crypto_tfm_ctx_alignment());
58 }
59
60 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
61 len = ALIGN(len, __alignof__(struct scatterlist));
62
63 len += sizeof(struct scatterlist) * nfrags;
64
65 return kmalloc(len, GFP_ATOMIC);
66 }
67
68 static inline void *esp_tmp_extra(void *tmp)
69 {
70 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
71 }
72
73 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen)
74 {
75 return crypto_aead_ivsize(aead) ?
76 PTR_ALIGN((u8 *)tmp + extralen,
77 crypto_aead_alignmask(aead) + 1) : tmp + extralen;
78 }
79
80 static 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
90 static 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
98 static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
99 {
100 struct esp_output_extra *extra = esp_tmp_extra(tmp);
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(*extra);
109
110 extra = esp_tmp_extra(tmp);
111 iv = esp_tmp_iv(aead, tmp, extralen);
112 req = esp_tmp_req(aead, iv);
113
114 /* Unref skb_frag_pages in the src scatterlist if necessary.
115 * Skip the first sg which comes from skb->data.
116 */
117 if (req->src != req->dst)
118 for (sg = sg_next(req->src); sg; sg = sg_next(sg))
119 put_page(sg_page(sg));
120 }
121
122 #ifdef CONFIG_INET_ESPINTCP
123 struct esp_tcp_sk {
124 struct sock *sk;
125 struct rcu_head rcu;
126 };
127
128 static 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
136 static struct sock *esp_find_tcp_sk(struct xfrm_state *x)
137 {
138 struct xfrm_encap_tmpl *encap = x->encap;
139 struct esp_tcp_sk *esk;
140 __be16 sport, dport;
141 struct sock *nsk;
142 struct sock *sk;
143
144 sk = rcu_dereference(x->encap_sk);
145 if (sk && sk->sk_state == TCP_ESTABLISHED)
146 return sk;
147
148 spin_lock_bh(&x->lock);
149 sport = encap->encap_sport;
150 dport = encap->encap_dport;
151 nsk = rcu_dereference_protected(x->encap_sk,
152 lockdep_is_held(&x->lock));
153 if (sk && sk == nsk) {
154 esk = kmalloc(sizeof(*esk), GFP_ATOMIC);
155 if (!esk) {
156 spin_unlock_bh(&x->lock);
157 return ERR_PTR(-ENOMEM);
158 }
159 RCU_INIT_POINTER(x->encap_sk, NULL);
160 esk->sk = sk;
161 call_rcu(&esk->rcu, esp_free_tcp_sk);
162 }
163 spin_unlock_bh(&x->lock);
164
165 sk = inet_lookup_established(xs_net(x), &tcp_hashinfo, x->id.daddr.a4,
166 dport, x->props.saddr.a4, sport, 0);
167 if (!sk)
168 return ERR_PTR(-ENOENT);
169
170 if (!tcp_is_ulp_esp(sk)) {
171 sock_put(sk);
172 return ERR_PTR(-EINVAL);
173 }
174
175 spin_lock_bh(&x->lock);
176 nsk = rcu_dereference_protected(x->encap_sk,
177 lockdep_is_held(&x->lock));
178 if (encap->encap_sport != sport ||
179 encap->encap_dport != dport) {
180 sock_put(sk);
181 sk = nsk ?: ERR_PTR(-EREMCHG);
182 } else if (sk == nsk) {
183 sock_put(sk);
184 } else {
185 rcu_assign_pointer(x->encap_sk, sk);
186 }
187 spin_unlock_bh(&x->lock);
188
189 return sk;
190 }
191
192 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
193 {
194 struct sock *sk;
195 int err;
196
197 rcu_read_lock();
198
199 sk = esp_find_tcp_sk(x);
200 err = PTR_ERR_OR_ZERO(sk);
201 if (err)
202 goto out;
203
204 bh_lock_sock(sk);
205 if (sock_owned_by_user(sk))
206 err = espintcp_queue_out(sk, skb);
207 else
208 err = espintcp_push_skb(sk, skb);
209 bh_unlock_sock(sk);
210
211 out:
212 rcu_read_unlock();
213 return err;
214 }
215
216 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
217 struct sk_buff *skb)
218 {
219 struct dst_entry *dst = skb_dst(skb);
220 struct xfrm_state *x = dst->xfrm;
221
222 return esp_output_tcp_finish(x, skb);
223 }
224
225 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
226 {
227 int err;
228
229 local_bh_disable();
230 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
231 local_bh_enable();
232
233 /* EINPROGRESS just happens to do the right thing. It
234 * actually means that the skb has been consumed and
235 * isn't coming back.
