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}