static int vnc_start_vencrypt_handshake(struct VncState *vs) {
int ret;
if ((ret = gnutls_handshake(vs->tls.session)) < 0) {
if (!gnutls_error_is_fatal(ret)) {
VNC_DEBUG("Handshake interrupted (blocking)\n");
if (!gnutls_record_get_direction(vs->tls.session))
qemu_set_fd_handler(vs->csock, vnc_tls_handshake_io, NULL, vs);
else
qemu_set_fd_handler(vs->csock, NULL, vnc_tls_handshake_io, vs);
return 0;
}
VNC_DEBUG("Handshake failed %s\n", gnutls_strerror(ret));
vnc_client_error(vs);
return -1;
}
if (vs->vd->tls.x509verify) {
if (vnc_tls_validate_certificate(vs) < 0) {
VNC_DEBUG("Client verification failed\n");
vnc_client_error(vs);
return -1;
} else {
VNC_DEBUG("Client verification passed\n");
}
}
VNC_DEBUG("Handshake done, switching to TLS data mode\n");
vs->tls.wiremode = VNC_WIREMODE_TLS;
qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, vnc_client_write, vs);
start_auth_vencrypt_subauth(vs);
return 0;
}
static int protocol_client_vencrypt_auth(VncState *vs, uint8_t *data, size_t len)
{
int auth = read_u32(data, 0);
trace_vnc_auth_vencrypt_subauth(vs, auth);
if (auth != vs->subauth) {
trace_vnc_auth_fail(vs, vs->auth, "Unsupported sub-auth version", "");
vnc_write_u8(vs, 0); /* Reject auth */
vnc_flush(vs);
vnc_client_error(vs);
} else {
Error *err = NULL;
QIOChannelTLS *tls;
vnc_write_u8(vs, 1); /* Accept auth */
vnc_flush(vs);
if (vs->ioc_tag) {
g_source_remove(vs->ioc_tag);
vs->ioc_tag = 0;
}
tls = qio_channel_tls_new_server(
vs->ioc,
vs->vd->tlscreds,
vs->vd->tlsauthzid,
&err);
if (!tls) {
trace_vnc_auth_fail(vs, vs->auth, "TLS setup failed",
error_get_pretty(err));
error_free(err);
vnc_client_error(vs);
return 0;
}
qio_channel_set_name(QIO_CHANNEL(tls), "vnc-server-tls");
object_unref(OBJECT(vs->ioc));
vs->ioc = QIO_CHANNEL(tls);
trace_vnc_client_io_wrap(vs, vs->ioc, "tls");
vs->tls = qio_channel_tls_get_session(tls);
qio_channel_tls_handshake(tls,
vnc_tls_handshake_done,
vs,
NULL,
NULL);
}
return 0;
}
void vncws_tls_handshake_io(void *opaque)
{
VncState *vs = (VncState *)opaque;
Error *err = NULL;
vs->tls = qcrypto_tls_session_new(vs->vd->tlscreds,
NULL,
vs->vd->tlsaclname,
QCRYPTO_TLS_CREDS_ENDPOINT_SERVER,
&err);
if (!vs->tls) {
VNC_DEBUG("Failed to setup TLS %s\n",
error_get_pretty(err));
error_free(err);
vnc_client_error(vs);
return;
}
qcrypto_tls_session_set_callbacks(vs->tls,
vnc_tls_push,
vnc_tls_pull,
vs);
VNC_DEBUG("Start TLS WS handshake process\n");
vncws_start_tls_handshake(vs);
}
static void vncws_send_handshake_response(VncState *vs, const char* key)
{
char combined_key[WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1];
char *accept = NULL, *response = NULL;
Error *err = NULL;
g_strlcpy(combined_key, key, WS_CLIENT_KEY_LEN + 1);
g_strlcat(combined_key, WS_GUID, WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1);
/* hash and encode it */
if (qcrypto_hash_base64(QCRYPTO_HASH_ALG_SHA1,
combined_key,
WS_CLIENT_KEY_LEN + WS_GUID_LEN,
&accept,
&err) < 0) {
VNC_DEBUG("Hashing Websocket combined key failed %s\n",
error_get_pretty(err));
error_free(err);
vnc_client_error(vs);
return;
}
response = g_strdup_printf(WS_HANDSHAKE, accept);
vnc_client_write_buf(vs, (const uint8_t *)response, strlen(response));
g_free(accept);
g_free(response);
vs->encode_ws = 1;
vnc_init_state(vs);
}
static int protocol_client_vencrypt_auth(VncState *vs, uint8_t *data, size_t len)
{
int auth = read_u32(data, 0);
if (auth != vs->vd->subauth) {
