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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
27struct esp_skb_cb {
28 struct xfrm_skb_cb xfrm;
29 void *tmp;
30};
31
32struct 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 */
47static 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
69static inline void *esp_tmp_extra(void *tmp)
70{
71 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
72}
73
74static 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
81static 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
91static 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
99static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb, bool already_unref)
100{
101 struct crypto_aead *aead = x->data;
102 int extralen = 0;
103 u8 *iv;
104 struct aead_request *req;
105 struct scatterlist *sg;
106
107 if (x->props.flags & XFRM_STATE_ESN)
108 extralen += sizeof(struct esp_output_extra);
109
110 iv = esp_tmp_iv(aead, tmp, extralen);
111 req = esp_tmp_req(aead, iv);
112
113 /* Unref skb_frag_pages in the src scatterlist if necessary.
114 * Skip the first sg which comes from skb->data.
115 */
116 if (already_unref || req->src != req->dst) {
117 struct scatterlist *src = already_unref ? esp_req_sg(aead, req) : req->src;
118
119 for (sg = sg_next(src); sg; sg = sg_next(sg))
120 skb_page_unref(page_to_netmem(sg_page(sg)),
121 skb->pp_recycle);
122 }
123}
124
125#ifdef CONFIG_INET_ESPINTCP
126static struct sock *esp_find_tcp_sk(struct xfrm_state *x)
127{
128 struct xfrm_encap_tmpl *encap = x->encap;
129 struct net *net = xs_net(x);
130 __be16 sport, dport;
131 struct sock *sk;
132
133 spin_lock_bh(&x->lock);
134 sport = encap->encap_sport;
135 dport = encap->encap_dport;
136 spin_unlock_bh(&x->lock);
137
138 sk = inet_lookup_established(net, x->id.daddr.a4, dport,
139 x->props.saddr.a4, sport, 0);
140 if (!sk)
141 return ERR_PTR(-ENOENT);
142
143 if (!tcp_is_ulp_esp(sk)) {
144 sock_put(sk);
145 return ERR_PTR(-EINVAL);
146 }
147
148 return sk;
149}
150
151static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
152{
153 struct sock *sk;
154 int err;
155
156 rcu_read_lock();
157
158 sk = esp_find_tcp_sk(x);
159 err = PTR_ERR_OR_ZERO(sk);
160 if (err) {
161 kfree_skb(skb);
162 goto out;
163 }
164
165 bh_lock_sock(sk);
166 if (sock_owned_by_user(sk))
167 err = espintcp_queue_out(sk, skb);
168 else
169 err = espintcp_push_skb(sk, skb);
170 bh_unlock_sock(sk);
171
172 sock_put(sk);
173
174out:
175 rcu_read_unlock();
176 return err;
177}
178
179static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
180 struct sk_buff *skb)
181{
182 struct dst_entry *dst = skb_dst(skb);
183 struct xfrm_state *x = dst->xfrm;
184
185 return esp_output_tcp_finish(x, skb);
186}
187
188static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
189{
190 int err;
191
192 local_bh_disable();
193 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
194 local_bh_enable();
195
196 /* EINPROGRESS just happens to do the right thing. It
197 * actually means that the skb has been consumed and
198 * isn't coming back.
