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, net->ipv4.tcp_death_row.hashinfo, x->id.daddr.a4,
136 dport, 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 esp_output_tail_tcp(x, skb);
240 else
241 xfrm_output_resume(skb_to_full_sk(skb), skb, err);
242 }
243 }
244
245 /* Move ESP header back into place. */
esp_restore_header(struct sk_buff * skb,unsigned int offset)246 static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
247 {
248 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
249 void *tmp = ESP_SKB_CB(skb)->tmp;
250 __be32 *seqhi = esp_tmp_extra(tmp);
251
252 esph->seq_no = esph->spi;
253 esph->spi = *seqhi;
254 }
255
esp_output_restore_header(struct sk_buff * skb)256 static void esp_output_restore_header(struct sk_buff *skb)
257 {
258 void *tmp = ESP_SKB_CB(skb)->tmp;
259 struct esp_output_extra *extra = esp_tmp_extra(tmp);
260
261 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
262 sizeof(__be32));
263 }
264
esp_output_set_extra(struct sk_buff * skb,struct xfrm_state * x,struct ip_esp_hdr * esph,struct esp_output_extra * extra)265 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
266 struct xfrm_state *x,
267 struct ip_esp_hdr *esph,
268 struct esp_output_extra *extra)
269 {
270 /* For ESN we move the header forward by 4 bytes to
271 * accommodate the high bits. We will move it back after
272 * encryption.
273 */
274 if ((x->props.flags & XFRM_STATE_ESN)) {
275 __u32 seqhi;
276 struct xfrm_offload *xo = xfrm_offload(skb);
277
278 if (xo)
279 seqhi = xo->seq.hi;
280 else
281 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
282
283 extra->esphoff = (unsigned char *)esph -
284 skb_transport_header(skb);
285 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
286 extra->seqhi = esph->spi;
287 esph->seq_no = htonl(seqhi);
288 }
289
290 esph->spi = x->id.spi;
291
292 return esph;
293 }
294
esp_output_done_esn(void * data,int err)295 static void esp_output_done_esn(void *data, int err)
296 {
297 struct sk_buff *skb = data;
298
299 esp_output_restore_header(skb);
300 esp_output_done(data, err);
301 }
302
esp_output_udp_encap(struct sk_buff * skb,int encap_type,struct esp_info * esp,__be16 sport,__be16 dport)303 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb,
304 int encap_type,
305 struct esp_info *esp,
306 __be16 sport,
307 __be16 dport)
308 {
309 struct udphdr *uh;
310 unsigned int len;
311 struct xfrm_offload *xo = xfrm_offload(skb);
312
313 len = skb->len + esp->tailen - skb_transport_offset(skb);
314 if (len + sizeof(struct iphdr) > IP_MAX_MTU)
315 return ERR_PTR(-EMSGSIZE);
316
317 uh = (struct udphdr *)esp->esph;
318 uh->source = sport;
319 uh->dest = dport;
320 uh->len = htons(len);
321 uh->check = 0;
322
323 /* For IPv4 ESP with UDP encapsulation, if xo is not null, the skb is in the crypto offload
324 * data path, which means that esp_output_udp_encap is called outside of the XFRM stack.
325 * In this case, the mac header doesn't point to the IPv4 protocol field, so don't set it.
