Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Copyright (C)2002 USAGI/WIDE Project | |
1ab1457c | 3 | * |
1da177e4 LT |
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. | |
1ab1457c | 8 | * |
1da177e4 LT |
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. | |
1ab1457c | 13 | * |
1da177e4 LT |
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 | * | |
1ab1457c | 20 | * Mitsuru KANDA @USAGI : IPv6 Support |
1da177e4 LT |
21 | * Kazunori MIYAZAWA @USAGI : |
22 | * Kunihiro Ishiguro <kunihiro@ipinfusion.com> | |
1ab1457c | 23 | * |
1da177e4 LT |
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; | |
1da177e4 LT |
45 | struct ipv6hdr *top_iph; |
46 | struct ipv6_esp_hdr *esph; | |
6b7326c8 HX |
47 | struct crypto_blkcipher *tfm; |
48 | struct blkcipher_desc desc; | |
1da177e4 LT |
49 | struct sk_buff *trailer; |
50 | int blksize; | |
51 | int clen; | |
52 | int alen; | |
53 | int nfrags; | |
ea2ae17d ACM |
54 | struct esp_data *esp = x->data; |
55 | int hdr_len = (skb_transport_offset(skb) + | |
56 | sizeof(*esph) + esp->conf.ivlen); | |
1da177e4 LT |
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; | |
6b7326c8 HX |
69 | desc.tfm = tfm; |
70 | desc.flags = 0; | |
71 | blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4); | |
a02a6422 | 72 | clen = ALIGN(clen + 2, blksize); |
1da177e4 | 73 | if (esp->conf.padlen) |
a02a6422 | 74 | clen = ALIGN(clen, esp->conf.padlen); |
1da177e4 LT |
75 | |
76 | if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) { | |
77 | goto error; | |
78 | } | |
79 | ||
80 | /* Fill padding... */ | |
81 | do { | |
82 | int i; | |
83 | for (i=0; i<clen-skb->len - 2; i++) | |
84 | *(u8*)(trailer->tail + i) = i+1; | |
85 | } while (0); | |
86 | *(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2; | |
87 | pskb_put(skb, trailer, clen - skb->len); | |
88 | ||
89 | top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len); | |
9c70220b | 90 | esph = (struct ipv6_esp_hdr *)skb_transport_header(skb); |
1da177e4 | 91 | top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph)); |
d56f90a7 ACM |
92 | *(u8 *)(trailer->tail - 1) = *skb_network_header(skb); |
93 | *skb_network_header(skb) = IPPROTO_ESP; | |
1da177e4 LT |
94 | |
95 | esph->spi = x->id.spi; | |
96 | esph->seq_no = htonl(++x->replay.oseq); | |
9500e8a8 | 97 | xfrm_aevent_doreplay(x); |
1da177e4 | 98 | |
e4bec827 DM |
99 | if (esp->conf.ivlen) { |
100 | if (unlikely(!esp->conf.ivinitted)) { | |
101 | get_random_bytes(esp->conf.ivec, esp->conf.ivlen); | |
102 | esp->conf.ivinitted = 1; | |
103 | } | |
6b7326c8 | 104 | crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen); |
e4bec827 | 105 | } |
1da177e4 LT |
106 | |
107 | do { | |
108 | struct scatterlist *sg = &esp->sgbuf[0]; | |
109 | ||
110 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { | |
111 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); | |
112 | if (!sg) | |
113 | goto error; | |
114 | } | |
115 | skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen); | |
6b7326c8 | 116 | err = crypto_blkcipher_encrypt(&desc, sg, sg, clen); |
1da177e4 LT |
117 | if (unlikely(sg != &esp->sgbuf[0])) |
118 | kfree(sg); | |
119 | } while (0); | |
120 | ||
6b7326c8 HX |
121 | if (unlikely(err)) |
122 | goto error; | |
123 | ||
1da177e4 | 124 | if (esp->conf.ivlen) { |
6b7326c8 HX |
125 | memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen); |
126 | crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen); | |
1da177e4 LT |
