1#include <linux/config.h>
2#include <linux/module.h>
3#include <net/inet_ecn.h>
4#include <net/ip.h>
5#include <net/xfrm.h>
6#include <net/esp.h>
7#include <asm/scatterlist.h>
8#include <linux/crypto.h>
9#include <linux/pfkeyv2.h>
10#include <linux/random.h>
11#include <net/icmp.h>
12#include <net/udp.h>
13
14#define MAX_SG_ONSTACK 4
15
16
17struct esp_decap_data {
18 xfrm_address_t saddr;
19 __u16 sport;
20 __u8 proto;
21};
22
23int esp_output(struct sk_buff *skb)
24{
25 int err;
26 struct dst_entry *dst = skb->dst;
27 struct xfrm_state *x = dst->xfrm;
28 struct iphdr *iph, *top_iph;
29 struct ip_esp_hdr *esph;
30 struct crypto_tfm *tfm;
31 struct esp_data *esp;
32 struct sk_buff *trailer;
33 struct udphdr *uh = NULL;
34 struct xfrm_encap_tmpl *encap = NULL;
35 int blksize;
36 int clen;
37 int alen;
38 int nfrags;
39 union {
40 struct iphdr iph;
41 char buf[60];
42 } tmp_iph;
43
44
45 if (skb->ip_summed == CHECKSUM_HW && skb_checksum_help(skb) == NULL) {
46 err = -EINVAL;
47 goto error_nolock;
48 }
49
50 spin_lock_bh(&x->lock);
51 err = xfrm_check_output(x, skb, AF_INET);
52 if (err)
53 goto error;
54 err = -ENOMEM;
55
56
57 if (!x->props.mode) {
58 iph = skb->nh.iph;
59 memcpy(&tmp_iph, iph, iph->ihl*4);
60 __skb_pull(skb, iph->ihl*4);
61 }
62
63
64
65 clen = skb->len;
66
67 esp = x->data;
68 alen = esp->auth.icv_trunc_len;
69 tfm = esp->conf.tfm;
70 blksize = (crypto_tfm_alg_blocksize(tfm) + 3) & ~3;
71 clen = (clen + 2 + blksize-1)&~(blksize-1);
72 if (esp->conf.padlen)
73 clen = (clen + esp->conf.padlen-1)&~(esp->conf.padlen-1);
74
75 if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0)
76 goto error;
77
78
79 do {
80 int i;
81 for (i=0; i<clen-skb->len - 2; i++)
82 *(u8*)(trailer->tail + i) = i+1;
83 } while (0);
84 *(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2;
85 pskb_put(skb, trailer, clen - skb->len);
86
87 encap = x->encap;
88
89 iph = skb->nh.iph;
90 if (x->props.mode) {
91 top_iph = (struct iphdr*)skb_push(skb, x->props.header_len);
92 esph = (struct ip_esp_hdr*)(top_iph+1);
93 if (encap && encap->encap_type) {
94 switch (encap->encap_type) {
95 case UDP_ENCAP_ESPINUDP:
96 uh = (struct udphdr*) esph;
97 esph = (struct ip_esp_hdr*)(uh+1);
98 top_iph->protocol = IPPROTO_UDP;
99 break;
100 default:
101 printk(KERN_INFO
102 "esp_output(): Unhandled encap: %u\n",
103 encap->encap_type);
104 top_iph->protocol = IPPROTO_ESP;
105 break;
106 }
107 } else
108 top_iph->protocol = IPPROTO_ESP;
109 *(u8*)(trailer->tail - 1) = IPPROTO_IPIP;
110 top_iph->ihl = 5;
111 top_iph->version = 4;
112 top_iph->tos = iph->tos;
113 if (x->props.flags & XFRM_STATE_NOECN)
114 IP_ECN_clear(top_iph);
115 top_iph->tot_len = htons(skb->len + alen);
116 top_iph->frag_off = iph->frag_off&htons(IP_DF);
117 if (!(top_iph->frag_off))
118 ip_select_ident(top_iph, dst, 0);
119 top_iph->ttl = iph->ttl;
120 top_iph->check = 0;
121 top_iph->saddr = x->props.saddr.a4;
122 top_iph->daddr = x->id.daddr.a4;
123 memset(&(IPCB(skb)->opt), 0, sizeof(struct ip_options));
124 } else {
125 esph = (struct ip_esp_hdr*)skb_push(skb, x->props.header_len);