326 */
327 if (!xo || encap_type != UDP_ENCAP_ESPINUDP)
328 *skb_mac_header(skb) = IPPROTO_UDP;
329
330 return (struct ip_esp_hdr *)(uh + 1);
331 }
332
333 #ifdef CONFIG_INET_ESPINTCP
esp_output_tcp_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)334 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
335 struct sk_buff *skb,
336 struct esp_info *esp)
337 {
338 __be16 *lenp = (void *)esp->esph;
339 struct ip_esp_hdr *esph;
340 unsigned int len;
341 struct sock *sk;
342
343 len = skb->len + esp->tailen - skb_transport_offset(skb);
344 if (len > IP_MAX_MTU)
345 return ERR_PTR(-EMSGSIZE);
346
347 rcu_read_lock();
348 sk = esp_find_tcp_sk(x);
349 rcu_read_unlock();
350
351 if (IS_ERR(sk))
352 return ERR_CAST(sk);
353
354 sock_put(sk);
355
356 *lenp = htons(len);
357 esph = (struct ip_esp_hdr *)(lenp + 1);
358
359 return esph;
360 }
361 #else
esp_output_tcp_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)362 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
363 struct sk_buff *skb,
364 struct esp_info *esp)
365 {
366 return ERR_PTR(-EOPNOTSUPP);
367 }
368 #endif
369
esp_output_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)370 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb,
371 struct esp_info *esp)
372 {
373 struct xfrm_encap_tmpl *encap = x->encap;
374 struct ip_esp_hdr *esph;
375 __be16 sport, dport;
376 int encap_type;
377
378 spin_lock_bh(&x->lock);
379 sport = encap->encap_sport;
380 dport = encap->encap_dport;
381 encap_type = encap->encap_type;
382 spin_unlock_bh(&x->lock);
383
384 switch (encap_type) {
385 default:
386 case UDP_ENCAP_ESPINUDP:
387 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport);
388 break;
389 case TCP_ENCAP_ESPINTCP:
390 esph = esp_output_tcp_encap(x, skb, esp);
391 break;
392 }
393
394 if (IS_ERR(esph))
395 return PTR_ERR(esph);
396
397 esp->esph = esph;
398
399 return 0;
400 }
401
esp_output_head(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)402 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
403 {
404 u8 *tail;
405 int nfrags;
406 int esph_offset;
407 struct page *page;
408 struct sk_buff *trailer;
409 int tailen = esp->tailen;
410
411 /* this is non-NULL only with TCP/UDP Encapsulation */
412 if (x->encap) {
413 int err = esp_output_encap(x, skb, esp);
414
415 if (err < 0)
416 return err;
417 }
418
419 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
420 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
421 goto cow;
422
423 if (!skb_cloned(skb)) {
424 if (tailen <= skb_tailroom(skb)) {
425 nfrags = 1;
426 trailer = skb;
427 tail = skb_tail_pointer(trailer);
428
429 goto skip_cow;
430 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
431 && !skb_has_frag_list(skb)) {
432 int allocsize;
433 struct sock *sk = skb->sk;
434 struct page_frag *pfrag = &x->xfrag;
435
436 esp->inplace = false;
437
438 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
439
440 spin_lock_bh(&x->lock);
441
442 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
443 spin_unlock_bh(&x->lock);
444 goto cow;
445 }
446
447 page = pfrag->page;
448 get_page(page);
449
450 tail = page_address(page) + pfrag->offset;
451
452 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
453
454 nfrags = skb_shinfo(skb)->nr_frags;
455
456 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
457 tailen);
458 skb_shinfo(skb)->nr_frags = ++nfrags;
459
460 pfrag->offset = pfrag->offset + allocsize;
461
462 spin_unlock_bh(&x->lock);
463
464 nfrags++;
465
466 skb_len_add(skb, tailen);
467 if (sk && sk_fullsock(sk))
468 refcount_add(tailen, &sk->sk_wmem_alloc);
469
470 goto out;
471 }
472 }
473
474 cow:
475 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
476
477 nfrags = skb_cow_data(skb, tailen, &trailer);
478 if (nfrags < 0)
479 goto out;
480 tail = skb_tail_pointer(trailer);
481 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
482
483 skip_cow:
484 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
485 pskb_put(skb, trailer, tailen);
486
487 out:
488 return nfrags;
489 }
490 EXPORT_SYMBOL_GPL(esp_output_head);
491
esp_output_tail(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)492 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
493 {
