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 */
esp_alloc_tmp(struct crypto_aead * aead,int nfrags,int seqihlen)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
esp_tmp_extra(void * tmp)85 static inline void *esp_tmp_extra(void *tmp)
86 {
87 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
88 }
89
esp_tmp_iv(struct crypto_aead * aead,void * tmp,int seqhilen)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
esp_tmp_req(struct crypto_aead * aead,u8 * iv)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
esp_req_sg(struct crypto_aead * aead,struct aead_request * req)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
esp_ssg_unref(struct xfrm_state * x,void * tmp)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
esp_free_tcp_sk(struct rcu_head * head)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
esp6_find_tcp_sk(struct xfrm_state * x)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
esp_output_tcp_finish(struct xfrm_state * x,struct sk_buff * skb)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
esp_output_tcp_encap_cb(struct net * net,struct sock * sk,struct sk_buff * skb)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
esp_output_tail_tcp(struct xfrm_state * x,struct sk_buff * skb)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
esp_output_tail_tcp(struct xfrm_state * x,struct sk_buff * skb)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
esp_output_encap_csum(struct sk_buff * skb)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
esp_output_done(struct crypto_async_request * base,int err)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, err);
318 }
319 }
320
321 /* Move ESP header back into place. */
esp_restore_header(struct sk_buff * skb,unsigned int offset)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
esp_output_restore_header(struct sk_buff * skb)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
esp_output_set_esn(struct sk_buff * skb,struct xfrm_state * x,struct ip_esp_hdr * esph,struct esp_output_extra * extra)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
esp_output_done_esn(struct crypto_async_request * base,int err)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
esp6_output_udp_encap(struct sk_buff * skb,int encap_type,struct esp_info * esp,__be16 sport,__be16 dport)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
esp6_output_tcp_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)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
esp6_output_tcp_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)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
esp6_output_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)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
esp6_output_head(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)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 (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
495 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
496 goto cow;
497
498 if (!skb_cloned(skb)) {
499 if (tailen <= skb_tailroom(skb)) {
500 nfrags = 1;
501 trailer = skb;
502 tail = skb_tail_pointer(trailer);
503
504 goto skip_cow;
505 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
506 && !skb_has_frag_list(skb)) {
507 int allocsize;
508 struct sock *sk = skb->sk;
509 struct page_frag *pfrag = &x->xfrag;
510
511 esp->inplace = false;
512
513 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
514
515 spin_lock_bh(&x->lock);
516
517 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
518 spin_unlock_bh(&x->lock);
519 goto cow;
520 }
521
522 page = pfrag->page;
523 get_page(page);
524
525 tail = page_address(page) + pfrag->offset;
526
527 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
528
529 nfrags = skb_shinfo(skb)->nr_frags;
530
531 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
532 tailen);
533 skb_shinfo(skb)->nr_frags = ++nfrags;
534
535 pfrag->offset = pfrag->offset + allocsize;
536
537 spin_unlock_bh(&x->lock);
538
539 nfrags++;
540
541 skb->len += tailen;
542 skb->data_len += tailen;
543 skb->truesize += tailen;
