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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Copyright (C)2002 USAGI/WIDE Project
4 *
5 * Authors
6 *
7 * Mitsuru KANDA @USAGI : IPv6 Support
8 * Kazunori MIYAZAWA @USAGI :
9 * Kunihiro Ishiguro <[email protected]>
10 *
11 * This file is derived from net/ipv4/esp.c
12 */
13
14#define pr_fmt(fmt) "IPv6: " fmt
15
16#include <crypto/aead.h>
17#include <crypto/authenc.h>
18#include <linux/err.h>
19#include <linux/module.h>
20#include <net/ip.h>
21#include <net/xfrm.h>
22#include <net/esp.h>
23#include <linux/scatterlist.h>
24#include <linux/kernel.h>
25#include <linux/pfkeyv2.h>
26#include <linux/random.h>
27#include <linux/slab.h>
28#include <linux/spinlock.h>
29#include <net/ip6_checksum.h>
30#include <net/ip6_route.h>
31#include <net/icmp.h>
32#include <net/ipv6.h>
33#include <net/protocol.h>
34#include <net/udp.h>
35#include <linux/icmpv6.h>
36#include <net/tcp.h>
37#include <net/espintcp.h>
38#include <net/inet6_hashtables.h>
39#include <linux/skbuff_ref.h>
40
41#include <linux/highmem.h>
42
43struct esp_skb_cb {
44 struct xfrm_skb_cb xfrm;
45 void *tmp;
46};
47
48struct esp_output_extra {
49 __be32 seqhi;
50 u32 esphoff;
51};
52
53#define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
54
55/*
56 * Allocate an AEAD request structure with extra space for SG and IV.
57 *
58 * For alignment considerations the upper 32 bits of the sequence number are
59 * placed at the front, if present. Followed by the IV, the request and finally
60 * the SG list.
61 *
62 * TODO: Use spare space in skb for this where possible.
63 */
64static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int seqihlen)
65{
66 unsigned int len;
67
68 len = seqihlen;
69
70 len += crypto_aead_ivsize(aead);
71
72 if (len) {
73 len += crypto_aead_alignmask(aead) &
74 ~(crypto_tfm_ctx_alignment() - 1);
75 len = ALIGN(len, crypto_tfm_ctx_alignment());
76 }
77
78 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
79 len = ALIGN(len, __alignof__(struct scatterlist));
80
81 len += sizeof(struct scatterlist) * nfrags;
82
83 return kmalloc(len, GFP_ATOMIC);
84}
85
86static inline void *esp_tmp_extra(void *tmp)
87{
88 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
89}
90
91static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int seqhilen)
92{
93 return crypto_aead_ivsize(aead) ?
94 PTR_ALIGN((u8 *)tmp + seqhilen,
95 crypto_aead_alignmask(aead) + 1) : tmp + seqhilen;
96}
97
98static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
99{
100 struct aead_request *req;
101
102 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
103 crypto_tfm_ctx_alignment());
104 aead_request_set_tfm(req, aead);
105 return req;
106}
107
108static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
109 struct aead_request *req)
110{
111 return (void *)ALIGN((unsigned long)(req + 1) +
112 crypto_aead_reqsize(aead),
113 __alignof__(struct scatterlist));
114}
115
116static void esp_ssg_unref(struct xfrm_state *x, void *tmp, struct sk_buff *skb, bool already_unref)
117{
118 struct crypto_aead *aead = x->data;
119 int extralen = 0;
120 u8 *iv;
121 struct aead_request *req;
122 struct scatterlist *sg;
123
124 if (x->props.flags & XFRM_STATE_ESN)
125 extralen += sizeof(struct esp_output_extra);
126
127 iv = esp_tmp_iv(aead, tmp, extralen);
128 req = esp_tmp_req(aead, iv);
129
130 /* Unref skb_frag_pages in the src scatterlist if necessary.
131 * Skip the first sg which comes from skb->data.