199 */
200 return err ?: -EINPROGRESS;
201}
202#else
203static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
204{
205 WARN_ON(1);
206 return -EOPNOTSUPP;
207}
208#endif
209
210static void esp_output_done(void *data, int err)
211{
212 struct sk_buff *skb = data;
213 struct xfrm_offload *xo = xfrm_offload(skb);
214 void *tmp;
215 struct xfrm_state *x;
216
217 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
218 struct sec_path *sp = skb_sec_path(skb);
219
220 x = sp->xvec[sp->len - 1];
221 } else {
222 x = skb_dst(skb)->xfrm;
223 }
224
225 tmp = ESP_SKB_CB(skb)->tmp;
226 esp_ssg_unref(x, tmp, skb, false);
227 kfree(tmp);
228
229 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
230 if (err) {
231 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
232 kfree_skb(skb);
233 return;
234 }
235
236 skb_push(skb, skb->data - skb_mac_header(skb));
237 secpath_reset(skb);
238 xfrm_dev_resume(skb);
239 } else {
240 if (!err &&
241 x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP) {
242 err = esp_output_tail_tcp(x, skb);
243 if (err != -EINPROGRESS)
244 kfree_skb(skb);
245 } else {
246 xfrm_output_resume(skb_to_full_sk(skb), skb, err);
247 }
248 }
249}
250
251/* Move ESP header back into place. */
252static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
253{
254 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
255 void *tmp = ESP_SKB_CB(skb)->tmp;
256 __be32 *seqhi = esp_tmp_extra(tmp);
257
258 esph->seq_no = esph->spi;
259 esph->spi = *seqhi;
260}
261
262static void esp_output_restore_header(struct sk_buff *skb)
263{
264 void *tmp = ESP_SKB_CB(skb)->tmp;
265 struct esp_output_extra *extra = esp_tmp_extra(tmp);
266
267 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
268 sizeof(__be32));
269}
270
271static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
272 struct xfrm_state *x,
273 struct ip_esp_hdr *esph,
274 struct esp_output_extra *extra)
275{
276 /* For ESN we move the header forward by 4 bytes to
277 * accommodate the high bits. We will move it back after
278 * encryption.
279 */
280 if ((x->props.flags & XFRM_STATE_ESN)) {
281 __u32 seqhi;
282 struct xfrm_offload *xo = xfrm_offload(skb);
283
284 if (xo)
285 seqhi = xo->seq.hi;
286 else
287 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
288
289 extra->esphoff = (unsigned char *)esph -
290 skb_transport_header(skb);
291 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
292 extra->seqhi = esph->spi;
293 esph->seq_no = htonl(seqhi);
294 }
295
296 esph->spi = x->id.spi;
297
298 return esph;
299}
300
301static void esp_output_done_esn(void *data, int err)
302{
303 struct sk_buff *skb = data;
304
305 esp_output_restore_header(skb);
306 esp_output_done(data, err);
307}
308
309static struct ip_esp_hdr *esp_output_udp_encap(struct sk_buff *skb,
310 int encap_type,
311 struct esp_info *esp,
312 __be16 sport,
313 __be16 dport)
314{
315 struct udphdr *uh;
316 unsigned int len;
317 struct xfrm_offload *xo = xfrm_offload(skb);
318
319 len = skb->len + esp->tailen - skb_transport_offset(skb);
320 if (len + sizeof(struct iphdr) > IP_MAX_MTU)
321 return ERR_PTR(-EMSGSIZE);
322
323 uh = (struct udphdr *)esp->esph;
324 uh->source = sport;
325 uh->dest = dport;
326 udp_set_len_short(uh, len);
327 uh->check = 0;
328
329 /* For IPv4 ESP with UDP encapsulation, if xo is not null, the skb is in the crypto offload
330 * data path, which means that esp_output_udp_encap is called outside of the XFRM stack.
331 * In this case, the mac header doesn't point to the IPv4 protocol field, so don't set it.
