ui: add tracing of VNC authentication process (7364dbda) · Commits · SUMMER2020 / students / proj-2021291

ui/trace-events

+15 −0

Original line number	Diff line number	Diff line
		@@ -35,6 +35,21 @@ vnc_client_connect(void state, void ioc) "VNC client connect state=%p ioc=%p"
		vnc_client_disconnect_start(void state, void ioc) "VNC client disconnect start state=%p ioc=%p"
		vnc_client_disconnect_finish(void state, void ioc) "VNC client disconnect finish state=%p ioc=%p"
		vnc_client_io_wrap(void state, void ioc, const char *type) "VNC client I/O wrap state=%p ioc=%p type=%s"
		vnc_auth_init(void *display, int websock, int auth, int subauth) "VNC auth init state=%p websock=%d auth=%d subauth=%d"
		vnc_auth_start(void *state, int method) "VNC client auth start state=%p method=%d"
		vnc_auth_pass(void *state, int method) "VNC client auth passed state=%p method=%d"
		vnc_auth_fail(void state, int method, const char message, const char *reason) "VNC client auth failed state=%p method=%d message=%s reason=%s"
		vnc_auth_reject(void *state, int expect, int got) "VNC client auth rejected state=%p method expected=%d got=%d"
		vnc_auth_vencrypt_version(void *state, int major, int minor) "VNC client auth vencrypt version state=%p major=%d minor=%d"
		vnc_auth_vencrypt_subauth(void *state, int auth) "VNC client auth vencrypt subauth state=%p auth=%d"
		vnc_auth_sasl_mech_list(void state, const char mechs) "VNC client auth SASL state=%p mechlist=%s"
		vnc_auth_sasl_mech_choose(void state, const char mech) "VNC client auth SASL state=%p mech=%s"
		vnc_auth_sasl_start(void state, const void clientdata, size_t clientlen, const void *serverdata, size_t severlen, int ret) "VNC client auth SASL start state=%p clientdata=%p clientlen=%zu serverdata=%p serverlen=%zu ret=%d"
		vnc_auth_sasl_step(void state, const void clientdata, size_t clientlen, const void *serverdata, size_t severlen, int ret) "VNC client auth SASL step state=%p clientdata=%p clientlen=%zu serverdata=%p serverlen=%zu ret=%d"
		vnc_auth_sasl_ssf(void *state, int ssf) "VNC client auth SASL SSF state=%p size=%d"
		vnc_auth_sasl_username(void state, const char name) "VNC client auth SASL user state=%p name=%s"
		vnc_auth_sasl_acl(void *state, int allow) "VNC client auth SASL ACL state=%p allow=%d"


		# ui/input.c
		input_event_key_number(int conidx, int number, const char *qcode, bool down) "con %d, key number 0x%x [%s], down %d"

ui/vnc-auth-sasl.c

+50 −63

Original line number	Diff line number	Diff line
		@@ -25,6 +25,7 @@
		#include "qemu/osdep.h"
		#include "qapi/error.h"
		#include "vnc.h"
		#include "trace.h"

		/* Max amount of data we send/recv for SASL steps to prevent DOS */
		#define SASL_DATA_MAX_LEN (1024 * 1024)
		@@ -133,27 +134,26 @@ static int vnc_auth_sasl_check_access(VncState *vs)

		err = sasl_getprop(vs->sasl.conn, SASL_USERNAME, &val);
		if (err != SASL_OK) {
		VNC_DEBUG("cannot query SASL username on connection %d (%s), denying access\n",
		err, sasl_errstring(err, NULL, NULL));
		trace_vnc_auth_fail(vs, vs->auth, "Cannot fetch SASL username",
		sasl_errstring(err, NULL, NULL));
		return -1;
		}
		if (val == NULL) {
		VNC_DEBUG("no client username was found, denying access\n");
		trace_vnc_auth_fail(vs, vs->auth, "No SASL username set", "");
		return -1;
		}
		VNC_DEBUG("SASL client username %s\n", (const char *)val);

		vs->sasl.username = g_strdup((const char*)val);
		trace_vnc_auth_sasl_username(vs, vs->sasl.username);

		if (vs->vd->sasl.acl == NULL) {
		VNC_DEBUG("no ACL activated, allowing access\n");
		trace_vnc_auth_sasl_acl(vs, 1);
		return 0;
		}

		allow = qemu_acl_party_is_allowed(vs->vd->sasl.acl, vs->sasl.username);

