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         unsigned int i = 0;
 120
 121         do {
 122
 123                 struct page *pg = sg_page(&sg[i]);
 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(pdesc->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                         crypto_cipher_encrypt_one(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                                 crypto_cipher_encrypt_one(tfm, ctx->prev,
 164                                                           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(pdesc->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_cipher *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                 crypto_cipher_encrypt_one(tfm, key2,
 211                                           (u8 *)(ctx->consts + bs));
 212
 213                 ctx->xor(ctx->prev, ctx->odds, bs);
 214                 ctx->xor(ctx->prev, key2, bs);
 215                 _crypto_xcbc_digest_setkey(parent, ctx);
 216
 217                 crypto_cipher_encrypt_one(tfm, out, ctx->prev);
 218         } else {
 219                 u8 key3[bs];
 220                 unsigned int rlen;
 221                 u8 *p = ctx->odds + ctx->len;
 222                 *p = 0x80;
 223                 p++;
 224
 225                 rlen = bs - ctx->len -1;
 226                 if (rlen)
 227                         memset(p, 0, rlen);
 228
 229                 if ((err = crypto_cipher_setkey(tfm, ctx->key, ctx->keylen)) != 0)
 230                         return err;
 231
 232                 crypto_cipher_encrypt_one(tfm, key3,
 233                                           (u8 *)(ctx->consts + bs * 2));
 234
 235                 ctx->xor(ctx->prev, ctx->odds, bs);
 236                 ctx->xor(ctx->prev, key3, bs);
 237
 238                 _crypto_xcbc_digest_setkey(parent, ctx);
 239
 240                 crypto_cipher_encrypt_one(tfm, out, ctx->prev);
 241         }
 242
 243         return 0;
 244 }
 245
 246 static int crypto_xcbc_digest(struct hash_desc *pdesc,
 247                   struct scatterlist *sg, unsigned int nbytes, u8 *out)
 248 {
 249         if (WARN_ON_ONCE(in_irq()))
 250                 return -EDEADLK;
 251
 252         crypto_xcbc_digest_init(pdesc);
 253         crypto_xcbc_digest_update2(pdesc, sg, nbytes);
 254         return crypto_xcbc_digest_final(pdesc, out);
 255 }
 256
 257 static int xcbc_init_tfm(struct crypto_tfm *tfm)
 258 {
 259         struct crypto_cipher *cipher;
 260         struct crypto_instance *inst = (void *)tfm->__crt_alg;
 261         struct crypto_spawn *spawn = crypto_instance_ctx(inst);
 262         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
 263         int bs = crypto_hash_blocksize(__crypto_hash_cast(tfm));
 264
 265         cipher = crypto_spawn_cipher(spawn);
 266         if (IS_ERR(cipher))
 267                 return PTR_ERR(cipher);
 268
 269         switch(bs) {
 270         case 16:
 271                 ctx->xor = xor_128;
 272                 break;
 273         default:
 274                 return -EINVAL;
 275         }
 276
 277         ctx->child = cipher;
 278         ctx->odds = (u8*)(ctx+1);
 279         ctx->prev = ctx->odds + bs;
 280         ctx->key = ctx->prev + bs;
 281
 282         return 0;
 283 };
 284
 285 static void xcbc_exit_tfm(struct crypto_tfm *tfm)
 286 {
 287         struct crypto_xcbc_ctx *ctx = crypto_hash_ctx_aligned(__crypto_hash_cast(tfm));
 288         crypto_free_cipher(ctx->child);
 289 }
 290
 291 static struct crypto_instance *xcbc_alloc(struct rtattr **tb)
 292 {
 293         struct crypto_instance *inst;
 294         struct crypto_alg *alg;
 295         int err;
 296
 297         err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_HASH);
 298         if (err)
 299                 return ERR_PTR(err);
 300
 301         alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
 302                                   CRYPTO_ALG_TYPE_MASK);
 303         if (IS_ERR(alg))
 304                 return ERR_CAST(alg);
 305
 306         switch(alg->cra_blocksize) {
 307         case 16:
 308                 break;
 309         default:
 310                 inst = ERR_PTR(-EINVAL);
 311                 goto out_put_alg;
 312         }
 313
 314         inst = crypto_alloc_instance("xcbc", alg);
 315         if (IS_ERR(inst))
 316                 goto out_put_alg;
 317
 318         inst->alg.cra_flags = CRYPTO_ALG_TYPE_HASH;
 319         inst->alg.cra_priority = alg->cra_priority;
 320         inst->alg.cra_blocksize = alg->cra_blocksize;
 321         inst->alg.cra_alignmask = alg->cra_alignmask;
 322         inst->alg.cra_type = &crypto_hash_type;
 323
 324         inst->alg.cra_hash.digestsize = alg->cra_blocksize;
 325         inst->alg.cra_ctxsize = sizeof(struct crypto_xcbc_ctx) +
 326                                 ALIGN(inst->alg.cra_blocksize * 3, sizeof(void *));
 327         inst->alg.cra_init = xcbc_init_tfm;
 328         inst->alg.cra_exit = xcbc_exit_tfm;
 329
 330         inst->alg.cra_hash.init = crypto_xcbc_digest_init;
 331         inst->alg.cra_hash.update = crypto_xcbc_digest_update;
 332         inst->alg.cra_hash.final = crypto_xcbc_digest_final;
 333         inst->alg.cra_hash.digest = crypto_xcbc_digest;
 334         inst->alg.cra_hash.setkey = crypto_xcbc_digest_setkey;
 335
 336 out_put_alg:
 337         crypto_mod_put(alg);
 338         return inst;
 339 }
 340
 341 static void xcbc_free(struct crypto_instance *inst)
 342 {
 343         crypto_drop_spawn(crypto_instance_ctx(inst));
 344         kfree(inst);
 345 }
 346
 347 static struct crypto_template crypto_xcbc_tmpl = {
 348         .name = "xcbc",
 349         .alloc = xcbc_alloc,
 350         .free = xcbc_free,
 351         .module = THIS_MODULE,
 352 };
 353
 354 static int __init crypto_xcbc_module_init(void)
 355 {
 356         return crypto_register_template(&crypto_xcbc_tmpl);
 357 }
 358
 359 static void __exit crypto_xcbc_module_exit(void)
 360 {
 361         crypto_unregister_template(&crypto_xcbc_tmpl);
 362 }
 363
 364 module_init(crypto_xcbc_module_init);
 365 module_exit(crypto_xcbc_module_exit);
 366
 367 MODULE_LICENSE("GPL");
 368 MODULE_DESCRIPTION("XCBC keyed hash algorithm");