332 */
333 if (!xo || encap_type != UDP_ENCAP_ESPINUDP)
334 *skb_mac_header(skb) = IPPROTO_UDP;
335
336 return (struct ip_esp_hdr *)(uh + 1);
337}
338
339#ifdef CONFIG_INET_ESPINTCP
340static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
341 struct sk_buff *skb,
342 struct esp_info *esp)
343{
344 __be16 *lenp = (void *)esp->esph;
345 struct ip_esp_hdr *esph;
346 unsigned int len;
347 struct sock *sk;
348
349 len = skb->len + esp->tailen - skb_transport_offset(skb);
350 if (len > IP_MAX_MTU)
351 return ERR_PTR(-EMSGSIZE);
352
353 rcu_read_lock();
354 sk = esp_find_tcp_sk(x);
355 rcu_read_unlock();
356
357 if (IS_ERR(sk))
358 return ERR_CAST(sk);
359
360 sock_put(sk);
361
362 *lenp = htons(len);
363 esph = (struct ip_esp_hdr *)(lenp + 1);
364
365 return esph;
366}
367#else
368static struct ip_esp_hdr *esp_output_tcp_encap(struct xfrm_state *x,
369 struct sk_buff *skb,
370 struct esp_info *esp)
371{
372 return ERR_PTR(-EOPNOTSUPP);
373}
374#endif
375
376static int esp_output_encap(struct xfrm_state *x, struct sk_buff *skb,
377 struct esp_info *esp)
378{
379 struct xfrm_encap_tmpl *encap = x->encap;
380 struct ip_esp_hdr *esph;
381 __be16 sport, dport;
382 int encap_type;
383
384 spin_lock_bh(&x->lock);
385 sport = encap->encap_sport;
386 dport = encap->encap_dport;
387 encap_type = encap->encap_type;
388 spin_unlock_bh(&x->lock);
389
390 switch (encap_type) {
391 default:
392 case UDP_ENCAP_ESPINUDP:
393 esph = esp_output_udp_encap(skb, encap_type, esp, sport, dport);
394 break;
395 case TCP_ENCAP_ESPINTCP:
396 esph = esp_output_tcp_encap(x, skb, esp);
397 break;
398 }
399
400 if (IS_ERR(esph))
401 return PTR_ERR(esph);
402
403 esp->esph = esph;
404
405 return 0;
406}
407
408int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
409{
410 u8 *tail;
411 int nfrags;
412 int esph_offset;
413 struct page *page;
414 struct sk_buff *trailer;
415 int tailen = esp->tailen;
416
417 /* this is non-NULL only with TCP/UDP Encapsulation */
418 if (x->encap) {
419 int err = esp_output_encap(x, skb, esp);
420
421 if (err < 0)
422 return err;
423 }
424
425 if (ALIGN(skb->data_len + tailen, L1_CACHE_BYTES) >
426 PAGE_SIZE)
427 goto cow;
428
429 if (!skb_cloned(skb)) {
430 if (tailen <= skb_tailroom(skb)) {
431 nfrags = 1;
432 trailer = skb;
433 tail = skb_tail_pointer(trailer);
434
435 goto skip_cow;
436 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
437 && !skb_has_frag_list(skb)) {
438 int allocsize;
439 struct sock *sk = skb->sk;
440 struct page_frag *pfrag = &x->xfrag;
441
442 esp->inplace = false;
443
444 /* Take real page refs and clear SKBFL_MANAGED_FRAG_REFS before
445 * we mutate the frag array, so the per-frag unref stays balanced
446 * for zerocopy managed frags (see __ip_append_data()).
447 */
448 skb_zcopy_downgrade_managed(skb);
449
450 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
451
452 spin_lock_bh(&x->lock);
453
454 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
455 spin_unlock_bh(&x->lock);
456 goto cow;
457 }
458
459 page = pfrag->page;
460 get_page(page);
461
462 tail = page_address(page) + pfrag->offset;
463
464 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
465
466 nfrags = skb_shinfo(skb)->nr_frags;
467
468 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
469 tailen);
470 skb_shinfo(skb)->nr_frags = ++nfrags;
471
472 pfrag->offset = pfrag->offset + allocsize;
473
474 spin_unlock_bh(&x->lock);
475
476 nfrags++;
477
478 skb_len_add(skb, tailen);
479 if (sk && sk_fullsock(sk))
480 refcount_add(tailen, &sk->sk_wmem_alloc);
481
482 goto out;
483 }
484 }
485
486cow:
487 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
488
