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299 lines
8.5 KiB
299 lines
8.5 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* System trusted keyring for trusted public keys |
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* |
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* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved. |
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* Written by David Howells ([email protected]) |
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*/ |
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#include <linux/export.h> |
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#include <linux/kernel.h> |
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#include <linux/sched.h> |
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#include <linux/cred.h> |
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#include <linux/err.h> |
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#include <linux/slab.h> |
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#include <linux/uidgid.h> |
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#include <linux/verification.h> |
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#include <keys/asymmetric-type.h> |
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#include <keys/system_keyring.h> |
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#include <crypto/pkcs7.h> |
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#include "common.h" |
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static struct key *builtin_trusted_keys; |
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#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING |
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static struct key *secondary_trusted_keys; |
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#endif |
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#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING |
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static struct key *platform_trusted_keys; |
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#endif |
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extern __initconst const u8 system_certificate_list[]; |
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extern __initconst const unsigned long system_certificate_list_size; |
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extern __initconst const unsigned long module_cert_size; |
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/** |
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* restrict_link_to_builtin_trusted - Restrict keyring addition by built in CA |
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* |
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* Restrict the addition of keys into a keyring based on the key-to-be-added |
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* being vouched for by a key in the built in system keyring. |
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*/ |
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int restrict_link_by_builtin_trusted(struct key *dest_keyring, |
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const struct key_type *type, |
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const union key_payload *payload, |
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struct key *restriction_key) |
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{ |
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return restrict_link_by_signature(dest_keyring, type, payload, |
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builtin_trusted_keys); |
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} |
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#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING |
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/** |
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* restrict_link_by_builtin_and_secondary_trusted - Restrict keyring |
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* addition by both builtin and secondary keyrings |
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* |
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* Restrict the addition of keys into a keyring based on the key-to-be-added |
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* being vouched for by a key in either the built-in or the secondary system |
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* keyrings. |
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*/ |
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int restrict_link_by_builtin_and_secondary_trusted( |
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struct key *dest_keyring, |
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const struct key_type *type, |
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const union key_payload *payload, |
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struct key *restrict_key) |
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{ |
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/* If we have a secondary trusted keyring, then that contains a link |
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* through to the builtin keyring and the search will follow that link. |
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*/ |
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if (type == &key_type_keyring && |
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dest_keyring == secondary_trusted_keys && |
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payload == &builtin_trusted_keys->payload) |
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/* Allow the builtin keyring to be added to the secondary */ |
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return 0; |
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return restrict_link_by_signature(dest_keyring, type, payload, |
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secondary_trusted_keys); |
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} |
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/** |
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* Allocate a struct key_restriction for the "builtin and secondary trust" |
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* keyring. Only for use in system_trusted_keyring_init(). |
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*/ |
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static __init struct key_restriction *get_builtin_and_secondary_restriction(void) |
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{ |
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struct key_restriction *restriction; |
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restriction = kzalloc(sizeof(struct key_restriction), GFP_KERNEL); |
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if (!restriction) |
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panic("Can't allocate secondary trusted keyring restriction\n"); |
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restriction->check = restrict_link_by_builtin_and_secondary_trusted; |
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return restriction; |
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} |
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#endif |
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/* |
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* Create the trusted keyrings |
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*/ |
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static __init int system_trusted_keyring_init(void) |
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{ |
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pr_notice("Initialise system trusted keyrings\n"); |
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builtin_trusted_keys = |
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keyring_alloc(".builtin_trusted_keys", |
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GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), |
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((KEY_POS_ALL & ~KEY_POS_SETATTR) | |
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KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH), |
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KEY_ALLOC_NOT_IN_QUOTA, |
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NULL, NULL); |
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if (IS_ERR(builtin_trusted_keys)) |
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panic("Can't allocate builtin trusted keyring\n"); |
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#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING |
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secondary_trusted_keys = |
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keyring_alloc(".secondary_trusted_keys", |
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GLOBAL_ROOT_UID, GLOBAL_ROOT_GID, current_cred(), |
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((KEY_POS_ALL & ~KEY_POS_SETATTR) | |
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KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH | |
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KEY_USR_WRITE), |
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KEY_ALLOC_NOT_IN_QUOTA, |
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get_builtin_and_secondary_restriction(), |
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NULL); |
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if (IS_ERR(secondary_trusted_keys)) |
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panic("Can't allocate secondary trusted keyring\n"); |
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if (key_link(secondary_trusted_keys, builtin_trusted_keys) < 0) |
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panic("Can't link trusted keyrings\n"); |
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#endif |
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return 0; |
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} |
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/* |
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* Must be initialised before we try and load the keys into the keyring. |
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*/ |
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device_initcall(system_trusted_keyring_init); |
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__init int load_module_cert(struct key *keyring) |
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{ |
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if (!IS_ENABLED(CONFIG_IMA_APPRAISE_MODSIG)) |
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return 0; |
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pr_notice("Loading compiled-in module X.509 certificates\n"); |
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return load_certificate_list(system_certificate_list, module_cert_size, keyring); |
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} |
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/* |
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* Load the compiled-in list of X.509 certificates. |
