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, see <http://www.gnu.org/licenses/>. 16 * 17 * Author: 18 * Kazunori Miyazawa <miyazawa@linux-ipv6.org> 19 */ 20 21 #include <crypto/internal/hash.h> 22 #include <linux/err.h> 23 #include <linux/kernel.h> 24 #include <linux/module.h> 25 26 static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101, 27 0x02020202, 0x02020202, 0x02020202, 0x02020202, 28 0x03030303, 0x03030303, 0x03030303, 0x03030303}; 29 30 /* 31 * +------------------------ 32 * | <parent tfm> 33 * +------------------------ 34 * | xcbc_tfm_ctx 35 * +------------------------ 36 * | consts (block size * 2) 37 * +------------------------ 38 */ 39 struct xcbc_tfm_ctx { 40 struct crypto_cipher *child; 41 u8 ctx[]; 42 }; 43 44 /* 45 * +------------------------ 46 * | <shash desc> 47 * +------------------------ 48 * | xcbc_desc_ctx 49 * +------------------------ 50 * | odds (block size) 51 * +------------------------ 52 * | prev (block size) 53 * +------------------------ 54 */ 55 struct xcbc_desc_ctx { 56 unsigned int len; 57 u8 ctx[]; 58 }; 59 60 #define XCBC_BLOCKSIZE 16 61 62 static int crypto_xcbc_digest_setkey(struct crypto_shash *parent, 63 const u8 *inkey, unsigned int keylen) 64 { 65 unsigned long alignmask = crypto_shash_alignmask(parent); 66 struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent); 67 u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); 68 int err = 0; 69 u8 key1[XCBC_BLOCKSIZE]; 70 int bs = sizeof(key1); 71 72 if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen))) 73 return err; 74 75 crypto_cipher_encrypt_one(ctx->child, consts, (u8 *)ks + bs); 76 crypto_cipher_encrypt_one(ctx->child, consts + bs, (u8 *)ks + bs * 2); 77 crypto_cipher_encrypt_one(ctx->child, key1, (u8 *)ks); 78 79 return crypto_cipher_setkey(ctx->child, key1, bs); 80 81 } 82 83 static int crypto_xcbc_digest_init(struct shash_desc *pdesc) 84 { 85 unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm); 86 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc); 87 int bs = crypto_shash_blocksize(pdesc->tfm); 88 u8 *prev = PTR_ALIGN(&ctx->ctx[0], alignmask + 1) + bs; 89 90 ctx->len = 0; 91 memset(prev, 0, bs); 92 93 return 0; 94 } 95 96 static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p, 97 unsigned int len) 98 { 99 struct crypto_shash *parent = pdesc->tfm; 100 unsigned long alignmask = crypto_shash_alignmask(parent); 101 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent); 102 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc); 103 struct crypto_cipher *tfm = tctx->child; 104 int bs = crypto_shash_blocksize(parent); 105 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); 106 u8 *prev = odds + bs; 107 108 /* checking the data can fill the block */ 109 if ((ctx->len + len) <= bs) { 110 memcpy(odds + ctx->len, p, len); 111 ctx->len += len; 112 return 0; 113 } 114 115 /* filling odds with new data and encrypting it */ 116 memcpy(odds + ctx->len, p, bs - ctx->len); 117 len -= bs - ctx->len; 118 p += bs - ctx->len; 119 120 crypto_xor(prev, odds, bs); 121 crypto_cipher_encrypt_one(tfm, prev, prev); 122 123 /* clearing the length */ 124 ctx->len = 0; 125 126 /* encrypting the rest of data */ 127 while (len > bs) { 128 crypto_xor(prev, p, bs); 129 crypto_cipher_encrypt_one(tfm, prev, prev); 130 p += bs; 131 len -= bs; 132 } 133 134 /* keeping the surplus of blocksize */ 135 if (len) { 136 memcpy(odds, p, len); 137 ctx->len = len; 138 } 139 140 return 0; 141 } 142 143 static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out) 144 { 145 struct crypto_shash *parent = pdesc->tfm; 146 unsigned long alignmask = crypto_shash_alignmask(parent); 147 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent); 148 