1 #define pr_fmt(fmt) "IPsec: " fmt
2
3 #include <crypto/aead.h>
4 #include <crypto/authenc.h>
5 #include <linux/err.h>
6 #include <linux/module.h>
7 #include <net/ip.h>
8 #include <net/xfrm.h>
9 #include <net/esp.h>
10 #include <linux/scatterlist.h>
11 #include <linux/kernel.h>
12 #include <linux/pfkeyv2.h>
13 #include <linux/rtnetlink.h>
14 #include <linux/slab.h>
15 #include <linux/spinlock.h>
16 #include <linux/in6.h>
17 #include <net/icmp.h>
18 #include <net/protocol.h>
19 #include <net/udp.h>
20
21 #include <linux/highmem.h>
22
23 struct esp_skb_cb {
24 struct xfrm_skb_cb xfrm;
25 void *tmp;
26 };
27
28 struct esp_output_extra {
29 __be32 seqhi;
30 u32 esphoff;
31 };
32
33 #define ESP_SKB_CB(__skb) ((struct esp_skb_cb *)&((__skb)->cb[0]))
34
35 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu);
36
37 /*
38 * Allocate an AEAD request structure with extra space for SG and IV.
39 *
40 * For alignment considerations the IV is placed at the front, followed
41 * by the request and finally the SG list.
42 *
43 * TODO: Use spare space in skb for this where possible.
44 */
esp_alloc_tmp(struct crypto_aead * aead,int nfrags,int extralen)45 static void *esp_alloc_tmp(struct crypto_aead *aead, int nfrags, int extralen)
46 {
47 unsigned int len;
48
49 len = extralen;
50
51 len += crypto_aead_ivsize(aead);
52
53 if (len) {
54 len += crypto_aead_alignmask(aead) &
55 ~(crypto_tfm_ctx_alignment() - 1);
56 len = ALIGN(len, crypto_tfm_ctx_alignment());
57 }
58
59 len += sizeof(struct aead_request) + crypto_aead_reqsize(aead);
60 len = ALIGN(len, __alignof__(struct scatterlist));
61
62 len += sizeof(struct scatterlist) * nfrags;
63
64 return kmalloc(len, GFP_ATOMIC);
65 }
66
esp_tmp_extra(void * tmp)67 static inline void *esp_tmp_extra(void *tmp)
68 {
69 return PTR_ALIGN(tmp, __alignof__(struct esp_output_extra));
70 }
71
esp_tmp_iv(struct crypto_aead * aead,void * tmp,int extralen)72 static inline u8 *esp_tmp_iv(struct crypto_aead *aead, void *tmp, int extralen)
73 {
74 return crypto_aead_ivsize(aead) ?
75 PTR_ALIGN((u8 *)tmp + extralen,
76 crypto_aead_alignmask(aead) + 1) : tmp + extralen;
77 }
78
esp_tmp_req(struct crypto_aead * aead,u8 * iv)79 static inline struct aead_request *esp_tmp_req(struct crypto_aead *aead, u8 *iv)
80 {
81 struct aead_request *req;
82
83 req = (void *)PTR_ALIGN(iv + crypto_aead_ivsize(aead),
84 crypto_tfm_ctx_alignment());
85 aead_request_set_tfm(req, aead);
86 return req;
87 }
88
esp_req_sg(struct crypto_aead * aead,struct aead_request * req)89 static inline struct scatterlist *esp_req_sg(struct crypto_aead *aead,
90 struct aead_request *req)
91 {
92 return (void *)ALIGN((unsigned long)(req + 1) +
93 crypto_aead_reqsize(aead),
94 __alignof__(struct scatterlist));
95 }
96
esp_ssg_unref(struct xfrm_state * x,void * tmp)97 static void esp_ssg_unref(struct xfrm_state *x, void *tmp)
98 {
99 struct esp_output_extra *extra = esp_tmp_extra(tmp);
100 struct crypto_aead *aead = x->data;
101 int extralen = 0;
102 u8 *iv;
103 struct aead_request *req;
104 struct scatterlist *sg;
105
106 if (x->props.flags & XFRM_STATE_ESN)
107 extralen += sizeof(*extra);
108
109 extra = esp_tmp_extra(tmp);
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 put_page(sg_page(sg));
119 }
120
esp_output_done(struct crypto_async_request * base,int err)121 static void esp_output_done(struct crypto_async_request *base, int err)
122 {
123 struct sk_buff *skb = base->data;
124 struct xfrm_offload *xo = xfrm_offload(skb);
125 void *tmp;
126 struct xfrm_state *x;
127
128 if (xo && (xo->flags & XFRM_DEV_RESUME))
129 x = skb->sp->xvec[skb->sp->len - 1];
