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 */
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
69 static inline void *esp_tmp_extra(void *tmp)
70 {
71 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
72 }
73
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
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
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
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(sg_page(sg), skb->pp_recycle);
119 }
120
121 #ifdef CONFIG_INET_ESPINTCP
122 struct esp_tcp_sk {
123 struct sock *sk;
124 struct rcu_head rcu;
125 };
126
127 static void esp_free_tcp_sk(struct rcu_head *head)
128 {
129 struct esp_tcp_sk *esk = container_of(head, struct esp_tcp_sk, rcu);
130
131 sock_put(esk->sk);
132 kfree(esk);
133 }
134
135 static struct sock *esp_find_tcp_sk(struct xfrm_state *x)
136 {
137 struct xfrm_encap_tmpl *encap = x->encap;
138 struct net *net = xs_net(x);
139 struct esp_tcp_sk *esk;
140 __be16 sport, dport;
141 struct sock *nsk;
142 struct sock *sk;
143
144 sk = rcu_dereference(x->encap_sk);
145 if (sk && sk->sk_state == TCP_ESTABLISHED)
146 return sk;
147
148 spin_lock_bh(&x->lock);
149 sport = encap->encap_sport;
150 dport = encap->encap_dport;
151 nsk = rcu_dereference_protected(x->encap_sk,
152 lockdep_is_held(&x->lock));
153 if (sk && sk == nsk) {
154 esk = kmalloc(sizeof(*esk), GFP_ATOMIC);
155 if (!esk) {
156 spin_unlock_bh(&x->lock);
157 return ERR_PTR(-ENOMEM);
158 }
159 RCU_INIT_POINTER(x->encap_sk, NULL);
160 esk->sk = sk;
161 call_rcu(&esk->rcu, esp_free_tcp_sk);
162 }
163 spin_unlock_bh(&x->lock);
164
165 sk = inet_lookup_established(net, net->ipv4.tcp_death_row.hashinfo, x->id.daddr.a4,
166 dport, x->props.saddr.a4, sport, 0);
167 if (!sk)
168 return ERR_PTR(-ENOENT);
169
170 if (!tcp_is_ulp_esp(sk)) {
171 sock_put(sk);
172 return ERR_PTR(-EINVAL);
173 }
174
175 spin_lock_bh(&x->lock);
176 nsk = rcu_dereference_protected(x->encap_sk,
177 lockdep_is_held(&x->lock));
178 if (encap->encap_sport != sport ||
179 encap->encap_dport != dport) {
180 sock_put(sk);
181 sk = nsk ?: ERR_PTR(-EREMCHG);
182 } else if (sk == nsk) {
183 sock_put(sk);
184 } else {
185 rcu_assign_pointer(x->encap_sk, sk);
186 }
187 spin_unlock_bh(&x->lock);
188
189 return sk;
190 }
191
192 static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
193 {
194 struct sock *sk;
195 int err;
196
197 rcu_read_lock();
198
199 sk = esp_find_tcp_sk(x);
200 err = PTR_ERR_OR_ZERO(sk);
201 if (err)
202 goto out;
203
204 bh_lock_sock(sk);
205 if (sock_owned_by_user(sk))
206 err = espintcp_queue_out(sk, skb);
207 else
208 err = espintcp_push_skb(sk, skb);
209 bh_unlock_sock(sk);
210
211 out:
212 rcu_read_unlock();
213 return err;
214 }
215
216 static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
217 struct sk_buff *skb)
218 {
219 struct dst_entry *dst = skb_dst(skb);
220 struct xfrm_state *x = dst->xfrm;
221
222 return esp_output_tcp_finish(x, skb);
223 }
224
225 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
226 {
227 int err;
228
229 local_bh_disable();
230 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
231 local_bh_enable();
232
233 /* EINPROGRESS just happens to do the right thing. It
234 * actually means that the skb has been consumed and
235 * isn't coming back.
