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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/module.h> | |
28 | #include <net/ip.h> | |
29 | #include <net/xfrm.h> | |
30 | #include <net/esp.h> | |
31 | #include <asm/scatterlist.h> | |
32 | #include <linux/crypto.h> | |
33 | #include <linux/kernel.h> | |
34 | #include <linux/pfkeyv2.h> | |
35 | #include <linux/random.h> | |
36 | #include <net/icmp.h> | |
37 | #include <net/ipv6.h> | |
38 | #include <net/protocol.h> | |
39 | #include <linux/icmpv6.h> | |
40 | ||
41 | static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) | |
42 | { | |
43 | int err; | |
44 | int hdr_len; | |
45 | struct ipv6hdr *top_iph; | |
46 | struct ipv6_esp_hdr *esph; | |
47 | struct crypto_tfm *tfm; | |
48 | struct esp_data *esp; | |
49 | struct sk_buff *trailer; | |
50 | int blksize; | |
51 | int clen; | |
52 | int alen; | |
53 | int nfrags; | |
54 | ||
55 | esp = x->data; | |
56 | hdr_len = skb->h.raw - skb->data + | |
57 | sizeof(*esph) + esp->conf.ivlen; | |
58 | ||
59 | /* Strip IP+ESP header. */ | |
60 | __skb_pull(skb, hdr_len); | |
61 | ||
62 | /* Now skb is pure payload to encrypt */ | |
63 | err = -ENOMEM; | |
64 | ||
65 | /* Round to block size */ | |
66 | clen = skb->len; | |
67 | ||
68 | alen = esp->auth.icv_trunc_len; | |
69 | tfm = esp->conf.tfm; | |
70 | blksize = ALIGN(crypto_tfm_alg_blocksize(tfm), 4); | |
71 | clen = ALIGN(clen + 2, blksize); | |
72 | if (esp->conf.padlen) | |
73 | clen = ALIGN(clen, esp->conf.padlen); | |
74 | ||
75 | if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) { | |
76 | goto error; | |
77 | } | |
78 | ||
79 | /* Fill padding... */ | |
80 | do { | |
81 | int i; | |
82 | for (i=0; i<clen-skb->len - 2; i++) | |
83 | *(u8*)(trailer->tail + i) = i+1; | |
84 | } while (0); | |
85 | *(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2; | |
86 | pskb_put(skb, trailer, clen - skb->len); | |
87 | ||
88 | top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len); | |
89 | esph = (struct ipv6_esp_hdr *)skb->h.raw; | |
90 | top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph)); | |
91 | *(u8*)(trailer->tail - 1) = *skb->nh.raw; | |
92 | *skb->nh.raw = IPPROTO_ESP; | |
93 | ||
94 | esph->spi = x->id.spi; | |
95 | esph->seq_no = htonl(++x->replay.oseq); | |
96 | xfrm_aevent_doreplay(x); | |
97 | ||
98 | if (esp->conf.ivlen) | |
99 | crypto_cipher_set_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm)); | |
100 | ||
101 | do { | |
102 | struct scatterlist *sg = &esp->sgbuf[0]; | |
103 | ||
104 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { | |
105 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); | |
106 | if (!sg) | |
107 | goto error; | |
108 | } | |
109 | skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen); | |
110 | crypto_cipher_encrypt(tfm, sg, sg, clen); | |
111 | if (unlikely(sg != &esp->sgbuf[0])) | |
112 | kfree(sg); | |
113 | } while (0); | |
114 | ||
115 | if (esp->conf.ivlen) { | |
116 | memcpy(esph->enc_data, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm)); | |
117 | crypto_cipher_get_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm)); | |
118 | } | |
119 | ||
120 | if (esp->auth.icv_full_len) { | |
121 | esp->auth.icv(esp, skb, (u8*)esph-skb->data, | |
122 | sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen+clen, trailer->tail); | |
123 | pskb_put(skb, trailer, alen); | |
124 | } | |
125 | ||
126 | err = 0; | |
127 | ||
128 | error: | |
129 | return err; | |
130 | } | |
131 | ||
132 | static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) | |
133 | { | |
134 | struct ipv6hdr *iph; | |
135 | struct ipv6_esp_hdr *esph; | |
136 | struct esp_data *esp = x->data; | |
137 | struct sk_buff *trailer; | |
138 | int blksize = ALIGN(crypto_tfm_alg_blocksize(esp->conf.tfm), 4); | |
139 | int alen = esp->auth.icv_trunc_len; | |
140 | int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen; | |
141 | ||
142 | int hdr_len = skb->h.raw - skb->nh.raw; | |
143 | int nfrags; | |
144 | int ret = 0; | |
145 | ||
146 | if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) { | |
147 | ret = -EINVAL; | |
148 | goto out; | |
149 | } | |
150 | ||