130 else
131 x = skb_dst(skb)->xfrm;
132
133 tmp = ESP_SKB_CB(skb)->tmp;
134 esp_ssg_unref(x, tmp);
135 kfree(tmp);
136
137 if (xo && (xo->flags & XFRM_DEV_RESUME)) {
138 if (err) {
139 XFRM_INC_STATS(xs_net(x), LINUX_MIB_XFRMOUTSTATEPROTOERROR);
140 kfree_skb(skb);
141 return;
142 }
143
144 skb_push(skb, skb->data - skb_mac_header(skb));
145 secpath_reset(skb);
146 xfrm_dev_resume(skb);
147 } else {
148 xfrm_output_resume(skb, err);
149 }
150 }
151
152 /* Move ESP header back into place. */
esp_restore_header(struct sk_buff * skb,unsigned int offset)153 static void esp_restore_header(struct sk_buff *skb, unsigned int offset)
154 {
155 struct ip_esp_hdr *esph = (void *)(skb->data + offset);
156 void *tmp = ESP_SKB_CB(skb)->tmp;
157 __be32 *seqhi = esp_tmp_extra(tmp);
158
159 esph->seq_no = esph->spi;
160 esph->spi = *seqhi;
161 }
162
esp_output_restore_header(struct sk_buff * skb)163 static void esp_output_restore_header(struct sk_buff *skb)
164 {
165 void *tmp = ESP_SKB_CB(skb)->tmp;
166 struct esp_output_extra *extra = esp_tmp_extra(tmp);
167
168 esp_restore_header(skb, skb_transport_offset(skb) + extra->esphoff -
169 sizeof(__be32));
170 }
171
esp_output_set_extra(struct sk_buff * skb,struct xfrm_state * x,struct ip_esp_hdr * esph,struct esp_output_extra * extra)172 static struct ip_esp_hdr *esp_output_set_extra(struct sk_buff *skb,
173 struct xfrm_state *x,
174 struct ip_esp_hdr *esph,
175 struct esp_output_extra *extra)
176 {
177 /* For ESN we move the header forward by 4 bytes to
178 * accomodate the high bits. We will move it back after
179 * encryption.
180 */
181 if ((x->props.flags & XFRM_STATE_ESN)) {
182 __u32 seqhi;
183 struct xfrm_offload *xo = xfrm_offload(skb);
184
185 if (xo)
186 seqhi = xo->seq.hi;
187 else
188 seqhi = XFRM_SKB_CB(skb)->seq.output.hi;
189
190 extra->esphoff = (unsigned char *)esph -
191 skb_transport_header(skb);
192 esph = (struct ip_esp_hdr *)((unsigned char *)esph - 4);
193 extra->seqhi = esph->spi;
194 esph->seq_no = htonl(seqhi);
195 }
196
197 esph->spi = x->id.spi;
198
199 return esph;
200 }
201
esp_output_done_esn(struct crypto_async_request * base,int err)202 static void esp_output_done_esn(struct crypto_async_request *base, int err)
203 {
204 struct sk_buff *skb = base->data;
205
206 esp_output_restore_header(skb);
207 esp_output_done(base, err);
208 }
209
esp_output_fill_trailer(u8 * tail,int tfclen,int plen,__u8 proto)210 static void esp_output_fill_trailer(u8 *tail, int tfclen, int plen, __u8 proto)
211 {
212 /* Fill padding... */
213 if (tfclen) {
214 memset(tail, 0, tfclen);
215 tail += tfclen;
216 }
217 do {
218 int i;
219 for (i = 0; i < plen - 2; i++)
220 tail[i] = i + 1;
221 } while (0);
222 tail[plen - 2] = plen - 2;
223 tail[plen - 1] = proto;
224 }
225
esp_output_udp_encap(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)226 static void esp_output_udp_encap(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
227 {
228 int encap_type;
229 struct udphdr *uh;
230 __be32 *udpdata32;
231 __be16 sport, dport;
232 struct xfrm_encap_tmpl *encap = x->encap;
233 struct ip_esp_hdr *esph = esp->esph;
234
235 spin_lock_bh(&x->lock);
236 sport = encap->encap_sport;
237 dport = encap->encap_dport;
238 encap_type = encap->encap_type;
239 spin_unlock_bh(&x->lock);
240
241 uh = (struct udphdr *)esph;
242 uh->source = sport;
243 uh->dest = dport;
244 uh->len = htons(skb->len + esp->tailen
245 - skb_transport_offset(skb));
246 uh->check = 0;
247
248 switch (encap_type) {
249 default:
250 case UDP_ENCAP_ESPINUDP:
251 esph = (struct ip_esp_hdr *)(uh + 1);
252 break;