		VNC_DEBUG("SASL client %s %s by ACL\n", vs->sasl.username,
		allow ? "allowed" : "denied");
		trace_vnc_auth_sasl_acl(vs, allow);
		return allow ? 0 : -1;
		}

		@@ -170,7 +170,9 @@ static int vnc_auth_sasl_check_ssf(VncState *vs)
		return 0;

		ssf = (const int )val;
		VNC_DEBUG("negotiated an SSF of %d\n", ssf);

		trace_vnc_auth_sasl_ssf(vs, ssf);

		if (ssf < 56)
		return 0; /* 56 is good for Kerberos */

		@@ -218,33 +220,28 @@ static int protocol_client_auth_sasl_step(VncState vs, uint8_t data, size_t le
		datalen--; /* Don't count NULL byte when passing to _start() */
		}

		VNC_DEBUG("Step using SASL Data %p (%d bytes)\n",
		clientdata, datalen);
		err = sasl_server_step(vs->sasl.conn,
		clientdata,
		datalen,
		&serverout,
		&serveroutlen);
		trace_vnc_auth_sasl_step(vs, data, len, serverout, serveroutlen, err);
		if (err != SASL_OK &&
		err != SASL_CONTINUE) {
		VNC_DEBUG("sasl step failed %d (%s)\n",
		err, sasl_errdetail(vs->sasl.conn));
		trace_vnc_auth_fail(vs, vs->auth, "Cannot step SASL auth",
		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 step reply data too long %d\n",
		serveroutlen);
		trace_vnc_auth_fail(vs, vs->auth, "SASL data too long", "");
		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);
		@@ -256,22 +253,20 @@ static int protocol_client_auth_sasl_step(VncState vs, uint8_t data, size_t le
		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);
		trace_vnc_auth_fail(vs, vs->auth, "SASL SSF too weak", "");
		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);
		trace_vnc_auth_pass(vs, vs->auth);
		vnc_write_u32(vs, 0); /* Accept auth */
		/*
		* Delay writing in SSF encoded mode until pending output
		@@ -300,9 +295,9 @@ static int protocol_client_auth_sasl_step(VncState vs, uint8_t data, size_t le
		static int protocol_client_auth_sasl_step_len(VncState vs, uint8_t data, size_t len)
		{
		uint32_t steplen = read_u32(data, 0);
		VNC_DEBUG("Got client step len %d\n", steplen);

		if (steplen > SASL_DATA_MAX_LEN) {
		VNC_DEBUG("Too much SASL data %d\n", steplen);
		trace_vnc_auth_fail(vs, vs->auth, "SASL step len too large", "");
		vnc_client_error(vs);
		return -1;
		}
		@@ -346,33 +341,28 @@ static int protocol_client_auth_sasl_start(VncState vs, uint8_t data, size_t l
		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);
		trace_vnc_auth_sasl_start(vs, data, len, serverout, serveroutlen, err);
		if (err != SASL_OK &&
		err != SASL_CONTINUE) {
		VNC_DEBUG("sasl start failed %d (%s)\n",
		err, sasl_errdetail(vs->sasl.conn));
		trace_vnc_auth_fail(vs, vs->auth, "Cannot start SASL auth",
		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);
		trace_vnc_auth_fail(vs, vs->auth, "SASL data too long", "");
		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);
		@@ -384,22 +374,20 @@ static int protocol_client_auth_sasl_start(VncState vs, uint8_t data, size_t l
		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);
		trace_vnc_auth_fail(vs, vs->auth, "SASL SSF too weak", "");
		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);
		trace_vnc_auth_pass(vs, vs->auth);
		vnc_write_u32(vs, 0); /* Accept auth */
		start_client_init(vs);
		}
		@@ -422,9 +410,9 @@ static int protocol_client_auth_sasl_start(VncState vs, uint8_t data, size_t l
		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);
		trace_vnc_auth_fail(vs, vs->auth, "SASL start len too large", "");
		vnc_client_error(vs);
		return -1;
		}
		@@ -439,22 +427,18 @@ static int protocol_client_auth_sasl_start_len(VncState vs, uint8_t data, size
		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);
		trace_vnc_auth_sasl_mech_choose(vs, mechname);

