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,struct sk_buff * skb)115 static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb)
116 {
117 struct crypto_aead *aead = x->data;
118 int extralen = 0;
119 u8 *iv;
120 struct aead_request *req;
121 struct scatterlist *sg;
122
123 if (x->props.flags & XFRM_STATE_ESN)
124 extralen += sizeof(struct esp_output_extra);
125
126 iv = esp_tmp_iv(aead, tmp, extralen);
127 req = esp_tmp_req(aead, iv);
128
129 /* Unref skb_frag_pages in the src scatterlist if necessary.
130 * Skip the first sg which comes from skb->data.
131 */
132 if (req->src != req->dst)
133 for (sg = sg_next(req->src); sg; sg = sg_next(sg))
134 skb_page_unref(skb, sg_page(sg), false);
135 }
136
137 #ifdef CONFIG_INET6_ESPINTCP
138 struct esp_tcp_sk {
139 struct sock *sk;
140 struct rcu_head rcu;
141 };
142
esp_free_tcp_sk(struct rcu_head * head)143 static void esp_free_tcp_sk(struct rcu_head *head)
144 {
145 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu);
146
147 sock_put(esk->sk);
148 kfree(esk);
149 }
150
esp6_find_tcp_sk(struct xfrm_state * x)151 static struct sock *esp6_find_tcp_sk(struct xfrm_state *x)
152 {
153 struct xfrm_encap_tmpl *encap = x->encap;
154 struct net *net = xs_net(x);
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(net, net->ipv4.tcp_death_row.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 WARN_ON(1);
259 return -EOPNOTSUPP;
260 }
261 #endif
262
esp_output_encap_csum(struct sk_buff * skb)263 static void esp_output_encap_csum(struct sk_buff *skb)
264 {
265 /* UDP encap with IPv6 requires a valid checksum */
266 if (*skb_mac_header(skb) == IPPROTO_UDP) {
267 struct udphdr *uh = udp_hdr(skb);
268 struct ipv6hdr *ip6h = ipv6_hdr(skb);
269 int len = ntohs(uh->len);
270 unsigned int offset = skb_transport_offset(skb);
271 __wsum csum = skb_checksum(skb, offset, skb->len - offset, 0);
272
273 uh->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
274 len, IPPROTO_UDP, csum);
275 if (uh->check == 0)
276 uh->check = CSUM_MANGLED_0;
277 }
278 }
279
esp_output_done(void * data,int err)280 static void esp_output_done(void *data, int err)
281 {
282 struct sk_buff *skb = data;
283 struct xfrm_offload *xo = xfrm_offload(skb);
284 void *tmp;
285 struct xfrm_state *x;
286
287 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
288 struct sec_path *sp = skb_sec_path(skb);
289
290 x = sp->xvec[sp->len - 1];
291 } else {
292 x = skb_dst(skb)->xfrm;
293 }
294
295 tmp = ESP_SKB_CB(skb)->tmp;
296 esp_ssg_unref(x, tmp, skb);
297 kfree(tmp);
298
299 esp_output_encap_csum(skb);
300
301 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
302 if (err) {
303 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
304 kfree_skb(skb);
305 return;
306 }
307
308 skb_push(skb, skb->data - skb_mac_header(skb));
309 secpath_reset(skb);
310 xfrm_dev_resume(skb);
311 } else {
312 if (!err &&
313 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
314 esp_output_tail_tcp(x, skb);
315 else
316 xfrm_output_resume(skb->sk, skb, err);
317 }
318 }
319
320 /* Move ESP header back into place. */
esp_restore_header(struct sk_buff * skb,unsigned int offset)321 static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
322 {
323 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
324 void *tmp = ESP_SKB_CB(skb)->tmp;
325 __be32 *seqhi = esp_tmp_extra(tmp);
326
327 esph->seq_no = esph->spi;
328 esph->spi = *seqhi;
329 }
330
esp_output_restore_header(struct sk_buff * skb)331 static void esp_output_restore_header(struct sk_buff *skb)
332 {
333 void *tmp = ESP_SKB_CB(skb)->tmp;
334 struct esp_output_extra *extra = esp_tmp_extra(tmp);
335
336 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
337 sizeof(__be32));
338 }
339
esp_output_set_esn(struct sk_buff * skb,struct xfrm_state * x,struct ip_esp_hdr * esph,struct esp_output_extra * extra)340 static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb,
341 struct xfrm_state *x,
342 struct ip_esp_hdr *esph,
343 struct esp_output_extra *extra)
344 {
345 /* For ESN we move the header forward by 4 bytes to
346 * accommodate the high bits. We will move it back after
347 * encryption.
