Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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/config.h> |
| 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> |
| 34 | #include <linux/pfkeyv2.h> |
| 35 | #include <linux/random.h> |
| 36 | #include <net/icmp.h> |
| 37 | #include <net/ipv6.h> |
| 38 | #include <linux/icmpv6.h> |
| 39 | |
| 40 | static int esp6_output(struct xfrm_state *x, struct sk_buff *skb) |
| 41 | { |
| 42 | int err; |
| 43 | int hdr_len; |
| 44 | struct ipv6hdr *top_iph; |
| 45 | struct ipv6_esp_hdr *esph; |
| 46 | struct crypto_tfm *tfm; |
| 47 | struct esp_data *esp; |
| 48 | struct sk_buff *trailer; |
| 49 | int blksize; |
| 50 | int clen; |
| 51 | int alen; |
| 52 | int nfrags; |
| 53 | |
| 54 | esp = x->data; |
| 55 | hdr_len = skb->h.raw - skb->data + |
| 56 | sizeof(*esph) + esp->conf.ivlen; |
| 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; |
| 69 | blksize = (crypto_tfm_alg_blocksize(tfm) + 3) & ~3; |
| 70 | clen = (clen + 2 + blksize-1)&~(blksize-1); |
| 71 | if (esp->conf.padlen) |
| 72 | clen = (clen + esp->conf.padlen-1)&~(esp->conf.padlen-1); |
| 73 | |
| 74 | if ((nfrags = skb_cow_data(skb, clen-skb->len+alen, &trailer)) < 0) { |
| 75 | goto error; |
| 76 | } |
| 77 | |
| 78 | /* Fill padding... */ |
| 79 | do { |
| 80 | int i; |
| 81 | for (i=0; i<clen-skb->len - 2; i++) |
| 82 | *(u8*)(trailer->tail + i) = i+1; |
| 83 | } while (0); |
| 84 | *(u8*)(trailer->tail + clen-skb->len - 2) = (clen - skb->len)-2; |
| 85 | pskb_put(skb, trailer, clen - skb->len); |
| 86 | |
| 87 | top_iph = (struct ipv6hdr *)__skb_push(skb, hdr_len); |
| 88 | esph = (struct ipv6_esp_hdr *)skb->h.raw; |
| 89 | top_iph->payload_len = htons(skb->len + alen - sizeof(*top_iph)); |
| 90 | *(u8*)(trailer->tail - 1) = *skb->nh.raw; |
| 91 | *skb->nh.raw = IPPROTO_ESP; |
| 92 | |
| 93 | esph->spi = x->id.spi; |
| 94 | esph->seq_no = htonl(++x->replay.oseq); |
| 95 | |
| 96 | if (esp->conf.ivlen) |
| 97 | crypto_cipher_set_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm)); |
| 98 | |
| 99 | do { |
| 100 | struct scatterlist *sg = &esp->sgbuf[0]; |
| 101 | |
| 102 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { |
| 103 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); |
| 104 | if (!sg) |
| 105 | goto error; |
| 106 | } |
| 107 | skb_to_sgvec(skb, sg, esph->enc_data+esp->conf.ivlen-skb->data, clen); |
| 108 | crypto_cipher_encrypt(tfm, sg, sg, clen); |
| 109 | if (unlikely(sg != &esp->sgbuf[0])) |
| 110 | kfree(sg); |
| 111 | } while (0); |
| 112 | |
| 113 | if (esp->conf.ivlen) { |
| 114 | memcpy(esph->enc_data, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm)); |
| 115 | crypto_cipher_get_iv(tfm, esp->conf.ivec, crypto_tfm_alg_ivsize(tfm)); |
| 116 | } |
| 117 | |
| 118 | if (esp->auth.icv_full_len) { |
| 119 | esp->auth.icv(esp, skb, (u8*)esph-skb->data, |
| 120 | sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen+clen, trailer->tail); |
| 121 | pskb_put(skb, trailer, alen); |
| 122 | } |
| 123 | |
| 124 | err = 0; |
| 125 | |
| 126 | error: |
| 127 | return err; |
