crypto/xcbc.c

   1 /*
   2  * Copyright (C)2006 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  * Author:
  19  *      Kazunori Miyazawa <miyazawa@linux-ipv6.org>
  20  */
  21
  22 #include <linux/crypto.h>
  23 #include <linux/err.h>
  24 #include <linux/kernel.h>
  25 #include <linux/mm.h>
  26 #include <linux/rtnetlink.h>
  27 #include <linux/slab.h>
  28 #include <linux/scatterlist.h>
  29 #include "internal.h"
  30
  31 static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
  32                            0x02020202, 0x02020202, 0x02020202, 0x02020202,
  33                            0x03030303, 0x03030303, 0x03030303, 0x03030303};
  34 /*
  35  * +------------------------
  36  * | <parent tfm>
  37  * +------------------------
  38  * | crypto_xcbc_ctx
  39  * +------------------------
  40  * | odds (block size)
  41  * +------------------------
  42  * | prev (block size)
  43  * +------------------------
  44  * | key (block size)
  45  * +------------------------
  46  * | consts (block size * 3)
  47  * +------------------------
  48  */
  49 struct crypto_xcbc_ctx {
  50         struct crypto_tfm *child;
  51         u8 *odds;
  52         u8 *prev;
  53         u8 *key;
  54         u8 *consts;
  55         void (*xor)(u8 *a, const u8 *b, unsigned int bs);
  56         unsigned int keylen;
  57         unsigned int len;
  58 };
  59
  60 static void xor_128(u8 *a, const u8 *b, unsigned int bs)
  61 {
  62         ((u32 *)a)[0] ^= ((u32 *)b)[0];
  63         ((u32 *)a)[1] ^= ((u32 *)b)[1];
  64         ((u32 *)a)[2] ^= ((u32 *)b)[2];
  65         ((u32 *)a)[3] ^= ((u32 *)b)[3];
  66 }
  67
  68 static int _crypto_xcbc_digest_setkey(struct crypto_hash *parent,
  69                                       struct crypto_xcbc_ctx *ctx)
  70 {
  71         int bs = crypto_hash_blocksize(parent);
  72         int err = 0;
  73         u8 key1[bs];
  74
  75         if ((err = crypto_cipher_setkey(ctx->child, ctx->key, ctx->keylen)))
  76             return err;
  77
  78         ctx->child->__crt_alg->cra_cipher.cia_encrypt(ctx->child, key1,
  79                         ctx->consts);
  80
  81         return crypto_cipher_setkey(ctx->child, key1, bs);
  82 }
  83
  84 static int crypto_xcbc_digest_setkey(struct crypto_hash *parent,
  85                                      const u8 *inkey, unsigned int keylen)
  86 {
  87         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
  88
  89         if (keylen != crypto_tfm_alg_blocksize(ctx->child))
  90                 return -EINVAL;
  91
  92         ctx->keylen = keylen;
  93         memcpy(ctx->key, inkey, keylen);
  94         ctx->consts = (u8*)ks;
  95
  96         return _crypto_xcbc_digest_setkey(parent, ctx);
  97 }
  98
  99 static int crypto_xcbc_digest_init(struct hash_desc *pdesc)
 100 {
 101         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(pdesc->tfm);
 102         int bs = crypto_hash_blocksize(pdesc->tfm);
 103
 104         ctx->len = 0;
 105         memset(ctx->odds, 0, bs);
 106         memset(ctx->prev, 0, bs);
 107
 108         return 0;
 109 }
 110
 111 static int crypto_xcbc_digest_update(struct hash_desc *pdesc,
 112                                      struct scatterlist *sg,
 113                                      unsigned int nbytes)
 114 {
 115         struct crypto_hash *parent = pdesc->tfm;
 116         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
 117         struct crypto_tfm *tfm = ctx->child;
 118         int bs = crypto_hash_blocksize(parent);
 119         unsigned int i = 0;
 120
 121         do {
 122
 123                 struct page *pg = sg[i].page;
 124                 unsigned int offset = sg[i].offset;
 125                 unsigned int slen = sg[i].length;
 126
 127                 while (slen > 0) {
 128                         unsigned int len = min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
 129                         char *p = crypto_kmap(pg, 0) + offset;
 130
 131                         /* checking the data can fill the block */
 132                         if ((ctx->len + len) <= bs) {
 133                                 memcpy(ctx->odds + ctx->len, p, len);
