[people/ms/linux.git] / certs / system_keyring.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* System trusted keyring for trusted public keys
 *
 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 */

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

static struct key *builtin_trusted_keys;
#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
static struct key *secondary_trusted_keys;
#endif
#ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
static struct key *machine_trusted_keys;
#endif
#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
static struct key *platform_trusted_keys;
#endif

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

/**
 * restrict_link_to_builtin_trusted - Restrict keyring addition by built in CA
 *
 * Restrict the addition of keys into a keyring based on the key-to-be-added
 * being vouched for by a key in the built in system keyring.
 */
int restrict_link_by_builtin_trusted(struct key *dest_keyring,
				     const struct key_type *type,
				     const union key_payload *payload,
				     struct key *restriction_key)
{
	return restrict_link_by_signature(dest_keyring, type, payload,
					  builtin_trusted_keys);
}

#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
/**
 * restrict_link_by_builtin_and_secondary_trusted - Restrict keyring
 *   addition by both builtin and secondary keyrings
 *
 * Restrict the addition of keys into a keyring based on the key-to-be-added
 * being vouched for by a key in either the built-in or the secondary system
 * keyrings.
 */
int restrict_link_by_builtin_and_secondary_trusted(
	struct key *dest_keyring,
	const struct key_type *type,
	const union key_payload *payload,
	struct key *restrict_key)
{
	/* If we have a secondary trusted keyring, then that contains a link
	 * through to the builtin keyring and the search will follow that link.
	 */
	if (type == &key_type_keyring &&
	    dest_keyring == secondary_trusted_keys &&
	    payload == &builtin_trusted_keys->payload)
		/* Allow the builtin keyring to be added to the secondary */
		return 0;

	return restrict_link_by_signature(dest_keyring, type, payload,
					  secondary_trusted_keys);
}

/**
 * Allocate a struct key_restriction for the "builtin and secondary trust"
 * keyring. Only for use in system_trusted_keyring_init().
 */
static __init struct key_restriction *get_builtin_and_secondary_restriction(void)
{
	struct key_restriction *restriction;

	restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);

	if (!restriction)
		panic("Can't allocate secondary trusted keyring restriction\n");

	if (IS_ENABLED(CONFIG_INTEGRITY_MACHINE_KEYRING))
		restriction->check = restrict_link_by_builtin_secondary_and_machine;
	else
		restriction->check = restrict_link_by_builtin_and_secondary_trusted;

	return restriction;
}
#endif
#ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
void __init set_machine_trusted_keys(struct key *keyring)
{
	machine_trusted_keys = keyring;

	if (key_link(secondary_trusted_keys, machine_trusted_keys) < 0)
		panic("Can't link (machine) trusted keyrings\n");
}

/**
 * restrict_link_by_builtin_secondary_and_machine - Restrict keyring addition.
 * @dest_keyring: Keyring being linked to.
 * @type: The type of key being added.
 * @payload: The payload of the new key.
 * @restrict_key: A ring of keys that can be used to vouch for the new cert.
 *
 * Restrict the addition of keys into a keyring based on the key-to-be-added
 * being vouched for by a key in either the built-in, the secondary, or
 * the machine keyrings.
 */
int restrict_link_by_builtin_secondary_and_machine(
	struct key *dest_keyring,
	const struct key_type *type,
	const union key_payload *payload,
	struct key *restrict_key)
{
	if (machine_trusted_keys && type == &key_type_keyring &&
	    dest_keyring == secondary_trusted_keys &&
	    payload == &machine_trusted_keys->payload)
		/* Allow the machine keyring to be added to the secondary */
		return 0;

	return restrict_link_by_builtin_and_secondary_trusted(dest_keyring, type,
							      payload, restrict_key);
}
#endif

/*
 * Create the trusted keyrings
 */
static __init int system_trusted_keyring_init(void)
{
	pr_notice("Initialise system trusted keyrings\n");

	builtin_trusted_keys =
		keyring_alloc(".builtin_trusted_keys",
			      GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
			      ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
			      KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
			      KEY_ALLOC_NOT_IN_QUOTA,
			      NULL, NULL);
	if (IS_ERR(builtin_trusted_keys))
		panic("Can't allocate builtin trusted keyring\n");

