// SPDX-License-Identifier: GPL-2.0-or-later
|
/* Asymmetric public-key cryptography key type
|
*
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* See Documentation/crypto/asymmetric-keys.rst
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*
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* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*/
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#include <keys/asymmetric-subtype.h>
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#include <keys/asymmetric-parser.h>
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#include <crypto/public_key.h>
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#include <linux/seq_file.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/ctype.h>
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#include <keys/system_keyring.h>
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#include <keys/user-type.h>
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#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",
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[VERIFYING_KEY_SIGNATURE] = "key sig",
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[VERIFYING_KEY_SELF_SIGNATURE] = "key self sig",
|
[VERIFYING_UNSPECIFIED_SIGNATURE] = "unspec sig",
|
};
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EXPORT_SYMBOL_GPL(key_being_used_for);
|
|
static LIST_HEAD(asymmetric_key_parsers);
|
static DECLARE_RWSEM(asymmetric_key_parsers_sem);
|
|
/**
|
* find_asymmetric_key - Find a key by ID.
|
* @keyring: The keys to search.
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* @id_0: The first ID to look for or NULL.
|
* @id_1: The second ID to look for or NULL.
|
* @partial: Use partial match if true, exact if false.
|
*
|
* Find a key in the given keyring by identifier. The preferred identifier is
|
* the id_0 and the fallback identifier is the id_1. If both are given, the
|
* lookup is by the former, but the latter must also match.
|
*/
|
struct key *find_asymmetric_key(struct key *keyring,
|
const struct asymmetric_key_id *id_0,
|
const struct asymmetric_key_id *id_1,
|
bool partial)
|
{
|
struct key *key;
|
key_ref_t ref;
|
const char *lookup;
|
char *req, *p;
|
int len;
|
|
BUG_ON(!id_0 && !id_1);
|
|
if (id_0) {
|
lookup = id_0->data;
|
len = id_0->len;
|
} else {
|
lookup = id_1->data;
|
len = id_1->len;
|
}
|
|
/* Construct an identifier "id:<keyid>". */
|
p = req = kmalloc(2 + 1 + len * 2 + 1, GFP_KERNEL);
|
if (!req)
|
return ERR_PTR(-ENOMEM);
|
|
if (partial) {
|
*p++ = 'i';
|
*p++ = 'd';
|
} else {
|
*p++ = 'e';
|
*p++ = 'x';
|
}
|
*p++ = ':';
|
p = bin2hex(p, lookup, len);
|
*p = 0;
|
|
pr_debug("Look up: \"%s\"\n", req);
|
|
ref = keyring_search(make_key_ref(keyring, 1),
|
&key_type_asymmetric, req, true);
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if (IS_ERR(ref))
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pr_debug("Request for key '%s' err %ld\n", req, PTR_ERR(ref));
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kfree(req);
|
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if (IS_ERR(ref)) {
|
switch (PTR_ERR(ref)) {
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/* Hide some search errors */
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case -EACCES:
|
case -ENOTDIR:
|
case -EAGAIN:
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return ERR_PTR(-ENOKEY);
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default:
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return ERR_CAST(ref);
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}
|
}
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key = key_ref_to_ptr(ref);
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if (id_0 && id_1) {
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const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
|
|
if (!kids->id[1]) {
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pr_debug("First ID matches, but second is missing\n");
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goto reject;
|
}
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if (!asymmetric_key_id_same(id_1, kids->id[1])) {
|
pr_debug("First ID matches, but second does not\n");
|
goto reject;
|
}
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}
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pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key));
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return key;
|
|
reject:
|
key_put(key);
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return ERR_PTR(-EKEYREJECTED);
|
}
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EXPORT_SYMBOL_GPL(find_asymmetric_key);
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/**
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* asymmetric_key_generate_id: Construct an asymmetric key ID
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* @val_1: First binary blob
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* @len_1: Length of first binary blob
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* @val_2: Second binary blob
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* @len_2: Length of second binary blob
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*
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* Construct an asymmetric key ID from a pair of binary blobs.
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*/
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struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
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size_t len_1,
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const void *val_2,
|
size_t len_2)
|
{
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struct asymmetric_key_id *kid;
|
|
kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2,
|
GFP_KERNEL);
|
if (!kid)
|
return ERR_PTR(-ENOMEM);
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kid->len = len_1 + len_2;
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memcpy(kid->data, val_1, len_1);
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memcpy(kid->data + len_1, val_2, len_2);
|
return kid;
|
}
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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;
|
}
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EXPORT_SYMBOL_GPL(asymmetric_key_id_partial);
|
|
/**
|
* asymmetric_match_key_ids - Search asymmetric key IDs
|
* @kids: The list of key IDs to check
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* @match_id: The key ID we're looking for
|
* @match: The match function to use
|
*/
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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);
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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.
