Commit | Line | Data |
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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 | ||
6b7326c8 | 27 | #include <linux/err.h> |
1da177e4 LT |
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> | |
a02a6422 | 34 | #include <linux/kernel.h> |
1da177e4 LT |
35 | #include <linux/pfkeyv2.h> |
36 | #include <linux/random.h> | |
37 | #include <net/icmp.h> | |
38 | #include <net/ipv6.h> | |
14c85021 | 39 | #include <net/protocol.h> |
1da177e4 LT |
40 | #include <linux/icmpv6.h> |
41 | ||
42 | static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) | |
43 | { | |
44 | int err; | |
45 | int hdr_len; | |
46 | struct ipv6hdr *top_iph; | |
47 | struct ipv6_esp_hdr *esph; | |
6b7326c8 HX |
48 | struct crypto_blkcipher *tfm; |
49 | struct blkcipher_desc desc; | |
1da177e4 LT |
50 | struct esp_data *esp; |
51 | struct sk_buff *trailer; | |
52 | int blksize; | |
53 | int clen; | |
54 | int alen; | |
55 | int nfrags; | |
56 | ||
57 | esp = x->data; | |
58 | hdr_len = skb->h.raw - skb->data + | |
59 | sizeof(*esph) + esp->conf.ivlen; | |
60 | ||
61 | /* Strip IP+ESP header. */ | |
62 | __skb_pull(skb, hdr_len); | |
63 | ||
64 | /* Now skb is pure payload to encrypt */ | |
65 | err = -ENOMEM; | |
66 | ||
67 | /* Round to block size */ | |
68 | clen = skb->len; | |
69 | ||
70 | alen = esp->auth.icv_trunc_len; | |
71 | tfm = esp->conf.tfm; | |
6b7326c8 HX |
72 | desc.tfm = tfm; |
73 | desc.flags = 0; | |
74 | blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4); | |
a02a6422 | 75 | clen = ALIGN(clen + 2, blksize); |
1da177e4 | 76 | if (esp->conf.padlen) |
a02a6422 | 77 | clen = ALIGN(clen, esp->conf.padlen); |
1da177e4 LT |
78 | |
79 | if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) { | |
80 | goto error; | |
81 | } | |
82 | ||
83 | /* Fill padding... */ | |
84 | do { | |
85 | int i; | |
86 | for (i=0; i<clen-skb->len - 2; i++) | |
87 | *(u8*)(trailer->tail + i) = i+1; | |
88 | } while (0); | |
89 | *(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2; | |
90 | pskb_put(skb, trailer, clen - skb->len); | |
91 | ||
92 | top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len); | |
93 | esph = (struct ipv6_esp_hdr *)skb->h.raw; | |
94 | top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph)); | |
95 | *(u8*)(trailer->tail - 1) = *skb->nh.raw; | |
96 | *skb->nh.raw = IPPROTO_ESP; | |
97 | ||
98 | esph->spi = x->id.spi; | |
99 | esph->seq_no = htonl(++x->replay.oseq); | |
9500e8a8 | 100 | xfrm_aevent_doreplay(x); |
1da177e4 | 101 | |
e4bec827 DM |
102 | if (esp->conf.ivlen) { |
103 | if (unlikely(!esp->conf.ivinitted)) { | |
104 | get_random_bytes(esp->conf.ivec, esp->conf.ivlen); | |
105 | esp->conf.ivinitted = 1; | |
106 | } | |
6b7326c8 | 107 | crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen); |
e4bec827 | 108 | } |
1da177e4 LT |
109 | |
110 | do { | |
111 | struct scatterlist *sg = &esp->sgbuf[0]; | |
112 | ||
113 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { | |
114 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); | |
115 | if (!sg) | |
116 | goto error; | |
117 | } | |
118 | skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen); | |
6b7326c8 | 119 | err = crypto_blkcipher_encrypt(&desc, sg, sg, clen); |
1da177e4 LT |
120 | if (unlikely(sg != &esp->sgbuf[0])) |
121 | kfree(sg); | |
122 | } while (0); | |
123 | ||
6b7326c8 HX |
124 | if (unlikely(err)) |
125 | goto error; | |