348 */
349 if ((x->props.flags & XFRM_STATE_ESN)) {
350 __u32 seqhi;
351 struct xfrm_offload *xo = xfrm_offload(skb);
352
353 if (xo)
354 seqhi = xo->seq.hi;
355 else
356 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
357
358 extra->esphoff = (unsigned char *)esph -
359 skb_transport_header(skb);
360 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
361 extra->seqhi = esph->spi;
362 esph->seq_no = htonl(seqhi);
363 }
364
365 esph->spi = x->id.spi;
366
367 return esph;
368 }
369
esp_output_done_esn(void * data,int err)370 static void esp_output_done_esn(void *data, int err)
371 {
372 struct sk_buff *skb = data;
373
374 esp_output_restore_header(skb);
375 esp_output_done(data, err);
376 }
377
esp6_output_udp_encap(struct sk_buff * skb,int encap_type,struct esp_info * esp,__be16 sport,__be16 dport)378 static struct ip_esp_hdr *esp6_output_udp_encap(struct sk_buff *skb,
379 int encap_type,
380 struct esp_info *esp,
381 __be16 sport,
382 __be16 dport)
383 {
384 struct udphdr *uh;
385 __be32 *udpdata32;
386 unsigned int len;
387
388 len = skb->len + esp->tailen - skb_transport_offset(skb);
389 if (len > U16_MAX)
390 return ERR_PTR(-EMSGSIZE);
391
392 uh = (struct udphdr *)esp->esph;
393 uh->source = sport;
394 uh->dest = dport;
395 uh->len = htons(len);
396 uh->check = 0;
397
398 *skb_mac_header(skb) = IPPROTO_UDP;
399
400 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
401 udpdata32 = (__be32 *)(uh + 1);
402 udpdata32[0] = udpdata32[1] = 0;
403 return (struct ip_esp_hdr *)(udpdata32 + 2);
404 }
405
406 return (struct ip_esp_hdr *)(uh + 1);
407 }
408
409 #ifdef CONFIG_INET6_ESPINTCP
esp6_output_tcp_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)410 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x,
411 struct sk_buff *skb,
412 struct esp_info *esp)
413 {
414 __be16 *lenp = (void *)esp->esph;
415 struct ip_esp_hdr *esph;
416 unsigned int len;
417 struct sock *sk;
418
419 len = skb->len + esp->tailen - skb_transport_offset(skb);
420 if (len > IP_MAX_MTU)
421 return ERR_PTR(-EMSGSIZE);
422
423 rcu_read_lock();
424 sk = esp6_find_tcp_sk(x);
425 rcu_read_unlock();
426
427 if (IS_ERR(sk))
428 return ERR_CAST(sk);
429
430 *lenp = htons(len);
431 esph = (struct ip_esp_hdr *)(lenp + 1);
432
433 return esph;
434 }
435 #else
esp6_output_tcp_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)436 static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x,
437 struct sk_buff *skb,
438 struct esp_info *esp)
439 {
440 return ERR_PTR(-EOPNOTSUPP);
441 }
442 #endif
443
esp6_output_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)444 static int esp6_output_encap(struct xfrm_state *x, struct sk_buff *skb,
445 struct esp_info *esp)
446 {
447 struct xfrm_encap_tmpl *encap = x->encap;
448 struct ip_esp_hdr *esph;
449 __be16 sport, dport;
450 int encap_type;
451
452 spin_lock_bh(&x->lock);
453 sport = encap->encap_sport;
454 dport = encap->encap_dport;
455 encap_type = encap->encap_type;
456 spin_unlock_bh(&x->lock);
457
458 switch (encap_type) {
459 default:
460 case UDP_ENCAP_ESPINUDP:
461 case UDP_ENCAP_ESPINUDP_NON_IKE:
462 esph = esp6_output_udp_encap(skb, encap_type, esp, sport, dport);
463 break;
464 case TCP_ENCAP_ESPINTCP:
465 esph = esp6_output_tcp_encap(x, skb, esp);
466 break;