236 */
237 return err ?: -EINPROGRESS;
238 }
239 #else
240 static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
241 {
242 WARN_ON(1);
243 return -EOPNOTSUPP;
244 }
245 #endif
246
247 static void esp_output_done(void *data, int err)
248 {
249 struct sk_buff *skb = data;
250 struct xfrm_offload *xo = xfrm_offload(skb);
251 void *tmp;
252 struct xfrm_state *x;
253
254 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
255 struct sec_path *sp = skb_sec_path(skb);
256
257 x = sp->xvec[sp->len - 1];
258 } else {
259 x = skb_dst(skb)->xfrm;
260 }
261
262 tmp = ESP_SKB_CB(skb)->tmp;
263 esp_ssg_unref(x, tmp, skb);
264 kfree(tmp);
265
266 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
267 if (err) {
268 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
269 kfree_skb(skb);
270 return;
271 }
272
273 skb_push(skb, skb->data - skb_mac_header(skb));
274 secpath_reset(skb);
275 xfrm_dev_resume(skb);
276 } else {
277 if (!err &&
278 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
279 esp_output_tail_tcp(x, skb);
280 else
281 xfrm_output_resume(skb->sk, skb, err);
282 }
283 }
284
285 /* Move ESP header back into place. */
286 static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
287 {
288 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
289 void *tmp = ESP_SKB_CB(skb)->tmp;
290 __be32 *seqhi = esp_tmp_extra(tmp);
291
292 esph->seq_no = esph->spi;
293 esph->spi = *seqhi;
294 }
295
296 static void esp_output_restore_header(struct sk_buff *skb)
297 {
298 void *tmp = ESP_SKB_CB(skb)->tmp;
299 struct esp_output_extra *extra = esp_tmp_extra(tmp);
300
301 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
302 sizeof(__be32));
303 }
304
305 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
306 struct xfrm_state *x,
307 struct ip_esp_hdr *esph,
308 struct esp_output_extra *extra)
309 {
310 /* For ESN we move the header forward by 4 bytes to
311 * accommodate the high bits. We will move it back after
312 * encryption.
313 */
314 if ((x->props.flags & XFRM_STATE_ESN)) {
315 __u32 seqhi;
316 struct xfrm_offload *xo = xfrm_offload(skb);
317
318 if (xo)
319 seqhi = xo->seq.hi;
320 else
321 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
322
323 extra->esphoff = (unsigned char *)esph -
324 skb_transport_header(skb);
325 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
326 extra->seqhi = esph->spi;
327 esph->seq_no = htonl(seqhi);
328 }
329
330 esph->spi = x->id.spi;
331
332 return esph;
333 }
334
335 static void esp_output_done_esn(void *data, int err)
336 {
337 struct sk_buff *skb = data;
338
339 esp_output_restore_header(skb);
340 esp_output_done(data, err);
341 }
342
343 static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb,
344 int encap_type,
345 struct esp_info *esp,
346 __be16 sport,
347 __be16 dport)
348 {
349 struct udphdr *uh;
350 unsigned int len;
351 struct xfrm_offload *xo = xfrm_offload(skb);
352
353 len = skb->len + esp->tailen - skb_transport_offset(skb);
354 if (len + sizeof(struct iphdr) > IP_MAX_MTU)
355 return ERR_PTR(-EMSGSIZE);
356
357 uh = (struct udphdr *)esp->esph;
358 uh->source = sport;
359 uh->dest = dport;
360 uh->len = htons(len);
361 uh->check = 0;
362
363 /* For IPv4 ESP with UDP encapsulation, if xo is not null, the skb is in the crypto offload
364 * data path, which means that esp_output_udp_encap is called outside of the XFRM stack.
365 * In this case, the mac header doesn't point to the IPv4 protocol field, so don't set it.
