[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;
	}

	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;
	}

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

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

	if (req->dst_len < mpi_get_size(pkey->n)) {
		req->dst_len = mpi_get_size(pkey->n);
		ret = -EOVERFLOW;
		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 <[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
22287b0b TS	100	ret = -ENOMEM;
	101	m = mpi_read_raw_from_sgl(req->src, req->src_len);
	102	if (!m)
cfc2bb32	103	goto err_free_c;
cfc2bb32 TS	104
	105	ret = _rsa_enc(pkey, c, m);
	106	if (ret)
	107	goto err_free_m;
	108
22287b0b	109	ret = mpi_write_to_sgl(c, req->dst, &req->dst_len, &sign);
cfc2bb32 TS	110	if (ret)
	111	goto err_free_m;
	112
22287b0b	113	if (sign < 0)
cfc2bb32	114	ret = -EBADMSG;
cfc2bb32 TS	115
	116	err_free_m:
	117	mpi_free(m);
	118	err_free_c:
	119	mpi_free(c);
	120	return ret;
	121	}
	122
	123	static int rsa_dec(struct akcipher_request *req)
	124	{
	125	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	126	const struct rsa_key *pkey = rsa_get_key(tfm);
	127	MPI c, m = mpi_alloc(0);
	128	int ret = 0;
	129	int sign;
	130
	131	if (!m)
	132	return -ENOMEM;
	133
	134	if (unlikely(!pkey->n \|\| !pkey->d)) {
	135	ret = -EINVAL;
	136	goto err_free_m;
	137	}
	138
	139	if (req->dst_len < mpi_get_size(pkey->n)) {
	140	req->dst_len = mpi_get_size(pkey->n);
	141	ret = -EOVERFLOW;
	142	goto err_free_m;
	143	}
	144
22287b0b TS	145	ret = -ENOMEM;
	146	c = mpi_read_raw_from_sgl(req->src, req->src_len);
	147	if (!c)
cfc2bb32	148	goto err_free_m;
cfc2bb32 TS	149
	150	ret = _rsa_dec(pkey, m, c);
	151	if (ret)
	152	goto err_free_c;
	153
22287b0b	154	ret = mpi_write_to_sgl(m, req->dst, &req->dst_len, &sign);
cfc2bb32 TS	155	if (ret)
	156	goto err_free_c;
	157
22287b0b	158	if (sign < 0)
cfc2bb32	159	ret = -EBADMSG;
cfc2bb32 TS	160	err_free_c:
	161	mpi_free(c);
	162	err_free_m:
	163	mpi_free(m);
	164	return ret;
	165	}
	166
	167	static int rsa_sign(struct akcipher_request *req)
	168	{
	169	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	170	const struct rsa_key *pkey = rsa_get_key(tfm);
	171	MPI m, s = mpi_alloc(0);
	172	int ret = 0;
	173	int sign;
	174
	175	if (!s)
	176	return -ENOMEM;
	177
	178	if (unlikely(!pkey->n \|\| !pkey->d)) {
	179	ret = -EINVAL;
	180	goto err_free_s;
	181	}
	182
	183	if (req->dst_len < mpi_get_size(pkey->n)) {
	184	req->dst_len = mpi_get_size(pkey->n);
	185	ret = -EOVERFLOW;
	186	goto err_free_s;
	187	}
	188
22287b0b TS	189	ret = -ENOMEM;
	190	m = mpi_read_raw_from_sgl(req->src, req->src_len);
	191	if (!m)
cfc2bb32	192	goto err_free_s;
cfc2bb32 TS	193
	194	ret = _rsa_sign(pkey, s, m);
	195	if (ret)
	196	goto err_free_m;
	197
22287b0b	198	ret = mpi_write_to_sgl(s, req->dst, &req->dst_len, &sign);
cfc2bb32 TS	199	if (ret)
	200	goto err_free_m;
	201
22287b0b	202	if (sign < 0)
cfc2bb32	203	ret = -EBADMSG;
cfc2bb32 TS	204
	205	err_free_m:
	206	mpi_free(m);
	207	err_free_s:
	208	mpi_free(s);
	209	return ret;
	210	}
	211
	212	static int rsa_verify(struct akcipher_request *req)
	213	{
	214	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
	215	const struct rsa_key *pkey = rsa_get_key(tfm);
	216	MPI s, m = mpi_alloc(0);
	217	int ret = 0;
