// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * RSA key extract helper
 *
 * Copyright (c) 2015, Intel Corporation
 * Authors: Tadeusz Struk <tadeusz.struk@intel.com>
 */
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/fips.h>
#ifdef CONFIG_PGP_LIBRARY
#include <linux/mpi.h>
#endif
#include <crypto/internal/rsa.h>
#include "rsapubkey.asn1.h"
#include "rsaprivkey.asn1.h"

int rsa_get_n(void *context, size_t hdrlen, unsigned char tag,
	      const void *value, size_t vlen)
{
	struct rsa_key *key = context;
	const u8 *ptr = value;
	size_t n_sz = vlen;

	/* invalid key provided */
	if (!value || !vlen)
		return -EINVAL;

	if (fips_enabled) {
		while (n_sz && !*ptr) {
			ptr++;
			n_sz--;
		}

		/* In FIPS mode only allow key size 2K and higher */
		if (n_sz < 256) {
			pr_err("RSA: key size not allowed in FIPS mode\n");
			return -EINVAL;
		}
	}

	key->n = value;
	key->n_sz = vlen;

	return 0;
}

int rsa_get_e(void *context, size_t hdrlen, unsigned char tag,
	      const void *value, size_t vlen)
{
	struct rsa_key *key = context;

	/* invalid key provided */
	if (!value || !key->n_sz || !vlen || vlen > key->n_sz)
		return -EINVAL;

	key->e = value;
	key->e_sz = vlen;

	return 0;
}

int rsa_get_d(void *context, size_t hdrlen, unsigned char tag,
	      const void *value, size_t vlen)
{
	struct rsa_key *key = context;

	/* invalid key provided */
	if (!value || !key->n_sz || !vlen || vlen > key->n_sz)
		return -EINVAL;

	key->d = value;
	key->d_sz = vlen;

	return 0;
}

int rsa_get_p(void *context, size_t hdrlen, unsigned char tag,
	      const void *value, size_t vlen)
{
	struct rsa_key *key = context;

	/* invalid key provided */
	if (!value || !vlen || vlen > key->n_sz)
		return -EINVAL;

	key->p = value;
	key->p_sz = vlen;

	return 0;
}

int rsa_get_q(void *context, size_t hdrlen, unsigned char tag,
	      const void *value, size_t vlen)
{
	struct rsa_key *key = context;

	/* invalid key provided */
	if (!value || !vlen || vlen > key->n_sz)
		return -EINVAL;

	key->q = value;
	key->q_sz = vlen;

	return 0;
}

int rsa_get_dp(void *context, size_t hdrlen, unsigned char tag,
	       const void *value, size_t vlen)
{
	struct rsa_key *key = context;

	/* invalid key provided */
	if (!value || !vlen || vlen > key->n_sz)
		return -EINVAL;

	key->dp = value;
	key->dp_sz = vlen;

	return 0;
}

int rsa_get_dq(void *context, size_t hdrlen, unsigned char tag,
	       const void *value, size_t vlen)
{
	struct rsa_key *key = context;

	/* invalid key provided */
	if (!value || !vlen || vlen > key->n_sz)
		return -EINVAL;

	key->dq = value;
	key->dq_sz = vlen;

	return 0;
}

int rsa_get_qinv(void *context, size_t hdrlen, unsigned char tag,
		 const void *value, size_t vlen)
{
	struct rsa_key *key = context;

	/* invalid key provided */
	if (!value || !vlen || vlen > key->n_sz)
		return -EINVAL;

	key->qinv = value;
	key->qinv_sz = vlen;

	return 0;
}

#ifdef CONFIG_PGP_LIBRARY
typedef int (*rsa_get_func)(void *, size_t, unsigned char,
			    const void *, size_t);

static int rsa_parse_key_raw(struct rsa_key *rsa_key,
			     const void *key, unsigned int key_len,
			     rsa_get_func *func, int n_func)
{
	unsigned int nbytes, len = key_len;
	const void *key_ptr = key;
	int ret, i;

	for (i = 0; i < n_func; i++) {
		ret = mpi_key_length(key_ptr, len, NULL, &nbytes);
		if (ret < 0)
			return ret;

		ret = func[i](rsa_key, 0, 0, key_ptr + 2, nbytes);
		if (ret < 0)
			return ret;

		key_ptr += nbytes + 2;
	}

	return (key_ptr == key + key_len) ? 0 : -EINVAL;
}
#endif

/**
 * rsa_parse_pub_key() - decodes the BER encoded buffer and stores in the
 *                       provided struct rsa_key, pointers to the raw key as is,
 *                       so that the caller can copy it or MPI parse it, etc.
 *
 * @rsa_key:	struct rsa_key key representation
 * @key:	key in BER format
 * @key_len:	length of key
 *
 * Return:	0 on success or error code in case of error
 */
int rsa_parse_pub_key(struct rsa_key *rsa_key, const void *key,
		      unsigned int key_len)
{
	return asn1_ber_decoder(&rsapubkey_decoder, rsa_key, key, key_len);
}
EXPORT_SYMBOL_GPL(rsa_parse_pub_key);

#ifdef CONFIG_PGP_LIBRARY
/**
 * rsa_parse_pub_key_raw() - parse the RAW key and store in the provided struct
 *                           rsa_key, pointers to the raw key as is, so that
 *                           the caller can copy it or MPI parse it, etc.
 *
 * @rsa_key:	struct rsa_key key representation
 * @key:	key in RAW format
 * @key_len:	length of key
 *
 * Return:	0 on success or error code in case of error
 */
int rsa_parse_pub_key_raw(struct rsa_key *rsa_key, const void *key,
			  unsigned int key_len)
{
	rsa_get_func pub_func[] = {rsa_get_n, rsa_get_e};

	return rsa_parse_key_raw(rsa_key, key, key_len,
				 pub_func, ARRAY_SIZE(pub_func));
}
EXPORT_SYMBOL_GPL(rsa_parse_pub_key_raw);
#endif
/**
 * rsa_parse_priv_key() - decodes the BER encoded buffer and stores in the
 *                        provided struct rsa_key, pointers to the raw key
 *                        as is, so that the caller can copy it or MPI parse it,
 *                        etc.
 *
 * @rsa_key:	struct rsa_key key representation
 * @key:	key in BER format
 * @key_len:	length of key
 *
 * Return:	0 on success or error code in case of error
 */
int rsa_parse_priv_key(struct rsa_key *rsa_key, const void *key,
		       unsigned int key_len)
{
	return asn1_ber_decoder(&rsaprivkey_decoder, rsa_key, key, key_len);
}
EXPORT_SYMBOL_GPL(rsa_parse_priv_key);

#ifdef CONFIG_PGP_LIBRARY
/**
 * rsa_parse_priv_key_raw() - parse the RAW key and store in the provided struct
 *                            rsa_key, pointers to the raw key as is, so that
 *                            the caller can copy it or MPI parse it, etc.
 *
 * @rsa_key:	struct rsa_key key representation
 * @key:	key in RAW format
 * @key_len:	length of key
 *
 * Return:	0 on success or error code in case of error
 */
int rsa_parse_priv_key_raw(struct rsa_key *rsa_key, const void *key,
			   unsigned int key_len)
{
	rsa_get_func priv_func[] = {rsa_get_n, rsa_get_e, rsa_get_d};

	return rsa_parse_key_raw(rsa_key, key, key_len,
				 priv_func, ARRAY_SIZE(priv_func));
}
EXPORT_SYMBOL_GPL(rsa_parse_priv_key_raw);
#endif