236 */
237 return err ?: -EINPROGRESS;
238 }
239 #else
240 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
241 {
242 kfree_skb(skb);
243
244 return -EOPNOTSUPP;
245 }
246 #endif
247
248 static void esp_output_done(struct crypto_async_request *base, int err)
249 {
250 struct sk_buff *skb = base->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);
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, err);
283 }
284 }
285
286 /* Move ESP header back into place. */
287 static 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
297 static 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
306 static 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 * accomodate 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
336 static void esp_output_done_esn(struct crypto_async_request *base, int err)
337 {
338 struct sk_buff *skb = base->data;
339
340 esp_output_restore_header(skb);
341 esp_output_done(base, err);
342 }
343
344 static 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 __be32 *udpdata32;
352 unsigned int len;
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 *skb_mac_header(skb) = IPPROTO_UDP;
365
366 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
367 udpdata32 = (__be32 *)(uh + 1);
368 udpdata32[0] = udpdata32[1] = 0;
369 return (struct ip_esp_hdr *)(udpdata32 + 2);
370 }
371
372 return (struct ip_esp_hdr *)(uh + 1);
373 }
374
375 #ifdef CONFIG_INET_ESPINTCP
376 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
377 struct sk_buff *skb,
378 struct esp_info *esp)
379 {
380 __be16 *lenp = (void *)esp->esph;
381 struct ip_esp_hdr *esph;
382 unsigned int len;
383 struct sock *sk;
384
385 len = skb->len + esp->tailen - skb_transport_offset(skb);
386 if (len > IP_MAX_MTU)
387 return ERR_PTR(-EMSGSIZE);
388
389 rcu_read_lock();
390 sk = esp_find_tcp_sk(x);
391 rcu_read_unlock();
392
393 if (IS_ERR(sk))
394 return ERR_CAST(sk);
395
396 *lenp = htons(len);
397 esph = (struct ip_esp_hdr *)(lenp + 1);
398
399 return esph;
400 }
401 #else
402 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
403 struct sk_buff *skb,
404 struct esp_info *esp)
405 {
406 return ERR_PTR(-EOPNOTSUPP);
407 }
408 #endif
409
410 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb,
411 struct esp_info *esp)
412 {
413 struct xfrm_encap_tmpl *encap = x->encap;
414 struct ip_esp_hdr *esph;
415 __be16 sport, dport;
416 int encap_type;
417
418 spin_lock_bh(&x->lock);
419 sport = encap->encap_sport;
420 dport = encap->encap_dport;
421 encap_type = encap->encap_type;
422 spin_unlock_bh(&x->lock);
423
424 switch (encap_type) {
425 default:
426 case UDP_ENCAP_ESPINUDP:
427 case UDP_ENCAP_ESPINUDP_NON_IKE:
428 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport);
429 break;
430 case TCP_ENCAP_ESPINTCP:
431 esph = esp_output_tcp_encap(x, skb, esp);
432 break;
433 }
434
435 if (IS_ERR(esph))
436 return PTR_ERR(esph);
437
438 esp->esph = esph;
439
440 return 0;
441 }
442
443 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
444 {
445 u8 *tail;
446 int nfrags;
447 int esph_offset;
448 struct page *page;
449 struct sk_buff *trailer;
450 int tailen = esp->tailen;
451
452 /* this is non-NULL only with TCP/UDP Encapsulation */
453 if (x->encap) {
454 int err = esp_output_encap(x, skb, esp);
455
456 if (err < 0)
457 return err;
458 }
459
460 if (!skb_cloned(skb)) {
461 if (tailen <= skb_tailroom(skb)) {
462 nfrags = 1;
463 trailer = skb;
464 tail = skb_tail_pointer(trailer);
465
466 goto skip_cow;
467 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
468 && !skb_has_frag_list(skb)) {
469 int allocsize;
470 struct sock *sk = skb->sk;
471 struct page_frag *pfrag = &x->xfrag;
472
473 esp->inplace = false;
474
475 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
476
477 spin_lock_bh(&x->lock);
478
479 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
480 spin_unlock_bh(&x->lock);
481 goto cow;
482 }
483
484 page = pfrag->page;