494 u8 *iv;
495 int alen;
496 void *tmp;
497 int ivlen;
498 int assoclen;
499 int extralen;
500 struct page *page;
501 struct ip_esp_hdr *esph;
502 struct crypto_aead *aead;
503 struct aead_request *req;
504 struct scatterlist *sg, *dsg;
505 struct esp_output_extra *extra;
506 int err = -ENOMEM;
507
508 assoclen = sizeof(struct ip_esp_hdr);
509 extralen = 0;
510
511 if (x->props.flags & XFRM_STATE_ESN) {
512 extralen += sizeof(*extra);
513 assoclen += sizeof(__be32);
514 }
515
516 aead = x->data;
517 alen = crypto_aead_authsize(aead);
518 ivlen = crypto_aead_ivsize(aead);
519
520 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
521 if (!tmp)
522 goto error;
523
524 extra = esp_tmp_extra(tmp);
525 iv = esp_tmp_iv(aead, tmp, extralen);
526 req = esp_tmp_req(aead, iv);
527 sg = esp_req_sg(aead, req);
528
529 if (esp->inplace)
530 dsg = sg;
531 else
532 dsg = &sg[esp->nfrags];
533
534 esph = esp_output_set_extra(skb, x, esp->esph, extra);
535 esp->esph = esph;
536
537 sg_init_table(sg, esp->nfrags);
538 err = skb_to_sgvec(skb, sg,
539 (unsigned char *)esph - skb->data,
540 assoclen + ivlen + esp->clen + alen);
541 if (unlikely(err < 0))
542 goto error_free;
543
544 if (!esp->inplace) {
545 int allocsize;
546 struct page_frag *pfrag = &x->xfrag;
547
548 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
549
550 spin_lock_bh(&x->lock);
551 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
552 spin_unlock_bh(&x->lock);
553 goto error_free;
554 }
555
556 skb_shinfo(skb)->nr_frags = 1;
557
558 page = pfrag->page;
559 get_page(page);
560 /* replace page frags in skb with new page */
561 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
562 pfrag->offset = pfrag->offset + allocsize;
563 spin_unlock_bh(&x->lock);
564
565 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
566 err = skb_to_sgvec(skb, dsg,
567 (unsigned char *)esph - skb->data,
568 assoclen + ivlen + esp->clen + alen);
569 if (unlikely(err < 0))
570 goto error_free;
571 }
572
573 if ((x->props.flags & XFRM_STATE_ESN))
574 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
575 else
576 aead_request_set_callback(req, 0, esp_output_done, skb);
577
578 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
579 aead_request_set_ad(req, assoclen);
580
581 memset(iv, 0, ivlen);
582 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
583 min(ivlen, 8));
584
585 ESP_SKB_CB(skb)->tmp = tmp;
586 err = crypto_aead_encrypt(req);
587
588 switch (err) {
589 case -EINPROGRESS:
590 goto error;
591
592 case -ENOSPC:
593 err = NET_XMIT_DROP;
594 break;
595
596 case 0:
597 if ((x->props.flags & XFRM_STATE_ESN))
598 esp_output_restore_header(skb);
599 }
600
601 if (sg != dsg)
602 esp_ssg_unref(x, tmp, skb);
603
604 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
605 err = esp_output_tail_tcp(x, skb);
606
607 error_free:
608 kfree(tmp);
609 error:
610 return err;
611 }
612 EXPORT_SYMBOL_GPL(esp_output_tail);
613
esp_output(struct xfrm_state * x,struct sk_buff * skb)614 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
615 {
616 int alen;
617 int blksize;
618 struct ip_esp_hdr *esph;
619 struct crypto_aead *aead;
620 struct esp_info esp;
621
622 esp.inplace = true;
623
624 esp.proto = *skb_mac_header(skb);
625 *skb_mac_header(skb) = IPPROTO_ESP;
626
627 /* skb is pure payload to encrypt */
628
629 aead = x->data;
630 alen = crypto_aead_authsize(aead);
631
632 esp.tfclen = 0;
633 if (x->tfcpad) {
634 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
635 u32 padto;
636
637 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
638 if (skb->len < padto)
639 esp.tfclen = padto - skb->len;
640 }
641 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
642 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
643 esp.plen = esp.clen - skb->len - esp.tfclen;
644 esp.tailen = esp.tfclen + esp.plen + alen;
645
646 esp.esph = ip_esp_hdr(skb);
647
648 esp.nfrags = esp_output_head(x, skb, &esp);
649 if (esp.nfrags < 0)
650 return esp.nfrags;
651
652 esph = esp.esph;
653 esph->spi = x->id.spi;
654
655 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
656 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
657 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
