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; | |
27a884dc | 24 | u8 *tail; |
1da177e4 LT |
25 | int blksize; |
26 | int clen; | |
27 | int alen; | |
28 | int nfrags; | |
29 | ||
30 | /* Strip IP+ESP header. */ | |
ea2ae17d | 31 | __skb_pull(skb, skb_transport_offset(skb)); |
1da177e4 LT |
32 | /* Now skb is pure payload to encrypt */ |
33 | ||
34 | err = -ENOMEM; | |
35 | ||
36 | /* Round to block size */ | |
37 | clen = skb->len; | |
38 | ||
39 | esp = x->data; | |
40 | alen = esp->auth.icv_trunc_len; | |
41 | tfm = esp->conf.tfm; | |
6b7326c8 HX |
42 | desc.tfm = tfm; |
43 | desc.flags = 0; | |
44 | blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4); | |
a02a6422 | 45 | clen = ALIGN(clen + 2, blksize); |
1da177e4 | 46 | if (esp->conf.padlen) |
a02a6422 | 47 | clen = ALIGN(clen, esp->conf.padlen); |
1da177e4 LT |
48 | |
49 | if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) | |
50 | goto error; | |
51 | ||
52 | /* Fill padding... */ | |
27a884dc | 53 | tail = skb_tail_pointer(trailer); |
1da177e4 LT |
54 | do { |
55 | int i; | |
56 | for (i=0; i<clen-skb->len - 2; i++) | |
27a884dc | 57 | tail[i] = i + 1; |
1da177e4 | 58 | } while (0); |
27a884dc | 59 | tail[clen - skb->len - 2] = (clen - skb->len) - 2; |
1da177e4 LT |
60 | pskb_put(skb, trailer, clen - skb->len); |
61 | ||
d56f90a7 | 62 | __skb_push(skb, skb->data - skb_network_header(skb)); |
eddc9ec5 | 63 | top_iph = ip_hdr(skb); |
d56f90a7 ACM |
64 | esph = (struct ip_esp_hdr *)(skb_network_header(skb) + |
65 | top_iph->ihl * 4); | |
1da177e4 | 66 | top_iph->tot_len = htons(skb->len + alen); |
55792258 | 67 | *(skb_tail_pointer(trailer) - 1) = top_iph->protocol; |
1da177e4 LT |
68 | |
69 | /* this is non-NULL only with UDP Encapsulation */ | |
70 | if (x->encap) { | |
71 | struct xfrm_encap_tmpl *encap = x->encap; | |
72 | struct udphdr *uh; | |
d5a0a1e3 | 73 | __be32 *udpdata32; |
1da177e4 LT |
74 | |
75 | uh = (struct udphdr *)esph; | |
76 | uh->source = encap->encap_sport; | |
77 | uh->dest = encap->encap_dport; | |
78 | uh->len = htons(skb->len + alen - top_iph->ihl*4); | |
79 | uh->check = 0; | |
80 | ||
81 | switch (encap->encap_type) { | |
82 | default: | |
83 | case UDP_ENCAP_ESPINUDP: | |
84 | esph = (struct ip_esp_hdr *)(uh + 1); | |
85 | break; | |
86 | case UDP_ENCAP_ESPINUDP_NON_IKE: | |
d5a0a1e3 | 87 | udpdata32 = (__be32 *)(uh + 1); |
1da177e4 LT |
88 | udpdata32[0] = udpdata32[1] = 0; |
89 | esph = (struct ip_esp_hdr *)(udpdata32 + 2); | |
90 | break; | |
91 | } | |
92 | ||
93 | top_iph->protocol = IPPROTO_UDP; | |
94 | } else | |
95 | top_iph->protocol = IPPROTO_ESP; | |
96 | ||
97 | esph->spi = x->id.spi; | |
98 | esph->seq_no = htonl(++x->replay.oseq); | |
9500e8a8 | 99 | xfrm_aevent_doreplay(x); |
1da177e4 | 100 | |
e4bec827 DM |
101 | if (esp->conf.ivlen) { |
102 | if (unlikely(!esp->conf.ivinitted)) { | |
103 | get_random_bytes(esp->conf.ivec, esp->conf.ivlen); | |
104 | esp->conf.ivinitted = 1; | |
105 | } | |
6b7326c8 | 106 | crypto_blkcipher_set_iv(tfm, esp->conf.ivec, esp->conf.ivlen); |
e4bec827 | 107 | } |
1da177e4 LT |
108 | |
109 | do { | |
110 | struct scatterlist *sg = &esp->sgbuf[0]; | |
111 | ||
112 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { | |
113 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); | |