544 if (sk && sk_fullsock(sk))
545 refcount_add(tailen, &sk->sk_wmem_alloc);
546
547 goto out;
548 }
549 }
550
551 cow:
552 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
553
554 nfrags = skb_cow_data(skb, tailen, &trailer);
555 if (nfrags < 0)
556 goto out;
557 tail = skb_tail_pointer(trailer);
558 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
559
560 skip_cow:
561 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
562 pskb_put(skb, trailer, tailen);
563
564 out:
565 return nfrags;
566 }
567 EXPORT_SYMBOL_GPL(esp6_output_head);
568
esp6_output_tail(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)569 int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
570 {
571 u8 *iv;
572 int alen;
573 void *tmp;
574 int ivlen;
575 int assoclen;
576 int extralen;
577 struct page *page;
578 struct ip_esp_hdr *esph;
579 struct aead_request *req;
580 struct crypto_aead *aead;
581 struct scatterlist *sg, *dsg;
582 struct esp_output_extra *extra;
583 int err = -ENOMEM;
584
585 assoclen = sizeof(struct ip_esp_hdr);
586 extralen = 0;
587
588 if (x->props.flags & XFRM_STATE_ESN) {
589 extralen += sizeof(*extra);
590 assoclen += sizeof(__be32);
591 }
592
593 aead = x->data;
594 alen = crypto_aead_authsize(aead);
595 ivlen = crypto_aead_ivsize(aead);
596
597 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
598 if (!tmp)
599 goto error;
600
601 extra = esp_tmp_extra(tmp);
602 iv = esp_tmp_iv(aead, tmp, extralen);
603 req = esp_tmp_req(aead, iv);
604 sg = esp_req_sg(aead, req);
605
606 if (esp->inplace)
607 dsg = sg;
608 else
609 dsg = &sg[esp->nfrags];
610
611 esph = esp_output_set_esn(skb, x, esp->esph, extra);
612 esp->esph = esph;
613
614 sg_init_table(sg, esp->nfrags);
615 err = skb_to_sgvec(skb, sg,
616 (unsigned char *)esph - skb->data,
617 assoclen + ivlen + esp->clen + alen);
618 if (unlikely(err < 0))
619 goto error_free;
620
621 if (!esp->inplace) {
622 int allocsize;
623 struct page_frag *pfrag = &x->xfrag;
624
625 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
626
627 spin_lock_bh(&x->lock);
628 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
629 spin_unlock_bh(&x->lock);
630 goto error_free;
631 }
632
633 skb_shinfo(skb)->nr_frags = 1;
634
635 page = pfrag->page;
636 get_page(page);
637 /* replace page frags in skb with new page */
638 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
639 pfrag->offset = pfrag->offset + allocsize;
640 spin_unlock_bh(&x->lock);
641
642 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
643 err = skb_to_sgvec(skb, dsg,
644 (unsigned char *)esph - skb->data,
645 assoclen + ivlen + esp->clen + alen);
646 if (unlikely(err < 0))
647 goto error_free;
648 }
649
650 if ((x->props.flags & XFRM_STATE_ESN))
651 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
652 else
653 aead_request_set_callback(req, 0, esp_output_done, skb);
654
655 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
656 aead_request_set_ad(req, assoclen);
657
658 memset(iv, 0, ivlen);
659 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
660 min(ivlen, 8));
661
662 ESP_SKB_CB(skb)->tmp = tmp;
663 err = crypto_aead_encrypt(req);
664
665 switch (err) {
666 case -EINPROGRESS:
667 goto error;
668
669 case -ENOSPC:
670 err = NET_XMIT_DROP;
671 break;
672
673 case 0:
674 if ((x->props.flags & XFRM_STATE_ESN))
675 esp_output_restore_header(skb);
676 esp_output_encap_csum(skb);
677 }
678
679 if (sg != dsg)
680 esp_ssg_unref(x, tmp);
681
682 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
683 err = esp_output_tail_tcp(x, skb);
684
685 error_free:
686 kfree(tmp);
687 error:
688 return err;
689 }
690 EXPORT_SYMBOL_GPL(esp6_output_tail);
691
esp6_output(struct xfrm_state * x,struct sk_buff * skb)692 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
693 {
694 int alen;
695 int blksize;
696 struct ip_esp_hdr *esph;
697 struct crypto_aead *aead;
698 struct esp_info esp;
699
700 esp.inplace = true;
701
702 esp.proto = *skb_mac_header(skb);
703 *skb_mac_header(skb) = IPPROTO_ESP;
704
705 /* skb is pure payload to encrypt */
706
707 aead = x->data;
708 alen = crypto_aead_authsize(aead);
709
