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243 lines
5.7 KiB
243 lines
5.7 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* System hash blacklist. |
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* |
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* Copyright (C) 2016 Red Hat, Inc. All Rights Reserved. |
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* Written by David Howells ([email protected]) |
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*/ |
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#define pr_fmt(fmt) "blacklist: "fmt |
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#include <linux/module.h> |
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#include <linux/slab.h> |
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#include <linux/key.h> |
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#include <linux/key-type.h> |
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#include <linux/sched.h> |
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#include <linux/ctype.h> |
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#include <linux/err.h> |
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#include <linux/seq_file.h> |
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#include <linux/uidgid.h> |
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#include <keys/system_keyring.h> |
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#include "blacklist.h" |
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#include "common.h" |
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static struct key *blacklist_keyring; |
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#ifdef CONFIG_SYSTEM_REVOCATION_LIST |
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extern __initconst const u8 revocation_certificate_list[]; |
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extern __initconst const unsigned long revocation_certificate_list_size; |
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#endif |
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/* |
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* The description must be a type prefix, a colon and then an even number of |
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* hex digits. The hash is kept in the description. |
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*/ |
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static int blacklist_vet_description(const char *desc) |
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{ |
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int n = 0; |
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if (*desc == ':') |
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return -EINVAL; |
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for (; *desc; desc++) |
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if (*desc == ':') |
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goto found_colon; |
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return -EINVAL; |
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found_colon: |
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desc++; |
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for (; *desc; desc++) { |
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if (!isxdigit(*desc) || isupper(*desc)) |
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return -EINVAL; |
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n++; |
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} |
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if (n == 0 || n & 1) |
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return -EINVAL; |
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return 0; |
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} |
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/* |
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* The hash to be blacklisted is expected to be in the description. There will |
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* be no payload. |
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*/ |
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static int blacklist_preparse(struct key_preparsed_payload *prep) |
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{ |
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if (prep->datalen > 0) |
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return -EINVAL; |
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return 0; |
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} |
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static void blacklist_free_preparse(struct key_preparsed_payload *prep) |
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{ |
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} |
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static void blacklist_describe(const struct key *key, struct seq_file *m) |
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{ |
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seq_puts(m, key->description); |
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} |
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static struct key_type key_type_blacklist = { |
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.name = "blacklist", |
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.vet_description = blacklist_vet_description, |
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.preparse = blacklist_preparse, |
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.free_preparse = blacklist_free_preparse, |
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.instantiate = generic_key_instantiate, |
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.describe = blacklist_describe, |
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}; |
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/** |
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* mark_hash_blacklisted - Add a hash to the system blacklist |
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* @hash: The hash as a hex string with a type prefix (eg. "tbs:23aa429783") |
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*/ |
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int mark_hash_blacklisted(const char *hash) |
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{ |
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key_ref_t key; |
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key = key_create_or_update(make_key_ref(blacklist_keyring, true), |
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"blacklist", |
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hash, |
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NULL, |
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0, |
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((KEY_POS_ALL & ~KEY_POS_SETATTR) | |
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KEY_USR_VIEW), |
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KEY_ALLOC_NOT_IN_QUOTA | |
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KEY_ALLOC_BUILT_IN); |
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if (IS_ERR(key)) { |
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pr_err("Problem blacklisting hash (%ld)\n", PTR_ERR(key)); |
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return PTR_ERR(key); |
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} |
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return 0; |
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} |
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/** |
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* is_hash_blacklisted - Determine if a hash is blacklisted |
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* @hash: The hash to be checked as a binary blob |
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* @hash_len: The length of the binary hash |
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* @type: Type of hash |
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*/ |
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int is_hash_blacklisted(const u8 *hash, size_t hash_len, const char *type) |
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{ |
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key_ref_t kref; |
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size_t type_len = strlen(type); |
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char *buffer, *p; |
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int ret = 0; |
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buffer = kmalloc(type_len + 1 + hash_len * 2 + 1, GFP_KERNEL); |
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if (!buffer) |
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return -ENOMEM; |
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p = memcpy(buffer, type, type_len); |
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p += type_len; |
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*p++ = ':'; |
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bin2hex(p, hash, hash_len); |
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p += hash_len * 2; |
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*p = 0; |
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kref = keyring_search(make_key_ref(blacklist_keyring, true), |
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&key_type_blacklist, buffer, false); |
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if (!IS_ERR(kref)) { |
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key_ref_put(kref); |
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ret = -EKEYREJECTED; |
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} |
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kfree(buffer); |
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return ret; |
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} |
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EXPORT_SYMBOL_GPL(is_hash_blacklisted); |
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int is_binary_blacklisted(const u8 *hash, size_t hash_len) |
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{ |
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if (is_hash_blacklisted(hash, hash_len, "bin") == -EKEYREJECTED) |
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return -EPERM; |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(is_binary_blacklisted); |
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#ifdef CONFIG_SYSTEM_REVOCATION_LIST |
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/** |
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* add_key_to_revocation_list - Add a revocation certificate to the blacklist |
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* @data: The data blob containing the certificate |
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* @size: The size of data blob |
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*/ |
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int add_key_to_revocation_list(const char *data, size_t size) |
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{ |
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key_ref_t key; |
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key = key_create_or_update(make_key_ref(blacklist_keyring, true), |
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"asymmetric", |
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NULL, |
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data, |
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size, |
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((KEY_POS_ALL & ~KEY_POS_SETATTR) | KEY_USR_VIEW), |
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KEY_ALLOC_NOT_IN_QUOTA | KEY_ALLOC_BUILT_IN); |
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if (IS_ERR(key)) { |
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pr_err("Problem with revocation key (%ld)\n", PTR_ERR(key)); |
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return PTR_ERR(key); |
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} |
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return 0; |
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} |
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/** |
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* is_key_on_revocation_list - Determine if the key for a PKCS#7 message is revoked |
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* @pkcs7: The PKCS#7 message to check |
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*/ |
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int is_key_on_revocation_list(struct pkcs7_message *pkcs7) |
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{ |
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int ret; |
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ret = pkcs7_validate_trust(pkcs7, blacklist_keyring); |
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if (ret == 0) |
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return -EKEYREJECTED; |
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return -ENOKEY; |
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} |
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#endif |
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/* |
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* Initialise the blacklist |
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*/ |
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static int __init blacklist_init(void) |
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{ |
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const char *const *bl; |
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if (register_key_type(&key_type_blacklist) < 0) |
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panic("Can't allocate system blacklist key type\n"); |
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blacklist_keyring = |
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keyring_alloc(".blacklist", |
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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 | |
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KEY_USR_SEARCH, |
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KEY_ALLOC_NOT_IN_QUOTA | |
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KEY_ALLOC_SET_KEEP, |
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NULL, NULL); |
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if (IS_ERR(blacklist_keyring)) |
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panic("Can't allocate system blacklist keyring\n"); |
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for (bl = blacklist_hashes; *bl; bl++) |
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if (mark_hash_blacklisted(*bl) < 0) |
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pr_err("- blacklisting failed\n"); |
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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(blacklist_init); |
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#ifdef CONFIG_SYSTEM_REVOCATION_LIST |
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/* |
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* Load the compiled-in list of revocation X.509 certificates. |
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*/ |
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static __init int load_revocation_certificate_list(void) |
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{ |
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if (revocation_certificate_list_size) |
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pr_notice("Loading compiled-in revocation X.509 certificates\n"); |
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return load_certificate_list(revocation_certificate_list, revocation_certificate_list_size, |
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blacklist_keyring); |
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} |
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late_initcall(load_revocation_certificate_list); |
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#endif
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