VNC_DEBUG("Rejecting auth %d\n", auth);
vnc_write_u8(vs, 0); /* Reject auth */
vnc_flush(vs);
vnc_client_error(vs);
} else {
VNC_DEBUG("Accepting auth %d, setting up TLS for handshake\n", auth);
vnc_write_u8(vs, 1); /* Accept auth */
vnc_flush(vs);
if (vnc_tls_client_setup(vs, NEED_X509_AUTH(vs)) < 0) {
VNC_DEBUG("Failed to setup TLS\n");
return 0;
}
VNC_DEBUG("Start TLS VeNCrypt handshake process\n");
if (vnc_start_vencrypt_handshake(vs) < 0) {
VNC_DEBUG("Failed to start TLS handshake\n");
return 0;
}
}
return 0;
}
static void start_auth_vencrypt_subauth(VncState *vs)
{
switch (vs->subauth) {
case VNC_AUTH_VENCRYPT_TLSNONE:
case VNC_AUTH_VENCRYPT_X509NONE:
VNC_DEBUG("Accept TLS auth none\n");
vnc_write_u32(vs, 0); /* Accept auth completion */
start_client_init(vs);
break;
case VNC_AUTH_VENCRYPT_TLSVNC:
case VNC_AUTH_VENCRYPT_X509VNC:
VNC_DEBUG("Start TLS auth VNC\n");
start_auth_vnc(vs);
break;
#ifdef CONFIG_VNC_SASL
case VNC_AUTH_VENCRYPT_TLSSASL:
case VNC_AUTH_VENCRYPT_X509SASL:
VNC_DEBUG("Start TLS auth SASL\n");
start_auth_sasl(vs);
break;
#endif /* CONFIG_VNC_SASL */
default: /* Should not be possible, but just in case */
VNC_DEBUG("Reject subauth %d server bug\n", vs->auth);
vnc_write_u8(vs, 1);
if (vs->minor >= 8) {
static const char err[] = "Unsupported authentication type";
vnc_write_u32(vs, sizeof(err));
vnc_write(vs, err, sizeof(err));
}
vnc_client_error(vs);
}
}
static void start_auth_vencrypt_subauth(VncState *vs)
{
switch (vs->subauth) {
case VNC_AUTH_VENCRYPT_TLSNONE:
case VNC_AUTH_VENCRYPT_X509NONE:
vnc_write_u32(vs, 0); /* Accept auth completion */
start_client_init(vs);
break;
case VNC_AUTH_VENCRYPT_TLSVNC:
case VNC_AUTH_VENCRYPT_X509VNC:
start_auth_vnc(vs);
break;
#ifdef CONFIG_VNC_SASL
case VNC_AUTH_VENCRYPT_TLSSASL:
case VNC_AUTH_VENCRYPT_X509SASL:
start_auth_sasl(vs);
break;
#endif /* CONFIG_VNC_SASL */
default: /* Should not be possible, but just in case */
trace_vnc_auth_fail(vs, vs->auth, "Unhandled VeNCrypt subauth", "");
vnc_write_u8(vs, 1);
if (vs->minor >= 8) {
static const char err[] = "Unsupported authentication type";
vnc_write_u32(vs, sizeof(err));
vnc_write(vs, err, sizeof(err));
}
vnc_client_error(vs);
}
}
void vncws_handshake_read(void *opaque)
{
VncState *vs = opaque;
uint8_t *handshake_end;
long ret;
/* Typical HTTP headers from novnc are 512 bytes, so limiting
* total header size to 4096 is easily enough. */
size_t want = 4096 - vs->ws_input.offset;
buffer_reserve(&vs->ws_input, want);
ret = vnc_client_read_buf(vs, buffer_end(&vs->ws_input), want);
if (!ret) {
if (vs->csock == -1) {
vnc_disconnect_finish(vs);
}
return;
}
vs->ws_input.offset += ret;
handshake_end = (uint8_t *)g_strstr_len((char *)vs->ws_input.buffer,
vs->ws_input.offset, WS_HANDSHAKE_END);
if (handshake_end) {
qemu_set_fd_handler2(vs->csock, NULL, vnc_client_read, NULL, vs);
vncws_process_handshake(vs, vs->ws_input.buffer, vs->ws_input.offset);
buffer_advance(&vs->ws_input, handshake_end - vs->ws_input.buffer +
strlen(WS_HANDSHAKE_END));
} else if (vs->ws_input.offset >= 4096) {
VNC_DEBUG("End of headers not found in first 4096 bytes\n");
vnc_client_error(vs);
}
}
static void vncws_send_handshake_response(VncState *vs, const char* key)
{
char combined_key[WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1];
unsigned char hash[SHA1_DIGEST_LEN];
size_t hash_size = sizeof(hash);
char *accept = NULL, *response = NULL;
gnutls_datum_t in;