132 */
133 if (already_unref || req->src != req->dst) {
134 struct scatterlist *src = already_unref ? esp_req_sg(aead, req) : req->src;
135
136 for (sg = sg_next(src); sg; sg = sg_next(sg))
137 skb_page_unref(page_to_netmem(sg_page(sg)),
138 skb->pp_recycle);
139 }
140}
141
142#ifdef CONFIG_INET6_ESPINTCP
143static struct sock *esp6_find_tcp_sk(struct xfrm_state *x)
144{
145 struct xfrm_encap_tmpl *encap = x->encap;
146 struct net *net = xs_net(x);
147 __be16 sport, dport;
148 struct sock *sk;
149
150 spin_lock_bh(&x->lock);
151 sport = encap->encap_sport;
152 dport = encap->encap_dport;
153 spin_unlock_bh(&x->lock);
154
155 sk = __inet6_lookup_established(net, &x->id.daddr.in6, dport,
156 &x->props.saddr.in6, ntohs(sport), 0, 0);
157 if (!sk)
158 return ERR_PTR(-ENOENT);
159
160 if (!tcp_is_ulp_esp(sk)) {
161 sock_put(sk);
162 return ERR_PTR(-EINVAL);
163 }
164
165 return sk;
166}
167
168static int esp_output_tcp_finish(struct xfrm_state *x, struct sk_buff *skb)
169{
170 struct sock *sk;
171 int err;
172
173 rcu_read_lock();
174
175 sk = esp6_find_tcp_sk(x);
176 err = PTR_ERR_OR_ZERO(sk);
177 if (err) {
178 kfree_skb(skb);
179 goto out;
180 }
181
182 bh_lock_sock(sk);
183 if (sock_owned_by_user(sk))
184 err = espintcp_queue_out(sk, skb);
185 else
186 err = espintcp_push_skb(sk, skb);
187 bh_unlock_sock(sk);
188
189 sock_put(sk);
190
191out:
192 rcu_read_unlock();
193 return err;
194}
195
196static int esp_output_tcp_encap_cb(struct net *net, struct sock *sk,
197 struct sk_buff *skb)
198{
199 struct dst_entry *dst = skb_dst(skb);
200 struct xfrm_state *x = dst->xfrm;
201
202 return esp_output_tcp_finish(x, skb);
203}
204
205static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
206{
207 int err;
208
209 local_bh_disable();
210 err = xfrm_trans_queue_net(xs_net(x), skb, esp_output_tcp_encap_cb);
211 local_bh_enable();
212
213 /* EINPROGRESS just happens to do the right thing. It
214 * actually means that the skb has been consumed and
215 * isn't coming back.
216 */
217 return err ?: -EINPROGRESS;
218}
219#else
220static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
221{
222 WARN_ON(1);
223 return -EOPNOTSUPP;
224}
225#endif
226
227static void esp_output_encap_csum(struct sk_buff *skb)
228{
229 /* UDP encap with IPv6 requires a valid checksum */
230 if (*skb_mac_header(skb) == IPPROTO_UDP) {
231 struct udphdr *uh = udp_hdr(skb);
232 struct ipv6hdr *ip6h = ipv6_hdr(skb);
233 /* esp6_output_udp_encap limits len to U16_MAX. */
234 int len = udp_get_len_short(uh);
235 unsigned int offset = skb_transport_offset(skb);
236 __wsum csum = skb_checksum(skb, offset, skb->len - offset, 0);
237
238 uh->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
239 len, IPPROTO_UDP, csum);
240 if (uh->check == 0)
241 uh->check = CSUM_MANGLED_0;
242 }
243}
244
245static void esp_output_done(void *data, int err)
246{
247 struct sk_buff *skb = data;
248 struct xfrm_offload *xo = xfrm_offload(skb);
249 void *tmp;
250 struct xfrm_state *x;
251
252 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
253 struct sec_path *sp = skb_sec_path(skb);
254
255 x = sp->xvec[sp->len - 1];
256 } else {
257 x = skb_dst(skb)->xfrm;
258 }
259
260 tmp = ESP_SKB_CB(skb)->tmp;
261 esp_ssg_unref(x, tmp, skb, false);
262 kfree(tmp);
263
264 esp_output_encap_csum(skb);
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 err = esp_output_tail_tcp(x, skb);
280 if (err != -EINPROGRESS)
281 kfree_skb(skb);
282 } else {
283 xfrm_output_resume(skb_to_full_sk(skb), skb, err);
284 }
285 }
286}
287
288/* Move ESP header back into place. */
289static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
290{
291 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
292 void *tmp = ESP_SKB_CB(skb)->tmp;
293 __be32 *seqhi = esp_tmp_extra(tmp);
294
295 esph->seq_no = esph->spi;
296 esph->spi = *seqhi;
297}
298
299static void esp_output_restore_header(struct sk_buff *skb)
300{
301 void *tmp = ESP_SKB_CB(skb)->tmp;
302 struct esp_output_extra *extra = esp_tmp_extra(tmp);
303
304 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
305 sizeof(__be32));
306}
307
308static struct ip_esp_hdr *esp_output_set_esn(struct sk_buff *skb,
309 struct xfrm_state *x,
310 struct ip_esp_hdr *esph,
311 struct esp_output_extra *extra)
312{
313 /* For ESN we move the header forward by 4 bytes to
314 * accommodate the high bits. We will move it back after
315 * encryption.