127 | } |
128 | ||
129 | if (esp->auth.icv_full_len) { | |
07d4ee58 HX |
130 | err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data, |
131 | sizeof(*esph) + esp->conf.ivlen + clen); | |
132 | memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen); | |
1da177e4 LT |
133 | } |
134 | ||
1da177e4 LT |
135 | error: |
136 | return err; | |
137 | } | |
138 | ||
e695633e | 139 | static int esp6_input(struct xfrm_state *x, struct sk_buff *skb) |
1da177e4 LT |
140 | { |
141 | struct ipv6hdr *iph; | |
142 | struct ipv6_esp_hdr *esph; | |
143 | struct esp_data *esp = x->data; | |
6b7326c8 HX |
144 | struct crypto_blkcipher *tfm = esp->conf.tfm; |
145 | struct blkcipher_desc desc = { .tfm = tfm }; | |
1da177e4 | 146 | struct sk_buff *trailer; |
6b7326c8 | 147 | int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4); |
1da177e4 LT |
148 | int alen = esp->auth.icv_trunc_len; |
149 | int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen; | |
cfe1fc77 | 150 | int hdr_len = skb_network_header_len(skb); |
1da177e4 | 151 | int nfrags; |
1da177e4 LT |
152 | int ret = 0; |
153 | ||
154 | if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) { | |
155 | ret = -EINVAL; | |
31a4ab93 | 156 | goto out; |
1da177e4 LT |
157 | } |
158 | ||
159 | if (elen <= 0 || (elen & (blksize-1))) { | |
160 | ret = -EINVAL; | |
31a4ab93 | 161 | goto out; |
1da177e4 | 162 | } |
1da177e4 LT |
163 | |
164 | /* If integrity check is required, do this. */ | |
1ab1457c | 165 | if (esp->auth.icv_full_len) { |
07d4ee58 | 166 | u8 sum[alen]; |
1da177e4 | 167 | |
07d4ee58 HX |
168 | ret = esp_mac_digest(esp, skb, 0, skb->len - alen); |
169 | if (ret) | |
170 | goto out; | |
1da177e4 | 171 | |
07d4ee58 | 172 | if (skb_copy_bits(skb, skb->len - alen, sum, alen)) |
1da177e4 LT |
173 | BUG(); |
174 | ||
07d4ee58 | 175 | if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) { |
1da177e4 LT |
176 | x->stats.integrity_failed++; |
177 | ret = -EINVAL; | |
178 | goto out; | |
179 | } | |
180 | } | |
181 | ||
182 | if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) { | |
183 | ret = -EINVAL; | |
184 | goto out; | |
185 | } | |
186 | ||
187 | skb->ip_summed = CHECKSUM_NONE; | |
188 | ||
189 | esph = (struct ipv6_esp_hdr*)skb->data; | |
0660e03f | 190 | iph = ipv6_hdr(skb); |
1da177e4 LT |
191 | |
192 | /* Get ivec. This can be wrong, check against another impls. */ | |
193 | if (esp->conf.ivlen) | |
6b7326c8 | 194 | crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen); |
1da177e4 | 195 | |
1ab1457c | 196 | { |
1da177e4 LT |
197 | u8 nexthdr[2]; |
198 | struct scatterlist *sg = &esp->sgbuf[0]; | |
199 | u8 padlen; | |
200 | ||
201 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { | |
202 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); | |
203 | if (!sg) { | |
204 | ret = -ENOMEM; | |
205 | goto out; | |
206 | } | |
207 | } | |
208 | skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen); | |
6b7326c8 | 209 | ret = crypto_blkcipher_decrypt(&desc, sg, sg, elen); |
1da177e4 LT |
210 | if (unlikely(sg != &esp->sgbuf[0])) |
211 | kfree(sg); | |
6b7326c8 HX |
212 | if (unlikely(ret)) |
213 | goto out; | |
1da177e4 LT |
214 | |
215 | if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2)) | |
216 | BUG(); | |
217 | ||
218 | padlen = nexthdr[0]; | |
219 | if (padlen+2 >= elen) { | |
64ce2073 | 220 | LIMIT_NETDEBUG(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen); |
1da177e4 LT |
221 | ret = -EINVAL; |