 134                                 ctx->len += len;
 135                                 slen -= len;
 136
 137                                 /* checking the rest of the page */
 138                                 if (len + offset >= PAGE_SIZE) {
 139                                         offset = 0;
 140                                         pg++;
 141                                 } else
 142                                         offset += len;
 143
 144                                 crypto_kunmap(p, 0);
 145                                 crypto_yield(tfm->crt_flags);
 146                                 continue;
 147                         }
 148
 149                         /* filling odds with new data and encrypting it */
 150                         memcpy(ctx->odds + ctx->len, p, bs - ctx->len);
 151                         len -= bs - ctx->len;
 152                         p += bs - ctx->len;
 153
 154                         ctx->xor(ctx->prev, ctx->odds, bs);
 155                         tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, ctx->prev, ctx->prev);
 156
 157                         /* clearing the length */
 158                         ctx->len = 0;
 159
 160                         /* encrypting the rest of data */
 161                         while (len > bs) {
 162                                 ctx->xor(ctx->prev, p, bs);
 163                                 tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, ctx->prev, ctx->prev);
 164                                 p += bs;
 165                                 len -= bs;
 166                         }
 167
 168                         /* keeping the surplus of blocksize */
 169                         if (len) {
 170                                 memcpy(ctx->odds, p, len);
 171                                 ctx->len = len;
 172                         }
 173                         crypto_kunmap(p, 0);
 174                         crypto_yield(tfm->crt_flags);
 175                         slen -= min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
 176                         offset = 0;
 177                         pg++;
 178                 }
 179                 nbytes-=sg[i].length;
 180                 i++;
 181         } while (nbytes>0);
 182
 183         return 0;
 184 }
 185
 186 static int crypto_xcbc_digest_final(struct hash_desc *pdesc, u8 *out)
 187 {
 188         struct crypto_hash *parent = pdesc->tfm;
 189         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
 190         struct crypto_tfm *tfm = ctx->child;
 191         int bs = crypto_hash_blocksize(parent);
 192         int err = 0;
 193
 194         if (ctx->len == bs) {
 195                 u8 key2[bs];
 196
 197                 if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
 198                         return err;
 199
 200                 tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, key2, (const u8*)(ctx->consts+bs));
 201
 202                 ctx->xor(ctx->prev, ctx->odds, bs);
 203                 ctx->xor(ctx->prev, key2, bs);
 204                 _crypto_xcbc_digest_setkey(parent, ctx);
 205
 206                 tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, out, ctx->prev);
 207         } else {
 208                 u8 key3[bs];
 209                 unsigned int rlen;
 210                 u8 *p = ctx->odds + ctx->len;
 211                 *p = 0x80;
 212                 p++;
 213
 214                 rlen = bs - ctx->len -1;
 215                 if (rlen)
 216                         memset(p, 0, rlen);
 217
 218                 if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
 219                         return err;
 220
 221                 tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, key3, (const u8*)(ctx->consts+bs*2));
 222
 223                 ctx->xor(ctx->prev, ctx->odds, bs);
 224                 ctx->xor(ctx->prev, key3, bs);
 225
 226                 _crypto_xcbc_digest_setkey(parent, ctx);
 227
 228                 tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, out, ctx->prev);
 229         }
 230
