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 */
esp_alloc_tmp(struct crypto_aead * aead,int nfrags,int extralen)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
esp_tmp_extra(void * tmp)68 static inline void *esp_tmp_extra(void *tmp)
69 {
70 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
71 }
72
esp_tmp_iv(struct crypto_aead * aead,void * tmp,int extralen)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
esp_tmp_req(struct crypto_aead * aead,u8 * iv)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
esp_req_sg(struct crypto_aead * aead,struct aead_request * req)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
esp_ssg_unref(struct xfrm_state * x,void * tmp,struct sk_buff * skb)98 static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb)
99 {
100 struct crypto_aead *aead = x->data;
101 int extralen = 0;
102 u8 *iv;
103 struct aead_request *req;
104 struct scatterlist *sg;
105
106 if (x->props.flags & XFRM_STATE_ESN)
107 extralen += sizeof(struct esp_output_extra);
108
109 iv = esp_tmp_iv(aead, tmp, extralen);
110 req = esp_tmp_req(aead, iv);
111
112 /* Unref skb_frag_pages in the src scatterlist if necessary.
113 * Skip the first sg which comes from skb->data.
114 */
115 if (req->src != req->dst)
116 for (sg = sg_next(req->src); sg; sg = sg_next(sg))
117 skb_page_unref(skb, sg_page(sg), false);
118 }
119
120 #ifdef CONFIG_INET_ESPINTCP
121 struct esp_tcp_sk {
122 struct sock *sk;
123 struct rcu_head rcu;
124 };
125
esp_free_tcp_sk(struct rcu_head * head)126 static void esp_free_tcp_sk(struct rcu_head *head)
127 {
128 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu);
129
130 sock_put(esk->sk);
131 kfree(esk);
132 }
133
esp_find_tcp_sk(struct xfrm_state * x)134 static struct sock *esp_find_tcp_sk(struct xfrm_state *x)
135 {
136 struct xfrm_encap_tmpl *encap = x->encap;
137 struct net *net = xs_net(x);
138 struct esp_tcp_sk *esk;
139 __be16 sport, dport;
140 struct sock *nsk;
141 struct sock *sk;
142
143 sk = rcu_dereference(x->encap_sk);
144 if (sk && sk->sk_state == TCP_ESTABLISHED)
145 return sk;
146
147 spin_lock_bh(&x->lock);
148 sport = encap->encap_sport;
149 dport = encap->encap_dport;
150 nsk = rcu_dereference_protected(x->encap_sk,
151 lockdep_is_held(&x->lock));
152 if (sk && sk == nsk) {
153 esk = kmalloc(sizeof(*esk), GFP_ATOMIC);
154 if (!esk) {
155 spin_unlock_bh(&x->lock);
156 return ERR_PTR(-ENOMEM);
157 }
158 RCU_INIT_POINTER(x->encap_sk, NULL);
159 esk->sk = sk;
160 call_rcu(&esk->rcu, esp_free_tcp_sk);
161 }
162 spin_unlock_bh(&x->lock);
163
164 sk = inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, x->id.daddr.a4,
165 dport, x->props.saddr.a4, sport, 0);
166 if (!sk)
167 return ERR_PTR(-ENOENT);
168
169 if (!tcp_is_ulp_esp(sk)) {
170 sock_put(sk);
171 return ERR_PTR(-EINVAL);
172 }
173
174 spin_lock_bh(&x->lock);
175 nsk = rcu_dereference_protected(x->encap_sk,
176 lockdep_is_held(&x->lock));
177 if (encap->encap_sport != sport ||
178 encap->encap_dport != dport) {
179 sock_put(sk);
180 sk = nsk ?: ERR_PTR(-EREMCHG);
181 } else if (sk == nsk) {
182 sock_put(sk);
183 } else {
184 rcu_assign_pointer(x->encap_sk, sk);
185 }
186 spin_unlock_bh(&x->lock);
187
188 return sk;
189 }
190
esp_output_tcp_finish(struct xfrm_state * x,struct sk_buff * skb)191 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
192 {
193 struct sock *sk;
194 int err;
195
196 rcu_read_lock();
197
198 sk = esp_find_tcp_sk(x);
199 err = PTR_ERR_OR_ZERO(sk);
200 if (err)
201 goto out;
202
203 bh_lock_sock(sk);
204 if (sock_owned_by_user(sk))
205 err = espintcp_queue_out(sk, skb);
206 else
207 err = espintcp_push_skb(sk, skb);
208 bh_unlock_sock(sk);
209
210 out:
211 rcu_read_unlock();
212 return err;
213 }
214
esp_output_tcp_encap_cb(struct net * net,struct sock * sk,struct sk_buff * skb)215 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
216 struct sk_buff *skb)
217 {
218 struct dst_entry *dst = skb_dst(skb);
219 struct xfrm_state *x = dst->xfrm;
220
221 return esp_output_tcp_finish(x, skb);
222 }
223
esp_output_tail_tcp(struct xfrm_state * x,struct sk_buff * skb)224 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
225 {
226 int err;
227
228 local_bh_disable();
229 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
230 local_bh_enable();
231
232 /* EINPROGRESS just happens to do the right thing. It
233 * actually means that the skb has been consumed and
234 * isn't coming back.