366 */
367 if (!xo || encap_type != UDP_ENCAP_ESPINUDP)
368 *skb_mac_header(skb) = IPPROTO_UDP;
369
370 return (struct ip_esp_hdr *)(uh + 1);
371 }
372
373 #ifdef CONFIG_INET_ESPINTCP
374 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
375 struct sk_buff *skb,
376 struct esp_info *esp)
377 {
378 __be16 *lenp = (void *)esp->esph;
379 struct ip_esp_hdr *esph;
380 unsigned int len;
381 struct sock *sk;
382
383 len = skb->len + esp->tailen - skb_transport_offset(skb);
384 if (len > IP_MAX_MTU)
385 return ERR_PTR(-EMSGSIZE);
386
387 rcu_read_lock();
388 sk = esp_find_tcp_sk(x);
389 rcu_read_unlock();
390
391 if (IS_ERR(sk))
392 return ERR_CAST(sk);
393
394 *lenp = htons(len);
395 esph = (struct ip_esp_hdr *)(lenp + 1);
396
397 return esph;
398 }
399 #else
400 static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
401 struct sk_buff *skb,
402 struct esp_info *esp)
403 {
404 return ERR_PTR(-EOPNOTSUPP);
405 }
406 #endif
407
408 static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb,
409 struct esp_info *esp)
410 {
411 struct xfrm_encap_tmpl *encap = x->encap;
412 struct ip_esp_hdr *esph;
413 __be16 sport, dport;
414 int encap_type;
415
416 spin_lock_bh(&x->lock);
417 sport = encap->encap_sport;
418 dport = encap->encap_dport;
419 encap_type = encap->encap_type;
420 spin_unlock_bh(&x->lock);
421
422 switch (encap_type) {
423 default:
424 case UDP_ENCAP_ESPINUDP:
425 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport);
426 break;
427 case TCP_ENCAP_ESPINTCP:
428 esph = esp_output_tcp_encap(x, skb, esp);
429 break;
430 }
431
432 if (IS_ERR(esph))
433 return PTR_ERR(esph);
434
435 esp->esph = esph;
436
437 return 0;
438 }
439
440 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
441 {
442 u8 *tail;
443 int nfrags;
444 int esph_offset;
445 struct page *page;
446 struct sk_buff *trailer;
447 int tailen = esp->tailen;
448
449 /* this is non-NULL only with TCP/UDP Encapsulation */
450 if (x->encap) {
451 int err = esp_output_encap(x, skb, esp);
452
453 if (err < 0)
454 return err;
455 }
456
457 if (ALIGN(tailen, L1_CACHE_BYTES) > PAGE_SIZE ||
458 ALIGN(skb->data_len, L1_CACHE_BYTES) > PAGE_SIZE)
459 goto cow;
460
461 if (!skb_cloned(skb)) {
462 if (tailen <= skb_tailroom(skb)) {
463 nfrags = 1;
464 trailer = skb;
465 tail = skb_tail_pointer(trailer);
466
467 goto skip_cow;
468 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
469 && !skb_has_frag_list(skb)) {
470 int allocsize;
471 struct sock *sk = skb->sk;
472 struct page_frag *pfrag = &x->xfrag;
473
474 esp->inplace = false;
475
476 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
477
478 spin_lock_bh(&x->lock);
479
480 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
481 spin_unlock_bh(&x->lock);
482 goto cow;
483 }
484
485 page = pfrag->page;
486 get_page(page);
487
488 tail = page_address(page) + pfrag->offset;
489
490 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
491
492 nfrags = skb_shinfo(skb)->nr_frags;
493
494 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
495 tailen);
496 skb_shinfo(skb)->nr_frags = ++nfrags;
497
498 pfrag->offset = pfrag->offset + allocsize;
499
500 spin_unlock_bh(&x->lock);
501
502 nfrags++;
503
504 skb_len_add(skb, tailen);
505 if (sk && sk_fullsock(sk))
506 refcount_add(tailen, &sk->sk_wmem_alloc);
507
508 goto out;
509 }
510 }
511
512 cow:
513 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
514
515 nfrags = skb_cow_data(skb, tailen, &trailer);
516 if (nfrags < 0)
517 goto out;
518 tail = skb_tail_pointer(trailer);
519 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