467 }
468
469 if (IS_ERR(esph))
470 return PTR_ERR(esph);
471
472 esp->esph = esph;
473
474 return 0;
475 }
476
esp6_output_head(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)477 int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
478 {
479 u8 *tail;
480 int nfrags;
481 int esph_offset;
482 struct page *page;
483 struct sk_buff *trailer;
484 int tailen = esp->tailen;
485
486 if (x->encap) {
487 int err = esp6_output_encap(x, skb, esp);
488
489 if (err < 0)
490 return err;
491 }
492
493 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
494 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
495 goto cow;
496
497 if (!skb_cloned(skb)) {
498 if (tailen <= skb_tailroom(skb)) {
499 nfrags = 1;
500 trailer = skb;
501 tail = skb_tail_pointer(trailer);
502
503 goto skip_cow;
504 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
505 && !skb_has_frag_list(skb)) {
506 int allocsize;
507 struct sock *sk = skb->sk;
508 struct page_frag *pfrag = &x->xfrag;
509
510 esp->inplace = false;
511
512 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
513
514 spin_lock_bh(&x->lock);
515
516 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
517 spin_unlock_bh(&x->lock);
518 goto cow;
519 }
520
521 page = pfrag->page;
522 get_page(page);
523
524 tail = page_address(page) + pfrag->offset;
525
526 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
527
528 nfrags = skb_shinfo(skb)->nr_frags;
529
530 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
531 tailen);
532 skb_shinfo(skb)->nr_frags = ++nfrags;
533
534 pfrag->offset = pfrag->offset + allocsize;
535
536 spin_unlock_bh(&x->lock);
537
538 nfrags++;
539
540 skb->len += tailen;
541 skb->data_len += tailen;
542 skb->truesize += tailen;
543 if (sk && sk_fullsock(sk))
544 refcount_add(tailen, &sk->sk_wmem_alloc);
545
546 goto out;
547 }
548 }
549
550 cow:
551 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
552
553 nfrags = skb_cow_data(skb, tailen, &trailer);
554 if (nfrags < 0)
555 goto out;
556 tail = skb_tail_pointer(trailer);
557 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
558
559 skip_cow:
560 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
561 pskb_put(skb, trailer, tailen);
562
563 out:
564 return nfrags;
565 }
566 EXPORT_SYMBOL_GPL(esp6_output_head);
567
esp6_output_tail(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)568 int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
569 {
570 u8 *iv;
571 int alen;
572 void *tmp;
573 int ivlen;
574 int assoclen;
575 int extralen;
576 struct page *page;
577 struct ip_esp_hdr *esph;
578 struct aead_request *req;
579 struct crypto_aead *aead;
580 struct scatterlist *sg, *dsg;
581 struct esp_output_extra *extra;
582 int err = -ENOMEM;
583
584 assoclen = sizeof(struct ip_esp_hdr);
585 extralen = 0;
586
587 if (x->props.flags & XFRM_STATE_ESN) {
588 extralen += sizeof(*extra);
589 assoclen += sizeof(__be32);
590 }
591
592 aead = x->data;
593 alen = crypto_aead_authsize(aead);
594 ivlen = crypto_aead_ivsize(aead);
595
596 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
597 if (!tmp)
598 goto error;
599
600 extra = esp_tmp_extra(tmp);
601 iv = esp_tmp_iv(aead, tmp, extralen);
602 req = esp_tmp_req(aead, iv);
603 sg = esp_req_sg(aead, req);
604
605 if (esp->inplace)
