linux/kernel/module_signature.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

47 lines
1.1 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* Module signature checker
*
* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*/
#include <linux/errno.h>
#include <linux/printk.h>
#include <linux/module_signature.h>
#include <asm/byteorder.h>
/**
* mod_check_sig - check that the given signature is sane
*
* @ms: Signature to check.
* @file_len: Size of the file to which @ms is appended.
* @name: What is being checked. Used for error messages.
*/
int mod_check_sig(const struct module_signature *ms, size_t file_len,
const char *name)
{
if (be32_to_cpu(ms->sig_len) >= file_len - sizeof(*ms))
return -EBADMSG;
if (ms->id_type != PKEY_ID_PKCS7) {
pr_err("%s: Module is not signed with expected PKCS#7 message\n",
name);
return -ENOPKG;
}
if (ms->algo != 0 ||
ms->hash != 0 ||
ms->signer_len != 0 ||
ms->key_id_len != 0 ||
ms->__pad[0] != 0 ||
ms->__pad[1] != 0 ||
ms->__pad[2] != 0) {
pr_err("%s: PKCS#7 signature info has unexpected non-zero params\n",
name);
return -EBADMSG;
}
return 0;
}