crypto/rsa.c - linux - Git at Google

 // 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;
 	MPI p;
 	MPI q;
 	MPI dp;
 	MPI dq;
 	MPI qinv;
 };

 /*
  * 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_1 = c^dP mod p;
  * m_2 = c^dQ mod q;
  * h = (m_1 - m_2) * qInv mod p;
  * m = m_2 + q * h;
  */
 static int _rsa_dec_crt(const struct rsa_mpi_key *key, MPI m_or_m1_or_h, MPI c)
 {
 	MPI m2, m12_or_qh;
 	int ret = -ENOMEM;

 	/* (1) Validate 0 <= c < n */
 	if (mpi_cmp_ui(c, 0) < 0 || mpi_cmp(c, key->n) >= 0)
 		return -EINVAL;

 	m2 = mpi_alloc(0);
 	m12_or_qh = mpi_alloc(0);
 	if (!m2 || !m12_or_qh)
 		goto err_free_mpi;

 	/* (2i) m_1 = c^dP mod p */
 	ret = mpi_powm(m_or_m1_or_h, c, key->dp, key->p);
 	if (ret)
 		goto err_free_mpi;

 	/* (2i) m_2 = c^dQ mod q */
 	ret = mpi_powm(m2, c, key->dq, key->q);
 	if (ret)
 		goto err_free_mpi;

 	/* (2iii) h = (m_1 - m_2) * qInv mod p */
 	mpi_sub(m12_or_qh, m_or_m1_or_h, m2);
 	mpi_mulm(m_or_m1_or_h, m12_or_qh, key->qinv, key->p);

 	/* (2iv) m = m_2 + q * h */
 	mpi_mul(m12_or_qh, key->q, m_or_m1_or_h);
 	mpi_addm(m_or_m1_or_h, m2, m12_or_qh, key->n);

 	ret = 0;

 err_free_mpi:
 	mpi_free(m12_or_qh);
 	mpi_free(m2);
 	return ret;
 }

 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_crt(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);
 	mpi_free(key->p);
 	mpi_free(key->q);
 	mpi_free(key->dp);
 	mpi_free(key->dq);
 	mpi_free(key->qinv);
 	key->d = NULL;
 	key->e = NULL;
 	key->n = NULL;
 	key->p = NULL;
 	key->q = NULL;
 	key->dp = NULL;
 	key->dq = NULL;
 	key->qinv = 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_check_exponent_fips(MPI e)
 {
 	MPI e_max = NULL;

 	/* check if odd */
 	if (!mpi_test_bit(e, 0)) {
 		return -EINVAL;
 	}

 	/* check if 2^16 < e < 2^256. */
 	if (mpi_cmp_ui(e, 65536) <= 0) {
 		return -EINVAL;
 	}

 	e_max = mpi_alloc(0);
 	if (!e_max)
 		return -ENOMEM;
 	mpi_set_bit(e_max, 256);

 	if (mpi_cmp(e, e_max) >= 0) {
 		mpi_free(e_max);
 		return -EINVAL;
 	}

 	mpi_free(e_max);
 	return 0;
 }

 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;
 	}

 	if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) {
 		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;

 	mpi_key->p = mpi_read_raw_data(raw_key.p, raw_key.p_sz);
 	if (!mpi_key->p)
 		goto err;

 	mpi_key->q = mpi_read_raw_data(raw_key.q, raw_key.q_sz);
 	if (!mpi_key->q)
 		goto err;

 	mpi_key->dp = mpi_read_raw_data(raw_key.dp, raw_key.dp_sz);
 	if (!mpi_key->dp)
 		goto err;

 	mpi_key->dq = mpi_read_raw_data(raw_key.dq, raw_key.dq_sz);
 	if (!mpi_key->dq)
 		goto err;

 	mpi_key->qinv = mpi_read_raw_data(raw_key.qinv, raw_key.qinv_sz);
 	if (!mpi_key->qinv)
 		goto err;