114 | if (!sg) | |
115 | goto error; | |
116 | } | |
117 | skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen); | |
6b7326c8 | 118 | err = crypto_blkcipher_encrypt(&desc, sg, sg, clen); |
1da177e4 LT |
119 | if (unlikely(sg != &esp->sgbuf[0])) |
120 | kfree(sg); | |
121 | } while (0); | |
122 | ||
6b7326c8 HX |
123 | if (unlikely(err)) |
124 | goto error; | |
125 | ||
1da177e4 | 126 | if (esp->conf.ivlen) { |
6b7326c8 HX |
127 | memcpy(esph->enc_data, esp->conf.ivec, esp->conf.ivlen); |
128 | crypto_blkcipher_get_iv(tfm, esp->conf.ivec, esp->conf.ivlen); | |
1da177e4 LT |
129 | } |
130 | ||
131 | if (esp->auth.icv_full_len) { | |
07d4ee58 HX |
132 | err = esp_mac_digest(esp, skb, (u8 *)esph - skb->data, |
133 | sizeof(*esph) + esp->conf.ivlen + clen); | |
134 | memcpy(pskb_put(skb, trailer, alen), esp->auth.work_icv, alen); | |
1da177e4 LT |
135 | } |
136 | ||
137 | ip_send_check(top_iph); | |
138 | ||
1da177e4 LT |
139 | error: |
140 | return err; | |
141 | } | |
142 | ||
143 | /* | |
144 | * Note: detecting truncated vs. non-truncated authentication data is very | |
145 | * expensive, so we only support truncated data, which is the recommended | |
146 | * and common case. | |
147 | */ | |
e695633e | 148 | static int esp_input(struct xfrm_state *x, struct sk_buff *skb) |
1da177e4 LT |
149 | { |
150 | struct iphdr *iph; | |
151 | struct ip_esp_hdr *esph; | |
152 | struct esp_data *esp = x->data; | |
6b7326c8 HX |
153 | struct crypto_blkcipher *tfm = esp->conf.tfm; |
154 | struct blkcipher_desc desc = { .tfm = tfm }; | |
1da177e4 | 155 | struct sk_buff *trailer; |
6b7326c8 | 156 | int blksize = ALIGN(crypto_blkcipher_blocksize(tfm), 4); |
1da177e4 LT |
157 | int alen = esp->auth.icv_trunc_len; |
158 | int elen = skb->len - sizeof(struct ip_esp_hdr) - esp->conf.ivlen - alen; | |
159 | int nfrags; | |
31a4ab93 | 160 | int ihl; |
4bf05ece HX |
161 | u8 nexthdr[2]; |
162 | struct scatterlist *sg; | |
4bf05ece | 163 | int padlen; |
6b7326c8 | 164 | int err; |
1da177e4 LT |
165 | |
166 | if (!pskb_may_pull(skb, sizeof(struct ip_esp_hdr))) | |
167 | goto out; | |
168 | ||
169 | if (elen <= 0 || (elen & (blksize-1))) | |
170 | goto out; | |
171 | ||
172 | /* If integrity check is required, do this. */ | |
173 | if (esp->auth.icv_full_len) { | |
07d4ee58 | 174 | u8 sum[alen]; |
1da177e4 | 175 | |
07d4ee58 HX |
176 | err = esp_mac_digest(esp, skb, 0, skb->len - alen); |
177 | if (err) | |
178 | goto out; | |
179 | ||
180 | if (skb_copy_bits(skb, skb->len - alen, sum, alen)) | |
1da177e4 LT |
181 | BUG(); |
182 | ||
07d4ee58 | 183 | if (unlikely(memcmp(esp->auth.work_icv, sum, alen))) { |
1da177e4 LT |
184 | x->stats.integrity_failed++; |
185 | goto out; | |
186 | } | |
187 | } | |
188 | ||
189 | if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) | |
190 | goto out; | |
191 | ||
192 | skb->ip_summed = CHECKSUM_NONE; | |
193 | ||
194 | esph = (struct ip_esp_hdr*)skb->data; | |
1da177e4 LT |
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 | 199 | |
4bf05ece | 200 | sg = &esp->sgbuf[0]; |
1da177e4 | 201 | |
4bf05ece HX |
202 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { |
203 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); | |
204 | if (!sg) | |
205 | goto out; | |
206 | } | |