253 case UDP_ENCAP_ESPINUDP_NON_IKE:
254 udpdata32 = (__be32 *)(uh + 1);
255 udpdata32[0] = udpdata32[1] = 0;
256 esph = (struct ip_esp_hdr *)(udpdata32 + 2);
257 break;
258 }
259
260 *skb_mac_header(skb) = IPPROTO_UDP;
261 esp->esph = esph;
262 }
263
esp_output_head(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)264 int esp_output_head(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
265 {
266 u8 *tail;
267 u8 *vaddr;
268 int nfrags;
269 int esph_offset;
270 struct page *page;
271 struct sk_buff *trailer;
272 int tailen = esp->tailen;
273
274 /* this is non-NULL only with UDP Encapsulation */
275 if (x->encap)
276 esp_output_udp_encap(x, skb, esp);
277
278 if (!skb_cloned(skb)) {
279 if (tailen <= skb_tailroom(skb)) {
280 nfrags = 1;
281 trailer = skb;
282 tail = skb_tail_pointer(trailer);
283
284 goto skip_cow;
285 } else if ((skb_shinfo(skb)->nr_frags < MAX_SKB_FRAGS)
286 && !skb_has_frag_list(skb)) {
287 int allocsize;
288 struct sock *sk = skb->sk;
289 struct page_frag *pfrag = &x->xfrag;
290
291 esp->inplace = false;
292
293 allocsize = ALIGN(tailen, L1_CACHE_BYTES);
294
295 spin_lock_bh(&x->lock);
296
297 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
298 spin_unlock_bh(&x->lock);
299 goto cow;
300 }
301
302 page = pfrag->page;
303 get_page(page);
304
305 vaddr = kmap_atomic(page);
306
307 tail = vaddr + pfrag->offset;
308
309 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
310
311 kunmap_atomic(vaddr);
312
313 nfrags = skb_shinfo(skb)->nr_frags;
314
315 __skb_fill_page_desc(skb, nfrags, page, pfrag->offset,
316 tailen);
317 skb_shinfo(skb)->nr_frags = ++nfrags;
318
319 pfrag->offset = pfrag->offset + allocsize;
320
321 spin_unlock_bh(&x->lock);
322
323 nfrags++;
324
325 skb->len += tailen;
326 skb->data_len += tailen;
327 skb->truesize += tailen;
328 if (sk)
329 refcount_add(tailen, &sk->sk_wmem_alloc);
330
331 goto out;
332 }
333 }
334
335 cow:
336 esph_offset = (unsigned char *)esp->esph - skb_transport_header(skb);
337
338 nfrags = skb_cow_data(skb, tailen, &trailer);
339 if (nfrags < 0)
340 goto out;
341 tail = skb_tail_pointer(trailer);
342 esp->esph = (struct ip_esp_hdr *)(skb_transport_header(skb) + esph_offset);
343
344 skip_cow:
345 esp_output_fill_trailer(tail, esp->tfclen, esp->plen, esp->proto);
346 pskb_put(skb, trailer, tailen);
347
348 out:
349 return nfrags;
350 }
351 EXPORT_SYMBOL_GPL(esp_output_head);
352
esp_output_tail(struct xfrm_state * x,struct sk_buff * skb,struct esp_info * esp)353 int esp_output_tail(struct xfrm_state *x, struct sk_buff *skb, struct esp_info *esp)
354 {
355 u8 *iv;
356 int alen;
357 void *tmp;
358 int ivlen;
359 int assoclen;
360 int extralen;
361 struct page *page;
362 struct ip_esp_hdr *esph;
363 struct crypto_aead *aead;
364 struct aead_request *req;
365 struct scatterlist *sg, *dsg;
366 struct esp_output_extra *extra;
367 int err = -ENOMEM;
368
369 assoclen = sizeof(struct ip_esp_hdr);
370 extralen = 0;
371
372 if (x->props.flags & XFRM_STATE_ESN) {
373 extralen += sizeof(*extra);
374 assoclen += sizeof(__be32);
375 }
376
377 aead = x->data;
378 alen = crypto_aead_authsize(aead);
379 ivlen = crypto_aead_ivsize(aead);
380
381 tmp = esp_alloc_tmp(aead, esp->nfrags + 2, extralen);
382 if (!tmp)
383 goto error;
384
385 extra = esp_tmp_extra(tmp);
386 iv = esp_tmp_iv(aead, tmp, extralen);
387 req = esp_tmp_req(aead, iv);
388 sg = esp_req_sg(aead, req);
389
390 if (esp->inplace)
391 dsg = sg;
392 else
393 dsg = &sg[esp->nfrags];
394
395 esph = esp_output_set_extra(skb, x, esp->esph, extra);
396 esp->esph = esph;
397
398 sg_init_table(sg, esp->nfrags);
