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qemu-e2k/crypto/tlscredsx509.c
Daniel P. Berrangé a0722409bc crypto: require gnutls >= 3.1.18 for building QEMU 
gnutls 3.0.0 was released in 2011 and all the distros that are build
target platforms for QEMU [1] include it:

  RHEL-7: 3.1.18
  Debian (Stretch): 3.5.8
  Debian (Jessie): 3.3.8
  OpenBSD (ports): 3.5.18
  FreeBSD (ports): 3.5.18
  OpenSUSE Leap 15: 3.6.2
  Ubuntu (Xenial): 3.4.10
  macOS (Homebrew): 3.5.19

Based on this, it is reasonable to require gnutls >= 3.1.18 in QEMU
which allows for all conditional version checks in the code to be
removed.

[1] https://qemu.weilnetz.de/doc/qemu-doc.html#Supported-build-platforms

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
2018-10-19 12:26:57 +01:00

850 lines
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/*
* QEMU crypto TLS x509 credential support
*
* Copyright (c) 2015 Red Hat, Inc.
*
* 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 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, see <http://www.gnu.org/licenses/>.
*
*/
#include "qemu/osdep.h"
#include "crypto/tlscredsx509.h"
#include "tlscredspriv.h"
#include "crypto/secret.h"
#include "qapi/error.h"
#include "qom/object_interfaces.h"
#include "trace.h"
#ifdef CONFIG_GNUTLS
#include <gnutls/x509.h>
static int
qcrypto_tls_creds_check_cert_times(gnutls_x509_crt_t cert,
const char *certFile,
bool isServer,
bool isCA,
Error **errp)
{
time_t now = time(NULL);
if (now == ((time_t)-1)) {
error_setg_errno(errp, errno, "cannot get current time");
return -1;
}
if (gnutls_x509_crt_get_expiration_time(cert) < now) {
error_setg(errp,
(isCA ?
"The CA certificate %s has expired" :
(isServer ?
"The server certificate %s has expired" :
"The client certificate %s has expired")),
certFile);
return -1;
}
if (gnutls_x509_crt_get_activation_time(cert) > now) {
error_setg(errp,
(isCA ?
"The CA certificate %s is not yet active" :
(isServer ?
"The server certificate %s is not yet active" :
"The client certificate %s is not yet active")),
certFile);
return -1;
}
return 0;
}
static int
qcrypto_tls_creds_check_cert_basic_constraints(QCryptoTLSCredsX509 *creds,
gnutls_x509_crt_t cert,
const char *certFile,
bool isServer,
bool isCA,
Error **errp)
{
int status;
status = gnutls_x509_crt_get_basic_constraints(cert, NULL, NULL, NULL);
trace_qcrypto_tls_creds_x509_check_basic_constraints(
creds, certFile, status);
if (status > 0) { /* It is a CA cert */
if (!isCA) {
error_setg(errp, isServer ?
"The certificate %s basic constraints show a CA, "
"but we need one for a server" :
"The certificate %s basic constraints show a CA, "
"but we need one for a client",
certFile);
return -1;
}
} else if (status == 0) { /* It is not a CA cert */
if (isCA) {
error_setg(errp,
"The certificate %s basic constraints do not "
"show a CA",
certFile);
return -1;
}
} else if (status == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) {
/* Missing basicConstraints */
if (isCA) {
error_setg(errp,
"The certificate %s is missing basic constraints "
"for a CA",
certFile);
return -1;
}
} else { /* General error */
error_setg(errp,
"Unable to query certificate %s basic constraints: %s",
certFile, gnutls_strerror(status));
return -1;
}
return 0;
}
static int
qcrypto_tls_creds_check_cert_key_usage(QCryptoTLSCredsX509 *creds,
gnutls_x509_crt_t cert,
const char *certFile,
bool isCA,
Error **errp)
{
int status;
unsigned int usage = 0;
unsigned int critical = 0;
status = gnutls_x509_crt_get_key_usage(cert, &usage, &critical);
trace_qcrypto_tls_creds_x509_check_key_usage(
creds, certFile, status, usage, critical);
if (status < 0) {
if (status == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) {
usage = isCA ? GNUTLS_KEY_KEY_CERT_SIGN :
GNUTLS_KEY_DIGITAL_SIGNATURE|GNUTLS_KEY_KEY_ENCIPHERMENT;
} else {
error_setg(errp,
"Unable to query certificate %s key usage: %s",
certFile, gnutls_strerror(status));
return -1;
}
}
if (isCA) {
if (!(usage & GNUTLS_KEY_KEY_CERT_SIGN)) {
if (critical) {
error_setg(errp,
"Certificate %s usage does not permit "
"certificate signing", certFile);
return -1;
}
}
} else {
if (!(usage & GNUTLS_KEY_DIGITAL_SIGNATURE)) {
if (critical) {
error_setg(errp,
"Certificate %s usage does not permit digital "
"signature", certFile);
return -1;
}
}
if (!(usage & GNUTLS_KEY_KEY_ENCIPHERMENT)) {
if (critical) {
error_setg(errp,
"Certificate %s usage does not permit key "
"encipherment", certFile);
return -1;
}
}
}
return 0;
}
static int
qcrypto_tls_creds_check_cert_key_purpose(QCryptoTLSCredsX509 *creds,
gnutls_x509_crt_t cert,
const char *certFile,
bool isServer,
Error **errp)
{
int status;
size_t i;
unsigned int purposeCritical;
unsigned int critical;
char *buffer = NULL;
size_t size;
bool allowClient = false, allowServer = false;
critical = 0;
for (i = 0; ; i++) {
size = 0;
status = gnutls_x509_crt_get_key_purpose_oid(cert, i, buffer,
&size, NULL);
if (status == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE) {
/* If there is no data at all, then we must allow
client/server to pass */
if (i == 0) {
allowServer = allowClient = true;
}
break;
}
if (status != GNUTLS_E_SHORT_MEMORY_BUFFER) {
error_setg(errp,
"Unable to query certificate %s key purpose: %s",
certFile, gnutls_strerror(status));
return -1;
}
buffer = g_new0(char, size);
status = gnutls_x509_crt_get_key_purpose_oid(cert, i, buffer,
&size, &purposeCritical);
if (status < 0) {
trace_qcrypto_tls_creds_x509_check_key_purpose(
creds, certFile, status, "<none>", purposeCritical);
g_free(buffer);
error_setg(errp,
"Unable to query certificate %s key purpose: %s",
certFile, gnutls_strerror(status));
return -1;
}
trace_qcrypto_tls_creds_x509_check_key_purpose(
creds, certFile, status, buffer, purposeCritical);
if (purposeCritical) {
critical = true;
}
if (g_str_equal(buffer, GNUTLS_KP_TLS_WWW_SERVER)) {
allowServer = true;
} else if (g_str_equal(buffer, GNUTLS_KP_TLS_WWW_CLIENT)) {
allowClient = true;
} else if (g_str_equal(buffer, GNUTLS_KP_ANY)) {
allowServer = allowClient = true;
}
g_free(buffer);
buffer = NULL;
}
if (isServer) {
if (!allowServer) {
if (critical) {
error_setg(errp,
"Certificate %s purpose does not allow "
"use with a TLS server", certFile);
return -1;
}
}
} else {
if (!allowClient) {
if (critical) {
error_setg(errp,
"Certificate %s purpose does not allow use "
"with a TLS client", certFile);
return -1;
}
}
}
return 0;
}
static int
qcrypto_tls_creds_check_cert(QCryptoTLSCredsX509 *creds,
gnutls_x509_crt_t cert,
const char *certFile,
bool isServer,
bool isCA,
Error **errp)
{
if (qcrypto_tls_creds_check_cert_times(cert, certFile,
isServer, isCA,
errp) < 0) {
return -1;
}
if (qcrypto_tls_creds_check_cert_basic_constraints(creds,
cert, certFile,
isServer, isCA,
errp) < 0) {
return -1;
}
if (qcrypto_tls_creds_check_cert_key_usage(creds,
cert, certFile,
isCA, errp) < 0) {
return -1;
}
if (!isCA &&
qcrypto_tls_creds_check_cert_key_purpose(creds,
cert, certFile,
isServer, errp) < 0) {
return -1;
}
return 0;
}
static int
qcrypto_tls_creds_check_cert_pair(gnutls_x509_crt_t cert,
const char *certFile,
gnutls_x509_crt_t *cacerts,
size_t ncacerts,
const char *cacertFile,
bool isServer,
Error **errp)
{
unsigned int status;
if (gnutls_x509_crt_list_verify(&cert, 1,
cacerts, ncacerts,
NULL, 0,
0, &status) < 0) {
error_setg(errp, isServer ?
"Unable to verify server certificate %s against "
"CA certificate %s" :
"Unable to verify client certificate %s against "
"CA certificate %s",
certFile, cacertFile);
return -1;
}
if (status != 0) {
const char *reason = "Invalid certificate";
if (status & GNUTLS_CERT_INVALID) {
reason = "The certificate is not trusted";
}
if (status & GNUTLS_CERT_SIGNER_NOT_FOUND) {
reason = "The certificate hasn't got a known issuer";
}
if (status & GNUTLS_CERT_REVOKED) {
reason = "The certificate has been revoked";
}
#ifndef GNUTLS_1_0_COMPAT
if (status & GNUTLS_CERT_INSECURE_ALGORITHM) {
reason = "The certificate uses an insecure algorithm";
}
#endif
error_setg(errp,
"Our own certificate %s failed validation against %s: %s",
certFile, cacertFile, reason);
return -1;
}
return 0;
}
static gnutls_x509_crt_t
qcrypto_tls_creds_load_cert(QCryptoTLSCredsX509 *creds,
const char *certFile,
bool isServer,
Error **errp)
{
gnutls_datum_t data;
gnutls_x509_crt_t cert = NULL;
char *buf = NULL;
gsize buflen;
GError *gerr;
int ret = -1;
int err;
trace_qcrypto_tls_creds_x509_load_cert(creds, isServer, certFile);
err = gnutls_x509_crt_init(&cert);
if (err < 0) {
error_setg(errp, "Unable to initialize certificate: %s",
gnutls_strerror(err));
goto cleanup;
}
if (!g_file_get_contents(certFile, &buf, &buflen, &gerr)) {
error_setg(errp, "Cannot load CA cert list %s: %s",
certFile, gerr->message);
g_error_free(gerr);
goto cleanup;
}
data.data = (unsigned char *)buf;
data.size = strlen(buf);
err = gnutls_x509_crt_import(cert, &data, GNUTLS_X509_FMT_PEM);
if (err < 0) {
error_setg(errp, isServer ?
"Unable to import server certificate %s: %s" :
"Unable to import client certificate %s: %s",
certFile,
gnutls_strerror(err));
goto cleanup;
}
ret = 0;
cleanup:
if (ret != 0) {
gnutls_x509_crt_deinit(cert);
cert = NULL;
}
g_free(buf);
return cert;
}
static int
qcrypto_tls_creds_load_ca_cert_list(QCryptoTLSCredsX509 *creds,
const char *certFile,
gnutls_x509_crt_t *certs,
unsigned int certMax,
size_t *ncerts,
Error **errp)
{
gnutls_datum_t data;
char *buf = NULL;
gsize buflen;
int ret = -1;
GError *gerr = NULL;
*ncerts = 0;
trace_qcrypto_tls_creds_x509_load_cert_list(creds, certFile);
if (!g_file_get_contents(certFile, &buf, &buflen, &gerr)) {
error_setg(errp, "Cannot load CA cert list %s: %s",
certFile, gerr->message);
g_error_free(gerr);
goto cleanup;
}
data.data = (unsigned char *)buf;
data.size = strlen(buf);
if (gnutls_x509_crt_list_import(certs, &certMax, &data,
GNUTLS_X509_FMT_PEM, 0) < 0) {
error_setg(errp,
"Unable to import CA certificate list %s",
certFile);
goto cleanup;
}
*ncerts = certMax;
ret = 0;
cleanup:
g_free(buf);
return ret;
}
#define MAX_CERTS 16
static int
qcrypto_tls_creds_x509_sanity_check(QCryptoTLSCredsX509 *creds,
bool isServer,
const char *cacertFile,
const char *certFile,
Error **errp)
{
gnutls_x509_crt_t cert = NULL;
gnutls_x509_crt_t cacerts[MAX_CERTS];
size_t ncacerts = 0;
size_t i;
int ret = -1;
memset(cacerts, 0, sizeof(cacerts));
if (certFile &&
access(certFile, R_OK) == 0) {
cert = qcrypto_tls_creds_load_cert(creds,
certFile, isServer,
errp);
if (!cert) {
goto cleanup;
}
}
if (access(cacertFile, R_OK) == 0) {
if (qcrypto_tls_creds_load_ca_cert_list(creds,
cacertFile, cacerts,
MAX_CERTS, &ncacerts,
errp) < 0) {
goto cleanup;
}
}
if (cert &&
qcrypto_tls_creds_check_cert(creds,
cert, certFile, isServer,
false, errp) < 0) {
goto cleanup;
}
for (i = 0; i < ncacerts; i++) {
if (qcrypto_tls_creds_check_cert(creds,
cacerts[i], cacertFile,
isServer, true, errp) < 0) {
goto cleanup;
}
}
if (cert && ncacerts &&
qcrypto_tls_creds_check_cert_pair(cert, certFile, cacerts,
ncacerts, cacertFile,
isServer, errp) < 0) {
goto cleanup;
}
ret = 0;
cleanup:
if (cert) {
gnutls_x509_crt_deinit(cert);
}
for (i = 0; i < ncacerts; i++) {
gnutls_x509_crt_deinit(cacerts[i]);
}
return ret;
}
static int
qcrypto_tls_creds_x509_load(QCryptoTLSCredsX509 *creds,
Error **errp)
{
char *cacert = NULL, *cacrl = NULL, *cert = NULL,
*key = NULL, *dhparams = NULL;
int ret;
int rv = -1;
trace_qcrypto_tls_creds_x509_load(creds,
creds->parent_obj.dir ? creds->parent_obj.dir : "<nodir>");
if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
if (qcrypto_tls_creds_get_path(&creds->parent_obj,
QCRYPTO_TLS_CREDS_X509_CA_CERT,
true, &cacert, errp) < 0 ||
qcrypto_tls_creds_get_path(&creds->parent_obj,
QCRYPTO_TLS_CREDS_X509_CA_CRL,
false, &cacrl, errp) < 0 ||
qcrypto_tls_creds_get_path(&creds->parent_obj,
QCRYPTO_TLS_CREDS_X509_SERVER_CERT,
true, &cert, errp) < 0 ||
qcrypto_tls_creds_get_path(&creds->parent_obj,
QCRYPTO_TLS_CREDS_X509_SERVER_KEY,
true, &key, errp) < 0 ||
qcrypto_tls_creds_get_path(&creds->parent_obj,
QCRYPTO_TLS_CREDS_DH_PARAMS,
false, &dhparams, errp) < 0) {
goto cleanup;
}
} else {
if (qcrypto_tls_creds_get_path(&creds->parent_obj,
QCRYPTO_TLS_CREDS_X509_CA_CERT,
true, &cacert, errp) < 0 ||
qcrypto_tls_creds_get_path(&creds->parent_obj,
QCRYPTO_TLS_CREDS_X509_CLIENT_CERT,
false, &cert, errp) < 0 ||
qcrypto_tls_creds_get_path(&creds->parent_obj,
QCRYPTO_TLS_CREDS_X509_CLIENT_KEY,
false, &key, errp) < 0) {
goto cleanup;
}
}
if (creds->sanityCheck &&
qcrypto_tls_creds_x509_sanity_check(creds,
creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER,
cacert, cert, errp) < 0) {
goto cleanup;
}
ret = gnutls_certificate_allocate_credentials(&creds->data);
if (ret < 0) {
error_setg(errp, "Cannot allocate credentials: '%s'",
gnutls_strerror(ret));
goto cleanup;
}
ret = gnutls_certificate_set_x509_trust_file(creds->data,
cacert,
GNUTLS_X509_FMT_PEM);
if (ret < 0) {
error_setg(errp, "Cannot load CA certificate '%s': %s",
cacert, gnutls_strerror(ret));
goto cleanup;
}
if (cert != NULL && key != NULL) {
char *password = NULL;
if (creds->passwordid) {
password = qcrypto_secret_lookup_as_utf8(creds->passwordid,
errp);
if (!password) {
goto cleanup;
}
}
ret = gnutls_certificate_set_x509_key_file2(creds->data,
cert, key,
GNUTLS_X509_FMT_PEM,
password,
0);
g_free(password);
if (ret < 0) {
error_setg(errp, "Cannot load certificate '%s' & key '%s': %s",
cert, key, gnutls_strerror(ret));
goto cleanup;
}
}
if (cacrl != NULL) {
ret = gnutls_certificate_set_x509_crl_file(creds->data,
cacrl,
GNUTLS_X509_FMT_PEM);
if (ret < 0) {
error_setg(errp, "Cannot load CRL '%s': %s",
cacrl, gnutls_strerror(ret));
goto cleanup;
}
}
if (creds->parent_obj.endpoint == QCRYPTO_TLS_CREDS_ENDPOINT_SERVER) {
if (qcrypto_tls_creds_get_dh_params_file(&creds->parent_obj, dhparams,
&creds->parent_obj.dh_params,
errp) < 0) {
goto cleanup;
}
gnutls_certificate_set_dh_params(creds->data,
creds->parent_obj.dh_params);
}
rv = 0;
cleanup:
g_free(cacert);
g_free(cacrl);
g_free(cert);
g_free(key);
g_free(dhparams);
return rv;
}
static void
qcrypto_tls_creds_x509_unload(QCryptoTLSCredsX509 *creds)
{
if (creds->data) {
gnutls_certificate_free_credentials(creds->data);
creds->data = NULL;
}
if (creds->parent_obj.dh_params) {
gnutls_dh_params_deinit(creds->parent_obj.dh_params);
creds->parent_obj.dh_params = NULL;
}
}
#else /* ! CONFIG_GNUTLS */
static void
qcrypto_tls_creds_x509_load(QCryptoTLSCredsX509 *creds G_GNUC_UNUSED,
Error **errp)
{
error_setg(errp, "TLS credentials support requires GNUTLS");
}
static void
qcrypto_tls_creds_x509_unload(QCryptoTLSCredsX509 *creds G_GNUC_UNUSED)
{
/* nada */
}
#endif /* ! CONFIG_GNUTLS */
static void
qcrypto_tls_creds_x509_prop_set_loaded(Object *obj,
bool value,
Error **errp)
{
QCryptoTLSCredsX509 *creds = QCRYPTO_TLS_CREDS_X509(obj);
if (value) {
qcrypto_tls_creds_x509_load(creds, errp);
