[linux.git] / crypto / rsa.c

/* RSA asymmetric public-key algorithm [RFC3447]
 *
 * Copyright (c) 2015, Intel Corporation
 * Authors: Tadeusz Struk <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public Licence
 * as published by the Free Software Foundation; either version
 * 2 of the Licence, or (at your option) any later version.
 */

#include <linux/module.h>
#include <crypto/internal/rsa.h>
#include <crypto/internal/akcipher.h>
#include <crypto/akcipher.h>

/*
 * RSAEP function [RFC3447 sec 5.1.1]
 * c = m^e mod n;
 */
static int _rsa_enc(const struct rsa_key *key, MPI c, MPI m)
{
	/* (1) Validate 0 <= m < n */
	if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
		return -EINVAL;

	/* (2) c = m^e mod n */
	return mpi_powm(c, m, key->e, key->n);
}

/*
 * RSADP function [RFC3447 sec 5.1.2]
 * m = c^d mod n;
 */
static int _rsa_dec(const struct rsa_key *key, MPI m, MPI c)
{
	/* (1) Validate 0 <= c < n */
	if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0)
		return -EINVAL;

	/* (2) m = c^d mod n */
	return mpi_powm(m, c, key->d, key->n);
}

/*
 * RSASP1 function [RFC3447 sec 5.2.1]
 * s = m^d mod n
 */
static int _rsa_sign(const struct rsa_key *key, MPI s, MPI m)
{
	/* (1) Validate 0 <= m < n */
	if (mpi_cmp_ui(m, 0) < 0 || mpi_cmp(m, key->n) >= 0)
		return -EINVAL;

	/* (2) s = m^d mod n */
	return mpi_powm(s, m, key->d, key->n);
}

/*
 * RSAVP1 function [RFC3447 sec 5.2.2]
 * m = s^e mod n;
 */
static int _rsa_verify(const struct rsa_key *key, MPI m, MPI s)
{
	/* (1) Validate 0 <= s < n */
	if (mpi_cmp_ui(s, 0) < 0 || mpi_cmp(s, key->n) >= 0)
		return -EINVAL;

	/* (2) m = s^e mod n */
	return mpi_powm(m, s, key->e, key->n);
}

static inline struct rsa_key *rsa_get_key(struct crypto_akcipher *tfm)
{
	return akcipher_tfm_ctx(tfm);
}

static int rsa_enc(struct akcipher_request *req)
{
	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	const struct rsa_key *pkey = rsa_get_key(tfm);
	MPI m, c = mpi_alloc(0);
	int ret = 0;
	int sign;

	if (!c)
		return -ENOMEM;

	if (unlikely(!pkey->n || !pkey->e)) {
		ret = -EINVAL;
		goto err_free_c;
	}

	if (req->dst_len < mpi_get_size(pkey->n)) {
		req->dst_len = mpi_get_size(pkey->n);
		ret = -EOVERFLOW;
		goto err_free_c;
	}

	m = mpi_read_raw_data(req->src, req->src_len);
	if (!m) {
		ret = -ENOMEM;
		goto err_free_c;
	}

	ret = _rsa_enc(pkey, c, m);
	if (ret)
		goto err_free_m;

	ret = mpi_read_buffer(c, req->dst, req->dst_len, &req->dst_len, &sign);
	if (ret)
		goto err_free_m;

	if (sign < 0) {
		ret = -EBADMSG;
		goto err_free_m;
	}

err_free_m:
	mpi_free(m);
err_free_c:
	mpi_free(c);
	return ret;
}

static int rsa_dec(struct akcipher_request *req)
{
	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	const struct rsa_key *pkey = rsa_get_key(tfm);
	MPI c, m = mpi_alloc(0);
	int ret = 0;
	int sign;

	if (!m)
		return -ENOMEM;

	if (unlikely(!pkey->n || !pkey->d)) {
		ret = -EINVAL;
		goto err_free_m;
	}

	if (req->dst_len < mpi_get_size(pkey->n)) {
		req->dst_len = mpi_get_size(pkey->n);
		ret = -EOVERFLOW;
		goto err_free_m;
	}

	c = mpi_read_raw_data(req->src, req->src_len);
	if (!c) {
		ret = -ENOMEM;
		goto err_free_m;
	}

	ret = _rsa_dec(pkey, m, c);
	if (ret)
		goto err_free_c;

	ret = mpi_read_buffer(m, req->dst, req->dst_len, &req->dst_len, &sign);
	if (ret)
		goto err_free_c;

	if (sign < 0) {
		ret = -EBADMSG;
		goto err_free_c;
	}

err_free_c:
	mpi_free(c);
err_free_m:
	mpi_free(m);
	return ret;
}

static int rsa_sign(struct akcipher_request *req)
{
	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	const struct rsa_key *pkey = rsa_get_key(tfm);
	MPI m, s = mpi_alloc(0);
	int ret = 0;
	int sign;