207 | skb_to_sgvec(skb, sg, sizeof(struct ip_esp_hdr) + esp->conf.ivlen, elen); | |
6b7326c8 | 208 | err = crypto_blkcipher_decrypt(&desc, sg, sg, elen); |
4bf05ece HX |
209 | if (unlikely(sg != &esp->sgbuf[0])) |
210 | kfree(sg); | |
6b7326c8 HX |
211 | if (unlikely(err)) |
212 | return err; | |
1da177e4 | 213 | |
4bf05ece HX |
214 | if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2)) |
215 | BUG(); | |
1da177e4 | 216 | |
4bf05ece HX |
217 | padlen = nexthdr[0]; |
218 | if (padlen+2 >= elen) | |
219 | goto out; | |
1da177e4 | 220 | |
e905a9ed | 221 | /* ... check padding bits here. Silly. :-) */ |
1da177e4 | 222 | |
eddc9ec5 | 223 | iph = ip_hdr(skb); |
31a4ab93 HX |
224 | ihl = iph->ihl * 4; |
225 | ||
752c1f4c HX |
226 | if (x->encap) { |
227 | struct xfrm_encap_tmpl *encap = x->encap; | |
d56f90a7 | 228 | struct udphdr *uh = (void *)(skb_network_header(skb) + ihl); |
752c1f4c HX |
229 | |
230 | /* | |
231 | * 1) if the NAT-T peer's IP or port changed then | |
232 | * advertize the change to the keying daemon. | |
233 | * This is an inbound SA, so just compare | |
234 | * SRC ports. | |
235 | */ | |
236 | if (iph->saddr != x->props.saddr.a4 || | |
237 | uh->source != encap->encap_sport) { | |
238 | xfrm_address_t ipaddr; | |
239 | ||
240 | ipaddr.a4 = iph->saddr; | |
241 | km_new_mapping(x, &ipaddr, uh->source); | |
e905a9ed | 242 | |
752c1f4c HX |
243 | /* XXX: perhaps add an extra |
244 | * policy check here, to see | |
245 | * if we should allow or | |
246 | * reject a packet from a | |
247 | * different source | |
248 | * address/port. | |
249 | */ | |
1da177e4 | 250 | } |
e905a9ed | 251 | |
752c1f4c HX |
252 | /* |
253 | * 2) ignore UDP/TCP checksums in case | |
254 | * of NAT-T in Transport Mode, or | |
255 | * perform other post-processing fixes | |
256 | * as per draft-ietf-ipsec-udp-encaps-06, | |
257 | * section 3.1.2 | |
258 | */ | |
0a69452c DB |
259 | if (x->props.mode == XFRM_MODE_TRANSPORT || |
260 | x->props.mode == XFRM_MODE_BEET) | |
752c1f4c | 261 | skb->ip_summed = CHECKSUM_UNNECESSARY; |
1da177e4 LT |
262 | } |
263 | ||
4bf05ece HX |
264 | iph->protocol = nexthdr[1]; |
265 | pskb_trim(skb, skb->len - alen - padlen - 2); | |
967b05f6 ACM |
266 | __skb_pull(skb, sizeof(*esph) + esp->conf.ivlen); |
267 | skb_set_transport_header(skb, -ihl); | |
4bf05ece | 268 | |
1da177e4 LT |
269 | return 0; |
270 | ||
271 | out: | |
272 | return -EINVAL; | |
273 | } | |
274 | ||
1da177e4 LT |
275 | static u32 esp4_get_max_size(struct xfrm_state *x, int mtu) |
276 | { | |
277 | struct esp_data *esp = x->data; | |
6b7326c8 | 278 | u32 blksize = ALIGN(crypto_blkcipher_blocksize(esp->conf.tfm), 4); |
0a69452c DB |
279 | int enclen = 0; |
280 | ||
281 | switch (x->props.mode) { | |
282 | case XFRM_MODE_TUNNEL: | |
283 | mtu = ALIGN(mtu +2, blksize); | |
284 | break; | |
285 | default: | |
286 | case XFRM_MODE_TRANSPORT: | |
287 | /* The worst case */ | |
d4875b04 | 288 | mtu = ALIGN(mtu + 2, 4) + blksize - 4; |
0a69452c DB |
289 | break; |
290 | case XFRM_MODE_BEET: | |
e905a9ed | 291 | /* The worst case. */ |
0a69452c DB |
292 | enclen = IPV4_BEET_PHMAXLEN; |
293 | mtu = ALIGN(mtu + enclen + 2, blksize); | |
294 | break; | |
1da177e4 | 295 | } |
0a69452c | 296 | |
1da177e4 | 297 | if (esp->conf.padlen) |