#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
	secondary_trusted_keys =
		keyring_alloc(".secondary_trusted_keys",
			      GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
			      ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
			       KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH |
			       KEY_USR_WRITE),
			      KEY_ALLOC_NOT_IN_QUOTA,
			      get_builtin_and_secondary_restriction(),
			      NULL);
	if (IS_ERR(secondary_trusted_keys))
		panic("Can't allocate secondary trusted keyring\n");

	if (key_link(secondary_trusted_keys, builtin_trusted_keys) < 0)
		panic("Can't link trusted keyrings\n");
#endif

	return 0;
}

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

__init int load_module_cert(struct key *keyring)
{
	if (!IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG))
		return 0;

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

	return x509_load_certificate_list(system_certificate_list,
					  module_cert_size, keyring);
}

/*
 * Load the compiled-in list of X.509 certificates.
 */
static __init int load_system_certificate_list(void)
{
	const u8 *p;
	unsigned long size;

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

#ifdef CONFIG_MODULE_SIG
	p = system_certificate_list;
	size = system_certificate_list_size;
#else
	p = system_certificate_list + module_cert_size;
	size = system_certificate_list_size - module_cert_size;
#endif

	return x509_load_certificate_list(p, size, builtin_trusted_keys);
}
late_initcall(load_system_certificate_list);

#ifdef CONFIG_SYSTEM_DATA_VERIFICATION

/**
 * verify_pkcs7_message_sig - Verify a PKCS#7-based signature on system data.
 * @data: The data to be verified (NULL if expecting internal data).
 * @len: Size of @data.
 * @pkcs7: The PKCS#7 message that is the signature.
 * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
 *					(void *)1UL for all trusted keys).
 * @usage: The use to which the key is being put.
 * @view_content: Callback to gain access to content.
 * @ctx: Context for callback.
 */
int verify_pkcs7_message_sig(const void *data, size_t len,
			     struct pkcs7_message *pkcs7,
			     struct key *trusted_keys,
			     enum key_being_used_for usage,
			     int (*view_content)(void *ctx,
						 const void *data, size_t len,
						 size_t asn1hdrlen),
			     void *ctx)
{
	int ret;

	/* The data should be detached - so we need to supply it. */
	if (data && 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;

	if (!trusted_keys) {
		trusted_keys = builtin_trusted_keys;
	} else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) {
#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
		trusted_keys = secondary_trusted_keys;
#else
		trusted_keys = builtin_trusted_keys;
#endif
	} else if (trusted_keys == VERIFY_USE_PLATFORM_KEYRING) {
#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
		trusted_keys = platform_trusted_keys;
#else
		trusted_keys = NULL;
#endif
		if (!trusted_keys) {
			ret = -ENOKEY;
			pr_devel("PKCS#7 platform keyring is not available\n");
			goto error;
		}

		ret = is_key_on_revocation_list(pkcs7);
		if (ret != -ENOKEY) {
			pr_devel("PKCS#7 platform key is on revocation list\n");
			goto error;
		}
	}
	ret = pkcs7_validate_trust(pkcs7, trusted_keys);
	if (ret < 0) {
		if (ret == -ENOKEY)
			pr_devel("PKCS#7 signature not signed with a trusted key\n");
		goto error;
	}

	if (view_content) {
		size_t asn1hdrlen;

		ret = pkcs7_get_content_data(pkcs7, &data, &len, &asn1hdrlen);
		if (ret < 0) {
			if (ret == -ENODATA)
				pr_devel("PKCS#7 message does not contain data\n");
			goto error;
		}