	if (!s)
		return -ENOMEM;

	if (unlikely(!pkey->n || !pkey->d)) {
		ret = -EINVAL;
		goto err_free_s;
	}

	if (req->dst_len < mpi_get_size(pkey->n)) {
		req->dst_len = mpi_get_size(pkey->n);
		ret = -EOVERFLOW;
		goto err_free_s;
	}

	m = mpi_read_raw_data(req->src, req->src_len);
	if (!m) {
		ret = -ENOMEM;
		goto err_free_s;
	}

	ret = _rsa_sign(pkey, s, m);
	if (ret)
		goto err_free_m;

	ret = mpi_read_buffer(s, req->dst, req->dst_len, &req->dst_len, &sign);
	if (ret)
		goto err_free_m;

	if (sign < 0) {
		ret = -EBADMSG;
		goto err_free_m;
	}

err_free_m:
	mpi_free(m);
err_free_s:
	mpi_free(s);
	return ret;
}

static int rsa_verify(struct akcipher_request *req)
{
	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	const struct rsa_key *pkey = rsa_get_key(tfm);
	MPI s, m = mpi_alloc(0);
	int ret = 0;
	int sign;

	if (!m)
		return -ENOMEM;

	if (unlikely(!pkey->n || !pkey->e)) {
		ret = -EINVAL;
		goto err_free_m;
	}

	if (req->dst_len < mpi_get_size(pkey->n)) {
		req->dst_len = mpi_get_size(pkey->n);
		ret = -EOVERFLOW;
		goto err_free_m;
	}

	s = mpi_read_raw_data(req->src, req->src_len);
	if (!s) {
		ret = -ENOMEM;
		goto err_free_m;
	}

	ret = _rsa_verify(pkey, m, s);
	if (ret)
		goto err_free_s;

	ret = mpi_read_buffer(m, req->dst, req->dst_len, &req->dst_len, &sign);
	if (ret)
		goto err_free_s;

	if (sign < 0) {
		ret = -EBADMSG;
		goto err_free_s;
	}

err_free_s:
	mpi_free(s);
err_free_m:
	mpi_free(m);
	return ret;
}

static int rsa_check_key_length(unsigned int len)
{
	switch (len) {
	case 512:
	case 1024:
	case 1536:
	case 2048:
	case 3072:
	case 4096:
		return 0;
	}

	return -EINVAL;
}

static int rsa_setkey(struct crypto_akcipher *tfm, const void *key,
		      unsigned int keylen)
{
	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
	int ret;

	ret = rsa_parse_key(pkey, key, keylen);
	if (ret)
		return ret;

	if (rsa_check_key_length(mpi_get_size(pkey->n) << 3)) {
		rsa_free_key(pkey);
		ret = -EINVAL;
	}
	return ret;
}

static void rsa_exit_tfm(struct crypto_akcipher *tfm)
{
	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);

	rsa_free_key(pkey);
}

static struct akcipher_alg rsa = {
	.encrypt = rsa_enc,
	.decrypt = rsa_dec,
	.sign = rsa_sign,
	.verify = rsa_verify,
	.setkey = rsa_setkey,
	.exit = rsa_exit_tfm,
	.base = {
		.cra_name = "rsa",
		.cra_driver_name = "rsa-generic",
		.cra_priority = 100,
		.cra_module = THIS_MODULE,
		.cra_ctxsize = sizeof(struct rsa_key),
	},
};