int ret;
g_strlcpy(combined_key, key, WS_CLIENT_KEY_LEN + 1);
g_strlcat(combined_key, WS_GUID, WS_CLIENT_KEY_LEN + WS_GUID_LEN + 1);
/* hash and encode it */
in.data = (void *)combined_key;
in.size = WS_CLIENT_KEY_LEN + WS_GUID_LEN;
ret = gnutls_fingerprint(GNUTLS_DIG_SHA1, &in, hash, &hash_size);
if (ret == GNUTLS_E_SUCCESS && hash_size <= SHA1_DIGEST_LEN) {
accept = g_base64_encode(hash, hash_size);
}
if (accept == NULL) {
VNC_DEBUG("Hashing Websocket combined key failed\n");
vnc_client_error(vs);
return;
}
response = g_strdup_printf(WS_HANDSHAKE, accept);
vnc_client_write_buf(vs, (const uint8_t *)response, strlen(response));
g_free(accept);
g_free(response);
vs->encode_ws = 1;
vnc_init_state(vs);
}
static int vncws_start_tls_handshake(struct VncState *vs)
{
int ret = gnutls_handshake(vs->ws_tls.session);
if (ret < 0) {
if (!gnutls_error_is_fatal(ret)) {
VNC_DEBUG("Handshake interrupted (blocking)\n");
if (!gnutls_record_get_direction(vs->ws_tls.session)) {
qemu_set_fd_handler(vs->csock, vncws_tls_handshake_io,
NULL, vs);
} else {
qemu_set_fd_handler(vs->csock, NULL, vncws_tls_handshake_io,
vs);
}
return 0;
}
VNC_DEBUG("Handshake failed %s\n", gnutls_strerror(ret));
vnc_client_error(vs);
return -1;
}
VNC_DEBUG("Handshake done, switching to TLS data mode\n");
vs->ws_tls.wiremode = VNC_WIREMODE_TLS;
qemu_set_fd_handler2(vs->csock, NULL, vncws_handshake_read, NULL, vs);
return 0;
}
static int protocol_client_auth_sasl_mechname_len(VncState *vs, uint8_t *data, size_t len)
{
uint32_t mechlen = read_u32(data, 0);
VNC_DEBUG("Got client mechname len %d\n", mechlen);
if (mechlen > 100) {
VNC_DEBUG("Too long SASL mechname data %d\n", mechlen);
vnc_client_error(vs);
return -1;
}
if (mechlen < 1) {
VNC_DEBUG("Too short SASL mechname %d\n", mechlen);
vnc_client_error(vs);
return -1;
}
vnc_read_when(vs, protocol_client_auth_sasl_mechname,mechlen);
return 0;
}
static int protocol_client_vencrypt_auth(VncState *vs, uint8_t *data, size_t len)
{
int auth = read_u32(data, 0);
if (auth != vs->subauth) {
VNC_DEBUG("Rejecting auth %d\n", auth);
vnc_write_u8(vs, 0); /* Reject auth */
vnc_flush(vs);
vnc_client_error(vs);
} else {
Error *err = NULL;
QIOChannelTLS *tls;
VNC_DEBUG("Accepting auth %d, setting up TLS for handshake\n", auth);
vnc_write_u8(vs, 1); /* Accept auth */
vnc_flush(vs);
if (vs->ioc_tag) {
g_source_remove(vs->ioc_tag);
vs->ioc_tag = 0;
}
tls = qio_channel_tls_new_server(
vs->ioc,
vs->vd->tlscreds,
vs->vd->tlsaclname,
&err);
if (!tls) {
VNC_DEBUG("Failed to setup TLS %s\n", error_get_pretty(err));
error_free(err);
vnc_client_error(vs);
return 0;
}
VNC_DEBUG("Start TLS VeNCrypt handshake process\n");
object_unref(OBJECT(vs->ioc));
vs->ioc = QIO_CHANNEL(tls);
vs->tls = qio_channel_tls_get_session(tls);
qio_channel_tls_handshake(tls,
vnc_tls_handshake_done,
vs,
NULL);
}
return 0;
}
static int protocol_client_auth_sasl_mechname(VncState *vs, uint8_t *data, size_t len)
{
char *mechname = malloc(len + 1);
if (!mechname) {
VNC_DEBUG("Out of memory reading mechname\n");
vnc_client_error(vs);
}
strncpy(mechname, (char*)data, len);
mechname[len] = '\0';
VNC_DEBUG("Got client mechname '%s' check against '%s'\n",
mechname, vs->sasl.mechlist);
if (strncmp(vs->sasl.mechlist, mechname, len) == 0) {
if (vs->sasl.mechlist[len] != '\0' &&
vs->sasl.mechlist[len] != ',') {
VNC_DEBUG("One %d", vs->sasl.mechlist[len]);
vnc_client_error(vs);
return -1;
}
} else {
