[linux-2.6-block.git] / crypto / rsa.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* RSA asymmetric public-key algorithm [RFC3447]
 *
 * Copyright (c) 2015, Intel Corporation
 * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
 */

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

struct rsa_mpi_key {
	MPI n;
	MPI e;
	MPI d;
};

/*
 * RSAEP function [RFC3447 sec 5.1.1]
 * c = m^e mod n;
 */
static int _rsa_enc(const struct rsa_mpi_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_mpi_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);
}

static inline struct rsa_mpi_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_mpi_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_mpi_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 void rsa_free_mpi_key(struct rsa_mpi_key *key)
{
	mpi_free(key->d);
	mpi_free(key->e);
	mpi_free(key->n);
	key->d = NULL;
	key->e = NULL;
	key->n = NULL;
}

static int rsa_check_key_length(unsigned int len)
{
	switch (len) {
	case 512:
	case 1024:
	case 1536:
		if (fips_enabled)
			return -EINVAL;
		fallthrough;
	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_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
	struct rsa_key raw_key = {0};
	int ret;

	/* Free the old MPI key if any */
	rsa_free_mpi_key(mpi_key);

	ret = rsa_parse_pub_key(&raw_key, key, keylen);
	if (ret)
		return ret;

	mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
	if (!mpi_key->e)
		goto err;

	mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
	if (!mpi_key->n)
		goto err;

	if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
		rsa_free_mpi_key(mpi_key);
		return -EINVAL;
	}

	return 0;

err:
	rsa_free_mpi_key(mpi_key);
	return -ENOMEM;
}

static int rsa_set_priv_key(struct crypto_akcipher *tfm, const void *key,
			    unsigned int keylen)
{
	struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
	struct rsa_key raw_key = {0};
	int ret;

	/* Free the old MPI key if any */
	rsa_free_mpi_key(mpi_key);

	ret = rsa_parse_priv_key(&raw_key, key, keylen);
	if (ret)
		return ret;

	mpi_key->d = mpi_read_raw_data(raw_key.d, raw_key.d_sz);
	if (!mpi_key->d)
		goto err;

	mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
	if (!mpi_key->e)
		goto err;

	mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
	if (!mpi_key->n)
		goto err;

	if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
		rsa_free_mpi_key(mpi_key);
		return -EINVAL;
	}

	return 0;

err:
	rsa_free_mpi_key(mpi_key);
	return -ENOMEM;
}

static unsigned int rsa_max_size(struct crypto_akcipher *tfm)
{
	struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);

	return mpi_get_size(pkey->n);
}

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

	rsa_free_mpi_key(pkey);
}

static struct akcipher_alg rsa = {
	.encrypt = rsa_enc,
	.decrypt = rsa_dec,
	.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_mpi_key),
	},
};

static int rsa_init(void)
{
	int err;

	err = crypto_register_akcipher(&rsa);
	if (err)
		return err;

	err = crypto_register_template(&rsa_pkcs1pad_tmpl);
	if (err) {
		crypto_unregister_akcipher(&rsa);
		return err;
	}

	return 0;
}

static void rsa_exit(void)
{
	crypto_unregister_template(&rsa_pkcs1pad_tmpl);
	crypto_unregister_akcipher(&rsa);
}