606 dsg = sg;
607 else
608 dsg = &sg[esp->nfrags];
609
610 esph = esp_output_set_esn(skb, x, esp->esph, extra);
611 esp->esph = esph;
612
613 sg_init_table(sg, esp->nfrags);
614 err = skb_to_sgvec(skb, sg,
615 (unsigned char *)esph - skb->data,
616 assoclen + ivlen + esp->clen + alen);
617 if (unlikely(err < 0))
618 goto error_free;
619
620 if (!esp->inplace) {
621 int allocsize;
622 struct page_frag *pfrag = &x->xfrag;
623
624 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
625
626 spin_lock_bh(&x->lock);
627 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
628 spin_unlock_bh(&x->lock);
629 goto error_free;
630 }
631
632 skb_shinfo(skb)->nr_frags = 1;
633
634 page = pfrag->page;
635 get_page(page);
636 /* replace page frags in skb with new page */
637 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
638 pfrag->offset = pfrag->offset + allocsize;
639 spin_unlock_bh(&x->lock);
640
641 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
642 err = skb_to_sgvec(skb, dsg,
643 (unsigned char *)esph - skb->data,
644 assoclen + ivlen + esp->clen + alen);
645 if (unlikely(err < 0))
646 goto error_free;
647 }
648
649 if ((x->props.flags & XFRM_STATE_ESN))
650 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
651 else
652 aead_request_set_callback(req, 0, esp_output_done, skb);
653
654 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
655 aead_request_set_ad(req, assoclen);
656
657 memset(iv, 0, ivlen);
658 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
659 min(ivlen, 8));
660
661 ESP_SKB_CB(skb)->tmp = tmp;
662 err = crypto_aead_encrypt(req);
663
664 switch (err) {
665 case -EINPROGRESS:
666 goto error;
667
668 case -ENOSPC:
669 err = NET_XMIT_DROP;
670 break;
671
672 case 0:
673 if ((x->props.flags & XFRM_STATE_ESN))
674 esp_output_restore_header(skb);
675 esp_output_encap_csum(skb);
676 }
677
678 if (sg != dsg)
679 esp_ssg_unref(x, tmp, skb);
680
681 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
682 err = esp_output_tail_tcp(x, skb);
683
684 error_free:
685 kfree(tmp);
686 error:
687 return err;
688 }
689 EXPORT_SYMBOL_GPL(esp6_output_tail);
690
esp6_output(struct xfrm_state * x,struct sk_buff * skb)691 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
692 {
693 int alen;
694 int blksize;
695 struct ip_esp_hdr *esph;
696 struct crypto_aead *aead;
697 struct esp_info esp;
698
699 esp.inplace = true;
700
701 esp.proto = *skb_mac_header(skb);
702 *skb_mac_header(skb) = IPPROTO_ESP;
703
704 /* skb is pure payload to encrypt */
705
706 aead = x->data;
707 alen = crypto_aead_authsize(aead);
708
709 esp.tfclen = 0;
710 if (x->tfcpad) {
711 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
712 u32 padto;
713
714 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
715 if (skb->len < padto)
716 esp.tfclen = padto - skb->len;
717 }
718 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
719 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
720 esp.plen = esp.clen - skb->len - esp.tfclen;
721 esp.tailen = esp.tfclen + esp.plen + alen;
722
723 esp.esph = ip_esp_hdr(skb);
724
725 esp.nfrags = esp6_output_head(x, skb, &esp);
726 if (esp.nfrags < 0)
727 return esp.nfrags;
728
729 esph = esp.esph;
730 esph->spi = x->id.spi;
731
732 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
