Commit | Line | Data |
---|---|---|
1da177e4 LT |
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/config.h> | |
28 | #include <linux/module.h> | |
29 | #include <net/ip.h> | |
30 | #include <net/xfrm.h> | |
31 | #include <net/esp.h> | |
32 | #include <asm/scatterlist.h> | |
33 | #include <linux/crypto.h> | |
34 | #include <linux/pfkeyv2.h> | |
35 | #include <linux/random.h> | |
36 | #include <net/icmp.h> | |
37 | #include <net/ipv6.h> | |
38 | #include <linux/icmpv6.h> | |
39 | ||
40 | static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) | |
41 | { | |
42 | int err; | |
43 | int hdr_len; | |
44 | struct ipv6hdr *top_iph; | |
45 | struct ipv6_esp_hdr *esph; | |
46 | struct crypto_tfm *tfm; | |
47 | struct esp_data *esp; | |
48 | struct sk_buff *trailer; | |
49 | int blksize; | |
50 | int clen; | |
51 | int alen; | |
52 | int nfrags; | |
53 | ||
54 | esp = x->data; | |
55 | hdr_len = skb->h.raw - skb->data + | |
56 | sizeof(*esph) + esp->conf.ivlen; | |
57 | ||
58 | /* Strip IP+ESP header. */ | |
59 | __skb_pull(skb, hdr_len); | |
60 | ||
61 | /* Now skb is pure payload to encrypt */ | |
62 | err = -ENOMEM; | |
63 | ||
64 | /* Round to block size */ | |
65 | clen = skb->len; | |
66 | ||
67 | alen = esp->auth.icv_trunc_len; | |
68 | tfm = esp->conf.tfm; | |
69 | blksize = (crypto_tfm_alg_blocksize(tfm) + 3) & ~3; | |
70 | clen = (clen + 2 + blksize-1)&~(blksize-1); | |
71 | if (esp->conf.padlen) | |
72 | clen = (clen + esp->conf.padlen-1)&~(esp->conf.padlen-1); | |
73 | ||
74 | if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) { | |
75 | goto error; | |
76 | } | |
77 | ||
78 | /* Fill padding... */ | |
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 | top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len); | |
88 | esph = (struct ipv6_esp_hdr *)skb->h.raw; | |
89 | top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph)); | |
90 | *(u8*)(trailer->tail - 1) = *skb->nh.raw; | |
91 | *skb->nh.raw = IPPROTO_ESP; | |
92 | ||
93 | esph->spi = x->id.spi; | |
94 | esph->seq_no = htonl(++x->replay.oseq); | |
95 | ||
96 | if (esp->conf.ivlen) | |
97 | crypto_cipher_set_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm)); | |
98 | ||
99 | do { | |
100 | struct scatterlist *sg = &esp->sgbuf[0]; | |
101 | ||
102 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { | |
103 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); | |
104 | if (!sg) | |
105 | goto error; | |
106 | } | |
107 | skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen); | |
108 | crypto_cipher_encrypt(tfm, sg, sg, clen); | |
109 | if (unlikely(sg != &esp->sgbuf[0])) | |
110 | kfree(sg); | |
111 | } while (0); | |
112 | ||
113 | if (esp->conf.ivlen) { | |
114 | memcpy(esph->enc_data, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm)); | |
115 | crypto_cipher_get_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm)); | |
116 | } | |
117 | ||
118 | if (esp->auth.icv_full_len) { | |
119 | esp->auth.icv(esp, skb, (u8*)esph-skb->data, | |
120 | sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen+clen, trailer->tail); | |
121 | pskb_put(skb, trailer, alen); | |
122 | } | |
123 | ||
124 | err = 0; | |
125 | ||
126 | error: | |
127 | return err; | |
128 | } | |
129 | ||
