cfc411e7ff
Move certificate handling out of the kernel/ directory and into a certs/ directory to get all the weird stuff in one place and move the generated signing keys into this directory. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: David Woodhouse <David.Woodhouse@intel.com>
157 lines
4 KiB
C
157 lines
4 KiB
C
/* 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 (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, or (at your option) any later version.
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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 <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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struct key *system_trusted_keyring;
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EXPORT_SYMBOL_GPL(system_trusted_keyring);
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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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/*
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* Load the compiled-in keys
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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 keyring\n");
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system_trusted_keyring =
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keyring_alloc(".system_keyring",
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KUIDT_INIT(0), KGIDT_INIT(0), 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, NULL);
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if (IS_ERR(system_trusted_keyring))
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panic("Can't allocate system trusted keyring\n");
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set_bit(KEY_FLAG_TRUSTED_ONLY, &system_trusted_keyring->flags);
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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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/*
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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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key_ref_t key;
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const u8 *p, *end;
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size_t plen;
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pr_notice("Loading compiled-in X.509 certificates\n");
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p = system_certificate_list;
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end = p + system_certificate_list_size;
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while (p < end) {
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/* Each cert begins with an ASN.1 SEQUENCE tag and must be more
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* than 256 bytes in size.
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*/
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if (end - p < 4)
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goto dodgy_cert;
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if (p[0] != 0x30 &&
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p[1] != 0x82)
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goto dodgy_cert;
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plen = (p[2] << 8) | p[3];
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plen += 4;
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if (plen > end - p)
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goto dodgy_cert;
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key = key_create_or_update(make_key_ref(system_trusted_keyring, 1),
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"asymmetric",
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NULL,
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p,
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plen,
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((KEY_POS_ALL & ~KEY_POS_SETATTR) |
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KEY_USR_VIEW | KEY_USR_READ),
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KEY_ALLOC_NOT_IN_QUOTA |
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KEY_ALLOC_TRUSTED);
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if (IS_ERR(key)) {
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pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
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PTR_ERR(key));
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} else {
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set_bit(KEY_FLAG_BUILTIN, &key_ref_to_ptr(key)->flags);
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pr_notice("Loaded X.509 cert '%s'\n",
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key_ref_to_ptr(key)->description);
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key_ref_put(key);
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}
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p += plen;
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}
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return 0;
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dodgy_cert:
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pr_err("Problem parsing in-kernel X.509 certificate list\n");
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return 0;
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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 a PKCS#7-based signature on system data.
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* @data: The data to be verified.
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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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* @usage: The use to which the key is being put.
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*/
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int system_verify_data(const void *data, unsigned long len,
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const void *raw_pkcs7, size_t pkcs7_len,
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enum key_being_used_for usage)
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{
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struct pkcs7_message *pkcs7;
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bool trusted;
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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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/* The data should be detached - so we need to supply it. */
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if (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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ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
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if (ret < 0)
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goto error;
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if (!trusted) {
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pr_err("PKCS#7 signature not signed with a trusted key\n");
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ret = -ENOKEY;
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}
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error:
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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(system_verify_data);
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#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
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