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[SCTP]: Follow Add-IP security consideratiosn wrt INIT/INIT-ACK
[linux-2.6/kmemtrace.git] / net / ipv6 / esp6.c
blob5bd5292ad9fa9021cf31899355db8cd60857a165
1 /*
2 * Copyright (C)2002 USAGI/WIDE Project
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 *
18 * Authors
19 *
20 * Mitsuru KANDA @USAGI : IPv6 Support
21 * Kazunori MIYAZAWA @USAGI :
22 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
23 *
24 * This file is derived from net/ipv4/esp.c
25 */
26
27 #include <linux/err.h>
28 #include <linux/module.h>
29 #include <net/ip.h>
30 #include <net/xfrm.h>
31 #include <net/esp.h>
32 #include <linux/scatterlist.h>
33 #include <linux/crypto.h>
34 #include <linux/kernel.h>
35 #include <linux/pfkeyv2.h>
36 #include <linux/random.h>
37 #include <linux/spinlock.h>
38 #include <net/icmp.h>
39 #include <net/ipv6.h>
40 #include <net/protocol.h>
41 #include <linux/icmpv6.h>
42
43 static int esp6_output(struct xfrm_state *x, struct sk_buff *skb)
44 {
45 int err;
46 struct ip_esp_hdr *esph;
47 struct crypto_blkcipher *tfm;
48 struct blkcipher_desc desc;
49 struct sk_buff *trailer;
50 int blksize;
51 int clen;
52 int alen;
53 int nfrags;
54 u8 *tail;
55 struct esp_data *esp = x->data;
56
57 /* skb is pure payload to encrypt */
58 err = -ENOMEM;
59
60 /* Round to block size */
61 clen = skb->len;
62
63 alen = esp->auth.icv_trunc_len;
64 tfm = esp->conf.tfm;
65 desc.tfm = tfm;
66 desc.flags = 0;
67 blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
68 clen = ALIGN(clen + 2, blksize);
69 if (esp->conf.padlen)
70 clen = ALIGN(clen, esp->conf.padlen);
71
72 if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) {
73 goto error;
74 }
75
76 /* Fill padding... */
77 tail = skb_tail_pointer(trailer);
78 do {
79 int i;
80 for (i=0; i<clen-skb->len - 2; i++)
81 tail[i] = i + 1;
82 } while (0);
83 tail[clen-skb->len - 2] = (clen - skb->len) - 2;
84 pskb_put(skb, trailer, clen - skb->len);
85
86 skb_push(skb, -skb_network_offset(skb));
87 esph = ip_esp_hdr(skb);
88 *(skb_tail_pointer(trailer) - 1) = *skb_mac_header(skb);
89 *skb_mac_header(skb) = IPPROTO_ESP;
90
91 esph->spi = x->id.spi;
92 esph->seq_no = htonl(XFRM_SKB_CB(skb)->seq);
93
94 spin_lock_bh(&x->lock);
95
96 if (esp->conf.ivlen) {
97 if (unlikely(!esp->conf.ivinitted)) {
98 get_random_bytes(esp->conf.ivec, esp->conf.ivlen);
99 esp->conf.ivinitted = 1;
100 }
101 crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
102 }
103
104 do {
105 struct scatterlist *sg = &esp->sgbuf[0];
106
107 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
108 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
109 if (!sg)
110 goto unlock;
111 }
112 sg_init_table(sg, nfrags);
113 skb_to_sgvec(skb, sg,
114 esph->enc_data +
115 esp->conf.ivlen -
116 skb->data, clen);
117 err = crypto_blkcipher_encrypt(&desc, sg, sg, clen);
118 if (unlikely(sg != &esp->sgbuf[0]))
119 kfree(sg);
120 } while (0);
121
122 if (unlikely(err))
123 goto unlock;
124
125 if (esp->conf.ivlen) {
126 memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen);
127 crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen);
128 }
129
130 if (esp->auth.icv_full_len) {
131 err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data,
132 sizeof(*esph) + esp->conf.ivlen + clen);
133 memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen);
134 }
135
136 unlock:
137 spin_unlock_bh(&x->lock);
138
139 error:
140 return err;
141 }
142
143 static int esp6_input(struct xfrm_state *x, struct sk_buff *skb)
144 {
145 struct ipv6hdr *iph;
146 struct ip_esp_hdr *esph;
147 struct esp_data *esp = x->data;
148 struct crypto_blkcipher *tfm = esp->conf.tfm;
149 struct blkcipher_desc desc = { .tfm = tfm };
150 struct sk_buff *trailer;
151 int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4);