static int rsa_init(void)
{
	return crypto_register_akcipher(&rsa);
}

static void rsa_exit(void)
{
	crypto_unregister_akcipher(&rsa);
}

module_init(rsa_init);
module_exit(rsa_exit);
MODULE_ALIAS_CRYPTO("rsa");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("RSA generic algorithm");
Commit	Line	Data
cfc2bb32 TS	1	/* RSA asymmetric public-key algorithm [RFC3447]
	2	*
	3	* Copyright (c) 2015, Intel Corporation
	4	* Authors: Tadeusz Struk <[email protected]>
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public Licence
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the Licence, or (at your option) any later version.
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <crypto/internal/rsa.h>
	14	#include <crypto/internal/akcipher.h>
	15	#include <crypto/akcipher.h>
	16
	17	/*
	18	* RSAEP function [RFC3447 sec 5.1.1]
	19	* c = m^e mod n;
	20	*/
	21	static int _rsa_enc(const struct rsa_key *key, MPI c, MPI m)
	22	{
	23	/* (1) Validate 0 <= m < n */
	24	if (mpi_cmp_ui(m, 0) < 0 \|\| mpi_cmp(m, key->n) >= 0)
	25	return -EINVAL;
	26
	27	/* (2) c = m^e mod n */
	28	return mpi_powm(c, m, key->e, key->n);
	29	}
	30
	31	/*
	32	* RSADP function [RFC3447 sec 5.1.2]
	33	* m = c^d mod n;
	34	*/
	35	static int _rsa_dec(const struct rsa_key *key, MPI m, MPI c)
	36	{
	37	/* (1) Validate 0 <= c < n */
	38	if (mpi_cmp_ui(c, 0) < 0 \|\| mpi_cmp(c, key->n) >= 0)
	39	return -EINVAL;
	40
	41	/* (2) m = c^d mod n */
	42	return mpi_powm(m, c, key->d, key->n);
	43	}
	44
	45	/*
	46	* RSASP1 function [RFC3447 sec 5.2.1]
	47	* s = m^d mod n
	48	*/
	49	static int _rsa_sign(const struct rsa_key *key, MPI s, MPI m)
	50	{
	51	/* (1) Validate 0 <= m < n */
	52	if (mpi_cmp_ui(m, 0) < 0 \|\| mpi_cmp(m, key->n) >= 0)
	53	return -EINVAL;
	54
	55	/* (2) s = m^d mod n */
	56	return mpi_powm(s, m, key->d, key->n);
	57	}
	58
	59	/*
	60	* RSAVP1 function [RFC3447 sec 5.2.2]
	61	* m = s^e mod n;
	62	*/
	63	static int _rsa_verify(const struct rsa_key *key, MPI m, MPI s)
	64	{
65	/* (1) Validate 0 <= s < n */
66	if (mpi_cmp_ui(s, 0) < 0 \|\| mpi_cmp(s, key->n) >= 0)
67	return -EINVAL;
68
69	/* (2) m = s^e mod n */
70	return mpi_powm(m, s, key->e, key->n);
71	}
72
73	static inline struct rsa_key rsa_get_key(struct crypto_akcipher tfm)
74	{
75	return akcipher_tfm_ctx(tfm);
76	}
77
78	static int rsa_enc(struct akcipher_request *req)
79	{
80	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
81	const struct rsa_key *pkey = rsa_get_key(tfm);
82	MPI m, c = mpi_alloc(0);
83	int ret = 0;
84	int sign;
85
86	if (!c)
87	return -ENOMEM;
88
89	if (unlikely(!pkey->n \|\| !pkey->e)) {
90	ret = -EINVAL;
91	goto err_free_c;
92	}
93
94	if (req->dst_len < mpi_get_size(pkey->n)) {
95	req->dst_len = mpi_get_size(pkey->n);
96	ret = -EOVERFLOW;
97	goto err_free_c;
98	}
99
100	m = mpi_read_raw_data(req->src, req->src_len);
101	if (!m) {
102	ret = -ENOMEM;
103	goto err_free_c;
104	}
105
106	ret = _rsa_enc(pkey, c, m);
107	if (ret)
108	goto err_free_m;
109
110	ret = mpi_read_buffer(c, req->dst, req->dst_len, &req->dst_len, &sign);
111	if (ret)
112	goto err_free_m;
113
114	if (sign < 0) {
115	ret = -EBADMSG;
116	goto err_free_m;
117	}
118
119	err_free_m:
120	mpi_free(m);
121	err_free_c:
122	mpi_free(c);
123	return ret;
124	}
125
126	static int rsa_dec(struct akcipher_request *req)
127	{
128	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
129	const struct rsa_key *pkey = rsa_get_key(tfm);
130	MPI c, m = mpi_alloc(0);
131	int ret = 0;
132	int sign;
133
134	if (!m)
135	return -ENOMEM;
136
137	if (unlikely(!pkey->n \|\| !pkey->d)) {
138	ret = -EINVAL;
139	goto err_free_m;
140	}
141
142	if (req->dst_len < mpi_get_size(pkey->n)) {
143	req->dst_len = mpi_get_size(pkey->n);
144	ret = -EOVERFLOW;
145	goto err_free_m;
146	}
147
148	c = mpi_read_raw_data(req->src, req->src_len);
149	if (!c) {
150	ret = -ENOMEM;
151	goto err_free_m;
152	}
153
154	ret = _rsa_dec(pkey, m, c);