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

 	if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) {
 		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 __init 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 __exit 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");
	// 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;
	MPI p;
	MPI q;
	MPI dp;
	MPI dq;
	MPI qinv;
	};

	/*
	* 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_1 = c^dP mod p;
	* m_2 = c^dQ mod q;
	* h = (m_1 - m_2) * qInv mod p;
	* m = m_2 + q * h;
	*/
	static int _rsa_dec_crt(const struct rsa_mpi_key *key, MPI m_or_m1_or_h, MPI c)
	{
	MPI m2, m12_or_qh;
	int ret = -ENOMEM;

	/* (1) Validate 0 <= c < n */
	if (mpi_cmp_ui(c, 0) < 0 \|\| mpi_cmp(c, key->n) >= 0)
	return -EINVAL;

	m2 = mpi_alloc(0);
	m12_or_qh = mpi_alloc(0);
	if (!m2 \|\| !m12_or_qh)
	goto err_free_mpi;

	/* (2i) m_1 = c^dP mod p */
	ret = mpi_powm(m_or_m1_or_h, c, key->dp, key->p);
	if (ret)
	goto err_free_mpi;

	/* (2i) m_2 = c^dQ mod q */
	ret = mpi_powm(m2, c, key->dq, key->q);
	if (ret)
	goto err_free_mpi;

	/* (2iii) h = (m_1 - m_2) * qInv mod p */
	mpi_sub(m12_or_qh, m_or_m1_or_h, m2);
	mpi_mulm(m_or_m1_or_h, m12_or_qh, key->qinv, key->p);

	/* (2iv) m = m_2 + q * h */
	mpi_mul(m12_or_qh, key->q, m_or_m1_or_h);
	mpi_addm(m_or_m1_or_h, m2, m12_or_qh, key->n);

	ret = 0;

	err_free_mpi:
	mpi_free(m12_or_qh);
	mpi_free(m2);
	return ret;
	}

	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_crt(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);
	mpi_free(key->p);
	mpi_free(key->q);
	mpi_free(key->dp);
	mpi_free(key->dq);
	mpi_free(key->qinv);
	key->d = NULL;
	key->e = NULL;
	key->n = NULL;
	key->p = NULL;
	key->q = NULL;
	key->dp = NULL;
	key->dq = NULL;
	key->qinv = 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_check_exponent_fips(MPI e)
	{
	MPI e_max = NULL;

	/* check if odd */
	if (!mpi_test_bit(e, 0)) {
	return -EINVAL;
	}

	/* check if 2^16 < e < 2^256. */
	if (mpi_cmp_ui(e, 65536) <= 0) {
	return -EINVAL;
	}

	e_max = mpi_alloc(0);
	if (!e_max)
	return -ENOMEM;
	mpi_set_bit(e_max, 256);

	if (mpi_cmp(e, e_max) >= 0) {
	mpi_free(e_max);
	return -EINVAL;
	}

	mpi_free(e_max);
	return 0;
	}

	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;
	}

	if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) {
	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;

	mpi_key->p = mpi_read_raw_data(raw_key.p, raw_key.p_sz);
	if (!mpi_key->p)
	goto err;

	mpi_key->q = mpi_read_raw_data(raw_key.q, raw_key.q_sz);
	if (!mpi_key->q)
	goto err;

	mpi_key->dp = mpi_read_raw_data(raw_key.dp, raw_key.dp_sz);
	if (!mpi_key->dp)
	goto err;

	mpi_key->dq = mpi_read_raw_data(raw_key.dq, raw_key.dq_sz);
	if (!mpi_key->dq)
	goto err;

	mpi_key->qinv = mpi_read_raw_data(raw_key.qinv, raw_key.qinv_sz);
	if (!mpi_key->qinv)
	goto err;

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

	if (fips_enabled && rsa_check_exponent_fips(mpi_key->e)) {
	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 __init 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 __exit 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");