489 nfrags = skb_cow_data(skb, tailen, &trailer);
490 if (nfrags < 0)
491 goto out;
492 tail = skb_tail_pointer(trailer);
493 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
494
495skip_cow:
496 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
497 pskb_put(skb, trailer, tailen);
498
499out:
500 return nfrags;
501}
502EXPORT_SYMBOL_GPL(esp_output_head);
503
504int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
505{
506 u8 *iv;
507 int alen;
508 void *tmp;
509 int ivlen;
510 int assoclen;
511 int extralen;
512 struct page *page;
513 struct ip_esp_hdr *esph;
514 struct crypto_aead *aead;
515 struct aead_request *req;
516 struct scatterlist *sg, *dsg;
517 struct esp_output_extra *extra;
518 int err = -ENOMEM;
519
520 assoclen = sizeof(struct ip_esp_hdr);
521 extralen = 0;
522
523 if (x->props.flags & XFRM_STATE_ESN) {
524 extralen += sizeof(*extra);
525 assoclen += sizeof(__be32);
526 }
527
528 aead = x->data;
529 alen = crypto_aead_authsize(aead);
530 ivlen = crypto_aead_ivsize(aead);
531
532 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
533 if (!tmp)
534 goto error;
535
536 extra = esp_tmp_extra(tmp);
537 iv = esp_tmp_iv(aead, tmp, extralen);
538 req = esp_tmp_req(aead, iv);
539 sg = esp_req_sg(aead, req);
540
541 if (esp->inplace)
542 dsg = sg;
543 else
544 dsg = &sg[esp->nfrags];
545
546 esph = esp_output_set_extra(skb, x, esp->esph, extra);
547 esp->esph = esph;
548
549 sg_init_table(sg, esp->nfrags);
550 err = skb_to_sgvec(skb, sg,
551 (unsigned char *)esph - skb->data,
552 assoclen + ivlen + esp->clen + alen);
553 if (unlikely(err < 0))
554 goto error_free;
555
556 if (!esp->inplace) {
557 int allocsize;
558 struct page_frag *pfrag = &x->xfrag;
559
560 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
561
562 spin_lock_bh(&x->lock);
563 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
564 spin_unlock_bh(&x->lock);
565 goto error_free;
566 }
567
568 skb_shinfo(skb)->nr_frags = 1;
569
570 page = pfrag->page;
571 get_page(page);
572 /* replace page frags in skb with new page */
573 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
574 pfrag->offset = pfrag->offset + allocsize;
575 spin_unlock_bh(&x->lock);
576
577 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
578 err = skb_to_sgvec(skb, dsg,
579 (unsigned char *)esph - skb->data,
580 assoclen + ivlen + esp->clen + alen);
581 if (unlikely(err < 0)) {
582 esp_ssg_unref(x, tmp, skb, true);
583 goto error_free;
584 }
585 }
586
587 if ((x->props.flags & XFRM_STATE_ESN))
588 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
589 else
590 aead_request_set_callback(req, 0, esp_output_done, skb);
591
592 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
593 aead_request_set_ad(req, assoclen);
594
595 memset(iv, 0, ivlen);
596 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
597 min(ivlen, 8));
598
599 ESP_SKB_CB(skb)->tmp = tmp;
600 err = crypto_aead_encrypt(req);
601
602 switch (err) {
603 case -EINPROGRESS:
604 goto error;
605
606 case -ENOSPC:
607 err = NET_XMIT_DROP;
608 break;
609
610 case 0:
611 if ((x->props.flags & XFRM_STATE_ESN))
612 esp_output_restore_header(skb);
613 }
614
615 if (sg != dsg)
616 esp_ssg_unref(x, tmp, skb, false);
617
618 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
619 err = esp_output_tail_tcp(x, skb);
620
621error_free:
622 kfree(tmp);
623error:
624 return err;
625}
626EXPORT_SYMBOL_GPL(esp_output_tail);
627
628static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
629{
630 int alen;
631 int blksize;
632 struct ip_esp_hdr *esph;
633 struct crypto_aead *aead;
634 struct esp_info esp;
635
636 esp.inplace = true;
637
638 esp.proto = *skb_mac_header(skb);
