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 <crypto/scatterwalk.h>
  23 #include <linux/crypto.h>
  24 #include <linux/err.h>
  25 #include <linux/hardirq.h>
  26 #include <linux/kernel.h>
  27 #include <linux/mm.h>
  28 #include <linux/rtnetlink.h>
  29 #include <linux/slab.h>
  30 #include <linux/scatterlist.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_cipher *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         crypto_cipher_encrypt_one(ctx->child, key1, 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_cipher_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_update2(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_cipher *tfm = ctx->child;
 118         int bs = crypto_hash_blocksize(parent);
 119
 120         for (;;) {
 121                 struct page *pg = sg_page(sg);
 122                 unsigned int offset = sg->offset;
 123                 unsigned int slen = sg->length;
 124
 125                 if (unlikely(slen > nbytes))
 126                         slen = nbytes;
 127
 128                 nbytes -= slen;
 129
 130                 while (slen > 0) {
 131                         unsigned int len = min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
 132                         char *p = crypto_kmap(pg, 0) + offset;
 133
 134                         /* checking the data can fill the block */
 135                         if ((ctx->len + len) <= bs) {
 136                                 memcpy(ctx->odds + ctx->len, p, len);
 137                                 ctx->len += len;
 138                                 slen -= len;
 139
 140                                 /* checking the rest of the page */
 141                                 if (len + offset >= PAGE_SIZE) {
 142                                         offset = 0;
 143                                         pg++;
 144                                 } else
 145                                         offset += len;
 146
 147                                 crypto_kunmap(p, 0);
 148                                 crypto_yield(pdesc->flags);
 149                                 continue;
 150                         }
 151
 152                         /* filling odds with new data and encrypting it */
 153                         memcpy(ctx->odds + ctx->len, p, bs - ctx->len);
 154                         len -= bs - ctx->len;
 155                         p += bs - ctx->len;
 156
 157                         ctx->xor(ctx->prev, ctx->odds, bs);
 158                         crypto_cipher_encrypt_one(tfm, ctx->prev, ctx->prev);
 159
 160                         /* clearing the length */
 161                         ctx->len = 0;
 162
 163                         /* encrypting the rest of data */
 164                         while (len > bs) {
 165                                 ctx->xor(ctx->prev, p, bs);
 166                                 crypto_cipher_encrypt_one(tfm, ctx->prev,
 167                                                           ctx->prev);
 168                                 p += bs;
 169                                 len -= bs;
 170                         }
 171
 172                         /* keeping the surplus of blocksize */
 173                         if (len) {
 174                                 memcpy(ctx->odds, p, len);
 175                                 ctx->len = len;
 176                         }
 177                         crypto_kunmap(p, 0);
 178                         crypto_yield(pdesc->flags);
 179                         slen -= min(slen, ((unsigned int)(PAGE_SIZE)) - offset);
 180                         offset = 0;
 181                         pg++;
 182                 }
 183
 184                 if (!nbytes)
 185                         break;
 186                 sg = scatterwalk_sg_next(sg);
 187         }
 188
 189         return 0;
 190 }
 191
 192 static int crypto_xcbc_digest_update(struct hash_desc *pdesc,
 193                                      struct scatterlist *sg,
 194                                      unsigned int nbytes)
 195 {
 196         if (WARN_ON_ONCE(in_irq()))
 197                 return -EDEADLK;
 198         return crypto_xcbc_digest_update2(pdesc, sg, nbytes);
 199 }
 200
 201 static int crypto_xcbc_digest_final(struct hash_desc *pdesc, u8 *out)
 202 {
 203         struct crypto_hash *parent = pdesc->tfm;
 204         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(parent);
 205         struct crypto_cipher *tfm = ctx->child;
 206         int bs = crypto_hash_blocksize(parent);
 207         int err = 0;
 208
 209         if (ctx->len == bs) {
 210                 u8 key2[bs];
 211
 212                 if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
 213                         return err;
 214
 215                 crypto_cipher_encrypt_one(tfm, key2,
 216                                           (u8 *)(ctx->consts + bs));
 217
 218                 ctx->xor(ctx->prev, ctx->odds, bs);
 219                 ctx->xor(ctx->prev, key2, bs);
 220                 _crypto_xcbc_digest_setkey(parent, ctx);
 221
 222                 crypto_cipher_encrypt_one(tfm, out, ctx->prev);
