[thirdparty/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/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_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;

/**
 * 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");

	restriction->check = restrict_link_by_builtin_and_secondary_trusted;

	return restriction;
}
#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",
			      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, 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",
			      KUIDT_INIT(0), KGIDT_INIT(0), 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);

/*
 * 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(builtin_trusted_keys, 1),
					   "asymmetric",
					   NULL,
					   p,
					   plen,
					   ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
					   KEY_USR_VIEW | KEY_USR_READ),
					   KEY_ALLOC_NOT_IN_QUOTA |
					   KEY_ALLOC_BUILT_IN |
					   KEY_ALLOC_BYPASS_RESTRICTION);
		if (IS_ERR(key)) {
			pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
			       PTR_ERR(key));
		} else {
			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_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);

	/* 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 = 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:
	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>
817aef26	14	#include <linux/verification.h>
b56e5a17 DH	15	#include <keys/asymmetric-type.h>
b56e5a17 DH	16	#include <keys/system_keyring.h>
091f6e26	17	#include <crypto/pkcs7.h>
b56e5a17	18
d3bfe841 DH	19	static struct key *builtin_trusted_keys;
	20	#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
	21	static struct key *secondary_trusted_keys;
	22	#endif
219a3e86 KS	23	#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
	24	static struct key *platform_trusted_keys;
	25	#endif
b56e5a17 DH	26
b56e5a17 DH	27	extern __initconst const u8 system_certificate_list[];
62226983	28	extern __initconst const unsigned long system_certificate_list_size;
b56e5a17	29
a511e1af	30	/**
d3bfe841	31	* restrict_link_to_builtin_trusted - Restrict keyring addition by built in CA
a511e1af DH	32	*
a511e1af DH	33	* Restrict the addition of keys into a keyring based on the key-to-be-added
d3bfe841	34	* being vouched for by a key in the built in system keyring.
a511e1af	35	*/
aaf66c88	36	int restrict_link_by_builtin_trusted(struct key *dest_keyring,
a511e1af	37	const struct key_type *type,
aaf66c88 MM	38	const union key_payload *payload,
aaf66c88 MM	39	struct key *restriction_key)
a511e1af	40	{
aaf66c88 MM	41	return restrict_link_by_signature(dest_keyring, type, payload,
aaf66c88 MM	42	builtin_trusted_keys);
a511e1af DH	43	}
a511e1af DH	44
d3bfe841 DH	45	#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
	46	/**
	47	* restrict_link_by_builtin_and_secondary_trusted - Restrict keyring
	48	* addition by both builtin and secondary keyrings
	49	*
	50	* Restrict the addition of keys into a keyring based on the key-to-be-added
	51	* being vouched for by a key in either the built-in or the secondary system
	52	* keyrings.
	53	*/
	54	int restrict_link_by_builtin_and_secondary_trusted(
aaf66c88	55	struct key *dest_keyring,
d3bfe841	56	const struct key_type *type,
aaf66c88 MM	57	const union key_payload *payload,
aaf66c88 MM	58	struct key *restrict_key)
d3bfe841 DH	59	{
	60	/* If we have a secondary trusted keyring, then that contains a link
	61	* through to the builtin keyring and the search will follow that link.
	62	*/
	63	if (type == &key_type_keyring &&
aaf66c88	64	dest_keyring == secondary_trusted_keys &&