733 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
734 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
735
736 skb_push(skb, -skb_network_offset(skb));
737
738 return esp6_output_tail(x, skb, &esp);
739 }
740
esp_remove_trailer(struct sk_buff * skb)741 static inline int esp_remove_trailer(struct sk_buff *skb)
742 {
743 struct xfrm_state *x = xfrm_input_state(skb);
744 struct crypto_aead *aead = x->data;
745 int alen, hlen, elen;
746 int padlen, trimlen;
747 __wsum csumdiff;
748 u8 nexthdr[2];
749 int ret;
750
751 alen = crypto_aead_authsize(aead);
752 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
753 elen = skb->len - hlen;
754
755 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2);
756 BUG_ON(ret);
757
758 ret = -EINVAL;
759 padlen = nexthdr[0];
760 if (padlen + 2 + alen >= elen) {
761 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
762 padlen + 2, elen - alen);
763 goto out;
764 }
765
766 trimlen = alen + padlen + 2;
767 if (skb->ip_summed == CHECKSUM_COMPLETE) {
768 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
769 skb->csum = csum_block_sub(skb->csum, csumdiff,
770 skb->len - trimlen);
771 }
772 ret = pskb_trim(skb, skb->len - trimlen);
773 if (unlikely(ret))
774 return ret;
775
776 ret = nexthdr[1];
777
778 out:
779 return ret;
780 }
781
esp6_input_done2(struct sk_buff * skb,int err)782 int esp6_input_done2(struct sk_buff *skb, int err)
783 {
784 struct xfrm_state *x = xfrm_input_state(skb);
785 struct xfrm_offload *xo = xfrm_offload(skb);
786 struct crypto_aead *aead = x->data;
787 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
788 int hdr_len = skb_network_header_len(skb);
789
790 if (!xo || !(xo->flags & CRYPTO_DONE))
791 kfree(ESP_SKB_CB(skb)->tmp);
792
793 if (unlikely(err))
794 goto out;
795
796 err = esp_remove_trailer(skb);
797 if (unlikely(err < 0))
798 goto out;
799
800 if (x->encap) {
801 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
802 int offset = skb_network_offset(skb) + sizeof(*ip6h);
803 struct xfrm_encap_tmpl *encap = x->encap;
804 u8 nexthdr = ip6h->nexthdr;
805 __be16 frag_off, source;
806 struct udphdr *uh;
807 struct tcphdr *th;
808
809 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
810 if (offset == -1) {
811 err = -EINVAL;
812 goto out;
813 }
814
815 uh = (void *)(skb->data + offset);
816 th = (void *)(skb->data + offset);
817 hdr_len += offset;
818
819 switch (x->encap->encap_type) {
820 case TCP_ENCAP_ESPINTCP:
821 source = th->source;
822 break;
823 case UDP_ENCAP_ESPINUDP:
824 case UDP_ENCAP_ESPINUDP_NON_IKE:
825 source = uh->source;
826 break;
827 default:
828 WARN_ON_ONCE(1);
829 err = -EINVAL;
830 goto out;
831 }
832
833 /*
834 * 1) if the NAT-T peer's IP or port changed then
835 * advertise the change to the keying daemon.
836 * This is an inbound SA, so just compare
837 * SRC ports.
838 */
839 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) ||
840 source != encap->encap_sport) {
841 xfrm_address_t ipaddr;
842
843 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6));
844 km_new_mapping(x, &ipaddr, source);
845
846 /* XXX: perhaps add an extra
847 * policy check here, to see
848 * if we should allow or
849 * reject a packet from a
850 * different source
851 * address/port.