		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] != ',')) {
		@@ -465,11 +449,11 @@ static int protocol_client_auth_sasl_mechname(VncState vs, uint8_t data, size_
		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:
		trace_vnc_auth_fail(vs, vs->auth, "Unsupported mechname", mechname);
		vnc_client_error(vs);
		g_free(mechname);
		return -1;
		@@ -478,14 +462,14 @@ static int protocol_client_auth_sasl_mechname(VncState vs, uint8_t data, size_
		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);
		trace_vnc_auth_fail(vs, vs->auth, "SASL mechname too long", "");
		vnc_client_error(vs);
		return -1;
		}
		if (mechlen < 1) {
		VNC_DEBUG("Too short SASL mechname %d\n", mechlen);
		trace_vnc_auth_fail(vs, vs->auth, "SASL mechname too short", "");
		vnc_client_error(vs);
		return -1;
		}
		@@ -524,19 +508,22 @@ void start_auth_sasl(VncState *vs)
		const char *mechlist = NULL;
		sasl_security_properties_t secprops;
		int err;
		Error *local_err = NULL;
		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);
		localAddr = vnc_socket_ip_addr_string(vs->sioc, true, &local_err);
		if (!localAddr) {
		trace_vnc_auth_fail(vs, vs->auth, "Cannot format local IP",
		error_get_pretty(local_err));
		goto authabort;
		}

		remoteAddr = vnc_socket_ip_addr_string(vs->sioc, false, NULL);
		remoteAddr = vnc_socket_ip_addr_string(vs->sioc, false, &local_err);
		if (!remoteAddr) {
		trace_vnc_auth_fail(vs, vs->auth, "Cannot format remote IP",
		error_get_pretty(local_err));
		g_free(localAddr);
		goto authabort;
		}
		@@ -554,8 +541,8 @@ void start_auth_sasl(VncState *vs)
		localAddr = remoteAddr = NULL;

		if (err != SASL_OK) {
		VNC_DEBUG("sasl context setup failed %d (%s)",
		err, sasl_errstring(err, NULL, NULL));
		trace_vnc_auth_fail(vs, vs->auth, "SASL context setup failed",
		sasl_errstring(err, NULL, NULL));
		vs->sasl.conn = NULL;
		goto authabort;
		}
		@@ -570,7 +557,7 @@ void start_auth_sasl(VncState *vs)
		keysize = qcrypto_tls_session_get_key_size(vs->tls,
		&local_err);
		if (keysize < 0) {
		VNC_DEBUG("cannot TLS get cipher size: %s\n",
		trace_vnc_auth_fail(vs, vs->auth, "cannot TLS get cipher size",
		error_get_pretty(local_err));
		error_free(local_err);
		sasl_dispose(&vs->sasl.conn);
		@@ -581,8 +568,8 @@ void start_auth_sasl(VncState *vs)

		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));
		trace_vnc_auth_fail(vs, vs->auth, "cannot set SASL external SSF",
		sasl_errstring(err, NULL, NULL));
		sasl_dispose(&vs->sasl.conn);
		vs->sasl.conn = NULL;
		goto authabort;
		@@ -617,8 +604,8 @@ void start_auth_sasl(VncState *vs)

		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));
		trace_vnc_auth_fail(vs, vs->auth, "cannot set SASL security props",
		sasl_errstring(err, NULL, NULL));
		sasl_dispose(&vs->sasl.conn);
		vs->sasl.conn = NULL;
		goto authabort;
		@@ -633,13 +620,13 @@ void start_auth_sasl(VncState *vs)
		NULL,
		NULL);
		if (err != SASL_OK) {
		VNC_DEBUG("cannot list SASL mechanisms %d (%s)\n",
		err, sasl_errdetail(vs->sasl.conn));
		trace_vnc_auth_fail(vs, vs->auth, "cannot list SASL mechanisms",
		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);
		trace_vnc_auth_sasl_mech_list(vs, mechlist);

