linux/kernel/module_signing.c
Thiago Jung Bauermann c8424e776b MODSIGN: Export module signature definitions
IMA will use the module_signature format for append signatures, so export
the relevant definitions and factor out the code which verifies that the
appended signature trailer is valid.

Also, create a CONFIG_MODULE_SIG_FORMAT option so that IMA can select it
and be able to use mod_check_sig() without having to depend on either
CONFIG_MODULE_SIG or CONFIG_MODULES.

s390 duplicated the definition of struct module_signature so now they can
use the new <linux/module_signature.h> header instead.

Signed-off-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Acked-by: Jessica Yu <jeyu@kernel.org>
Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2019-08-05 18:39:56 -04:00

46 lines
1.1 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/* Module signature checker
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/module_signature.h>
#include <linux/string.h>
#include <linux/verification.h>
#include <crypto/public_key.h>
#include "module-internal.h"
/*
* Verify the signature on a module.
*/
int mod_verify_sig(const void *mod, struct load_info *info)
{
struct module_signature ms;
size_t sig_len, modlen = info->len;
int ret;
pr_devel("==>%s(,%zu)\n", __func__, modlen);
if (modlen <= sizeof(ms))
return -EBADMSG;
memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms));
ret = mod_check_sig(&ms, modlen, info->name);
if (ret)
return ret;
sig_len = be32_to_cpu(ms.sig_len);
modlen -= sig_len + sizeof(ms);
info->len = modlen;
return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len,
VERIFY_USE_SECONDARY_KEYRING,
VERIFYING_MODULE_SIGNATURE,
NULL, NULL);
}