852 */
853 }
854
855 /*
856 * 2) ignore UDP/TCP checksums in case
857 * of NAT-T in Transport Mode, or
858 * perform other post-processing fixes
859 * as per draft-ietf-ipsec-udp-encaps-06,
860 * section 3.1.2
861 */
862 if (x->props.mode == XFRM_MODE_TRANSPORT)
863 skb->ip_summed = CHECKSUM_UNNECESSARY;
864 }
865
866 skb_postpull_rcsum(skb, skb_network_header(skb),
867 skb_network_header_len(skb));
868 skb_pull_rcsum(skb, hlen);
869 if (x->props.mode == XFRM_MODE_TUNNEL)
870 skb_reset_transport_header(skb);
871 else
872 skb_set_transport_header(skb, -hdr_len);
873
874 /* RFC4303: Drop dummy packets without any error */
875 if (err == IPPROTO_NONE)
876 err = -EINVAL;
877
878 out:
879 return err;
880 }
881 EXPORT_SYMBOL_GPL(esp6_input_done2);
882
esp_input_done(void * data,int err)883 static void esp_input_done(void *data, int err)
884 {
885 struct sk_buff *skb = data;
886
887 xfrm_input_resume(skb, esp6_input_done2(skb, err));
888 }
889
esp_input_restore_header(struct sk_buff * skb)890 static void esp_input_restore_header(struct sk_buff *skb)
891 {
892 esp_restore_header(skb, 0);
893 __skb_pull(skb, 4);
894 }
895
esp_input_set_header(struct sk_buff * skb,__be32 * seqhi)896 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
897 {
898 struct xfrm_state *x = xfrm_input_state(skb);
899
900 /* For ESN we move the header forward by 4 bytes to
901 * accommodate the high bits. We will move it back after
902 * decryption.
903 */
904 if ((x->props.flags & XFRM_STATE_ESN)) {
905 struct ip_esp_hdr *esph = skb_push(skb, 4);
906
907 *seqhi = esph->spi;
908 esph->spi = esph->seq_no;
909 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
910 }
911 }
912
esp_input_done_esn(void * data,int err)913 static void esp_input_done_esn(void *data, int err)
914 {
915 struct sk_buff *skb = data;
916
917 esp_input_restore_header(skb);
918 esp_input_done(data, err);
919 }
920
esp6_input(struct xfrm_state * x,struct sk_buff * skb)921 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
922 {
923 struct crypto_aead *aead = x->data;
924 struct aead_request *req;
925 struct sk_buff *trailer;
926 int ivlen = crypto_aead_ivsize(aead);
927 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
928 int nfrags;
929 int assoclen;
930 int seqhilen;
931 int ret = 0;
932 void *tmp;
933 __be32 *seqhi;
934 u8 *iv;
935 struct scatterlist *sg;
936
937 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) {
938 ret = -EINVAL;
939 goto out;
940 }
941
942 if (elen <= 0) {
943 ret = -EINVAL;
944 goto out;
945 }
946
947 assoclen = sizeof(struct ip_esp_hdr);
948 seqhilen = 0;
949
950 if (x->props.flags & XFRM_STATE_ESN) {
951 seqhilen += sizeof(__be32);
952 assoclen += seqhilen;
953 }
954
955 if (!skb_cloned(skb)) {
956 if (!skb_is_nonlinear(skb)) {
957 nfrags = 1;
958
959 goto skip_cow;
960 } else if (!skb_has_frag_list(skb)) {
961 nfrags = skb_shinfo(skb)->nr_frags;
962 nfrags++;
963
964 goto skip_cow;
965 }
966 }
967
968 nfrags = skb_cow_data(skb, 0, &trailer);
969 if (nfrags < 0) {
970 ret = -EINVAL;
971 goto out;
972 }
973
974 skip_cow:
975 ret = -ENOMEM;
976 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
977 if (!tmp)
978 goto out;
979
980 ESP_SKB_CB(skb)->tmp = tmp;
981 seqhi = esp_tmp_extra(tmp);
982 iv = esp_tmp_iv(aead, tmp, seqhilen);
983 req = esp_tmp_req(aead, iv);
984 sg = esp_req_sg(aead, req);
985
986 esp_input_set_header(skb, seqhi);
987
988 sg_init_table(sg, nfrags);
989 ret = skb_to_sgvec(skb, sg, 0, skb->len);
990 if (unlikely(ret < 0)) {
991 kfree(tmp);
992 goto out;
993 }
994
995 skb->ip_summed = CHECKSUM_NONE;
996
997 if ((x->props.flags & XFRM_STATE_ESN))
998 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
999 else
1000 aead_request_set_callback(req, 0, esp_input_done, skb);
1001