		vs->sasl.mechlist = g_strdup(mechlist);
		mechlistlen = strlen(mechlist);
		@@ -647,12 +634,12 @@ void start_auth_sasl(VncState *vs)
		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:
		error_free(local_err);
		vnc_client_error(vs);
		}

ui/vnc-auth-vencrypt.c

+9 −12

Original line number	Diff line number	Diff line
		@@ -35,27 +35,24 @@ 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);
		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";
		@@ -73,7 +70,7 @@ static void vnc_tls_handshake_done(QIOTask *task,
		Error *err = NULL;

		if (qio_task_propagate_error(task, &err)) {
		VNC_DEBUG("Handshake failed %s\n",
		trace_vnc_auth_fail(vs, vs->auth, "TLS handshake failed",
		error_get_pretty(err));
		vnc_client_error(vs);
		error_free(err);
		@@ -89,15 +86,15 @@ 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) {
		VNC_DEBUG("Rejecting auth %d\n", auth);
		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_DEBUG("Accepting auth %d, setting up TLS for handshake\n", auth);
		vnc_write_u8(vs, 1); /* Accept auth */
		vnc_flush(vs);

		@@ -112,14 +109,14 @@ static int protocol_client_vencrypt_auth(VncState vs, uint8_t data, size_t len
		vs->vd->tlsaclname,
		&err);
		if (!tls) {
		VNC_DEBUG("Failed to setup TLS %s\n", error_get_pretty(err));
		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");
		VNC_DEBUG("Start TLS VeNCrypt handshake process\n");
		object_unref(OBJECT(vs->ioc));
		vs->ioc = QIO_CHANNEL(tls);
		trace_vnc_client_io_wrap(vs, vs->ioc, "tls");
		@@ -135,14 +132,14 @@ static int protocol_client_vencrypt_auth(VncState vs, uint8_t data, size_t len

		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) {
		VNC_DEBUG("Unsupported VeNCrypt protocol %d.%d\n", (int)data[0], (int)data[1]);
		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_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 */

ui/vnc.c

+18 −18

Original line number	Diff line number	Diff line
		@@ -2406,11 +2406,11 @@ static int protocol_client_auth_vnc(VncState vs, uint8_t data, size_t len)
		Error *err = NULL;

		if (!vs->vd->password) {
		VNC_DEBUG("No password configured on server");
		trace_vnc_auth_fail(vs, vs->auth, "password is not set", "");
		goto reject;
		}
		if (vs->vd->expires < now) {
		VNC_DEBUG("Password is expired");
		trace_vnc_auth_fail(vs, vs->auth, "password is expired", "");
		goto reject;
		}

		@@ -2427,7 +2427,7 @@ static int protocol_client_auth_vnc(VncState vs, uint8_t data, size_t len)
		key, G_N_ELEMENTS(key),
		&err);
		if (!cipher) {
		VNC_DEBUG("Cannot initialize cipher %s",
		trace_vnc_auth_fail(vs, vs->auth, "cannot create cipher",
		error_get_pretty(err));
		error_free(err);
		goto reject;
		@@ -2438,7 +2438,7 @@ static int protocol_client_auth_vnc(VncState vs, uint8_t data, size_t len)
		response,
		VNC_AUTH_CHALLENGE_SIZE,
		&err) < 0) {
		VNC_DEBUG("Cannot encrypt challenge %s",
		trace_vnc_auth_fail(vs, vs->auth, "cannot encrypt challenge response",
		error_get_pretty(err));
		error_free(err);
		goto reject;
		@@ -2446,10 +2446,10 @@ static int protocol_client_auth_vnc(VncState vs, uint8_t data, size_t len)

		/* Compare expected vs actual challenge response */
		if (memcmp(response, data, VNC_AUTH_CHALLENGE_SIZE) != 0) {
		VNC_DEBUG("Client challenge response did not match\n");
		trace_vnc_auth_fail(vs, vs->auth, "mis-matched challenge response", "");
		goto reject;
		} else {
		VNC_DEBUG("Accepting VNC challenge response\n");
		trace_vnc_auth_pass(vs, vs->auth);
		vnc_write_u32(vs, 0); /* Accept auth */
		vnc_flush(vs);