485 get_page(page);
486
487 tail = page_address(page) + pfrag->offset;
488
489 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
490
491 nfrags = skb_shinfo(skb)->nr_frags;
492
493 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
494 tailen);
495 skb_shinfo(skb)->nr_frags = ++nfrags;
496
497 pfrag->offset = pfrag->offset + allocsize;
498
499 spin_unlock_bh(&x->lock);
500
501 nfrags++;
502
503 skb->len += tailen;
504 skb->data_len += tailen;
505 skb->truesize += tailen;
506 if (sk && sk_fullsock(sk))
507 refcount_add(tailen, &sk->sk_wmem_alloc);
508
509 goto out;
510 }
511 }
512
513 cow:
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
522 skip_cow:
523 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
524 pskb_put(skb, trailer, tailen);
525
526 out:
527 return nfrags;
528 }
529 EXPORT_SYMBOL_GPL(esp_output_head);
530
531 int 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);
642
643 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
644 err = esp_output_tail_tcp(x, skb);
645
646 error_free:
647 kfree(tmp);
648 error:
649 return err;
650 }
651 EXPORT_SYMBOL_GPL(esp_output_tail);
652
653 static 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
703 static inline int esp_remove_trailer(struct sk_buff *skb)
704 {
705 struct xfrm_state *x = xfrm_input_state(skb);
706 struct xfrm_offload *xo = xfrm_offload(skb);
707 struct crypto_aead *aead = x->data;
708 int alen, hlen, elen;
709 int padlen, trimlen;
710 __wsum csumdiff;
711 u8 nexthdr[2];
712 int ret;
713
714 alen = crypto_aead_authsize(aead);
715 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
716 elen = skb->len - hlen;
717
718 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) {
719 ret = xo->proto;
720 goto out;
721 }
722
723 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
724 BUG();
725
726 ret = -EINVAL;
727 padlen = nexthdr[0];
728 if (padlen + 2 + alen >= elen) {
729 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
730 padlen + 2, elen - alen);
731 goto out;
732 }
733
734 trimlen = alen + padlen + 2;
735 if (skb->ip_summed == CHECKSUM_COMPLETE) {
736 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
737 skb->csum = csum_block_sub(skb->csum, csumdiff,
738 skb->len - trimlen);
739 }
740 pskb_trim(skb, skb->len - trimlen);
741
742 ret = nexthdr[1];
743
744 out:
745 return ret;
746 }
747
748 int esp_input_done2(struct sk_buff *skb, int err)
749 {
750 const struct iphdr *iph;
751 struct xfrm_state *x = xfrm_input_state(skb);
752 struct xfrm_offload *xo = xfrm_offload(skb);
753 struct crypto_aead *aead = x->data;
754 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
755 int ihl;
756
757 if (!xo || (xo && !(xo->flags & CRYPTO_DONE)))
758 kfree(ESP_SKB_CB(skb)->tmp);
759
760 if (unlikely(err))
761 goto out;
762
763 err = esp_remove_trailer(skb);
764 if (unlikely(err < 0))
765 goto out;
766
767 iph = ip_hdr(skb);
768 ihl = iph->ihl * 4;
769
770 if (x->encap) {
771 struct xfrm_encap_tmpl *encap = x->encap;
772 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl);
773 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
774 __be16 source;
775
776 switch (x->encap->encap_type) {
777 case TCP_ENCAP_ESPINTCP:
778 source = th->source;
779 break;
780 case UDP_ENCAP_ESPINUDP:
781 case UDP_ENCAP_ESPINUDP_NON_IKE:
782 source = uh->source;
783 break;
784 default:
785 WARN_ON_ONCE(1);
786 err = -EINVAL;
787 goto out;
788 }
789
790 /*
791 * 1) if the NAT-T peer's IP or port changed then
792 * advertize the change to the keying daemon.
793 * This is an inbound SA, so just compare
794 * SRC ports.
795 */
796 if (iph->saddr != x->props.saddr.a4 ||
797 source != encap->encap_sport) {
798 xfrm_address_t ipaddr;
799
800 ipaddr.a4 = iph->saddr;
801 km_new_mapping(x, &ipaddr, source);
802
803 /* XXX: perhaps add an extra
804 * policy check here, to see
805 * if we should allow or
806 * reject a packet from a
807 * different source
808 * address/port.