152 int alen = esp->auth.icv_trunc_len;
153 int elen = skb->len - sizeof(*esph) - esp->conf.ivlen - alen;
154 int hdr_len = skb_network_header_len(skb);
155 int nfrags;
156 int ret = 0;
157
158 if (!pskb_may_pull(skb, sizeof(*esph))) {
159 ret = -EINVAL;
160 goto out;
161 }
162
163 if (elen <= 0 || (elen & (blksize-1))) {
164 ret = -EINVAL;
165 goto out;
166 }
167
168 if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) {
169 ret = -EINVAL;
170 goto out;
171 }
172
173 skb->ip_summed = CHECKSUM_NONE;
174
175 spin_lock(&x->lock);
176
177 /* If integrity check is required, do this. */
178 if (esp->auth.icv_full_len) {
179 u8 sum[alen];
180
181 ret = esp_mac_digest(esp, skb, 0, skb->len - alen);
182 if (ret)
183 goto unlock;
184
185 if (skb_copy_bits(skb, skb->len - alen, sum, alen))
186 BUG();
187
188 if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) {
189 ret = -EBADMSG;
190 goto unlock;
191 }
192 }
193
194 esph = (struct ip_esp_hdr *)skb->data;
195 iph = ipv6_hdr(skb);
196
197 /* Get ivec. This can be wrong, check against another impls. */
198 if (esp->conf.ivlen)
199 crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen);
200
201 {
202 struct scatterlist *sg = &esp->sgbuf[0];
203
204 if (unlikely(nfrags > ESP_NUM_FAST_SG)) {
205 sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC);
206 if (!sg) {
207 ret = -ENOMEM;
208 goto unlock;
209 }
210 }
211 sg_init_table(sg, nfrags);
212 skb_to_sgvec(skb, sg,
213 sizeof(*esph) + esp->conf.ivlen,
214 elen);
215 ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen);
216 if (unlikely(sg != &esp->sgbuf[0]))
217 kfree(sg);
218 }
219
220 unlock:
221 spin_unlock(&x->lock);
222
223 if (unlikely(ret))
224 goto out;
225
226 {
227 u8 nexthdr[2];
228 u8 padlen;
229
230 if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2))
231 BUG();
232
233 padlen = nexthdr[0];
234 if (padlen+2 >= elen) {
235 LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen);
236 ret = -EINVAL;
237 goto out;
238 }
239 /* ... check padding bits here. Silly. :-) */
240
241 /* RFC4303: Drop dummy packets without any error */
242 if (nexthdr[1] == IPPROTO_NONE) {
243 ret = -EINVAL;
244 goto out;
245 }
246
247 pskb_trim(skb, skb->len - alen - padlen - 2);
248 ret = nexthdr[1];
249 }
250
251 __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen);
252 skb_set_transport_header(skb, -hdr_len);
253 out:
254 return ret;
255 }
256
257 static u32 esp6_get_mtu(struct xfrm_state *x, int mtu)
258 {
259 struct esp_data *esp = x->data;
260 u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4);
261 u32 align = max_t(u32, blksize, esp->conf.padlen);
262 u32 rem;
263
264 mtu -= x->props.header_len + esp->auth.icv_trunc_len;
265 rem = mtu & (align - 1);
266 mtu &= ~(align - 1);
267
268 if (x->props.mode != XFRM_MODE_TUNNEL) {
269 u32 padsize = ((blksize - 1) & 7) + 1;
270 mtu -= blksize - padsize;
271 mtu += min_t(u32, blksize - padsize, rem);
272 }
273
274 return mtu - 2;
275 }
276
277 static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
278 int type, int code, int offset, __be32 info)
279 {
280 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
281 struct ip_esp_hdr *esph = (struct ip_esp_hdr *)(skb->data + offset);
282 struct xfrm_state *x;
283
284 if (type != ICMPV6_DEST_UNREACH &&
285 type != ICMPV6_PKT_TOOBIG)
286 return;
287
288 x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6);
289 if (!x)
290 return;
291 printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n",
292 ntohl(esph->spi), NIP6(iph->daddr));
293 xfrm_state_put(x);
294 }
295
296 static void esp6_destroy(struct xfrm_state *x)
297 {
298 struct esp_data *esp = x->data;
299
300 if (!esp)
301 return;
302
303 crypto_free_blkcipher(esp->conf.tfm);
304 esp->conf.tfm = NULL;
305 kfree(esp->conf.ivec);