520
521 skip_cow:
522 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
523 pskb_put(skb, trailer, tailen);
524
525 out:
526 return nfrags;
527 }
528 EXPORT_SYMBOL_GPL(esp_output_head);
529
530 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
531 {
532 u8 *iv;
533 int alen;
534 void *tmp;
535 int ivlen;
536 int assoclen;
537 int extralen;
538 struct page *page;
539 struct ip_esp_hdr *esph;
540 struct crypto_aead *aead;
541 struct aead_request *req;
542 struct scatterlist *sg, *dsg;
543 struct esp_output_extra *extra;
544 int err = -ENOMEM;
545
546 assoclen = sizeof(struct ip_esp_hdr);
547 extralen = 0;
548
549 if (x->props.flags & XFRM_STATE_ESN) {
550 extralen += sizeof(*extra);
551 assoclen += sizeof(__be32);
552 }
553
554 aead = x->data;
555 alen = crypto_aead_authsize(aead);
556 ivlen = crypto_aead_ivsize(aead);
557
558 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
559 if (!tmp)
560 goto error;
561
562 extra = esp_tmp_extra(tmp);
563 iv = esp_tmp_iv(aead, tmp, extralen);
564 req = esp_tmp_req(aead, iv);
565 sg = esp_req_sg(aead, req);
566
567 if (esp->inplace)
568 dsg = sg;
569 else
570 dsg = &sg[esp->nfrags];
571
572 esph = esp_output_set_extra(skb, x, esp->esph, extra);
573 esp->esph = esph;
574
575 sg_init_table(sg, esp->nfrags);
576 err = skb_to_sgvec(skb, sg,
577 (unsigned char *)esph - skb->data,
578 assoclen + ivlen + esp->clen + alen);
579 if (unlikely(err < 0))
580 goto error_free;
581
582 if (!esp->inplace) {
583 int allocsize;
584 struct page_frag *pfrag = &x->xfrag;
585
586 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
587
588 spin_lock_bh(&x->lock);
589 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
590 spin_unlock_bh(&x->lock);
591 goto error_free;
592 }
593
594 skb_shinfo(skb)->nr_frags = 1;
595
596 page = pfrag->page;
597 get_page(page);
598 /* replace page frags in skb with new page */
599 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
600 pfrag->offset = pfrag->offset + allocsize;
601 spin_unlock_bh(&x->lock);
602
603 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
604 err = skb_to_sgvec(skb, dsg,
605 (unsigned char *)esph - skb->data,
606 assoclen + ivlen + esp->clen + alen);
607 if (unlikely(err < 0))
608 goto error_free;
609 }
610
611 if ((x->props.flags & XFRM_STATE_ESN))
612 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
613 else
614 aead_request_set_callback(req, 0, esp_output_done, skb);
615
616 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
617 aead_request_set_ad(req, assoclen);
618
619 memset(iv, 0, ivlen);
620 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
621 min(ivlen, 8));
622
623 ESP_SKB_CB(skb)->tmp = tmp;
624 err = crypto_aead_encrypt(req);
625
626 switch (err) {
627 case -EINPROGRESS:
628 goto error;
629
630 case -ENOSPC:
631 err = NET_XMIT_DROP;
632 break;
633
634 case 0:
635 if ((x->props.flags & XFRM_STATE_ESN))
636 esp_output_restore_header(skb);
637 }
638
639 if (sg != dsg)
640 esp_ssg_unref(x, tmp, skb);
641
642 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
643 err = esp_output_tail_tcp(x, skb);
644
645 error_free:
646 kfree(tmp);
647 error:
648 return err;
649 }
650 EXPORT_SYMBOL_GPL(esp_output_tail);
651
652 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
653 {
654 int alen;
655 int blksize;
656 struct ip_esp_hdr *esph;
657 struct crypto_aead *aead;
658 struct esp_info esp;
659
660 esp.inplace = true;
661
662 esp.proto = *skb_mac_header(skb);
663 *skb_mac_header(skb) = IPPROTO_ESP;
664
665 /* skb is pure payload to encrypt */
666
