linux/kernel/module_signing.c
Thomas Gleixner b4d0d230cc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 114 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:27:11 +02:00

86 lines
2.1 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/string.h>
#include <linux/verification.h>
#include <crypto/public_key.h>
#include "module-internal.h"
enum pkey_id_type {
PKEY_ID_PGP, /* OpenPGP generated key ID */
PKEY_ID_X509, /* X.509 arbitrary subjectKeyIdentifier */
PKEY_ID_PKCS7, /* Signature in PKCS#7 message */
};
/*
* 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 {
u8 algo; /* Public-key crypto algorithm [0] */
u8 hash; /* Digest algorithm [0] */
u8 id_type; /* Key identifier type [PKEY_ID_PKCS7] */
u8 signer_len; /* Length of signer's name [0] */
u8 key_id_len; /* Length of key identifier [0] */
u8 __pad[3];
__be32 sig_len; /* Length of signature data */
};
/*
* 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;
pr_devel("==>%s(,%zu)\n", __func__, modlen);
if (modlen <= sizeof(ms))
return -EBADMSG;
memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms));
modlen -= sizeof(ms);
sig_len = be32_to_cpu(ms.sig_len);
if (sig_len >= modlen)
return -EBADMSG;
modlen -= sig_len;
info->len = modlen;
if (ms.id_type != PKEY_ID_PKCS7) {
pr_err("%s: Module is not signed with expected PKCS#7 message\n",
info->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",
info->name);
return -EBADMSG;
}
return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len,
VERIFY_USE_SECONDARY_KEYRING,
VERIFYING_MODULE_SIGNATURE,
NULL, NULL);
}