809 */
810 }
811
812 /*
813 * 2) ignore UDP/TCP checksums in case
814 * of NAT-T in Transport Mode, or
815 * perform other post-processing fixes
816 * as per draft-ietf-ipsec-udp-encaps-06,
817 * section 3.1.2
818 */
819 if (x->props.mode == XFRM_MODE_TRANSPORT)
820 skb->ip_summed = CHECKSUM_UNNECESSARY;
821 }
822
823 skb_pull_rcsum(skb, hlen);
824 if (x->props.mode == XFRM_MODE_TUNNEL)
825 skb_reset_transport_header(skb);
826 else
827 skb_set_transport_header(skb, -ihl);
828
829 /* RFC4303: Drop dummy packets without any error */
830 if (err == IPPROTO_NONE)
831 err = -EINVAL;
832
833 out:
834 return err;
835 }
836 EXPORT_SYMBOL_GPL(esp_input_done2);
837
838 static void esp_input_done(struct crypto_async_request *base, int err)
839 {
840 struct sk_buff *skb = base->data;
841
842 xfrm_input_resume(skb, esp_input_done2(skb, err));
843 }
844
845 static void esp_input_restore_header(struct sk_buff *skb)
846 {
847 esp_restore_header(skb, 0);
848 __skb_pull(skb, 4);
849 }
850
851 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
852 {
853 struct xfrm_state *x = xfrm_input_state(skb);
854 struct ip_esp_hdr *esph;
855
856 /* For ESN we move the header forward by 4 bytes to
857 * accomodate the high bits. We will move it back after
858 * decryption.
859 */
860 if ((x->props.flags & XFRM_STATE_ESN)) {
861 esph = skb_push(skb, 4);
862 *seqhi = esph->spi;
863 esph->spi = esph->seq_no;
864 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
865 }
866 }
867
868 static void esp_input_done_esn(struct crypto_async_request *base, int err)
869 {
870 struct sk_buff *skb = base->data;
871
872 esp_input_restore_header(skb);
873 esp_input_done(base, err);
874 }
875
876 /*
877 * Note: detecting truncated vs. non-truncated authentication data is very
878 * expensive, so we only support truncated data, which is the recommended
879 * and common case.
880 */
881 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
882 {
883 struct crypto_aead *aead = x->data;
884 struct aead_request *req;
885 struct sk_buff *trailer;
886 int ivlen = crypto_aead_ivsize(aead);
887 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
888 int nfrags;
889 int assoclen;
890 int seqhilen;
891 __be32 *seqhi;
892 void *tmp;
893 u8 *iv;
894 struct scatterlist *sg;
895 int err = -EINVAL;
896
897 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
898 goto out;
899
900 if (elen <= 0)
901 goto out;
902
903 assoclen = sizeof(struct ip_esp_hdr);
904 seqhilen = 0;
905
906 if (x->props.flags & XFRM_STATE_ESN) {
907 seqhilen += sizeof(__be32);
908 assoclen += seqhilen;
909 }
910
911 if (!skb_cloned(skb)) {
912 if (!skb_is_nonlinear(skb)) {
913 nfrags = 1;
914
915 goto skip_cow;
916 } else if (!skb_has_frag_list(skb)) {
917 nfrags = skb_shinfo(skb)->nr_frags;
918 nfrags++;
919
920 goto skip_cow;
921 }
922 }
923
924 err = skb_cow_data(skb, 0, &trailer);
925 if (err < 0)
926 goto out;
927
928 nfrags = err;
929
930 skip_cow:
931 err = -ENOMEM;
932 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
933 if (!tmp)
934 goto out;
935
936 ESP_SKB_CB(skb)->tmp = tmp;
937 seqhi = esp_tmp_extra(tmp);
938 iv = esp_tmp_iv(aead, tmp, seqhilen);
939 req = esp_tmp_req(aead, iv);
940 sg = esp_req_sg(aead, req);
941
942 esp_input_set_header(skb, seqhi);
943
944 sg_init_table(sg, nfrags);
945 err = skb_to_sgvec(skb, sg, 0, skb->len);
946 if (unlikely(err < 0)) {
947 kfree(tmp);
948 goto out;
949 }
950
951 skb->ip_summed = CHECKSUM_NONE;
952
953 if ((x->props.flags & XFRM_STATE_ESN))
954 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
955 else
956 aead_request_set_callback(req, 0, esp_input_done, skb);
957