667 aead = x->data;
668 alen = crypto_aead_authsize(aead);
669
670 esp.tfclen = 0;
671 if (x->tfcpad) {
672 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
673 u32 padto;
674
675 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
676 if (skb->len < padto)
677 esp.tfclen = padto - skb->len;
678 }
679 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
680 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
681 esp.plen = esp.clen - skb->len - esp.tfclen;
682 esp.tailen = esp.tfclen + esp.plen + alen;
683
684 esp.esph = ip_esp_hdr(skb);
685
686 esp.nfrags = esp_output_head(x, skb, &esp);
687 if (esp.nfrags < 0)
688 return esp.nfrags;
689
690 esph = esp.esph;
691 esph->spi = x->id.spi;
692
693 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
694 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
695 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
696
697 skb_push(skb, -skb_network_offset(skb));
698
699 return esp_output_tail(x, skb, &esp);
700 }
701
702 static inline int esp_remove_trailer(struct sk_buff *skb)
703 {
704 struct xfrm_state *x = xfrm_input_state(skb);
705 struct crypto_aead *aead = x->data;
706 int alen, hlen, elen;
707 int padlen, trimlen;
708 __wsum csumdiff;
709 u8 nexthdr[2];
710 int ret;
711
712 alen = crypto_aead_authsize(aead);
713 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
714 elen = skb->len - hlen;
715
716 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
717 BUG();
718
719 ret = -EINVAL;
720 padlen = nexthdr[0];
721 if (padlen + 2 + alen >= elen) {
722 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
723 padlen + 2, elen - alen);
724 goto out;
725 }
726
727 trimlen = alen + padlen + 2;
728 if (skb->ip_summed == CHECKSUM_COMPLETE) {
729 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
730 skb->csum = csum_block_sub(skb->csum, csumdiff,
731 skb->len - trimlen);
732 }
733 ret = pskb_trim(skb, skb->len - trimlen);
734 if (unlikely(ret))
735 return ret;
736
737 ret = nexthdr[1];
738
739 out:
740 return ret;
741 }
742
743 int esp_input_done2(struct sk_buff *skb, int err)
744 {
745 const struct iphdr *iph;
746 struct xfrm_state *x = xfrm_input_state(skb);
747 struct xfrm_offload *xo = xfrm_offload(skb);
748 struct crypto_aead *aead = x->data;
749 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
750 int ihl;
751
752 if (!xo || !(xo->flags & CRYPTO_DONE))
753 kfree(ESP_SKB_CB(skb)->tmp);
754
755 if (unlikely(err))
756 goto out;
757
758 err = esp_remove_trailer(skb);
759 if (unlikely(err < 0))
760 goto out;
761
762 iph = ip_hdr(skb);
763 ihl = iph->ihl * 4;
764
765 if (x->encap) {
766 struct xfrm_encap_tmpl *encap = x->encap;
767 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl);
768 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
769 __be16 source;
770
771 switch (x->encap->encap_type) {
772 case TCP_ENCAP_ESPINTCP:
773 source = th->source;
774 break;
775 case UDP_ENCAP_ESPINUDP:
776 source = uh->source;
777 break;
778 default:
779 WARN_ON_ONCE(1);
780 err = -EINVAL;
781 goto out;
782 }
783
784 /*
785 * 1) if the NAT-T peer's IP or port changed then
786 * advertise the change to the keying daemon.
787 * This is an inbound SA, so just compare
788 * SRC ports.
789 */
790 if (iph->saddr != x->props.saddr.a4 ||
791 source != encap->encap_sport) {
792 xfrm_address_t ipaddr;
793
794 ipaddr.a4 = iph->saddr;
795 km_new_mapping(x, &ipaddr, source);
796
797 /* XXX: perhaps add an extra
798 * policy check here, to see
799 * if we should allow or
800 * reject a packet from a
801 * different source
802 * address/port.