d3bfe841 DH	65	payload == &builtin_trusted_keys->payload)
	66	/* Allow the builtin keyring to be added to the secondary */
	67	return 0;
	68
aaf66c88 MM	69	return restrict_link_by_signature(dest_keyring, type, payload,
aaf66c88 MM	70	secondary_trusted_keys);
d3bfe841	71	}
2b6aa412 MM	72
	73	/**
	74	* Allocate a struct key_restriction for the "builtin and secondary trust"
	75	* keyring. Only for use in system_trusted_keyring_init().
	76	*/
	77	static __init struct key_restriction *get_builtin_and_secondary_restriction(void)
	78	{
	79	struct key_restriction *restriction;
	80
	81	restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
	82
	83	if (!restriction)
	84	panic("Can't allocate secondary trusted keyring restriction\n");
	85
	86	restriction->check = restrict_link_by_builtin_and_secondary_trusted;
	87
	88	return restriction;
	89	}
d3bfe841 DH	90	#endif
d3bfe841 DH	91
b56e5a17	92	/*
d3bfe841	93	* Create the trusted keyrings
b56e5a17 DH	94	*/
	95	static __init int system_trusted_keyring_init(void)
	96	{
d3bfe841	97	pr_notice("Initialise system trusted keyrings\n");
b56e5a17	98
d3bfe841 DH	99	builtin_trusted_keys =
d3bfe841 DH	100	keyring_alloc(".builtin_trusted_keys",
b56e5a17 DH	101	KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
b56e5a17 DH	102	((KEY_POS_ALL & ~KEY_POS_SETATTR) \|
af34cb0c	103	KEY_USR_VIEW \| KEY_USR_READ \| KEY_USR_SEARCH),
5ac7eace	104	KEY_ALLOC_NOT_IN_QUOTA,
d3bfe841 DH	105	NULL, NULL);
	106	if (IS_ERR(builtin_trusted_keys))
	107	panic("Can't allocate builtin trusted keyring\n");
	108
	109	#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
	110	secondary_trusted_keys =
	111	keyring_alloc(".secondary_trusted_keys",
	112	KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
	113	((KEY_POS_ALL & ~KEY_POS_SETATTR) \|
	114	KEY_USR_VIEW \| KEY_USR_READ \| KEY_USR_SEARCH \|
	115	KEY_USR_WRITE),
	116	KEY_ALLOC_NOT_IN_QUOTA,
2b6aa412	117	get_builtin_and_secondary_restriction(),
d3bfe841 DH	118	NULL);
	119	if (IS_ERR(secondary_trusted_keys))
	120	panic("Can't allocate secondary trusted keyring\n");
	121
	122	if (key_link(secondary_trusted_keys, builtin_trusted_keys) < 0)
	123	panic("Can't link trusted keyrings\n");
	124	#endif
	125
b56e5a17 DH	126	return 0;
	127	}
	128
	129	/*
	130	* Must be initialised before we try and load the keys into the keyring.
	131	*/
	132	device_initcall(system_trusted_keyring_init);
	133
	134	/*
	135	* Load the compiled-in list of X.509 certificates.
	136	*/
	137	static __init int load_system_certificate_list(void)
	138	{
	139	key_ref_t key;
	140	const u8 p, end;
	141	size_t plen;
	142
	143	pr_notice("Loading compiled-in X.509 certificates\n");
	144
b56e5a17	145	p = system_certificate_list;
62226983	146	end = p + system_certificate_list_size;
b56e5a17 DH	147	while (p < end) {
	148	/* Each cert begins with an ASN.1 SEQUENCE tag and must be more
	149	* than 256 bytes in size.
	150	*/
	151	if (end - p < 4)
	152	goto dodgy_cert;
	153	if (p[0] != 0x30 &&
	154	p[1] != 0x82)
	155	goto dodgy_cert;
	156	plen = (p[2] << 8) \| p[3];
	157	plen += 4;
	158	if (plen > end - p)
	159	goto dodgy_cert;
	160
d3bfe841	161	key = key_create_or_update(make_key_ref(builtin_trusted_keys, 1),
b56e5a17 DH	162	"asymmetric",
	163	NULL,
	164	p,
	165	plen,
af34cb0c MZ	166	((KEY_POS_ALL & ~KEY_POS_SETATTR) \|
af34cb0c MZ	167	KEY_USR_VIEW \| KEY_USR_READ),
008643b8	168	KEY_ALLOC_NOT_IN_QUOTA \|
5ac7eace DH	169	KEY_ALLOC_BUILT_IN \|
5ac7eace DH	170	KEY_ALLOC_BYPASS_RESTRICTION);
b56e5a17 DH	171	if (IS_ERR(key)) {
	172	pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
	173	PTR_ERR(key));
	174	} else {
	175	pr_notice("Loaded X.509 cert '%s'\n",