		ret = view_content(ctx, data, len, asn1hdrlen);
	}

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

/**
 * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
 * @data: The data to be verified (NULL if expecting internal data).
 * @len: Size of @data.
 * @raw_pkcs7: The PKCS#7 message that is the signature.
 * @pkcs7_len: The size of @raw_pkcs7.
 * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
 *					(void *)1UL for all trusted keys).
 * @usage: The use to which the key is being put.
 * @view_content: Callback to gain access to content.
 * @ctx: Context for callback.
 */
int verify_pkcs7_signature(const void *data, size_t len,
			   const void *raw_pkcs7, size_t pkcs7_len,
			   struct key *trusted_keys,
			   enum key_being_used_for usage,
			   int (*view_content)(void *ctx,
					       const void *data, size_t len,
					       size_t asn1hdrlen),
			   void *ctx)
{
	struct pkcs7_message *pkcs7;
	int ret;

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

	ret = verify_pkcs7_message_sig(data, len, pkcs7, trusted_keys, usage,
				       view_content, ctx);

	pkcs7_free_message(pkcs7);
	pr_devel("<==%s() = %d\n", __func__, ret);
	return ret;
}
EXPORT_SYMBOL_GPL(verify_pkcs7_signature);

#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */

#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
void __init set_platform_trusted_keys(struct key *keyring)
{
	platform_trusted_keys = keyring;
}
#endif
Commit	Line	Data
b4d0d230	1	// SPDX-License-Identifier: GPL-2.0-or-later
b56e5a17 DH	2	/* System trusted keyring for trusted public keys
	3	*
	4	* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
	5	* Written by David Howells (dhowells@redhat.com)
b56e5a17 DH	6	*/
	7
	8	#include <linux/export.h>
	9	#include <linux/kernel.h>
	10	#include <linux/sched.h>
	11	#include <linux/cred.h>
	12	#include <linux/err.h>
2b6aa412	13	#include <linux/slab.h>
a6cb0ab7	14	#include <linux/uidgid.h>
817aef26	15	#include <linux/verification.h>
b56e5a17 DH	16	#include <keys/asymmetric-type.h>
b56e5a17 DH	17	#include <keys/system_keyring.h>
091f6e26	18	#include <crypto/pkcs7.h>
b56e5a17	19
d3bfe841 DH	20	static struct key *builtin_trusted_keys;
	21	#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
	22	static struct key *secondary_trusted_keys;
	23	#endif
56edb6c2 ES	24	#ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
	25	static struct key *machine_trusted_keys;
	26	#endif
219a3e86 KS	27	#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
	28	static struct key *platform_trusted_keys;
	29	#endif
b56e5a17 DH	30
b56e5a17 DH	31	extern __initconst const u8 system_certificate_list[];
62226983	32	extern __initconst const unsigned long system_certificate_list_size;
6cbdfb3d	33	extern __initconst const unsigned long module_cert_size;
b56e5a17	34
a511e1af	35	/**
d3bfe841	36	* restrict_link_to_builtin_trusted - Restrict keyring addition by built in CA
a511e1af DH	37	*
a511e1af DH	38	* Restrict the addition of keys into a keyring based on the key-to-be-added
d3bfe841	39	* being vouched for by a key in the built in system keyring.
a511e1af	40	*/
aaf66c88	41	int restrict_link_by_builtin_trusted(struct key *dest_keyring,
a511e1af	42	const struct key_type *type,
aaf66c88 MM	43	const union key_payload *payload,
aaf66c88 MM	44	struct key *restriction_key)
a511e1af	45	{
aaf66c88 MM	46	return restrict_link_by_signature(dest_keyring, type, payload,
aaf66c88 MM	47	builtin_trusted_keys);
a511e1af DH	48	}
a511e1af DH	49