803 */
804 }
805
806 /*
807 * 2) ignore UDP/TCP checksums in case
808 * of NAT-T in Transport Mode, or
809 * perform other post-processing fixes
810 * as per draft-ietf-ipsec-udp-encaps-06,
811 * section 3.1.2
812 */
813 if (x->props.mode == XFRM_MODE_TRANSPORT)
814 skb->ip_summed = CHECKSUM_UNNECESSARY;
815 }
816
817 skb_pull_rcsum(skb, hlen);
818 if (x->props.mode == XFRM_MODE_TUNNEL)
819 skb_reset_transport_header(skb);
820 else
821 skb_set_transport_header(skb, -ihl);
822
823 /* RFC4303: Drop dummy packets without any error */
824 if (err == IPPROTO_NONE)
825 err = -EINVAL;
826
827 out:
828 return err;
829 }
830 EXPORT_SYMBOL_GPL(esp_input_done2);
831
832 static void esp_input_done(void *data, int err)
833 {
834 struct sk_buff *skb = data;
835
836 xfrm_input_resume(skb, esp_input_done2(skb, err));
837 }
838
839 static void esp_input_restore_header(struct sk_buff *skb)
840 {
841 esp_restore_header(skb, 0);
842 __skb_pull(skb, 4);
843 }
844
845 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
846 {
847 struct xfrm_state *x = xfrm_input_state(skb);
848 struct ip_esp_hdr *esph;
849
850 /* For ESN we move the header forward by 4 bytes to
851 * accommodate the high bits. We will move it back after
852 * decryption.
853 */
854 if ((x->props.flags & XFRM_STATE_ESN)) {
855 esph = skb_push(skb, 4);
856 *seqhi = esph->spi;
857 esph->spi = esph->seq_no;
858 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
859 }
860 }
861
862 static void esp_input_done_esn(void *data, int err)
863 {
864 struct sk_buff *skb = data;
865
866 esp_input_restore_header(skb);
867 esp_input_done(data, err);
868 }
869
870 /*
871 * Note: detecting truncated vs. non-truncated authentication data is very
872 * expensive, so we only support truncated data, which is the recommended
873 * and common case.
874 */
875 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
876 {
877 struct crypto_aead *aead = x->data;
878 struct aead_request *req;
879 struct sk_buff *trailer;
880 int ivlen = crypto_aead_ivsize(aead);
881 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
882 int nfrags;
883 int assoclen;
884 int seqhilen;
885 __be32 *seqhi;
886 void *tmp;
887 u8 *iv;
888 struct scatterlist *sg;
889 int err = -EINVAL;
890
891 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
892 goto out;
893
894 if (elen <= 0)
895 goto out;
896
897 assoclen = sizeof(struct ip_esp_hdr);
898 seqhilen = 0;
899
900 if (x->props.flags & XFRM_STATE_ESN) {
901 seqhilen += sizeof(__be32);
902 assoclen += seqhilen;
903 }
904
905 if (!skb_cloned(skb)) {
906 if (!skb_is_nonlinear(skb)) {
907 nfrags = 1;
908
909 goto skip_cow;
910 } else if (!skb_has_frag_list(skb)) {
911 nfrags = skb_shinfo(skb)->nr_frags;
912 nfrags++;
913
914 goto skip_cow;
915 }
916 }
917
918 err = skb_cow_data(skb, 0, &trailer);
919 if (err < 0)
920 goto out;
921
922 nfrags = err;
923
924 skip_cow:
925 err = -ENOMEM;
926 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
927 if (!tmp)
928 goto out;
929
930 ESP_SKB_CB(skb)->tmp = tmp;
931 seqhi = esp_tmp_extra(tmp);
932 iv = esp_tmp_iv(aead, tmp, seqhilen);
933 req = esp_tmp_req(aead, iv);
934 sg = esp_req_sg(aead, req);
935
936 esp_input_set_header(skb, seqhi);
937
938 sg_init_table(sg, nfrags);
939 err = skb_to_sgvec(skb, sg, 0, skb->len);
940 if (unlikely(err < 0)) {
941 kfree(tmp);
942 goto out;
943 }
944
945 skb->ip_summed = CHECKSUM_NONE;
946
947 if ((x->props.flags & XFRM_STATE_ESN))
948 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
949 else
950 aead_request_set_callback(req, 0, esp_input_done, skb);
951
952 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
953 aead_request_set_ad(req, assoclen);
954
955 err = crypto_aead_decrypt(req);
956 if (err == -EINPROGRESS)
957 goto out;
958
959 if ((x->props.flags & XFRM_STATE_ESN))