316 */
317 if ((x->props.flags & XFRM_STATE_ESN)) {
318 __u32 seqhi;
319 struct xfrm_offload *xo = xfrm_offload(skb);
320
321 if (xo)
322 seqhi = xo->seq.hi;
323 else
324 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
325
326 extra->esphoff = (unsigned char *)esph -
327 skb_transport_header(skb);
328 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
329 extra->seqhi = esph->spi;
330 esph->seq_no = htonl(seqhi);
331 }
332
333 esph->spi = x->id.spi;
334
335 return esph;
336}
337
338static void esp_output_done_esn(void *data, int err)
339{
340 struct sk_buff *skb = data;
341
342 esp_output_restore_header(skb);
343 esp_output_done(data, err);
344}
345
346static struct ip_esp_hdr *esp6_output_udp_encap(struct sk_buff *skb,
347 int encap_type,
348 struct esp_info *esp,
349 __be16 sport,
350 __be16 dport)
351{
352 struct udphdr *uh;
353 unsigned int len;
354
355 len = skb->len + esp->tailen - skb_transport_offset(skb);
356 if (len > U16_MAX)
357 return ERR_PTR(-EMSGSIZE);
358
359 uh = (struct udphdr *)esp->esph;
360 uh->source = sport;
361 uh->dest = dport;
362 udp_set_len_short(uh, len);
363 uh->check = 0;
364
365 *skb_mac_header(skb) = IPPROTO_UDP;
366
367 return (struct ip_esp_hdr *)(uh + 1);
368}
369
370#ifdef CONFIG_INET6_ESPINTCP
371static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x,
372 struct sk_buff *skb,
373 struct esp_info *esp)
374{
375 __be16 *lenp = (void *)esp->esph;
376 struct ip_esp_hdr *esph;
377 unsigned int len;
378 struct sock *sk;
379
380 len = skb->len + esp->tailen - skb_transport_offset(skb);
381 if (len > IP_MAX_MTU)
382 return ERR_PTR(-EMSGSIZE);
383
384 rcu_read_lock();
385 sk = esp6_find_tcp_sk(x);
386 rcu_read_unlock();
387
388 if (IS_ERR(sk))
389 return ERR_CAST(sk);
390
391 sock_put(sk);
392
393 *lenp = htons(len);
394 esph = (struct ip_esp_hdr *)(lenp + 1);
395
396 return esph;
397}
398#else
399static struct ip_esp_hdr *esp6_output_tcp_encap(struct xfrm_state *x,
400 struct sk_buff *skb,
401 struct esp_info *esp)
402{
403 return ERR_PTR(-EOPNOTSUPP);
404}
405#endif
406
407static int esp6_output_encap(struct xfrm_state *x, struct sk_buff *skb,
408 struct esp_info *esp)
409{
410 struct xfrm_encap_tmpl *encap = x->encap;
411 struct ip_esp_hdr *esph;
412 __be16 sport, dport;
413 int encap_type;
414
415 spin_lock_bh(&x->lock);
416 sport = encap->encap_sport;
417 dport = encap->encap_dport;
418 encap_type = encap->encap_type;
419 spin_unlock_bh(&x->lock);
420
421 switch (encap_type) {
422 default:
423 case UDP_ENCAP_ESPINUDP:
424 esph = esp6_output_udp_encap(skb, encap_type, esp, sport, dport);
425 break;
426 case TCP_ENCAP_ESPINTCP:
427 esph = esp6_output_tcp_encap(x, skb, esp);
428 break;
429 }
430
431 if (IS_ERR(esph))
432 return PTR_ERR(esph);
433
434 esp->esph = esph;
435
436 return 0;
437}
438
439int esp6_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
440{
441 u8 *tail;
442 int nfrags;
443 int esph_offset;
444 struct page *page;
445 struct sk_buff *trailer;
446 int tailen = esp->tailen;
447
448 if (x->encap) {
449 int err = esp6_output_encap(x, skb, esp);
450
451 if (err < 0)
452 return err;
453 }
454
455 if (ALIGN(skb->data_len + tailen, L1_CACHE_BYTES) >
456 PAGE_SIZE)
457 goto cow;
458
459 if (!skb_cloned(skb)) {
460 if (tailen <= skb_tailroom(skb)) {
461 nfrags = 1;
462 trailer = skb;
463 tail = skb_tail_pointer(trailer);
464
465 goto skip_cow;
466 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
467 && !skb_has_frag_list(skb)) {
468 int allocsize;
469 struct sock *sk = skb->sk;
470 struct page_frag *pfrag = &x->xfrag;
471
472 esp->inplace = false;
473
474 /* Take real page refs and clear SKBFL_MANAGED_FRAG_REFS before
475 * we mutate the frag array, so the per-frag unref stays balanced
476 * for zerocopy managed frags (see __ip_append_data()).