639 *skb_mac_header(skb) = IPPROTO_ESP;
640
641 /* skb is pure payload to encrypt */
642
643 aead = x->data;
644 alen = crypto_aead_authsize(aead);
645
646 esp.tfclen = 0;
647 if (x->tfcpad) {
648 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
649 u32 padto;
650
651 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
652 if (skb->len < padto)
653 esp.tfclen = padto - skb->len;
654 }
655 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
656 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
657 esp.plen = esp.clen - skb->len - esp.tfclen;
658 esp.tailen = esp.tfclen + esp.plen + alen;
659
660 esp.esph = ip_esp_hdr(skb);
661
662 esp.nfrags = esp_output_head(x, skb, &esp);
663 if (esp.nfrags < 0)
664 return esp.nfrags;
665
666 esph = esp.esph;
667 esph->spi = x->id.spi;
668
669 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
670 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
671 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
672
673 skb_push(skb, -skb_network_offset(skb));
674
675 return esp_output_tail(x, skb, &esp);
676}
677
678static inline int esp_remove_trailer(struct sk_buff *skb)
679{
680 struct xfrm_state *x = xfrm_input_state(skb);
681 struct crypto_aead *aead = x->data;
682 int alen, hlen, elen;
683 int padlen, trimlen;
684 __wsum csumdiff;
685 u8 nexthdr[2];
686 int ret;
687
688 alen = crypto_aead_authsize(aead);
689 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
690 elen = skb->len - hlen;
691
692 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
693 BUG();
694
695 ret = -EINVAL;
696 padlen = nexthdr[0];
697 if (padlen + 2 + alen >= elen) {
698 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
699 padlen + 2, elen - alen);
700 goto out;
701 }
702
703 trimlen = alen + padlen + 2;
704 if (skb->ip_summed == CHECKSUM_COMPLETE) {
705 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
706 skb->csum = csum_block_sub(skb->csum, csumdiff,
707 skb->len - trimlen);
708 }
709 ret = pskb_trim(skb, skb->len - trimlen);
710 if (unlikely(ret))
711 return ret;
712
713 ret = nexthdr[1];
714
715out:
716 return ret;
717}
718
719int esp_input_done2(struct sk_buff *skb, int err)
720{
721 const struct iphdr *iph;
722 struct xfrm_state *x = xfrm_input_state(skb);
723 struct xfrm_offload *xo = xfrm_offload(skb);
724 struct crypto_aead *aead = x->data;
725 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
726 int ihl;
727
728 if (!xo || !(xo->flags & CRYPTO_DONE))
729 kfree(ESP_SKB_CB(skb)->tmp);
730
731 if (unlikely(err))
732 goto out;
733
734 err = esp_remove_trailer(skb);
735 if (unlikely(err < 0))
736 goto out;
737
738 iph = ip_hdr(skb);
739 ihl = iph->ihl * 4;
740
741 if (x->encap) {
742 struct xfrm_encap_tmpl *encap = x->encap;
743 struct tcphdr *th = (void *)(skb_network_header(skb) + ihl);
744 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
745 __be16 source;
746
747 switch (x->encap->encap_type) {
748 case TCP_ENCAP_ESPINTCP:
749 source = th->source;
750 break;
751 case UDP_ENCAP_ESPINUDP:
752 source = uh->source;
753 break;
754 default:
755 WARN_ON_ONCE(1);
756 err = -EINVAL;
757 goto out;
758 }
759
760 /*
761 * 1) if the NAT-T peer's IP or port changed then
762 * advertise the change to the keying daemon.
763 * This is an inbound SA, so just compare
764 * SRC ports.
765 */
766 if (iph->saddr != x->props.saddr.a4 ||
767 source != encap->encap_sport) {
768 xfrm_address_t ipaddr;
769
770 ipaddr.a4 = iph->saddr;
771 km_new_mapping(x, &ipaddr, source);
772
773 /* XXX: perhaps add an extra
774 * policy check here, to see
775 * if we should allow or
776 * reject a packet from a
777 * different source
778 * address/port.