658
659 skb_push(skb, -skb_network_offset(skb));
660
661 return esp_output_tail(x, skb, &esp);
662 }
663
esp_remove_trailer(struct sk_buff * skb)664 static inline int esp_remove_trailer(struct sk_buff *skb)
665 {
666 struct xfrm_state *x = xfrm_input_state(skb);
667 struct crypto_aead *aead = x->data;
668 int alen, hlen, elen;
669 int padlen, trimlen;
670 __wsum csumdiff;
671 u8 nexthdr[2];
672 int ret;
673
674 alen = crypto_aead_authsize(aead);
675 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
676 elen = skb->len - hlen;
677
678 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
679 BUG();
680
681 ret = -EINVAL;
682 padlen = nexthdr[0];
683 if (padlen + 2 + alen >= elen) {
684 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
685 padlen + 2, elen - alen);
686 goto out;
687 }
688
689 trimlen = alen + padlen + 2;
690 if (skb->ip_summed == CHECKSUM_COMPLETE) {
691 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
692 skb->csum = csum_block_sub(skb->csum, csumdiff,
693 skb->len - trimlen);
694 }
695 ret = pskb_trim(skb, skb->len - trimlen);
696 if (unlikely(ret))
697 return ret;
698
699 ret = nexthdr[1];
700
701 out:
702 return ret;
703 }
704
esp_input_done2(struct sk_buff * skb,int err)705 int esp_input_done2(struct sk_buff *skb, int err)
706 {
707 const struct iphdr *iph;
708 struct xfrm_state *x = xfrm_input_state(skb);
709 struct xfrm_offload *xo = xfrm_offload(skb);
710 struct crypto_aead *aead = x->data;
711 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
712 int ihl;
713
714 if (!xo || !(xo->flags & CRYPTO_DONE))
715 kfree(ESP_SKB_CB(skb)->tmp);
716
717 if (unlikely(err))
718 goto out;
719
720 err = esp_remove_trailer(skb);
721 if (unlikely(err < 0))
722 goto out;
723
724 iph = ip_hdr(skb);
725 ihl = iph->ihl * 4;
726
727 if (x->encap) {
728 struct xfrm_encap_tmpl *encap = x->encap;
729 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl);
730 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
731 __be16 source;
732
733 switch (x->encap->encap_type) {
734 case TCP_ENCAP_ESPINTCP:
735 source = th->source;
736 break;
737 case UDP_ENCAP_ESPINUDP:
738 source = uh->source;
739 break;
740 default:
741 WARN_ON_ONCE(1);
742 err = -EINVAL;
743 goto out;
744 }
745
746 /*
747 * 1) if the NAT-T peer's IP or port changed then
748 * advertise the change to the keying daemon.
749 * This is an inbound SA, so just compare
750 * SRC ports.
751 */
752 if (iph->saddr != x->props.saddr.a4 ||
753 source != encap->encap_sport) {
754 xfrm_address_t ipaddr;
755
756 ipaddr.a4 = iph->saddr;
757 km_new_mapping(x, &ipaddr, source);
758
759 /* XXX: perhaps add an extra
760 * policy check here, to see
761 * if we should allow or
762 * reject a packet from a
763 * different source
764 * address/port.
765 */
766 }
767
768 /*
769 * 2) ignore UDP/TCP checksums in case
770 * of NAT-T in Transport Mode, or
771 * perform other post-processing fixes
772 * as per draft-ietf-ipsec-udp-encaps-06,
773 * section 3.1.2
774 */
775 if (x->props.mode == XFRM_MODE_TRANSPORT)
776 skb->ip_summed = CHECKSUM_UNNECESSARY;
777 }
778
779 skb_pull_rcsum(skb, hlen);
780 if (x->props.mode == XFRM_MODE_TUNNEL ||
781 x->props.mode == XFRM_MODE_IPTFS)
782 skb_reset_transport_header(skb);
783 else
784 skb_set_transport_header(skb, -ihl);
785
786 /* RFC4303: Drop dummy packets without any error */
787 if (err == IPPROTO_NONE)
788 err = -EINVAL;
789
790 out:
791 return err;
792 }
793 EXPORT_SYMBOL_GPL(esp_input_done2);
794
esp_input_done(void * data,int err)795 static void esp_input_done(void *data, int err)
796 {
797 struct sk_buff *skb = data;
798
799 xfrm_input_resume(skb, esp_input_done2(skb, err));
800 }
801
esp_input_restore_header(struct sk_buff * skb)802 static void esp_input_restore_header(struct sk_buff *skb)
803 {
804 esp_restore_header(skb, 0);
805 __skb_pull(skb, 4);
806 }
807
esp_input_set_header(struct sk_buff * skb,__be32 * seqhi)808 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
809 {
810 struct xfrm_state *x = xfrm_input_state(skb);
811 struct ip_esp_hdr *esph;
812
813 /* For ESN we move the header forward by 4 bytes to
814 * accommodate the high bits. We will move it back after
815 * decryption.