958 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
959 aead_request_set_ad(req, assoclen);
960
961 err = crypto_aead_decrypt(req);
962 if (err == -EINPROGRESS)
963 goto out;
964
965 if ((x->props.flags & XFRM_STATE_ESN))
966 esp_input_restore_header(skb);
967
968 err = esp_input_done2(skb, err);
969
970 out:
971 return err;
972 }
973
974 static int esp4_err(struct sk_buff *skb, u32 info)
975 {
976 struct net *net = dev_net(skb->dev);
977 const struct iphdr *iph = (const struct iphdr *)skb->data;
978 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
979 struct xfrm_state *x;
980
981 switch (icmp_hdr(skb)->type) {
982 case ICMP_DEST_UNREACH:
983 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
984 return 0;
985 case ICMP_REDIRECT:
986 break;
987 default:
988 return 0;
989 }
990
991 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
992 esph->spi, IPPROTO_ESP, AF_INET);
993 if (!x)
994 return 0;
995
996 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
997 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP);
998 else
999 ipv4_redirect(skb, net, 0, IPPROTO_ESP);
1000 xfrm_state_put(x);
1001
1002 return 0;
1003 }
1004
1005 static void esp_destroy(struct xfrm_state *x)
1006 {
1007 struct crypto_aead *aead = x->data;
1008
1009 if (!aead)
1010 return;
1011
1012 crypto_free_aead(aead);
1013 }
1014
1015 static int esp_init_aead(struct xfrm_state *x)
1016 {
1017 char aead_name[CRYPTO_MAX_ALG_NAME];
1018 struct crypto_aead *aead;
1019 int err;
1020
1021 err = -ENAMETOOLONG;
1022 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1023 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
1024 goto error;
1025
1026 aead = crypto_alloc_aead(aead_name, 0, 0);
1027 err = PTR_ERR(aead);
1028 if (IS_ERR(aead))
1029 goto error;
1030
1031 x->data = aead;
1032
1033 err = crypto_aead_setkey(aead, x->aead->alg_key,
1034 (x->aead->alg_key_len + 7) / 8);
1035 if (err)
1036 goto error;
1037
1038 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1039 if (err)
1040 goto error;
1041
1042 error:
1043 return err;
1044 }
1045
1046 static int esp_init_authenc(struct xfrm_state *x)
1047 {
1048 struct crypto_aead *aead;
1049 struct crypto_authenc_key_param *param;
1050 struct rtattr *rta;
1051 char *key;
1052 char *p;
1053 char authenc_name[CRYPTO_MAX_ALG_NAME];
1054 unsigned int keylen;
1055 int err;
1056
1057 err = -EINVAL;
1058 if (!x->ealg)
1059 goto error;
1060
1061 err = -ENAMETOOLONG;
1062
1063 if ((x->props.flags & XFRM_STATE_ESN)) {
1064 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1065 "%s%sauthencesn(%s,%s)%s",
1066 x->geniv ?: "", x->geniv ? "(" : "",
1067 x->aalg ? x->aalg->alg_name : "digest_null",
1068 x->ealg->alg_name,
1069 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
1070 goto error;
1071 } else {
1072 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1073 "%s%sauthenc(%s,%s)%s",
1074 x->geniv ?: "", x->geniv ? "(" : "",
1075 x->aalg ? x->aalg->alg_name : "digest_null",
1076 x->ealg->alg_name,
1077 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
1078 goto error;
1079 }
1080
1081 aead = crypto_alloc_aead(authenc_name, 0, 0);
1082 err = PTR_ERR(aead);
1083 if (IS_ERR(aead))
1084 goto error;
1085
1086 x->data = aead;
1087
1088 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1089 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1090 err = -ENOMEM;
1091 key = kmalloc(keylen, GFP_KERNEL);
1092 if (!key)
1093 goto error;
1094
1095 p = key;
1096 rta = (void *)p;
1097 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1098 rta->rta_len = RTA_LENGTH(sizeof(*param));
1099 param = RTA_DATA(rta);
1100 p += RTA_SPACE(sizeof(*param));
1101
1102 if (x->aalg) {