779 */
780 }
781
782 /*
783 * 2) ignore UDP/TCP checksums in case
784 * of NAT-T in Transport Mode, or
785 * perform other post-processing fixes
786 * as per draft-ietf-ipsec-udp-encaps-06,
787 * section 3.1.2
788 */
789 if (x->props.mode == XFRM_MODE_TRANSPORT)
790 skb->ip_summed = CHECKSUM_UNNECESSARY;
791 }
792
793 skb_pull_rcsum(skb, hlen);
794 if (x->props.mode == XFRM_MODE_TUNNEL ||
795 x->props.mode == XFRM_MODE_IPTFS)
796 skb_reset_transport_header(skb);
797 else
798 skb_set_transport_header(skb, -ihl);
799
800 /* RFC4303: Drop dummy packets without any error */
801 if (err == IPPROTO_NONE)
802 err = -EINVAL;
803
804out:
805 return err;
806}
807EXPORT_SYMBOL_GPL(esp_input_done2);
808
809static void esp_input_done(void *data, int err)
810{
811 struct sk_buff *skb = data;
812
813 xfrm_input_resume(skb, esp_input_done2(skb, err));
814}
815
816static void esp_input_restore_header(struct sk_buff *skb)
817{
818 esp_restore_header(skb, 0);
819 __skb_pull(skb, 4);
820}
821
822static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
823{
824 struct xfrm_state *x = xfrm_input_state(skb);
825 struct ip_esp_hdr *esph;
826
827 /* For ESN we move the header forward by 4 bytes to
828 * accommodate the high bits. We will move it back after
829 * decryption.
830 */
831 if ((x->props.flags & XFRM_STATE_ESN)) {
832 esph = skb_push(skb, 4);
833 *seqhi = esph->spi;
834 esph->spi = esph->seq_no;
835 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
836 }
837}
838
839static void esp_input_done_esn(void *data, int err)
840{
841 struct sk_buff *skb = data;
842
843 esp_input_restore_header(skb);
844 esp_input_done(data, err);
845}
846
847/*
848 * Note: detecting truncated vs. non-truncated authentication data is very
849 * expensive, so we only support truncated data, which is the recommended
850 * and common case.
851 */
852static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
853{
854 struct crypto_aead *aead = x->data;
855 struct aead_request *req;
856 struct sk_buff *trailer;
857 int ivlen = crypto_aead_ivsize(aead);
858 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
859 int nfrags;
860 int assoclen;
861 int seqhilen;
862 __be32 *seqhi;
863 void *tmp;
864 u8 *iv;
865 struct scatterlist *sg;
866 int err = -EINVAL;
867
868 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen))
869 goto out;
870
871 if (elen <= 0)
872 goto out;
873
874 assoclen = sizeof(struct ip_esp_hdr);
875 seqhilen = 0;
876
877 if (x->props.flags & XFRM_STATE_ESN) {
878 seqhilen += sizeof(__be32);
879 assoclen += seqhilen;
880 }
881
882 if (!skb_cloned(skb)) {
883 if (!skb_is_nonlinear(skb)) {
884 nfrags = 1;
885
886 goto skip_cow;
887 } else if (!skb_has_frag_list(skb) &&
888 !skb_has_shared_frag(skb)) {
889 nfrags = skb_shinfo(skb)->nr_frags;
890 nfrags++;
891
892 goto skip_cow;
893 }
894 }
895
896 err = skb_cow_data(skb, 0, &trailer);
897 if (err < 0)
898 goto out;
899
900 nfrags = err;
901
902skip_cow:
903 err = -ENOMEM;
904 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
905 if (!tmp)
906 goto out;
907
908 ESP_SKB_CB(skb)->tmp = tmp;
909 seqhi = esp_tmp_extra(tmp);
910 iv = esp_tmp_iv(aead, tmp, seqhilen);
911 req = esp_tmp_req(aead, iv);
912 sg = esp_req_sg(aead, req);
913
914 esp_input_set_header(skb, seqhi);
915
916 sg_init_table(sg, nfrags);
917 err = skb_to_sgvec(skb, sg, 0, skb->len);
918 if (unlikely(err < 0)) {
919 kfree(tmp);
920 goto out;
921 }
922
923 skb->ip_summed = CHECKSUM_NONE;
924
925 if ((x->props.flags & XFRM_STATE_ESN))
926 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
927 else
928 aead_request_set_callback(req, 0, esp_input_done, skb);
929
930 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
931 aead_request_set_ad(req, assoclen);
932
933 err = crypto_aead_decrypt(req);