subsys_initcall(rsa_init);
module_exit(rsa_exit);
MODULE_ALIAS_CRYPTO("rsa");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("RSA generic algorithm");
Commit	Line	Data
b4d0d230	1	// SPDX-License-Identifier: GPL-2.0-or-later
cfc2bb32 TS	2	/* RSA asymmetric public-key algorithm [RFC3447]
	3	*
	4	* Copyright (c) 2015, Intel Corporation
	5	* Authors: Tadeusz Struk <tadeusz.struk@intel.com>
cfc2bb32 TS	6	*/
cfc2bb32 TS	7
1ce1bacc	8	#include <linux/fips.h>
cfc2bb32	9	#include <linux/module.h>
5a7de973	10	#include <linux/mpi.h>
cfc2bb32 TS	11	#include <crypto/internal/rsa.h>
	12	#include <crypto/internal/akcipher.h>
	13	#include <crypto/akcipher.h>
3d5b1ecd	14	#include <crypto/algapi.h>
cfc2bb32	15
5a7de973 TA	16	struct rsa_mpi_key {
	17	MPI n;
	18	MPI e;
	19	MPI d;
	20	};
	21
cfc2bb32 TS	22	/*
	23	* RSAEP function [RFC3447 sec 5.1.1]
	24	* c = m^e mod n;
	25	*/
5a7de973	26	static int _rsa_enc(const struct rsa_mpi_key *key, MPI c, MPI m)
cfc2bb32 TS	27	{
	28	/* (1) Validate 0 <= m < n */
	29	if (mpi_cmp_ui(m, 0) < 0 \|\| mpi_cmp(m, key->n) >= 0)
	30	return -EINVAL;
	31
	32	/* (2) c = m^e mod n */
	33	return mpi_powm(c, m, key->e, key->n);
	34	}
	35
	36	/*
	37	* RSADP function [RFC3447 sec 5.1.2]
	38	* m = c^d mod n;
	39	*/
5a7de973	40	static int _rsa_dec(const struct rsa_mpi_key *key, MPI m, MPI c)
cfc2bb32 TS	41	{
	42	/* (1) Validate 0 <= c < n */
	43	if (mpi_cmp_ui(c, 0) < 0 \|\| mpi_cmp(c, key->n) >= 0)
	44	return -EINVAL;
	45
	46	/* (2) m = c^d mod n */
	47	return mpi_powm(m, c, key->d, key->n);
	48	}
	49
5a7de973	50	static inline struct rsa_mpi_key rsa_get_key(struct crypto_akcipher tfm)
cfc2bb32 TS	51	{
	52	return akcipher_tfm_ctx(tfm);
	53	}
	54
	55	static int rsa_enc(struct akcipher_request *req)
	56	{
	57	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
5a7de973	58	const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
cfc2bb32 TS	59	MPI m, c = mpi_alloc(0);
	60	int ret = 0;
	61	int sign;
	62
	63	if (!c)
	64	return -ENOMEM;
	65
	66	if (unlikely(!pkey->n \|\| !pkey->e)) {
	67	ret = -EINVAL;
	68	goto err_free_c;
	69	}
	70
22287b0b TS	71	ret = -ENOMEM;
	72	m = mpi_read_raw_from_sgl(req->src, req->src_len);
	73	if (!m)
cfc2bb32	74	goto err_free_c;
cfc2bb32 TS	75
	76	ret = _rsa_enc(pkey, c, m);
	77	if (ret)
	78	goto err_free_m;
	79
9b45b7bb	80	ret = mpi_write_to_sgl(c, req->dst, req->dst_len, &sign);
cfc2bb32 TS	81	if (ret)
	82	goto err_free_m;
	83
22287b0b	84	if (sign < 0)
cfc2bb32	85	ret = -EBADMSG;
cfc2bb32 TS	86
	87	err_free_m:
	88	mpi_free(m);
	89	err_free_c:
	90	mpi_free(c);
	91	return ret;
	92	}
	93
	94	static int rsa_dec(struct akcipher_request *req)
	95	{
	96	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
5a7de973	97	const struct rsa_mpi_key *pkey = rsa_get_key(tfm);
cfc2bb32 TS	98	MPI c, m = mpi_alloc(0);
	99	int ret = 0;
	100	int sign;
	101
	102	if (!m)
	103	return -ENOMEM;
	104
	105	if (unlikely(!pkey->n \|\| !pkey->d)) {
	106	ret = -EINVAL;
	107	goto err_free_m;
	108	}
	109
22287b0b TS	110	ret = -ENOMEM;
	111	c = mpi_read_raw_from_sgl(req->src, req->src_len);
	112	if (!c)
cfc2bb32	113	goto err_free_m;
cfc2bb32 TS	114
	115	ret = _rsa_dec(pkey, m, c);
	116	if (ret)
	117	goto err_free_c;
	118
9b45b7bb	119	ret = mpi_write_to_sgl(m, req->dst, req->dst_len, &sign);
cfc2bb32 TS	120	if (ret)
	121	goto err_free_c;
	122
22287b0b	123	if (sign < 0)
cfc2bb32	124	ret = -EBADMSG;
cfc2bb32 TS	125	err_free_c:
	126	mpi_free(c);
	127	err_free_m:
	128	mpi_free(m);
	129	return ret;
	130	}
	131
5a7de973 TA	132	static void rsa_free_mpi_key(struct rsa_mpi_key *key)
	133	{
	134	mpi_free(key->d);
	135	mpi_free(key->e);
	136	mpi_free(key->n);
	137	key->d = NULL;
	138	key->e = NULL;
	139	key->n = NULL;
	140	}
	141
6e8ec66c TS	142	static int rsa_check_key_length(unsigned int len)
	143	{
	144	switch (len) {
	145	case 512:
	146	case 1024:
	147	case 1536:
