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/hardirq.h>
  25 #include <linux/kernel.h>
  26 #include <linux/mm.h>
  27 #include <linux/rtnetlink.h>
  28 #include <linux/slab.h>
  29 #include <linux/scatterlist.h>
  30 #include "internal.h"
  31
  32 static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
  33                            0x02020202, 0x02020202, 0x02020202, 0x02020202,
  34                            0x03030303, 0x03030303, 0x03030303, 0x03030303};
  35 /*
  36  * +------------------------
  37  * | <parent tfm>
  38  * +------------------------
  39  * | crypto_xcbc_ctx
  40  * +------------------------
  41  * | odds (block size)
  42  * +------------------------
  43  * | prev (block size)
  44  * +------------------------
  45  * | key (block size)
  46  * +------------------------
  47  * | consts (block size * 3)
  48  * +------------------------
  49  */
  50 struct crypto_xcbc_ctx {
  51         struct crypto_tfm *child;
  52         u8 *odds;
  53         u8 *prev;
  54         u8 *key;
  55         u8 *consts;
  56         void (*xor)(u8 *a, const u8 *b, unsigned int bs);
  57         unsigned int keylen;
  58         unsigned int len;
  59 };
  60
  61 static void xor_128(u8 *a, const u8 *b, unsigned int bs)
  62 {
  63         ((u32 *)a)[0] ^= ((u32 *)b)[0];
  64         ((u32 *)a)[1] ^= ((u32 *)b)[1];
  65         ((u32 *)a)[2] ^= ((u32 *)b)[2];
  66         ((u32 *)a)[3] ^= ((u32 *)b)[3];
  67 }
  68
  69 static int _crypto_xcbc_digest_setkey(struct crypto_hash *parent,
  70                                       struct crypto_xcbc_ctx *ctx)
  71 {
  72         int bs = crypto_hash_blocksize(parent);
  73         int err = 0;
  74         u8 key1[bs];
  75
  76         if ((err = crypto_cipher_setkey(ctx->child, ctx->key, ctx->keylen)))
  77             return err;
  78
  79         ctx->child->__crt_alg->cra_cipher.cia_encrypt(ctx->child, key1,
  80                         ctx->consts);
  81
  82         return crypto_cipher_setkey(ctx->child, key1, bs);
  83 }
  84
  85 static int crypto_xcbc_digest_setkey(struct crypto_hash *parent,
  86                                      const u8 *inkey, unsigned int keylen)
  87 {
  88         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
  89
  90         if (keylen != crypto_tfm_alg_blocksize(ctx->child))
  91                 return -EINVAL;
  92
  93         ctx->keylen = keylen;
  94         memcpy(ctx->key, inkey, keylen);
  95         ctx->consts = (u8*)ks;
  96
  97         return _crypto_xcbc_digest_setkey(parent, ctx);
  98 }
  99
 100 static int crypto_xcbc_digest_init(struct hash_desc *pdesc)
 101 {
 102         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(pdesc->tfm);
 103         int bs = crypto_hash_blocksize(pdesc->tfm);
 104
 105         ctx->len = 0;
 106         memset(ctx->odds, 0, bs);
 107         memset(ctx->prev, 0, bs);
 108
 109         return 0;
 110 }
 111
 112 static int crypto_xcbc_digest_update2(struct hash_desc *pdesc,
 113                                       struct scatterlist *sg,
 114                                       unsigned int nbytes)
 115 {
 116         struct crypto_hash *parent = pdesc->tfm;
 117         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
 118         struct crypto_tfm *tfm = ctx->child;
 119         int bs = crypto_hash_blocksize(parent);
 120         unsigned int i = 0;
 121
 122         do {
 123
 124                 struct page *pg = sg[i].page;
 125                 unsigned int offset = sg[i].offset;
 126                 unsigned int slen = sg[i].length;
 127
 128                 while (slen > 0) {
 129                         unsigned int len = min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
 130                         char *p = crypto_kmap(pg, 0) + offset;
 131
 132                         /* checking the data can fill the block */
 133                         if ((ctx->len + len) <= bs) {
 134                                 memcpy(ctx->odds + ctx->len, p, len);
 135                                 ctx->len += len;
 136                                 slen -= len;
 137
 138                                 /* checking the rest of the page */
 139                                 if (len + offset >= PAGE_SIZE) {
