Root/kernel/system_keyring.c

1/* System trusted keyring for trusted public keys
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/export.h>
13#include <linux/kernel.h>
14#include <linux/sched.h>
15#include <linux/cred.h>
16#include <linux/err.h>
17#include <keys/asymmetric-type.h>
18#include <keys/system_keyring.h>
19#include "module-internal.h"
20
21struct key *system_trusted_keyring;
22EXPORT_SYMBOL_GPL(system_trusted_keyring);
23
24extern __initconst const u8 system_certificate_list[];
25extern __initconst const unsigned long system_certificate_list_size;
26
27/*
28 * Load the compiled-in keys
29 */
30static __init int system_trusted_keyring_init(void)
31{
32    pr_notice("Initialise system trusted keyring\n");
33
34    system_trusted_keyring =
35        keyring_alloc(".system_keyring",
36                  KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
37                  ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
38                  KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
39                  KEY_ALLOC_NOT_IN_QUOTA, NULL);
40    if (IS_ERR(system_trusted_keyring))
41        panic("Can't allocate system trusted keyring\n");
42
43    set_bit(KEY_FLAG_TRUSTED_ONLY, &system_trusted_keyring->flags);
44    return 0;
45}
46
47/*
48 * Must be initialised before we try and load the keys into the keyring.
49 */
50device_initcall(system_trusted_keyring_init);
51
52/*
53 * Load the compiled-in list of X.509 certificates.
54 */
55static __init int load_system_certificate_list(void)
56{
57    key_ref_t key;
58    const u8 *p, *end;
59    size_t plen;
60
61    pr_notice("Loading compiled-in X.509 certificates\n");
62
63    p = system_certificate_list;
64    end = p + system_certificate_list_size;
65    while (p < end) {
66        /* Each cert begins with an ASN.1 SEQUENCE tag and must be more
67         * than 256 bytes in size.
68         */
69        if (end - p < 4)
70            goto dodgy_cert;
71        if (p[0] != 0x30 &&
72            p[1] != 0x82)
73            goto dodgy_cert;
74        plen = (p[2] << 8) | p[3];
75        plen += 4;
76        if (plen > end - p)
77            goto dodgy_cert;
78
79        key = key_create_or_update(make_key_ref(system_trusted_keyring, 1),
80                       "asymmetric",
81                       NULL,
82                       p,
83                       plen,
84                       ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
85                       KEY_USR_VIEW | KEY_USR_READ),
86                       KEY_ALLOC_NOT_IN_QUOTA |
87                       KEY_ALLOC_TRUSTED);
88        if (IS_ERR(key)) {
89            pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
90                   PTR_ERR(key));
91        } else {
92            pr_notice("Loaded X.509 cert '%s'\n",
93                  key_ref_to_ptr(key)->description);
94            key_ref_put(key);
95        }
96        p += plen;
97    }
98
99    return 0;
100
101dodgy_cert:
102    pr_err("Problem parsing in-kernel X.509 certificate list\n");
103    return 0;
104}
105late_initcall(load_system_certificate_list);
106

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