d3bfe841 DH	50	#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
	51	/**
	52	* restrict_link_by_builtin_and_secondary_trusted - Restrict keyring
	53	* addition by both builtin and secondary keyrings
	54	*
	55	* Restrict the addition of keys into a keyring based on the key-to-be-added
	56	* being vouched for by a key in either the built-in or the secondary system
	57	* keyrings.
	58	*/
	59	int restrict_link_by_builtin_and_secondary_trusted(
aaf66c88	60	struct key *dest_keyring,
d3bfe841	61	const struct key_type *type,
aaf66c88 MM	62	const union key_payload *payload,
aaf66c88 MM	63	struct key *restrict_key)
d3bfe841 DH	64	{
	65	/* If we have a secondary trusted keyring, then that contains a link
	66	* through to the builtin keyring and the search will follow that link.
	67	*/
	68	if (type == &key_type_keyring &&
aaf66c88	69	dest_keyring == secondary_trusted_keys &&
d3bfe841 DH	70	payload == &builtin_trusted_keys->payload)
	71	/* Allow the builtin keyring to be added to the secondary */
	72	return 0;
	73
aaf66c88 MM	74	return restrict_link_by_signature(dest_keyring, type, payload,
aaf66c88 MM	75	secondary_trusted_keys);
d3bfe841	76	}
2b6aa412 MM	77
	78	/**
	79	* Allocate a struct key_restriction for the "builtin and secondary trust"
	80	* keyring. Only for use in system_trusted_keyring_init().
	81	*/
	82	static __init struct key_restriction *get_builtin_and_secondary_restriction(void)
	83	{
	84	struct key_restriction *restriction;
	85
	86	restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
	87
	88	if (!restriction)
	89	panic("Can't allocate secondary trusted keyring restriction\n");
	90
087aa4ed ES	91	if (IS_ENABLED(CONFIG_INTEGRITY_MACHINE_KEYRING))
	92	restriction->check = restrict_link_by_builtin_secondary_and_machine;
	93	else
	94	restriction->check = restrict_link_by_builtin_and_secondary_trusted;
2b6aa412 MM	95
	96	return restriction;
	97	}
d3bfe841	98	#endif
56edb6c2 ES	99	#ifdef CONFIG_INTEGRITY_MACHINE_KEYRING
	100	void __init set_machine_trusted_keys(struct key *keyring)
	101	{
	102	machine_trusted_keys = keyring;
087aa4ed ES	103
	104	if (key_link(secondary_trusted_keys, machine_trusted_keys) < 0)
	105	panic("Can't link (machine) trusted keyrings\n");
	106	}
	107
	108	/**
	109	* restrict_link_by_builtin_secondary_and_machine - Restrict keyring addition.
	110	* @dest_keyring: Keyring being linked to.
	111	* @type: The type of key being added.
	112	* @payload: The payload of the new key.
	113	* @restrict_key: A ring of keys that can be used to vouch for the new cert.
	114	*
	115	* Restrict the addition of keys into a keyring based on the key-to-be-added
	116	* being vouched for by a key in either the built-in, the secondary, or
	117	* the machine keyrings.
	118	*/
	119	int restrict_link_by_builtin_secondary_and_machine(
	120	struct key *dest_keyring,
	121	const struct key_type *type,
	122	const union key_payload *payload,
	123	struct key *restrict_key)
	124	{
	125	if (machine_trusted_keys && type == &key_type_keyring &&
	126	dest_keyring == secondary_trusted_keys &&
	127	payload == &machine_trusted_keys->payload)
	128	/* Allow the machine keyring to be added to the secondary */
	129	return 0;
	130
	131	return restrict_link_by_builtin_and_secondary_trusted(dest_keyring, type,
	132	payload, restrict_key);
56edb6c2 ES	133	}
56edb6c2 ES	134	#endif
d3bfe841	135
b56e5a17	136	/*
d3bfe841	137	* Create the trusted keyrings
b56e5a17 DH	138	*/
	139	static __init int system_trusted_keyring_init(void)
	140	{