126 top_iph = (struct iphdr*)skb_push(skb, iph->ihl*4);
127 memcpy(top_iph, &tmp_iph, iph->ihl*4);
128 if (encap && encap->encap_type) {
129 switch (encap->encap_type) {
130 case UDP_ENCAP_ESPINUDP:
131 uh = (struct udphdr*) esph;
132 esph = (struct ip_esp_hdr*)(uh+1);
133 top_iph->protocol = IPPROTO_UDP;
134 break;
135 default:
136 printk(KERN_INFO
137 "esp_output(): Unhandled encap: %u\n",
138 encap->encap_type);
139 top_iph->protocol = IPPROTO_ESP;
140 break;
141 }
142 } else
143 top_iph->protocol = IPPROTO_ESP;
144 iph = &tmp_iph.iph;
145 top_iph->tot_len = htons(skb->len + alen);
146 top_iph->check = 0;
147 top_iph->frag_off = iph->frag_off;
148 *(u8*)(trailer->tail - 1) = iph->protocol;
149 }
150
151
152 if (encap && uh) {
153 uh->source = encap->encap_sport;
154 uh->dest = encap->encap_dport;
155 uh->len = htons(skb->len + alen - sizeof(struct iphdr));
156 uh->check = 0;
157 }
158
159 esph->spi = x->id.spi;
160 esph->seq_no = htonl(++x->replay.oseq);
161
162 if (esp->conf.ivlen)
163 crypto_cipher_set_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
164
165 do {
166 struct scatterlist sgbuf[nfrags>MAX_SG_ONSTACK ? 0 : nfrags];
167 struct scatterlist *sg = sgbuf;
168
169 if (unlikely(nfrags > MAX_SG_ONSTACK)) {
170 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
171 if (!sg)
172 goto error;
173 }
174 skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen);
175 crypto_cipher_encrypt(tfm, sg, sg, clen);
176 if (unlikely(sg != sgbuf))
177 kfree(sg);
178 } while (0);
179
180 if (esp->conf.ivlen) {
181 memcpy(esph->enc_data, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
182 crypto_cipher_get_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm));
183 }
184
185 if (esp->auth.icv_full_len) {
186 esp->auth.icv(esp, skb, (u8*)esph-skb->data,
187 sizeof(struct ip_esp_hdr) + esp->conf.ivlen+clen, trailer->tail);
188 pskb_put(skb, trailer, alen);
189 }
190
191 ip_send_check(top_iph);
192
193 skb->nh.raw = skb->data;
194
195 x->curlft.bytes += skb->len;
196 x->curlft.packets++;
197 spin_unlock_bh(&x->lock);
198 if ((skb->dst = dst_pop(dst)) == NULL) {
199 err = -EHOSTUNREACH;
200 goto error_nolock;
201 }
202 return NET_XMIT_BYPASS;
203
204error:
205 spin_unlock_bh(&x->lock);
206error_nolock:
207 kfree_skb(skb);
208 return err;
209}
210
211
212
213
214
215
216int esp_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
217{
218 struct iphdr *iph;
219 struct ip_esp_hdr *esph;
220 struct esp_data *esp = x->data;
221 struct sk_buff *trailer;
222 int blksize = crypto_tfm_alg_blocksize(esp->conf.tfm);
223 int alen = esp->auth.icv_trunc_len;
224 int elen = skb->len - sizeof(struct ip_esp_hdr) - esp->conf.ivlen - alen;
225 int nfrags;
226 int encap_len = 0;
227
228 if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr)))
229 goto out;
230
231 if (elen <= 0 || (elen & (blksize-1)))
232 goto out;
233
234
235 if (esp->auth.icv_full_len) {
236 u8 sum[esp->auth.icv_full_len];
237 u8 sum1[alen];
238
239 esp->auth.icv(esp, skb, 0, skb->len-alen, sum);
240