	176	key_ref_to_ptr(key)->description);
	177	key_ref_put(key);
	178	}
	179	p += plen;
	180	}
	181
	182	return 0;
	183
	184	dodgy_cert:
	185	pr_err("Problem parsing in-kernel X.509 certificate list\n");
	186	return 0;
	187	}
	188	late_initcall(load_system_certificate_list);
091f6e26 DH	189
	190	#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
	191
	192	/**
e68503bd DH	193	* verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
e68503bd DH	194	* @data: The data to be verified (NULL if expecting internal data).
091f6e26 DH	195	* @len: Size of @data.
	196	* @raw_pkcs7: The PKCS#7 message that is the signature.
	197	* @pkcs7_len: The size of @raw_pkcs7.
d3bfe841 DH	198	* @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
d3bfe841 DH	199	* (void *)1UL for all trusted keys).
99db4435	200	* @usage: The use to which the key is being put.
e68503bd DH	201	* @view_content: Callback to gain access to content.
e68503bd DH	202	* @ctx: Context for callback.
091f6e26	203	*/
e68503bd DH	204	int verify_pkcs7_signature(const void *data, size_t len,
	205	const void *raw_pkcs7, size_t pkcs7_len,
	206	struct key *trusted_keys,
e68503bd DH	207	enum key_being_used_for usage,
	208	int (view_content)(void ctx,
	209	const void *data, size_t len,
	210	size_t asn1hdrlen),
	211	void *ctx)
091f6e26 DH	212	{
091f6e26 DH	213	struct pkcs7_message *pkcs7;
091f6e26 DH	214	int ret;
	215
	216	pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
	217	if (IS_ERR(pkcs7))
	218	return PTR_ERR(pkcs7);
	219
	220	/* The data should be detached - so we need to supply it. */
e68503bd	221	if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
091f6e26 DH	222	pr_err("PKCS#7 signature with non-detached data\n");
	223	ret = -EBADMSG;
	224	goto error;
	225	}
	226
99db4435	227	ret = pkcs7_verify(pkcs7, usage);
091f6e26 DH	228	if (ret < 0)
	229	goto error;
	230
d3bfe841 DH	231	if (!trusted_keys) {
d3bfe841 DH	232	trusted_keys = builtin_trusted_keys;
817aef26	233	} else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) {
d3bfe841 DH	234	#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
	235	trusted_keys = secondary_trusted_keys;
	236	#else
	237	trusted_keys = builtin_trusted_keys;
	238	#endif
278311e4 KS	239	} else if (trusted_keys == VERIFY_USE_PLATFORM_KEYRING) {
	240	#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
	241	trusted_keys = platform_trusted_keys;
	242	#else
	243	trusted_keys = NULL;
	244	#endif
	245	if (!trusted_keys) {
	246	ret = -ENOKEY;
	247	pr_devel("PKCS#7 platform keyring is not available\n");
	248	goto error;
	249	}
d3bfe841	250	}
bda850cd DH	251	ret = pkcs7_validate_trust(pkcs7, trusted_keys);
	252	if (ret < 0) {
	253	if (ret == -ENOKEY)
278311e4	254	pr_devel("PKCS#7 signature not signed with a trusted key\n");
e68503bd DH	255	goto error;
	256	}
	257
	258	if (view_content) {
	259	size_t asn1hdrlen;
	260
	261	ret = pkcs7_get_content_data(pkcs7, &data, &len, &asn1hdrlen);
	262	if (ret < 0) {
	263	if (ret == -ENODATA)
	264	pr_devel("PKCS#7 message does not contain data\n");
	265	goto error;
	266	}
	267
	268	ret = view_content(ctx, data, len, asn1hdrlen);
091f6e26 DH	269	}
	270
	271	error:
	272	pkcs7_free_message(pkcs7);
	273	pr_devel("<==%s() = %d\n", __func__, ret);
	274	return ret;
	275	}
e68503bd	276	EXPORT_SYMBOL_GPL(verify_pkcs7_signature);
091f6e26 DH	277
091f6e26 DH	278	#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
219a3e86 KS	279
	280	#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING
	281	void __init set_platform_trusted_keys(struct key *keyring)
	282	{
	283	platform_trusted_keys = keyring;
	284	}
	285	#endif