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/* In-software asymmetric public-key crypto subtype
*
* See Documentation/crypto/asymmetric-keys.txt
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#define pr_fmt(fmt) "PKEY: "fmt
#include <linux/module.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <keys/asymmetric-subtype.h>
#include "public_key.h"
MODULE_LICENSE("GPL");
const char *const pkey_algo_name[PKEY_ALGO__LAST] = {
[PKEY_ALGO_DSA] = "DSA",
[PKEY_ALGO_RSA] = "RSA",
};
EXPORT_SYMBOL_GPL(pkey_algo_name);
const struct public_key_algorithm *pkey_algo[PKEY_ALGO__LAST] = {
#if defined(CONFIG_PUBLIC_KEY_ALGO_RSA) || \
defined(CONFIG_PUBLIC_KEY_ALGO_RSA_MODULE)
[PKEY_ALGO_RSA] = &RSA_public_key_algorithm,
#endif
};
EXPORT_SYMBOL_GPL(pkey_algo);
const char *const pkey_id_type_name[PKEY_ID_TYPE__LAST] = {
[PKEY_ID_PGP] = "PGP",
[PKEY_ID_X509] = "X509",
};
EXPORT_SYMBOL_GPL(pkey_id_type_name);
/*
* Provide a part of a description of the key for /proc/keys.
*/
static void public_key_describe(const struct key *asymmetric_key,
struct seq_file *m)
{
struct public_key *key = asymmetric_key->payload.data;
if (key)
seq_printf(m, "%s.%s",
pkey_id_type_name[key->id_type], key->algo->name);
}
/*
* Destroy a public key algorithm key.
*/
void public_key_destroy(void *payload)
{
struct public_key *key = payload;
int i;
if (key) {
for (i = 0; i < ARRAY_SIZE(key->mpi); i++)
mpi_free(key->mpi[i]);
kfree(key);
}
}
EXPORT_SYMBOL_GPL(public_key_destroy);
/*
* Verify a signature using a public key.
*/
int public_key_verify_signature(const struct public_key *pk,
const struct public_key_signature *sig)
{
const struct public_key_algorithm *algo;
BUG_ON(!pk);
BUG_ON(!pk->mpi[0]);
BUG_ON(!pk->mpi[1]);
BUG_ON(!sig);
BUG_ON(!sig->digest);
BUG_ON(!sig->mpi[0]);
algo = pk->algo;
if (!algo) {
if (pk->pkey_algo >= PKEY_ALGO__LAST)
return -ENOPKG;
algo = pkey_algo[pk->pkey_algo];
if (!algo)
return -ENOPKG;
}
if (!algo->verify_signature)
return -ENOTSUPP;
if (sig->nr_mpi != algo->n_sig_mpi) {
pr_debug("Signature has %u MPI not %u\n",
sig->nr_mpi, algo->n_sig_mpi);
return -EINVAL;
}
return algo->verify_signature(pk, sig);
}
EXPORT_SYMBOL_GPL(public_key_verify_signature);
static int public_key_verify_signature_2(const struct key *key,
const struct public_key_signature *sig)
{
const struct public_key *pk = key->payload.data;
return public_key_verify_signature(pk, sig);
}
/*
* Public key algorithm asymmetric key subtype
*/
struct asymmetric_key_subtype public_key_subtype = {
.owner = THIS_MODULE,
.name = "public_key",
.name_len = sizeof("public_key") - 1,
.describe = public_key_describe,
.destroy = public_key_destroy,
.verify_signature = public_key_verify_signature_2,
};
EXPORT_SYMBOL_GPL(public_key_subtype);
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