710 esp.tfclen = 0;
711 if (x->tfcpad) {
712 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
713 u32 padto;
714
715 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
716 if (skb->len < padto)
717 esp.tfclen = padto - skb->len;
718 }
719 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
720 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
721 esp.plen = esp.clen - skb->len - esp.tfclen;
722 esp.tailen = esp.tfclen + esp.plen + alen;
723
724 esp.esph = ip_esp_hdr(skb);
725
726 esp.nfrags = esp6_output_head(x, skb, &esp);
727 if (esp.nfrags < 0)
728 return esp.nfrags;
729
730 esph = esp.esph;
731 esph->spi = x->id.spi;
732
733 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
734 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
735 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
736
737 skb_push(skb, -skb_network_offset(skb));
738
739 return esp6_output_tail(x, skb, &esp);
740 }
741
esp_remove_trailer(struct sk_buff * skb)742 static inline int esp_remove_trailer(struct sk_buff *skb)
743 {
744 struct xfrm_state *x = xfrm_input_state(skb);
745 struct xfrm_offload *xo = xfrm_offload(skb);
746 struct crypto_aead *aead = x->data;
747 int alen, hlen, elen;
748 int padlen, trimlen;
749 __wsum csumdiff;
750 u8 nexthdr[2];
751 int ret;
752
753 alen = crypto_aead_authsize(aead);
754 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
755 elen = skb->len - hlen;
756
757 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) {
758 ret = xo->proto;
759 goto out;
760 }
761
762 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2);
763 BUG_ON(ret);
764
765 ret = -EINVAL;
766 padlen = nexthdr[0];
767 if (padlen + 2 + alen >= elen) {
768 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
769 padlen + 2, elen - alen);
770 goto out;
771 }
772
773 trimlen = alen + padlen + 2;
774 if (skb->ip_summed == CHECKSUM_COMPLETE) {
775 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
776 skb->csum = csum_block_sub(skb->csum, csumdiff,
777 skb->len - trimlen);
778 }
779 ret = pskb_trim(skb, skb->len - trimlen);
780 if (unlikely(ret))
781 return ret;
782
783 ret = nexthdr[1];
784
785 out:
786 return ret;
787 }
788
esp6_input_done2(struct sk_buff * skb,int err)789 int esp6_input_done2(struct sk_buff *skb, int err)
790 {
791 struct xfrm_state *x = xfrm_input_state(skb);
792 struct xfrm_offload *xo = xfrm_offload(skb);
793 struct crypto_aead *aead = x->data;
794 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
795 int hdr_len = skb_network_header_len(skb);
796
797 if (!xo || !(xo->flags & CRYPTO_DONE))
798 kfree(ESP_SKB_CB(skb)->tmp);
799
800 if (unlikely(err))
801 goto out;
802
803 err = esp_remove_trailer(skb);
804 if (unlikely(err < 0))
805 goto out;
806
807 if (x->encap) {
808 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
809 int offset = skb_network_offset(skb) + sizeof(*ip6h);
810 struct xfrm_encap_tmpl *encap = x->encap;
811 u8 nexthdr = ip6h->nexthdr;
812 __be16 frag_off, source;
813 struct udphdr *uh;
814 struct tcphdr *th;
815
816 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
817 if (offset == -1) {
818 err = -EINVAL;
819 goto out;
820 }
821
822 uh = (void *)(skb->data + offset);
823 th = (void *)(skb->data + offset);
824 hdr_len += offset;
825
826 switch (x->encap->encap_type) {
827 case TCP_ENCAP_ESPINTCP:
828 source = th->source;
829 break;
830 case UDP_ENCAP_ESPINUDP:
831 case UDP_ENCAP_ESPINUDP_NON_IKE:
832 source = uh->source;
833 break;
834 default:
835 WARN_ON_ONCE(1);
836 err = -EINVAL;
837 goto out;
838 }
839
840 /*
841 * 1) if the NAT-T peer's IP or port changed then
842 * advertize the change to the keying daemon.
843 * This is an inbound SA, so just compare
844 * SRC ports.
845 */
846 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) ||
847 source != encap->encap_sport) {
848 xfrm_address_t ipaddr;
849
850 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6));
851 km_new_mapping(x, &ipaddr, source);
852
853 /* XXX: perhaps add an extra
854 * policy check here, to see
855 * if we should allow or
856 * reject a packet from a
857 * different source
858 * address/port.