 140                                         offset = 0;
 141                                         pg++;
 142                                 } else
 143                                         offset += len;
 144
 145                                 crypto_kunmap(p, 0);
 146                                 crypto_yield(tfm->crt_flags);
 147                                 continue;
 148                         }
 149
 150                         /* filling odds with new data and encrypting it */
 151                         memcpy(ctx->odds + ctx->len, p, bs - ctx->len);
 152                         len -= bs - ctx->len;
 153                         p += bs - ctx->len;
 154
 155                         ctx->xor(ctx->prev, ctx->odds, bs);
 156                         tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, ctx->prev, ctx->prev);
 157
 158                         /* clearing the length */
 159                         ctx->len = 0;
 160
 161                         /* encrypting the rest of data */
 162                         while (len > bs) {
 163                                 ctx->xor(ctx->prev, p, bs);
 164                                 tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, ctx->prev, ctx->prev);
 165                                 p += bs;
 166                                 len -= bs;
 167                         }
 168
 169                         /* keeping the surplus of blocksize */
 170                         if (len) {
 171                                 memcpy(ctx->odds, p, len);
 172                                 ctx->len = len;
 173                         }
 174                         crypto_kunmap(p, 0);
 175                         crypto_yield(tfm->crt_flags);
 176                         slen -= min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
 177                         offset = 0;
 178                         pg++;
 179                 }
 180                 nbytes-=sg[i].length;
 181                 i++;
 182         } while (nbytes>0);
 183
 184         return 0;
 185 }
 186
 187 static int crypto_xcbc_digest_update(struct hash_desc *pdesc,
 188                                      struct scatterlist *sg,
 189                                      unsigned int nbytes)
 190 {
 191         if (WARN_ON_ONCE(in_irq()))
 192                 return -EDEADLK;
 193         return crypto_xcbc_digest_update2(pdesc, sg, nbytes);
 194 }
 195
 196 static int crypto_xcbc_digest_final(struct hash_desc *pdesc, u8 *out)
 197 {
 198         struct crypto_hash *parent = pdesc->tfm;
 199         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
 200         struct crypto_tfm *tfm = ctx->child;
 201         int bs = crypto_hash_blocksize(parent);
 202         int err = 0;
 203
 204         if (ctx->len == bs) {
 205                 u8 key2[bs];
 206
 207                 if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
 208                         return err;
 209
 210                 tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, key2, (const u8*)(ctx->consts+bs));
 211
 212                 ctx->xor(ctx->prev, ctx->odds, bs);
 213                 ctx->xor(ctx->prev, key2, bs);
 214                 _crypto_xcbc_digest_setkey(parent, ctx);
 215
 216                 tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, out, ctx->prev);
 217         } else {
 218                 u8 key3[bs];
 219                 unsigned int rlen;
 220                 u8 *p = ctx->odds + ctx->len;
 221                 *p = 0x80;
 222                 p++;
 223
 224                 rlen = bs - ctx->len -1;
 225                 if (rlen)
 226                         memset(p, 0, rlen);
 227
 228                 if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
 229                         return err;
 230
 231                 tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, key3, (const u8*)(ctx->consts+bs*2));
 232
 233                 ctx->xor(ctx->prev, ctx->odds, bs);
 234                 ctx->xor(ctx->prev, key3, bs);
 235
 236                 _crypto_xcbc_digest_setkey(parent, ctx);
 237
 238                 tfm->__crt_alg->cra_cipher.cia_encrypt(tfm, out, ctx->prev);
 239         }
 240