130 | static int esp6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb) | |
131 | { | |
132 | struct ipv6hdr *iph; | |
133 | struct ipv6_esp_hdr *esph; | |
134 | struct esp_data *esp = x->data; | |
135 | struct sk_buff *trailer; | |
136 | int blksize = crypto_tfm_alg_blocksize(esp->conf.tfm); | |
137 | int alen = esp->auth.icv_trunc_len; | |
138 | int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen; | |
139 | ||
140 | int hdr_len = skb->h.raw - skb->nh.raw; | |
141 | int nfrags; | |
142 | unsigned char *tmp_hdr = NULL; | |
143 | int ret = 0; | |
144 | ||
145 | if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) { | |
146 | ret = -EINVAL; | |
147 | goto out_nofree; | |
148 | } | |
149 | ||
150 | if (elen <= 0 || (elen & (blksize-1))) { | |
151 | ret = -EINVAL; | |
152 | goto out_nofree; | |
153 | } | |
154 | ||
155 | tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC); | |
156 | if (!tmp_hdr) { | |
157 | ret = -ENOMEM; | |
158 | goto out_nofree; | |
159 | } | |
160 | memcpy(tmp_hdr, skb->nh.raw, hdr_len); | |
161 | ||
162 | /* If integrity check is required, do this. */ | |
163 | if (esp->auth.icv_full_len) { | |
164 | u8 sum[esp->auth.icv_full_len]; | |
165 | u8 sum1[alen]; | |
166 | ||
167 | esp->auth.icv(esp, skb, 0, skb->len-alen, sum); | |
168 | ||
169 | if (skb_copy_bits(skb, skb->len-alen, sum1, alen)) | |
170 | BUG(); | |
171 | ||
172 | if (unlikely(memcmp(sum, sum1, alen))) { | |
173 | x->stats.integrity_failed++; | |
174 | ret = -EINVAL; | |
175 | goto out; | |
176 | } | |
177 | } | |
178 | ||
179 | if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) { | |
180 | ret = -EINVAL; | |
181 | goto out; | |
182 | } | |
183 | ||
184 | skb->ip_summed = CHECKSUM_NONE; | |
185 | ||
186 | esph = (struct ipv6_esp_hdr*)skb->data; | |
187 | iph = skb->nh.ipv6h; | |
188 | ||
189 | /* Get ivec. This can be wrong, check against another impls. */ | |
190 | if (esp->conf.ivlen) | |
191 | crypto_cipher_set_iv(esp->conf.tfm, esph->enc_data, crypto_tfm_alg_ivsize(esp->conf.tfm)); | |
192 | ||
193 | { | |
194 | u8 nexthdr[2]; | |
195 | struct scatterlist *sg = &esp->sgbuf[0]; | |
196 | u8 padlen; | |
197 | ||
198 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { | |
199 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); | |
200 | if (!sg) { | |
201 | ret = -ENOMEM; | |
202 | goto out; | |
203 | } | |
204 | } | |
205 | skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen); | |
206 | crypto_cipher_decrypt(esp->conf.tfm, sg, sg, elen); | |
207 | if (unlikely(sg != &esp->sgbuf[0])) | |
208 | kfree(sg); | |
209 | ||
210 | if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2)) | |
211 | BUG(); | |
212 | ||
213 | padlen = nexthdr[0]; | |
214 | if (padlen+2 >= elen) { | |
215 | LIMIT_NETDEBUG( | |
216 | printk(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen)); | |
217 | ret = -EINVAL; | |
218 | goto out; | |
219 | } | |
220 | /* ... check padding bits here. Silly. :-) */ | |
221 | ||
222 | pskb_trim(skb, skb->len - alen - padlen - 2); | |
223 | skb->h.raw = skb_pull(skb, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen); | |
224 | skb->nh.raw += sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen; | |
225 | memcpy(skb->nh.raw, tmp_hdr, hdr_len); | |
226 | skb->nh.ipv6h->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); | |
