// SPDX-License-Identifier: GPL-2.0-or-later
/* Signature verification with an asymmetric key
*
* See Documentation/crypto/asymmetric-keys.rst
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*/
#define pr_fmt(fmt) "SIG: "fmt
#include <keys/asymmetric-subtype.h>
#include <linux/export.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/keyctl.h>
#include <crypto/public_key.h>
#include <keys/user-type.h>
#include "asymmetric_keys.h"
/*
* Destroy a public key signature.
*/
void public_key_signature_free(struct public_key_signature *sig)
{
int i;
if (sig) {
for (i = 0; i < ARRAY_SIZE(sig->auth_ids); i++)
kfree(sig->auth_ids[i]);
kfree(sig->s);
kfree(sig->digest);
kfree(sig);
}
}
EXPORT_SYMBOL_GPL(public_key_signature_free);
/**
* query_asymmetric_key - Get information about an asymmetric key.
* @params: Various parameters.
* @info: Where to put the information.
*/
int query_asymmetric_key(const struct kernel_pkey_params *params,
struct kernel_pkey_query *info)
{
const struct asymmetric_key_subtype *subtype;
struct key *key = params->key;
int ret;
pr_devel("==>%s()\n", __func__);
if (key->type != &key_type_asymmetric)
return -EINVAL;
subtype = asymmetric_key_subtype(key);
if (!subtype ||
!key->payload.data[0])
return -EINVAL;
if (!subtype->query)
return -ENOTSUPP;
ret = subtype->query(params, info);
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
}
EXPORT_SYMBOL_GPL(query_asymmetric_key);
/**
* encrypt_blob - Encrypt data using an asymmetric key
* @params: Various parameters
* @data: Data blob to be encrypted, length params->data_len
* @enc: Encrypted data buffer, length params->enc_len
*
* Encrypt the specified data blob using the private key specified by
* params->key. The encrypted data is wrapped in an encoding if
* params->encoding is specified (eg. "pkcs1").
*
* Returns the length of the data placed in the encrypted data buffer or an
* error.
*/
int encrypt_blob(struct kernel_pkey_params *params,
const void *data, void *enc)
{
params->op = kernel_pkey_encrypt;
return asymmetric_key_eds_op(params, data, enc);
}
EXPORT_SYMBOL_GPL(encrypt_blob);
/**
* decrypt_blob - Decrypt data using an asymmetric key
* @params: Various parameters
* @enc: Encrypted data to be decrypted, length params->enc_len
* @data: Decrypted data buffer, length params->data_len
*
* Decrypt the specified data blob using the private key specified by
* params->key. The decrypted data is wrapped in an encoding if
* params->encoding is specified (eg. "pkcs1").
*
* Returns the length of the data placed in the decrypted data buffer or an
* error.
*/
int decrypt_blob(struct kernel_pkey_params *params,
const void *enc, void *data)
{
params->op = kernel_pkey_decrypt;
return asymmetric_key_eds_op(params, enc, data);
}
EXPORT_SYMBOL_GPL(decrypt_blob);
/**
* create_signature - Sign some data using an asymmetric key
* @params: Various parameters
* @data: Data blob to be signed, length params->data_len
* @enc: Signature buffer, length params->enc_len
*
* Sign the specified data blob using the private key specified by params->key.
* The signature is wrapped in an encoding if params->encoding is specified
* (eg. "pkcs1"). If the encoding needs to know the digest type, this can be
* passed through params->hash_algo (eg. "sha1").
*
* Returns the length of the data placed in the signature buffer or an error.
*/
int create_signature(struct kernel_pkey_params *params,
const void *data, void *enc)
{
params->op = kernel_pkey_sign;
return asymmetric_key_eds_op(params, data, enc);
}
EXPORT_SYMBOL_GPL(create_signature);
/**
* verify_signature - Initiate the use of an asymmetric key to verify a signature
* @key: The asymmetric key to verify against
* @sig: The signature to check
*
* Returns 0 if successful or else an error.
*/
int verify_signature(const struct key *key,
const struct public_key_signature *sig)
{
const struct asymmetric_key_subtype *subtype;
int ret;
pr_devel("==>%s()\n", __func__);
if (key->type != &key_type_asymmetric)
return -EINVAL;
subtype = asymmetric_key_subtype(key);
if (!subtype ||
!key->payload.data[0])
return -EINVAL;
if (!subtype->verify_signature)
return -ENOTSUPP;
ret = subtype->verify_signature(key, sig);
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
}
EXPORT_SYMBOL_GPL(verify_signature);