399 err = skb_to_sgvec(skb, sg,
400 (unsigned char *)esph - skb->data,
401 assoclen + ivlen + esp->clen + alen);
402 if (unlikely(err < 0))
403 goto error_free;
404
405 if (!esp->inplace) {
406 int allocsize;
407 struct page_frag *pfrag = &x->xfrag;
408
409 allocsize = ALIGN(skb->data_len, L1_CACHE_BYTES);
410
411 spin_lock_bh(&x->lock);
412 if (unlikely(!skb_page_frag_refill(allocsize, pfrag, GFP_ATOMIC))) {
413 spin_unlock_bh(&x->lock);
414 goto error_free;
415 }
416
417 skb_shinfo(skb)->nr_frags = 1;
418
419 page = pfrag->page;
420 get_page(page);
421 /* replace page frags in skb with new page */
422 __skb_fill_page_desc(skb, 0, page, pfrag->offset, skb->data_len);
423 pfrag->offset = pfrag->offset + allocsize;
424 spin_unlock_bh(&x->lock);
425
426 sg_init_table(dsg, skb_shinfo(skb)->nr_frags + 1);
427 err = skb_to_sgvec(skb, dsg,
428 (unsigned char *)esph - skb->data,
429 assoclen + ivlen + esp->clen + alen);
430 if (unlikely(err < 0))
431 goto error_free;
432 }
433
434 if ((x->props.flags & XFRM_STATE_ESN))
435 aead_request_set_callback(req, 0, esp_output_done_esn, skb);
436 else
437 aead_request_set_callback(req, 0, esp_output_done, skb);
438
439 aead_request_set_crypt(req, sg, dsg, ivlen + esp->clen, iv);
440 aead_request_set_ad(req, assoclen);
441
442 memset(iv, 0, ivlen);
443 memcpy(iv + ivlen - min(ivlen, 8), (u8 *)&esp->seqno + 8 - min(ivlen, 8),
444 min(ivlen, 8));
445
446 ESP_SKB_CB(skb)->tmp = tmp;
447 err = crypto_aead_encrypt(req);
448
449 switch (err) {
450 case -EINPROGRESS:
451 goto error;
452
453 case -ENOSPC:
454 err = NET_XMIT_DROP;
455 break;
456
457 case 0:
458 if ((x->props.flags & XFRM_STATE_ESN))
459 esp_output_restore_header(skb);
460 }
461
462 if (sg != dsg)
463 esp_ssg_unref(x, tmp);
464
465 error_free:
466 kfree(tmp);
467 error:
468 return err;
469 }
470 EXPORT_SYMBOL_GPL(esp_output_tail);
471
esp_output(struct xfrm_state * x,struct sk_buff * skb)472 static int esp_output(struct xfrm_state *x, struct sk_buff *skb)
473 {
474 int alen;
475 int blksize;
476 struct ip_esp_hdr *esph;
477 struct crypto_aead *aead;
478 struct esp_info esp;
479
480 esp.inplace = true;
481
482 esp.proto = *skb_mac_header(skb);
483 *skb_mac_header(skb) = IPPROTO_ESP;
484
485 /* skb is pure payload to encrypt */
486
487 aead = x->data;
488 alen = crypto_aead_authsize(aead);
489
490 esp.tfclen = 0;
491 if (x->tfcpad) {
492 struct xfrm_dst *dst = (struct xfrm_dst *)skb_dst(skb);
493 u32 padto;
494
495 padto = min(x->tfcpad, esp4_get_mtu(x, dst->child_mtu_cached));
496 if (skb->len < padto)
497 esp.tfclen = padto - skb->len;
498 }
499 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
500 esp.clen = ALIGN(skb->len + 2 + esp.tfclen, blksize);
501 esp.plen = esp.clen - skb->len - esp.tfclen;
502 esp.tailen = esp.tfclen + esp.plen + alen;
503
504 esp.esph = ip_esp_hdr(skb);
505
506 esp.nfrags = esp_output_head(x, skb, &esp);
507 if (esp.nfrags < 0)
508 return esp.nfrags;
509
510 esph = esp.esph;
511 esph->spi = x->id.spi;
512
513 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
514 esp.seqno = cpu_to_be64(XFRM_SKB_CB(skb)->seq.output.low +
515 ((u64)XFRM_SKB_CB(skb)->seq.output.hi << 32));
516
517 skb_push(skb, -skb_network_offset(skb));
518
519 return esp_output_tail(x, skb, &esp);
520 }
521
esp_remove_trailer(struct sk_buff * skb)522 static inline int esp_remove_trailer(struct sk_buff *skb)
523 {
524 struct xfrm_state *x = xfrm_input_state(skb);
525 struct xfrm_offload *xo = xfrm_offload(skb);
526 struct crypto_aead *aead = x->data;
527 int alen, hlen, elen;
528 int padlen, trimlen;
529 __wsum csumdiff;
530 u8 nexthdr[2];
