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