[mirror_ubuntu-zesty-kernel.git] / crypto / rsa.c

/* RSA asymmetric public-key algorithm [RFC3447]
 *
 * Copyright (c) 2015, Intel Corporation
 * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
 *
 * 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;
	}

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

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

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

	if (sign < 0)
		ret = -EBADMSG;

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;
	}

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

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

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

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

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

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

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

	if (sign < 0)
		ret = -EBADMSG;

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;
	}

	ret = -ENOMEM;
	s = mpi_read_raw_from_sgl(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_write_to_sgl(m, req->dst, &req->dst_len, &sign);
	if (ret)
		goto err_free_s;

	if (sign < 0)
		ret = -EBADMSG;

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

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

	ret = rsa_parse_priv_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 int rsa_max_size(struct crypto_akcipher *tfm)
{
	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);

	return pkey->n ? mpi_get_size(pkey->n) : -EINVAL;
}

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,
	.set_priv_key = rsa_set_priv_key,
	.set_pub_key = rsa_set_pub_key,
	.max_size = rsa_max_size,
	.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 <tadeusz.struk@intel.com>
	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
22287b0b TS	94	ret = -ENOMEM;
	95	m = mpi_read_raw_from_sgl(req->src, req->src_len);
	96	if (!m)
cfc2bb32	97	goto err_free_c;
cfc2bb32 TS	98
	99	ret = _rsa_enc(pkey, c, m);
	100	if (ret)
	101	goto err_free_m;
	102
22287b0b	103	ret = mpi_write_to_sgl(c, req->dst, &req->dst_len, &sign);
cfc2bb32 TS	104	if (ret)
	105	goto err_free_m;
	106
22287b0b	107	if (sign < 0)
cfc2bb32	108	ret = -EBADMSG;
cfc2bb32 TS	109
	110	err_free_m:
	111	mpi_free(m);
	112	err_free_c:
	113	mpi_free(c);
	114	return ret;
	115	}
	116
	117	static int rsa_dec(struct akcipher_request *req)
	118	{
	119	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	120	const struct rsa_key *pkey = rsa_get_key(tfm);
	121	MPI c, m = mpi_alloc(0);
	122	int ret = 0;
	123	int sign;
	124
	125	if (!m)
	126	return -ENOMEM;
	127
	128	if (unlikely(!pkey->n \|\| !pkey->d)) {
	129	ret = -EINVAL;
	130	goto err_free_m;
	131	}
	132
22287b0b TS	133	ret = -ENOMEM;
	134	c = mpi_read_raw_from_sgl(req->src, req->src_len);
	135	if (!c)
cfc2bb32	136	goto err_free_m;
cfc2bb32 TS	137
	138	ret = _rsa_dec(pkey, m, c);
	139	if (ret)
	140	goto err_free_c;
	141
22287b0b	142	ret = mpi_write_to_sgl(m, req->dst, &req->dst_len, &sign);
cfc2bb32 TS	143	if (ret)
	144	goto err_free_c;
	145
22287b0b	146	if (sign < 0)
cfc2bb32	147	ret = -EBADMSG;
cfc2bb32 TS	148	err_free_c:
	149	mpi_free(c);
	150	err_free_m:
	151	mpi_free(m);
	152	return ret;
	153	}
	154
	155	static int rsa_sign(struct akcipher_request *req)
	156	{
	157	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	158	const struct rsa_key *pkey = rsa_get_key(tfm);
	159	MPI m, s = mpi_alloc(0);
	160	int ret = 0;
	161	int sign;
	162
	163	if (!s)
	164	return -ENOMEM;
	165
	166	if (unlikely(!pkey->n \|\| !pkey->d)) {
	167	ret = -EINVAL;
	168	goto err_free_s;
	169	}
	170
22287b0b TS	171	ret = -ENOMEM;
	172	m = mpi_read_raw_from_sgl(req->src, req->src_len);
	173	if (!m)
cfc2bb32	174	goto err_free_s;