235 */
236 return err ?: -EINPROGRESS;
237 }
238 #else
esp_output_tail_tcp(struct xfrm_state * x,struct sk_buff * skb)239 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
240 {
241 WARN_ON(1);
242 return -EOPNOTSUPP;
243 }
244 #endif
245
esp_output_done(void * data,int err)246 static void esp_output_done(void *data, int err)
247 {
248 struct sk_buff *skb = data;
249 struct xfrm_offload *xo = xfrm_offload(skb);
250 void *tmp;
251 struct xfrm_state *x;
252
253 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
254 struct sec_path *sp = skb_sec_path(skb);
255
256 x = sp->xvec[sp->len - 1];
257 } else {
258 x = skb_dst(skb)->xfrm;
259 }
260
261 tmp = ESP_SKB_CB(skb)->tmp;
262 esp_ssg_unref(x, tmp, skb);
263 kfree(tmp);
264
265 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
266 if (err) {
267 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
268 kfree_skb(skb);
269 return;
270 }
271
272 skb_push(skb, skb->data - skb_mac_header(skb));
273 secpath_reset(skb);
274 xfrm_dev_resume(skb);
275 } else {
276 if (!err &&
277 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
278 esp_output_tail_tcp(x, skb);
279 else
280 xfrm_output_resume(skb->sk, skb, err);
281 }
282 }
283
284 /* Move ESP header back into place. */
esp_restore_header(struct sk_buff * skb,unsigned int offset)285 static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
286 {
287 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
288 void *tmp = ESP_SKB_CB(skb)->tmp;
289 __be32 *seqhi = esp_tmp_extra(tmp);
290
291 esph->seq_no = esph->spi;
292 esph->spi = *seqhi;
293 }
294
esp_output_restore_header(struct sk_buff * skb)295 static void esp_output_restore_header(struct sk_buff *skb)
296 {
297 void *tmp = ESP_SKB_CB(skb)->tmp;
298 struct esp_output_extra *extra = esp_tmp_extra(tmp);
299
300 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
301 sizeof(__be32));
302 }
303
esp_output_set_extra(struct sk_buff * skb,struct xfrm_state * x,struct ip_esp_hdr * esph,struct esp_output_extra * extra)304 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
305 struct xfrm_state *x,
306 struct ip_esp_hdr *esph,
307 struct esp_output_extra *extra)
308 {
309 /* For ESN we move the header forward by 4 bytes to
310 * accommodate the high bits. We will move it back after
311 * encryption.