		@@ -2488,7 +2488,7 @@ static int protocol_client_auth(VncState vs, uint8_t data, size_t len)
		/* We only advertise 1 auth scheme at a time, so client
		* must pick the one we sent. Verify this */
		if (data[0] != vs->auth) { /* Reject auth */
		VNC_DEBUG("Reject auth %d because it didn't match advertized\n", (int)data[0]);
		trace_vnc_auth_reject(vs, vs->auth, (int)data[0]);
		vnc_write_u32(vs, 1);
		if (vs->minor >= 8) {
		static const char err[] = "Authentication failed";
		@@ -2497,36 +2497,33 @@ static int protocol_client_auth(VncState vs, uint8_t data, size_t len)
		}
		vnc_client_error(vs);
		} else { /* Accept requested auth */
		VNC_DEBUG("Client requested auth %d\n", (int)data[0]);
		trace_vnc_auth_start(vs, vs->auth);
		switch (vs->auth) {
		case VNC_AUTH_NONE:
		VNC_DEBUG("Accept auth none\n");
		if (vs->minor >= 8) {
		vnc_write_u32(vs, 0); /* Accept auth completion */
		vnc_flush(vs);
		}
		trace_vnc_auth_pass(vs, vs->auth);
		start_client_init(vs);
		break;

		case VNC_AUTH_VNC:
		VNC_DEBUG("Start VNC auth\n");
		start_auth_vnc(vs);
		break;

		case VNC_AUTH_VENCRYPT:
		VNC_DEBUG("Accept VeNCrypt auth\n");
		start_auth_vencrypt(vs);
		break;

		#ifdef CONFIG_VNC_SASL
		case VNC_AUTH_SASL:
		VNC_DEBUG("Accept SASL auth\n");
		start_auth_sasl(vs);
		break;
		#endif /* CONFIG_VNC_SASL */

		default: /* Should not be possible, but just in case */
		VNC_DEBUG("Reject auth %d server code bug\n", vs->auth);
		trace_vnc_auth_fail(vs, vs->auth, "Unhandled auth method", "");
		vnc_write_u8(vs, 1);
		if (vs->minor >= 8) {
		static const char err[] = "Authentication failed";
		@@ -2571,10 +2568,11 @@ static int protocol_version(VncState vs, uint8_t version, size_t len)
		vs->minor = 3;

		if (vs->minor == 3) {
		trace_vnc_auth_start(vs, vs->auth);
		if (vs->auth == VNC_AUTH_NONE) {
		VNC_DEBUG("Tell client auth none\n");
		vnc_write_u32(vs, vs->auth);
		vnc_flush(vs);
		trace_vnc_auth_pass(vs, vs->auth);
		start_client_init(vs);
		} else if (vs->auth == VNC_AUTH_VNC) {
		VNC_DEBUG("Tell client VNC auth\n");
		@@ -2582,13 +2580,13 @@ static int protocol_version(VncState vs, uint8_t version, size_t len)
		vnc_flush(vs);
		start_auth_vnc(vs);
		} else {
		VNC_DEBUG("Unsupported auth %d for protocol 3.3\n", vs->auth);
		trace_vnc_auth_fail(vs, vs->auth,
		"Unsupported auth method for v3.3", "");
		vnc_write_u32(vs, VNC_AUTH_INVALID);
		vnc_flush(vs);
		vnc_client_error(vs);
		}
		} else {
		VNC_DEBUG("Telling client we support auth %d\n", vs->auth);
		vnc_write_u8(vs, 1); /* num auth */
		vnc_write_u8(vs, vs->auth);
		vnc_read_when(vs, protocol_client_auth, 1);
		@@ -3942,12 +3940,14 @@ void vnc_display_open(const char id, Error *errp)
		sasl, false, errp) < 0) {
		goto fail;
		}
		trace_vnc_auth_init(vd, 0, vd->auth, vd->subauth);

		if (vnc_display_setup_auth(&vd->ws_auth, &vd->ws_subauth,
		vd->tlscreds, password,
		sasl, true, errp) < 0) {
		goto fail;
		}
		trace_vnc_auth_init(vd, 1, vd->ws_auth, vd->ws_subauth);

		#ifdef CONFIG_VNC_SASL
		if ((saslErr = sasl_server_init(NULL, "qemu")) != SASL_OK) {