960 esp_input_restore_header(skb);
961
962 err = esp_input_done2(skb, err);
963
964 out:
965 return err;
966 }
967
968 static int esp4_err(struct sk_buff *skb, u32 info)
969 {
970 struct net *net = dev_net(skb->dev);
971 const struct iphdr *iph = (const struct iphdr *)skb->data;
972 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
973 struct xfrm_state *x;
974
975 switch (icmp_hdr(skb)->type) {
976 case ICMP_DEST_UNREACH:
977 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
978 return 0;
979 break;
980 case ICMP_REDIRECT:
981 break;
982 default:
983 return 0;
984 }
985
986 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
987 esph->spi, IPPROTO_ESP, AF_INET);
988 if (!x)
989 return 0;
990
991 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
992 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP);
993 else
994 ipv4_redirect(skb, net, 0, IPPROTO_ESP);
995 xfrm_state_put(x);
996
997 return 0;
998 }
999
1000 static void esp_destroy(struct xfrm_state *x)
1001 {
1002 struct crypto_aead *aead = x->data;
1003
1004 if (!aead)
1005 return;
1006
1007 crypto_free_aead(aead);
1008 }
1009
1010 static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
1011 {
1012 char aead_name[CRYPTO_MAX_ALG_NAME];
1013 struct crypto_aead *aead;
1014 int err;
1015
1016 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1017 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
1018 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1019 return -ENAMETOOLONG;
1020 }
1021
1022 aead = crypto_alloc_aead(aead_name, 0, 0);
1023 err = PTR_ERR(aead);
1024 if (IS_ERR(aead))
1025 goto error;
1026
1027 x->data = aead;
1028
1029 err = crypto_aead_setkey(aead, x->aead->alg_key,
1030 (x->aead->alg_key_len + 7) / 8);
1031 if (err)
1032 goto error;
1033
1034 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1035 if (err)
1036 goto error;
1037
1038 return 0;
1039
1040 error:
1041 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1042 return err;
1043 }
1044
1045 static int esp_init_authenc(struct xfrm_state *x,
1046 struct netlink_ext_ack *extack)
1047 {
1048 struct crypto_aead *aead;
1049 struct crypto_authenc_key_param *param;
1050 struct rtattr *rta;
1051 char *key;
1052 char *p;
1053 char authenc_name[CRYPTO_MAX_ALG_NAME];
1054 unsigned int keylen;
1055 int err;
1056
1057 err = -ENAMETOOLONG;
1058
1059 if ((x->props.flags & XFRM_STATE_ESN)) {
1060 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1061 "%s%sauthencesn(%s,%s)%s",
1062 x->geniv ?: "", x->geniv ? "(" : "",
1063 x->aalg ? x->aalg->alg_name : "digest_null",
1064 x->ealg->alg_name,
1065 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1066 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1067 goto error;
1068 }
1069 } else {
1070 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1071 "%s%sauthenc(%s,%s)%s",
1072 x->geniv ?: "", x->geniv ? "(" : "",
1073 x->aalg ? x->aalg->alg_name : "digest_null",
1074 x->ealg->alg_name,
1075 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1076 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1077 goto error;
1078 }
1079 }
1080
1081 aead = crypto_alloc_aead(authenc_name, 0, 0);
1082 err = PTR_ERR(aead);
1083 if (IS_ERR(aead)) {
1084 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1085 goto error;
1086 }
1087
1088 x->data = aead;
1089
1090 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1091 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1092 err = -ENOMEM;
1093 key = kmalloc(keylen, GFP_KERNEL);
1094 if (!key)
1095 goto error;
1096
1097 p = key;
1098 rta = (void *)p;
1099 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1100 rta->rta_len = RTA_LENGTH(sizeof(*param));
1101 param = RTA_DATA(rta);
1102 p += RTA_SPACE(sizeof(*param));
1103
1104 if (x->aalg) {