816 */
817 if ((x->props.flags & XFRM_STATE_ESN)) {
818 esph = skb_push(skb, 4);
819 *seqhi = esph->spi;
820 esph->spi = esph->seq_no;
821 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
822 }
823 }
824
esp_input_done_esn(void * data,int err)825 static void esp_input_done_esn(void *data, int err)
826 {
827 struct sk_buff *skb = data;
828
829 esp_input_restore_header(skb);
830 esp_input_done(data, err);
831 }
832
833 /*
834 * Note: detecting truncated vs. non-truncated authentication data is very
835 * expensive, so we only support truncated data, which is the recommended
836 * and common case.
837 */
esp_input(struct xfrm_state * x,struct sk_buff * skb)838 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
839 {
840 struct crypto_aead *aead = x->data;
841 struct aead_request *req;
842 struct sk_buff *trailer;
843 int ivlen = crypto_aead_ivsize(aead);
844 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
845 int nfrags;
846 int assoclen;
847 int seqhilen;
848 __be32 *seqhi;
849 void *tmp;
850 u8 *iv;
851 struct scatterlist *sg;
852 int err = -EINVAL;
853
854 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
855 goto out;
856
857 if (elen <= 0)
858 goto out;
859
860 assoclen = sizeof(struct ip_esp_hdr);
861 seqhilen = 0;
862
863 if (x->props.flags & XFRM_STATE_ESN) {
864 seqhilen += sizeof(__be32);
865 assoclen += seqhilen;
866 }
867
868 if (!skb_cloned(skb)) {
869 if (!skb_is_nonlinear(skb)) {
870 nfrags = 1;
871
872 goto skip_cow;
873 } else if (!skb_has_frag_list(skb)) {
874 nfrags = skb_shinfo(skb)->nr_frags;
875 nfrags++;
876
877 goto skip_cow;
878 }
879 }
880
881 err = skb_cow_data(skb, 0, &trailer);
882 if (err < 0)
883 goto out;
884
885 nfrags = err;
886
887 skip_cow:
888 err = -ENOMEM;
889 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
890 if (!tmp)
891 goto out;
892
893 ESP_SKB_CB(skb)->tmp = tmp;
894 seqhi = esp_tmp_extra(tmp);
895 iv = esp_tmp_iv(aead, tmp, seqhilen);
896 req = esp_tmp_req(aead, iv);
897 sg = esp_req_sg(aead, req);
898
899 esp_input_set_header(skb, seqhi);
900
901 sg_init_table(sg, nfrags);
902 err = skb_to_sgvec(skb, sg, 0, skb->len);
903 if (unlikely(err < 0)) {
904 kfree(tmp);
905 goto out;
906 }
907
908 skb->ip_summed = CHECKSUM_NONE;
909
910 if ((x->props.flags & XFRM_STATE_ESN))
911 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
912 else
913 aead_request_set_callback(req, 0, esp_input_done, skb);
914
915 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
916 aead_request_set_ad(req, assoclen);
917
918 err = crypto_aead_decrypt(req);
919 if (err == -EINPROGRESS)
920 goto out;
921
922 if ((x->props.flags & XFRM_STATE_ESN))
923 esp_input_restore_header(skb);
924
925 err = esp_input_done2(skb, err);
926
927 out:
928 return err;
929 }
930
esp4_err(struct sk_buff * skb,u32 info)931 static int esp4_err(struct sk_buff *skb, u32 info)
932 {
933 struct net *net = dev_net(skb->dev);
934 const struct iphdr *iph = (const struct iphdr *)skb->data;
935 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
936 struct xfrm_state *x;
937
938 switch (icmp_hdr(skb)->type) {
939 case ICMP_DEST_UNREACH:
940 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
941 return 0;
942 break;
943 case ICMP_REDIRECT:
944 break;
945 default:
946 return 0;
947 }
948
949 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
950 esph->spi, IPPROTO_ESP, AF_INET);
951 if (!x)
952 return 0;
953
954 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
955 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP);
