linux/certs/blacklist.c
Thomas Gleixner b4d0d230cc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 114 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-24 17:27:11 +02:00

171 lines
3.8 KiB
C

// 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"
static struct key *blacklist_keyring;
/*
* 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);
if (!IS_ERR(kref)) {
key_ref_put(kref);
ret = -EKEYREJECTED;
}
kfree(buffer);
return ret;
}
EXPORT_SYMBOL_GPL(is_hash_blacklisted);
/*
* 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_FLAG_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);