222 | goto out; | |
223 | } | |
1ab1457c | 224 | /* ... check padding bits here. Silly. :-) */ |
1da177e4 LT |
225 | |
226 | pskb_trim(skb, skb->len - alen - padlen - 2); | |
1da177e4 LT |
227 | ret = nexthdr[1]; |
228 | } | |
229 | ||
967b05f6 ACM |
230 | __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen); |
231 | skb_set_transport_header(skb, -hdr_len); | |
1da177e4 | 232 | out: |
1da177e4 LT |
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; | |
6b7326c8 | 239 | u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4); |
1da177e4 | 240 | |
7e49e6de | 241 | if (x->props.mode == XFRM_MODE_TUNNEL) { |
a02a6422 | 242 | mtu = ALIGN(mtu + 2, blksize); |
1da177e4 LT |
243 | } else { |
244 | /* The worst case. */ | |
d4875b04 HX |
245 | u32 padsize = ((blksize - 1) & 7) + 1; |
246 | mtu = ALIGN(mtu + 2, padsize) + blksize - padsize; | |
1da177e4 LT |
247 | } |
248 | if (esp->conf.padlen) | |
a02a6422 | 249 | mtu = ALIGN(mtu, esp->conf.padlen); |
1da177e4 | 250 | |
73d4f84f | 251 | return mtu + x->props.header_len + esp->auth.icv_trunc_len; |
1da177e4 LT |
252 | } |
253 | ||
254 | static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, | |
1ab1457c | 255 | int type, int code, int offset, __be32 info) |
1da177e4 LT |
256 | { |
257 | struct ipv6hdr *iph = (struct ipv6hdr*)skb->data; | |
258 | struct ipv6_esp_hdr *esph = (struct ipv6_esp_hdr*)(skb->data+offset); | |
259 | struct xfrm_state *x; | |
260 | ||
1ab1457c | 261 | if (type != ICMPV6_DEST_UNREACH && |
1da177e4 LT |
262 | type != ICMPV6_PKT_TOOBIG) |
263 | return; | |
264 | ||
265 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6); | |
266 | if (!x) | |
267 | return; | |
1ab1457c | 268 | printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" NIP6_FMT "\n", |
1da177e4 LT |
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 | ||
6b7326c8 | 280 | crypto_free_blkcipher(esp->conf.tfm); |
573dbd95 JJ |
281 | esp->conf.tfm = NULL; |
282 | kfree(esp->conf.ivec); | |
283 | esp->conf.ivec = NULL; | |
07d4ee58 | 284 | crypto_free_hash(esp->auth.tfm); |
573dbd95 JJ |
285 | esp->auth.tfm = NULL; |
286 | kfree(esp->auth.work_icv); | |
287 | esp->auth.work_icv = NULL; | |
1da177e4 LT |
288 | kfree(esp); |
289 | } | |
290 | ||
72cb6962 | 291 | static int esp6_init_state(struct xfrm_state *x) |
1da177e4 LT |
292 | { |
293 | struct esp_data *esp = NULL; | |
6b7326c8 | 294 | struct crypto_blkcipher *tfm; |
1da177e4 LT |
295 | |
296 | /* null auth and encryption can have zero length keys */ | |
297 | if (x->aalg) { | |
298 | if (x->aalg->alg_key_len > 512) | |
299 | goto error; | |
300 | } | |
301 | if (x->ealg == NULL) | |
302 | goto error; | |
303 | ||
304 | if (x->encap) | |
305 | goto error; | |
306 | ||
0c600eda | 307 | esp = kzalloc(sizeof(*esp), GFP_KERNEL); |
1da177e4 LT |
308 | if (esp == NULL) |
309 | return -ENOMEM; | |
310 | ||
1da177e4 LT |
311 | if (x->aalg) { |
312 | struct xfrm_algo_desc *aalg_desc; | |
07d4ee58 | 313 | struct crypto_hash *hash; |
1da177e4 LT |
314 | |
315 | esp->auth.key = x->aalg->alg_key; | |
316 | esp->auth.key_len = (x->aalg->alg_key_len+7)/8; | |
07d4ee58 HX |
317 | hash = crypto_alloc_hash(x->aalg->alg_name, 0, |
318 | CRYPTO_ALG_ASYNC); | |
319 | if (IS_ERR(hash)) | |
320 | goto error; | |
321 | ||
322 | esp->auth.tfm = hash; | |
323 | if (crypto_hash_setkey(hash, esp->auth.key, esp->auth.key_len)) | |
1da177e4 | 324 | goto error; |
1ab1457c | 325 | |
1da177e4 LT |
326 | aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); |
