Commit | Line | Data |
---|---|---|
6b7326c8 | 1 | #include <linux/err.h> |
1da177e4 LT |
2 | #include <linux/module.h> |
3 | #include <net/ip.h> | |
4 | #include <net/xfrm.h> | |
5 | #include <net/esp.h> | |
6 | #include <asm/scatterlist.h> | |
7 | #include <linux/crypto.h> | |
a02a6422 | 8 | #include <linux/kernel.h> |
1da177e4 LT |
9 | #include <linux/pfkeyv2.h> |
10 | #include <linux/random.h> | |
11 | #include <net/icmp.h> | |
14c85021 | 12 | #include <net/protocol.h> |
1da177e4 LT |
13 | #include <net/udp.h> |
14 | ||
1da177e4 LT |
15 | static int esp_output(struct xfrm_state *x, struct sk_buff *skb) |
16 | { | |
17 | int err; | |
18 | struct iphdr *top_iph; | |
19 | struct ip_esp_hdr *esph; | |
6b7326c8 HX |
20 | struct crypto_blkcipher *tfm; |
21 | struct blkcipher_desc desc; | |
1da177e4 LT |
22 | struct esp_data *esp; |
23 | struct sk_buff *trailer; | |
24 | int blksize; | |
25 | int clen; | |
26 | int alen; | |
27 | int nfrags; | |
28 | ||
29 | /* Strip IP+ESP header. */ | |
30 | __skb_pull(skb, skb->h.raw - skb->data); | |
31 | /* Now skb is pure payload to encrypt */ | |
32 | ||
33 | err = -ENOMEM; | |
34 | ||
35 | /* Round to block size */ | |
36 | clen = skb->len; | |
37 | ||
38 | esp = x->data; | |
39 | alen = esp->auth.icv_trunc_len; | |
40 | tfm = esp->conf.tfm; | |
6b7326c8 HX |
41 | desc.tfm = tfm; |
42 | desc.flags = 0; | |
43 | blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4); | |
a02a6422 | 44 | clen = ALIGN(clen + 2, blksize); |
1da177e4 | 45 | if (esp->conf.padlen) |
a02a6422 | 46 | clen = ALIGN(clen, esp->conf.padlen); |
1da177e4 LT |
47 | |
48 | if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) | |
49 | goto error; | |
50 | ||
51 | /* Fill padding... */ | |
52 | do { | |
53 | int i; | |
54 | for (i=0; i<clen-skb->len - 2; i++) | |
55 | *(u8*)(trailer->tail + i) = i+1; | |
56 | } while (0); | |
57 | *(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2; | |
58 | pskb_put(skb, trailer, clen - skb->len); | |
59 | ||
60 | __skb_push(skb, skb->data - skb->nh.raw); | |
61 | top_iph = skb->nh.iph; | |
62 | esph = (struct ip_esp_hdr *)(skb->nh.raw + top_iph->ihl*4); | |
63 | top_iph->tot_len = htons(skb->len + alen); | |
64 | *(u8*)(trailer->tail - 1) = top_iph->protocol; | |
65 | ||
66 | /* this is non-NULL only with UDP Encapsulation */ | |
67 | if (x->encap) { | |
68 | struct xfrm_encap_tmpl *encap = x->encap; | |
69 | struct udphdr *uh; | |
d5a0a1e3 | 70 | __be32 *udpdata32; |
1da177e4 LT |
71 | |
72 | uh = (struct udphdr *)esph; | |
73 | uh->source = encap->encap_sport; | |
74 | uh->dest = encap->encap_dport; | |
75 | uh->len = htons(skb->len + alen - top_iph->ihl*4); | |
76 | uh->check = 0; | |
77 | ||
78 | switch (encap->encap_type) { | |
79 | default: | |
80 | case UDP_ENCAP_ESPINUDP: | |
81 | esph = (struct ip_esp_hdr *)(uh + 1); | |
82 | break; | |
83 | case UDP_ENCAP_ESPINUDP_NON_IKE: | |
d5a0a1e3 | 84 | udpdata32 = (__be32 *)(uh + 1); |
1da177e4 LT |
85 | udpdata32[0] = udpdata32[1] = 0; |
86 | esph = (struct ip_esp_hdr *)(udpdata32 + 2); | |
87 | break; | |
88 | } | |
89 | ||
90 | top_iph->protocol = IPPROTO_UDP; | |
91 | } else | |
92 | top_iph->protocol = IPPROTO_ESP; | |
93 | ||
94 | esph->spi = x->id.spi; | |
95 | esph->seq_no = htonl(++x->replay.oseq); | |
9500e8a8 | 96 | xfrm_aevent_doreplay(x); |
1da177e4 | 97 | |
e4bec827 DM |
98 | if (esp->conf.ivlen) { |