477 */
478 skb_zcopy_downgrade_managed(skb);
479
480 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
481
482 spin_lock_bh(&x->lock);
483
484 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
485 spin_unlock_bh(&x->lock);
486 goto cow;
487 }
488
489 page = pfrag->page;
490 get_page(page);
491
492 tail = page_address(page) + pfrag->offset;
493
494 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
495
496 nfrags = skb_shinfo(skb)->nr_frags;
497
498 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
499 tailen);
500 skb_shinfo(skb)->nr_frags = ++nfrags;
501
502 pfrag->offset = pfrag->offset + allocsize;
503
504 spin_unlock_bh(&x->lock);
505
506 nfrags++;
507
508 skb->len += tailen;
509 skb->data_len += tailen;
510 skb->truesize += tailen;
511 if (sk && sk_fullsock(sk))
512 refcount_add(tailen, &sk->sk_wmem_alloc);
513
514 goto out;
515 }
516 }
517
518cow:
519 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
520
521 nfrags = skb_cow_data(skb, tailen, &trailer);
522 if (nfrags < 0)
523 goto out;
524 tail = skb_tail_pointer(trailer);
525 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
526
527skip_cow:
528 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
529 pskb_put(skb, trailer, tailen);
530
531out:
532 return nfrags;
533}
534EXPORT_SYMBOL_GPL(esp6_output_head);
535
536int esp6_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
537{
538 u8 *iv;
539 int alen;
540 void *tmp;
541 int ivlen;
542 int assoclen;
543 int extralen;
544 struct page *page;
545 struct ip_esp_hdr *esph;
546 struct aead_request *req;
547 struct crypto_aead *aead;
548 struct scatterlist *sg, *dsg;
549 struct esp_output_extra *extra;
550 int err = -ENOMEM;
551
552 assoclen = sizeof(struct ip_esp_hdr);
553 extralen = 0;
554
555 if (x->props.flags & XFRM_STATE_ESN) {
556 extralen += sizeof(*extra);
557 assoclen += sizeof(__be32);
558 }
559
560 aead = x->data;
561 alen = crypto_aead_authsize(aead);
562 ivlen = crypto_aead_ivsize(aead);
563
564 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
565 if (!tmp)
566 goto error;
567
568 extra = esp_tmp_extra(tmp);
569 iv = esp_tmp_iv(aead, tmp, extralen);
570 req = esp_tmp_req(aead, iv);
571 sg = esp_req_sg(aead, req);
572
573 if (esp->inplace)
574 dsg = sg;
575 else
576 dsg = &sg[esp->nfrags];
577
578 esph = esp_output_set_esn(skb, x, esp->esph, extra);
579 esp->esph = esph;
580
581 sg_init_table(sg, esp->nfrags);
582 err = skb_to_sgvec(skb, sg,
583 (unsigned char *)esph - skb->data,
584 assoclen + ivlen + esp->clen + alen);
585 if (unlikely(err < 0))
586 goto error_free;
587
588 if (!esp->inplace) {
589 int allocsize;
590 struct page_frag *pfrag = &x->xfrag;
591
592 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
593
594 spin_lock_bh(&x->lock);
595 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
596 spin_unlock_bh(&x->lock);
597 goto error_free;
598 }
599
600 skb_shinfo(skb)->nr_frags = 1;
601
602 page = pfrag->page;
603 get_page(page);
604 /* replace page frags in skb with new page */
605 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
606 pfrag->offset = pfrag->offset + allocsize;
607 spin_unlock_bh(&x->lock);
608
609 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
610 err = skb_to_sgvec(skb, dsg,
611 (unsigned char *)esph - skb->data,
612 assoclen + ivlen + esp->clen + alen);
613 if (unlikely(err < 0)) {
614 esp_ssg_unref(x, tmp, skb, true);
615 goto error_free;
616 }
617 }
618
619 if ((x->props.flags & XFRM_STATE_ESN))
620 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
621 else
622 aead_request_set_callback(req, 0, esp_output_done, skb);
623
624 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
625 aead_request_set_ad(req, assoclen);
626
627 memset(iv, 0, ivlen);
628 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
629 min(ivlen, 8));
630
631 ESP_SKB_CB(skb)->tmp = tmp;
632 err = crypto_aead_encrypt(req);
633
634 switch (err) {
635 case -EINPROGRESS:
636 goto error;
637
638 case -ENOSPC:
639 err = NET_XMIT_DROP;
640 break;
641
642 case 0:
643 if ((x->props.flags & XFRM_STATE_ESN))
644 esp_output_restore_header(skb);
645 esp_output_encap_csum(skb);
646 }