312 */
313 if ((x->props.flags & XFRM_STATE_ESN)) {
314 __u32 seqhi;
315 struct xfrm_offload *xo = xfrm_offload(skb);
316
317 if (xo)
318 seqhi = xo->seq.hi;
319 else
320 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
321
322 extra->esphoff = (unsigned char *)esph -
323 skb_transport_header(skb);
324 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
325 extra->seqhi = esph->spi;
326 esph->seq_no = htonl(seqhi);
327 }
328
329 esph->spi = x->id.spi;
330
331 return esph;
332 }
333
esp_output_done_esn(void * data,int err)334 static void esp_output_done_esn(void *data, int err)
335 {
336 struct sk_buff *skb = data;
337
338 esp_output_restore_header(skb);
339 esp_output_done(data, err);
340 }
341
esp_output_udp_encap(struct sk_buff * skb,int encap_type,struct esp_info * esp,__be16 sport,__be16 dport)342 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb,
343 int encap_type,
344 struct esp_info *esp,
345 __be16 sport,
346 __be16 dport)
347 {
348 struct udphdr *uh;
349 __be32 *udpdata32;
350 unsigned int len;
351
352 len = skb->len + esp->tailen - skb_transport_offset(skb);
353 if (len + sizeof(struct iphdr) > IP_MAX_MTU)
354 return ERR_PTR(-EMSGSIZE);
355
356 uh = (struct udphdr *)esp->esph;
357 uh->source = sport;
358 uh->dest = dport;
359 uh->len = htons(len);
360 uh->check = 0;
361
362 *skb_mac_header(skb) = IPPROTO_UDP;
363
364 if (encap_type == UDP_ENCAP_ESPINUDP_NON_IKE) {
365 udpdata32 = (__be32 *)(uh + 1);
366 udpdata32[0] = udpdata32[1] = 0;
367 return (struct ip_esp_hdr *)(udpdata32 + 2);
368 }
369
370 return (struct ip_esp_hdr *)(uh + 1);
371 }
372
373 #ifdef CONFIG_INET_ESPINTCP
esp_output_tcp_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)374 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
375 struct sk_buff *skb,
376 struct esp_info *esp)
377 {
378 __be16 *lenp = (void *)esp->esph;
379 struct ip_esp_hdr *esph;
380 unsigned int len;
381 struct sock *sk;
382
383 len = skb->len + esp->tailen - skb_transport_offset(skb);
384 if (len > IP_MAX_MTU)
385 return ERR_PTR(-EMSGSIZE);
386
387 rcu_read_lock();
388 sk = esp_find_tcp_sk(x);
389 rcu_read_unlock();
390
391 if (IS_ERR(sk))
392 return ERR_CAST(sk);
393
394 *lenp = htons(len);
395 esph = (struct ip_esp_hdr *)(lenp + 1);
396
397 return esph;
398 }
399 #else
esp_output_tcp_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)400 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
401 struct sk_buff *skb,
402 struct esp_info *esp)
403 {
404 return ERR_PTR(-EOPNOTSUPP);
405 }
406 #endif
407
esp_output_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)408 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb,
409 struct esp_info *esp)
410 {
411 struct xfrm_encap_tmpl *encap = x->encap;
412 struct ip_esp_hdr *esph;
413 __be16 sport, dport;
414 int encap_type;
415
416 spin_lock_bh(&x->lock);
417 sport = encap->encap_sport;
418 dport = encap->encap_dport;
419 encap_type = encap->encap_type;
420 spin_unlock_bh(&x->lock);
421
422 switch (encap_type) {
423 default:
424 case UDP_ENCAP_ESPINUDP:
425 case UDP_ENCAP_ESPINUDP_NON_IKE:
426 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport);
427 break;
428 case TCP_ENCAP_ESPINTCP:
429 esph = esp_output_tcp_encap(x, skb, esp);
430 break;
431 }
432
433 if (IS_ERR(esph))
434 return PTR_ERR(esph);
435
436 esp->esph = esph;
437
438 return 0;
439 }
440
esp_output_head(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)441 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
442 {
443 u8 *tail;
444 int nfrags;
445 int esph_offset;
446 struct page *page;
447 struct sk_buff *trailer;
448 int tailen = esp->tailen;
449
450 /* this is non-NULL only with TCP/UDP Encapsulation */
451 if (x->encap) {
452 int err = esp_output_encap(x, skb, esp);
453
454 if (err < 0)
455 return err;
456 }
457
458 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
459 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
460 goto cow;
461
462 if (!skb_cloned(skb)) {
463 if (tailen <= skb_tailroom(skb)) {
464 nfrags = 1;
465 trailer = skb;
466 tail = skb_tail_pointer(trailer);