99 | if (unlikely(!esp->conf.ivinitted)) { | |
100 | get_random_bytes(esp->conf.ivec, esp->conf.ivlen); | |
101 | esp->conf.ivinitted = 1; | |
102 | } | |
6b7326c8 | 103 | crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen); |
e4bec827 | 104 | } |
1da177e4 LT |
105 | |
106 | do { | |
107 | struct scatterlist *sg = &esp->sgbuf[0]; | |
108 | ||
109 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { | |
110 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); | |
111 | if (!sg) | |
112 | goto error; | |
113 | } | |
114 | skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen); | |
6b7326c8 | 115 | err = crypto_blkcipher_encrypt(&desc, sg, sg, clen); |
1da177e4 LT |
116 | if (unlikely(sg != &esp->sgbuf[0])) |
117 | kfree(sg); | |
118 | } while (0); | |
119 | ||
6b7326c8 HX |
120 | if (unlikely(err)) |
121 | goto error; | |
122 | ||
1da177e4 | 123 | if (esp->conf.ivlen) { |
6b7326c8 HX |
124 | memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen); |
125 | crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen); | |
1da177e4 LT |
126 | } |
127 | ||
128 | if (esp->auth.icv_full_len) { | |
07d4ee58 HX |
129 | err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data, |
130 | sizeof(*esph) + esp->conf.ivlen + clen); | |
131 | memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen); | |
1da177e4 LT |
132 | } |
133 | ||
134 | ip_send_check(top_iph); | |
135 | ||
1da177e4 LT |
136 | error: |
137 | return err; | |
138 | } | |
139 | ||
140 | /* | |
141 | * Note: detecting truncated vs. non-truncated authentication data is very | |
142 | * expensive, so we only support truncated data, which is the recommended | |
143 | * and common case. | |
144 | */ | |
e695633e | 145 | static int esp_input(struct xfrm_state *x, struct sk_buff *skb) |
1da177e4 LT |
146 | { |
147 | struct iphdr *iph; | |
148 | struct ip_esp_hdr *esph; | |
149 | struct esp_data *esp = x->data; | |
6b7326c8 HX |
150 | struct crypto_blkcipher *tfm = esp->conf.tfm; |
151 | struct blkcipher_desc desc = { .tfm = tfm }; | |
1da177e4 | 152 | struct sk_buff *trailer; |
6b7326c8 | 153 | int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4); |
1da177e4 LT |
154 | int alen = esp->auth.icv_trunc_len; |
155 | int elen = skb->len - sizeof(struct ip_esp_hdr) - esp->conf.ivlen - alen; | |
156 | int nfrags; | |
31a4ab93 | 157 | int ihl; |
4bf05ece HX |
158 | u8 nexthdr[2]; |
159 | struct scatterlist *sg; | |
4bf05ece | 160 | int padlen; |
6b7326c8 | 161 | int err; |
1da177e4 LT |
162 | |
163 | if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr))) | |
164 | goto out; | |
165 | ||
166 | if (elen <= 0 || (elen & (blksize-1))) | |
167 | goto out; | |
168 | ||
169 | /* If integrity check is required, do this. */ | |
170 | if (esp->auth.icv_full_len) { | |
07d4ee58 | 171 | u8 sum[alen]; |
1da177e4 | 172 | |
07d4ee58 HX |
173 | err = esp_mac_digest(esp, skb, 0, skb->len - alen); |
174 | if (err) | |
175 | goto out; | |
176 | ||
177 | if (skb_copy_bits(skb, skb->len - alen, sum, alen)) | |
1da177e4 LT |
178 | BUG(); |
179 | ||
07d4ee58 | 180 | if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) { |
1da177e4 LT |
181 | x->stats.integrity_failed++; |
182 | goto out; | |
183 | } | |
184 | } | |
185 | ||
186 | if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) | |
187 | goto out; | |
188 | ||
189 | skb->ip_summed = CHECKSUM_NONE; | |
190 | ||