647
648 if (sg != dsg)
649 esp_ssg_unref(x, tmp, skb, false);
650
651 if (!err && x->encap && x->encap->encap_type == TCP_ENCAP_ESPINTCP)
652 err = esp_output_tail_tcp(x, skb);
653
654error_free:
655 kfree(tmp);
656error:
657 return err;
658}
659EXPORT_SYMBOL_GPL(esp6_output_tail);
660
661static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
662{
663 int alen;
664 int blksize;
665 struct ip_esp_hdr *esph;
666 struct crypto_aead *aead;
667 struct esp_info esp;
668
669 esp.inplace = true;
670
671 esp.proto = *skb_mac_header(skb);
672 *skb_mac_header(skb) = IPPROTO_ESP;
673
674 /* skb is pure payload to encrypt */
675
676 aead = x->data;
677 alen = crypto_aead_authsize(aead);
678
679 esp.tfclen = 0;
680 if (x->tfcpad) {
681 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
682 u32 padto;
683
684 padto = min(x->tfcpad, xfrm_state_mtu(x, dst->child_mtu_cached));
685 if (skb->len < padto)
686 esp.tfclen = padto - skb->len;
687 }
688 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
689 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
690 esp.plen = esp.clen - skb->len - esp.tfclen;
691 esp.tailen = esp.tfclen + esp.plen + alen;
692
693 esp.esph = ip_esp_hdr(skb);
694
695 esp.nfrags = esp6_output_head(x, skb, &esp);
696 if (esp.nfrags < 0)
697 return esp.nfrags;
698
699 esph = esp.esph;
700 esph->spi = x->id.spi;
701
702 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
703 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
704 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
705
706 skb_push(skb, -skb_network_offset(skb));
707
708 return esp6_output_tail(x, skb, &esp);
709}
710
711static inline int esp_remove_trailer(struct sk_buff *skb)
712{
713 struct xfrm_state *x = xfrm_input_state(skb);
714 struct crypto_aead *aead = x->data;
715 int alen, hlen, elen;
716 int padlen, trimlen;
717 __wsum csumdiff;
718 u8 nexthdr[2];
719 int ret;
720
721 alen = crypto_aead_authsize(aead);
722 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
723 elen = skb->len - hlen;
724
725 ret = skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2);
726 BUG_ON(ret);
727
728 ret = -EINVAL;
729 padlen = nexthdr[0];
730 if (padlen + 2 + alen >= elen) {
731 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
732 padlen + 2, elen - alen);
733 goto out;
734 }
735
736 trimlen = alen + padlen + 2;
737 if (skb->ip_summed == CHECKSUM_COMPLETE) {
738 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
739 skb->csum = csum_block_sub(skb->csum, csumdiff,
740 skb->len - trimlen);
741 }
742 ret = pskb_trim(skb, skb->len - trimlen);
743 if (unlikely(ret))
744 return ret;
745
746 ret = nexthdr[1];
747
748out:
749 return ret;
750}
751
752int esp6_input_done2(struct sk_buff *skb, int err)
753{
754 struct xfrm_state *x = xfrm_input_state(skb);
755 struct xfrm_offload *xo = xfrm_offload(skb);
756 struct crypto_aead *aead = x->data;
757 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
758 int hdr_len = skb_network_header_len(skb);
759
760 if (!xo || !(xo->flags & CRYPTO_DONE))
761 kfree(ESP_SKB_CB(skb)->tmp);
762
763 if (unlikely(err))
764 goto out;
765
766 err = esp_remove_trailer(skb);
767 if (unlikely(err < 0))
768 goto out;
769
770 if (x->encap) {
771 const struct ipv6hdr *ip6h = ipv6_hdr(skb);
772 int offset = skb_network_offset(skb) + sizeof(*ip6h);
773 struct xfrm_encap_tmpl *encap = x->encap;
774 u8 nexthdr = ip6h->nexthdr;
775 __be16 frag_off, source;
776 struct udphdr *uh;
777 struct tcphdr *th;
778
779 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off);
780 if (offset == -1) {
781 err = -EINVAL;
782 goto out;
783 }
784
785 uh = (void *)(skb->data + offset);
786 th = (void *)(skb->data + offset);
787 hdr_len += offset;
788
789 switch (x->encap->encap_type) {
790 case TCP_ENCAP_ESPINTCP:
791 source = th->source;
792 break;
793 case UDP_ENCAP_ESPINUDP:
794 source = uh->source;
795 break;
796 default:
797 WARN_ON_ONCE(1);
798 err = -EINVAL;
799 goto out;
800 }
801
802 /*
803 * 1) if the NAT-T peer's IP or port changed then
804 * advertise the change to the keying daemon.
805 * This is an inbound SA, so just compare
806 * SRC ports.