467
468 goto skip_cow;
469 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
470 && !skb_has_frag_list(skb)) {
471 int allocsize;
472 struct sock *sk = skb->sk;
473 struct page_frag *pfrag = &x->xfrag;
474
475 esp->inplace = false;
476
477 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
478
479 spin_lock_bh(&x->lock);
480
481 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
482 spin_unlock_bh(&x->lock);
483 goto cow;
484 }
485
486 page = pfrag->page;
487 get_page(page);
488
489 tail = page_address(page) + pfrag->offset;
490
491 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
492
493 nfrags = skb_shinfo(skb)->nr_frags;
494
495 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
496 tailen);
497 skb_shinfo(skb)->nr_frags = ++nfrags;
498
499 pfrag->offset = pfrag->offset + allocsize;
500
501 spin_unlock_bh(&x->lock);
502
503 nfrags++;
504
505 skb_len_add(skb, tailen);
506 if (sk && sk_fullsock(sk))
507 refcount_add(tailen, &sk->sk_wmem_alloc);
508
509 goto out;
510 }
511 }
512
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
esp_output_tail(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)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, skb);
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
esp_output(struct xfrm_state * x,struct sk_buff * skb)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
esp_remove_trailer(struct sk_buff * skb)703 static inline int esp_remove_trailer(struct sk_buff *skb)
704 {
705 struct xfrm_state *x = xfrm_input_state(skb);
706 struct crypto_aead *aead = x->data;
707 int alen, hlen, elen;
708 int padlen, trimlen;
709 __wsum csumdiff;
710 u8 nexthdr[2];
711 int ret;
712
713 alen = crypto_aead_authsize(aead);
714 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
715 elen = skb->len - hlen;
716
717 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
718 BUG();
719
720 ret = -EINVAL;
721 padlen = nexthdr[0];
722 if (padlen + 2 + alen >= elen) {
723 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
724 padlen + 2, elen - alen);
725 goto out;
726 }
727
728 trimlen = alen + padlen + 2;
729 if (skb->ip_summed == CHECKSUM_COMPLETE) {
730 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
731 skb->csum = csum_block_sub(skb->csum, csumdiff,
732 skb->len - trimlen);
733 }
734 ret = pskb_trim(skb, skb->len - trimlen);
735 if (unlikely(ret))
736 return ret;
737
738 ret = nexthdr[1];
739
740 out:
741 return ret;
742 }
743
esp_input_done2(struct sk_buff * skb,int err)744 int esp_input_done2(struct sk_buff *skb, int err)
745 {
746 const struct iphdr *iph;
747 struct xfrm_state *x = xfrm_input_state(skb);
748 struct xfrm_offload *xo = xfrm_offload(skb);
749 struct crypto_aead *aead = x->data;
750 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
751 int ihl;
752
753 if (!xo || !(xo->flags & CRYPTO_DONE))
754 kfree(ESP_SKB_CB(skb)->tmp);
755
756 if (unlikely(err))
757 goto out;
758
759 err = esp_remove_trailer(skb);
760 if (unlikely(err < 0))
761 goto out;
762
763 iph = ip_hdr(skb);
764 ihl = iph->ihl * 4;
765
766 if (x->encap) {
767 struct xfrm_encap_tmpl *encap = x->encap;
768 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl);
769 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
770 __be16 source;
771
772 switch (x->encap->encap_type) {
773 case TCP_ENCAP_ESPINTCP:
774 source = th->source;
775 break;
776 case UDP_ENCAP_ESPINUDP:
777 case UDP_ENCAP_ESPINUDP_NON_IKE:
778 source = uh->source;
779 break;
780 default:
781 WARN_ON_ONCE(1);
782 err = -EINVAL;
783 goto out;
784 }
785
786 /*
787 * 1) if the NAT-T peer's IP or port changed then
788 * advertise the change to the keying daemon.
789 * This is an inbound SA, so just compare
790 * SRC ports.
791 */
792 if (iph->saddr != x->props.saddr.a4 ||
793 source != encap->encap_sport) {
794 xfrm_address_t ipaddr;
795
796 ipaddr.a4 = iph->saddr;
797 km_new_mapping(x, &ipaddr, source);
798
799 /* XXX: perhaps add an extra
800 * policy check here, to see
801 * if we should allow or
802 * reject a packet from a
803 * different source
804 * address/port.