1002 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
1003 aead_request_set_ad(req, assoclen);
1004
1005 ret = crypto_aead_decrypt(req);
1006 if (ret == -EINPROGRESS)
1007 goto out;
1008
1009 if ((x->props.flags & XFRM_STATE_ESN))
1010 esp_input_restore_header(skb);
1011
1012 ret = esp6_input_done2(skb, ret);
1013
1014 out:
1015 return ret;
1016 }
1017
esp6_err(struct sk_buff * skb,struct inet6_skb_parm * opt,u8 type,u8 code,int offset,__be32 info)1018 static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
1019 u8 type, u8 code, int offset, __be32 info)
1020 {
1021 struct net *net = dev_net(skb->dev);
1022 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
1023 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
1024 struct xfrm_state *x;
1025
1026 if (type != ICMPV6_PKT_TOOBIG &&
1027 type != NDISC_REDIRECT)
1028 return 0;
1029
1030 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
1031 esph->spi, IPPROTO_ESP, AF_INET6);
1032 if (!x)
1033 return 0;
1034
1035 if (type == NDISC_REDIRECT)
1036 ip6_redirect(skb, net, skb->dev->ifindex, 0,
1037 sock_net_uid(net, NULL));
1038 else
1039 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
1040 xfrm_state_put(x);
1041
1042 return 0;
1043 }
1044
esp6_destroy(struct xfrm_state * x)1045 static void esp6_destroy(struct xfrm_state *x)
1046 {
1047 struct crypto_aead *aead = x->data;
1048
1049 if (!aead)
1050 return;
1051
1052 crypto_free_aead(aead);
1053 }
1054
esp_init_aead(struct xfrm_state * x,struct netlink_ext_ack * extack)1055 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
1056 {
1057 char aead_name[CRYPTO_MAX_ALG_NAME];
1058 struct crypto_aead *aead;
1059 int err;
1060
1061 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1062 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
1063 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1064 return -ENAMETOOLONG;
1065 }
1066
1067 aead = crypto_alloc_aead(aead_name, 0, 0);
1068 err = PTR_ERR(aead);
1069 if (IS_ERR(aead))
1070 goto error;
1071
1072 x->data = aead;
1073
1074 err = crypto_aead_setkey(aead, x->aead->alg_key,
1075 (x->aead->alg_key_len + 7) / 8);
1076 if (err)
1077 goto error;
1078
1079 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1080 if (err)
1081 goto error;
1082
1083 return 0;
1084
1085 error:
1086 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1087 return err;
1088 }
1089
esp_init_authenc(struct xfrm_state * x,struct netlink_ext_ack * extack)1090 static int esp_init_authenc(struct xfrm_state *x,
1091 struct netlink_ext_ack *extack)
1092 {
1093 struct crypto_aead *aead;
1094 struct crypto_authenc_key_param *param;
1095 struct rtattr *rta;
1096 char *key;
1097 char *p;
1098 char authenc_name[CRYPTO_MAX_ALG_NAME];
1099 unsigned int keylen;
1100 int err;
1101
1102 err = -ENAMETOOLONG;
1103
1104 if ((x->props.flags & XFRM_STATE_ESN)) {
1105 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1106 "%s%sauthencesn(%s,%s)%s",
1107 x->geniv ?: "", x->geniv ? "(" : "",
1108 x->aalg ? x->aalg->alg_name : "digest_null",
1109 x->ealg->alg_name,
1110 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1111 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1112 goto error;
1113 }
1114 } else {
1115 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1116 "%s%sauthenc(%s,%s)%s",
1117 x->geniv ?: "", x->geniv ? "(" : "",
1118 x->aalg ? x->aalg->alg_name : "digest_null",
1119 x->ealg->alg_name,
1120 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1121 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1122 goto error;
1123 }
1124 }
1125
1126 aead = crypto_alloc_aead(authenc_name, 0, 0);
1127 err = PTR_ERR(aead);
1128 if (IS_ERR(aead)) {
1129 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1130 goto error;
1131 }