a02a6422 | 298 | mtu = ALIGN(mtu, esp->conf.padlen); |
1da177e4 | 299 | |
0a69452c | 300 | return mtu + x->props.header_len + esp->auth.icv_trunc_len - enclen; |
1da177e4 LT |
301 | } |
302 | ||
303 | static void esp4_err(struct sk_buff *skb, u32 info) | |
304 | { | |
305 | struct iphdr *iph = (struct iphdr*)skb->data; | |
306 | struct ip_esp_hdr *esph = (struct ip_esp_hdr*)(skb->data+(iph->ihl<<2)); | |
307 | struct xfrm_state *x; | |
308 | ||
88c7664f ACM |
309 | if (icmp_hdr(skb)->type != ICMP_DEST_UNREACH || |
310 | icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) | |
1da177e4 LT |
311 | return; |
312 | ||
313 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET); | |
314 | if (!x) | |
315 | return; | |
64ce2073 PM |
316 | NETDEBUG(KERN_DEBUG "pmtu discovery on SA ESP/%08x/%08x\n", |
317 | ntohl(esph->spi), ntohl(iph->daddr)); | |
1da177e4 LT |
318 | xfrm_state_put(x); |
319 | } | |
320 | ||
321 | static void esp_destroy(struct xfrm_state *x) | |
322 | { | |
323 | struct esp_data *esp = x->data; | |
324 | ||
325 | if (!esp) | |
326 | return; | |
327 | ||
6b7326c8 | 328 | crypto_free_blkcipher(esp->conf.tfm); |
573dbd95 JJ |
329 | esp->conf.tfm = NULL; |
330 | kfree(esp->conf.ivec); | |
331 | esp->conf.ivec = NULL; | |
07d4ee58 | 332 | crypto_free_hash(esp->auth.tfm); |
573dbd95 JJ |
333 | esp->auth.tfm = NULL; |
334 | kfree(esp->auth.work_icv); | |
335 | esp->auth.work_icv = NULL; | |
1da177e4 LT |
336 | kfree(esp); |
337 | } | |
338 | ||
72cb6962 | 339 | static int esp_init_state(struct xfrm_state *x) |
1da177e4 LT |
340 | { |
341 | struct esp_data *esp = NULL; | |
6b7326c8 | 342 | struct crypto_blkcipher *tfm; |
1da177e4 LT |
343 | |
344 | /* null auth and encryption can have zero length keys */ | |
345 | if (x->aalg) { | |
346 | if (x->aalg->alg_key_len > 512) | |
347 | goto error; | |
348 | } | |
349 | if (x->ealg == NULL) | |
350 | goto error; | |
351 | ||
0da974f4 | 352 | esp = kzalloc(sizeof(*esp), GFP_KERNEL); |
1da177e4 LT |
353 | if (esp == NULL) |
354 | return -ENOMEM; | |
355 | ||
1da177e4 LT |
356 | if (x->aalg) { |
357 | struct xfrm_algo_desc *aalg_desc; | |
07d4ee58 | 358 | struct crypto_hash *hash; |
1da177e4 LT |
359 | |
360 | esp->auth.key = x->aalg->alg_key; | |
361 | esp->auth.key_len = (x->aalg->alg_key_len+7)/8; | |
07d4ee58 HX |
362 | hash = crypto_alloc_hash(x->aalg->alg_name, 0, |
363 | CRYPTO_ALG_ASYNC); | |
364 | if (IS_ERR(hash)) | |
365 | goto error; | |
366 | ||
367 | esp->auth.tfm = hash; | |
368 | if (crypto_hash_setkey(hash, esp->auth.key, esp->auth.key_len)) | |
1da177e4 | 369 | goto error; |
1da177e4 LT |
370 | |
371 | aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0); | |
372 | BUG_ON(!aalg_desc); | |
373 | ||
374 | if (aalg_desc->uinfo.auth.icv_fullbits/8 != | |
07d4ee58 | 375 | crypto_hash_digestsize(hash)) { |
64ce2073 PM |
376 | NETDEBUG(KERN_INFO "ESP: %s digestsize %u != %hu\n", |
377 | x->aalg->alg_name, | |
07d4ee58 | 378 | crypto_hash_digestsize(hash), |
64ce2073 | 379 | aalg_desc->uinfo.auth.icv_fullbits/8); |
1da177e4 LT |
380 | goto error; |
381 | } | |
382 | ||
383 | esp->auth.icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8; | |
384 | esp->auth.icv_trunc_len = aalg_desc->uinfo.auth.icv_truncbits/8; | |
385 | ||