531 int ret;
532
533 alen = crypto_aead_authsize(aead);
534 hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
535 elen = skb->len - hlen;
536
537 if (xo && (xo->flags & XFRM_ESP_NO_TRAILER)) {
538 ret = xo->proto;
539 goto out;
540 }
541
542 if (skb_copy_bits(skb, skb->len - alen - 2, nexthdr, 2))
543 BUG();
544
545 ret = -EINVAL;
546 padlen = nexthdr[0];
547 if (padlen + 2 + alen >= elen) {
548 net_dbg_ratelimited("ipsec esp packet is garbage padlen=%d, elen=%d\n",
549 padlen + 2, elen - alen);
550 goto out;
551 }
552
553 trimlen = alen + padlen + 2;
554 if (skb->ip_summed == CHECKSUM_COMPLETE) {
555 csumdiff = skb_checksum(skb, skb->len - trimlen, trimlen, 0);
556 skb->csum = csum_block_sub(skb->csum, csumdiff,
557 skb->len - trimlen);
558 }
559 pskb_trim(skb, skb->len - trimlen);
560
561 ret = nexthdr[1];
562
563 out:
564 return ret;
565 }
566
esp_input_done2(struct sk_buff * skb,int err)567 int esp_input_done2(struct sk_buff *skb, int err)
568 {
569 const struct iphdr *iph;
570 struct xfrm_state *x = xfrm_input_state(skb);
571 struct xfrm_offload *xo = xfrm_offload(skb);
572 struct crypto_aead *aead = x->data;
573 int hlen = sizeof(struct ip_esp_hdr) + crypto_aead_ivsize(aead);
574 int ihl;
575
576 if (!xo || (xo && !(xo->flags & CRYPTO_DONE)))
577 kfree(ESP_SKB_CB(skb)->tmp);
578
579 if (unlikely(err))
580 goto out;
581
582 err = esp_remove_trailer(skb);
583 if (unlikely(err < 0))
584 goto out;
585
586 iph = ip_hdr(skb);
587 ihl = iph->ihl * 4;
588
589 if (x->encap) {
590 struct xfrm_encap_tmpl *encap = x->encap;
591 struct udphdr *uh = (void *)(skb_network_header(skb) + ihl);
592
593 /*
594 * 1) if the NAT-T peer's IP or port changed then
595 * advertize the change to the keying daemon.
596 * This is an inbound SA, so just compare
597 * SRC ports.
598 */
599 if (iph->saddr != x->props.saddr.a4 ||
600 uh->source != encap->encap_sport) {
601 xfrm_address_t ipaddr;
602
603 ipaddr.a4 = iph->saddr;
604 km_new_mapping(x, &ipaddr, uh->source);
605
606 /* XXX: perhaps add an extra
607 * policy check here, to see
608 * if we should allow or
609 * reject a packet from a
610 * different source
611 * address/port.
612 */
613 }
614
615 /*
616 * 2) ignore UDP/TCP checksums in case
617 * of NAT-T in Transport Mode, or
618 * perform other post-processing fixes
619 * as per draft-ietf-ipsec-udp-encaps-06,
620 * section 3.1.2
621 */
622 if (x->props.mode == XFRM_MODE_TRANSPORT)
623 skb->ip_summed = CHECKSUM_UNNECESSARY;
624 }
625
626 skb_pull_rcsum(skb, hlen);
627 if (x->props.mode == XFRM_MODE_TUNNEL)
628 skb_reset_transport_header(skb);
629 else
630 skb_set_transport_header(skb, -ihl);
631
632 /* RFC4303: Drop dummy packets without any error */
633 if (err == IPPROTO_NONE)
634 err = -EINVAL;
635
636 out:
637 return err;
638 }
639 EXPORT_SYMBOL_GPL(esp_input_done2);
640
esp_input_done(struct crypto_async_request * base,int err)641 static void esp_input_done(struct crypto_async_request *base, int err)
642 {
643 struct sk_buff *skb = base->data;
644
645 xfrm_input_resume(skb, esp_input_done2(skb, err));
646 }
647
esp_input_restore_header(struct sk_buff * skb)648 static void esp_input_restore_header(struct sk_buff *skb)
649 {
650 esp_restore_header(skb, 0);
651 __skb_pull(skb, 4);
652 }
653
esp_input_set_header(struct sk_buff * skb,__be32 * seqhi)654 static void esp_input_set_header(struct sk_buff *skb, __be32 *seqhi)
655 {
656 struct xfrm_state *x = xfrm_input_state(skb);
657 struct ip_esp_hdr *esph;
658
659 /* For ESN we move the header forward by 4 bytes to
660 * accomodate the high bits. We will move it back after
661 * decryption.