char *offset = strstr(vs->sasl.mechlist, mechname);
VNC_DEBUG("Two %p\n", offset);
if (!offset) {
vnc_client_error(vs);
return -1;
}
VNC_DEBUG("Two '%s'\n", offset);
if (offset[-1] != ',' ||
(offset[len] != '\0'&&
offset[len] != ',')) {
vnc_client_error(vs);
return -1;
}
}
free(vs->sasl.mechlist);
vs->sasl.mechlist = mechname;
VNC_DEBUG("Validated mechname '%s'\n", mechname);
vnc_read_when(vs, protocol_client_auth_sasl_start_len, 4);
return 0;
}
static void vncws_tls_handshake_done(Object *source,
Error *err,
gpointer user_data)
{
VncState *vs = user_data;
if (err) {
VNC_DEBUG("Handshake failed %s\n", error_get_pretty(err));
vnc_client_error(vs);
} else {
VNC_DEBUG("TLS handshake complete, starting websocket handshake\n");
vs->ioc_tag = qio_channel_add_watch(
QIO_CHANNEL(vs->ioc), G_IO_IN, vncws_handshake_io, vs, NULL);
}
}
static int vncws_start_tls_handshake(struct VncState *vs)
{
int ret = gnutls_handshake(vs->tls.session);
if (ret < 0) {
if (!gnutls_error_is_fatal(ret)) {
VNC_DEBUG("Handshake interrupted (blocking)\n");
if (!gnutls_record_get_direction(vs->tls.session)) {
qemu_set_fd_handler(vs->csock, vncws_tls_handshake_io,
NULL, vs);
} else {
qemu_set_fd_handler(vs->csock, NULL, vncws_tls_handshake_io,
vs);
}
return 0;
}
VNC_DEBUG("Handshake failed %s\n", gnutls_strerror(ret));
vnc_client_error(vs);
return -1;
}
if (vs->vd->tls.x509verify) {
if (vnc_tls_validate_certificate(vs) < 0) {
VNC_DEBUG("Client verification failed\n");
vnc_client_error(vs);
return -1;
} else {
VNC_DEBUG("Client verification passed\n");
}
}
VNC_DEBUG("Handshake done, switching to TLS data mode\n");
qemu_set_fd_handler2(vs->csock, NULL, vncws_handshake_read, NULL, vs);
return 0;
}
static void vnc_tls_handshake_done(Object *source,
Error *err,
gpointer user_data)
{
VncState *vs = user_data;
if (err) {
VNC_DEBUG("Handshake failed %s\n",
error_get_pretty(err));
vnc_client_error(vs);
} else {
vs->ioc_tag = qio_channel_add_watch(
vs->ioc, G_IO_IN | G_IO_OUT, vnc_client_io, vs, NULL);
start_auth_vencrypt_subauth(vs);
}
}
static int protocol_client_auth_sasl_start_len(VncState *vs, uint8_t *data, size_t len)
{
uint32_t startlen = read_u32(data, 0);
VNC_DEBUG("Got client start len %d\n", startlen);
if (startlen > SASL_DATA_MAX_LEN) {
VNC_DEBUG("Too much SASL data %d\n", startlen);
vnc_client_error(vs);
return -1;
}
if (startlen == 0)
return protocol_client_auth_sasl_start(vs, NULL, 0);
vnc_read_when(vs, protocol_client_auth_sasl_start, startlen);
return 0;
}
static int protocol_client_vencrypt_init(VncState *vs, uint8_t *data, size_t len)
{
trace_vnc_auth_vencrypt_version(vs, (int)data[0], (int)data[1]);
if (data[0] != 0 ||
data[1] != 2) {
trace_vnc_auth_fail(vs, vs->auth, "Unsupported version", "");
vnc_write_u8(vs, 1); /* Reject version */
vnc_flush(vs);
vnc_client_error(vs);
} else {
vnc_write_u8(vs, 0); /* Accept version */
vnc_write_u8(vs, 1); /* Number of sub-auths */
vnc_write_u32(vs, vs->subauth); /* The supported auth */
vnc_flush(vs);
vnc_read_when(vs, protocol_client_vencrypt_auth, 4);
}
return 0;
}
static int protocol_client_vencrypt_init(VncState *vs, uint8_t *data, size_t len)
{
if (data[0] != 0 ||
data[1] != 2) {
VNC_DEBUG("Unsupported VeNCrypt protocol %d.%d\n", (int)data[0], (int)data[1]);
vnc_write_u8(vs, 1); /* Reject version */
vnc_flush(vs);
vnc_client_error(vs);
} else {
VNC_DEBUG("Sending allowed auth %d\n", vs->subauth);
vnc_write_u8(vs, 0); /* Accept version */