126 | ||
1da177e4 | 127 | if (esp->conf.ivlen) { |
6b7326c8 HX |
128 | memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen); |
129 | crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen); | |
1da177e4 LT |
130 | } |
131 | ||
132 | if (esp->auth.icv_full_len) { | |
07d4ee58 HX |
133 | err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data, |
134 | sizeof(*esph) + esp->conf.ivlen + clen); | |
135 | memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen); | |
1da177e4 LT |
136 | } |
137 | ||
1da177e4 LT |
138 | error: |
139 | return err; | |
140 | } | |
141 | ||
e695633e | 142 | static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) |
1da177e4 LT |
143 | { |
144 | struct ipv6hdr *iph; | |
145 | struct ipv6_esp_hdr *esph; | |
146 | struct esp_data *esp = x->data; | |
6b7326c8 HX |
147 | struct crypto_blkcipher *tfm = esp->conf.tfm; |
148 | struct blkcipher_desc desc = { .tfm = tfm }; | |
1da177e4 | 149 | struct sk_buff *trailer; |
6b7326c8 | 150 | int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4); |
1da177e4 LT |
151 | int alen = esp->auth.icv_trunc_len; |
152 | int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen; | |
153 | ||
154 | int hdr_len = skb->h.raw - skb->nh.raw; | |
155 | int nfrags; | |
1da177e4 LT |
156 | int ret = 0; |
157 | ||
158 | if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) { | |
159 | ret = -EINVAL; | |
31a4ab93 | 160 | goto out; |
1da177e4 LT |
161 | } |
162 | ||
163 | if (elen <= 0 || (elen & (blksize-1))) { | |
164 | ret = -EINVAL; | |
31a4ab93 | 165 | goto out; |
1da177e4 | 166 | } |
1da177e4 LT |
167 | |
168 | /* If integrity check is required, do this. */ | |
169 | if (esp->auth.icv_full_len) { | |
07d4ee58 | 170 | u8 sum[alen]; |
1da177e4 | 171 | |
07d4ee58 HX |
172 | ret = esp_mac_digest(esp, skb, 0, skb->len - alen); |
173 | if (ret) | |
174 | goto out; | |
1da177e4 | 175 | |
07d4ee58 | 176 | if (skb_copy_bits(skb, skb->len - alen, sum, alen)) |
1da177e4 LT |
177 | BUG(); |
178 | ||
07d4ee58 | 179 | if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) { |
1da177e4 LT |
180 | x->stats.integrity_failed++; |
181 | ret = -EINVAL; | |
182 | goto out; | |
183 | } | |
184 | } | |
185 | ||
186 | if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) { | |
187 | ret = -EINVAL; | |
188 | goto out; | |
189 | } | |
190 | ||
191 | skb->ip_summed = CHECKSUM_NONE; | |
192 | ||
193 | esph = (struct ipv6_esp_hdr*)skb->data; | |
194 | iph = skb->nh.ipv6h; | |
195 | ||
196 | /* Get ivec. This can be wrong, check against another impls. */ | |
197 | if (esp->conf.ivlen) | |
6b7326c8 | 198 | crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen); |
1da177e4 LT |
199 | |
200 | { | |
201 | u8 nexthdr[2]; | |
202 | struct scatterlist *sg = &esp->sgbuf[0]; | |
203 | u8 padlen; | |
204 | ||
205 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { | |
206 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); | |
207 | if (!sg) { | |
208 | ret = -ENOMEM; | |
209 | goto out; | |
210 | } | |
211 | } | |
212 | skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen); | |
6b7326c8 | 213 | ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen); |
1da177e4 LT |
214 | if (unlikely(sg != &esp->sgbuf[0])) |
215 | kfree(sg); | |
6b7326c8 HX |
216 | if (unlikely(ret)) |
217 | goto out; | |
1da177e4 LT |
218 | |
219 | if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2)) | |
220 | BUG(); | |
