1/* Module signature checker
 2 *
 3 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
 4 * Written by David Howells (dhowells@redhat.com)
 5 *
 6 * This program is free software; you can redistribute it and/or
 7 * modify it under the terms of the GNU General Public Licence
 8 * as published by the Free Software Foundation; either version
 9 * 2 of the Licence, or (at your option) any later version.
10 */
11
12#include <linux/kernel.h>
13#include <linux/errno.h>
 
 
14#include <linux/string.h>
15#include <keys/system_keyring.h>
16#include <crypto/public_key.h>
17#include "module-internal.h"
18
19enum pkey_id_type {
20	PKEY_ID_PGP,		/* OpenPGP generated key ID */
21	PKEY_ID_X509,		/* X.509 arbitrary subjectKeyIdentifier */
22	PKEY_ID_PKCS7,		/* Signature in PKCS#7 message */
23};
24
25/*
26 * Module signature information block.
27 *
28 * The constituents of the signature section are, in order:
29 *
30 *	- Signer's name
31 *	- Key identifier
32 *	- Signature data
33 *	- Information block
34 */
35struct module_signature {
36	u8	algo;		/* Public-key crypto algorithm [0] */
37	u8	hash;		/* Digest algorithm [0] */
38	u8	id_type;	/* Key identifier type [PKEY_ID_PKCS7] */
39	u8	signer_len;	/* Length of signer's name [0] */
40	u8	key_id_len;	/* Length of key identifier [0] */
41	u8	__pad[3];
42	__be32	sig_len;	/* Length of signature data */
43};
44
45/*
46 * Verify the signature on a module.
47 */
48int mod_verify_sig(const void *mod, unsigned long *_modlen)
49{
50	struct module_signature ms;
51	size_t modlen = *_modlen, sig_len;
 
52
53	pr_devel("==>%s(,%zu)\n", __func__, modlen);
54
55	if (modlen <= sizeof(ms))
56		return -EBADMSG;
57
58	memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms));
59	modlen -= sizeof(ms);
60
61	sig_len = be32_to_cpu(ms.sig_len);
62	if (sig_len >= modlen)
63		return -EBADMSG;
64	modlen -= sig_len;
65	*_modlen = modlen;
66
67	if (ms.id_type != PKEY_ID_PKCS7) {
68		pr_err("Module is not signed with expected PKCS#7 message\n");
69		return -ENOPKG;
70	}
71
72	if (ms.algo != 0 ||
73	    ms.hash != 0 ||
74	    ms.signer_len != 0 ||
75	    ms.key_id_len != 0 ||
76	    ms.__pad[0] != 0 ||
77	    ms.__pad[1] != 0 ||
78	    ms.__pad[2] != 0) {
79		pr_err("PKCS#7 signature info has unexpected non-zero params\n");
80		return -EBADMSG;
81	}
82
83	return system_verify_data(mod, modlen, mod + modlen, sig_len,
84				  VERIFYING_MODULE_SIGNATURE);
 
 
85}

 1// SPDX-License-Identifier: GPL-2.0-or-later
 2/* Module signature checker
 3 *
 4 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
 5 * Written by David Howells (dhowells@redhat.com)
 
 
 
 
 
 6 */
 7
 8#include <linux/kernel.h>
 9#include <linux/errno.h>
10#include <linux/module.h>
11#include <linux/module_signature.h>
12#include <linux/string.h>
13#include <linux/verification.h>
14#include <crypto/public_key.h>
15#include "module-internal.h"
16
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
17/*
18 * Verify the signature on a module.
19 */
20int mod_verify_sig(const void *mod, struct load_info *info)
21{
22	struct module_signature ms;
23	size_t sig_len, modlen = info->len;
24	int ret;
25
26	pr_devel("==>%s(,%zu)\n", __func__, modlen);
27
28	if (modlen <= sizeof(ms))
29		return -EBADMSG;
30
31	memcpy(&ms, mod + (modlen - sizeof(ms)), sizeof(ms));
 
32
33	ret = mod_check_sig(&ms, modlen, info->name);
34	if (ret)
35		return ret;
 
 
36
37	sig_len = be32_to_cpu(ms.sig_len);
38	modlen -= sig_len + sizeof(ms);
39	info->len = modlen;
 
 
 
 
 
 
 
 
 
 
 
 
40
41	return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len,
42				      VERIFY_USE_SECONDARY_KEYRING,
43				      VERIFYING_MODULE_SIGNATURE,
44				      NULL, NULL);
45}