807 */
808 if (!ipv6_addr_equal(&ip6h->saddr, &x->props.saddr.in6) ||
809 source != encap->encap_sport) {
810 xfrm_address_t ipaddr;
811
812 memcpy(&ipaddr.a6, &ip6h->saddr.s6_addr, sizeof(ipaddr.a6));
813 km_new_mapping(x, &ipaddr, source);
814
815 /* XXX: perhaps add an extra
816 * policy check here, to see
817 * if we should allow or
818 * reject a packet from a
819 * different source
820 * address/port.
821 */
822 }
823
824 /*
825 * 2) ignore UDP/TCP checksums in case
826 * of NAT-T in Transport Mode, or
827 * perform other post-processing fixes
828 * as per draft-ietf-ipsec-udp-encaps-06,
829 * section 3.1.2
830 */
831 if (x->props.mode == XFRM_MODE_TRANSPORT)
832 skb->ip_summed = CHECKSUM_UNNECESSARY;
833 }
834
835 skb_postpull_rcsum(skb, skb_network_header(skb),
836 skb_network_header_len(skb));
837 skb_pull_rcsum(skb, hlen);
838 if (x->props.mode == XFRM_MODE_TUNNEL ||
839 x->props.mode == XFRM_MODE_IPTFS)
840 skb_reset_transport_header(skb);
841 else
842 skb_set_transport_header(skb, -hdr_len);
843
844 /* RFC4303: Drop dummy packets without any error */
845 if (err == IPPROTO_NONE)
846 err = -EINVAL;
847
848out:
849 return err;
850}
851EXPORT_SYMBOL_GPL(esp6_input_done2);
852
853static void esp_input_done(void *data, int err)
854{
855 struct sk_buff *skb = data;
856
857 xfrm_input_resume(skb, esp6_input_done2(skb, err));
858}
859
860static void esp_input_restore_header(struct sk_buff *skb)
861{
862 esp_restore_header(skb, 0);
863 __skb_pull(skb, 4);
864}
865
866static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
867{
868 struct xfrm_state *x = xfrm_input_state(skb);
869
870 /* For ESN we move the header forward by 4 bytes to
871 * accommodate the high bits. We will move it back after
872 * decryption.
873 */
874 if ((x->props.flags & XFRM_STATE_ESN)) {
875 struct ip_esp_hdr *esph = skb_push(skb, 4);
876
877 *seqhi = esph->spi;
878 esph->spi = esph->seq_no;
879 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
880 }
881}
882
883static void esp_input_done_esn(void *data, int err)
884{
885 struct sk_buff *skb = data;
886
887 esp_input_restore_header(skb);
888 esp_input_done(data, err);
889}
890
891static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
892{
893 struct crypto_aead *aead = x->data;
894 struct aead_request *req;
895 struct sk_buff *trailer;
896 int ivlen = crypto_aead_ivsize(aead);
897 int elen = skb->len - sizeof(struct ip_esp_hdr) - ivlen;
898 int nfrags;
899 int assoclen;
900 int seqhilen;
901 int ret = 0;
902 void *tmp;
903 __be32 *seqhi;
904 u8 *iv;
905 struct scatterlist *sg;
906
907 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr) + ivlen)) {
908 ret = -EINVAL;
909 goto out;
910 }
911
912 if (elen <= 0) {
913 ret = -EINVAL;
914 goto out;
915 }
916
917 assoclen = sizeof(struct ip_esp_hdr);
918 seqhilen = 0;
919
920 if (x->props.flags & XFRM_STATE_ESN) {
921 seqhilen += sizeof(__be32);
922 assoclen += seqhilen;
923 }
924
925 if (!skb_cloned(skb)) {
926 if (!skb_is_nonlinear(skb)) {
927 nfrags = 1;
928
929 goto skip_cow;
930 } else if (!skb_has_frag_list(skb) &&
931 !skb_has_shared_frag(skb)) {
932 nfrags = skb_shinfo(skb)->nr_frags;
933 nfrags++;
934
935 goto skip_cow;
936 }
937 }
938
939 nfrags = skb_cow_data(skb, 0, &trailer);
940 if (nfrags < 0) {
941 ret = -EINVAL;
942 goto out;
943 }
944
945skip_cow:
946 ret = -ENOMEM;
947 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
948 if (!tmp)
949 goto out;
950
951 ESP_SKB_CB(skb)->tmp = tmp;
952 seqhi = esp_tmp_extra(tmp);
953 iv = esp_tmp_iv(aead, tmp, seqhilen);
954 req = esp_tmp_req(aead, iv);
955 sg = esp_req_sg(aead, req);
956
957 esp_input_set_header(skb, seqhi);
958
959 sg_init_table(sg, nfrags);
960 ret = skb_to_sgvec(skb, sg, 0, skb->len);
961 if (unlikely(ret < 0)) {
962 kfree(tmp);
963 goto out;
964 }
965
966 skb->ip_summed = CHECKSUM_NONE;
967
968 if ((x->props.flags & XFRM_STATE_ESN))
969 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
970 else
971 aead_request_set_callback(req, 0, esp_input_done, skb);