} else {
qcrypto_tls_creds_x509_unload(creds);
}
}
#ifdef CONFIG_GNUTLS
static bool
qcrypto_tls_creds_x509_prop_get_loaded(Object *obj,
Error **errp G_GNUC_UNUSED)
{
QCryptoTLSCredsX509 *creds = QCRYPTO_TLS_CREDS_X509(obj);
return creds->data != NULL;
}
#else /* ! CONFIG_GNUTLS */
static bool
qcrypto_tls_creds_x509_prop_get_loaded(Object *obj G_GNUC_UNUSED,
Error **errp G_GNUC_UNUSED)
{
return false;
}
#endif /* ! CONFIG_GNUTLS */
static void
qcrypto_tls_creds_x509_prop_set_sanity(Object *obj,
bool value,
Error **errp G_GNUC_UNUSED)
{
QCryptoTLSCredsX509 *creds = QCRYPTO_TLS_CREDS_X509(obj);
creds->sanityCheck = value;
}
static void
qcrypto_tls_creds_x509_prop_set_passwordid(Object *obj,
const char *value,
Error **errp G_GNUC_UNUSED)
{
QCryptoTLSCredsX509 *creds = QCRYPTO_TLS_CREDS_X509(obj);
creds->passwordid = g_strdup(value);
}
static char *
qcrypto_tls_creds_x509_prop_get_passwordid(Object *obj,
Error **errp G_GNUC_UNUSED)
{
QCryptoTLSCredsX509 *creds = QCRYPTO_TLS_CREDS_X509(obj);
return g_strdup(creds->passwordid);
}
static bool
qcrypto_tls_creds_x509_prop_get_sanity(Object *obj,
Error **errp G_GNUC_UNUSED)
{
QCryptoTLSCredsX509 *creds = QCRYPTO_TLS_CREDS_X509(obj);
return creds->sanityCheck;
}
static void
qcrypto_tls_creds_x509_complete(UserCreatable *uc, Error **errp)
{
object_property_set_bool(OBJECT(uc), true, "loaded", errp);
}
static void
qcrypto_tls_creds_x509_init(Object *obj)
{
QCryptoTLSCredsX509 *creds = QCRYPTO_TLS_CREDS_X509(obj);
creds->sanityCheck = true;
}
static void
qcrypto_tls_creds_x509_finalize(Object *obj)
{
QCryptoTLSCredsX509 *creds = QCRYPTO_TLS_CREDS_X509(obj);
g_free(creds->passwordid);
qcrypto_tls_creds_x509_unload(creds);
}
static void
qcrypto_tls_creds_x509_class_init(ObjectClass *oc, void *data)
{
UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
ucc->complete = qcrypto_tls_creds_x509_complete;
object_class_property_add_bool(oc, "loaded",
qcrypto_tls_creds_x509_prop_get_loaded,
qcrypto_tls_creds_x509_prop_set_loaded,
NULL);
object_class_property_add_bool(oc, "sanity-check",
qcrypto_tls_creds_x509_prop_get_sanity,
qcrypto_tls_creds_x509_prop_set_sanity,
NULL);
object_class_property_add_str(oc, "passwordid",
qcrypto_tls_creds_x509_prop_get_passwordid,
qcrypto_tls_creds_x509_prop_set_passwordid,
NULL);
}
static const TypeInfo qcrypto_tls_creds_x509_info = {
.parent = TYPE_QCRYPTO_TLS_CREDS,
.name = TYPE_QCRYPTO_TLS_CREDS_X509,
.instance_size = sizeof(QCryptoTLSCredsX509),
.instance_init = qcrypto_tls_creds_x509_init,
.instance_finalize = qcrypto_tls_creds_x509_finalize,
.class_size = sizeof(QCryptoTLSCredsX509Class),
.class_init = qcrypto_tls_creds_x509_class_init,
.interfaces = (InterfaceInfo[]) {
{ TYPE_USER_CREATABLE },
{ }
}
};
static void
qcrypto_tls_creds_x509_register_types(void)
{
type_register_static(&qcrypto_tls_creds_x509_info);
}
type_init(qcrypto_tls_creds_x509_register_types);
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