859 */
860 }
861
862 /*
863 * 2) ignore UDP/TCP checksums in case
864 * of NAT-T in Transport Mode, or
865 * perform other post-processing fixes
866 * as per draft-ietf-ipsec-udp-encaps-06,
867 * section 3.1.2
868 */
869 if (x->props.mode == XFRM_MODE_TRANSPORT)
870 skb->ip_summed = CHECKSUM_UNNECESSARY;
871 }
872
873 skb_postpull_rcsum(skb, skb_network_header(skb),
874 skb_network_header_len(skb));
875 skb_pull_rcsum(skb, hlen);
876 if (x->props.mode == XFRM_MODE_TUNNEL)
877 skb_reset_transport_header(skb);
878 else
879 skb_set_transport_header(skb, -hdr_len);
880
881 /* RFC4303: Drop dummy packets without any error */
882 if (err == IPPROTO_NONE)
883 err = -EINVAL;
884
885 out:
886 return err;
887 }
888 EXPORT_SYMBOL_GPL(esp6_input_done2);
889
esp_input_done(struct crypto_async_request * base,int err)890 static void esp_input_done(struct crypto_async_request *base, int err)
891 {
892 struct sk_buff *skb = base->data;
893
894 xfrm_input_resume(skb, esp6_input_done2(skb, err));
895 }
896
esp_input_restore_header(struct sk_buff * skb)897 static void esp_input_restore_header(struct sk_buff *skb)
898 {
899 esp_restore_header(skb, 0);
900 __skb_pull(skb, 4);
901 }
902
esp_input_set_header(struct sk_buff * skb,__be32 * seqhi)903 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
904 {
905 struct xfrm_state *x = xfrm_input_state(skb);
906
907 /* For ESN we move the header forward by 4 bytes to
908 * accomodate the high bits. We will move it back after
909 * decryption.
910 */
911 if ((x->props.flags & XFRM_STATE_ESN)) {
912 struct ip_esp_hdr *esph = skb_push(skb, 4);
913
914 *seqhi = esph->spi;
915 esph->spi = esph->seq_no;
916 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
917 }
918 }
919
esp_input_done_esn(struct crypto_async_request * base,int err)920 static void esp_input_done_esn(struct crypto_async_request *base, int err)
921 {
922 struct sk_buff *skb = base->data;
923
924 esp_input_restore_header(skb);
925 esp_input_done(base, err);
926 }
927
esp6_input(struct xfrm_state * x,struct sk_buff * skb)928 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
929 {
930 struct crypto_aead *aead = x->data;
931 struct aead_request *req;
932 struct sk_buff *trailer;
933 int ivlen = crypto_aead_ivsize(aead);
934 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
935 int nfrags;
936 int assoclen;
937 int seqhilen;
938 int ret = 0;
939 void *tmp;
940 __be32 *seqhi;
941 u8 *iv;
942 struct scatterlist *sg;
943
944 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) {
945 ret = -EINVAL;
946 goto out;
947 }
948
949 if (elen <= 0) {
950 ret = -EINVAL;
951 goto out;
952 }
953
954 assoclen = sizeof(struct ip_esp_hdr);
955 seqhilen = 0;
956
957 if (x->props.flags & XFRM_STATE_ESN) {
958 seqhilen += sizeof(__be32);
959 assoclen += seqhilen;
960 }
961
962 if (!skb_cloned(skb)) {
963 if (!skb_is_nonlinear(skb)) {
964 nfrags = 1;
965
966 goto skip_cow;
967 } else if (!skb_has_frag_list(skb)) {
968 nfrags = skb_shinfo(skb)->nr_frags;
969 nfrags++;
970
971 goto skip_cow;
972 }
973 }
974
975 nfrags = skb_cow_data(skb, 0, &trailer);
976 if (nfrags < 0) {
977 ret = -EINVAL;
978 goto out;
979 }
980
981 skip_cow:
982 ret = -ENOMEM;
983 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
984 if (!tmp)
985 goto out;
986
987 ESP_SKB_CB(skb)->tmp = tmp;
988 seqhi = esp_tmp_extra(tmp);
989 iv = esp_tmp_iv(aead, tmp, seqhilen);
990 req = esp_tmp_req(aead, iv);
991 sg = esp_req_sg(aead, req);
992
993 esp_input_set_header(skb, seqhi);
994
995 sg_init_table(sg, nfrags);
996 ret = skb_to_sgvec(skb, sg, 0, skb->len);
997 if (unlikely(ret < 0)) {
998 kfree(tmp);
999 goto out;
1000 }
1001
1002 skb->ip_summed = CHECKSUM_NONE;
1003
1004 if ((x->props.flags & XFRM_STATE_ESN))
1005 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
1006 else
1007 aead_request_set_callback(req, 0, esp_input_done, skb);
1008