191 | esph = (struct ip_esp_hdr*)skb->data; | |
1da177e4 LT |
192 | |
193 | /* Get ivec. This can be wrong, check against another impls. */ | |
194 | if (esp->conf.ivlen) | |
6b7326c8 | 195 | crypto_blkcipher_set_iv(tfm, esph->enc_data, esp->conf.ivlen); |
1da177e4 | 196 | |
4bf05ece | 197 | sg = &esp->sgbuf[0]; |
1da177e4 | 198 | |
4bf05ece HX |
199 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { |
200 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); | |
201 | if (!sg) | |
202 | goto out; | |
203 | } | |
204 | skb_to_sgvec(skb, sg, sizeof(struct ip_esp_hdr) + esp->conf.ivlen, elen); | |
6b7326c8 | 205 | err = crypto_blkcipher_decrypt(&desc, sg, sg, elen); |
4bf05ece HX |
206 | if (unlikely(sg != &esp->sgbuf[0])) |
207 | kfree(sg); | |
6b7326c8 HX |
208 | if (unlikely(err)) |
209 | return err; | |
1da177e4 | 210 | |
4bf05ece HX |
211 | if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2)) |
212 | BUG(); | |
1da177e4 | 213 | |
4bf05ece HX |
214 | padlen = nexthdr[0]; |
215 | if (padlen+2 >= elen) | |
216 | goto out; | |
1da177e4 | 217 | |
e905a9ed | 218 | /* ... check padding bits here. Silly. :-) */ |
1da177e4 | 219 | |
31a4ab93 HX |
220 | iph = skb->nh.iph; |
221 | ihl = iph->ihl * 4; | |
222 | ||
752c1f4c HX |
223 | if (x->encap) { |
224 | struct xfrm_encap_tmpl *encap = x->encap; | |
31a4ab93 | 225 | struct udphdr *uh = (void *)(skb->nh.raw + ihl); |
752c1f4c HX |
226 | |
227 | /* | |
228 | * 1) if the NAT-T peer's IP or port changed then | |
229 | * advertize the change to the keying daemon. | |
230 | * This is an inbound SA, so just compare | |
231 | * SRC ports. | |
232 | */ | |
233 | if (iph->saddr != x->props.saddr.a4 || | |
234 | uh->source != encap->encap_sport) { | |
235 | xfrm_address_t ipaddr; | |
236 | ||
237 | ipaddr.a4 = iph->saddr; | |
238 | km_new_mapping(x, &ipaddr, uh->source); | |
e905a9ed | 239 | |
752c1f4c HX |
240 | /* XXX: perhaps add an extra |
241 | * policy check here, to see | |
242 | * if we should allow or | |
243 | * reject a packet from a | |
244 | * different source | |
245 | * address/port. | |
246 | */ | |
1da177e4 | 247 | } |
e905a9ed | 248 | |
752c1f4c HX |
249 | /* |
250 | * 2) ignore UDP/TCP checksums in case | |
251 | * of NAT-T in Transport Mode, or | |
252 | * perform other post-processing fixes | |
253 | * as per draft-ietf-ipsec-udp-encaps-06, | |
254 | * section 3.1.2 | |
255 | */ | |
0a69452c DB |
256 | if (x->props.mode == XFRM_MODE_TRANSPORT || |
257 | x->props.mode == XFRM_MODE_BEET) | |
752c1f4c | 258 | skb->ip_summed = CHECKSUM_UNNECESSARY; |
1da177e4 LT |
259 | } |
260 | ||
4bf05ece HX |
261 | iph->protocol = nexthdr[1]; |
262 | pskb_trim(skb, skb->len - alen - padlen - 2); | |
31a4ab93 | 263 | skb->h.raw = __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen) - ihl; |
4bf05ece | 264 | |
1da177e4 LT |
265 | return 0; |
266 | ||
267 | out: | |
268 | return -EINVAL; | |
269 | } | |
270 | ||
1da177e4 LT |
271 | static u32 esp4_get_max_size(struct xfrm_state *x, int mtu) |
272 | { | |
273 | struct esp_data *esp = x->data; | |
6b7326c8 | 274 | u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4); |
0a69452c DB |
275 | int enclen = 0; |
276 | ||
277 | switch (x->props.mode) { | |
278 | case XFRM_MODE_TUNNEL: | |
279 | mtu = ALIGN(mtu +2, blksize); | |
280 | break; | |
281 | default: | |
282 | case XFRM_MODE_TRANSPORT: | |
283 | /* The worst case */ | |