 231         return 0;
 232 }
 233
 234 static int crypto_xcbc_digest(struct hash_desc *pdesc,
 235                   struct scatterlist *sg, unsigned int nbytes, u8 *out)
 236 {
 237         crypto_xcbc_digest_init(pdesc);
 238         crypto_xcbc_digest_update(pdesc, sg, nbytes);
 239         return crypto_xcbc_digest_final(pdesc, out);
 240 }
 241
 242 static int xcbc_init_tfm(struct crypto_tfm *tfm)
 243 {
 244         struct crypto_instance *inst = (void *)tfm->__crt_alg;
 245         struct crypto_spawn *spawn = crypto_instance_ctx(inst);
 246         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
 247         int bs = crypto_hash_blocksize(__crypto_hash_cast(tfm));
 248
 249         tfm = crypto_spawn_tfm(spawn);
 250         if (IS_ERR(tfm))
 251                 return PTR_ERR(tfm);
 252
 253         switch(bs) {
 254         case 16:
 255                 ctx->xor = xor_128;
 256                 break;
 257         default:
 258                 return -EINVAL;
 259         }
 260
 261         ctx->child = crypto_cipher_cast(tfm);
 262         ctx->odds = (u8*)(ctx+1);
 263         ctx->prev = ctx->odds + bs;
 264         ctx->key = ctx->prev + bs;
 265
 266         return 0;
 267 };
 268
 269 static void xcbc_exit_tfm(struct crypto_tfm *tfm)
 270 {
 271         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
 272         crypto_free_cipher(ctx->child);
 273 }
 274
 275 static struct crypto_instance *xcbc_alloc(void *param, unsigned int len)
 276 {
 277         struct crypto_instance *inst;
 278         struct crypto_alg *alg;
 279         alg = crypto_get_attr_alg(param, len, CRYPTO_ALG_TYPE_CIPHER,
 280                                   CRYPTO_ALG_TYPE_HASH_MASK | CRYPTO_ALG_ASYNC);
 281         if (IS_ERR(alg))
 282                 return ERR_PTR(PTR_ERR(alg));
 283
 284         switch(alg->cra_blocksize) {
 285         case 16:
 286                 break;
 287         default:
 288                 return ERR_PTR(PTR_ERR(alg));
 289         }
 290
 291         inst = crypto_alloc_instance("xcbc", alg);
 292         if (IS_ERR(inst))
 293                 goto out_put_alg;
 294
 295         inst->alg.cra_flags = CRYPTO_ALG_TYPE_HASH;
 296         inst->alg.cra_priority = alg->cra_priority;
 297         inst->alg.cra_blocksize = alg->cra_blocksize;
 298         inst->alg.cra_alignmask = alg->cra_alignmask;
 299         inst->alg.cra_type = &crypto_hash_type;
 300
 301         inst->alg.cra_hash.digestsize =
 302                 (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 303                 CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
 304                                        alg->cra_blocksize;
 305         inst->alg.cra_ctxsize = sizeof(struct crypto_xcbc_ctx) +
 306                                 ALIGN(inst->alg.cra_blocksize * 3, sizeof(void *));
 307         inst->alg.cra_init = xcbc_init_tfm;
 308         inst->alg.cra_exit = xcbc_exit_tfm;
 309
 310         inst->alg.cra_hash.init = crypto_xcbc_digest_init;
 311         inst->alg.cra_hash.update = crypto_xcbc_digest_update;
 312         inst->alg.cra_hash.final = crypto_xcbc_digest_final;
 313         inst->alg.cra_hash.digest = crypto_xcbc_digest;
 314         inst->alg.cra_hash.setkey = crypto_xcbc_digest_setkey;
 315
 316 out_put_alg:
 317         crypto_mod_put(alg);
 318         return inst;
 319 }
 320
 321 static void xcbc_free(struct crypto_instance *inst)
 322 {
 323         crypto_drop_spawn(crypto_instance_ctx(inst));
 324         kfree(inst);
 325 }
 326
 327 static struct crypto_template crypto_xcbc_tmpl = {
 328         .name = "xcbc",
 329         .alloc = xcbc_alloc,
 330         .free = xcbc_free,
 331         .module = THIS_MODULE,
 332 };
 333
 334 static int __init crypto_xcbc_module_init(void)
 335 {
 336         return crypto_register_template(&crypto_xcbc_tmpl);
 337 }
 338
 339 static void __exit crypto_xcbc_module_exit(void)
 340 {
 341         crypto_unregister_template(&crypto_xcbc_tmpl);
 342 }
 343
 344 module_init(crypto_xcbc_module_init);
 345 module_exit(crypto_xcbc_module_exit);
 346
 347 MODULE_LICENSE("GPL");
 348 MODULE_DESCRIPTION("XCBC keyed hash algorithm");