241 if (skb_copy_bits(skb, skb->len-alen, sum1, alen))
242 BUG();
243
244 if (unlikely(memcmp(sum, sum1, alen))) {
245 x->stats.integrity_failed++;
246 goto out;
247 }
248 }
249
250 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0)
251 goto out;
252
253 skb->ip_summed = CHECKSUM_NONE;
254
255 esph = (struct ip_esp_hdr*)skb->data;
256 iph = skb->nh.iph;
257
258
259 if (esp->conf.ivlen)
260 crypto_cipher_set_iv(esp->conf.tfm, esph->enc_data, crypto_tfm_alg_ivsize(esp->conf.tfm));
261
262 {
263 u8 nexthdr[2];
264 struct scatterlist sgbuf[nfrags>MAX_SG_ONSTACK ? 0 : nfrags];
265 struct scatterlist *sg = sgbuf;
266 u8 workbuf[60];
267 int padlen;
268
269 if (unlikely(nfrags > MAX_SG_ONSTACK)) {
270 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
271 if (!sg)
272 goto out;
273 }
274 skb_to_sgvec(skb, sg, sizeof(struct ip_esp_hdr) + esp->conf.ivlen, elen);
275 crypto_cipher_decrypt(esp->conf.tfm, sg, sg, elen);
276 if (unlikely(sg != sgbuf))
277 kfree(sg);
278
279 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
280 BUG();
281
282 padlen = nexthdr[0];
283 if (padlen+2 >= elen)
284 goto out;
285
286
287
288 if (x->encap && decap && decap->decap_type) {
289 struct esp_decap_data *encap_data;
290 struct udphdr *uh = (struct udphdr *) (iph+1);
291
292 encap_data = (struct esp_decap_data *) (decap->decap_data);
293 encap_data->proto = 0;
294
295 switch (decap->decap_type) {
296 case UDP_ENCAP_ESPINUDP:
297
298 if ((void*)uh == (void*)esph) {
299 printk(KERN_DEBUG
300 "esp_input(): Got ESP; expecting ESPinUDP\n");
301 break;
302 }
303
304 encap_data->proto = AF_INET;
305 encap_data->saddr.a4 = iph->saddr;
306 encap_data->sport = uh->source;
307 encap_len = (void*)esph - (void*)uh;
308 if (encap_len != sizeof(*uh))
309 printk(KERN_DEBUG
310 "esp_input(): UDP -> ESP: too much room: %d\n",
311 encap_len);
312 break;
313
314 default:
315 printk(KERN_INFO
316 "esp_input(): processing unknown encap type: %u\n",
317 decap->decap_type);
318 break;
319 }
320 }
321
322 iph->protocol = nexthdr[1];
323 pskb_trim(skb, skb->len - alen - padlen - 2);
324 memcpy(workbuf, skb->nh.raw, iph->ihl*4);
325 skb->h.raw = skb_pull(skb, sizeof(struct ip_esp_hdr) + esp->conf.ivlen);
326 skb->nh.raw += encap_len + sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
327 memcpy(skb->nh.raw, workbuf, iph->ihl*4);
328 skb->nh.iph->tot_len = htons(skb->len);
329 }
330
331 return 0;
332
333out:
334 return -EINVAL;
335}
336
337int esp_post_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb)
338{
339
340 if (x->encap) {
341 struct xfrm_encap_tmpl *encap;
342 struct esp_decap_data *decap_data;
343
344 encap = x->encap;
345 decap_data = (struct esp_decap_data *)(decap->decap_data);
346
347
348 if (encap->encap_type != decap->decap_type)
349 return -EINVAL;
350
351
352 if (!encap->encap_type)
353 return 0;
354
355 switch (encap->encap_type) {
356 case UDP_ENCAP_ESPINUDP:
357
358
359
360
361
362
363 if (decap_data->proto == AF_INET &&
364 (decap_data->saddr.a4 != x->props.saddr.a4 ||
365 decap_data->sport != encap->encap_sport)) {
366 xfrm_address_t ipaddr;