151 | if (elen <= 0 || (elen & (blksize-1))) { | |
152 | ret = -EINVAL; | |
153 | goto out; | |
154 | } | |
155 | ||
156 | /* If integrity check is required, do this. */ | |
157 | if (esp->auth.icv_full_len) { | |
158 | u8 sum[esp->auth.icv_full_len]; | |
159 | u8 sum1[alen]; | |
160 | ||
161 | esp->auth.icv(esp, skb, 0, skb->len-alen, sum); | |
162 | ||
163 | if (skb_copy_bits(skb, skb->len-alen, sum1, alen)) | |
164 | BUG(); | |
165 | ||
166 | if (unlikely(memcmp(sum, sum1, alen))) { | |
167 | x->stats.integrity_failed++; | |
168 | ret = -EINVAL; | |
169 | goto out; | |
170 | } | |
171 | } | |
172 | ||
173 | if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) { | |
174 | ret = -EINVAL; | |
175 | goto out; | |
176 | } | |
177 | ||
178 | skb->ip_summed = CHECKSUM_NONE; | |
179 | ||
180 | esph = (struct ipv6_esp_hdr*)skb->data; | |
181 | iph = skb->nh.ipv6h; | |
182 | ||
183 | /* Get ivec. This can be wrong, check against another impls. */ | |
184 | if (esp->conf.ivlen) | |
185 | crypto_cipher_set_iv(esp->conf.tfm, esph->enc_data, crypto_tfm_alg_ivsize(esp->conf.tfm)); | |
186 | ||
187 | { | |
188 | u8 nexthdr[2]; | |
189 | struct scatterlist *sg = &esp->sgbuf[0]; | |
190 | u8 padlen; | |
191 | ||
192 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { | |
193 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); | |
194 | if (!sg) { | |
195 | ret = -ENOMEM; | |
196 | goto out; | |
197 | } | |
198 | } | |
199 | skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen); | |
200 | crypto_cipher_decrypt(esp->conf.tfm, sg, sg, elen); | |
201 | if (unlikely(sg != &esp->sgbuf[0])) | |
202 | kfree(sg); | |
203 | ||
204 | if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2)) | |
205 | BUG(); | |
206 | ||
207 | padlen = nexthdr[0]; | |
208 | if (padlen+2 >= elen) { | |
209 | LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen); | |
210 | ret = -EINVAL; | |
211 | goto out; | |
212 | } | |
213 | /* ... check padding bits here. Silly. :-) */ | |
214 | ||
215 | pskb_trim(skb, skb->len - alen - padlen - 2); | |
216 | ret = nexthdr[1]; | |
217 | } | |
218 | ||
219 | skb->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - hdr_len; | |
220 | ||
221 | out: | |
222 | return ret; | |
223 | } | |
224 | ||
225 | static u32 esp6_get_max_size(struct xfrm_state *x, int mtu) | |
226 | { | |
227 | struct esp_data *esp = x->data; | |
228 | u32 blksize = ALIGN(crypto_tfm_alg_blocksize(esp->conf.tfm), 4); | |
229 | ||
230 | if (x->props.mode) { | |
231 | mtu = ALIGN(mtu + 2, blksize); | |
232 | } else { | |
233 | /* The worst case. */ | |
234 | u32 padsize = ((blksize - 1) & 7) + 1; | |
235 | mtu = ALIGN(mtu + 2, padsize) + blksize - padsize; | |
236 | } | |
237 | if (esp->conf.padlen) | |
238 | mtu = ALIGN(mtu, esp->conf.padlen); | |
239 | ||
240 | return mtu + x->props.header_len + esp->auth.icv_trunc_len; | |
241 | } | |
242 | ||
243 | static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, | |
244 | int type, int code, int offset, __u32 info) | |
245 | { | |
246 | struct ipv6hdr *iph = (struct ipv6hdr*)skb->data; | |
247 | struct ipv6_esp_hdr *esph = (struct ipv6_esp_hdr*)(skb->data+offset); | |
248 | struct xfrm_state *x; | |
249 | ||
250 | if (type != ICMPV6_DEST_UNREACH && | |
251 | type != ICMPV6_PKT_TOOBIG) | |
252 | return; | |
253 | ||
254 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6); | |
255 | if (!x) | |
256 | return; | |
257 | printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n", | |
258 | ntohl(esph->spi), NIP6(iph->daddr)); | |
259 | xfrm_state_put(x); | |
260 | } | |
261 | ||
262 | static void esp6_destroy(struct xfrm_state *x) | |
263 | { | |
264 | struct esp_data *esp = x->data; | |
265 | ||
266 | if (!esp) | |
267 | return; | |
268 | ||
269 | crypto_free_tfm(esp->conf.tfm); | |
270 | esp->conf.tfm = NULL; | |
271 | kfree(esp->conf.ivec); | |
272 | esp->conf.ivec = NULL; | |
273 | crypto_free_tfm(esp->auth.tfm); | |
274 | esp->auth.tfm = NULL; | |
275 | kfree(esp->auth.work_icv); | |
276 | esp->auth.work_icv = NULL; | |
277 | kfree(esp); | |
278 | } | |
279 | ||
280 | static int esp6_init_state(struct xfrm_state *x) | |
281 | { | |
282 | struct esp_data *esp = NULL; | |
283 | ||