805 */
806 }
807
808 /*
809 * 2) ignore UDP/TCP checksums in case
810 * of NAT-T in Transport Mode, or
811 * perform other post-processing fixes
812 * as per draft-ietf-ipsec-udp-encaps-06,
813 * section 3.1.2
814 */
815 if (x->props.mode == XFRM_MODE_TRANSPORT)
816 skb->ip_summed = CHECKSUM_UNNECESSARY;
817 }
818
819 skb_pull_rcsum(skb, hlen);
820 if (x->props.mode == XFRM_MODE_TUNNEL)
821 skb_reset_transport_header(skb);
822 else
823 skb_set_transport_header(skb, -ihl);
824
825 /* RFC4303: Drop dummy packets without any error */
826 if (err == IPPROTO_NONE)
827 err = -EINVAL;
828
829 out:
830 return err;
831 }
832 EXPORT_SYMBOL_GPL(esp_input_done2);
833
esp_input_done(void * data,int err)834 static void esp_input_done(void *data, int err)
835 {
836 struct sk_buff *skb = data;
837
838 xfrm_input_resume(skb, esp_input_done2(skb, err));
839 }
840
esp_input_restore_header(struct sk_buff * skb)841 static void esp_input_restore_header(struct sk_buff *skb)
842 {
843 esp_restore_header(skb, 0);
844 __skb_pull(skb, 4);
845 }
846
esp_input_set_header(struct sk_buff * skb,__be32 * seqhi)847 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
848 {
849 struct xfrm_state *x = xfrm_input_state(skb);
850 struct ip_esp_hdr *esph;
851
852 /* For ESN we move the header forward by 4 bytes to
853 * accommodate the high bits. We will move it back after
854 * decryption.
855 */
856 if ((x->props.flags & XFRM_STATE_ESN)) {
857 esph = skb_push(skb, 4);
858 *seqhi = esph->spi;
859 esph->spi = esph->seq_no;
860 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
861 }
862 }
863
esp_input_done_esn(void * data,int err)864 static void esp_input_done_esn(void *data, int err)
865 {
866 struct sk_buff *skb = data;
867
868 esp_input_restore_header(skb);
869 esp_input_done(data, err);
870 }
871
872 /*
873 * Note: detecting truncated vs. non-truncated authentication data is very
874 * expensive, so we only support truncated data, which is the recommended
875 * and common case.
876 */
esp_input(struct xfrm_state * x,struct sk_buff * skb)877 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
878 {
879 struct crypto_aead *aead = x->data;
880 struct aead_request *req;
881 struct sk_buff *trailer;
882 int ivlen = crypto_aead_ivsize(aead);
883 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
884 int nfrags;
885 int assoclen;
886 int seqhilen;
887 __be32 *seqhi;
888 void *tmp;
889 u8 *iv;
890 struct scatterlist *sg;
891 int err = -EINVAL;
892
893 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
894 goto out;
895
896 if (elen <= 0)
897 goto out;
898
899 assoclen = sizeof(struct ip_esp_hdr);
900 seqhilen = 0;
901
902 if (x->props.flags & XFRM_STATE_ESN) {
903 seqhilen += sizeof(__be32);
904 assoclen += seqhilen;
905 }
906
907 if (!skb_cloned(skb)) {
908 if (!skb_is_nonlinear(skb)) {
909 nfrags = 1;
910
911 goto skip_cow;
912 } else if (!skb_has_frag_list(skb)) {
913 nfrags = skb_shinfo(skb)->nr_frags;
914 nfrags++;
915
916 goto skip_cow;
917 }
918 }
919
920 err = skb_cow_data(skb, 0, &trailer);
921 if (err < 0)
922 goto out;
923
924 nfrags = err;
925
926 skip_cow:
927 err = -ENOMEM;
928 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
929 if (!tmp)
930 goto out;
931
932 ESP_SKB_CB(skb)->tmp = tmp;
933 seqhi = esp_tmp_extra(tmp);
934 iv = esp_tmp_iv(aead, tmp, seqhilen);
935 req = esp_tmp_req(aead, iv);
936 sg = esp_req_sg(aead, req);
937
938 esp_input_set_header(skb, seqhi);
939
940 sg_init_table(sg, nfrags);
941 err = skb_to_sgvec(skb, sg, 0, skb->len);
942 if (unlikely(err < 0)) {
943 kfree(tmp);
944 goto out;
945 }
946
947 skb->ip_summed = CHECKSUM_NONE;
948
949 if ((x->props.flags & XFRM_STATE_ESN))
950 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
951 else
952 aead_request_set_callback(req, 0, esp_input_done, skb);
953
954 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
955 aead_request_set_ad(req, assoclen);
956