972
973 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
974 aead_request_set_ad(req, assoclen);
975
976 ret = crypto_aead_decrypt(req);
977 if (ret == -EINPROGRESS)
978 goto out;
979
980 if ((x->props.flags & XFRM_STATE_ESN))
981 esp_input_restore_header(skb);
982
983 ret = esp6_input_done2(skb, ret);
984
985out:
986 return ret;
987}
988
989static int esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
990 u8 type, u8 code, int offset, __be32 info)
991{
992 struct net *net = dev_net(skb->dev);
993 const struct ipv6hdr *iph = (const struct ipv6hdr *)skb->data;
994 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
995 struct xfrm_state *x;
996
997 if (type != ICMPV6_PKT_TOOBIG &&
998 type != NDISC_REDIRECT)
999 return 0;
1000
1001 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
1002 esph->spi, IPPROTO_ESP, AF_INET6);
1003 if (!x)
1004 return 0;
1005
1006 if (type == NDISC_REDIRECT)
1007 ip6_redirect(skb, net, skb->dev->ifindex, 0,
1008 sock_net_uid(net, NULL));
1009 else
1010 ip6_update_pmtu(skb, net, info, 0, 0, sock_net_uid(net, NULL));
1011 xfrm_state_put(x);
1012
1013 return 0;
1014}
1015
1016static void esp6_destroy(struct xfrm_state *x)
1017{
1018 struct crypto_aead *aead = x->data;
1019
1020 if (!aead)
1021 return;
1022
1023 crypto_free_aead(aead);
1024}
1025
1026static int esp_init_aead(struct xfrm_state *x, struct netlink_ext_ack *extack)
1027{
1028 char aead_name[CRYPTO_MAX_ALG_NAME];
1029 struct crypto_aead *aead;
1030 int err;
1031
1032 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
1033 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME) {
1034 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1035 return -ENAMETOOLONG;
1036 }
1037
1038 aead = crypto_alloc_aead(aead_name, 0, 0);
1039 err = PTR_ERR(aead);
1040 if (IS_ERR(aead))
1041 goto error;
1042
1043 x->data = aead;
1044
1045 err = crypto_aead_setkey(aead, x->aead->alg_key,
1046 (x->aead->alg_key_len + 7) / 8);
1047 if (err)
1048 goto error;
1049
1050 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
1051 if (err)
1052 goto error;
1053
1054 return 0;
1055
1056error:
1057 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1058 return err;
1059}
1060
1061static int esp_init_authenc(struct xfrm_state *x,
1062 struct netlink_ext_ack *extack)
1063{
1064 struct crypto_aead *aead;
1065 struct crypto_authenc_key_param *param;
1066 struct rtattr *rta;
1067 char *key;
1068 char *p;
1069 char authenc_name[CRYPTO_MAX_ALG_NAME];
1070 unsigned int keylen;
1071 int err;
1072
1073 err = -ENAMETOOLONG;
1074
1075 if ((x->props.flags & XFRM_STATE_ESN)) {
1076 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1077 "%s%sauthencesn(%s,%s)%s",
1078 x->geniv ?: "", x->geniv ? "(" : "",
1079 x->aalg ? x->aalg->alg_name : "digest_null",
1080 x->ealg->alg_name,
1081 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1082 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1083 goto error;
1084 }
1085 } else {
1086 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
1087 "%s%sauthenc(%s,%s)%s",
1088 x->geniv ?: "", x->geniv ? "(" : "",
1089 x->aalg ? x->aalg->alg_name : "digest_null",
1090 x->ealg->alg_name,
1091 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME) {
1092 NL_SET_ERR_MSG(extack, "Algorithm name is too long");
1093 goto error;
1094 }
1095 }
1096
1097 aead = crypto_alloc_aead(authenc_name, 0, 0);
1098 err = PTR_ERR(aead);
1099 if (IS_ERR(aead)) {
1100 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1101 goto error;
1102 }
1103
1104 x->data = aead;
1105
1106 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
1107 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
1108 err = -ENOMEM;
1109 key = kmalloc(keylen, GFP_KERNEL);
1110 if (!key)
1111 goto error;
1112
1113 p = key;
1114 rta = (void *)p;
1115 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
1116 rta->rta_len = RTA_LENGTH(sizeof(*param));
1117 param = RTA_DATA(rta);
1118 p += RTA_SPACE(sizeof(*param));
1119