367
368 ipaddr.a4 = decap_data->saddr.a4;
369 km_new_mapping(x, &ipaddr, decap_data->sport);
370
371
372
373
374
375
376
377
378 }
379
380
381
382
383
384
385
386
387 if (!x->props.mode)
388 skb->ip_summed = CHECKSUM_UNNECESSARY;
389
390 break;
391 default:
392 printk(KERN_INFO
393 "esp4_post_input(): Unhandled encap type: %u\n",
394 encap->encap_type);
395 break;
396 }
397 }
398 return 0;
399}
400
401static u32 esp4_get_max_size(struct xfrm_state *x, int mtu)
402{
403 struct esp_data *esp = x->data;
404 u32 blksize = crypto_tfm_alg_blocksize(esp->conf.tfm);
405
406 if (x->props.mode) {
407 mtu = (mtu + 2 + blksize-1)&~(blksize-1);
408 } else {
409
410 mtu += 2 + blksize;
411 }
412 if (esp->conf.padlen)
413 mtu = (mtu + esp->conf.padlen-1)&~(esp->conf.padlen-1);
414
415 return mtu + x->props.header_len + esp->auth.icv_trunc_len;
416}
417
418void esp4_err(struct sk_buff *skb, u32 info)
419{
420 struct iphdr *iph = (struct iphdr*)skb->data;
421 struct ip_esp_hdr *esph = (struct ip_esp_hdr*)(skb->data+(iph->ihl<<2));
422 struct xfrm_state *x;
423
424 if (skb->h.icmph->type != ICMP_DEST_UNREACH ||
425 skb->h.icmph->code != ICMP_FRAG_NEEDED)
426 return;
427
428 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET);
429 if (!x)
430 return;
431 printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n",
432 ntohl(esph->spi), ntohl(iph->daddr));
433 xfrm_state_put(x);
434}
435
436void esp_destroy(struct xfrm_state *x)
437{
438 struct esp_data *esp = x->data;
439
440 if (!esp)
441 return;
442
443 if (esp->conf.tfm) {
444 crypto_free_tfm(esp->conf.tfm);
445 esp->conf.tfm = NULL;
446 }
447 if (esp->conf.ivec) {
448 kfree(esp->conf.ivec);
449 esp->conf.ivec = NULL;
450 }
451 if (esp->auth.tfm) {
452 crypto_free_tfm(esp->auth.tfm);
453 esp->auth.tfm = NULL;
454 }
455 if (esp->auth.work_icv) {
456 kfree(esp->auth.work_icv);
457 esp->auth.work_icv = NULL;
458 }
459 kfree(esp);
460}
461
462int esp_init_state(struct xfrm_state *x, void *args)
463{
464 struct esp_data *esp = NULL;
465
466
467 if (x->aalg) {
468 if (x->aalg->alg_key_len > 512)
469 goto error;
470 }
471 if (x->ealg == NULL)
472 goto error;
473
474 esp = kmalloc(sizeof(*esp), GFP_KERNEL);
475 if (esp == NULL)
476 return -ENOMEM;
477
478 memset(esp, 0, sizeof(*esp));
479
480 if (x->aalg) {
481 struct xfrm_algo_desc *aalg_desc;
482
483 esp->auth.key = x->aalg->alg_key;
484 esp->auth.key_len = (x->aalg->alg_key_len+7)/8;
485 esp->auth.tfm = crypto_alloc_tfm(x->aalg->alg_name, 0);
486 if (esp->auth.tfm == NULL)
487 goto error;
488 esp->auth.icv = esp_hmac_digest;
489
490 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name);
491 BUG_ON(!aalg_desc);
492
493 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
494 crypto_tfm_alg_digestsize(esp->auth.tfm)) {
495 printk(KERN_INFO "ESP: %s digestsize %u != %hu\n",
496 x->aalg->alg_name,
497 crypto_tfm_alg_digestsize(esp->auth.tfm),
498 aalg_desc->uinfo.auth.icv_fullbits/8);
499 goto error;
500 }
501
502 esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
503 esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
