xcbc.c

  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 <crypto/utils.h>
 12#include <linux/err.h>
 13#include <linux/kernel.h>
 14#include <linux/module.h>
 15#include <linux/slab.h>
 16#include <linux/string.h>
 17
 18static u_int32_t ks[12] = {0x01010101, 0x01010101, 0x01010101, 0x01010101,
 19			   0x02020202, 0x02020202, 0x02020202, 0x02020202,
 20			   0x03030303, 0x03030303, 0x03030303, 0x03030303};
 21
 22/*
 23 * +------------------------
 24 * | <parent tfm>
 25 * +------------------------
 26 * | xcbc_tfm_ctx
 27 * +------------------------
 28 * | consts (block size * 2)
 29 * +------------------------
 30 */
 31struct xcbc_tfm_ctx {
 32	struct crypto_cipher *child;
 33	u8 consts[];
 34};
 35
 36#define XCBC_BLOCKSIZE	16
 37
 38static int crypto_xcbc_digest_setkey(struct crypto_shash *parent,
 39				     const u8 *inkey, unsigned int keylen)
 40{
 41	struct xcbc_tfm_ctx *ctx = crypto_shash_ctx(parent);
 42	u8 *consts = ctx->consts;
 43	int err = 0;
 44	u8 key1[XCBC_BLOCKSIZE];
 45	int bs = sizeof(key1);
 46
 47	if ((err = crypto_cipher_setkey(ctx->child, inkey, keylen)))
 48		return err;
 49
 50	crypto_cipher_encrypt_one(ctx->child, consts, (u8 *)ks + bs);
 51	crypto_cipher_encrypt_one(ctx->child, consts + bs, (u8 *)ks + bs * 2);
 52	crypto_cipher_encrypt_one(ctx->child, key1, (u8 *)ks);
 53
 54	return crypto_cipher_setkey(ctx->child, key1, bs);
 55
 56}
 57
 58static int crypto_xcbc_digest_init(struct shash_desc *pdesc)
 59{
 60	int bs = crypto_shash_blocksize(pdesc->tfm);
 61	u8 *prev = shash_desc_ctx(pdesc);
 62
 63	memset(prev, 0, bs);
 64	return 0;
 65}
 66
 67static int crypto_xcbc_digest_update(struct shash_desc *pdesc, const u8 *p,
 68				     unsigned int len)
 69{
 70	struct crypto_shash *parent = pdesc->tfm;
 71	struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
 72	struct crypto_cipher *tfm = tctx->child;
 73	int bs = crypto_shash_blocksize(parent);
 74	u8 *prev = shash_desc_ctx(pdesc);
 75
 76	do {
 77		crypto_xor(prev, p, bs);
 78		crypto_cipher_encrypt_one(tfm, prev, prev);
 79		p += bs;
 80		len -= bs;
 81	} while (len >= bs);
 82	return len;
 83}
 84
 85static int crypto_xcbc_digest_finup(struct shash_desc *pdesc, const u8 *src,
 86				    unsigned int len, u8 *out)
 87{
 88	struct crypto_shash *parent = pdesc->tfm;
 89	struct xcbc_tfm_ctx *tctx = crypto_shash_ctx(parent);
 90	struct crypto_cipher *tfm = tctx->child;
 91	int bs = crypto_shash_blocksize(parent);
 92	u8 *prev = shash_desc_ctx(pdesc);
 93	unsigned int offset = 0;
 94
 95	crypto_xor(prev, src, len);
 96	if (len != bs) {
 97		prev[len] ^= 0x80;
 98		offset += bs;
 99	}
100	crypto_xor(prev, &tctx->consts[offset], bs);
101	crypto_cipher_encrypt_one(tfm, out, prev);
102	return 0;
103}
104
105static int xcbc_init_tfm(struct crypto_tfm *tfm)
106{
107	struct crypto_cipher *cipher;
108	struct crypto_instance *inst = (void *)tfm->__crt_alg;
109	struct crypto_cipher_spawn *spawn = crypto_instance_ctx(inst);
110	struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
111
112	cipher = crypto_spawn_cipher(spawn);
113	if (IS_ERR(cipher))
114		return PTR_ERR(cipher);
115
116	ctx->child = cipher;
117
118	return 0;
119};
120
121static void xcbc_exit_tfm(struct crypto_tfm *tfm)
122{
123	struct xcbc_tfm_ctx *ctx = crypto_tfm_ctx(tfm);
124	crypto_free_cipher(ctx->child);
125}
126
127static int xcbc_create(struct crypto_template *tmpl, struct rtattr **tb)
128{
129	struct shash_instance *inst;
130	struct crypto_cipher_spawn *spawn;
131	struct crypto_alg *alg;
132	u32 mask;
133	int err;
134
135	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SHASH, &mask);
136	if (err)
137		return err;
138
139	inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
140	if (!inst)
141		return -ENOMEM;
142	spawn = shash_instance_ctx(inst);
143
144	err = crypto_grab_cipher(spawn, shash_crypto_instance(inst),
145				 crypto_attr_alg_name(tb[1]), 0, mask);
146	if (err)
147		goto err_free_inst;
148	alg = crypto_spawn_cipher_alg(spawn);
149
150	err = -EINVAL;
151	if (alg->cra_blocksize != XCBC_BLOCKSIZE)
152		goto err_free_inst;
153
154	err = crypto_inst_setname(shash_crypto_instance(inst), tmpl->name, alg);
155	if (err)
156		goto err_free_inst;
157
158	inst->alg.base.cra_priority = alg->cra_priority;
159	inst->alg.base.cra_blocksize = alg->cra_blocksize;
160	inst->alg.base.cra_ctxsize = sizeof(struct xcbc_tfm_ctx) +
161				     alg->cra_blocksize * 2;
162	inst->alg.base.cra_flags = CRYPTO_AHASH_ALG_BLOCK_ONLY |
163				   CRYPTO_AHASH_ALG_FINAL_NONZERO;
164
165	inst->alg.digestsize = alg->cra_blocksize;
166	inst->alg.descsize = alg->cra_blocksize;
167
168	inst->alg.base.cra_init = xcbc_init_tfm;
169	inst->alg.base.cra_exit = xcbc_exit_tfm;
170
171	inst->alg.init = crypto_xcbc_digest_init;
172	inst->alg.update = crypto_xcbc_digest_update;
173	inst->alg.finup = crypto_xcbc_digest_finup;
174	inst->alg.setkey = crypto_xcbc_digest_setkey;
175
176	inst->free = shash_free_singlespawn_instance;
177
178	err = shash_register_instance(tmpl, inst);
179	if (err) {
180err_free_inst:
181		shash_free_singlespawn_instance(inst);
182	}
183	return err;
184}
185
186static struct crypto_template crypto_xcbc_tmpl = {
187	.name = "xcbc",
188	.create = xcbc_create,
189	.module = THIS_MODULE,
190};
191
192static int __init crypto_xcbc_module_init(void)
193{
194	return crypto_register_template(&crypto_xcbc_tmpl);
195}
196
197static void __exit crypto_xcbc_module_exit(void)
198{
199	crypto_unregister_template(&crypto_xcbc_tmpl);
200}
201
202module_init(crypto_xcbc_module_init);
203module_exit(crypto_xcbc_module_exit);
204
205MODULE_LICENSE("GPL");
206MODULE_DESCRIPTION("XCBC keyed hash algorithm");
207MODULE_ALIAS_CRYPTO("xcbc");
208MODULE_IMPORT_NS("CRYPTO_INTERNAL");