1120 if (x->aalg) {
1121 struct xfrm_algo_desc *aalg_desc;
1122
1123 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
1124 p += (x->aalg->alg_key_len + 7) / 8;
1125
1126 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
1127 BUG_ON(!aalg_desc);
1128
1129 err = -EINVAL;
1130 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
1131 crypto_aead_authsize(aead)) {
1132 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1133 goto free_key;
1134 }
1135
1136 err = crypto_aead_setauthsize(
1137 aead, x->aalg->alg_trunc_len / 8);
1138 if (err) {
1139 NL_SET_ERR_MSG(extack, "Kernel was unable to initialize cryptographic operations");
1140 goto free_key;
1141 }
1142 }
1143
1144 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
1145 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
1146
1147 err = crypto_aead_setkey(aead, key, keylen);
1148
1149free_key:
1150 kfree(key);
1151
1152error:
1153 return err;
1154}
1155
1156static int esp6_init_state(struct xfrm_state *x, struct netlink_ext_ack *extack)
1157{
1158 struct crypto_aead *aead;
1159 u32 align;
1160 int err;
1161
1162 x->data = NULL;
1163
1164 if (x->aead) {
1165 err = esp_init_aead(x, extack);
1166 } else if (x->ealg) {
1167 err = esp_init_authenc(x, extack);
1168 } else {
1169 NL_SET_ERR_MSG(extack, "ESP: AEAD or CRYPT must be provided");
1170 err = -EINVAL;
1171 }
1172
1173 if (err)
1174 goto error;
1175
1176 aead = x->data;
1177
1178 x->props.header_len = sizeof(struct ip_esp_hdr) +
1179 crypto_aead_ivsize(aead);
1180 switch (x->props.mode) {
1181 case XFRM_MODE_BEET:
1182 if (x->sel.family != AF_INET6)
1183 x->props.header_len += IPV4_BEET_PHMAXLEN +
1184 (sizeof(struct ipv6hdr) - sizeof(struct iphdr));
1185 break;
1186 default:
1187 case XFRM_MODE_TRANSPORT:
1188 break;
1189 case XFRM_MODE_TUNNEL:
1190 x->props.header_len += sizeof(struct ipv6hdr);
1191 break;
1192 }
1193
1194 if (x->encap) {
1195 struct xfrm_encap_tmpl *encap = x->encap;
1196
1197 switch (encap->encap_type) {
1198 default:
1199 NL_SET_ERR_MSG(extack, "Unsupported encapsulation type for ESP");
1200 err = -EINVAL;
1201 goto error;
1202 case UDP_ENCAP_ESPINUDP:
1203 x->props.header_len += sizeof(struct udphdr);
1204 break;
1205#ifdef CONFIG_INET6_ESPINTCP
1206 case TCP_ENCAP_ESPINTCP:
1207 /* only the length field, TCP encap is done by
1208 * the socket
1209 */
1210 x->props.header_len += 2;
1211 break;
1212#endif
1213 }
1214 }
1215
1216 align = ALIGN(crypto_aead_blocksize(aead), 4);
1217 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1218
1219error:
1220 return err;
1221}
1222
1223static int esp6_rcv_cb(struct sk_buff *skb, int err)
1224{
1225 return 0;
1226}
1227
1228static const struct xfrm_type esp6_type = {
1229 .owner = THIS_MODULE,
1230 .proto = IPPROTO_ESP,
1231 .flags = XFRM_TYPE_REPLAY_PROT,
1232 .init_state = esp6_init_state,
1233 .destructor = esp6_destroy,
1234 .input = esp6_input,
1235 .output = esp6_output,
1236};
1237
1238static struct xfrm6_protocol esp6_protocol = {
1239 .handler = xfrm6_rcv,
1240 .input_handler = xfrm_input,
1241 .cb_handler = esp6_rcv_cb,
1242 .err_handler = esp6_err,
1243 .priority = 0,
1244};
1245
1246static int __init esp6_init(void)
1247{
1248 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
1249 pr_info("%s: can't add xfrm type\n", __func__);
1250 return -EAGAIN;
1251 }
1252 if (xfrm6_protocol_register(&esp6_protocol, IPPROTO_ESP) < 0) {
1253 pr_info("%s: can't add protocol\n", __func__);
1254 xfrm_unregister_type(&esp6_type, AF_INET6);
1255 return -EAGAIN;
1256 }
1257
1258 return 0;
1259}
1260
1261static void __exit esp6_fini(void)
1262{
1263 if (xfrm6_protocol_deregister(&esp6_protocol, IPPROTO_ESP) < 0)
1264 pr_info("%s: can't remove protocol\n", __func__);
1265 xfrm_unregister_type(&esp6_type, AF_INET6);
1266}
1267
1268module_init(esp6_init);
1269module_exit(esp6_fini);
1270
1271MODULE_DESCRIPTION("IPv6 ESP transformation helpers");
1272MODULE_LICENSE("GPL");
1273MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);