662 */
663 if ((x->props.flags & XFRM_STATE_ESN)) {
664 esph = skb_push(skb, 4);
665 *seqhi = esph->spi;
666 esph->spi = esph->seq_no;
667 esph->seq_no = XFRM_SKB_CB(skb)->seq.input.hi;
668 }
669 }
670
esp_input_done_esn(struct crypto_async_request * base,int err)671 static void esp_input_done_esn(struct crypto_async_request *base, int err)
672 {
673 struct sk_buff *skb = base->data;
674
675 esp_input_restore_header(skb);
676 esp_input_done(base, err);
677 }
678
679 /*
680 * Note: detecting truncated vs. non-truncated authentication data is very
681 * expensive, so we only support truncated data, which is the recommended
682 * and common case.
683 */
esp_input(struct xfrm_state * x,struct sk_buff * skb)684 static int esp_input(struct xfrm_state *x, struct sk_buff *skb)
685 {
686 struct ip_esp_hdr *esph;
687 struct crypto_aead *aead = x->data;
688 struct aead_request *req;
689 struct sk_buff *trailer;
690 int ivlen = crypto_aead_ivsize(aead);
691 int elen = skb->len - sizeof(*esph) - ivlen;
692 int nfrags;
693 int assoclen;
694 int seqhilen;
695 __be32 *seqhi;
696 void *tmp;
697 u8 *iv;
698 struct scatterlist *sg;
699 int err = -EINVAL;
700
701 if (!pskb_may_pull(skb, sizeof(*esph) + ivlen))
702 goto out;
703
704 if (elen <= 0)
705 goto out;
706
707 assoclen = sizeof(*esph);
708 seqhilen = 0;
709
710 if (x->props.flags & XFRM_STATE_ESN) {
711 seqhilen += sizeof(__be32);
712 assoclen += seqhilen;
713 }
714
715 if (!skb_cloned(skb)) {
716 if (!skb_is_nonlinear(skb)) {
717 nfrags = 1;
718
719 goto skip_cow;
720 } else if (!skb_has_frag_list(skb)) {
721 nfrags = skb_shinfo(skb)->nr_frags;
722 nfrags++;
723
724 goto skip_cow;
725 }
726 }
727
728 err = skb_cow_data(skb, 0, &trailer);
729 if (err < 0)
730 goto out;
731
732 nfrags = err;
733
734 skip_cow:
735 err = -ENOMEM;
736 tmp = esp_alloc_tmp(aead, nfrags, seqhilen);
737 if (!tmp)
738 goto out;
739
740 ESP_SKB_CB(skb)->tmp = tmp;
741 seqhi = esp_tmp_extra(tmp);
742 iv = esp_tmp_iv(aead, tmp, seqhilen);
743 req = esp_tmp_req(aead, iv);
744 sg = esp_req_sg(aead, req);
745
746 esp_input_set_header(skb, seqhi);
747
748 sg_init_table(sg, nfrags);
749 err = skb_to_sgvec(skb, sg, 0, skb->len);
750 if (unlikely(err < 0)) {
751 kfree(tmp);
752 goto out;
753 }
754
755 skb->ip_summed = CHECKSUM_NONE;
756
757 if ((x->props.flags & XFRM_STATE_ESN))
758 aead_request_set_callback(req, 0, esp_input_done_esn, skb);
759 else
760 aead_request_set_callback(req, 0, esp_input_done, skb);
761
762 aead_request_set_crypt(req, sg, sg, elen + ivlen, iv);
763 aead_request_set_ad(req, assoclen);
764
765 err = crypto_aead_decrypt(req);
766 if (err == -EINPROGRESS)
767 goto out;
768
769 if ((x->props.flags & XFRM_STATE_ESN))
770 esp_input_restore_header(skb);
771
772 err = esp_input_done2(skb, err);
773
774 out:
775 return err;
776 }
777
esp4_get_mtu(struct xfrm_state * x,int mtu)778 static u32 esp4_get_mtu(struct xfrm_state *x, int mtu)
779 {
780 struct crypto_aead *aead = x->data;
781 u32 blksize = ALIGN(crypto_aead_blocksize(aead), 4);
782 unsigned int net_adj;
783
784 switch (x->props.mode) {
785 case XFRM_MODE_TRANSPORT:
786 case XFRM_MODE_BEET:
787 net_adj = sizeof(struct iphdr);
788 break;
789 case XFRM_MODE_TUNNEL:
790 net_adj = 0;
791 break;
792 default:
793 BUG();
794 }
795
796 return ((mtu - x->props.header_len - crypto_aead_authsize(aead) -
797 net_adj) & ~(blksize - 1)) + net_adj - 2;
798 }
799
esp4_err(struct sk_buff * skb,u32 info)800 static int esp4_err(struct sk_buff *skb, u32 info)