221 | ||
222 | padlen = nexthdr[0]; | |
223 | if (padlen+2 >= elen) { | |
64ce2073 | 224 | LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen); |
1da177e4 LT |
225 | ret = -EINVAL; |
226 | goto out; | |
227 | } | |
228 | /* ... check padding bits here. Silly. :-) */ | |
229 | ||
230 | pskb_trim(skb, skb->len - alen - padlen - 2); | |
1da177e4 LT |
231 | ret = nexthdr[1]; |
232 | } | |
233 | ||
31a4ab93 HX |
234 | skb->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - hdr_len; |
235 | ||
1da177e4 | 236 | out: |
1da177e4 LT |
237 | return ret; |
238 | } | |
239 | ||
240 | static u32 esp6_get_max_size(struct xfrm_state *x, int mtu) | |
241 | { | |
242 | struct esp_data *esp = x->data; | |
6b7326c8 | 243 | u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4); |
1da177e4 | 244 | |
7e49e6de | 245 | if (x->props.mode == XFRM_MODE_TUNNEL) { |
a02a6422 | 246 | mtu = ALIGN(mtu + 2, blksize); |
1da177e4 LT |
247 | } else { |
248 | /* The worst case. */ | |
d4875b04 HX |
249 | u32 padsize = ((blksize - 1) & 7) + 1; |
250 | mtu = ALIGN(mtu + 2, padsize) + blksize - padsize; | |
1da177e4 LT |
251 | } |
252 | if (esp->conf.padlen) | |
a02a6422 | 253 | mtu = ALIGN(mtu, esp->conf.padlen); |
1da177e4 | 254 | |
73d4f84f | 255 | return mtu + x->props.header_len + esp->auth.icv_trunc_len; |
1da177e4 LT |
256 | } |
257 | ||
258 | static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, | |
04ce6909 | 259 | int type, int code, int offset, __be32 info) |
1da177e4 LT |
260 | { |
261 | struct ipv6hdr *iph = (struct ipv6hdr*)skb->data; | |
262 | struct ipv6_esp_hdr *esph = (struct ipv6_esp_hdr*)(skb->data+offset); | |
263 | struct xfrm_state *x; | |
264 | ||
265 | if (type != ICMPV6_DEST_UNREACH && | |
266 | type != ICMPV6_PKT_TOOBIG) | |
267 | return; | |
268 | ||
269 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6); | |
270 | if (!x) | |
271 | return; | |
46b86a2d | 272 | printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n", |
1da177e4 LT |
273 | ntohl(esph->spi), NIP6(iph->daddr)); |
274 | xfrm_state_put(x); | |
275 | } | |
276 | ||
277 | static void esp6_destroy(struct xfrm_state *x) | |
278 | { | |
279 | struct esp_data *esp = x->data; | |
280 | ||
281 | if (!esp) | |
282 | return; | |
283 | ||
6b7326c8 | 284 | crypto_free_blkcipher(esp->conf.tfm); |
573dbd95 JJ |
285 | esp->conf.tfm = NULL; |
286 | kfree(esp->conf.ivec); | |
287 | esp->conf.ivec = NULL; | |
07d4ee58 | 288 | crypto_free_hash(esp->auth.tfm); |
573dbd95 JJ |
289 | esp->auth.tfm = NULL; |
290 | kfree(esp->auth.work_icv); | |
291 | esp->auth.work_icv = NULL; | |
1da177e4 LT |
292 | kfree(esp); |
293 | } | |
294 | ||
72cb6962 | 295 | static int esp6_init_state(struct xfrm_state *x) |
1da177e4 LT |
296 | { |
297 | struct esp_data *esp = NULL; | |
6b7326c8 | 298 | struct crypto_blkcipher *tfm; |
1da177e4 LT |
299 | |
300 | /* null auth and encryption can have zero length keys */ | |
301 | if (x->aalg) { | |
302 | if (x->aalg->alg_key_len > 512) | |
303 | goto error; | |
304 | } | |
305 | if (x->ealg == NULL) | |
306 | goto error; | |
307 | ||
308 | if (x->encap) | |
309 | goto error; | |
310 | ||
0c600eda | 311 | esp = kzalloc(sizeof(*esp), GFP_KERNEL); |
1da177e4 LT |
312 | if (esp == NULL) |
313 | return -ENOMEM; | |
314 | ||
1da177e4 LT |
315 | if (x->aalg) { |
316 | struct xfrm_algo_desc *aalg_desc; | |
07d4ee58 | 317 | struct crypto_hash *hash; |
1da177e4 LT |
318 | |
