mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 10:49:33 +00:00
![David Howells](/assets/img/avatar_default.png)
The keyring expansion patches introduces a new search method by which key_search() attempts to walk directly to the key that has exactly the same description as the requested one. However, this causes inexact matching of asymmetric keys to fail. The solution to this is to select iterative rather than direct search as the default search type for asymmetric keys. As an example, the kernel might have a key like this: Magrathea: Glacier signing key: 6a2a0f82bad7e396665f465e4e3e1f9bd24b1226 and: keyctl search <keyring-ID> asymmetric id:d24b1226 should find the key, despite that not being its exact description. Signed-off-by: David Howells <dhowells@redhat.com>
275 lines
6.7 KiB
C
275 lines
6.7 KiB
C
/* Asymmetric public-key cryptography key type
|
|
*
|
|
* See Documentation/security/asymmetric-keys.txt
|
|
*
|
|
* 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 <keys/asymmetric-subtype.h>
|
|
#include <keys/asymmetric-parser.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/module.h>
|
|
#include <linux/slab.h>
|
|
#include "asymmetric_keys.h"
|
|
|
|
MODULE_LICENSE("GPL");
|
|
|
|
static LIST_HEAD(asymmetric_key_parsers);
|
|
static DECLARE_RWSEM(asymmetric_key_parsers_sem);
|
|
|
|
/*
|
|
* Match asymmetric keys on (part of) their name
|
|
* We have some shorthand methods for matching keys. We allow:
|
|
*
|
|
* "<desc>" - request a key by description
|
|
* "id:<id>" - request a key matching the ID
|
|
* "<subtype>:<id>" - request a key of a subtype
|
|
*/
|
|
static int asymmetric_key_match(const struct key *key, const void *description)
|
|
{
|
|
const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
|
|
const char *spec = description;
|
|
const char *id, *kid;
|
|
ptrdiff_t speclen;
|
|
size_t idlen, kidlen;
|
|
|
|
if (!subtype || !spec || !*spec)
|
|
return 0;
|
|
|
|
/* See if the full key description matches as is */
|
|
if (key->description && strcmp(key->description, description) == 0)
|
|
return 1;
|
|
|
|
/* All tests from here on break the criterion description into a
|
|
* specifier, a colon and then an identifier.
|
|
*/
|
|
id = strchr(spec, ':');
|
|
if (!id)
|
|
return 0;
|
|
|
|
speclen = id - spec;
|
|
id++;
|
|
|
|
/* Anything after here requires a partial match on the ID string */
|
|
kid = asymmetric_key_id(key);
|
|
if (!kid)
|
|
return 0;
|
|
|
|
idlen = strlen(id);
|
|
kidlen = strlen(kid);
|
|
if (idlen > kidlen)
|
|
return 0;
|
|
|
|
kid += kidlen - idlen;
|
|
if (strcasecmp(id, kid) != 0)
|
|
return 0;
|
|
|
|
if (speclen == 2 &&
|
|
memcmp(spec, "id", 2) == 0)
|
|
return 1;
|
|
|
|
if (speclen == subtype->name_len &&
|
|
memcmp(spec, subtype->name, speclen) == 0)
|
|
return 1;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Describe the asymmetric key
|
|
*/
|
|
static void asymmetric_key_describe(const struct key *key, struct seq_file *m)
|
|
{
|
|
const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
|
|
const char *kid = asymmetric_key_id(key);
|
|
size_t n;
|
|
|
|
seq_puts(m, key->description);
|
|
|
|
if (subtype) {
|
|
seq_puts(m, ": ");
|
|
subtype->describe(key, m);
|
|
|
|
if (kid) {
|
|
seq_putc(m, ' ');
|
|
n = strlen(kid);
|
|
if (n <= 8)
|
|
seq_puts(m, kid);
|
|
else
|
|
seq_puts(m, kid + n - 8);
|
|
}
|
|
|
|
seq_puts(m, " [");
|
|
/* put something here to indicate the key's capabilities */
|
|
seq_putc(m, ']');
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Preparse a asymmetric payload to get format the contents appropriately for the
|
|
* internal payload to cut down on the number of scans of the data performed.
|
|
*
|
|
* We also generate a proposed description from the contents of the key that
|
|
* can be used to name the key if the user doesn't want to provide one.