801 {
802 struct net *net = dev_net(skb->dev);
803 const struct iphdr *iph = (const struct iphdr *)skb->data;
804 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
805 struct xfrm_state *x;
806
807 switch (icmp_hdr(skb)->type) {
808 case ICMP_DEST_UNREACH:
809 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
810 return 0;
811 case ICMP_REDIRECT:
812 break;
813 default:
814 return 0;
815 }
816
817 x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
818 esph->spi, IPPROTO_ESP, AF_INET);
819 if (!x)
820 return 0;
821
822 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
823 ipv4_update_pmtu(skb, net, info, 0, 0, IPPROTO_ESP, 0);
824 else
825 ipv4_redirect(skb, net, 0, 0, IPPROTO_ESP, 0);
826 xfrm_state_put(x);
827
828 return 0;
829 }
830
esp_destroy(struct xfrm_state * x)831 static void esp_destroy(struct xfrm_state *x)
832 {
833 struct crypto_aead *aead = x->data;
834
835 if (!aead)
836 return;
837
838 crypto_free_aead(aead);
839 }
840
esp_init_aead(struct xfrm_state * x)841 static int esp_init_aead(struct xfrm_state *x)
842 {
843 char aead_name[CRYPTO_MAX_ALG_NAME];
844 struct crypto_aead *aead;
845 int err;
846
847 err = -ENAMETOOLONG;
848 if (snprintf(aead_name, CRYPTO_MAX_ALG_NAME, "%s(%s)",
849 x->geniv, x->aead->alg_name) >= CRYPTO_MAX_ALG_NAME)
850 goto error;
851
852 aead = crypto_alloc_aead(aead_name, 0, 0);
853 err = PTR_ERR(aead);
854 if (IS_ERR(aead))
855 goto error;
856
857 x->data = aead;
858
859 err = crypto_aead_setkey(aead, x->aead->alg_key,
860 (x->aead->alg_key_len + 7) / 8);
861 if (err)
862 goto error;
863
864 err = crypto_aead_setauthsize(aead, x->aead->alg_icv_len / 8);
865 if (err)
866 goto error;
867
868 error:
869 return err;
870 }
871
esp_init_authenc(struct xfrm_state * x)872 static int esp_init_authenc(struct xfrm_state *x)
873 {
874 struct crypto_aead *aead;
875 struct crypto_authenc_key_param *param;
876 struct rtattr *rta;
877 char *key;
878 char *p;
879 char authenc_name[CRYPTO_MAX_ALG_NAME];
880 unsigned int keylen;
881 int err;
882
883 err = -EINVAL;
884 if (!x->ealg)
885 goto error;
886
887 err = -ENAMETOOLONG;
888
889 if ((x->props.flags & XFRM_STATE_ESN)) {
890 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
891 "%s%sauthencesn(%s,%s)%s",
892 x->geniv ?: "", x->geniv ? "(" : "",
893 x->aalg ? x->aalg->alg_name : "digest_null",
894 x->ealg->alg_name,
895 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
896 goto error;
897 } else {
898 if (snprintf(authenc_name, CRYPTO_MAX_ALG_NAME,
899 "%s%sauthenc(%s,%s)%s",
900 x->geniv ?: "", x->geniv ? "(" : "",
901 x->aalg ? x->aalg->alg_name : "digest_null",
902 x->ealg->alg_name,
903 x->geniv ? ")" : "") >= CRYPTO_MAX_ALG_NAME)
904 goto error;
905 }
906
907 aead = crypto_alloc_aead(authenc_name, 0, 0);
908 err = PTR_ERR(aead);
909 if (IS_ERR(aead))
910 goto error;
911
912 x->data = aead;
913
914 keylen = (x->aalg ? (x->aalg->alg_key_len + 7) / 8 : 0) +
915 (x->ealg->alg_key_len + 7) / 8 + RTA_SPACE(sizeof(*param));
916 err = -ENOMEM;
917 key = kmalloc(keylen, GFP_KERNEL);
918 if (!key)
919 goto error;
920
921 p = key;
922 rta = (void *)p;
923 rta->rta_type = CRYPTO_AUTHENC_KEYA_PARAM;
924 rta->rta_len = RTA_LENGTH(sizeof(*param));
925 param = RTA_DATA(rta);
926 p += RTA_SPACE(sizeof(*param));
927
928 if (x->aalg) {
929 struct xfrm_algo_desc *aalg_desc;
930
931 memcpy(p, x->aalg->alg_key, (x->aalg->alg_key_len + 7) / 8);
932 p += (x->aalg->alg_key_len + 7) / 8;
933