227 | ret = nexthdr[1]; | |
228 | } | |
229 | ||
230 | out: | |
231 | kfree(tmp_hdr); | |
232 | out_nofree: | |
233 | return ret; | |
234 | } | |
235 | ||
236 | static u32 esp6_get_max_size(struct xfrm_state *x, int mtu) | |
237 | { | |
238 | struct esp_data *esp = x->data; | |
239 | u32 blksize = crypto_tfm_alg_blocksize(esp->conf.tfm); | |
240 | ||
241 | if (x->props.mode) { | |
242 | mtu = (mtu + 2 + blksize-1)&~(blksize-1); | |
243 | } else { | |
244 | /* The worst case. */ | |
245 | mtu += 2 + blksize; | |
246 | } | |
247 | if (esp->conf.padlen) | |
248 | mtu = (mtu + esp->conf.padlen-1)&~(esp->conf.padlen-1); | |
249 | ||
250 | return mtu + x->props.header_len + esp->auth.icv_full_len; | |
251 | } | |
252 | ||
253 | static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, | |
254 | int type, int code, int offset, __u32 info) | |
255 | { | |
256 | struct ipv6hdr *iph = (struct ipv6hdr*)skb->data; | |
257 | struct ipv6_esp_hdr *esph = (struct ipv6_esp_hdr*)(skb->data+offset); | |
258 | struct xfrm_state *x; | |
259 | ||
260 | if (type != ICMPV6_DEST_UNREACH && | |
261 | type != ICMPV6_PKT_TOOBIG) | |
262 | return; | |
263 | ||
264 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6); | |
265 | if (!x) | |
266 | return; | |
267 | printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" | |
268 | "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n", | |
269 | ntohl(esph->spi), NIP6(iph->daddr)); | |
270 | xfrm_state_put(x); | |
271 | } | |
272 | ||
273 | static void esp6_destroy(struct xfrm_state *x) | |
274 | { | |
275 | struct esp_data *esp = x->data; | |
276 | ||
277 | if (!esp) | |
278 | return; | |
279 | ||
280 | if (esp->conf.tfm) { | |
281 | crypto_free_tfm(esp->conf.tfm); | |
282 | esp->conf.tfm = NULL; | |
283 | } | |
284 | if (esp->conf.ivec) { | |
285 | kfree(esp->conf.ivec); | |
286 | esp->conf.ivec = NULL; | |
287 | } | |
288 | if (esp->auth.tfm) { | |
289 | crypto_free_tfm(esp->auth.tfm); | |
290 | esp->auth.tfm = NULL; | |
291 | } | |
292 | if (esp->auth.work_icv) { | |
293 | kfree(esp->auth.work_icv); | |
294 | esp->auth.work_icv = NULL; | |
295 | } | |
296 | kfree(esp); | |
297 | } | |
298 | ||
72cb6962 | 299 | static int esp6_init_state(struct xfrm_state *x) |
1da177e4 LT |
300 | { |
301 | struct esp_data *esp = NULL; | |
302 | ||
303 | /* null auth and encryption can have zero length keys */ | |
304 | if (x->aalg) { | |
305 | if (x->aalg->alg_key_len > 512) | |
306 | goto error; | |
307 | } | |
308 | if (x->ealg == NULL) | |
309 | goto error; | |
310 | ||
311 | if (x->encap) | |
312 | goto error; | |
313 | ||
314 | esp = kmalloc(sizeof(*esp), GFP_KERNEL); | |
315 | if (esp == NULL) | |
316 | return -ENOMEM; | |
317 | ||
318 | memset(esp, 0, sizeof(*esp)); | |
319 | ||
320 | if (x->aalg) { | |
321 | struct xfrm_algo_desc *aalg_desc; | |
322 | ||
323 | esp->auth.key = x->aalg->alg_key; | |
324 | esp->auth.key_len = (x->aalg->alg_key_len+7)/8; | |
325 | esp->auth.tfm = crypto_alloc_tfm(x->aalg->alg_name, 0); | |
326 | if (esp->auth.tfm == NULL) | |
327 | goto error; | |
328 | esp->auth.icv = esp_hmac_digest; | |
329 | ||
330 | aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); | |
331 | BUG_ON(!aalg_desc); | |
332 | ||
333 | if (aalg_desc->uinfo.auth.icv_fullbits/8 != | |
