1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (C)2006 USAGI/WIDE Project 4 * 5 * Author: 6 * Kazunori Miyazawa <miyazawa@linux-ipv6.org> 7 */ 8 9 #include <crypto/internal/cipher.h> 10 #include <crypto/internal/hash.h> 11 #include <linux/err.h> 12 #include <linux/kernel.h> 13 #include <linux/module.h> 14 15 static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101, 16 0x02020202, 0x02020202, 0x02020202, 0x02020202, 17 0x03030303, 0x03030303, 0x03030303, 0x03030303}; 18 19 /* 20 * +------------------------ 21 * | <parent tfm> 22 * +------------------------ 23 * | xcbc_tfm_ctx 24 * +------------------------ 25 * | consts (block size * 2) 26 * +------------------------ 27 */ 28 struct xcbc_tfm_ctx { 29 struct crypto_cipher *child; 30 u8 ctx[]; 31 }; 32 33 /* 34 * +------------------------ 35 * | <shash desc> 36 * +------------------------ 37 * | xcbc_desc_ctx 38 * +------------------------ 39 * | odds (block size) 40 * +------------------------ 41 * | prev (block size) 42 * +------------------------ 43 */ 44 struct xcbc_desc_ctx { 45 unsigned int len; 46 u8 ctx[]; 47 }; 48 49 #define XCBC_BLOCKSIZE 16 50 51 static int crypto_xcbc_digest_setkey(struct crypto_shash *parent, 52 const u8 *inkey, unsigned int keylen) 53 { 54 unsigned long alignmask = crypto_shash_alignmask(parent); 55 struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent); 56 u8 *consts = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); 57 int err = 0; 58 u8 key1[XCBC_BLOCKSIZE]; 59 int bs = sizeof(key1); 60 61 if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen))) 62 return err; 63 64 crypto_cipher_encrypt_one(ctx->child, consts, (u8 *)ks + bs); 65 crypto_cipher_encrypt_one(ctx->child, consts + bs, (u8 *)ks + bs * 2); 66 crypto_cipher_encrypt_one(ctx->child, key1, (u8 *)ks); 67 68 return crypto_cipher_setkey(ctx->child, key1, bs); 69 70 } 71 72 static int crypto_xcbc_digest_init(struct shash_desc *pdesc) 73 { 74 unsigned long alignmask = crypto_shash_alignmask(pdesc->tfm); 75 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc); 76 int bs = crypto_shash_blocksize(pdesc->tfm); 77 u8 *prev = PTR_ALIGN(&ctx->ctx[0], alignmask + 1) + bs; 78 79 ctx->len = 0; 80 memset(prev, 0, bs); 81 82 return 0; 83 } 84 85 static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p, 86 unsigned int len) 87 { 88 struct crypto_shash *parent = pdesc->tfm; 89 unsigned long alignmask = crypto_shash_alignmask(parent); 90 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent); 91 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc); 92 struct crypto_cipher *tfm = tctx->child; 93 int bs = crypto_shash_blocksize(parent); 94 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); 95 u8 *prev = odds + bs; 96 97 /* checking the data can fill the block */ 98 if ((ctx->len + len) <= bs) { 99 memcpy(odds + ctx->len, p, len); 100 ctx->len += len; 101 return 0; 102 } 103 104 /* filling odds with new data and encrypting it */ 105 memcpy(odds + ctx->len, p, bs - ctx->len); 106 len -= bs - ctx->len; 107 p += bs - ctx->len; 108 109 crypto_xor(prev, odds, bs); 110 crypto_cipher_encrypt_one(tfm, prev, prev); 111 112 /* clearing the length */ 113 ctx->len = 0; 114 115 /* encrypting the rest of data */ 116 while (len > bs) { 117 crypto_xor(prev, p, bs); 118 crypto_cipher_encrypt_one(tfm, prev, prev); 119 p += bs; 120 len -= bs; 121 } 122 123 /* keeping the surplus of blocksize */ 124 if (len) { 125 memcpy(odds, p, len); 126 ctx->len = len; 127 } 128 129 return 0; 130 } 131 132 static int crypto_xcbc_digest_final(struct shash_desc *pdesc, u8 *out) 133 { 134 struct crypto_shash *parent = pdesc->tfm; 135 unsigned long alignmask = crypto_shash_alignmask(parent); 136 struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent); 137 struct xcbc_desc_ctx *ctx = shash_desc_ctx(pdesc); 138 struct crypto_cipher *tfm = tctx->child; 139 int bs = crypto_shash_blocksize(parent); 140 u8 *consts = PTR_ALIGN(&tctx->ctx[0], alignmask + 1); 141 u8 *odds = PTR_ALIGN(&ctx->ctx[0], alignmask + 1); 142 u8 *prev = odds + bs; 143 unsigned int offset = 0; 144 145 if (ctx->len != bs) { 146 unsigned int rlen; 147 u8 *p = odds + ctx->len; 148 149 *p = 0x80; 150 p++; 151 152 rlen = bs - ctx->len -1; 153 if (rlen) 154 memset(p, 0, rlen); 155 156 offset += bs; 157 } 158 159 crypto_xor(prev, odds, bs); 160 crypto_xor(prev, consts + offset, bs); 161 162 crypto_cipher_encrypt_one(tfm, out, prev); 163 164 return 0; 165 } 166 167 static int xcbc_init_tfm(struct crypto_tfm *tfm) 168 { 169 struct crypto_cipher *cipher; 170 struct crypto_instance *inst = (void *)tfm->__crt_alg; 171 struct crypto_cipher_spawn *spawn = crypto_instance_ctx(inst); 172 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm); 173 174 cipher = crypto_spawn_cipher(spawn); 175 if (IS_ERR(cipher)) 176 return PTR_ERR(cipher); 177 178 ctx->child = cipher; 179 180 return 0; 181 }; 182 183 static void xcbc_exit_tfm(struct crypto_tfm *tfm) 184 { 185 struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm); 186 crypto_free_cipher(ctx->child); 187 } 188 189 static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb) 190 { 191 struct shash_instance *inst; 192 struct crypto_cipher_spawn *spawn; 193 struct crypto_alg *alg; 194 unsigned long alignmask; 195 u32 mask; 196 int err; 197 198 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask); 199 if (err) 200 return err; 201 202 inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL); 203 if (!inst) 204 return -ENOMEM; 205 spawn = shash_instance_ctx(inst); 206 207 err = crypto_grab_cipher(spawn, shash_crypto_instance(inst), 208 crypto_attr_alg_name(tb[1]), 0, mask); 209 if (err) 210 goto err_free_inst; 211 alg = crypto_spawn_cipher_alg(spawn); 212 213 err = -EINVAL; 214 if (alg->cra_blocksize != XCBC_BLOCKSIZE) 215 goto err_free_inst; 216 217 err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg); 218 if (err) 219 goto err_free_inst; 220 221 alignmask = alg->cra_alignmask | 3; 222 inst->alg.base.cra_alignmask = alignmask; 223 inst->alg.base.cra_priority = alg->cra_priority; 224 inst->alg.base.cra_blocksize = alg->cra_blocksize; 225 226 inst->alg.digestsize = alg->cra_blocksize; 227 inst->alg.descsize = ALIGN(sizeof(struct xcbc_desc_ctx), 228 crypto_tfm_ctx_alignment()) + 229 (alignmask & 230 ~(crypto_tfm_ctx_alignment() - 1)) + 231 alg->cra_blocksize * 2; 232 233 inst->alg.base.cra_ctxsize = ALIGN(sizeof(struct xcbc_tfm_ctx), 234 alignmask + 1) + 235 alg->cra_blocksize * 2; 236 inst->alg.base.cra_init = xcbc_init_tfm; 237 inst->alg.base.cra_exit = xcbc_exit_tfm; 238 239 inst->alg.init = crypto_xcbc_digest_init; 240 inst->alg.update = crypto_xcbc_digest_update; 241 inst->alg.final = crypto_xcbc_digest_final; 242 inst->alg.setkey = crypto_xcbc_digest_setkey; 243 244 inst->free = shash_free_singlespawn_instance; 245 246 err = shash_register_instance(tmpl, inst); 247 if (err) { 248 err_free_inst: 249 shash_free_singlespawn_instance(inst); 250 } 251 return err; 252 } 253 254 static struct crypto_template crypto_xcbc_tmpl = { 255 .name = "xcbc", 256 .create = xcbc_create, 257 .module = THIS_MODULE, 258 }; 259 260 static int __init crypto_xcbc_module_init(void) 261 { 262 return crypto_register_template(&crypto_xcbc_tmpl); 263 } 264 265 static void __exit crypto_xcbc_module_exit(void) 266 { 267 crypto_unregister_template(&crypto_xcbc_tmpl); 268 } 269 270 subsys_initcall(crypto_xcbc_module_init); 271 module_exit(crypto_xcbc_module_exit); 272 273 MODULE_LICENSE("GPL"); 274 MODULE_DESCRIPTION("XCBC keyed hash algorithm"); 275 MODULE_ALIAS_CRYPTO("xcbc"); 276 MODULE_IMPORT_NS(CRYPTO_INTERNAL); 277