cfc2bb32 TS	175
	176	ret = _rsa_sign(pkey, s, m);
	177	if (ret)
	178	goto err_free_m;
	179
22287b0b	180	ret = mpi_write_to_sgl(s, req->dst, &req->dst_len, &sign);
cfc2bb32 TS	181	if (ret)
	182	goto err_free_m;
	183
22287b0b	184	if (sign < 0)
cfc2bb32	185	ret = -EBADMSG;
cfc2bb32 TS	186
	187	err_free_m:
	188	mpi_free(m);
	189	err_free_s:
	190	mpi_free(s);
	191	return ret;
	192	}
	193
	194	static int rsa_verify(struct akcipher_request *req)
	195	{
	196	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	197	const struct rsa_key *pkey = rsa_get_key(tfm);
	198	MPI s, m = mpi_alloc(0);
	199	int ret = 0;
	200	int sign;
	201
	202	if (!m)
	203	return -ENOMEM;
	204
	205	if (unlikely(!pkey->n \|\| !pkey->e)) {
	206	ret = -EINVAL;
	207	goto err_free_m;
	208	}
	209
22287b0b TS	210	ret = -ENOMEM;
22287b0b TS	211	s = mpi_read_raw_from_sgl(req->src, req->src_len);
cfc2bb32 TS	212	if (!s) {
	213	ret = -ENOMEM;
	214	goto err_free_m;
	215	}
	216
	217	ret = _rsa_verify(pkey, m, s);
	218	if (ret)
	219	goto err_free_s;
	220
22287b0b	221	ret = mpi_write_to_sgl(m, req->dst, &req->dst_len, &sign);
cfc2bb32 TS	222	if (ret)
	223	goto err_free_s;
	224
22287b0b	225	if (sign < 0)
cfc2bb32	226	ret = -EBADMSG;
cfc2bb32 TS	227
	228	err_free_s:
	229	mpi_free(s);
	230	err_free_m:
	231	mpi_free(m);
	232	return ret;
	233	}
	234
6e8ec66c TS	235	static int rsa_check_key_length(unsigned int len)
	236	{
	237	switch (len) {
	238	case 512:
	239	case 1024:
	240	case 1536:
	241	case 2048:
	242	case 3072:
	243	case 4096:
	244	return 0;
	245	}
	246
	247	return -EINVAL;
	248	}
	249
22287b0b TS	250	static int rsa_set_pub_key(struct crypto_akcipher tfm, const void key,
22287b0b TS	251	unsigned int keylen)
cfc2bb32 TS	252	{
cfc2bb32 TS	253	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
6e8ec66c	254	int ret;
cfc2bb32	255
22287b0b	256	ret = rsa_parse_pub_key(pkey, key, keylen);
6e8ec66c TS	257	if (ret)
	258	return ret;
	259
	260	if (rsa_check_key_length(mpi_get_size(pkey->n) << 3)) {
	261	rsa_free_key(pkey);
	262	ret = -EINVAL;
	263	}
	264	return ret;
cfc2bb32 TS	265	}
cfc2bb32 TS	266
22287b0b TS	267	static int rsa_set_priv_key(struct crypto_akcipher tfm, const void key,
	268	unsigned int keylen)
	269	{
	270	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
	271	int ret;
	272
	273	ret = rsa_parse_priv_key(pkey, key, keylen);
	274	if (ret)
	275	return ret;
	276
	277	if (rsa_check_key_length(mpi_get_size(pkey->n) << 3)) {
	278	rsa_free_key(pkey);
	279	ret = -EINVAL;
	280	}
	281	return ret;
	282	}
	283
	284	static int rsa_max_size(struct crypto_akcipher *tfm)
	285	{
	286	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
	287
	288	return pkey->n ? mpi_get_size(pkey->n) : -EINVAL;
	289	}
	290
cfc2bb32 TS	291	static void rsa_exit_tfm(struct crypto_akcipher *tfm)
	292	{
	293	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
	294
	295	rsa_free_key(pkey);
	296	}
	297
	298	static struct akcipher_alg rsa = {
	299	.encrypt = rsa_enc,
	300	.decrypt = rsa_dec,
	301	.sign = rsa_sign,
	302	.verify = rsa_verify,
22287b0b TS	303	.set_priv_key = rsa_set_priv_key,
	304	.set_pub_key = rsa_set_pub_key,
	305	.max_size = rsa_max_size,
cfc2bb32 TS	306	.exit = rsa_exit_tfm,
	307	.base = {
	308	.cra_name = "rsa",
	309	.cra_driver_name = "rsa-generic",
	310	.cra_priority = 100,
	311	.cra_module = THIS_MODULE,
	312	.cra_ctxsize = sizeof(struct rsa_key),
	313	},
	314	};
	315
	316	static int rsa_init(void)
	317	{
	318	return crypto_register_akcipher(&rsa);
	319	}
	320
	321	static void rsa_exit(void)
	322	{
	323	crypto_unregister_akcipher(&rsa);
	324	}
	325
	326	module_init(rsa_init);
	327	module_exit(rsa_exit);
	328	MODULE_ALIAS_CRYPTO("rsa");
	329	MODULE_LICENSE("GPL");
	330	MODULE_DESCRIPTION("RSA generic algorithm");