504
505 esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
506 if (!esp->auth.work_icv)
507 goto error;
508 }
509 esp->conf.key = x->ealg->alg_key;
510 esp->conf.key_len = (x->ealg->alg_key_len+7)/8;
511 if (x->props.ealgo == SADB_EALG_NULL)
512 esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_ECB);
513 else
514 esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_CBC);
515 if (esp->conf.tfm == NULL)
516 goto error;
517 esp->conf.ivlen = crypto_tfm_alg_ivsize(esp->conf.tfm);
518 esp->conf.padlen = 0;
519 if (esp->conf.ivlen) {
520 esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
521 get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
522 }
523 crypto_cipher_setkey(esp->conf.tfm, esp->conf.key, esp->conf.key_len);
524 x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
525 if (x->props.mode)
526 x->props.header_len += sizeof(struct iphdr);
527 if (x->encap) {
528 struct xfrm_encap_tmpl *encap = x->encap;
529
530 if (encap->encap_type) {
531 switch (encap->encap_type) {
532 case UDP_ENCAP_ESPINUDP:
533 x->props.header_len += sizeof(struct udphdr);
534 break;
535 default:
536 printk (KERN_INFO
537 "esp_init_state(): Unhandled encap type: %u\n",
538 encap->encap_type);
539 break;
540 }
541 }
542 }
543 x->data = esp;
544 x->props.trailer_len = esp4_get_max_size(x, 0) - x->props.header_len;
545 return 0;
546
547error:
548 if (esp) {
549 if (esp->auth.tfm)
550 crypto_free_tfm(esp->auth.tfm);
551 if (esp->auth.work_icv)
552 kfree(esp->auth.work_icv);
553 if (esp->conf.tfm)
554 crypto_free_tfm(esp->conf.tfm);
555 kfree(esp);
556 }
557 return -EINVAL;
558}
559
560static struct xfrm_type esp_type =
561{
562 .description = "ESP4",
563 .owner = THIS_MODULE,
564 .proto = IPPROTO_ESP,
565 .init_state = esp_init_state,
566 .destructor = esp_destroy,
567 .get_max_size = esp4_get_max_size,
568 .input = esp_input,
569 .post_input = esp_post_input,
570 .output = esp_output
571};
572
573static struct inet_protocol esp4_protocol = {
574 .handler = xfrm4_rcv,
575 .err_handler = esp4_err,
576 .no_policy = 1,
577};
578
579static int __init esp4_init(void)
580{
581 struct xfrm_decap_state decap;
582
583 if (sizeof(struct esp_decap_data) <
584 sizeof(decap.decap_data)) {
585 extern void decap_data_too_small(void);
586
587 decap_data_too_small();
588 }
589
590 if (xfrm_register_type(&esp_type, AF_INET) < 0) {
591 printk(KERN_INFO "ip esp init: can't add xfrm type\n");
592 return -EAGAIN;
593 }
594 if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) {
595 printk(KERN_INFO "ip esp init: can't add protocol\n");
596 xfrm_unregister_type(&esp_type, AF_INET);
597 return -EAGAIN;
598 }
599 return 0;
600}
601
602static void __exit esp4_fini(void)
603{
604 if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0)
605 printk(KERN_INFO "ip esp close: can't remove protocol\n");
606 if (xfrm_unregister_type(&esp_type, AF_INET) < 0)
607 printk(KERN_INFO "ip esp close: can't remove xfrm type\n");
608}
609
610module_init(esp4_init);
611module_exit(esp4_fini);
612MODULE_LICENSE("GPL");
613