306 esp->conf.ivec = NULL;
307 crypto_free_hash(esp->auth.tfm);
308 esp->auth.tfm = NULL;
309 kfree(esp->auth.work_icv);
310 esp->auth.work_icv = NULL;
311 kfree(esp);
312 }
313
314 static int esp6_init_state(struct xfrm_state *x)
315 {
316 struct esp_data *esp = NULL;
317 struct crypto_blkcipher *tfm;
318
319 if (x->ealg == NULL)
320 goto error;
321
322 if (x->encap)
323 goto error;
324
325 esp = kzalloc(sizeof(*esp), GFP_KERNEL);
326 if (esp == NULL)
327 return -ENOMEM;
328
329 if (x->aalg) {
330 struct xfrm_algo_desc *aalg_desc;
331 struct crypto_hash *hash;
332
333 hash = crypto_alloc_hash(x->aalg->alg_name, 0,
334 CRYPTO_ALG_ASYNC);
335 if (IS_ERR(hash))
336 goto error;
337
338 esp->auth.tfm = hash;
339 if (crypto_hash_setkey(hash, x->aalg->alg_key,
340 (x->aalg->alg_key_len + 7) / 8))
341 goto error;
342
343 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
344 BUG_ON(!aalg_desc);
345
346 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
347 crypto_hash_digestsize(hash)) {
348 NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n",
349 x->aalg->alg_name,
350 crypto_hash_digestsize(hash),
351 aalg_desc->uinfo.auth.icv_fullbits/8);
352 goto error;
353 }
354
355 esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
356 esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8;
357
358 esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL);
359 if (!esp->auth.work_icv)
360 goto error;
361 }
362 tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC);
363 if (IS_ERR(tfm))
364 goto error;
365 esp->conf.tfm = tfm;
366 esp->conf.ivlen = crypto_blkcipher_ivsize(tfm);
367 esp->conf.padlen = 0;
368 if (esp->conf.ivlen) {
369 esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL);
370 if (unlikely(esp->conf.ivec == NULL))
371 goto error;
372 esp->conf.ivinitted = 0;
373 }
374 if (crypto_blkcipher_setkey(tfm, x->ealg->alg_key,
375 (x->ealg->alg_key_len + 7) / 8))
376 goto error;
377 x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen;
378 switch (x->props.mode) {
379 case XFRM_MODE_BEET:
380 case XFRM_MODE_TRANSPORT:
381 break;
382 case XFRM_MODE_TUNNEL:
383 x->props.header_len += sizeof(struct ipv6hdr);
384 break;
385 default:
386 goto error;
387 }
388 x->data = esp;
389 return 0;
390
391 error:
392 x->data = esp;
393 esp6_destroy(x);
394 x->data = NULL;
395 return -EINVAL;
396 }
397
398 static struct xfrm_type esp6_type =
399 {
400 .description = "ESP6",
401 .owner = THIS_MODULE,
402 .proto = IPPROTO_ESP,
403 .flags = XFRM_TYPE_REPLAY_PROT,
404 .init_state = esp6_init_state,
405 .destructor = esp6_destroy,
406 .get_mtu = esp6_get_mtu,
407 .input = esp6_input,
408 .output = esp6_output,
409 .hdr_offset = xfrm6_find_1stfragopt,
410 };
411
412 static struct inet6_protocol esp6_protocol = {
413 .handler = xfrm6_rcv,
414 .err_handler = esp6_err,
415 .flags = INET6_PROTO_NOPOLICY,
416 };
417
418 static int __init esp6_init(void)
419 {
420 if (xfrm_register_type(&esp6_type, AF_INET6) < 0) {
421 printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n");
422 return -EAGAIN;
423 }
424 if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) {
425 printk(KERN_INFO "ipv6 esp init: can't add protocol\n");
426 xfrm_unregister_type(&esp6_type, AF_INET6);
427 return -EAGAIN;
428 }
429
430 return 0;
431 }
432
433 static void __exit esp6_fini(void)
434 {
435 if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0)
436 printk(KERN_INFO "ipv6 esp close: can't remove protocol\n");
437 if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0)
438 printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n");
439 }
440
441 module_init(esp6_init);
442 module_exit(esp6_fini);
443
444 MODULE_LICENSE("GPL");
445 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_ESP);
kmemtrace - Kernel memory tracer