957 err = crypto_aead_decrypt(req);
958 if (err == -EINPROGRESS)
959 goto out;
960
961 if ((x->props.flags & XFRM_STATE_ESN))
962 esp_input_restore_header(skb);
963
964 err = esp_input_done2(skb, err);
965
966 out:
967 return err;
968 }
969
esp4_err(struct sk_buff * skb,u32 info)970 static int esp4_err(struct sk_buff *skb, u32 info)
971 {
972 struct net *net = dev_net(skb->dev);
973 const struct iphdr *iph = (const struct iphdr *)skb->data;
974 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
975 struct xfrm_state *x;
976
977 switch (icmp_hdr(skb)->type) {
978 case ICMP_DEST_UNREACH:
979 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
980 return 0;
981 break;
982 case ICMP_REDIRECT:
983 break;
984 default:
985 return 0;
986 }
987
988 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
989 esph->spi, IPPROTO_ESP, AF_INET);
990 if (!x)
991 return 0;
992
993 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
994 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP);
995 else
996 ipv4_redirect(skb, net, 0, IPPROTO_ESP);
997 xfrm_state_put(x);
998
999 return 0;
1000 }
1001
esp_destroy(struct xfrm_state * x)1002 static void esp_destroy(struct xfrm_state *x)
1003 {
1004 struct crypto_aead *aead = x->data;
1005
1006 if (!aead)
1007 return;
1008
1009 crypto_free_aead(aead);
1010 }
1011
esp_init_aead(struct xfrm_state * x,struct netlink_ext_ack * extack)1012 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
1013 {
1014 char aead_name[CRYPTO_MAX_ALG_NAME];
1015 struct crypto_aead *aead;
1016 int err;
1017
1018 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1019 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
1020 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1021 return -ENAMETOOLONG;
1022 }
1023
1024 aead = crypto_alloc_aead(aead_name, 0, 0);
1025 err = PTR_ERR(aead);
1026 if (IS_ERR(aead))
1027 goto error;
1028
1029 x->data = aead;
1030
1031 err = crypto_aead_setkey(aead, x->aead->alg_key,
1032 (x->aead->alg_key_len + 7) / 8);
1033 if (err)
1034 goto error;
1035
1036 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1037 if (err)
1038 goto error;
1039
1040 return 0;
1041
1042 error:
1043 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1044 return err;
1045 }
1046
esp_init_authenc(struct xfrm_state * x,struct netlink_ext_ack * extack)1047 static int esp_init_authenc(struct xfrm_state *x,
1048 struct netlink_ext_ack *extack)
1049 {
1050 struct crypto_aead *aead;
1051 struct crypto_authenc_key_param *param;
1052 struct rtattr *rta;
1053 char *key;
1054 char *p;
1055 char authenc_name[CRYPTO_MAX_ALG_NAME];
1056 unsigned int keylen;
1057 int err;
1058
1059 err = -ENAMETOOLONG;
1060
1061 if ((x->props.flags & XFRM_STATE_ESN)) {
1062 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1063 "%s%sauthencesn(%s,%s)%s",
1064 x->geniv ?: "", x->geniv ? "(" : "",
1065 x->aalg ? x->aalg->alg_name : "digest_null",
1066 x->ealg->alg_name,
1067 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1068 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1069 goto error;
1070 }
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 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1079 goto error;
1080 }
1081 }
1082
1083 aead = crypto_alloc_aead(authenc_name, 0, 0);
1084 err = PTR_ERR(aead);
1085 if (IS_ERR(aead)) {
1086 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1087 goto error;
1088 }
1089
1090 x->data = aead;
1091
1092 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1093 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1094 err = -ENOMEM;
1095 key = kmalloc(keylen, GFP_KERNEL);
1096 if (!key)
1097 goto error;
1098
1099 p = key;
1100 rta = (void *)p;
1101 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1102 rta->rta_len = RTA_LENGTH(sizeof(*param));
1103 param = RTA_DATA(rta);
1104 p += RTA_SPACE(sizeof(*param));
1105
1106 if (x->aalg) {
1107 struct xfrm_algo_desc *aalg_desc;