d4875b04 | 284 | mtu = ALIGN(mtu + 2, 4) + blksize - 4; |
0a69452c DB |
285 | break; |
286 | case XFRM_MODE_BEET: | |
e905a9ed | 287 | /* The worst case. */ |
0a69452c DB |
288 | enclen = IPV4_BEET_PHMAXLEN; |
289 | mtu = ALIGN(mtu + enclen + 2, blksize); | |
290 | break; | |
1da177e4 | 291 | } |
0a69452c | 292 | |
1da177e4 | 293 | if (esp->conf.padlen) |
a02a6422 | 294 | mtu = ALIGN(mtu, esp->conf.padlen); |
1da177e4 | 295 | |
0a69452c | 296 | return mtu + x->props.header_len + esp->auth.icv_trunc_len - enclen; |
1da177e4 LT |
297 | } |
298 | ||
299 | static void esp4_err(struct sk_buff *skb, u32 info) | |
300 | { | |
301 | struct iphdr *iph = (struct iphdr*)skb->data; | |
302 | struct ip_esp_hdr *esph = (struct ip_esp_hdr*)(skb->data+(iph->ihl<<2)); | |
303 | struct xfrm_state *x; | |
304 | ||
305 | if (skb->h.icmph->type != ICMP_DEST_UNREACH || | |
306 | skb->h.icmph->code != ICMP_FRAG_NEEDED) | |
307 | return; | |
308 | ||
309 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET); | |
310 | if (!x) | |
311 | return; | |
64ce2073 PM |
312 | NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n", |
313 | ntohl(esph->spi), ntohl(iph->daddr)); | |
1da177e4 LT |
314 | xfrm_state_put(x); |
315 | } | |
316 | ||
317 | static void esp_destroy(struct xfrm_state *x) | |
318 | { | |
319 | struct esp_data *esp = x->data; | |
320 | ||
321 | if (!esp) | |
322 | return; | |
323 | ||
6b7326c8 | 324 | crypto_free_blkcipher(esp->conf.tfm); |
573dbd95 JJ |
325 | esp->conf.tfm = NULL; |
326 | kfree(esp->conf.ivec); | |
327 | esp->conf.ivec = NULL; | |
07d4ee58 | 328 | crypto_free_hash(esp->auth.tfm); |
573dbd95 JJ |
329 | esp->auth.tfm = NULL; |
330 | kfree(esp->auth.work_icv); | |
331 | esp->auth.work_icv = NULL; | |
1da177e4 LT |
332 | kfree(esp); |
333 | } | |
334 | ||
72cb6962 | 335 | static int esp_init_state(struct xfrm_state *x) |
1da177e4 LT |
336 | { |
337 | struct esp_data *esp = NULL; | |
6b7326c8 | 338 | struct crypto_blkcipher *tfm; |
1da177e4 LT |
339 | |
340 | /* null auth and encryption can have zero length keys */ | |
341 | if (x->aalg) { | |
342 | if (x->aalg->alg_key_len > 512) | |
343 | goto error; | |
344 | } | |
345 | if (x->ealg == NULL) | |
346 | goto error; | |
347 | ||
0da974f4 | 348 | esp = kzalloc(sizeof(*esp), GFP_KERNEL); |
1da177e4 LT |
349 | if (esp == NULL) |
350 | return -ENOMEM; | |
351 | ||
1da177e4 LT |
352 | if (x->aalg) { |
353 | struct xfrm_algo_desc *aalg_desc; | |
07d4ee58 | 354 | struct crypto_hash *hash; |
1da177e4 LT |
355 | |
356 | esp->auth.key = x->aalg->alg_key; | |
357 | esp->auth.key_len = (x->aalg->alg_key_len+7)/8; | |
07d4ee58 HX |
358 | hash = crypto_alloc_hash(x->aalg->alg_name, 0, |
359 | CRYPTO_ALG_ASYNC); | |
360 | if (IS_ERR(hash)) | |
361 | goto error; | |
362 | ||
363 | esp->auth.tfm = hash; | |
364 | if (crypto_hash_setkey(hash, esp->auth.key, esp->auth.key_len)) | |
1da177e4 | 365 | goto error; |
1da177e4 LT |
366 | |
367 | aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); | |
368 | BUG_ON(!aalg_desc); | |
369 | ||
370 | if (aalg_desc->uinfo.auth.icv_fullbits/8 != | |
07d4ee58 | 371 | crypto_hash_digestsize(hash)) { |
64ce2073 PM |
372 | NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n", |
373 | x->aalg->alg_name, | |
07d4ee58 | 374 | crypto_hash_digestsize(hash), |
64ce2073 | 375 | aalg_desc->uinfo.auth.icv_fullbits/8); |
1da177e4 LT |
376 | goto error; |
377 | } | |
378 | ||
