linux/lib/digsig.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2011 Nokia Corporation
 * Copyright (C) 2011 Intel Corporation
 *
 * Author:
 * Dmitry Kasatkin <[email protected]>
 *                 <[email protected]>
 *
 * File: sign.c
 *	implements signature (RSA) verification
 *	pkcs decoding is based on LibTomCrypt code
 */

#define pr_fmt(fmt) …

#include <linux/err.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/key.h>
#include <linux/crypto.h>
#include <crypto/hash.h>
#include <crypto/sha1.h>
#include <keys/user-type.h>
#include <linux/mpi.h>
#include <linux/digsig.h>

static struct crypto_shash *shash;

static const char *pkcs_1_v1_5_decode_emsa(const unsigned char *msg,
						unsigned long  msglen,
						unsigned long  modulus_bitlen,
						unsigned long *outlen)
{ … }

/*
 * RSA Signature verification with public key
 */
static int digsig_verify_rsa(struct key *key,
		    const char *sig, int siglen,
		       const char *h, int hlen)
{ … }

/**
 * digsig_verify() - digital signature verification with public key
 * @keyring:	keyring to search key in
 * @sig:	digital signature
 * @siglen:	length of the signature
 * @data:	data
 * @datalen:	length of the data
 *
 * Returns 0 on success, -EINVAL otherwise
 *
 * Verifies data integrity against digital signature.
 * Currently only RSA is supported.
 * Normally hash of the content is used as a data for this function.
 *
 */
int digsig_verify(struct key *keyring, const char *sig, int siglen,
						const char *data, int datalen)
{ … }
EXPORT_SYMBOL_GPL(…);

static int __init digsig_init(void)
{ … }

static void __exit digsig_cleanup(void)
{ … }

module_init(…) …;
module_exit(digsig_cleanup);

MODULE_LICENSE(…) …;