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