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*/ |
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static __init int load_system_certificate_list(void) |
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{ |
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const u8 *p; |
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unsigned long size; |
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pr_notice("Loading compiled-in X.509 certificates\n"); |
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#ifdef CONFIG_MODULE_SIG |
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p = system_certificate_list; |
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size = system_certificate_list_size; |
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#else |
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p = system_certificate_list + module_cert_size; |
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size = system_certificate_list_size - module_cert_size; |
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#endif |
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return load_certificate_list(p, size, builtin_trusted_keys); |
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} |
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late_initcall(load_system_certificate_list); |
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#ifdef CONFIG_SYSTEM_DATA_VERIFICATION |
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/** |
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* verify_pkcs7_message_sig - Verify a PKCS#7-based signature on system data. |
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* @data: The data to be verified (NULL if expecting internal data). |
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* @len: Size of @data. |
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* @pkcs7: The PKCS#7 message that is the signature. |
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* @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only, |
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* (void *)1UL for all trusted keys). |
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* @usage: The use to which the key is being put. |
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* @view_content: Callback to gain access to content. |
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* @ctx: Context for callback. |
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*/ |
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int verify_pkcs7_message_sig(const void *data, size_t len, |
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struct pkcs7_message *pkcs7, |
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struct key *trusted_keys, |
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enum key_being_used_for usage, |
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int (*view_content)(void *ctx, |
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const void *data, size_t len, |
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size_t asn1hdrlen), |
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void *ctx) |
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{ |
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int ret; |
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/* The data should be detached - so we need to supply it. */ |
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if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) { |
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pr_err("PKCS#7 signature with non-detached data\n"); |
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ret = -EBADMSG; |
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goto error; |
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} |
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ret = pkcs7_verify(pkcs7, usage); |
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if (ret < 0) |
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goto error; |
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if (!trusted_keys) { |
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trusted_keys = builtin_trusted_keys; |
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} else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) { |
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#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING |
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trusted_keys = secondary_trusted_keys; |
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#else |
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trusted_keys = builtin_trusted_keys; |
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#endif |
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} else if (trusted_keys == VERIFY_USE_PLATFORM_KEYRING) { |
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#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING |
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trusted_keys = platform_trusted_keys; |
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#else |
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trusted_keys = NULL; |
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#endif |
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if (!trusted_keys) { |
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ret = -ENOKEY; |
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pr_devel("PKCS#7 platform keyring is not available\n"); |
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goto error; |
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} |
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ret = is_key_on_revocation_list(pkcs7); |
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if (ret != -ENOKEY) { |
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pr_devel("PKCS#7 platform key is on revocation list\n"); |
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goto error; |
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} |
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} |
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ret = pkcs7_validate_trust(pkcs7, trusted_keys); |
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if (ret < 0) { |
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if (ret == -ENOKEY) |
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pr_devel("PKCS#7 signature not signed with a trusted key\n"); |
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goto error; |
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} |
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if (view_content) { |
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size_t asn1hdrlen; |
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ret = pkcs7_get_content_data(pkcs7, &data, &len, &asn1hdrlen); |
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if (ret < 0) { |
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if (ret == -ENODATA) |
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pr_devel("PKCS#7 message does not contain data\n"); |
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goto error; |
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} |
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ret = view_content(ctx, data, len, asn1hdrlen); |
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} |
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error: |
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pr_devel("<==%s() = %d\n", __func__, ret); |
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return ret; |
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} |
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/** |
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* verify_pkcs7_signature - Verify a PKCS#7-based signature on system data. |
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* @data: The data to be verified (NULL if expecting internal data). |
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* @len: Size of @data. |
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* @raw_pkcs7: The PKCS#7 message that is the signature. |
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* @pkcs7_len: The size of @raw_pkcs7. |
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* @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only, |
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* (void *)1UL for all trusted keys). |
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* @usage: The use to which the key is being put. |
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* @view_content: Callback to gain access to content. |
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* @ctx: Context for callback. |
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*/ |
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int verify_pkcs7_signature(const void *data, size_t len, |
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const void *raw_pkcs7, size_t pkcs7_len, |
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struct key *trusted_keys, |
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enum key_being_used_for usage, |
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int (*view_content)(void *ctx, |
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const void *data, size_t len, |
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size_t asn1hdrlen), |
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void *ctx) |
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{ |
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struct pkcs7_message *pkcs7; |
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int ret; |
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pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len); |
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if (IS_ERR(pkcs7)) |
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return PTR_ERR(pkcs7); |
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ret = verify_pkcs7_message_sig(data, len, pkcs7, trusted_keys, usage, |
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view_content, ctx); |
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pkcs7_free_message(pkcs7); |
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pr_devel("<==%s() = %d\n", __func__, ret); |
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return ret; |
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} |
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EXPORT_SYMBOL_GPL(verify_pkcs7_signature); |
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#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */ |
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#ifdef CONFIG_INTEGRITY_PLATFORM_KEYRING |
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void __init set_platform_trusted_keys(struct key *keyring) |
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{ |
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platform_trusted_keys = keyring; |
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} |
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#endif
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