 223         } else {
 224                 u8 key3[bs];
 225                 unsigned int rlen;
 226                 u8 *p = ctx->odds + ctx->len;
 227                 *p = 0x80;
 228                 p++;
 229
 230                 rlen = bs - ctx->len -1;
 231                 if (rlen)
 232                         memset(p, 0, rlen);
 233
 234                 if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
 235                         return err;
 236
 237                 crypto_cipher_encrypt_one(tfm, key3,
 238                                           (u8 *)(ctx->consts + bs * 2));
 239
 240                 ctx->xor(ctx->prev, ctx->odds, bs);
 241                 ctx->xor(ctx->prev, key3, bs);
 242
 243                 _crypto_xcbc_digest_setkey(parent, ctx);
 244
 245                 crypto_cipher_encrypt_one(tfm, out, ctx->prev);
 246         }
 247
 248         return 0;
 249 }
 250
 251 static int crypto_xcbc_digest(struct hash_desc *pdesc,
 252                   struct scatterlist *sg, unsigned int nbytes, u8 *out)
 253 {
 254         if (WARN_ON_ONCE(in_irq()))
 255                 return -EDEADLK;
 256
 257         crypto_xcbc_digest_init(pdesc);
 258         crypto_xcbc_digest_update2(pdesc, sg, nbytes);
 259         return crypto_xcbc_digest_final(pdesc, out);
 260 }
 261
 262 static int xcbc_init_tfm(struct crypto_tfm *tfm)
 263 {
 264         struct crypto_cipher *cipher;
 265         struct crypto_instance *inst = (void *)tfm->__crt_alg;
 266         struct crypto_spawn *spawn = crypto_instance_ctx(inst);
 267         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
 268         int bs = crypto_hash_blocksize(__crypto_hash_cast(tfm));
 269
 270         cipher = crypto_spawn_cipher(spawn);
 271         if (IS_ERR(cipher))
 272                 return PTR_ERR(cipher);
 273
 274         switch(bs) {
 275         case 16:
 276                 ctx->xor = xor_128;
 277                 break;
 278         default:
 279                 return -EINVAL;
 280         }
 281
 282         ctx->child = cipher;
 283         ctx->odds = (u8*)(ctx+1);
 284         ctx->prev = ctx->odds + bs;
 285         ctx->key = ctx->prev + bs;
 286
 287         return 0;
 288 };
 289
 290 static void xcbc_exit_tfm(struct crypto_tfm *tfm)
 291 {
 292         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
 293         crypto_free_cipher(ctx->child);
 294 }
 295
 296 static struct crypto_instance *xcbc_alloc(struct rtattr **tb)
 297 {
 298         struct crypto_instance *inst;
 299         struct crypto_alg *alg;
 300         int err;
 301
 302         err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_HASH);
 303         if (err)
 304                 return ERR_PTR(err);
 305
 306         alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
 307                                   CRYPTO_ALG_TYPE_MASK);
 308         if (IS_ERR(alg))
 309                 return ERR_CAST(alg);
 310
 311         switch(alg->cra_blocksize) {
 312         case 16:
 313                 break;
 314         default:
 315                 inst = ERR_PTR(-EINVAL);
 316                 goto out_put_alg;
 317         }
 318
 319         inst = crypto_alloc_instance("xcbc", alg);
 320         if (IS_ERR(inst))
 321                 goto out_put_alg;
 322
 323         inst->alg.cra_flags = CRYPTO_ALG_TYPE_HASH;
 324         inst->alg.cra_priority = alg->cra_priority;
 325         inst->alg.cra_blocksize = alg->cra_blocksize;
 326         inst->alg.cra_alignmask = alg->cra_alignmask;
 327         inst->alg.cra_type = &crypto_hash_type;
 328
 329         inst->alg.cra_hash.digestsize = alg->cra_blocksize;
 330         inst->alg.cra_ctxsize = sizeof(struct crypto_xcbc_ctx) +
 331                                 ALIGN(inst->alg.cra_blocksize * 3, sizeof(void *));
 332         inst->alg.cra_init = xcbc_init_tfm;
 333         inst->alg.cra_exit = xcbc_exit_tfm;
 334
 335         inst->alg.cra_hash.init = crypto_xcbc_digest_init;
 336         inst->alg.cra_hash.update = crypto_xcbc_digest_update;
 337         inst->alg.cra_hash.final = crypto_xcbc_digest_final;
 338         inst->alg.cra_hash.digest = crypto_xcbc_digest;
 339         inst->alg.cra_hash.setkey = crypto_xcbc_digest_setkey;
 340
 341 out_put_alg:
 342         crypto_mod_put(alg);
 343         return inst;
 344 }
 345
 346 static void xcbc_free(struct crypto_instance *inst)
 347 {
 348         crypto_drop_spawn(crypto_instance_ctx(inst));
 349         kfree(inst);
 350 }
 351
 352 static struct crypto_template crypto_xcbc_tmpl = {
 353         .name = "xcbc",
 354         .alloc = xcbc_alloc,
 355         .free = xcbc_free,
 356         .module = THIS_MODULE,
 357 };
 358
 359 static int __init crypto_xcbc_module_init(void)
 360 {
 361         return crypto_register_template(&crypto_xcbc_tmpl);
 362 }
 363
 364 static void __exit crypto_xcbc_module_exit(void)
 365 {
 366         crypto_unregister_template(&crypto_xcbc_tmpl);
 367 }
 368
 369 module_init(crypto_xcbc_module_init);
 370 module_exit(crypto_xcbc_module_exit);
 371
 372 MODULE_LICENSE("GPL");
 373 MODULE_DESCRIPTION("XCBC keyed hash algorithm");