vnc_write_u8(vs, 1); /* Number of sub-auths */
vnc_write_u32(vs, vs->subauth); /* The supported auth */
vnc_flush(vs);
vnc_read_when(vs, protocol_client_vencrypt_auth, 4);
}
return 0;
}
static void vncws_tls_handshake_done(QIOTask *task,
gpointer user_data)
{
VncState *vs = user_data;
Error *err = NULL;
if (qio_task_propagate_error(task, &err)) {
VNC_DEBUG("Handshake failed %s\n", error_get_pretty(err));
vnc_client_error(vs);
error_free(err);
} else {
VNC_DEBUG("TLS handshake complete, starting websocket handshake\n");
if (vs->ioc_tag) {
g_source_remove(vs->ioc_tag);
}
vs->ioc_tag = qio_channel_add_watch(
QIO_CHANNEL(vs->ioc), G_IO_IN, vncws_handshake_io, vs, NULL);
}
}
static void vnc_tls_handshake_done(QIOTask *task,
gpointer user_data)
{
VncState *vs = user_data;
Error *err = NULL;
if (qio_task_propagate_error(task, &err)) {
trace_vnc_auth_fail(vs, vs->auth, "TLS handshake failed",
error_get_pretty(err));
vnc_client_error(vs);
error_free(err);
} else {
if (vs->ioc_tag) {
g_source_remove(vs->ioc_tag);
}
vs->ioc_tag = qio_channel_add_watch(
vs->ioc, G_IO_IN | G_IO_OUT, vnc_client_io, vs, NULL);
start_auth_vencrypt_subauth(vs);
}
}
static int protocol_client_auth_sasl_mechname(VncState *vs, uint8_t *data, size_t len)
{
char *mechname = g_strndup((const char *) data, len);
VNC_DEBUG("Got client mechname '%s' check against '%s'\n",
mechname, vs->sasl.mechlist);
if (strncmp(vs->sasl.mechlist, mechname, len) == 0) {
if (vs->sasl.mechlist[len] != '\0' &&
vs->sasl.mechlist[len] != ',') {
VNC_DEBUG("One %d", vs->sasl.mechlist[len]);
goto fail;
}
} else {
char *offset = strstr(vs->sasl.mechlist, mechname);
VNC_DEBUG("Two %p\n", offset);
if (!offset) {
goto fail;
}
VNC_DEBUG("Two '%s'\n", offset);
if (offset[-1] != ',' ||
(offset[len] != '\0'&&
offset[len] != ',')) {
goto fail;
}
}
g_free(vs->sasl.mechlist);
vs->sasl.mechlist = mechname;
VNC_DEBUG("Validated mechname '%s'\n", mechname);
vnc_read_when(vs, protocol_client_auth_sasl_start_len, 4);
return 0;
fail:
vnc_client_error(vs);
g_free(mechname);
return -1;
}
void vncws_process_handshake(VncState *vs, uint8_t *line, size_t size)
{
char *protocols = vncws_extract_handshake_entry((const char *)line, size,
"Sec-WebSocket-Protocol");
char *version = vncws_extract_handshake_entry((const char *)line, size,
"Sec-WebSocket-Version");
char *key = vncws_extract_handshake_entry((const char *)line, size,
"Sec-WebSocket-Key");
if (protocols && version && key
&& g_strrstr(protocols, "binary")
&& !strcmp(version, WS_SUPPORTED_VERSION)
&& strlen(key) == WS_CLIENT_KEY_LEN) {
vncws_send_handshake_response(vs, key);
} else {
VNC_DEBUG("Defective Websockets header or unsupported protocol\n");
vnc_client_error(vs);
}
g_free(protocols);
g_free(version);
g_free(key);
}
static int vncws_start_tls_handshake(VncState *vs)
{
Error *err = NULL;
if (qcrypto_tls_session_handshake(vs->tls, &err) < 0) {
goto error;
}
switch (qcrypto_tls_session_get_handshake_status(vs->tls)) {
case QCRYPTO_TLS_HANDSHAKE_COMPLETE:
VNC_DEBUG("Handshake done, checking credentials\n");
if (qcrypto_tls_session_check_credentials(vs->tls, &err) < 0) {
goto error;
}
VNC_DEBUG("Client verification passed, starting TLS I/O\n");
qemu_set_fd_handler(vs->csock, vncws_handshake_read, NULL, vs);
break;
case QCRYPTO_TLS_HANDSHAKE_RECVING:
VNC_DEBUG("Handshake interrupted (blocking read)\n");
qemu_set_fd_handler(vs->csock, vncws_tls_handshake_io, NULL, vs);