1108
1109 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1110 p += (x->aalg->alg_key_len + 7) / 8;
1111
1112 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1113 BUG_ON(!aalg_desc);
1114
1115 err = -EINVAL;
1116 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1117 crypto_aead_authsize(aead)) {
1118 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1119 goto free_key;
1120 }
1121
1122 err = crypto_aead_setauthsize(
1123 aead, x->aalg->alg_trunc_len / 8);
1124 if (err) {
1125 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1126 goto free_key;
1127 }
1128 }
1129
1130 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1131 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1132
1133 err = crypto_aead_setkey(aead, key, keylen);
1134
1135 free_key:
1136 kfree_sensitive(key);
1137
1138 error:
1139 return err;
1140 }
1141
esp_init_state(struct xfrm_state * x,struct netlink_ext_ack * extack)1142 static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
1143 {
1144 struct crypto_aead *aead;
1145 u32 align;
1146 int err;
1147
1148 x->data = NULL;
1149
1150 if (x->aead) {
1151 err = esp_init_aead(x, extack);
1152 } else if (x->ealg) {
1153 err = esp_init_authenc(x, extack);
1154 } else {
1155 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided");
1156 err = -EINVAL;
1157 }
1158
1159 if (err)
1160 goto error;
1161
1162 aead = x->data;
1163
1164 x->props.header_len = sizeof(struct ip_esp_hdr) +
1165 crypto_aead_ivsize(aead);
1166 if (x->props.mode == XFRM_MODE_TUNNEL)
1167 x->props.header_len += sizeof(struct iphdr);
1168 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
1169 x->props.header_len += IPV4_BEET_PHMAXLEN;
1170 if (x->encap) {
1171 struct xfrm_encap_tmpl *encap = x->encap;
1172
1173 switch (encap->encap_type) {
1174 default:
1175 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP");
1176 err = -EINVAL;
1177 goto error;
1178 case UDP_ENCAP_ESPINUDP:
1179 x->props.header_len += sizeof(struct udphdr);
1180 break;
1181 case UDP_ENCAP_ESPINUDP_NON_IKE:
1182 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
1183 break;
1184 #ifdef CONFIG_INET_ESPINTCP
1185 case TCP_ENCAP_ESPINTCP:
1186 /* only the length field, TCP encap is done by
1187 * the socket
1188 */
1189 x->props.header_len += 2;
1190 break;
1191 #endif
1192 }
1193 }
1194
1195 align = ALIGN(crypto_aead_blocksize(aead), 4);
1196 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1197
1198 error:
1199 return err;
1200 }
1201
esp4_rcv_cb(struct sk_buff * skb,int err)1202 static int esp4_rcv_cb(struct sk_buff *skb, int err)
1203 {
1204 return 0;
1205 }
1206
1207 static const struct xfrm_type esp_type =
1208 {
1209 .owner = THIS_MODULE,
1210 .proto = IPPROTO_ESP,
1211 .flags = XFRM_TYPE_REPLAY_PROT,
1212 .init_state = esp_init_state,
1213 .destructor = esp_destroy,
1214 .input = esp_input,
1215 .output = esp_output,
1216 };
1217
1218 static struct xfrm4_protocol esp4_protocol = {
1219 .handler = xfrm4_rcv,
1220 .input_handler = xfrm_input,
1221 .cb_handler = esp4_rcv_cb,
1222 .err_handler = esp4_err,
1223 .priority = 0,
1224 };
1225
esp4_init(void)1226 static int __init esp4_init(void)
1227 {
1228 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1229 pr_info("%s: can't add xfrm type\n", __func__);
1230 return -EAGAIN;
1231 }
1232 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1233 pr_info("%s: can't add protocol\n", __func__);
1234 xfrm_unregister_type(&esp_type, AF_INET);
1235 return -EAGAIN;
1236 }
1237 return 0;
1238 }
1239
esp4_fini(void)1240 static void __exit esp4_fini(void)
1241 {
1242 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1243 pr_info("%s: can't remove protocol\n", __func__);
1244 xfrm_unregister_type(&esp_type, AF_INET);
1245 }
1246
1247 module_init(esp4_init);
1248 module_exit(esp4_fini);
1249 MODULE_LICENSE("GPL");
1250 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
1251