956 else
957 ipv4_redirect(skb, net, 0, IPPROTO_ESP);
958 xfrm_state_put(x);
959
960 return 0;
961 }
962
esp_destroy(struct xfrm_state * x)963 static void esp_destroy(struct xfrm_state *x)
964 {
965 struct crypto_aead *aead = x->data;
966
967 if (!aead)
968 return;
969
970 crypto_free_aead(aead);
971 }
972
esp_init_aead(struct xfrm_state * x,struct netlink_ext_ack * extack)973 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
974 {
975 char aead_name[CRYPTO_MAX_ALG_NAME];
976 struct crypto_aead *aead;
977 int err;
978
979 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
980 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
981 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
982 return -ENAMETOOLONG;
983 }
984
985 aead = crypto_alloc_aead(aead_name, 0, 0);
986 err = PTR_ERR(aead);
987 if (IS_ERR(aead))
988 goto error;
989
990 x->data = aead;
991
992 err = crypto_aead_setkey(aead, x->aead->alg_key,
993 (x->aead->alg_key_len + 7) / 8);
994 if (err)
995 goto error;
996
997 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
998 if (err)
999 goto error;
1000
1001 return 0;
1002
1003 error:
1004 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1005 return err;
1006 }
1007
esp_init_authenc(struct xfrm_state * x,struct netlink_ext_ack * extack)1008 static int esp_init_authenc(struct xfrm_state *x,
1009 struct netlink_ext_ack *extack)
1010 {
1011 struct crypto_aead *aead;
1012 struct crypto_authenc_key_param *param;
1013 struct rtattr *rta;
1014 char *key;
1015 char *p;
1016 char authenc_name[CRYPTO_MAX_ALG_NAME];
1017 unsigned int keylen;
1018 int err;
1019
1020 err = -ENAMETOOLONG;
1021
1022 if ((x->props.flags & XFRM_STATE_ESN)) {
1023 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1024 "%s%sauthencesn(%s,%s)%s",
1025 x->geniv ?: "", x->geniv ? "(" : "",
1026 x->aalg ? x->aalg->alg_name : "digest_null",
1027 x->ealg->alg_name,
1028 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1029 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1030 goto error;
1031 }
1032 } else {
1033 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1034 "%s%sauthenc(%s,%s)%s",
1035 x->geniv ?: "", x->geniv ? "(" : "",
1036 x->aalg ? x->aalg->alg_name : "digest_null",
1037 x->ealg->alg_name,
1038 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1039 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1040 goto error;
1041 }
1042 }
1043
1044 aead = crypto_alloc_aead(authenc_name, 0, 0);
1045 err = PTR_ERR(aead);
1046 if (IS_ERR(aead)) {
1047 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1048 goto error;
1049 }
1050
1051 x->data = aead;
1052
1053 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1054 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1055 err = -ENOMEM;
1056 key = kmalloc(keylen, GFP_KERNEL);
1057 if (!key)
1058 goto error;
1059
1060 p = key;
1061 rta = (void *)p;
1062 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1063 rta->rta_len = RTA_LENGTH(sizeof(*param));
1064 param = RTA_DATA(rta);
1065 p += RTA_SPACE(sizeof(*param));
1066
1067 if (x->aalg) {
1068 struct xfrm_algo_desc *aalg_desc;
1069
1070 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1071 p += (x->aalg->alg_key_len + 7) / 8;
1072
1073 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1074 BUG_ON(!aalg_desc);
1075
1076 err = -EINVAL;
1077 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1078 crypto_aead_authsize(aead)) {
1079 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1080 goto free_key;
