[linux-2.6-block.git] / certs / system_keyring.c

/* System trusted keyring for trusted public keys
 *
 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 *
 * 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.
 */

#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/cred.h>
#include <linux/err.h>
#include <keys/asymmetric-type.h>
#include <keys/system_keyring.h>
#include <crypto/pkcs7.h>

struct key *system_trusted_keyring;
EXPORT_SYMBOL_GPL(system_trusted_keyring);

extern __initconst const u8 system_certificate_list[];
extern __initconst const unsigned long system_certificate_list_size;

/*
 * Load the compiled-in keys
 */
static __init int system_trusted_keyring_init(void)
{
	pr_notice("Initialise system trusted keyring\n");

	system_trusted_keyring =
		keyring_alloc(".system_keyring",
			      KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
			      ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
			      KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
			      KEY_ALLOC_NOT_IN_QUOTA, NULL);
	if (IS_ERR(system_trusted_keyring))
		panic("Can't allocate system trusted keyring\n");

	set_bit(KEY_FLAG_TRUSTED_ONLY, &system_trusted_keyring->flags);
	return 0;
}

/*
 * Must be initialised before we try and load the keys into the keyring.
 */
device_initcall(system_trusted_keyring_init);

/*
 * Load the compiled-in list of X.509 certificates.
 */
static __init int load_system_certificate_list(void)
{
	key_ref_t key;
	const u8 *p, *end;
	size_t plen;

	pr_notice("Loading compiled-in X.509 certificates\n");

	p = system_certificate_list;
	end = p + system_certificate_list_size;
	while (p < end) {
		/* Each cert begins with an ASN.1 SEQUENCE tag and must be more
		 * than 256 bytes in size.
		 */
		if (end - p < 4)
			goto dodgy_cert;
		if (p[0] != 0x30 &&
		    p[1] != 0x82)
			goto dodgy_cert;
		plen = (p[2] << 8) | p[3];
		plen += 4;
		if (plen > end - p)
			goto dodgy_cert;

		key = key_create_or_update(make_key_ref(system_trusted_keyring, 1),
					   "asymmetric",
					   NULL,
					   p,
					   plen,
					   ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
					   KEY_USR_VIEW | KEY_USR_READ),
					   KEY_ALLOC_NOT_IN_QUOTA |
					   KEY_ALLOC_TRUSTED);
		if (IS_ERR(key)) {
			pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
			       PTR_ERR(key));
		} else {
			set_bit(KEY_FLAG_BUILTIN, &key_ref_to_ptr(key)->flags);
			pr_notice("Loaded X.509 cert '%s'\n",
				  key_ref_to_ptr(key)->description);
			key_ref_put(key);
		}
		p += plen;
	}

	return 0;

dodgy_cert:
	pr_err("Problem parsing in-kernel X.509 certificate list\n");
	return 0;
}
late_initcall(load_system_certificate_list);

#ifdef CONFIG_SYSTEM_DATA_VERIFICATION

/**
 * Verify a PKCS#7-based signature on system data.
 * @data: The data to be verified.
 * @len: Size of @data.
 * @raw_pkcs7: The PKCS#7 message that is the signature.
 * @pkcs7_len: The size of @raw_pkcs7.
 * @usage: The use to which the key is being put.
 */
int system_verify_data(const void *data, unsigned long len,
		       const void *raw_pkcs7, size_t pkcs7_len,
		       enum key_being_used_for usage)
{
	struct pkcs7_message *pkcs7;
	bool trusted;
	int ret;

	pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
	if (IS_ERR(pkcs7))
		return PTR_ERR(pkcs7);

	/* The data should be detached - so we need to supply it. */
	if (pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
		pr_err("PKCS#7 signature with non-detached data\n");
		ret = -EBADMSG;
		goto error;
	}

	ret = pkcs7_verify(pkcs7, usage);
	if (ret < 0)
		goto error;

	ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
	if (ret < 0)
		goto error;

	if (!trusted) {
		pr_err("PKCS#7 signature not signed with a trusted key\n");
		ret = -ENOKEY;
	}

error:
	pkcs7_free_message(pkcs7);
	pr_devel("<==%s() = %d\n", __func__, ret);
	return ret;
}
EXPORT_SYMBOL_GPL(system_verify_data);