break;
case QCRYPTO_TLS_HANDSHAKE_SENDING:
VNC_DEBUG("Handshake interrupted (blocking write)\n");
qemu_set_fd_handler(vs->csock, NULL, vncws_tls_handshake_io, vs);
break;
}
return 0;
error:
VNC_DEBUG("Handshake failed %s\n", error_get_pretty(err));
error_free(err);
vnc_client_error(vs);
return -1;
}
int vnc_tls_client_setup(struct VncState *vs,
int needX509Creds) {
static const int cert_type_priority[] = { GNUTLS_CRT_X509, 0 };
static const int protocol_priority[]= { GNUTLS_TLS1_1, GNUTLS_TLS1_0, GNUTLS_SSL3, 0 };
static const int kx_anon[] = {GNUTLS_KX_ANON_DH, 0};
static const int kx_x509[] = {GNUTLS_KX_DHE_DSS, GNUTLS_KX_RSA, GNUTLS_KX_DHE_RSA, GNUTLS_KX_SRP, 0};
VNC_DEBUG("Do TLS setup\n");
if (vnc_tls_initialize() < 0) {
VNC_DEBUG("Failed to init TLS\n");
vnc_client_error(vs);
return -1;
}
if (vs->tls.session == NULL) {
if (gnutls_init(&vs->tls.session, GNUTLS_SERVER) < 0) {
vnc_client_error(vs);
return -1;
}
if (gnutls_set_default_priority(vs->tls.session) < 0) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
vnc_client_error(vs);
return -1;
}
if (gnutls_kx_set_priority(vs->tls.session, needX509Creds ? kx_x509 : kx_anon) < 0) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
vnc_client_error(vs);
return -1;
}
if (gnutls_certificate_type_set_priority(vs->tls.session, cert_type_priority) < 0) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
vnc_client_error(vs);
return -1;
}
if (gnutls_protocol_set_priority(vs->tls.session, protocol_priority) < 0) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
vnc_client_error(vs);
return -1;
}
if (needX509Creds) {
gnutls_certificate_server_credentials x509_cred = vnc_tls_initialize_x509_cred(vs->vd);
if (!x509_cred) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
vnc_client_error(vs);
return -1;
}
if (gnutls_credentials_set(vs->tls.session, GNUTLS_CRD_CERTIFICATE, x509_cred) < 0) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
gnutls_certificate_free_credentials(x509_cred);
vnc_client_error(vs);
return -1;
}
if (vs->vd->tls.x509verify) {
VNC_DEBUG("Requesting a client certificate\n");
gnutls_certificate_server_set_request (vs->tls.session, GNUTLS_CERT_REQUEST);
}
} else {
gnutls_anon_server_credentials anon_cred = vnc_tls_initialize_anon_cred();
if (!anon_cred) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
vnc_client_error(vs);
return -1;
}
if (gnutls_credentials_set(vs->tls.session, GNUTLS_CRD_ANON, anon_cred) < 0) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
gnutls_anon_free_server_credentials(anon_cred);
vnc_client_error(vs);
return -1;
}
}
gnutls_transport_set_ptr(vs->tls.session, (gnutls_transport_ptr_t)vs);
gnutls_transport_set_push_function(vs->tls.session, vnc_tls_push);
gnutls_transport_set_pull_function(vs->tls.session, vnc_tls_pull);
}
return 0;
}
static int protocol_client_auth_sasl_start(VncState *vs, uint8_t *data, size_t len)
{
uint32_t datalen = len;
const char *serverout;
unsigned int serveroutlen;
int err;
char *clientdata = NULL;
/* NB, distinction of NULL vs "" is *critical* in SASL */
if (datalen) {
clientdata = (char*)data;
clientdata[datalen-1] = '\0'; /* Should be on wire, but make sure */
datalen--; /* Don't count NULL byte when passing to _start() */
}
VNC_DEBUG("Start SASL auth with mechanism %s. Data %p (%d bytes)\n",
vs->sasl.mechlist, clientdata, datalen);
err = sasl_server_start(vs->sasl.conn,
vs->sasl.mechlist,
clientdata,
datalen,
