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