| 128 | } |
| 129 | |
| 130 | static int esp6_input(struct xfrm_state *x, struct xfrm_decap_state *decap, struct sk_buff *skb) |
| 131 | { |
| 132 | struct ipv6hdr *iph; |
| 133 | struct ipv6_esp_hdr *esph; |
| 134 | struct esp_data *esp = x->data; |
| 135 | struct sk_buff *trailer; |
| 136 | int blksize = crypto_tfm_alg_blocksize(esp->conf.tfm); |
| 137 | int alen = esp->auth.icv_trunc_len; |
| 138 | int elen = skb->len - sizeof(struct ipv6_esp_hdr) - esp->conf.ivlen - alen; |
| 139 | |
| 140 | int hdr_len = skb->h.raw - skb->nh.raw; |
| 141 | int nfrags; |
| 142 | unsigned char *tmp_hdr = NULL; |
| 143 | int ret = 0; |
| 144 | |
| 145 | if (!pskb_may_pull(skb, sizeof(struct ipv6_esp_hdr))) { |
| 146 | ret = -EINVAL; |
| 147 | goto out_nofree; |
| 148 | } |
| 149 | |
| 150 | if (elen <= 0 || (elen & (blksize-1))) { |
| 151 | ret = -EINVAL; |
| 152 | goto out_nofree; |
| 153 | } |
| 154 | |
| 155 | tmp_hdr = kmalloc(hdr_len, GFP_ATOMIC); |
| 156 | if (!tmp_hdr) { |
| 157 | ret = -ENOMEM; |
| 158 | goto out_nofree; |
| 159 | } |
| 160 | memcpy(tmp_hdr, skb->nh.raw, hdr_len); |
| 161 | |
| 162 | /* If integrity check is required, do this. */ |
| 163 | if (esp->auth.icv_full_len) { |
| 164 | u8 sum[esp->auth.icv_full_len]; |
| 165 | u8 sum1[alen]; |
| 166 | |
| 167 | esp->auth.icv(esp, skb, 0, skb->len-alen, sum); |
| 168 | |
| 169 | if (skb_copy_bits(skb, skb->len-alen, sum1, alen)) |
| 170 | BUG(); |
| 171 | |
| 172 | if (unlikely(memcmp(sum, sum1, alen))) { |
| 173 | x->stats.integrity_failed++; |
| 174 | ret = -EINVAL; |
| 175 | goto out; |
| 176 | } |
| 177 | } |
| 178 | |
| 179 | if ((nfrags = skb_cow_data(skb, 0, &trailer)) < 0) { |
| 180 | ret = -EINVAL; |
| 181 | goto out; |
| 182 | } |
| 183 | |
| 184 | skb->ip_summed = CHECKSUM_NONE; |
| 185 | |
| 186 | esph = (struct ipv6_esp_hdr*)skb->data; |
| 187 | iph = skb->nh.ipv6h; |
| 188 | |
| 189 | /* Get ivec. This can be wrong, check against another impls. */ |
| 190 | if (esp->conf.ivlen) |
| 191 | crypto_cipher_set_iv(esp->conf.tfm, esph->enc_data, crypto_tfm_alg_ivsize(esp->conf.tfm)); |
| 192 | |
| 193 | { |
| 194 | u8 nexthdr[2]; |
| 195 | struct scatterlist *sg = &esp->sgbuf[0]; |
| 196 | u8 padlen; |
| 197 | |
| 198 | if (unlikely(nfrags > ESP_NUM_FAST_SG)) { |
| 199 | sg = kmalloc(sizeof(struct scatterlist)*nfrags, GFP_ATOMIC); |
| 200 | if (!sg) { |
| 201 | ret = -ENOMEM; |
| 202 | goto out; |
| 203 | } |
| 204 | } |
| 205 | skb_to_sgvec(skb, sg, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen, elen); |
| 206 | crypto_cipher_decrypt(esp->conf.tfm, sg, sg, elen); |
| 207 | if (unlikely(sg != &esp->sgbuf[0])) |
| 208 | kfree(sg); |
| 209 | |
| 210 | if (skb_copy_bits(skb, skb->len-alen-2, nexthdr, 2)) |
| 211 | BUG(); |
| 212 | |
| 213 | padlen = nexthdr[0]; |
| 214 | if (padlen+2 >= elen) { |
| 215 | LIMIT_NETDEBUG( |
| 216 | printk(KERN_WARNING "ipsec esp packet is garbage padlen=%d, elen=%d\n", padlen+2, elen)); |
| 217 | ret = -EINVAL; |
| 218 | goto out; |
| 219 | } |
| 220 | /* ... check padding bits here. Silly. :-) */ |
| 221 | |