934 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
935 BUG_ON(!aalg_desc);
936
937 err = -EINVAL;
938 if (aalg_desc->uinfo.auth.icv_fullbits / 8 !=
939 crypto_aead_authsize(aead)) {
940 pr_info("ESP: %s digestsize %u != %hu\n",
941 x->aalg->alg_name,
942 crypto_aead_authsize(aead),
943 aalg_desc->uinfo.auth.icv_fullbits / 8);
944 goto free_key;
945 }
946
947 err = crypto_aead_setauthsize(
948 aead, x->aalg->alg_trunc_len / 8);
949 if (err)
950 goto free_key;
951 }
952
953 param->enckeylen = cpu_to_be32((x->ealg->alg_key_len + 7) / 8);
954 memcpy(p, x->ealg->alg_key, (x->ealg->alg_key_len + 7) / 8);
955
956 err = crypto_aead_setkey(aead, key, keylen);
957
958 free_key:
959 kfree(key);
960
961 error:
962 return err;
963 }
964
esp_init_state(struct xfrm_state * x)965 static int esp_init_state(struct xfrm_state *x)
966 {
967 struct crypto_aead *aead;
968 u32 align;
969 int err;
970
971 x->data = NULL;
972
973 if (x->aead)
974 err = esp_init_aead(x);
975 else
976 err = esp_init_authenc(x);
977
978 if (err)
979 goto error;
980
981 aead = x->data;
982
983 x->props.header_len = sizeof(struct ip_esp_hdr) +
984 crypto_aead_ivsize(aead);
985 if (x->props.mode == XFRM_MODE_TUNNEL)
986 x->props.header_len += sizeof(struct iphdr);
987 else if (x->props.mode == XFRM_MODE_BEET && x->sel.family != AF_INET6)
988 x->props.header_len += IPV4_BEET_PHMAXLEN;
989 if (x->encap) {
990 struct xfrm_encap_tmpl *encap = x->encap;
991
992 switch (encap->encap_type) {
993 default:
994 err = -EINVAL;
995 goto error;
996 case UDP_ENCAP_ESPINUDP:
997 x->props.header_len += sizeof(struct udphdr);
998 break;
999 case UDP_ENCAP_ESPINUDP_NON_IKE:
1000 x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32);
1001 break;
1002 }
1003 }
1004
1005 align = ALIGN(crypto_aead_blocksize(aead), 4);
1006 x->props.trailer_len = align + 1 + crypto_aead_authsize(aead);
1007
1008 error:
1009 return err;
1010 }
1011
esp4_rcv_cb(struct sk_buff * skb,int err)1012 static int esp4_rcv_cb(struct sk_buff *skb, int err)
1013 {
1014 return 0;
1015 }
1016
1017 static const struct xfrm_type esp_type =
1018 {
1019 .description = "ESP4",
1020 .owner = THIS_MODULE,
1021 .proto = IPPROTO_ESP,
1022 .flags = XFRM_TYPE_REPLAY_PROT,
1023 .init_state = esp_init_state,
1024 .destructor = esp_destroy,
1025 .get_mtu = esp4_get_mtu,
1026 .input = esp_input,
1027 .output = esp_output,
1028 };
1029
1030 static struct xfrm4_protocol esp4_protocol = {
1031 .handler = xfrm4_rcv,
1032 .input_handler = xfrm_input,
1033 .cb_handler = esp4_rcv_cb,
1034 .err_handler = esp4_err,
1035 .priority = 0,
1036 };
1037
esp4_init(void)1038 static int __init esp4_init(void)
1039 {
1040 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
1041 pr_info("%s: can't add xfrm type\n", __func__);
1042 return -EAGAIN;
1043 }
1044 if (xfrm4_protocol_register(&esp4_protocol, IPPROTO_ESP) < 0) {
1045 pr_info("%s: can't add protocol\n", __func__);
1046 xfrm_unregister_type(&esp_type, AF_INET);
1047 return -EAGAIN;
1048 }
1049 return 0;
1050 }
1051
esp4_fini(void)1052 static void __exit esp4_fini(void)
1053 {
1054 if (xfrm4_protocol_deregister(&esp4_protocol, IPPROTO_ESP) < 0)
1055 pr_info("%s: can't remove protocol\n", __func__);
1056 if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
1057 pr_info("%s: can't remove xfrm type\n", __func__);
1058 }
1059
1060 module_init(esp4_init);
1061 module_exit(esp4_fini);
1062 MODULE_LICENSE("GPL");
1063 MODULE_ALIAS_XFRM_TYPE(AF_INET, XFRM_PROTO_ESP);
1064