284 | /* null auth and encryption can have zero length keys */ | |
285 | if (x->aalg) { | |
286 | if (x->aalg->alg_key_len > 512) | |
287 | goto error; | |
288 | } | |
289 | if (x->ealg == NULL) | |
290 | goto error; | |
291 | ||
292 | if (x->encap) | |
293 | goto error; | |
294 | ||
295 | esp = kzalloc(sizeof(*esp), GFP_KERNEL); | |
296 | if (esp == NULL) | |
297 | return -ENOMEM; | |
298 | ||
299 | if (x->aalg) { | |
300 | struct xfrm_algo_desc *aalg_desc; | |
301 | ||
302 | esp->auth.key = x->aalg->alg_key; | |
303 | esp->auth.key_len = (x->aalg->alg_key_len+7)/8; | |
304 | esp->auth.tfm = crypto_alloc_tfm(x->aalg->alg_name, 0); | |
305 | if (esp->auth.tfm == NULL) | |
306 | goto error; | |
307 | esp->auth.icv = esp_hmac_digest; | |
308 | ||
309 | aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); | |
310 | BUG_ON(!aalg_desc); | |
311 | ||
312 | if (aalg_desc->uinfo.auth.icv_fullbits/8 != | |
313 | crypto_tfm_alg_digestsize(esp->auth.tfm)) { | |
314 | printk(KERN_INFO "ESP: %s digestsize %u != %hu\n", | |
315 | x->aalg->alg_name, | |
316 | crypto_tfm_alg_digestsize(esp->auth.tfm), | |
317 | aalg_desc->uinfo.auth.icv_fullbits/8); | |
318 | goto error; | |
319 | } | |
320 | ||
321 | esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8; | |
322 | esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8; | |
323 | ||
324 | esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL); | |
325 | if (!esp->auth.work_icv) | |
326 | goto error; | |
327 | } | |
328 | esp->conf.key = x->ealg->alg_key; | |
329 | esp->conf.key_len = (x->ealg->alg_key_len+7)/8; | |
330 | if (x->props.ealgo == SADB_EALG_NULL) | |
331 | esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_ECB); | |
332 | else | |
333 | esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_CBC); | |
334 | if (esp->conf.tfm == NULL) | |
335 | goto error; | |
336 | esp->conf.ivlen = crypto_tfm_alg_ivsize(esp->conf.tfm); | |
337 | esp->conf.padlen = 0; | |
338 | if (esp->conf.ivlen) { | |
339 | esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL); | |
340 | if (unlikely(esp->conf.ivec == NULL)) | |
341 | goto error; | |
342 | get_random_bytes(esp->conf.ivec, esp->conf.ivlen); | |
343 | } | |
344 | if (crypto_cipher_setkey(esp->conf.tfm, esp->conf.key, esp->conf.key_len)) | |
345 | goto error; | |
346 | x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen; | |
347 | if (x->props.mode) | |
348 | x->props.header_len += sizeof(struct ipv6hdr); | |
349 | x->data = esp; | |
350 | return 0; | |
351 | ||
352 | error: | |
353 | x->data = esp; | |
354 | esp6_destroy(x); | |
355 | x->data = NULL; | |
356 | return -EINVAL; | |
357 | } | |
358 | ||
359 | static struct xfrm_type esp6_type = | |
360 | { | |
361 | .description = "ESP6", | |
362 | .owner = THIS_MODULE, | |
363 | .proto = IPPROTO_ESP, | |
364 | .init_state = esp6_init_state, | |
365 | .destructor = esp6_destroy, | |
366 | .get_max_size = esp6_get_max_size, | |
367 | .input = esp6_input, | |
368 | .output = esp6_output | |
369 | }; | |
370 | ||
371 | static struct inet6_protocol esp6_protocol = { | |
372 | .handler = xfrm6_rcv, | |
373 | .err_handler = esp6_err, | |
374 | .flags = INET6_PROTO_NOPOLICY, | |
375 | }; | |
376 | ||
377 | static int __init esp6_init(void) | |
378 | { | |
379 | if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { | |
380 | printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n"); | |
381 | return -EAGAIN; | |
382 | } | |
383 | if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) { | |
384 | printk(KERN_INFO "ipv6 esp init: can't add protocol\n"); | |
385 | xfrm_unregister_type(&esp6_type, AF_INET6); | |
386 | return -EAGAIN; | |
387 | } | |
388 | ||
389 | return 0; | |
390 | } | |
391 | ||
392 | static void __exit esp6_fini(void) | |
393 | { | |
394 | if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0) | |
395 | printk(KERN_INFO "ipv6 esp close: can't remove protocol\n"); | |
396 | if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0) | |
397 | printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n"); | |
398 | } | |
399 | ||
400 | module_init(esp6_init); | |
401 | module_exit(esp6_fini); | |
402 | ||
403 | MODULE_LICENSE("GPL"); |