// 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_KEYRINGstatic struct key *secondary_trusted_keys;#endif#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRINGstatic 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_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 = 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_KEYRINGvoid __init set_platform_trusted_keys(struct key *keyring){	platform_trusted_keys = keyring;}#endif