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc); 149 struct crypto_cipher *tfm = tctx->child; 150 int bs = crypto_shash_blocksize(parent); 151 u8 *consts = PTR_ALIGN(&tctx->ctx[0], alignmask + 1); 152 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); 153 u8 *prev = odds + bs; 154 unsigned int offset = 0; 155 156 if (ctx->len != bs) { 157 unsigned int rlen; 158 u8 *p = odds + ctx->len; 159 160 *p = 0x80; 161 p++; 162 163 rlen = bs - ctx->len -1; 164 if (rlen) 165 memset(p, 0, rlen); 166 167 offset += bs; 168 } 169 170 crypto_xor(prev, odds, bs); 171 crypto_xor(prev, consts + offset, bs); 172 173 crypto_cipher_encrypt_one(tfm, out, prev); 174 175 return 0; 176 } 177 178 static int xcbc_init_tfm(struct crypto_tfm *tfm) 179 { 180 struct crypto_cipher *cipher; 181 struct crypto_instance *inst = (void *)tfm->__crt_alg; 182 struct crypto_spawn *spawn = crypto_instance_ctx(inst); 183 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm); 184 185 cipher = crypto_spawn_cipher(spawn); 186 if (IS_ERR(cipher)) 187 return PTR_ERR(cipher); 188 189 ctx->child = cipher; 190 191 return 0; 192 }; 193 194 static void xcbc_exit_tfm(struct crypto_tfm *tfm) 195 { 196 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm); 197 crypto_free_cipher(ctx->child); 198 } 199 200 static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb) 201 { 202 struct shash_instance *inst; 203 struct crypto_alg *alg; 204 unsigned long alignmask; 205 int err; 206 207 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH); 208 if (err) 209 return err; 210 211 alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER, 212 CRYPTO_ALG_TYPE_MASK); 213 if (IS_ERR(alg)) 214 return PTR_ERR(alg); 215 216 switch(alg->cra_blocksize) { 217 case XCBC_BLOCKSIZE: 218 break; 219 default: 220 goto out_put_alg; 221 } 222 223 inst = shash_alloc_instance("xcbc", alg); 224 err = PTR_ERR(inst); 225 if (IS_ERR(inst)) 226 goto out_put_alg; 227 228 err = crypto_init_spawn(shash_instance_ctx(inst), alg, 229 shash_crypto_instance(inst), 230 CRYPTO_ALG_TYPE_MASK); 231 if (err) 232 goto out_free_inst; 233 234 alignmask = alg->cra_alignmask | 3; 235 inst->alg.base.cra_alignmask = alignmask; 236 inst->alg.base.cra_priority = alg->cra_priority; 237 inst->alg.base.cra_blocksize = alg->cra_blocksize; 238 239 inst->alg.digestsize = alg->cra_blocksize; 240 inst->alg.descsize = ALIGN(sizeof(struct xcbc_desc_ctx), 241 crypto_tfm_ctx_alignment()) + 242 (alignmask & 243 ~(crypto_tfm_ctx_alignment() - 1)) + 244 alg->cra_blocksize * 2; 245 246 inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct xcbc_tfm_ctx), 247 alignmask + 1) + 248 alg->cra_blocksize * 2; 249 inst->alg.base.cra_init = xcbc_init_tfm; 250 inst->alg.base.cra_exit = xcbc_exit_tfm; 251 252 inst->alg.init = crypto_xcbc_digest_init; 253 inst->alg.update = crypto_xcbc_digest_update; 254 inst->alg.final = crypto_xcbc_digest_final; 255 inst->alg.setkey = crypto_xcbc_digest_setkey; 256 257 err = shash_register_instance(tmpl, inst); 258 if (err) { 259 out_free_inst: 260 shash_free_instance(shash_crypto_instance(inst)); 261 } 262 263 out_put_alg: 264 crypto_mod_put(alg); 265 return err; 266 } 267 268 static struct crypto_template crypto_xcbc_tmpl = { 269 .name = "xcbc", 270 .create = xcbc_create, 271 .free = shash_free_instance, 272 .module = THIS_MODULE, 273 }; 274 275 static int __init crypto_xcbc_module_init(void) 276 { 277 return crypto_register_template(&crypto_xcbc_tmpl); 278 } 279 280 static void __exit crypto_xcbc_module_exit(void) 281 { 282 crypto_unregister_template(&crypto_xcbc_tmpl); 283 } 284 285 subsys_initcall(crypto_xcbc_module_init); 286 module_exit(crypto_xcbc_module_exit); 287 288 MODULE_LICENSE("GPL"); 289 MODULE_DESCRIPTION("XCBC keyed hash algorithm"); 290 MODULE_ALIAS_CRYPTO("xcbc"); 291