| 222 | pskb_trim(skb, skb->len - alen - padlen - 2); |
| 223 | skb->h.raw = skb_pull(skb, sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen); |
| 224 | skb->nh.raw += sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen; |
| 225 | memcpy(skb->nh.raw, tmp_hdr, hdr_len); |
| 226 | skb->nh.ipv6h->payload_len = htons(skb->len - sizeof(struct ipv6hdr)); |
| 227 | ret = nexthdr[1]; |
| 228 | } |
| 229 | |
| 230 | out: |
| 231 | kfree(tmp_hdr); |
| 232 | out_nofree: |
| 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; |
| 239 | u32 blksize = crypto_tfm_alg_blocksize(esp->conf.tfm); |
| 240 | |
| 241 | if (x->props.mode) { |
| 242 | mtu = (mtu + 2 + blksize-1)&~(blksize-1); |
| 243 | } else { |
| 244 | /* The worst case. */ |
| 245 | mtu += 2 + blksize; |
| 246 | } |
| 247 | if (esp->conf.padlen) |
| 248 | mtu = (mtu + esp->conf.padlen-1)&~(esp->conf.padlen-1); |
| 249 | |
| 250 | return mtu + x->props.header_len + esp->auth.icv_full_len; |
| 251 | } |
| 252 | |
| 253 | static void esp6_err(struct sk_buff *skb, struct inet6_skb_parm *opt, |
| 254 | int type, int code, int offset, __u32 info) |
| 255 | { |
| 256 | struct ipv6hdr *iph = (struct ipv6hdr*)skb->data; |
| 257 | struct ipv6_esp_hdr *esph = (struct ipv6_esp_hdr*)(skb->data+offset); |
| 258 | struct xfrm_state *x; |
| 259 | |
| 260 | if (type != ICMPV6_DEST_UNREACH && |
| 261 | type != ICMPV6_PKT_TOOBIG) |
| 262 | return; |
| 263 | |
| 264 | x = xfrm_state_lookup((xfrm_address_t *)&iph->daddr, esph->spi, IPPROTO_ESP, AF_INET6); |
| 265 | if (!x) |
| 266 | return; |
| 267 | printk(KERN_DEBUG "pmtu discovery on SA ESP/%08x/" |
| 268 | "%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x\n", |
| 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 | |
| 280 | if (esp->conf.tfm) { |
| 281 | crypto_free_tfm(esp->conf.tfm); |
| 282 | esp->conf.tfm = NULL; |
| 283 | } |
| 284 | if (esp->conf.ivec) { |
| 285 | kfree(esp->conf.ivec); |
| 286 | esp->conf.ivec = NULL; |
| 287 | } |
| 288 | if (esp->auth.tfm) { |
| 289 | crypto_free_tfm(esp->auth.tfm); |
| 290 | esp->auth.tfm = NULL; |
| 291 | } |
| 292 | if (esp->auth.work_icv) { |
| 293 | kfree(esp->auth.work_icv); |
| 294 | esp->auth.work_icv = NULL; |
| 295 | } |
| 296 | kfree(esp); |
| 297 | } |
| 298 | |
| 299 | static int esp6_init_state(struct xfrm_state *x, void *args) |
| 300 | { |
| 301 | struct esp_data *esp = NULL; |
| 302 | |
| 303 | /* null auth and encryption can have zero length keys */ |
| 304 | if (x->aalg) { |
| 305 | if (x->aalg->alg_key_len > 512) |
| 306 | goto error; |
| 307 | } |
| 308 | if (x->ealg == NULL) |
| 309 | goto error; |
| 310 | |
| 311 | if (x->encap) |
| 312 | goto error; |
| 313 | |
| 314 | esp = kmalloc(sizeof(*esp), GFP_KERNEL); |
| 315 | if (esp == NULL) |
| 316 | return -ENOMEM; |
| 317 | |
| 318 | memset(esp, 0, sizeof(*esp)); |
| 319 | |
| 320 | if (x->aalg) { |
| 321 | struct xfrm_algo_desc *aalg_desc; |
| 322 | |
| 323 | esp->auth.key = x->aalg->alg_key; |
| 324 | esp->auth.key_len = (x->aalg->alg_key_len+7)/8; |
| 325 | esp->auth.tfm = crypto_alloc_tfm(x->aalg->alg_name, 0); |