|
*/
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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;
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const char *id;
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bool (*cmp)(const struct key *, const struct key_match_data *) =
|
asymmetric_key_cmp;
|
|
if (!spec || !*spec)
|
return -EINVAL;
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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] == ':') {
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id = spec + 3;
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} 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;
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|
default_match:
|
return 0;
|
}
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|
/*
|
* 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 += n - 4;
|
n = 4;
|
}
|
seq_printf(m, "%*phN", n, p);
|
}
|
|
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 key ID list
|
*/
|
static void asymmetric_key_free_kids(struct asymmetric_key_ids *kids)
|
{
|
int i;
|
|
if (kids) {
|
for (i = 0; i < ARRAY_SIZE(kids->id); i++)
|
kfree(kids->id[i]);
|
kfree(kids);
|
}
|
}
|
|
/*
|
* Clean up the preparse data
|
*/
|
static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep)
|
{
|
struct asymmetric_key_subtype *subtype = prep->payload.data[asym_subtype];
|
struct asymmetric_key_ids *kids = prep->payload.data[asym_key_ids];
|
|
pr_devel("==>%s()\n", __func__);
|
|
if (subtype) {
|
subtype->destroy(prep->payload.data[asym_crypto],
|
prep->payload.data[asym_auth]);
|
module_put(subtype->owner);
|
}
|
asymmetric_key_free_kids(kids);
|
kfree(prep->description);
|
}
|
|
/*
|
* 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);
|
struct asymmetric_key_ids *kids = key->payload.data[asym_key_ids];
|
void *data = key->payload.data[asym_crypto];
|
void *auth = key->payload.data[asym_auth];
|
|
key->payload.data[asym_crypto] = NULL;
|
key->payload.data[asym_subtype] = NULL;
|
key->payload.data[asym_key_ids] = NULL;
|
key->payload.data[asym_auth] = NULL;
|
|
if (subtype) {
|
subtype->destroy(data, auth);
|
module_put(subtype->owner);
|
}
|
|
asymmetric_key_free_kids(kids);
|
}
|
|
static struct key_restriction *asymmetric_restriction_alloc(
|
key_restrict_link_func_t check,
|
struct key *key)
|
{
|
struct key_restriction *keyres =
|
kzalloc(sizeof(struct key_restriction), GFP_KERNEL);
|
|
if (!keyres)
|
return ERR_PTR(-ENOMEM);
|
|
keyres->check = check;
|
keyres->key = key;
|
keyres->keytype = &key_type_asymmetric;
|
|
return keyres;
|
}
|
|
/*
|
* look up keyring restrict functions for asymmetric keys
|
*/
|
static struct key_restriction *asymmetric_lookup_restriction(
|
const char *restriction)
|
{
|
char *restrict_method;
|
char *parse_buf;
|
char *next;
|
struct key_restriction *ret = ERR_PTR(-EINVAL);
|
|
if (strcmp("builtin_trusted", restriction) == 0)
|
return asymmetric_restriction_alloc(
|
restrict_link_by_builtin_trusted, NULL);
|
|
if (strcmp("builtin_and_secondary_trusted", restriction) == 0)
|
return asymmetric_restriction_alloc(
|
restrict_link_by_builtin_and_secondary_trusted, NULL);
|
|
parse_buf = kstrndup(restriction, PAGE_SIZE, GFP_KERNEL);
|
if (!parse_buf)
|
return ERR_PTR(-ENOMEM);
|
|
next = parse_buf;
|
restrict_method = strsep(&next, ":");
|
|
if ((strcmp(restrict_method, "key_or_keyring") == 0) && next) {
|
char *key_text;
|
key_serial_t serial;
|
struct key *key;
|
key_restrict_link_func_t link_fn =
|
restrict_link_by_key_or_keyring;
|
bool allow_null_key = false;
|
|
key_text = strsep(&next, ":");
|
|
if (next) {
|
if (strcmp(next, "chain") != 0)
|
goto out;
|
|
link_fn = restrict_link_by_key_or_keyring_chain;
|
allow_null_key = true;
|
}
|
|
if (kstrtos32(key_text, 0, &serial) < 0)
|
goto out;
|
|
if ((serial == 0) && allow_null_key) {
|
key = NULL;
|
} else {
|
key = key_lookup(serial);
|
if (IS_ERR(key)) {
|
ret = ERR_CAST(key);
|
goto out;
|
}
|
}
|
|
ret = asymmetric_restriction_alloc(link_fn, key);
|
if (IS_ERR(ret))
|
key_put(key);
|
}
|
|
out:
|
kfree(parse_buf);
|
return ret;
|
}
|
|
int asymmetric_key_eds_op(struct kernel_pkey_params *params,
|
const void *in, void *out)
|
{
|
const struct asymmetric_key_subtype *subtype;
|
struct key *key = params->key;
|
int ret;
|
|
pr_devel("==>%s()\n", __func__);
|
|
if (key->type != &key_type_asymmetric)
|
return -EINVAL;
|
subtype = asymmetric_key_subtype(key);
|
if (!subtype ||
|
!key->payload.data[0])
|
return -EINVAL;
|
if (!subtype->eds_op)
|
return -ENOTSUPP;
|
|
ret = subtype->eds_op(params, in, out);
|
|
pr_devel("<==%s() = %d\n", __func__, ret);
|
return ret;
|
}
|
|
static int asymmetric_key_verify_signature(struct kernel_pkey_params *params,
|
const void *in, const void *in2)
|
{
|
struct public_key_signature sig = {
|
.s_size = params->in2_len,
|
.digest_size = params->in_len,
|
.encoding = params->encoding,
|
.hash_algo = params->hash_algo,
|
.digest = (void *)in,
|
.s = (void *)in2,
|
};
|
|
return verify_signature(params->key, &sig);
|
}
|
|
struct key_type key_type_asymmetric = {
|
.name = "asymmetric",
|
.preparse = asymmetric_key_preparse,
|
.free_preparse = asymmetric_key_free_preparse,
|
.instantiate = generic_key_instantiate,
|
.match_preparse = asymmetric_key_match_preparse,
|
.match_free = asymmetric_key_match_free,
|
.destroy = asymmetric_key_destroy,
|
.describe = asymmetric_key_describe,
|
.lookup_restriction = asymmetric_lookup_restriction,
|
.asym_query = query_asymmetric_key,
|
.asym_eds_op = asymmetric_key_eds_op,
|
.asym_verify_signature = asymmetric_key_verify_signature,
|
};
|
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);
|