 241         return 0;
 242 }
 243
 244 static int crypto_xcbc_digest(struct hash_desc *pdesc,
 245                   struct scatterlist *sg, unsigned int nbytes, u8 *out)
 246 {
 247         if (WARN_ON_ONCE(in_irq()))
 248                 return -EDEADLK;
 249
 250         crypto_xcbc_digest_init(pdesc);
 251         crypto_xcbc_digest_update2(pdesc, sg, nbytes);
 252         return crypto_xcbc_digest_final(pdesc, out);
 253 }
 254
 255 static int xcbc_init_tfm(struct crypto_tfm *tfm)
 256 {
 257         struct crypto_instance *inst = (void *)tfm->__crt_alg;
 258         struct crypto_spawn *spawn = crypto_instance_ctx(inst);
 259         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
 260         int bs = crypto_hash_blocksize(__crypto_hash_cast(tfm));
 261
 262         tfm = crypto_spawn_tfm(spawn);
 263         if (IS_ERR(tfm))
 264                 return PTR_ERR(tfm);
 265
 266         switch(bs) {
 267         case 16:
 268                 ctx->xor = xor_128;
 269                 break;
 270         default:
 271                 return -EINVAL;
 272         }
 273
 274         ctx->child = crypto_cipher_cast(tfm);
 275         ctx->odds = (u8*)(ctx+1);
 276         ctx->prev = ctx->odds + bs;
 277         ctx->key = ctx->prev + bs;
 278
 279         return 0;
 280 };
 281
 282 static void xcbc_exit_tfm(struct crypto_tfm *tfm)
 283 {
 284         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
 285         crypto_free_cipher(ctx->child);
 286 }
 287
 288 static struct crypto_instance *xcbc_alloc(void *param, unsigned int len)
 289 {
 290         struct crypto_instance *inst;
 291         struct crypto_alg *alg;
 292         alg = crypto_get_attr_alg(param, len, CRYPTO_ALG_TYPE_CIPHER,
 293                                   CRYPTO_ALG_TYPE_HASH_MASK | CRYPTO_ALG_ASYNC);
 294         if (IS_ERR(alg))
 295                 return ERR_PTR(PTR_ERR(alg));
 296
 297         switch(alg->cra_blocksize) {
 298         case 16:
 299                 break;
 300         default:
 301                 return ERR_PTR(PTR_ERR(alg));
 302         }
 303
 304         inst = crypto_alloc_instance("xcbc", alg);
 305         if (IS_ERR(inst))
 306                 goto out_put_alg;
 307
 308         inst->alg.cra_flags = CRYPTO_ALG_TYPE_HASH;
 309         inst->alg.cra_priority = alg->cra_priority;
 310         inst->alg.cra_blocksize = alg->cra_blocksize;
 311         inst->alg.cra_alignmask = alg->cra_alignmask;
 312         inst->alg.cra_type = &crypto_hash_type;
 313
 314         inst->alg.cra_hash.digestsize =
 315                 (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) ==
 316                 CRYPTO_ALG_TYPE_HASH ? alg->cra_hash.digestsize :
 317                                        alg->cra_blocksize;
 318         inst->alg.cra_ctxsize = sizeof(struct crypto_xcbc_ctx) +
 319                                 ALIGN(inst->alg.cra_blocksize * 3, sizeof(void *));
 320         inst->alg.cra_init = xcbc_init_tfm;
 321         inst->alg.cra_exit = xcbc_exit_tfm;
 322
 323         inst->alg.cra_hash.init = crypto_xcbc_digest_init;
 324         inst->alg.cra_hash.update = crypto_xcbc_digest_update;
 325         inst->alg.cra_hash.final = crypto_xcbc_digest_final;
 326         inst->alg.cra_hash.digest = crypto_xcbc_digest;
 327         inst->alg.cra_hash.setkey = crypto_xcbc_digest_setkey;
 328
 329 out_put_alg:
 330         crypto_mod_put(alg);
 331         return inst;
 332 }
 333
 334 static void xcbc_free(struct crypto_instance *inst)
 335 {
 336         crypto_drop_spawn(crypto_instance_ctx(inst));
 337         kfree(inst);
 338 }
 339
 340 static struct crypto_template crypto_xcbc_tmpl = {
 341         .name = "xcbc",
 342         .alloc = xcbc_alloc,
 343         .free = xcbc_free,
 344         .module = THIS_MODULE,
 345 };
 346
 347 static int __init crypto_xcbc_module_init(void)
 348 {
 349         return crypto_register_template(&crypto_xcbc_tmpl);
 350 }
 351
 352 static void __exit crypto_xcbc_module_exit(void)
 353 {
 354         crypto_unregister_template(&crypto_xcbc_tmpl);
 355 }
 356
 357 module_init(crypto_xcbc_module_init);
 358 module_exit(crypto_xcbc_module_exit);
 359
 360 MODULE_LICENSE("GPL");
 361 MODULE_DESCRIPTION("XCBC keyed hash algorithm");