#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
Commit	Line	Data
b56e5a17 DH	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>
091f6e26	19	#include <crypto/pkcs7.h>
b56e5a17 DH	20
	21	struct key *system_trusted_keyring;
	22	EXPORT_SYMBOL_GPL(system_trusted_keyring);
	23
	24	extern __initconst const u8 system_certificate_list[];
62226983	25	extern __initconst const unsigned long system_certificate_list_size;
b56e5a17 DH	26
	27	/*
	28	* Load the compiled-in keys
	29	*/
	30	static __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) \|
af34cb0c	38	KEY_USR_VIEW \| KEY_USR_READ \| KEY_USR_SEARCH),
b56e5a17 DH	39	KEY_ALLOC_NOT_IN_QUOTA, NULL);
	40	if (IS_ERR(system_trusted_keyring))
	41	panic("Can't allocate system trusted keyring\n");
	42
008643b8	43	set_bit(KEY_FLAG_TRUSTED_ONLY, &system_trusted_keyring->flags);
b56e5a17 DH	44	return 0;
	45	}
	46
	47	/*
	48	* Must be initialised before we try and load the keys into the keyring.
	49	*/
	50	device_initcall(system_trusted_keyring_init);
	51
	52	/*
	53	* Load the compiled-in list of X.509 certificates.
	54	*/
	55	static __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
b56e5a17	63	p = system_certificate_list;
62226983	64	end = p + system_certificate_list_size;
b56e5a17 DH	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,
af34cb0c MZ	84	((KEY_POS_ALL & ~KEY_POS_SETATTR) \|
af34cb0c MZ	85	KEY_USR_VIEW \| KEY_USR_READ),
008643b8 DH	86	KEY_ALLOC_NOT_IN_QUOTA \|
008643b8 DH	87	KEY_ALLOC_TRUSTED);
b56e5a17 DH	88	if (IS_ERR(key)) {
	89	pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
	90	PTR_ERR(key));
	91	} else {
32c4741c	92	set_bit(KEY_FLAG_BUILTIN, &key_ref_to_ptr(key)->flags);
b56e5a17 DH	93	pr_notice("Loaded X.509 cert '%s'\n",
	94	key_ref_to_ptr(key)->description);
	95	key_ref_put(key);
	96	}
	97	p += plen;
	98	}
	99
	100	return 0;
	101
	102	dodgy_cert:
	103	pr_err("Problem parsing in-kernel X.509 certificate list\n");
	104	return 0;
	105	}
	106	late_initcall(load_system_certificate_list);
091f6e26 DH	107
	108	#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
	109
	110	/**
	111	* Verify a PKCS#7-based signature on system data.
	112	* @data: The data to be verified.
	113	* @len: Size of @data.
	114	* @raw_pkcs7: The PKCS#7 message that is the signature.
	115	* @pkcs7_len: The size of @raw_pkcs7.
99db4435	116	* @usage: The use to which the key is being put.
091f6e26 DH	117	*/
091f6e26 DH	118	int system_verify_data(const void *data, unsigned long len,
99db4435 DH	119	const void *raw_pkcs7, size_t pkcs7_len,
99db4435 DH	120	enum key_being_used_for usage)
091f6e26 DH	121	{
	122	struct pkcs7_message *pkcs7;
	123	bool trusted;
	124	int ret;
	125
	126	pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
	127	if (IS_ERR(pkcs7))
	128	return PTR_ERR(pkcs7);
	129
	130	/* The data should be detached - so we need to supply it. */
	131	if (pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
	132	pr_err("PKCS#7 signature with non-detached data\n");
	133	ret = -EBADMSG;
	134	goto error;
	135	}
	136
99db4435	137	ret = pkcs7_verify(pkcs7, usage);
091f6e26 DH	138	if (ret < 0)
	139	goto error;
	140
	141	ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
	142	if (ret < 0)
	143	goto error;
	144
	145	if (!trusted) {
	146	pr_err("PKCS#7 signature not signed with a trusted key\n");
	147	ret = -ENOKEY;
	148	}
	149
	150	error:
	151	pkcs7_free_message(pkcs7);
	152	pr_devel("<==%s() = %d\n", __func__, ret);
	153	return ret;
	154	}
	155	EXPORT_SYMBOL_GPL(system_verify_data);
	156
	157	#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */