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mirror of https://git.kernel.org/pub/scm/network/wireless/iwd.git synced 2024-12-23 06:02:37 +01:00
iwd/src/eap-tls.c
Denis Kenzior 2b2b6185e4 eap-tls: Fix potential memory leak
client-cert might be leaked if ClientKey loading fails
2021-02-08 15:56:30 -06:00

456 lines
12 KiB
C

/*
*
* Wireless daemon for Linux
*
* Copyright (C) 2013-2019 Intel Corporation. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <string.h>
#include <stdio.h>
#include <errno.h>
#include <ell/ell.h>
#include "src/missing.h"
#include "src/eap.h"
#include "src/eap-private.h"
#include "src/eap-tls-common.h"
static bool eap_tls_tunnel_ready(struct eap_state *eap,
const char *peer_identity)
{
uint8_t msk_emsk[128];
uint8_t iv[64];
eap_method_success(eap);
eap_tls_common_set_completed(eap);
/* MSK, EMSK and IV derivation */
eap_tls_common_tunnel_prf_get_bytes(eap, true, "client EAP encryption",
msk_emsk, 128);
eap_tls_common_tunnel_prf_get_bytes(eap, false, "client EAP encryption",
iv, 64);
/* TODO: Derive Session-ID */
eap_set_key_material(eap, msk_emsk + 0, 64, msk_emsk + 64, 64, iv, 64,
NULL, 0);
explicit_bzero(msk_emsk, sizeof(msk_emsk));
explicit_bzero(iv, sizeof(iv));
eap_tls_common_send_empty_response(eap);
return true;
}
static int eap_tls_check_keys_match(struct l_key *priv_key, struct l_cert *cert,
const char *key_name,
const char *cert_name)
{
bool is_public;
size_t size;
ssize_t result;
uint8_t *encrypted, *decrypted;
struct l_key *pub_key;
if (!l_key_get_info(priv_key, L_KEY_RSA_PKCS1_V1_5, L_CHECKSUM_NONE,
&size, &is_public) || is_public) {
l_error("%s is not a private key or l_key_get_info fails",
key_name);
return -EINVAL;
}
size /= 8;
encrypted = alloca(size);
decrypted = alloca(size);
pub_key = l_cert_get_pubkey(cert);
if (!pub_key) {
l_error("l_cert_get_pubkey fails for %s", cert_name);
return -EIO;
}
result = l_key_encrypt(pub_key, L_KEY_RSA_PKCS1_V1_5, L_CHECKSUM_NONE,
"", encrypted, 1, size);
l_key_free(pub_key);
if (result != (ssize_t) size) {
l_error("l_key_encrypt fails with %s: %s", cert_name,
strerror(-result));
return result;
}
result = l_key_decrypt(priv_key, L_KEY_RSA_PKCS1_V1_5, L_CHECKSUM_NONE,
encrypted, decrypted, size, size);
if (result < 0) {
l_error("l_key_decrypt fails with %s: %s", key_name,
strerror(-result));
return result;
}
if (result != 1 || decrypted[0] != 0) {
l_error("Private key %s does not match certificate %s", key_name,
cert_name);
return -EINVAL;
}
return 0;
}
static int eap_tls_settings_check(struct l_settings *settings,
struct l_queue *secrets,
const char *prefix,
struct l_queue **out_missing)
{
char tls_prefix[32];
char passphrase_setting[72];
char client_cert_setting[72];
char priv_key_setting[72];
char bundle_setting[72];
L_AUTO_FREE_VAR(char *, passphrase) = NULL;
L_AUTO_FREE_VAR(char *, client_cert_value) = NULL;
L_AUTO_FREE_VAR(char *, priv_key_value) = NULL;
L_AUTO_FREE_VAR(char *, bundle_value) = NULL;
struct l_certchain *client_cert = NULL;
struct l_key *priv_key = NULL;
const char *error_str;
bool priv_key_encrypted, cert_encrypted;
int ret;
snprintf(tls_prefix, sizeof(tls_prefix), "%sTLS-", prefix);
ret = eap_tls_common_settings_check(settings, secrets, tls_prefix,
out_missing);
if (ret < 0)
goto done;
snprintf(client_cert_setting, sizeof(client_cert_setting),
"%sClientCert", tls_prefix);
client_cert_value = l_settings_get_string(settings, "Security",
client_cert_setting);
snprintf(priv_key_setting, sizeof(priv_key_setting), "%sClientKey",
tls_prefix);
priv_key_value = l_settings_get_string(settings, "Security",
priv_key_setting);
snprintf(bundle_setting, sizeof(bundle_setting),
"%sClientKeyBundle", tls_prefix);
bundle_value = l_settings_get_string(settings, "Security",
bundle_setting);
snprintf(passphrase_setting, sizeof(passphrase_setting),
"%sClientKeyPassphrase", tls_prefix);
passphrase = l_settings_get_string(settings, "Security",
passphrase_setting);
if (!passphrase) {
const struct eap_secret_info *secret;
secret = l_queue_find(secrets, eap_secret_info_match,
passphrase_setting);
if (secret)
passphrase = l_strdup(secret->value);
}
/*
* Check whether the combination of settings that are present/missing
* makes sense before validating each setting.
*/
if (bundle_value && (priv_key_value || client_cert_value)) {
l_error("Either %s or %s/%s can be used, not both",
bundle_setting, priv_key_setting, client_cert_setting);
ret = -EEXIST;
goto done;
} else if (priv_key_value && !client_cert_value) {
l_error("%s present but no client certificate (%s)",
priv_key_setting, client_cert_setting);
ret = -ENOENT;
goto done;
} else if (!priv_key_value && client_cert_value) {
l_error("%s present but no client private key (%s)",
client_cert_setting, priv_key_setting);
ret = -ENOENT;
goto done;
}
if (!priv_key_value && !bundle_value) {
if (passphrase) {
l_error("%s present but no client keys set (%s)",
passphrase_setting, priv_key_setting);
ret = -ENOENT;
goto done;
}
ret = 0;
goto done;
}
if (bundle_value &&
(!l_cert_load_container_file(bundle_value, passphrase,
&client_cert, &priv_key,
&priv_key_encrypted) ||
!client_cert || !priv_key)) {
if (client_cert) {
l_error("No private key loaded from %s", bundle_value);
ret = -ENOKEY;
goto done;
} else if (priv_key) {
l_error("No certificates loaded from %s", bundle_value);
ret = -ENOKEY;
goto done;
} else if (!priv_key_encrypted) {
l_error("Error loading %s", bundle_value);
ret = -EIO;
goto done;
} else if (passphrase) {
l_error("Error loading key pair from encrypted file %s",
bundle_value);
ret = -EACCES;
goto done;
}
/*
* We've got an encrypted file and passphrase was not saved
* in the network settings, need to request the passphrase.
*/
eap_append_secret(out_missing,
EAP_SECRET_LOCAL_PKEY_PASSPHRASE,
passphrase_setting, NULL,
bundle_value, EAP_CACHE_TEMPORARY);
ret = 0;
goto done;
}
if (bundle_value)
goto validate_keys;
client_cert = eap_tls_load_client_cert(settings, client_cert_value,
passphrase, &cert_encrypted);
if (!client_cert) {
if (!cert_encrypted) {
l_error("Failed to load %s", client_cert_value);
ret = -EIO;
goto done;
}
if (passphrase) {
l_error("Error loading certificate from encrypted "
"file %s", client_cert_value);
ret = -EACCES;
goto done;
}
/*
* We've got an encrypted file and passphrase was not saved
* in the network settings, need to request the passphrase.
*/
eap_append_secret(out_missing,
EAP_SECRET_LOCAL_PKEY_PASSPHRASE,
passphrase_setting, NULL,
client_cert_value, EAP_CACHE_TEMPORARY);
ret = 0;
goto done;
}
priv_key = eap_tls_load_priv_key(settings, priv_key_value, passphrase,
&priv_key_encrypted);
if (!priv_key) {
if (!priv_key_encrypted) {
l_error("Error loading client private key %s",
priv_key_value);
ret = -EIO;
goto done;
}
if (passphrase) {
l_error("Error loading encrypted client private key %s",
priv_key_value);
ret = -EACCES;
goto done;
}
/*
* We've got an encrypted key and passphrase was not saved
* in the network settings, need to request the passphrase.
*/
eap_append_secret(out_missing,
EAP_SECRET_LOCAL_PKEY_PASSPHRASE,
passphrase_setting, NULL,
priv_key_value, EAP_CACHE_TEMPORARY);
ret = 0;
goto done;
}
validate_keys:
if (passphrase && !priv_key_encrypted && !cert_encrypted) {
l_error("%s present but keys are not encrypted",
passphrase_setting);
ret = -ENOENT;
goto done;
}
/*
* Sanity check that certchain provided is valid. We do not verify
* the certchain against the provided CA since the CA that issued
* user certificates might be different from the one that is used
* to verify the peer.
*/
if (!l_certchain_verify(client_cert, NULL, &error_str)) {
l_error("Certificate chain %s fails verification: %s",
client_cert_value, error_str);
ret = -EINVAL;
goto done;
}
ret = eap_tls_check_keys_match(priv_key,
l_certchain_get_leaf(client_cert),
priv_key_value, client_cert_value);
done:
l_certchain_free(client_cert);
l_key_free(priv_key);
if (passphrase)
explicit_bzero(passphrase, strlen(passphrase));
return ret;
}
static const struct eap_tls_variant_ops eap_tls_ops = {
.tunnel_ready = eap_tls_tunnel_ready,
};
static bool eap_tls_settings_load(struct eap_state *eap,
struct l_settings *settings,
const char *prefix)
{
char tls_prefix[32];
char setting_key[72];
struct l_certchain *client_cert = NULL;
struct l_key *client_key = NULL;
L_AUTO_FREE_VAR(char *, value) = NULL;
L_AUTO_FREE_VAR(char *, passphrase) = NULL;
snprintf(tls_prefix, sizeof(tls_prefix), "%sTLS-", prefix);
if (!eap_tls_common_settings_load(eap, settings, tls_prefix,
&eap_tls_ops, NULL))
return false;
snprintf(setting_key, sizeof(setting_key), "%sClientKeyPassphrase",
tls_prefix);
passphrase = l_settings_get_string(settings, "Security", setting_key);
snprintf(setting_key, sizeof(setting_key), "%sClientCert", tls_prefix);
value = l_settings_get_string(settings, "Security", setting_key);
if (value) {
client_cert = eap_tls_load_client_cert(settings, value,
passphrase, NULL);
if (!client_cert)
goto bad_client_cert;
}
l_free(value);
snprintf(setting_key, sizeof(setting_key), "%sClientKey", tls_prefix);
value = l_settings_get_string(settings, "Security", setting_key);
if (value) {
client_key = eap_tls_load_priv_key(settings, value,
passphrase, NULL);
if (!client_key)
goto bad_client_key;
}
l_free(value);
snprintf(setting_key, sizeof(setting_key), "%sClientKeyBundle",
tls_prefix);
value = l_settings_get_string(settings, "Security", setting_key);
if (value && !client_cert && !client_key &&
(!l_cert_load_container_file(value, passphrase,
&client_cert,
&client_key, NULL) ||
!client_cert || !client_key)) {
goto bad_bundle;
}
eap_tls_common_set_keys(eap, client_cert, client_key);
return true;
bad_bundle:
l_key_free(client_key);
bad_client_key:
l_certchain_free(client_cert);
bad_client_cert:
eap_tls_common_state_free(eap);
return false;
}
static struct eap_method eap_tls = {
.request_type = EAP_TYPE_TLS,
.exports_msk = true,
.name = "TLS",
.handle_request = eap_tls_common_handle_request,
.handle_retransmit = eap_tls_common_handle_retransmit,
.reset_state = eap_tls_common_state_reset,
.free = eap_tls_common_state_free,
.check_settings = eap_tls_settings_check,
.load_settings = eap_tls_settings_load,
};
static struct eap_method eap_wfa_tls = {
.request_type = EAP_TYPE_EXPANDED,
.exports_msk = true,
.name = "WFA-TLS",
.handle_request = eap_tls_common_handle_request,
.handle_retransmit = eap_tls_common_handle_retransmit,
.reset_state = eap_tls_common_state_reset,
.free = eap_tls_common_state_free,
.check_settings = eap_tls_settings_check,
.load_settings = eap_tls_settings_load,
.vendor_id = { 0x00, 0x9f, 0x68 },
.vendor_type = 0x0000000d,
};
static int eap_tls_init(void)
{
l_debug("");
if (eap_register_method(&eap_tls) < 0)
return -EPERM;
return eap_register_method(&eap_wfa_tls);
}
static void eap_tls_exit(void)
{
l_debug("");
eap_unregister_method(&eap_tls);
eap_unregister_method(&eap_wfa_tls);
}
EAP_METHOD_BUILTIN(eap_tls, eap_tls_init, eap_tls_exit)