| 326 | if (esp->auth.tfm == NULL) |
| 327 | goto error; |
| 328 | esp->auth.icv = esp_hmac_digest; |
| 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 != |
| 334 | crypto_tfm_alg_digestsize(esp->auth.tfm)) { |
| 335 | printk(KERN_INFO "ESP: %s digestsize %u != %hu\n", |
| 336 | x->aalg->alg_name, |
| 337 | crypto_tfm_alg_digestsize(esp->auth.tfm), |
| 338 | aalg_desc->uinfo.auth.icv_fullbits/8); |
| 339 | goto error; |
| 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; |
| 351 | if (x->props.ealgo == SADB_EALG_NULL) |
| 352 | esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_ECB); |
| 353 | else |
| 354 | esp->conf.tfm = crypto_alloc_tfm(x->ealg->alg_name, CRYPTO_TFM_MODE_CBC); |
| 355 | if (esp->conf.tfm == NULL) |
| 356 | goto error; |
| 357 | esp->conf.ivlen = crypto_tfm_alg_ivsize(esp->conf.tfm); |
| 358 | esp->conf.padlen = 0; |
| 359 | if (esp->conf.ivlen) { |
| 360 | esp->conf.ivec = kmalloc(esp->conf.ivlen, GFP_KERNEL); |
| 361 | if (unlikely(esp->conf.ivec == NULL)) |
| 362 | goto error; |
| 363 | get_random_bytes(esp->conf.ivec, esp->conf.ivlen); |
| 364 | } |
| 365 | if (crypto_cipher_setkey(esp->conf.tfm, esp->conf.key, esp->conf.key_len)) |
| 366 | goto error; |
| 367 | x->props.header_len = sizeof(struct ipv6_esp_hdr) + esp->conf.ivlen; |
| 368 | if (x->props.mode) |
| 369 | x->props.header_len += sizeof(struct ipv6hdr); |
| 370 | x->data = esp; |
| 371 | return 0; |
| 372 | |
| 373 | error: |
| 374 | x->data = esp; |
| 375 | esp6_destroy(x); |
| 376 | x->data = NULL; |
| 377 | return -EINVAL; |
| 378 | } |
| 379 | |
| 380 | static struct xfrm_type esp6_type = |
| 381 | { |
| 382 | .description = "ESP6", |
| 383 | .owner = THIS_MODULE, |
| 384 | .proto = IPPROTO_ESP, |
| 385 | .init_state = esp6_init_state, |
| 386 | .destructor = esp6_destroy, |
| 387 | .get_max_size = esp6_get_max_size, |
| 388 | .input = esp6_input, |
| 389 | .output = esp6_output |
| 390 | }; |
| 391 | |
| 392 | static struct inet6_protocol esp6_protocol = { |
| 393 | .handler = xfrm6_rcv, |
| 394 | .err_handler = esp6_err, |
| 395 | .flags = INET6_PROTO_NOPOLICY, |
| 396 | }; |
| 397 | |
| 398 | static int __init esp6_init(void) |
| 399 | { |
| 400 | if (xfrm_register_type(&esp6_type, AF_INET6) < 0) { |
| 401 | printk(KERN_INFO "ipv6 esp init: can't add xfrm type\n"); |
| 402 | return -EAGAIN; |
| 403 | } |
| 404 | if (inet6_add_protocol(&esp6_protocol, IPPROTO_ESP) < 0) { |
| 405 | printk(KERN_INFO "ipv6 esp init: can't add protocol\n"); |
| 406 | xfrm_unregister_type(&esp6_type, AF_INET6); |
| 407 | return -EAGAIN; |
| 408 | } |
| 409 | |
| 410 | return 0; |
| 411 | } |
| 412 | |
| 413 | static void __exit esp6_fini(void) |
| 414 | { |
| 415 | if (inet6_del_protocol(&esp6_protocol, IPPROTO_ESP) < 0) |
| 416 | printk(KERN_INFO "ipv6 esp close: can't remove protocol\n"); |
| 417 | if (xfrm_unregister_type(&esp6_type, AF_INET6) < 0) |
| 418 | printk(KERN_INFO "ipv6 esp close: can't remove xfrm type\n"); |
| 419 | } |
| 420 | |
| 421 | module_init(esp6_init); |
| 422 | module_exit(esp6_fini); |
| 423 | |
| 424 | MODULE_LICENSE("GPL"); |