334 | crypto_tfm_alg_digestsize(esp->auth.tfm)) { | |
335 | printk(KERN_INFO "ESP: %s digestsize %u != %hu\n", | |
336 | x->aalg->alg_name, | |
337 | crypto_tfm_alg_digestsize(esp->auth.tfm), | |
338 | aalg_desc->uinfo.auth.icv_fullbits/8); | |
339 | goto error; | |
340 | } | |
341 | ||
342 | esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8; | |
343 | esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8; | |
344 | ||
345 | esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL); | |
346 | if (!esp->auth.work_icv) | |
347 | goto error; | |
348 | } | |
349 | esp->conf.key = x->ealg->alg_key; | |
350 | esp->conf.key_len = (x->ealg->alg_key_len+7)/8; | |
351 | if (x->props.ealgo == SADB_EALG_NULL) | |
352 | esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_ECB); | |
353 | else | |
354 | esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_CBC); | |
355 | if (esp->conf.tfm == NULL) | |
356 | goto error; | |
357 | esp->conf.ivlen = crypto_tfm_alg_ivsize(esp->conf.tfm); | |
358 | esp->conf.padlen = 0; | |
359 | if (esp->conf.ivlen) { | |
360 | esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL); | |
361 | if (unlikely(esp->conf.ivec == NULL)) | |
362 | goto error; | |
363 | get_random_bytes(esp->conf.ivec, esp->conf.ivlen); | |
364 | } | |
365 | if (crypto_cipher_setkey(esp->conf.tfm, esp->conf.key, esp->conf.key_len)) | |
366 | goto error; | |
367 | x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen; | |
368 | if (x->props.mode) | |
369 | x->props.header_len += sizeof(struct ipv6hdr); | |
370 | x->data = esp; | |
371 | return 0; | |
372 | ||
373 | error: | |
374 | x->data = esp; | |
375 | esp6_destroy(x); | |
376 | x->data = NULL; | |
377 | return -EINVAL; | |
378 | } | |
379 | ||
380 | static struct xfrm_type esp6_type = | |
381 | { | |
382 | .description = "ESP6", | |
383 | .owner = THIS_MODULE, | |
384 | .proto = IPPROTO_ESP, | |
385 | .init_state = esp6_init_state, | |
386 | .destructor = esp6_destroy, | |
387 | .get_max_size = esp6_get_max_size, | |
388 | .input = esp6_input, | |
389 | .output = esp6_output | |
390 | }; | |
391 | ||
392 | static struct inet6_protocol esp6_protocol = { | |
393 | .handler = xfrm6_rcv, | |
394 | .err_handler = esp6_err, | |
395 | .flags = INET6_PROTO_NOPOLICY, | |
396 | }; | |
397 | ||
398 | static int __init esp6_init(void) | |
399 | { | |
400 | if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { | |
401 | printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n"); | |
402 | return -EAGAIN; | |
403 | } | |
404 | if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) { | |
405 | printk(KERN_INFO "ipv6 esp init: can't add protocol\n"); | |
406 | xfrm_unregister_type(&esp6_type, AF_INET6); | |
407 | return -EAGAIN; | |
408 | } | |
409 | ||
410 | return 0; | |
411 | } | |
412 | ||
413 | static void __exit esp6_fini(void) | |
414 | { | |
415 | if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0) | |
416 | printk(KERN_INFO "ipv6 esp close: can't remove protocol\n"); | |
417 | if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0) | |
418 | printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n"); | |
419 | } | |
420 | ||
421 | module_init(esp6_init); | |
422 | module_exit(esp6_fini); | |
423 | ||
424 | MODULE_LICENSE("GPL"); |