1009 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
1010 aead_request_set_ad(req, assoclen);
1011
1012 ret = crypto_aead_decrypt(req);
1013 if (ret == -EINPROGRESS)
1014 goto out;
1015
1016 if ((x->props.flags & XFRM_STATE_ESN))
1017 esp_input_restore_header(skb);
1018
1019 ret = esp6_input_done2(skb, ret);
1020
1021 out:
1022 return ret;
1023 }
1024
esp6_err(struct sk_buff * skb,struct inet6_skb_parm * opt,u8 type,u8 code,int offset,__be32 info)1025 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
1026 u8 type, u8 code, int offset, __be32 info)
1027 {
1028 struct net *net = dev_net(skb->dev);
1029 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
1030 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
1031 struct xfrm_state *x;
1032
1033 if (type != ICMPV6_PKT_TOOBIG &&
1034 type != NDISC_REDIRECT)
1035 return 0;
1036
1037 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
1038 esph->spi, IPPROTO_ESP, AF_INET6);
1039 if (!x)
1040 return 0;
1041
1042 if (type == NDISC_REDIRECT)
1043 ip6_redirect(skb, net, skb->dev->ifindex, 0,
1044 sock_net_uid(net, NULL));
1045 else
1046 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
1047 xfrm_state_put(x);
1048
1049 return 0;
1050 }
1051
esp6_destroy(struct xfrm_state * x)1052 static void esp6_destroy(struct xfrm_state *x)
1053 {
1054 struct crypto_aead *aead = x->data;
1055
1056 if (!aead)
1057 return;
1058
1059 crypto_free_aead(aead);
1060 }
1061
esp_init_aead(struct xfrm_state * x)1062 static int esp_init_aead(struct xfrm_state *x)
1063 {
1064 char aead_name[CRYPTO_MAX_ALG_NAME];
1065 struct crypto_aead *aead;
1066 int err;
1067
1068 err = -ENAMETOOLONG;
1069 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1070 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
1071 goto error;
1072
1073 aead = crypto_alloc_aead(aead_name, 0, 0);
1074 err = PTR_ERR(aead);
1075 if (IS_ERR(aead))
1076 goto error;
1077
1078 x->data = aead;
1079
1080 err = crypto_aead_setkey(aead, x->aead->alg_key,
1081 (x->aead->alg_key_len + 7) / 8);
1082 if (err)
1083 goto error;
1084
1085 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1086 if (err)
1087 goto error;
1088
1089 error:
1090 return err;
1091 }
1092
esp_init_authenc(struct xfrm_state * x)1093 static int esp_init_authenc(struct xfrm_state *x)
1094 {
1095 struct crypto_aead *aead;
1096 struct crypto_authenc_key_param *param;
1097 struct rtattr *rta;
1098 char *key;
1099 char *p;
1100 char authenc_name[CRYPTO_MAX_ALG_NAME];
1101 unsigned int keylen;
1102 int err;
1103
1104 err = -EINVAL;
1105 if (!x->ealg)
1106 goto error;
1107
1108 err = -ENAMETOOLONG;
1109
1110 if ((x->props.flags & XFRM_STATE_ESN)) {
1111 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1112 "%s%sauthencesn(%s,%s)%s",
1113 x->geniv ?: "", x->geniv ? "(" : "",
1114 x->aalg ? x->aalg->alg_name : "digest_null",
1115 x->ealg->alg_name,
1116 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
1117 goto error;
1118 } else {
1119 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1120 "%s%sauthenc(%s,%s)%s",
1121 x->geniv ?: "", x->geniv ? "(" : "",
1122 x->aalg ? x->aalg->alg_name : "digest_null",
1123 x->ealg->alg_name,
1124 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
1125 goto error;
1126 }
1127
1128 aead = crypto_alloc_aead(authenc_name, 0, 0);
1129 err = PTR_ERR(aead);
1130 if (IS_ERR(aead))
1131 goto error;
1132
1133 x->data = aead;
1134
1135 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1136 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1137 err = -ENOMEM;
1138 key = kmalloc(keylen, GFP_KERNEL);
1139 if (!key)
1140 goto error;
1141
1142 p = key;
1143 rta = (void *)p;
1144 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1145 rta->rta_len = RTA_LENGTH(sizeof(*param));
1146 param = RTA_DATA(rta);
1147 p += RTA_SPACE(sizeof(*param));
1148
1149 if (x->aalg) {
1150 struct xfrm_algo_desc *aalg_desc;
