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- /* 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 */
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