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