1151
1152 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1153 p += (x->aalg->alg_key_len + 7) / 8;
1154
1155 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1156 BUG_ON(!aalg_desc);
1157
1158 err = -EINVAL;
1159 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1160 crypto_aead_authsize(aead)) {
1161 pr_info("ESP: %s digestsize %u != %u\n",
1162 x->aalg->alg_name,
1163 crypto_aead_authsize(aead),
1164 aalg_desc->uinfo.auth.icv_fullbits / 8);
1165 goto free_key;
1166 }
1167
1168 err = crypto_aead_setauthsize(
1169 aead, x->aalg->alg_trunc_len / 8);
1170 if (err)
1171 goto free_key;
1172 }
1173
1174 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1175 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1176
1177 err = crypto_aead_setkey(aead, key, keylen);
1178
1179 free_key:
1180 kfree(key);
1181
1182 error:
1183 return err;
1184 }
1185
esp6_init_state(struct xfrm_state * x)1186 static int esp6_init_state(struct xfrm_state *x)
1187 {
1188 struct crypto_aead *aead;
1189 u32 align;
1190 int err;
1191
1192 x->data = NULL;
1193
1194 if (x->aead)
1195 err = esp_init_aead(x);
1196 else
1197 err = esp_init_authenc(x);
1198
1199 if (err)
1200 goto error;
1201
1202 aead = x->data;
1203
1204 x->props.header_len = sizeof(struct ip_esp_hdr) +
1205 crypto_aead_ivsize(aead);
1206 switch (x->props.mode) {
1207 case XFRM_MODE_BEET:
1208 if (x->sel.family != AF_INET6)
1209 x->props.header_len += IPV4_BEET_PHMAXLEN +
1210 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
1211 break;
1212 default:
1213 case XFRM_MODE_TRANSPORT:
1214 break;
1215 case XFRM_MODE_TUNNEL:
1216 x->props.header_len += sizeof(struct ipv6hdr);
1217 break;
1218 }
1219
1220 if (x->encap) {
1221 struct xfrm_encap_tmpl *encap = x->encap;
1222
1223 switch (encap->encap_type) {
1224 default:
1225 err = -EINVAL;
1226 goto error;
1227 case UDP_ENCAP_ESPINUDP:
1228 x->props.header_len += sizeof(struct udphdr);
1229 break;
1230 case UDP_ENCAP_ESPINUDP_NON_IKE:
1231 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
1232 break;
1233 #ifdef CONFIG_INET6_ESPINTCP
1234 case TCP_ENCAP_ESPINTCP:
1235 /* only the length field, TCP encap is done by
1236 * the socket
1237 */
1238 x->props.header_len += 2;
1239 break;
1240 #endif
1241 }
1242 }
1243
1244 align = ALIGN(crypto_aead_blocksize(aead), 4);
1245 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1246
1247 error:
1248 return err;
1249 }
1250
esp6_rcv_cb(struct sk_buff * skb,int err)1251 static int esp6_rcv_cb(struct sk_buff *skb, int err)
1252 {
1253 return 0;
1254 }
1255
1256 static const struct xfrm_type esp6_type = {
1257 .owner = THIS_MODULE,
1258 .proto = IPPROTO_ESP,
1259 .flags = XFRM_TYPE_REPLAY_PROT,
1260 .init_state = esp6_init_state,
1261 .destructor = esp6_destroy,
1262 .input = esp6_input,
1263 .output = esp6_output,
1264 };
1265
1266 static struct xfrm6_protocol esp6_protocol = {
1267 .handler = xfrm6_rcv,
1268 .input_handler = xfrm_input,
1269 .cb_handler = esp6_rcv_cb,
1270 .err_handler = esp6_err,
1271 .priority = 0,
1272 };
1273
esp6_init(void)1274 static int __init esp6_init(void)
1275 {
1276 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
1277 pr_info("%s: can't add xfrm type\n", __func__);
1278 return -EAGAIN;
1279 }
1280 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) {
1281 pr_info("%s: can't add protocol\n", __func__);
1282 xfrm_unregister_type(&esp6_type, AF_INET6);
1283 return -EAGAIN;
1284 }
1285
1286 return 0;
1287 }
1288
esp6_fini(void)1289 static void __exit esp6_fini(void)
1290 {
1291 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0)
1292 pr_info("%s: can't remove protocol\n", __func__);
1293 xfrm_unregister_type(&esp6_type, AF_INET6);
1294 }
1295
1296 module_init(esp6_init);
1297 module_exit(esp6_fini);
1298
1299 MODULE_LICENSE("GPL");
1300 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
1301