1/*
2 * ECB: Electronic CodeBook mode
3 *
4 * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License as published by the Free
8 * Software Foundation; either version 2 of the License, or (at your option)
9 * any later version.
10 *
11 */
12
13#include <crypto/algapi.h>
14#include <linux/err.h>
15#include <linux/init.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/scatterlist.h>
19#include <linux/slab.h>
20
21struct crypto_ecb_ctx {
22	struct crypto_cipher *child;
23};
24
25static int crypto_ecb_setkey(struct crypto_tfm *parent, const u8 *key,
26			     unsigned int keylen)
27{
28	struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(parent);
29	struct crypto_cipher *child = ctx->child;
30	int err;
31
32	crypto_cipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
33	crypto_cipher_set_flags(child, crypto_tfm_get_flags(parent) &
34				       CRYPTO_TFM_REQ_MASK);
35	err = crypto_cipher_setkey(child, key, keylen);
36	crypto_tfm_set_flags(parent, crypto_cipher_get_flags(child) &
37				     CRYPTO_TFM_RES_MASK);
38	return err;
39}
40
41static int crypto_ecb_crypt(struct blkcipher_desc *desc,
42			    struct blkcipher_walk *walk,
43			    struct crypto_cipher *tfm,
44			    void (*fn)(struct crypto_tfm *, u8 *, const u8 *))
45{
46	int bsize = crypto_cipher_blocksize(tfm);
47	unsigned int nbytes;
48	int err;
49
50	err = blkcipher_walk_virt(desc, walk);
51
52	while ((nbytes = walk->nbytes)) {
53		u8 *wsrc = walk->src.virt.addr;
54		u8 *wdst = walk->dst.virt.addr;
55
56		do {
57			fn(crypto_cipher_tfm(tfm), wdst, wsrc);
58
59			wsrc += bsize;
60			wdst += bsize;
61		} while ((nbytes -= bsize) >= bsize);
62
63		err = blkcipher_walk_done(desc, walk, nbytes);
64	}
65
66	return err;
67}
68
69static int crypto_ecb_encrypt(struct blkcipher_desc *desc,
70			      struct scatterlist *dst, struct scatterlist *src,
71			      unsigned int nbytes)
72{
73	struct blkcipher_walk walk;
74	struct crypto_blkcipher *tfm = desc->tfm;
75	struct crypto_ecb_ctx *ctx = crypto_blkcipher_ctx(tfm);
76	struct crypto_cipher *child = ctx->child;
77
78	blkcipher_walk_init(&walk, dst, src, nbytes);
79	return crypto_ecb_crypt(desc, &walk, child,
80				crypto_cipher_alg(child)->cia_encrypt);
81}
82
83static int crypto_ecb_decrypt(struct blkcipher_desc *desc,
84			      struct scatterlist *dst, struct scatterlist *src,
85			      unsigned int nbytes)
86{
87	struct blkcipher_walk walk;
88	struct crypto_blkcipher *tfm = desc->tfm;
89	struct crypto_ecb_ctx *ctx = crypto_blkcipher_ctx(tfm);
90	struct crypto_cipher *child = ctx->child;
91
92	blkcipher_walk_init(&walk, dst, src, nbytes);
93	return crypto_ecb_crypt(desc, &walk, child,
94				crypto_cipher_alg(child)->cia_decrypt);
95}
96
97static int crypto_ecb_init_tfm(struct crypto_tfm *tfm)
98{
99	struct crypto_instance *inst = (void *)tfm->__crt_alg;
100	struct crypto_spawn *spawn = crypto_instance_ctx(inst);
101	struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(tfm);
102	struct crypto_cipher *cipher;
103
104	cipher = crypto_spawn_cipher(spawn);
105	if (IS_ERR(cipher))
106		return PTR_ERR(cipher);
107
108	ctx->child = cipher;
109	return 0;
110}
111
112static void crypto_ecb_exit_tfm(struct crypto_tfm *tfm)
113{
114	struct crypto_ecb_ctx *ctx = crypto_tfm_ctx(tfm);
115	crypto_free_cipher(ctx->child);
116}
117
118static struct crypto_instance *crypto_ecb_alloc(struct rtattr **tb)
119{
120	struct crypto_instance *inst;
121	struct crypto_alg *alg;
122	int err;
123
124	err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_BLKCIPHER);
125	if (err)
126		return ERR_PTR(err);
127
128	alg = crypto_get_attr_alg(tb, CRYPTO_ALG_TYPE_CIPHER,
129				  CRYPTO_ALG_TYPE_MASK);
130	if (IS_ERR(alg))
131		return ERR_CAST(alg);
132
133	inst = crypto_alloc_instance("ecb", alg);
134	if (IS_ERR(inst))
135		goto out_put_alg;
136
137	inst->alg.cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER;
138	inst->alg.cra_priority = alg->cra_priority;
139	inst->alg.cra_blocksize = alg->cra_blocksize;
140	inst->alg.cra_alignmask = alg->cra_alignmask;
141	inst->alg.cra_type = &crypto_blkcipher_type;
142
143	inst->alg.cra_blkcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
144	inst->alg.cra_blkcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
145
146	inst->alg.cra_ctxsize = sizeof(struct crypto_ecb_ctx);
147
148	inst->alg.cra_init = crypto_ecb_init_tfm;
149	inst->alg.cra_exit = crypto_ecb_exit_tfm;
150
151	inst->alg.cra_blkcipher.setkey = crypto_ecb_setkey;
152	inst->alg.cra_blkcipher.encrypt = crypto_ecb_encrypt;
153	inst->alg.cra_blkcipher.decrypt = crypto_ecb_decrypt;
154
155out_put_alg:
156	crypto_mod_put(alg);
157	return inst;
158}
159
160static void crypto_ecb_free(struct crypto_instance *inst)
161{
162	crypto_drop_spawn(crypto_instance_ctx(inst));
163	kfree(inst);
164}
165
166static struct crypto_template crypto_ecb_tmpl = {
167	.name = "ecb",
168	.alloc = crypto_ecb_alloc,
169	.free = crypto_ecb_free,
170	.module = THIS_MODULE,
171};
172
173static int __init crypto_ecb_module_init(void)
174{
175	return crypto_register_template(&crypto_ecb_tmpl);
176}
177
178static void __exit crypto_ecb_module_exit(void)
179{
180	crypto_unregister_template(&crypto_ecb_tmpl);
181}
182
183module_init(crypto_ecb_module_init);
184module_exit(crypto_ecb_module_exit);
185
186MODULE_LICENSE("GPL");
187MODULE_DESCRIPTION("ECB block cipher algorithm");
188MODULE_ALIAS_CRYPTO("ecb");
189