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 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1162 goto free_key;
1163 }
1164
1165 err = crypto_aead_setauthsize(
1166 aead, x->aalg->alg_trunc_len / 8);
1167 if (err) {
1168 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1169 goto free_key;
1170 }
1171 }
1172
1173 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1174 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1175
1176 err = crypto_aead_setkey(aead, key, keylen);
1177
1178 free_key:
1179 kfree(key);
1180
1181 error:
1182 return err;
1183 }
1184
esp6_init_state(struct xfrm_state * x,struct netlink_ext_ack * extack)1185 static int esp6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
1186 {
1187 struct crypto_aead *aead;
1188 u32 align;
1189 int err;
1190
1191 x->data = NULL;
1192
1193 if (x->aead) {
1194 err = esp_init_aead(x, extack);
1195 } else if (x->ealg) {
1196 err = esp_init_authenc(x, extack);
1197 } else {
1198 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided");
1199 err = -EINVAL;
1200 }
1201
1202 if (err)
1203 goto error;
1204
1205 aead = x->data;
1206
1207 x->props.header_len = sizeof(struct ip_esp_hdr) +
1208 crypto_aead_ivsize(aead);
1209 switch (x->props.mode) {
1210 case XFRM_MODE_BEET:
1211 if (x->sel.family != AF_INET6)
1212 x->props.header_len += IPV4_BEET_PHMAXLEN +
1213 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
1214 break;
1215 default:
1216 case XFRM_MODE_TRANSPORT:
1217 break;
1218 case XFRM_MODE_TUNNEL:
1219 x->props.header_len += sizeof(struct ipv6hdr);
1220 break;
1221 }
1222
1223 if (x->encap) {
1224 struct xfrm_encap_tmpl *encap = x->encap;
1225
1226 switch (encap->encap_type) {
1227 default:
1228 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP");
1229 err = -EINVAL;
1230 goto error;
1231 case UDP_ENCAP_ESPINUDP:
1232 x->props.header_len += sizeof(struct udphdr);
1233 break;
1234 case UDP_ENCAP_ESPINUDP_NON_IKE:
1235 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
1236 break;
1237 #ifdef CONFIG_INET6_ESPINTCP
1238 case TCP_ENCAP_ESPINTCP:
1239 /* only the length field, TCP encap is done by
1240 * the socket
1241 */
1242 x->props.header_len += 2;
1243 break;
1244 #endif
1245 }
1246 }
1247
1248 align = ALIGN(crypto_aead_blocksize(aead), 4);
1249 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1250
1251 error:
1252 return err;
1253 }
1254
esp6_rcv_cb(struct sk_buff * skb,int err)1255 static int esp6_rcv_cb(struct sk_buff *skb, int err)
1256 {
1257 return 0;
1258 }
1259
1260 static const struct xfrm_type esp6_type = {
1261 .owner = THIS_MODULE,
1262 .proto = IPPROTO_ESP,
1263 .flags = XFRM_TYPE_REPLAY_PROT,
1264 .init_state = esp6_init_state,
1265 .destructor = esp6_destroy,
1266 .input = esp6_input,
1267 .output = esp6_output,
1268 };
1269
1270 static struct xfrm6_protocol esp6_protocol = {
1271 .handler = xfrm6_rcv,
1272 .input_handler = xfrm_input,
1273 .cb_handler = esp6_rcv_cb,
1274 .err_handler = esp6_err,
1275 .priority = 0,
1276 };
1277
esp6_init(void)1278 static int __init esp6_init(void)
1279 {
1280 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
1281 pr_info("%s: can't add xfrm type\n", __func__);
1282 return -EAGAIN;
1283 }
1284 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) {
1285 pr_info("%s: can't add protocol\n", __func__);
1286 xfrm_unregister_type(&esp6_type, AF_INET6);
1287 return -EAGAIN;
1288 }
1289
1290 return 0;
1291 }
1292
esp6_fini(void)1293 static void __exit esp6_fini(void)
1294 {
1295 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0)
1296 pr_info("%s: can't remove protocol\n", __func__);
1297 xfrm_unregister_type(&esp6_type, AF_INET6);
1298 }
1299
1300 module_init(esp6_init);
1301 module_exit(esp6_fini);
1302
1303 MODULE_LICENSE("GPL");
1304 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
1305