155	if (ret)
156	goto err_free_c;
157
158	ret = mpi_read_buffer(m, req->dst, req->dst_len, &req->dst_len, &sign);
159	if (ret)
160	goto err_free_c;
161
162	if (sign < 0) {
163	ret = -EBADMSG;
164	goto err_free_c;
165	}
166
167	err_free_c:
168	mpi_free(c);
169	err_free_m:
170	mpi_free(m);
171	return ret;
172	}
173
174	static int rsa_sign(struct akcipher_request *req)
175	{
176	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
177	const struct rsa_key *pkey = rsa_get_key(tfm);
178	MPI m, s = mpi_alloc(0);
179	int ret = 0;
180	int sign;
181
182	if (!s)
183	return -ENOMEM;
184
185	if (unlikely(!pkey->n \|\| !pkey->d)) {
186	ret = -EINVAL;
187	goto err_free_s;
188	}
189
190	if (req->dst_len < mpi_get_size(pkey->n)) {
191	req->dst_len = mpi_get_size(pkey->n);
192	ret = -EOVERFLOW;
193	goto err_free_s;
194	}
195
196	m = mpi_read_raw_data(req->src, req->src_len);
197	if (!m) {
198	ret = -ENOMEM;
199	goto err_free_s;
200	}
201
202	ret = _rsa_sign(pkey, s, m);
203	if (ret)
204	goto err_free_m;
205
206	ret = mpi_read_buffer(s, req->dst, req->dst_len, &req->dst_len, &sign);
207	if (ret)
208	goto err_free_m;
209
210	if (sign < 0) {
211	ret = -EBADMSG;
212	goto err_free_m;
213	}
214
215	err_free_m:
216	mpi_free(m);
217	err_free_s:
218	mpi_free(s);
219	return ret;
220	}
221
222	static int rsa_verify(struct akcipher_request *req)
223	{
224	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
225	const struct rsa_key *pkey = rsa_get_key(tfm);
226	MPI s, m = mpi_alloc(0);
227	int ret = 0;
228	int sign;
229
230	if (!m)
231	return -ENOMEM;
232
233	if (unlikely(!pkey->n \|\| !pkey->e)) {
234	ret = -EINVAL;
235	goto err_free_m;
236	}
237
238	if (req->dst_len < mpi_get_size(pkey->n)) {
239	req->dst_len = mpi_get_size(pkey->n);
240	ret = -EOVERFLOW;
241	goto err_free_m;
242	}
243
244	s = mpi_read_raw_data(req->src, req->src_len);
245	if (!s) {
246	ret = -ENOMEM;
247	goto err_free_m;
248	}
249
250	ret = _rsa_verify(pkey, m, s);
251	if (ret)
252	goto err_free_s;
253
254	ret = mpi_read_buffer(m, req->dst, req->dst_len, &req->dst_len, &sign);
255	if (ret)
256	goto err_free_s;
257
258	if (sign < 0) {
259	ret = -EBADMSG;
260	goto err_free_s;
261	}
262
263	err_free_s:
264	mpi_free(s);
265	err_free_m:
266	mpi_free(m);
267	return ret;
268	}
269
6e8ec66c TS	270	static int rsa_check_key_length(unsigned int len)
	271	{
	272	switch (len) {
	273	case 512:
	274	case 1024:
	275	case 1536:
	276	case 2048:
	277	case 3072:
	278	case 4096:
	279	return 0;
	280	}
	281
	282	return -EINVAL;
	283	}
	284
cfc2bb32 TS	285	static int rsa_setkey(struct crypto_akcipher tfm, const void key,
	286	unsigned int keylen)
	287	{
	288	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
6e8ec66c	289	int ret;
cfc2bb32	290
6e8ec66c TS	291	ret = rsa_parse_key(pkey, key, keylen);
	292	if (ret)
	293	return ret;
	294
	295	if (rsa_check_key_length(mpi_get_size(pkey->n) << 3)) {
	296	rsa_free_key(pkey);
	297	ret = -EINVAL;
	298	}
	299	return ret;
cfc2bb32 TS	300	}
	301
	302	static void rsa_exit_tfm(struct crypto_akcipher *tfm)
	303	{
	304	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
	305
	306	rsa_free_key(pkey);
	307	}
	308
	309	static struct akcipher_alg rsa = {
	310	.encrypt = rsa_enc,
	311	.decrypt = rsa_dec,
	312	.sign = rsa_sign,
	313	.verify = rsa_verify,
	314	.setkey = rsa_setkey,
	315	.exit = rsa_exit_tfm,
	316	.base = {
	317	.cra_name = "rsa",
	318	.cra_driver_name = "rsa-generic",
	319	.cra_priority = 100,
	320	.cra_module = THIS_MODULE,
	321	.cra_ctxsize = sizeof(struct rsa_key),
	322	},
	323	};
	324
	325	static int rsa_init(void)
	326	{
	327	return crypto_register_akcipher(&rsa);
	328	}
	329
	330	static void rsa_exit(void)
	331	{
	332	crypto_unregister_akcipher(&rsa);
	333	}
	334
	335	module_init(rsa_init);
	336	module_exit(rsa_exit);
	337	MODULE_ALIAS_CRYPTO("rsa");
	338	MODULE_LICENSE("GPL");
	339	MODULE_DESCRIPTION("RSA generic algorithm");