|
|
*/
|
|
static int asymmetric_key_preparse(struct key_preparsed_payload *prep)
|
|
{
|
|
struct asymmetric_key_parser *parser;
|
|
int ret;
|
|
|
|
pr_devel("==>%s()\n", __func__);
|
|
|
|
if (prep->datalen == 0)
|
|
return -EINVAL;
|
|
|
|
down_read(&asymmetric_key_parsers_sem);
|
|
|
|
ret = -EBADMSG;
|
|
list_for_each_entry(parser, &asymmetric_key_parsers, link) {
|
|
pr_debug("Trying parser '%s'\n", parser->name);
|
|
|
|
ret = parser->parse(prep);
|
|
if (ret != -EBADMSG) {
|
|
pr_debug("Parser recognised the format (ret %d)\n",
|
|
ret);
|
|
break;
|
|
}
|
|
}
|
|
|
|
up_read(&asymmetric_key_parsers_sem);
|
|
pr_devel("<==%s() = %d\n", __func__, ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Clean up the preparse data
|
|
*/
|
|
static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep)
|
|
{
|
|
struct asymmetric_key_subtype *subtype = prep->type_data[0];
|
|
|
|
pr_devel("==>%s()\n", __func__);
|
|
|
|
if (subtype) {
|
|
subtype->destroy(prep->payload);
|
|
module_put(subtype->owner);
|
|
}
|
|
kfree(prep->type_data[1]);
|
|
kfree(prep->description);
|
|
}
|
|
|
|
/*
|
|
* Instantiate a asymmetric_key defined key. The key was preparsed, so we just
|
|
* have to transfer the data here.
|
|
*/
|
|
static int asymmetric_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
|
|
{
|
|
int ret;
|
|
|
|
pr_devel("==>%s()\n", __func__);
|
|
|
|
ret = key_payload_reserve(key, prep->quotalen);
|
|
if (ret == 0) {
|
|
key->type_data.p[0] = prep->type_data[0];
|
|
key->type_data.p[1] = prep->type_data[1];
|
|
key->payload.data = prep->payload;
|
|
prep->type_data[0] = NULL;
|
|
prep->type_data[1] = NULL;
|
|
prep->payload = NULL;
|
|
}
|
|
pr_devel("<==%s() = %d\n", __func__, ret);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* dispose of the data dangling from the corpse of a asymmetric key
|
|
*/
|
|
static void asymmetric_key_destroy(struct key *key)
|
|
{
|
|
struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
|
|
if (subtype) {
|
|
subtype->destroy(key->payload.data);
|
|
module_put(subtype->owner);
|
|
key->type_data.p[0] = NULL;
|
|
}
|
|
kfree(key->type_data.p[1]);
|
|
key->type_data.p[1] = NULL;
|
|
}
|
|
|
|
struct key_type key_type_asymmetric = {
|
|
.name = "asymmetric",
|
|
.preparse = asymmetric_key_preparse,
|
|
.free_preparse = asymmetric_key_free_preparse,
|
|
.instantiate = asymmetric_key_instantiate,
|
|
.match = asymmetric_key_match,
|
|
.destroy = asymmetric_key_destroy,
|
|
.describe = asymmetric_key_describe,
|
|
.def_lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE,
|
|
};
|
|
EXPORT_SYMBOL_GPL(key_type_asymmetric);
|
|
|
|
/**
|
|
* register_asymmetric_key_parser - Register a asymmetric key blob parser
|
|
* @parser: The parser to register
|
|
*/
|
|
int register_asymmetric_key_parser(struct asymmetric_key_parser *parser)
|
|
{
|
|
struct asymmetric_key_parser *cursor;
|
|
int ret;
|
|
|
|
down_write(&asymmetric_key_parsers_sem);
|
|
|
|
list_for_each_entry(cursor, &asymmetric_key_parsers, link) {
|
|
if (strcmp(cursor->name, parser->name) == 0) {
|
|
pr_err("Asymmetric key parser '%s' already registered\n",
|
|
parser->name);
|
|
ret = -EEXIST;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
list_add_tail(&parser->link, &asymmetric_key_parsers);
|
|
|
|
pr_notice("Asymmetric key parser '%s' registered\n", parser->name);
|
|
ret = 0;
|
|
|
|
out:
|
|
up_write(&asymmetric_key_parsers_sem);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(register_asymmetric_key_parser);
|
|
|
|
/**
|
|
* unregister_asymmetric_key_parser - Unregister a asymmetric key blob parser
|
|
* @parser: The parser to unregister
|
|
*/
|
|
void unregister_asymmetric_key_parser(struct asymmetric_key_parser *parser)
|
|
{
|
|
down_write(&asymmetric_key_parsers_sem);
|
|
list_del(&parser->link);
|
|
up_write(&asymmetric_key_parsers_sem);
|
|
|
|
pr_notice("Asymmetric key parser '%s' unregistered\n", parser->name);
|
|
}
|
|
EXPORT_SYMBOL_GPL(unregister_asymmetric_key_parser);
|
|
|
|
/*
|
|
* Module stuff
|
|
*/
|
|
static int __init asymmetric_key_init(void)
|
|
{
|
|
return register_key_type(&key_type_asymmetric);
|
|
}
|
|
|
|
static void __exit asymmetric_key_cleanup(void)
|
|
{
|
|
unregister_key_type(&key_type_asymmetric);
|
|
}
|
|
|
|
module_init(asymmetric_key_init);
|
|
module_exit(asymmetric_key_cleanup);
|