1105 struct xfrm_algo_desc *aalg_desc;
1106
1107 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1108 p += (x->aalg->alg_key_len + 7) / 8;
1109
1110 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1111 BUG_ON(!aalg_desc);
1112
1113 err = -EINVAL;
1114 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1115 crypto_aead_authsize(aead)) {
1116 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1117 goto free_key;
1118 }
1119
1120 err = crypto_aead_setauthsize(
1121 aead, x->aalg->alg_trunc_len / 8);
1122 if (err) {
1123 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1124 goto free_key;
1125 }
1126 }
1127
1128 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1129 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1130
1131 err = crypto_aead_setkey(aead, key, keylen);
1132
1133 free_key:
1134 kfree_sensitive(key);
1135
1136 error:
1137 return err;
1138 }
1139
1140 static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
1141 {
1142 struct crypto_aead *aead;
1143 u32 align;
1144 int err;
1145
1146 x->data = NULL;
1147
1148 if (x->aead) {
1149 err = esp_init_aead(x, extack);
1150 } else if (x->ealg) {
1151 err = esp_init_authenc(x, extack);
1152 } else {
1153 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided");
1154 err = -EINVAL;
1155 }
1156
1157 if (err)
1158 goto error;
1159
1160 aead = x->data;
1161
1162 x->props.header_len = sizeof(struct ip_esp_hdr) +
1163 crypto_aead_ivsize(aead);
1164 if (x->props.mode == XFRM_MODE_TUNNEL)
1165 x->props.header_len += sizeof(struct iphdr);
1166 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
1167 x->props.header_len += IPV4_BEET_PHMAXLEN;
1168 if (x->encap) {
1169 struct xfrm_encap_tmpl *encap = x->encap;
1170
1171 switch (encap->encap_type) {
1172 default:
1173 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP");
1174 err = -EINVAL;
1175 goto error;
1176 case UDP_ENCAP_ESPINUDP:
1177 x->props.header_len += sizeof(struct udphdr);
1178 break;
1179 #ifdef CONFIG_INET_ESPINTCP
1180 case TCP_ENCAP_ESPINTCP:
1181 /* only the length field, TCP encap is done by
1182 * the socket
1183 */
1184 x->props.header_len += 2;
1185 break;
1186 #endif
1187 }
1188 }
1189
1190 align = ALIGN(crypto_aead_blocksize(aead), 4);
1191 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1192
1193 error:
1194 return err;
1195 }
1196
1197 static int esp4_rcv_cb(struct sk_buff *skb, int err)
1198 {
1199 return 0;
1200 }
1201
1202 static const struct xfrm_type esp_type =
1203 {
1204 .owner = THIS_MODULE,
1205 .proto = IPPROTO_ESP,
1206 .flags = XFRM_TYPE_REPLAY_PROT,
1207 .init_state = esp_init_state,
1208 .destructor = esp_destroy,
1209 .input = esp_input,
1210 .output = esp_output,
1211 };
1212
1213 static struct xfrm4_protocol esp4_protocol = {
1214 .handler = xfrm4_rcv,
1215 .input_handler = xfrm_input,
1216 .cb_handler = esp4_rcv_cb,
1217 .err_handler = esp4_err,
1218 .priority = 0,
1219 };
1220
1221 static int __init esp4_init(void)
1222 {
1223 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1224 pr_info("%s: can't add xfrm type\n", __func__);
1225 return -EAGAIN;
1226 }
1227 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1228 pr_info("%s: can't add protocol\n", __func__);
1229 xfrm_unregister_type(&esp_type, AF_INET);
1230 return -EAGAIN;
1231 }
1232 return 0;
1233 }
1234
1235 static void __exit esp4_fini(void)
1236 {
1237 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1238 pr_info("%s: can't remove protocol\n", __func__);
1239 xfrm_unregister_type(&esp_type, AF_INET);
1240 }
1241
1242 module_init(esp4_init);
1243 module_exit(esp4_fini);
1244 MODULE_DESCRIPTION("IPv4 ESP transformation library");
1245 MODULE_LICENSE("GPL");
1246 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
1247
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