d3bfe841	141	pr_notice("Initialise system trusted keyrings\n");
b56e5a17	142
d3bfe841 DH	143	builtin_trusted_keys =
d3bfe841 DH	144	keyring_alloc(".builtin_trusted_keys",
a6cb0ab7	145	GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
028db3e2 LT	146	((KEY_POS_ALL & ~KEY_POS_SETATTR) \|
	147	KEY_USR_VIEW \| KEY_USR_READ \| KEY_USR_SEARCH),
	148	KEY_ALLOC_NOT_IN_QUOTA,
d3bfe841 DH	149	NULL, NULL);
	150	if (IS_ERR(builtin_trusted_keys))
	151	panic("Can't allocate builtin trusted keyring\n");
	152
	153	#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
	154	secondary_trusted_keys =
	155	keyring_alloc(".secondary_trusted_keys",
a6cb0ab7	156	GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(),
028db3e2 LT	157	((KEY_POS_ALL & ~KEY_POS_SETATTR) \|
	158	KEY_USR_VIEW \| KEY_USR_READ \| KEY_USR_SEARCH \|
	159	KEY_USR_WRITE),
	160	KEY_ALLOC_NOT_IN_QUOTA,
2b6aa412	161	get_builtin_and_secondary_restriction(),
d3bfe841 DH	162	NULL);
	163	if (IS_ERR(secondary_trusted_keys))
	164	panic("Can't allocate secondary trusted keyring\n");
	165
	166	if (key_link(secondary_trusted_keys, builtin_trusted_keys) < 0)
	167	panic("Can't link trusted keyrings\n");
	168	#endif
	169
b56e5a17 DH	170	return 0;
	171	}
	172
	173	/*
	174	* Must be initialised before we try and load the keys into the keyring.
	175	*/
	176	device_initcall(system_trusted_keyring_init);
	177
6cbdfb3d NJ	178	__init int load_module_cert(struct key *keyring)
6cbdfb3d NJ	179	{
6cbdfb3d NJ	180	if (!IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG))
	181	return 0;
	182
	183	pr_notice("Loading compiled-in module X.509 certificates\n");
	184
60050ffe DH	185	return x509_load_certificate_list(system_certificate_list,
60050ffe DH	186	module_cert_size, keyring);
6cbdfb3d NJ	187	}
6cbdfb3d NJ	188
b56e5a17 DH	189	/*
	190	* Load the compiled-in list of X.509 certificates.
	191	*/
	192	static __init int load_system_certificate_list(void)
	193	{
e6f0bf09	194	const u8 *p;
6cbdfb3d NJ	195	unsigned long size;
6cbdfb3d NJ	196
b56e5a17 DH	197	pr_notice("Loading compiled-in X.509 certificates\n");
b56e5a17 DH	198
6cbdfb3d NJ	199	#ifdef CONFIG_MODULE_SIG
	200	p = system_certificate_list;
	201	size = system_certificate_list_size;
	202	#else
	203	p = system_certificate_list + module_cert_size;
	204	size = system_certificate_list_size - module_cert_size;
	205	#endif
	206
60050ffe	207	return x509_load_certificate_list(p, size, builtin_trusted_keys);
b56e5a17 DH	208	}
b56e5a17 DH	209	late_initcall(load_system_certificate_list);
091f6e26 DH	210
	211	#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
	212
	213	/**
2a7bf671	214	* verify_pkcs7_message_sig - Verify a PKCS#7-based signature on system data.
e68503bd	215	* @data: The data to be verified (NULL if expecting internal data).
091f6e26	216	* @len: Size of @data.
2a7bf671	217	* @pkcs7: The PKCS#7 message that is the signature.
d3bfe841 DH	218	* @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
d3bfe841 DH	219	* (void *)1UL for all trusted keys).
99db4435	220	* @usage: The use to which the key is being put.
e68503bd DH	221	* @view_content: Callback to gain access to content.
e68503bd DH	222	* @ctx: Context for callback.
091f6e26	223	*/
2a7bf671 TJB	224	int verify_pkcs7_message_sig(const void *data, size_t len,
	225	struct pkcs7_message *pkcs7,
	226	struct key *trusted_keys,
	227	enum key_being_used_for usage,
	228	int (view_content)(void ctx,
	229	const void *data, size_t len,
	230	size_t asn1hdrlen),
	231	void *ctx)
091f6e26	232	{
091f6e26 DH	233	int ret;
