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