319 | esp->auth.key = x->aalg->alg_key; | |
320 | esp->auth.key_len = (x->aalg->alg_key_len+7)/8; | |
07d4ee58 HX |
321 | hash = crypto_alloc_hash(x->aalg->alg_name, 0, |
322 | CRYPTO_ALG_ASYNC); | |
323 | if (IS_ERR(hash)) | |
324 | goto error; | |
325 | ||
326 | esp->auth.tfm = hash; | |
327 | if (crypto_hash_setkey(hash, esp->auth.key, esp->auth.key_len)) | |
1da177e4 | 328 | goto error; |
1da177e4 LT |
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 != | |
07d4ee58 HX |
334 | crypto_hash_digestsize(hash)) { |
335 | NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n", | |
336 | x->aalg->alg_name, | |
337 | crypto_hash_digestsize(hash), | |
338 | aalg_desc->uinfo.auth.icv_fullbits/8); | |
339 | goto error; | |
1da177e4 LT |
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; | |
6b7326c8 HX |
351 | tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC); |
352 | if (IS_ERR(tfm)) | |
1da177e4 | 353 | goto error; |
6b7326c8 HX |
354 | esp->conf.tfm = tfm; |
355 | esp->conf.ivlen = crypto_blkcipher_ivsize(tfm); | |
1da177e4 LT |
356 | esp->conf.padlen = 0; |
357 | if (esp->conf.ivlen) { | |
358 | esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL); | |
359 | if (unlikely(esp->conf.ivec == NULL)) | |
360 | goto error; | |
e4bec827 | 361 | esp->conf.ivinitted = 0; |
1da177e4 | 362 | } |
6b7326c8 | 363 | if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len)) |
1da177e4 LT |
364 | goto error; |
365 | x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen; | |
7e49e6de | 366 | if (x->props.mode == XFRM_MODE_TUNNEL) |
1da177e4 LT |
367 | x->props.header_len += sizeof(struct ipv6hdr); |
368 | x->data = esp; | |
369 | return 0; | |
370 | ||
371 | error: | |
372 | x->data = esp; | |
373 | esp6_destroy(x); | |
374 | x->data = NULL; | |
375 | return -EINVAL; | |
376 | } | |
377 | ||
378 | static struct xfrm_type esp6_type = | |
379 | { | |
380 | .description = "ESP6", | |
381 | .owner = THIS_MODULE, | |
382 | .proto = IPPROTO_ESP, | |
383 | .init_state = esp6_init_state, | |
384 | .destructor = esp6_destroy, | |
385 | .get_max_size = esp6_get_max_size, | |
386 | .input = esp6_input, | |
aee5adb4 MN |
387 | .output = esp6_output, |
388 | .hdr_offset = xfrm6_find_1stfragopt, | |
1da177e4 LT |
389 | }; |
390 | ||
391 | static struct inet6_protocol esp6_protocol = { | |
392 | .handler = xfrm6_rcv, | |
393 | .err_handler = esp6_err, | |
394 | .flags = INET6_PROTO_NOPOLICY, | |
395 | }; | |
396 | ||
397 | static int __init esp6_init(void) | |
398 | { | |
399 | if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { | |
400 | printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n"); | |
401 | return -EAGAIN; | |
402 | } | |
403 | if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) { | |
404 | printk(KERN_INFO "ipv6 esp init: can't add protocol\n"); | |
405 | xfrm_unregister_type(&esp6_type, AF_INET6); | |
406 | return -EAGAIN; | |
407 | } | |
408 | ||
409 | return 0; | |
410 | } | |
411 | ||
412 | static void __exit esp6_fini(void) | |
413 | { | |
414 | if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0) | |
415 | printk(KERN_INFO "ipv6 esp close: can't remove protocol\n"); | |
416 | if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0) | |
417 | printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n"); | |
418 | } | |
419 | ||
420 | module_init(esp6_init); | |
421 | module_exit(esp6_fini); | |
422 | ||
423 | MODULE_LICENSE("GPL"); |