934 if (err == -EINPROGRESS)
935 goto out;
936
937 if ((x->props.flags & XFRM_STATE_ESN))
938 esp_input_restore_header(skb);
939
940 err = esp_input_done2(skb, err);
941
942out:
943 return err;
944}
945
946static int esp4_err(struct sk_buff *skb, u32 info)
947{
948 struct net *net = dev_net(skb->dev);
949 const struct iphdr *iph = (const struct iphdr *)skb->data;
950 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
951 struct xfrm_state *x;
952
953 switch (icmp_hdr(skb)->type) {
954 case ICMP_DEST_UNREACH:
955 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
956 return 0;
957 break;
958 case ICMP_REDIRECT:
959 break;
960 default:
961 return 0;
962 }
963
964 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
965 esph->spi, IPPROTO_ESP, AF_INET);
966 if (!x)
967 return 0;
968
969 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
970 ipv4_update_pmtu(skb, net, info, 0, IPPROTO_ESP);
971 else
972 ipv4_redirect(skb, net, 0, IPPROTO_ESP);
973 xfrm_state_put(x);
974
975 return 0;
976}
977
978static void esp_destroy(struct xfrm_state *x)
979{
980 struct crypto_aead *aead = x->data;
981
982 if (!aead)
983 return;
984
985 crypto_free_aead(aead);
986}
987
988static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
989{
990 char aead_name[CRYPTO_MAX_ALG_NAME];
991 struct crypto_aead *aead;
992 int err;
993
994 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
995 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
996 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
997 return -ENAMETOOLONG;
998 }
999
1000 aead = crypto_alloc_aead(aead_name, 0, 0);
1001 err = PTR_ERR(aead);
1002 if (IS_ERR(aead))
1003 goto error;
1004
1005 x->data = aead;
1006
1007 err = crypto_aead_setkey(aead, x->aead->alg_key,
1008 (x->aead->alg_key_len + 7) / 8);
1009 if (err)
1010 goto error;
1011
1012 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1013 if (err)
1014 goto error;
1015
1016 return 0;
1017
1018error:
1019 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1020 return err;
1021}
1022
1023static int esp_init_authenc(struct xfrm_state *x,
1024 struct netlink_ext_ack *extack)
1025{
1026 struct crypto_aead *aead;
1027 struct crypto_authenc_key_param *param;
1028 struct rtattr *rta;
1029 char *key;
1030 char *p;
1031 char authenc_name[CRYPTO_MAX_ALG_NAME];
1032 unsigned int keylen;
1033 int err;
1034
1035 err = -ENAMETOOLONG;
1036
1037 if ((x->props.flags & XFRM_STATE_ESN)) {
1038 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1039 "%s%sauthencesn(%s,%s)%s",
1040 x->geniv ?: "", x->geniv ? "(" : "",
1041 x->aalg ? x->aalg->alg_name : "digest_null",
1042 x->ealg->alg_name,
1043 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1044 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1045 goto error;
1046 }
1047 } else {
1048 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1049 "%s%sauthenc(%s,%s)%s",
1050 x->geniv ?: "", x->geniv ? "(" : "",
1051 x->aalg ? x->aalg->alg_name : "digest_null",
1052 x->ealg->alg_name,
1053 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1054 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1055 goto error;
1056 }
1057 }
1058
1059 aead = crypto_alloc_aead(authenc_name, 0, 0);
1060 err = PTR_ERR(aead);
1061 if (IS_ERR(aead)) {
1062 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1063 goto error;
1064 }
1065
1066 x->data = aead;
1067
1068 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1069 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1070 err = -ENOMEM;
1071 key = kmalloc(keylen, GFP_KERNEL);
1072 if (!key)
1073 goto error;
1074
1075 p = key;
1076 rta = (void *)p;
1077 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1078 rta->rta_len = RTA_LENGTH(sizeof(*param));
1079 param = RTA_DATA(rta);