379 | esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8; | |
380 | esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8; | |
381 | ||
382 | esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL); | |
383 | if (!esp->auth.work_icv) | |
384 | goto error; | |
385 | } | |
386 | esp->conf.key = x->ealg->alg_key; | |
387 | esp->conf.key_len = (x->ealg->alg_key_len+7)/8; | |
6b7326c8 HX |
388 | tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC); |
389 | if (IS_ERR(tfm)) | |
1da177e4 | 390 | goto error; |
6b7326c8 HX |
391 | esp->conf.tfm = tfm; |
392 | esp->conf.ivlen = crypto_blkcipher_ivsize(tfm); | |
1da177e4 LT |
393 | esp->conf.padlen = 0; |
394 | if (esp->conf.ivlen) { | |
395 | esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL); | |
396 | if (unlikely(esp->conf.ivec == NULL)) | |
397 | goto error; | |
e4bec827 | 398 | esp->conf.ivinitted = 0; |
1da177e4 | 399 | } |
6b7326c8 | 400 | if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len)) |
1da177e4 LT |
401 | goto error; |
402 | x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen; | |
7e49e6de | 403 | if (x->props.mode == XFRM_MODE_TUNNEL) |
1da177e4 LT |
404 | x->props.header_len += sizeof(struct iphdr); |
405 | if (x->encap) { | |
406 | struct xfrm_encap_tmpl *encap = x->encap; | |
407 | ||
408 | switch (encap->encap_type) { | |
409 | default: | |
410 | goto error; | |
411 | case UDP_ENCAP_ESPINUDP: | |
412 | x->props.header_len += sizeof(struct udphdr); | |
413 | break; | |
414 | case UDP_ENCAP_ESPINUDP_NON_IKE: | |
415 | x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); | |
416 | break; | |
417 | } | |
418 | } | |
419 | x->data = esp; | |
420 | x->props.trailer_len = esp4_get_max_size(x, 0) - x->props.header_len; | |
421 | return 0; | |
422 | ||
423 | error: | |
424 | x->data = esp; | |
425 | esp_destroy(x); | |
426 | x->data = NULL; | |
427 | return -EINVAL; | |
428 | } | |
429 | ||
430 | static struct xfrm_type esp_type = | |
431 | { | |
432 | .description = "ESP4", | |
433 | .owner = THIS_MODULE, | |
434 | .proto = IPPROTO_ESP, | |
435 | .init_state = esp_init_state, | |
436 | .destructor = esp_destroy, | |
437 | .get_max_size = esp4_get_max_size, | |
438 | .input = esp_input, | |
1da177e4 LT |
439 | .output = esp_output |
440 | }; | |
441 | ||
442 | static struct net_protocol esp4_protocol = { | |
443 | .handler = xfrm4_rcv, | |
444 | .err_handler = esp4_err, | |
445 | .no_policy = 1, | |
446 | }; | |
447 | ||
448 | static int __init esp4_init(void) | |
449 | { | |
1da177e4 LT |
450 | if (xfrm_register_type(&esp_type, AF_INET) < 0) { |
451 | printk(KERN_INFO "ip esp init: can't add xfrm type\n"); | |
452 | return -EAGAIN; | |
453 | } | |
454 | if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) { | |
455 | printk(KERN_INFO "ip esp init: can't add protocol\n"); | |
456 | xfrm_unregister_type(&esp_type, AF_INET); | |
457 | return -EAGAIN; | |
458 | } | |
459 | return 0; | |
460 | } | |
461 | ||
462 | static void __exit esp4_fini(void) | |
463 | { | |
464 | if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0) | |
465 | printk(KERN_INFO "ip esp close: can't remove protocol\n"); | |
466 | if (xfrm_unregister_type(&esp_type, AF_INET) < 0) | |
467 | printk(KERN_INFO "ip esp close: can't remove xfrm type\n"); | |
468 | } | |
469 | ||
470 | module_init(esp4_init); | |
471 | module_exit(esp4_fini); | |
472 | MODULE_LICENSE("GPL"); |