1ce1bacc SM	148	if (fips_enabled)
	149	return -EINVAL;
	150	fallthrough;
6e8ec66c TS	151	case 2048:
	152	case 3072:
	153	case 4096:
	154	return 0;
	155	}
	156
	157	return -EINVAL;
	158	}
	159
22287b0b TS	160	static int rsa_set_pub_key(struct crypto_akcipher tfm, const void key,
22287b0b TS	161	unsigned int keylen)
cfc2bb32	162	{
5a7de973 TA	163	struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
5a7de973 TA	164	struct rsa_key raw_key = {0};
6e8ec66c	165	int ret;
cfc2bb32	166
5a7de973 TA	167	/* Free the old MPI key if any */
	168	rsa_free_mpi_key(mpi_key);
	169
	170	ret = rsa_parse_pub_key(&raw_key, key, keylen);
6e8ec66c TS	171	if (ret)
	172	return ret;
	173
5a7de973 TA	174	mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
	175	if (!mpi_key->e)
	176	goto err;
	177
	178	mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
	179	if (!mpi_key->n)
	180	goto err;
	181
	182	if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
	183	rsa_free_mpi_key(mpi_key);
	184	return -EINVAL;
6e8ec66c	185	}
5a7de973 TA	186
	187	return 0;
	188
	189	err:
	190	rsa_free_mpi_key(mpi_key);
	191	return -ENOMEM;
cfc2bb32 TS	192	}
cfc2bb32 TS	193
22287b0b TS	194	static int rsa_set_priv_key(struct crypto_akcipher tfm, const void key,
	195	unsigned int keylen)
	196	{
5a7de973 TA	197	struct rsa_mpi_key *mpi_key = akcipher_tfm_ctx(tfm);
5a7de973 TA	198	struct rsa_key raw_key = {0};
22287b0b TS	199	int ret;
22287b0b TS	200
5a7de973 TA	201	/* Free the old MPI key if any */
	202	rsa_free_mpi_key(mpi_key);
	203
	204	ret = rsa_parse_priv_key(&raw_key, key, keylen);
22287b0b TS	205	if (ret)
	206	return ret;
	207
5a7de973 TA	208	mpi_key->d = mpi_read_raw_data(raw_key.d, raw_key.d_sz);
	209	if (!mpi_key->d)
	210	goto err;
	211
	212	mpi_key->e = mpi_read_raw_data(raw_key.e, raw_key.e_sz);
	213	if (!mpi_key->e)
	214	goto err;
	215
	216	mpi_key->n = mpi_read_raw_data(raw_key.n, raw_key.n_sz);
	217	if (!mpi_key->n)
	218	goto err;
	219
	220	if (rsa_check_key_length(mpi_get_size(mpi_key->n) << 3)) {
	221	rsa_free_mpi_key(mpi_key);
	222	return -EINVAL;
22287b0b	223	}
5a7de973 TA	224
	225	return 0;
	226
	227	err:
	228	rsa_free_mpi_key(mpi_key);
	229	return -ENOMEM;
22287b0b TS	230	}
22287b0b TS	231
1c23b466	232	static unsigned int rsa_max_size(struct crypto_akcipher *tfm)
22287b0b	233	{
5a7de973	234	struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
22287b0b	235
1c23b466	236	return mpi_get_size(pkey->n);
22287b0b TS	237	}
22287b0b TS	238
cfc2bb32 TS	239	static void rsa_exit_tfm(struct crypto_akcipher *tfm)
cfc2bb32 TS	240	{
5a7de973	241	struct rsa_mpi_key *pkey = akcipher_tfm_ctx(tfm);
cfc2bb32	242
5a7de973	243	rsa_free_mpi_key(pkey);
cfc2bb32 TS	244	}
	245
	246	static struct akcipher_alg rsa = {
	247	.encrypt = rsa_enc,
	248	.decrypt = rsa_dec,
22287b0b TS	249	.set_priv_key = rsa_set_priv_key,
	250	.set_pub_key = rsa_set_pub_key,
	251	.max_size = rsa_max_size,
cfc2bb32 TS	252	.exit = rsa_exit_tfm,
	253	.base = {
	254	.cra_name = "rsa",
	255	.cra_driver_name = "rsa-generic",
	256	.cra_priority = 100,
	257	.cra_module = THIS_MODULE,
5a7de973	258	.cra_ctxsize = sizeof(struct rsa_mpi_key),
cfc2bb32 TS	259	},
	260	};
	261
	262	static int rsa_init(void)
	263	{
3d5b1ecd AZ	264	int err;
	265
	266	err = crypto_register_akcipher(&rsa);
	267	if (err)
	268	return err;
	269
	270	err = crypto_register_template(&rsa_pkcs1pad_tmpl);
	271	if (err) {
	272	crypto_unregister_akcipher(&rsa);
	273	return err;
	274	}
	275
	276	return 0;
cfc2bb32 TS	277	}
	278
	279	static void rsa_exit(void)
	280	{
3d5b1ecd	281	crypto_unregister_template(&rsa_pkcs1pad_tmpl);
cfc2bb32 TS	282	crypto_unregister_akcipher(&rsa);
	283	}
	284
c4741b23	285	subsys_initcall(rsa_init);
cfc2bb32 TS	286	module_exit(rsa_exit);
	287	MODULE_ALIAS_CRYPTO("rsa");
	288	MODULE_LICENSE("GPL");
	289	MODULE_DESCRIPTION("RSA generic algorithm");