091f6e26 DH	234
091f6e26	235	/* The data should be detached - so we need to supply it. */
e68503bd	236	if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
091f6e26 DH	237	pr_err("PKCS#7 signature with non-detached data\n");
	238	ret = -EBADMSG;
	239	goto error;
	240	}
	241
99db4435	242	ret = pkcs7_verify(pkcs7, usage);
091f6e26 DH	243	if (ret < 0)
	244	goto error;
	245
d3bfe841 DH	246	if (!trusted_keys) {
d3bfe841 DH	247	trusted_keys = builtin_trusted_keys;
817aef26	248	} else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) {
d3bfe841 DH	249	#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
	250	trusted_keys = secondary_trusted_keys;
	251	#else
	252	trusted_keys = builtin_trusted_keys;
	253	#endif
278311e4 KS	254	} else if (trusted_keys == VERIFY_USE_PLATFORM_KEYRING) {
	255	#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
	256	trusted_keys = platform_trusted_keys;
	257	#else
	258	trusted_keys = NULL;
	259	#endif
	260	if (!trusted_keys) {
	261	ret = -ENOKEY;
	262	pr_devel("PKCS#7 platform keyring is not available\n");
	263	goto error;
	264	}
56c58126 ES	265
	266	ret = is_key_on_revocation_list(pkcs7);
	267	if (ret != -ENOKEY) {
	268	pr_devel("PKCS#7 platform key is on revocation list\n");
	269	goto error;
	270	}
d3bfe841	271	}
bda850cd DH	272	ret = pkcs7_validate_trust(pkcs7, trusted_keys);
	273	if (ret < 0) {
	274	if (ret == -ENOKEY)
278311e4	275	pr_devel("PKCS#7 signature not signed with a trusted key\n");
e68503bd DH	276	goto error;
	277	}
	278
	279	if (view_content) {
	280	size_t asn1hdrlen;
	281
	282	ret = pkcs7_get_content_data(pkcs7, &data, &len, &asn1hdrlen);
	283	if (ret < 0) {
	284	if (ret == -ENODATA)
	285	pr_devel("PKCS#7 message does not contain data\n");
	286	goto error;
	287	}
	288
	289	ret = view_content(ctx, data, len, asn1hdrlen);
091f6e26 DH	290	}
	291
	292	error:
2a7bf671 TJB	293	pr_devel("<==%s() = %d\n", __func__, ret);
	294	return ret;
	295	}
	296
	297	/**
	298	* verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
	299	* @data: The data to be verified (NULL if expecting internal data).
	300	* @len: Size of @data.
	301	* @raw_pkcs7: The PKCS#7 message that is the signature.
	302	* @pkcs7_len: The size of @raw_pkcs7.
	303	* @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
	304	* (void *)1UL for all trusted keys).
	305	* @usage: The use to which the key is being put.
	306	* @view_content: Callback to gain access to content.
	307	* @ctx: Context for callback.
	308	*/
	309	int verify_pkcs7_signature(const void *data, size_t len,
	310	const void *raw_pkcs7, size_t pkcs7_len,
	311	struct key *trusted_keys,
	312	enum key_being_used_for usage,
	313	int (view_content)(void ctx,
	314	const void *data, size_t len,
	315	size_t asn1hdrlen),
	316	void *ctx)
	317	{
	318	struct pkcs7_message *pkcs7;
	319	int ret;
	320
	321	pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
	322	if (IS_ERR(pkcs7))
	323	return PTR_ERR(pkcs7);
	324
	325	ret = verify_pkcs7_message_sig(data, len, pkcs7, trusted_keys, usage,
	326	view_content, ctx);
	327
091f6e26 DH	328	pkcs7_free_message(pkcs7);
	329	pr_devel("<==%s() = %d\n", __func__, ret);
	330	return ret;
	331	}
e68503bd	332	EXPORT_SYMBOL_GPL(verify_pkcs7_signature);
091f6e26 DH	333
091f6e26 DH	334	#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
219a3e86 KS	335
	336	#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
	337	void __init set_platform_trusted_keys(struct key *keyring)
	338	{
	339	platform_trusted_keys = keyring;
	340	}
	341	#endif