1103 struct xfrm_algo_desc *aalg_desc;
1104
1105 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1106 p += (x->aalg->alg_key_len + 7) / 8;
1107
1108 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1109 BUG_ON(!aalg_desc);
1110
1111 err = -EINVAL;
1112 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1113 crypto_aead_authsize(aead)) {
1114 pr_info("ESP: %s digestsize %u != %hu\n",
1115 x->aalg->alg_name,
1116 crypto_aead_authsize(aead),
1117 aalg_desc->uinfo.auth.icv_fullbits / 8);
1118 goto free_key;
1119 }
1120
1121 err = crypto_aead_setauthsize(
1122 aead, x->aalg->alg_trunc_len / 8);
1123 if (err)
1124 goto free_key;
1125 }
1126
1127 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1128 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1129
1130 err = crypto_aead_setkey(aead, key, keylen);
1131
1132 free_key:
1133 kfree(key);
1134
1135 error:
1136 return err;
1137 }
1138
1139 static int esp_init_state(struct xfrm_state *x)
1140 {
1141 struct crypto_aead *aead;
1142 u32 align;
1143 int err;
1144
1145 x->data = NULL;
1146
1147 if (x->aead)
1148 err = esp_init_aead(x);
1149 else
1150 err = esp_init_authenc(x);
1151
1152 if (err)
1153 goto error;
1154
1155 aead = x->data;
1156
1157 x->props.header_len = sizeof(struct ip_esp_hdr) +
1158 crypto_aead_ivsize(aead);
1159 if (x->props.mode == XFRM_MODE_TUNNEL)
1160 x->props.header_len += sizeof(struct iphdr);
1161 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
1162 x->props.header_len += IPV4_BEET_PHMAXLEN;
1163 if (x->encap) {
1164 struct xfrm_encap_tmpl *encap = x->encap;
1165
1166 switch (encap->encap_type) {
1167 default:
1168 err = -EINVAL;
1169 goto error;
1170 case UDP_ENCAP_ESPINUDP:
1171 x->props.header_len += sizeof(struct udphdr);
1172 break;
1173 case UDP_ENCAP_ESPINUDP_NON_IKE:
1174 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
1175 break;
1176 #ifdef CONFIG_INET_ESPINTCP
1177 case TCP_ENCAP_ESPINTCP:
1178 /* only the length field, TCP encap is done by
1179 * the socket
1180 */
1181 x->props.header_len += 2;
1182 break;
1183 #endif
1184 }
1185 }
1186
1187 align = ALIGN(crypto_aead_blocksize(aead), 4);
1188 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1189
1190 error:
1191 return err;
1192 }
1193
1194 static int esp4_rcv_cb(struct sk_buff *skb, int err)
1195 {
1196 return 0;
1197 }
1198
1199 static const struct xfrm_type esp_type =
1200 {
1201 .description = "ESP4",
1202 .owner = THIS_MODULE,
1203 .proto = IPPROTO_ESP,
1204 .flags = XFRM_TYPE_REPLAY_PROT,
1205 .init_state = esp_init_state,
1206 .destructor = esp_destroy,
1207 .input = esp_input,
1208 .output = esp_output,
1209 };
1210
1211 static struct xfrm4_protocol esp4_protocol = {
1212 .handler = xfrm4_rcv,
1213 .input_handler = xfrm_input,
1214 .cb_handler = esp4_rcv_cb,
1215 .err_handler = esp4_err,
1216 .priority = 0,
1217 };
1218
1219 static int __init esp4_init(void)
1220 {
1221 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1222 pr_info("%s: can't add xfrm type\n", __func__);
1223 return -EAGAIN;
1224 }
1225 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1226 pr_info("%s: can't add protocol\n", __func__);
1227 xfrm_unregister_type(&esp_type, AF_INET);
1228 return -EAGAIN;
1229 }
1230 return 0;
1231 }
1232
1233 static void __exit esp4_fini(void)
1234 {
1235 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1236 pr_info("%s: can't remove protocol\n", __func__);
1237 xfrm_unregister_type(&esp_type, AF_INET);
1238 }
1239
1240 module_init(esp4_init);
1241 module_exit(esp4_fini);
1242 MODULE_LICENSE("GPL");
1243 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
Linux with added FPC-III support