1081 }
1082
1083 err = crypto_aead_setauthsize(
1084 aead, x->aalg->alg_trunc_len / 8);
1085 if (err) {
1086 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1087 goto free_key;
1088 }
1089 }
1090
1091 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1092 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1093
1094 err = crypto_aead_setkey(aead, key, keylen);
1095
1096 free_key:
1097 kfree_sensitive(key);
1098
1099 error:
1100 return err;
1101 }
1102
esp_init_state(struct xfrm_state * x,struct netlink_ext_ack * extack)1103 static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
1104 {
1105 struct crypto_aead *aead;
1106 u32 align;
1107 int err;
1108
1109 x->data = NULL;
1110
1111 if (x->aead) {
1112 err = esp_init_aead(x, extack);
1113 } else if (x->ealg) {
1114 err = esp_init_authenc(x, extack);
1115 } else {
1116 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided");
1117 err = -EINVAL;
1118 }
1119
1120 if (err)
1121 goto error;
1122
1123 aead = x->data;
1124
1125 x->props.header_len = sizeof(struct ip_esp_hdr) +
1126 crypto_aead_ivsize(aead);
1127 if (x->props.mode == XFRM_MODE_TUNNEL)
1128 x->props.header_len += sizeof(struct iphdr);
1129 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
1130 x->props.header_len += IPV4_BEET_PHMAXLEN;
1131 if (x->encap) {
1132 struct xfrm_encap_tmpl *encap = x->encap;
1133
1134 switch (encap->encap_type) {
1135 default:
1136 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP");
1137 err = -EINVAL;
1138 goto error;
1139 case UDP_ENCAP_ESPINUDP:
1140 x->props.header_len += sizeof(struct udphdr);
1141 break;
1142 #ifdef CONFIG_INET_ESPINTCP
1143 case TCP_ENCAP_ESPINTCP:
1144 /* only the length field, TCP encap is done by
1145 * the socket
1146 */
1147 x->props.header_len += 2;
1148 break;
1149 #endif
1150 }
1151 }
1152
1153 align = ALIGN(crypto_aead_blocksize(aead), 4);
1154 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1155
1156 error:
1157 return err;
1158 }
1159
esp4_rcv_cb(struct sk_buff * skb,int err)1160 static int esp4_rcv_cb(struct sk_buff *skb, int err)
1161 {
1162 return 0;
1163 }
1164
1165 static const struct xfrm_type esp_type =
1166 {
1167 .owner = THIS_MODULE,
1168 .proto = IPPROTO_ESP,
1169 .flags = XFRM_TYPE_REPLAY_PROT,
1170 .init_state = esp_init_state,
1171 .destructor = esp_destroy,
1172 .input = esp_input,
1173 .output = esp_output,
1174 };
1175
1176 static struct xfrm4_protocol esp4_protocol = {
1177 .handler = xfrm4_rcv,
1178 .input_handler = xfrm_input,
1179 .cb_handler = esp4_rcv_cb,
1180 .err_handler = esp4_err,
1181 .priority = 0,
1182 };
1183
esp4_init(void)1184 static int __init esp4_init(void)
1185 {
1186 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1187 pr_info("%s: can't add xfrm type\n", __func__);
1188 return -EAGAIN;
1189 }
1190 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1191 pr_info("%s: can't add protocol\n", __func__);
1192 xfrm_unregister_type(&esp_type, AF_INET);
1193 return -EAGAIN;
1194 }
1195 return 0;
1196 }
1197
esp4_fini(void)1198 static void __exit esp4_fini(void)
1199 {
1200 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1201 pr_info("%s: can't remove protocol\n", __func__);
1202 xfrm_unregister_type(&esp_type, AF_INET);
1203 }
1204
1205 module_init(esp4_init);
1206 module_exit(esp4_fini);
1207 MODULE_DESCRIPTION("IPv4 ESP transformation library");
1208 MODULE_LICENSE("GPL");
1209 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
1210