&serverout,
&serveroutlen);
if (err != SASL_OK &&
err != SASL_CONTINUE) {
VNC_DEBUG("sasl start failed %d (%s)\n",
err, sasl_errdetail(vs->sasl.conn));
sasl_dispose(&vs->sasl.conn);
vs->sasl.conn = NULL;
goto authabort;
}
if (serveroutlen > SASL_DATA_MAX_LEN) {
VNC_DEBUG("sasl start reply data too long %d\n",
serveroutlen);
sasl_dispose(&vs->sasl.conn);
vs->sasl.conn = NULL;
goto authabort;
}
VNC_DEBUG("SASL return data %d bytes, nil; %d\n",
serveroutlen, serverout ? 0 : 1);
if (serveroutlen) {
vnc_write_u32(vs, serveroutlen + 1);
vnc_write(vs, serverout, serveroutlen + 1);
} else {
vnc_write_u32(vs, 0);
}
/* Whether auth is complete */
vnc_write_u8(vs, err == SASL_CONTINUE ? 0 : 1);
if (err == SASL_CONTINUE) {
VNC_DEBUG("%s", "Authentication must continue\n");
/* Wait for step length */
vnc_read_when(vs, protocol_client_auth_sasl_step_len, 4);
} else {
if (!vnc_auth_sasl_check_ssf(vs)) {
VNC_DEBUG("Authentication rejected for weak SSF %p\n", vs->ioc);
goto authreject;
}
/* Check username whitelist ACL */
if (vnc_auth_sasl_check_access(vs) < 0) {
VNC_DEBUG("Authentication rejected for ACL %p\n", vs->ioc);
goto authreject;
}
VNC_DEBUG("Authentication successful %p\n", vs->ioc);
vnc_write_u32(vs, 0); /* Accept auth */
start_client_init(vs);
}
return 0;
authreject:
vnc_write_u32(vs, 1); /* Reject auth */
vnc_write_u32(vs, sizeof("Authentication failed"));
vnc_write(vs, "Authentication failed", sizeof("Authentication failed"));
vnc_flush(vs);
vnc_client_error(vs);
return -1;
authabort:
vnc_client_error(vs);
return -1;
}
int vnc_tls_client_setup(struct VncState *vs,
int needX509Creds) {
VNC_DEBUG("Do TLS setup\n");
if (vnc_tls_initialize() < 0) {
VNC_DEBUG("Failed to init TLS\n");
vnc_client_error(vs);
return -1;
}
if (vs->tls.session == NULL) {
if (gnutls_init(&vs->tls.session, GNUTLS_SERVER) < 0) {
vnc_client_error(vs);
return -1;
}
if (gnutls_set_default_priority(vs->tls.session) < 0) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
vnc_client_error(vs);
return -1;
}
if (vnc_set_gnutls_priority(vs->tls.session, needX509Creds) < 0) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
vnc_client_error(vs);
return -1;
}
if (needX509Creds) {
gnutls_certificate_server_credentials x509_cred = vnc_tls_initialize_x509_cred(vs->vd);
if (!x509_cred) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
vnc_client_error(vs);
return -1;
}
if (gnutls_credentials_set(vs->tls.session, GNUTLS_CRD_CERTIFICATE, x509_cred) < 0) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
gnutls_certificate_free_credentials(x509_cred);
vnc_client_error(vs);
return -1;
}
if (vs->vd->tls.x509verify) {
VNC_DEBUG("Requesting a client certificate\n");
gnutls_certificate_server_set_request (vs->tls.session, GNUTLS_CERT_REQUEST);
}
} else {
gnutls_anon_server_credentials_t anon_cred = vnc_tls_initialize_anon_cred();
if (!anon_cred) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
vnc_client_error(vs);
return -1;
}
if (gnutls_credentials_set(vs->tls.session, GNUTLS_CRD_ANON, anon_cred) < 0) {
gnutls_deinit(vs->tls.session);
vs->tls.session = NULL;
gnutls_anon_free_server_credentials(anon_cred);
vnc_client_error(vs);
return -1;
}
}
gnutls_transport_set_ptr(vs->tls.session, (gnutls_transport_ptr_t)vs);
gnutls_transport_set_push_function(vs->tls.session, vnc_tls_push);
gnutls_transport_set_pull_function(vs->tls.session, vnc_tls_pull);
}
return 0;
}
void start_auth_sasl(VncState *vs)
{
const char *mechlist = NULL;
sasl_security_properties_t secprops;
int err;
char *localAddr, *remoteAddr;
int mechlistlen;
VNC_DEBUG("Initialize SASL auth %p\n", vs->ioc);
/* Get local & remote client addresses in form IPADDR;PORT */
localAddr = vnc_socket_ip_addr_string(vs->sioc, true, NULL);
if (!localAddr) {
goto authabort;
}
remoteAddr = vnc_socket_ip_addr_string(vs->sioc, false, NULL);
if (!remoteAddr) {
g_free(localAddr);
goto authabort;
}
err = sasl_server_new("vnc",
NULL, /* FQDN - just delegates to gethostname */
NULL, /* User realm */
localAddr,
remoteAddr,
NULL, /* Callbacks, not needed */
SASL_SUCCESS_DATA,
&vs->sasl.conn);
g_free(localAddr);
g_free(remoteAddr);
localAddr = remoteAddr = NULL;
if (err != SASL_OK) {
VNC_DEBUG("sasl context setup failed %d (%s)",
err, sasl_errstring(err, NULL, NULL));
vs->sasl.conn = NULL;
goto authabort;
}
/* Inform SASL that we've got an external SSF layer from TLS/x509 */
if (vs->auth == VNC_AUTH_VENCRYPT &&
vs->subauth == VNC_AUTH_VENCRYPT_X509SASL) {
Error *local_err = NULL;
int keysize;
sasl_ssf_t ssf;
keysize = qcrypto_tls_session_get_key_size(vs->tls,
&local_err);
if (keysize < 0) {
VNC_DEBUG("cannot TLS get cipher size: %s\n",
error_get_pretty(local_err));
error_free(local_err);
sasl_dispose(&vs->sasl.conn);
vs->sasl.conn = NULL;
goto authabort;
}
ssf = keysize * CHAR_BIT; /* tls key size is bytes, sasl wants bits */
err = sasl_setprop(vs->sasl.conn, SASL_SSF_EXTERNAL, &ssf);
if (err != SASL_OK) {
VNC_DEBUG("cannot set SASL external SSF %d (%s)\n",
err, sasl_errstring(err, NULL, NULL));
sasl_dispose(&vs->sasl.conn);
vs->sasl.conn = NULL;
goto authabort;
}
} else {
vs->sasl.wantSSF = 1;
}
memset (&secprops, 0, sizeof secprops);
/* Inform SASL that we've got an external SSF layer from TLS.
*
* Disable SSF, if using TLS+x509+SASL only. TLS without x509
* is not sufficiently strong
*/
if (vs->vd->is_unix ||
(vs->auth == VNC_AUTH_VENCRYPT &&
vs->subauth == VNC_AUTH_VENCRYPT_X509SASL)) {
/* If we've got TLS or UNIX domain sock, we don't care about SSF */
secprops.min_ssf = 0;
secprops.max_ssf = 0;
secprops.maxbufsize = 8192;
secprops.security_flags = 0;
} else {
/* Plain TCP, better get an SSF layer */
secprops.min_ssf = 56; /* Good enough to require kerberos */
secprops.max_ssf = 100000; /* Arbitrary big number */
secprops.maxbufsize = 8192;
/* Forbid any anonymous or trivially crackable auth */
secprops.security_flags =
SASL_SEC_NOANONYMOUS | SASL_SEC_NOPLAINTEXT;
}
err = sasl_setprop(vs->sasl.conn, SASL_SEC_PROPS, &secprops);
if (err != SASL_OK) {
VNC_DEBUG("cannot set SASL security props %d (%s)\n",
err, sasl_errstring(err, NULL, NULL));
sasl_dispose(&vs->sasl.conn);
vs->sasl.conn = NULL;
goto authabort;
}
err = sasl_listmech(vs->sasl.conn,
NULL, /* Don't need to set user */
"", /* Prefix */
",", /* Separator */
"", /* Suffix */
&mechlist,
NULL,
NULL);
if (err != SASL_OK) {
VNC_DEBUG("cannot list SASL mechanisms %d (%s)\n",
err, sasl_errdetail(vs->sasl.conn));
sasl_dispose(&vs->sasl.conn);
vs->sasl.conn = NULL;
goto authabort;
}
VNC_DEBUG("Available mechanisms for client: '%s'\n", mechlist);
vs->sasl.mechlist = g_strdup(mechlist);
mechlistlen = strlen(mechlist);
vnc_write_u32(vs, mechlistlen);
vnc_write(vs, mechlist, mechlistlen);
vnc_flush(vs);
VNC_DEBUG("Wait for client mechname length\n");
vnc_read_when(vs, protocol_client_auth_sasl_mechname_len, 4);
return;
authabort:
vnc_client_error(vs);
}