386 | esp->auth.work_icv = kmalloc(esp->auth.icv_full_len, GFP_KERNEL); | |
387 | if (!esp->auth.work_icv) | |
388 | goto error; | |
389 | } | |
390 | esp->conf.key = x->ealg->alg_key; | |
391 | esp->conf.key_len = (x->ealg->alg_key_len+7)/8; | |
6b7326c8 HX |
392 | tfm = crypto_alloc_blkcipher(x->ealg->alg_name, 0, CRYPTO_ALG_ASYNC); |
393 | if (IS_ERR(tfm)) | |
1da177e4 | 394 | goto error; |
6b7326c8 HX |
395 | esp->conf.tfm = tfm; |
396 | esp->conf.ivlen = crypto_blkcipher_ivsize(tfm); | |
1da177e4 LT |
397 | esp->conf.padlen = 0; |
398 | if (esp->conf.ivlen) { | |
399 | esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL); | |
400 | if (unlikely(esp->conf.ivec == NULL)) | |
401 | goto error; | |
e4bec827 | 402 | esp->conf.ivinitted = 0; |
1da177e4 | 403 | } |
6b7326c8 | 404 | if (crypto_blkcipher_setkey(tfm, esp->conf.key, esp->conf.key_len)) |
1da177e4 LT |
405 | goto error; |
406 | x->props.header_len = sizeof(struct ip_esp_hdr) + esp->conf.ivlen; | |
7e49e6de | 407 | if (x->props.mode == XFRM_MODE_TUNNEL) |
1da177e4 LT |
408 | x->props.header_len += sizeof(struct iphdr); |
409 | if (x->encap) { | |
410 | struct xfrm_encap_tmpl *encap = x->encap; | |
411 | ||
412 | switch (encap->encap_type) { | |
413 | default: | |
414 | goto error; | |
415 | case UDP_ENCAP_ESPINUDP: | |
416 | x->props.header_len += sizeof(struct udphdr); | |
417 | break; | |
418 | case UDP_ENCAP_ESPINUDP_NON_IKE: | |
419 | x->props.header_len += sizeof(struct udphdr) + 2 * sizeof(u32); | |
420 | break; | |
421 | } | |
422 | } | |
423 | x->data = esp; | |
424 | x->props.trailer_len = esp4_get_max_size(x, 0) - x->props.header_len; | |
425 | return 0; | |
426 | ||
427 | error: | |
428 | x->data = esp; | |
429 | esp_destroy(x); | |
430 | x->data = NULL; | |
431 | return -EINVAL; | |
432 | } | |
433 | ||
434 | static struct xfrm_type esp_type = | |
435 | { | |
436 | .description = "ESP4", | |
437 | .owner = THIS_MODULE, | |
438 | .proto = IPPROTO_ESP, | |
439 | .init_state = esp_init_state, | |
440 | .destructor = esp_destroy, | |
441 | .get_max_size = esp4_get_max_size, | |
442 | .input = esp_input, | |
1da177e4 LT |
443 | .output = esp_output |
444 | }; | |
445 | ||
446 | static struct net_protocol esp4_protocol = { | |
447 | .handler = xfrm4_rcv, | |
448 | .err_handler = esp4_err, | |
449 | .no_policy = 1, | |
450 | }; | |
451 | ||
452 | static int __init esp4_init(void) | |
453 | { | |
1da177e4 LT |
454 | if (xfrm_register_type(&esp_type, AF_INET) < 0) { |
455 | printk(KERN_INFO "ip esp init: can't add xfrm type\n"); | |
456 | return -EAGAIN; | |
457 | } | |
458 | if (inet_add_protocol(&esp4_protocol, IPPROTO_ESP) < 0) { | |
459 | printk(KERN_INFO "ip esp init: can't add protocol\n"); | |
460 | xfrm_unregister_type(&esp_type, AF_INET); | |
461 | return -EAGAIN; | |
462 | } | |
463 | return 0; | |
464 | } | |
465 | ||
466 | static void __exit esp4_fini(void) | |
467 | { | |
468 | if (inet_del_protocol(&esp4_protocol, IPPROTO_ESP) < 0) | |
469 | printk(KERN_INFO "ip esp close: can't remove protocol\n"); | |
470 | if (xfrm_unregister_type(&esp_type, AF_INET) < 0) | |
471 | printk(KERN_INFO "ip esp close: can't remove xfrm type\n"); | |
472 | } | |
473 | ||
474 | module_init(esp4_init); | |
475 | module_exit(esp4_fini); | |
476 | MODULE_LICENSE("GPL"); |