	218	int sign;
	219
	220	if (!m)
	221	return -ENOMEM;
	222
	223	if (unlikely(!pkey->n \|\| !pkey->e)) {
	224	ret = -EINVAL;
	225	goto err_free_m;
	226	}
	227
	228	if (req->dst_len < mpi_get_size(pkey->n)) {
	229	req->dst_len = mpi_get_size(pkey->n);
	230	ret = -EOVERFLOW;
	231	goto err_free_m;
	232	}
	233
22287b0b TS	234	ret = -ENOMEM;
22287b0b TS	235	s = mpi_read_raw_from_sgl(req->src, req->src_len);
cfc2bb32 TS	236	if (!s) {
	237	ret = -ENOMEM;
	238	goto err_free_m;
	239	}
	240
	241	ret = _rsa_verify(pkey, m, s);
	242	if (ret)
	243	goto err_free_s;
	244
22287b0b	245	ret = mpi_write_to_sgl(m, req->dst, &req->dst_len, &sign);
cfc2bb32 TS	246	if (ret)
	247	goto err_free_s;
	248
22287b0b	249	if (sign < 0)
cfc2bb32	250	ret = -EBADMSG;
cfc2bb32 TS	251
	252	err_free_s:
	253	mpi_free(s);
	254	err_free_m:
	255	mpi_free(m);
	256	return ret;
	257	}
	258
6e8ec66c TS	259	static int rsa_check_key_length(unsigned int len)
	260	{
	261	switch (len) {
	262	case 512:
	263	case 1024:
	264	case 1536:
	265	case 2048:
	266	case 3072:
	267	case 4096:
	268	return 0;
	269	}
	270
	271	return -EINVAL;
	272	}
	273
22287b0b TS	274	static int rsa_set_pub_key(struct crypto_akcipher tfm, const void key,
22287b0b TS	275	unsigned int keylen)
cfc2bb32 TS	276	{
cfc2bb32 TS	277	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
6e8ec66c	278	int ret;
cfc2bb32	279
22287b0b	280	ret = rsa_parse_pub_key(pkey, key, keylen);
6e8ec66c TS	281	if (ret)
	282	return ret;
	283
	284	if (rsa_check_key_length(mpi_get_size(pkey->n) << 3)) {
	285	rsa_free_key(pkey);
	286	ret = -EINVAL;
	287	}
	288	return ret;
cfc2bb32 TS	289	}
cfc2bb32 TS	290
22287b0b TS	291	static int rsa_set_priv_key(struct crypto_akcipher tfm, const void key,
	292	unsigned int keylen)
	293	{
	294	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
	295	int ret;
	296
	297	ret = rsa_parse_priv_key(pkey, key, keylen);
	298	if (ret)
	299	return ret;
	300
	301	if (rsa_check_key_length(mpi_get_size(pkey->n) << 3)) {
	302	rsa_free_key(pkey);
	303	ret = -EINVAL;
	304	}
	305	return ret;
	306	}
	307
	308	static int rsa_max_size(struct crypto_akcipher *tfm)
	309	{
	310	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
	311
	312	return pkey->n ? mpi_get_size(pkey->n) : -EINVAL;
	313	}
	314
cfc2bb32 TS	315	static void rsa_exit_tfm(struct crypto_akcipher *tfm)
	316	{
	317	struct rsa_key *pkey = akcipher_tfm_ctx(tfm);
	318
	319	rsa_free_key(pkey);
	320	}
	321
	322	static struct akcipher_alg rsa = {
	323	.encrypt = rsa_enc,
	324	.decrypt = rsa_dec,
	325	.sign = rsa_sign,
	326	.verify = rsa_verify,
22287b0b TS	327	.set_priv_key = rsa_set_priv_key,
	328	.set_pub_key = rsa_set_pub_key,
	329	.max_size = rsa_max_size,
cfc2bb32 TS	330	.exit = rsa_exit_tfm,
	331	.base = {
	332	.cra_name = "rsa",
	333	.cra_driver_name = "rsa-generic",
	334	.cra_priority = 100,
	335	.cra_module = THIS_MODULE,
	336	.cra_ctxsize = sizeof(struct rsa_key),
	337	},
	338	};
	339
	340	static int rsa_init(void)
	341	{
	342	return crypto_register_akcipher(&rsa);
	343	}
	344
	345	static void rsa_exit(void)
	346	{
	347	crypto_unregister_akcipher(&rsa);
	348	}
	349
	350	module_init(rsa_init);
	351	module_exit(rsa_exit);
	352	MODULE_ALIAS_CRYPTO("rsa");
	353	MODULE_LICENSE("GPL");
	354	MODULE_DESCRIPTION("RSA generic algorithm");