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/*
* libkmod - module signature display
*
* Copyright (C) 2013 Michal Marek, SUSE
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <endian.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "libkmod-private.h"
/* These types and tables were copied from the 3.7 kernel sources.
* As this is just description of the signature format, it should not be
* considered derived work (so libkmod can use the LGPL license).
*/
enum pkey_algo {
PKEY_ALGO_DSA,
PKEY_ALGO_RSA,
PKEY_ALGO__LAST
};
static const char *const pkey_algo[PKEY_ALGO__LAST] = {
[PKEY_ALGO_DSA] = "DSA",
[PKEY_ALGO_RSA] = "RSA",
};
enum pkey_hash_algo {
PKEY_HASH_MD4,
PKEY_HASH_MD5,
PKEY_HASH_SHA1,
PKEY_HASH_RIPE_MD_160,
PKEY_HASH_SHA256,
PKEY_HASH_SHA384,
PKEY_HASH_SHA512,
PKEY_HASH_SHA224,
PKEY_HASH__LAST
};
const char *const pkey_hash_algo[PKEY_HASH__LAST] = {
[PKEY_HASH_MD4] = "md4",
[PKEY_HASH_MD5] = "md5",
[PKEY_HASH_SHA1] = "sha1",
[PKEY_HASH_RIPE_MD_160] = "rmd160",
[PKEY_HASH_SHA256] = "sha256",
[PKEY_HASH_SHA384] = "sha384",
[PKEY_HASH_SHA512] = "sha512",
[PKEY_HASH_SHA224] = "sha224",
};
enum pkey_id_type {
PKEY_ID_PGP, /* OpenPGP generated key ID */
PKEY_ID_X509, /* X.509 arbitrary subjectKeyIdentifier */
PKEY_ID_TYPE__LAST
};
const char *const pkey_id_type[PKEY_ID_TYPE__LAST] = {
[PKEY_ID_PGP] = "PGP",
[PKEY_ID_X509] = "X509",
};
/*
* Module signature information block.
*
* The constituents of the signature section are, in order:
*
* - Signer's name
* - Key identifier
* - Signature data
* - Information block
*/
struct module_signature {
uint8_t algo; /* Public-key crypto algorithm [enum pkey_algo] */
uint8_t hash; /* Digest algorithm [enum pkey_hash_algo] */
uint8_t id_type; /* Key identifier type [enum pkey_id_type] */
uint8_t signer_len; /* Length of signer's name */
uint8_t key_id_len; /* Length of key identifier */
uint8_t __pad[3];
uint32_t sig_len; /* Length of signature data (big endian) */
};
#define SIG_MAGIC "~Module signature appended~\n"
bool kmod_module_signature_info(const struct kmod_file *file, struct kmod_signature_info *sig_info)
{
const char *mem;
off_t size;
const struct module_signature *modsig;
size_t sig_len;
size = kmod_file_get_size(file);
mem = kmod_file_get_contents(file);
if (size < (off_t)strlen(SIG_MAGIC))
return false;
size -= strlen(SIG_MAGIC);
if (memcmp(SIG_MAGIC, mem + size, strlen(SIG_MAGIC)) != 0)
return false;
if (size < (off_t)sizeof(struct module_signature))
return false;
size -= sizeof(struct module_signature);
modsig = (struct module_signature *)(mem + size);
if (modsig->algo >= PKEY_ALGO__LAST ||
modsig->hash >= PKEY_HASH__LAST ||
modsig->id_type >= PKEY_ID_TYPE__LAST)
return false;
sig_len = be32toh(modsig->sig_len);
if (size < (off_t)(modsig->signer_len + modsig->key_id_len + sig_len))
return false;
size -= modsig->key_id_len + sig_len;
sig_info->key_id = mem + size;
sig_info->key_id_len = modsig->key_id_len;
size -= modsig->signer_len;
sig_info->signer = mem + size;
sig_info->signer_len = modsig->signer_len;
sig_info->algo = pkey_algo[modsig->algo];
sig_info->hash_algo = pkey_hash_algo[modsig->hash];
sig_info->id_type = pkey_id_type[modsig->id_type];
return true;
}
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