327 | BUG_ON(!aalg_desc); | |
1ab1457c | 328 | |
1da177e4 | 329 | if (aalg_desc->uinfo.auth.icv_fullbits/8 != |
07d4ee58 HX |
330 | crypto_hash_digestsize(hash)) { |
331 | NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n", | |
332 | x->aalg->alg_name, | |
333 | crypto_hash_digestsize(hash), | |
334 | aalg_desc->uinfo.auth.icv_fullbits/8); | |
335 | goto error; | |
1da177e4 | 336 | } |
1ab1457c | 337 | |
1da177e4 LT |
338 | esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8; |
339 | esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8; | |
1ab1457c | 340 | |
1da177e4 LT |
341 | esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL); |
342 | if (!esp->auth.work_icv) | |
343 | goto error; | |
344 | } | |
345 | esp->conf.key = x->ealg->alg_key; | |
346 | esp->conf.key_len = (x->ealg->alg_key_len+7)/8; | |
6b7326c8 HX |
347 | tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC); |
348 | if (IS_ERR(tfm)) | |
1da177e4 | 349 | goto error; |
6b7326c8 HX |
350 | esp->conf.tfm = tfm; |
351 | esp->conf.ivlen = crypto_blkcipher_ivsize(tfm); | |
1da177e4 LT |
352 | esp->conf.padlen = 0; |
353 | if (esp->conf.ivlen) { | |
354 | esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL); | |
355 | if (unlikely(esp->conf.ivec == NULL)) | |
356 | goto error; | |
e4bec827 | 357 | esp->conf.ivinitted = 0; |
1da177e4 | 358 | } |
6b7326c8 | 359 | if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len)) |
1da177e4 LT |
360 | goto error; |
361 | x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen; | |
7e49e6de | 362 | if (x->props.mode == XFRM_MODE_TUNNEL) |
1da177e4 LT |
363 | x->props.header_len += sizeof(struct ipv6hdr); |
364 | x->data = esp; | |
365 | return 0; | |
366 | ||
367 | error: | |
368 | x->data = esp; | |
369 | esp6_destroy(x); | |
370 | x->data = NULL; | |
371 | return -EINVAL; | |
372 | } | |
373 | ||
374 | static struct xfrm_type esp6_type = | |
375 | { | |
376 | .description = "ESP6", | |
377 | .owner = THIS_MODULE, | |
378 | .proto = IPPROTO_ESP, | |
379 | .init_state = esp6_init_state, | |
380 | .destructor = esp6_destroy, | |
381 | .get_max_size = esp6_get_max_size, | |
382 | .input = esp6_input, | |
aee5adb4 MN |
383 | .output = esp6_output, |
384 | .hdr_offset = xfrm6_find_1stfragopt, | |
1da177e4 LT |
385 | }; |
386 | ||
387 | static struct inet6_protocol esp6_protocol = { | |
388 | .handler = xfrm6_rcv, | |
389 | .err_handler = esp6_err, | |
390 | .flags = INET6_PROTO_NOPOLICY, | |
391 | }; | |
392 | ||
393 | static int __init esp6_init(void) | |
394 | { | |
395 | if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { | |
396 | printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n"); | |
397 | return -EAGAIN; | |
398 | } | |
399 | if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) { | |
400 | printk(KERN_INFO "ipv6 esp init: can't add protocol\n"); | |
401 | xfrm_unregister_type(&esp6_type, AF_INET6); | |
402 | return -EAGAIN; | |
403 | } | |
404 | ||
405 | return 0; | |
406 | } | |
407 | ||
408 | static void __exit esp6_fini(void) | |
409 | { | |
410 | if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0) | |
411 | printk(KERN_INFO "ipv6 esp close: can't remove protocol\n"); | |
412 | if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0) | |
413 | printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n"); | |
414 | } | |
415 | ||
416 | module_init(esp6_init); | |
417 | module_exit(esp6_fini); | |
418 | ||
419 | MODULE_LICENSE("GPL"); |