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/* 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 <crypto/public_key.h>
#include <linux/seq_file.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/ctype.h>
#include "asymmetric_keys.h"
MODULE_LICENSE("GPL");
const char *const key_being_used_for[NR__KEY_BEING_USED_FOR] = {
[VERIFYING_MODULE_SIGNATURE] = "mod sig",
[VERIFYING_FIRMWARE_SIGNATURE] = "firmware sig",
[VERIFYING_KEXEC_PE_SIGNATURE] = "kexec PE sig",
[VERIFYING_KEY_SIGNATURE] = "key sig",
[VERIFYING_KEY_SELF_SIGNATURE] = "key self sig",
[VERIFYING_UNSPECIFIED_SIGNATURE] = "unspec sig",
};
EXPORT_SYMBOL_GPL(key_being_used_for);
static LIST_HEAD(asymmetric_key_parsers);
static DECLARE_RWSEM(asymmetric_key_parsers_sem);
/**
* asymmetric_key_generate_id: Construct an asymmetric key ID
* @val_1: First binary blob
* @len_1: Length of first binary blob
* @val_2: Second binary blob
* @len_2: Length of second binary blob
*
* Construct an asymmetric key ID from a pair of binary blobs.
*/
struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
size_t len_1,
const void *val_2,
size_t len_2)
{
struct asymmetric_key_id *kid;
kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2,
GFP_KERNEL);
if (!kid)
return ERR_PTR(-ENOMEM);
kid->len = len_1 + len_2;
memcpy(kid->data, val_1, len_1);
memcpy(kid->data + len_1, val_2, len_2);
return kid;
}
EXPORT_SYMBOL_GPL(asymmetric_key_generate_id);
/**
* asymmetric_key_id_same - Return true if two asymmetric keys IDs are the same.
* @kid_1, @kid_2: The key IDs to compare
*/
bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1,
const struct asymmetric_key_id *kid2)
{
if (!kid1 || !kid2)
return false;
if (kid1->len != kid2->len)
return false;
return memcmp(kid1->data, kid2->data, kid1->len) == 0;
}
EXPORT_SYMBOL_GPL(asymmetric_key_id_same);
/**
* asymmetric_key_id_partial - Return true if two asymmetric keys IDs
* partially match
* @kid_1, @kid_2: The key IDs to compare
*/
bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1,
const struct asymmetric_key_id *kid2)
{
if (!kid1 || !kid2)
return false;
if (kid1->len < kid2->len)
return false;
return memcmp(kid1->data + (kid1->len - kid2->len),
kid2->data, kid2->len) == 0;
}
EXPORT_SYMBOL_GPL(asymmetric_key_id_partial);
/**
* asymmetric_match_key_ids - Search asymmetric key IDs
* @kids: The list of key IDs to check
* @match_id: The key ID we're looking for
* @match: The match function to use
*/
static bool asymmetric_match_key_ids(
const struct asymmetric_key_ids *kids,
const struct asymmetric_key_id *match_id,
bool (*match)(const struct asymmetric_key_id *kid1,
const struct asymmetric_key_id *kid2))
{
int i;
if (!kids || !match_id)
return false;
for (i = 0; i < ARRAY_SIZE(kids->id); i++)
if (match(kids->id[i], match_id))
return true;
return false;
}
/* helper function can be called directly with pre-allocated memory */
inline int __asymmetric_key_hex_to_key_id(const char *id,
struct asymmetric_key_id *match_id,
size_t hexlen)
{
match_id->len = hexlen;
return hex2bin(match_id->data, id, hexlen);
}
/**
* asymmetric_key_hex_to_key_id - Convert a hex string into a key ID.
* @id: The ID as a hex string.
*/
struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id)
{
struct asymmetric_key_id *match_id;
size_t asciihexlen;
int ret;
if (!*id)
return ERR_PTR(-EINVAL);
asciihexlen = strlen(id);
if (asciihexlen & 1)
return ERR_PTR(-EINVAL);
match_id = kmalloc(sizeof(struct asymmetric_key_id) + asciihexlen / 2,
GFP_KERNEL);
if (!match_id)
return ERR_PTR(-ENOMEM);
ret = __asymmetric_key_hex_to_key_id(id, match_id, asciihexlen / 2);
if (ret < 0) {
kfree(match_id);
return ERR_PTR(-EINVAL);
}
return match_id;
}
/*
* Match asymmetric keys by an exact match on an ID.
*/
static bool asymmetric_key_cmp(const struct key *key,
const struct key_match_data *match_data)
{
const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
const struct asymmetric_key_id *match_id = match_data->preparsed;
return asymmetric_match_key_ids(kids, match_id,
asymmetric_key_id_same);
}
/*
* Match asymmetric keys by a partial match on an IDs.
*/
static bool asymmetric_key_cmp_partial(const struct key *key,
const struct key_match_data *match_data)
{
const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
const struct asymmetric_key_id *match_id = match_data->preparsed;
return asymmetric_match_key_ids(kids, match_id,
asymmetric_key_id_partial);
}
/*
* Preparse the match criterion. If we don't set lookup_type and cmp,
* the default will be an exact match on the key description.
*
* There are some specifiers for matching key IDs rather than by the key
* description:
*
* "id:<id>" - find a key by partial match on any available ID
* "ex:<id>" - find a key by exact match on any available ID
*
* These have to be searched by iteration rather than by direct lookup because
* the key is hashed according to its description.
*/
static int asymmetric_key_match_preparse(struct key_match_data *match_data)
{
struct asymmetric_key_id *match_id;
const char *spec = match_data->raw_data;
const char *id;
bool (*cmp)(const struct key *, const struct key_match_data *) =
asymmetric_key_cmp;
if (!spec || !*spec)
return -EINVAL;
if (spec[0] == 'i' &&
spec[1] == 'd' &&
spec[2] == ':') {
id = spec + 3;
cmp = asymmetric_key_cmp_partial;
} else if (spec[0] == 'e' &&
spec[1] == 'x' &&
spec[2] == ':') {
id = spec + 3;
} else {
goto default_match;
}
match_id = asymmetric_key_hex_to_key_id(id);
if (IS_ERR(match_id))
return PTR_ERR(match_id);
match_data->preparsed = match_id;
match_data->cmp = cmp;
match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE;
return 0;
default_match:
return 0;
}
/*
* Free the preparsed the match criterion.
*/
static void asymmetric_key_match_free(struct key_match_data *match_data)
{
kfree(match_data->preparsed);
}
/*
* 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 struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
const struct asymmetric_key_id *kid;
const unsigned char *p;
int n;
seq_puts(m, key->description);
if (subtype) {
seq_puts(m, ": ");
subtype->describe(key, m);
if (kids && kids->id[1]) {
kid = kids->id[1];
seq_putc(m, ' ');
n = kid->len;
p = kid->data;
if (n > 4) {
p +=
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