1080 p += RTA_SPACE(sizeof(*param));
1081
1082 if (x->aalg) {
1083 struct xfrm_algo_desc *aalg_desc;
1084
1085 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1086 p += (x->aalg->alg_key_len + 7) / 8;
1087
1088 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1089 BUG_ON(!aalg_desc);
1090
1091 err = -EINVAL;
1092 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1093 crypto_aead_authsize(aead)) {
1094 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1095 goto free_key;
1096 }
1097
1098 err = crypto_aead_setauthsize(
1099 aead, x->aalg->alg_trunc_len / 8);
1100 if (err) {
1101 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1102 goto free_key;
1103 }
1104 }
1105
1106 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1107 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1108
1109 err = crypto_aead_setkey(aead, key, keylen);
1110
1111free_key:
1112 kfree_sensitive(key);
1113
1114error:
1115 return err;
1116}
1117
1118static int esp_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
1119{
1120 struct crypto_aead *aead;
1121 u32 align;
1122 int err;
1123
1124 x->data = NULL;
1125
1126 if (x->aead) {
1127 err = esp_init_aead(x, extack);
1128 } else if (x->ealg) {
1129 err = esp_init_authenc(x, extack);
1130 } else {
1131 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided");
1132 err = -EINVAL;
1133 }
1134
1135 if (err)
1136 goto error;
1137
1138 aead = x->data;
1139
1140 x->props.header_len = sizeof(struct ip_esp_hdr) +
1141 crypto_aead_ivsize(aead);
1142 if (x->props.mode == XFRM_MODE_TUNNEL)
1143 x->props.header_len += sizeof(struct iphdr);
1144 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
1145 x->props.header_len += IPV4_BEET_PHMAXLEN;
1146 if (x->encap) {
1147 struct xfrm_encap_tmpl *encap = x->encap;
1148
1149 switch (encap->encap_type) {
1150 default:
1151 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP");
1152 err = -EINVAL;
1153 goto error;
1154 case UDP_ENCAP_ESPINUDP:
1155 x->props.header_len += sizeof(struct udphdr);
1156 break;
1157#ifdef CONFIG_INET_ESPINTCP
1158 case TCP_ENCAP_ESPINTCP:
1159 /* only the length field, TCP encap is done by
1160 * the socket
1161 */
1162 x->props.header_len += 2;
1163 break;
1164#endif
1165 }
1166 }
1167
1168 align = ALIGN(crypto_aead_blocksize(aead), 4);
1169 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1170
1171error:
1172 return err;
1173}
1174
1175static int esp4_rcv_cb(struct sk_buff *skb, int err)
1176{
1177 return 0;
1178}
1179
1180static const struct xfrm_type esp_type =
1181{
1182 .owner = THIS_MODULE,
1183 .proto = IPPROTO_ESP,
1184 .flags = XFRM_TYPE_REPLAY_PROT,
1185 .init_state = esp_init_state,
1186 .destructor = esp_destroy,
1187 .input = esp_input,
1188 .output = esp_output,
1189};
1190
1191static struct xfrm4_protocol esp4_protocol = {
1192 .handler = xfrm4_rcv,
1193 .input_handler = xfrm_input,
1194 .cb_handler = esp4_rcv_cb,
1195 .err_handler = esp4_err,
1196 .priority = 0,
1197};
1198
1199static int __init esp4_init(void)
1200{
1201 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1202 pr_info("%s: can't add xfrm type\n", __func__);
1203 return -EAGAIN;
1204 }
1205 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1206 pr_info("%s: can't add protocol\n", __func__);
1207 xfrm_unregister_type(&esp_type, AF_INET);
1208 return -EAGAIN;
1209 }
1210 return 0;
1211}
1212
1213static void __exit esp4_fini(void)
1214{
1215 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1216 pr_info("%s: can't remove protocol\n", __func__);
1217 xfrm_unregister_type(&esp_type, AF_INET);
1218}
1219
1220module_init(esp4_init);
1221module_exit(esp4_fini);
1222MODULE_DESCRIPTION("IPv4 ESP transformation library");
1223MODULE_LICENSE("GPL");
1224MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);