device: sanitze UTF-8 values for D-Bus

ip link add name $'d\xccf\\c' type dummy

Use nm_utils_str_utf8safe_escape() to sanitize non UTF-8 sequences
before exposing them on D-Bus. The operation can be reverted client
side via nm_utils_str_utf8safe_unescape() or simply g_strcompress().

Note that this preserves all valid UTF-8 sequences as-is, with exception
of the backslash escape character and ASCII control characters. Thus, this
is a change in behavior for strings that contain such characters.

Note that nmcli is not changed to somehow unescape the string before
printing. As the string is not valid UTF-8 (or contains ASCII characters
that need escaping), they are not printable as-is, so unescaping before
printing makes little sense.

introspection/org.freedesktop.NetworkManager.Device.xml

@@ -21,6 +21,9 @@
         each device in your application, use the object path. If you're looking
         for a way to track a specific piece of hardware across reboot or hotplug,
         use a MAC address or USB serial number.
+
+        Note that non-UTF-8 characters are backslash escaped. Use g_strcompress()
+        to obtain the true (non-UTF-8) string.
     -->
     <property name="Udi" type="s" access="read"/>
 
@@ -28,6 +31,9 @@
         Interface:
 
         The name of the device's control (and often data) interface.
+        Note that non UTF-8 characters are backslash escaped, so the
+        resulting name may be longer then 15 characters. Use g_strcompress()
+        to revert the escaping.
     -->
     <property name="Interface" type="s" access="read"/>
 
@@ -38,6 +44,9 @@
         not refer to the actual data interface until the device has successfully
         established a data connection, indicated by the device's State becoming
         ACTIVATED.
+        Note that non UTF-8 characters are backslash escaped, so the
+        resulting name may be longer then 15 characters. Use g_strcompress()
+        to revert the escaping.
     -->
     <property name="IpInterface" type="s" access="read"/>
 
@@ -45,6 +54,8 @@
         Driver:
 
         The driver handling the device.
+        Non-UTF-8 sequences are backslash escaped. Use g_strcompress()
+        to revert.
     -->
     <property name="Driver" type="s" access="read"/>
 
@@ -52,6 +63,8 @@
         DriverVersion:
 
         The version of the driver handling the device.
+        Non-UTF-8 sequences are backslash escaped. Use g_strcompress()
+        to revert.
     -->
     <property name="DriverVersion" type="s" access="read"/>
 
@@ -59,6 +72,8 @@
         FirmwareVersion:
 
         The firmware version for the device.
+        Non-UTF-8 sequences are backslash escaped. Use g_strcompress()
+        to revert.
     -->
     <property name="FirmwareVersion" type="s" access="read"/>
 

src/devices/nm-device.c

@@ -13938,28 +13938,43 @@ get_property (GObject *object, guint prop_id,
 
 	switch (prop_id) {
 	case PROP_UDI:
-		g_value_set_string (value, priv->udi);
+		/* UDI is (depending on the device type) a path to sysfs and can contain
+		 * non-UTF-8.
+		 *   ip link add name $'d\xccf\\c' type dummy  */
+		g_value_take_string (value,
+		                     nm_utils_str_utf8safe_escape_cp (priv->udi,
+		                                                      NM_UTILS_STR_UTF8_SAFE_FLAG_NONE));
 		break;
 	case PROP_IFACE:
-		g_value_set_string (value, priv->iface);
+		g_value_take_string (value,
+		                     nm_utils_str_utf8safe_escape_cp (priv->iface,
+		                                                      NM_UTILS_STR_UTF8_SAFE_FLAG_ESCAPE_CTRL));
 		break;
 	case PROP_IP_IFACE:
-		if (ip_config_valid (priv->state))
-			g_value_set_string (value, nm_device_get_ip_iface (self));
-		else
+		if (ip_config_valid (priv->state)) {
+			g_value_take_string (value,
+			                     nm_utils_str_utf8safe_escape_cp (nm_device_get_ip_iface (self),
+			                                                      NM_UTILS_STR_UTF8_SAFE_FLAG_ESCAPE_CTRL));
+		} else
 			g_value_set_string (value, NULL);
 		break;
 	case PROP_IFINDEX:
 		g_value_set_int (value, priv->ifindex);
 		break;
 	case PROP_DRIVER:
-		g_value_set_string (value, priv->driver);
+		g_value_take_string (value,
+		                     nm_utils_str_utf8safe_escape_cp (priv->driver,
+		                                                      NM_UTILS_STR_UTF8_SAFE_FLAG_ESCAPE_CTRL));
 		break;
 	case PROP_DRIVER_VERSION:
-		g_value_set_string (value, priv->driver_version);
+		g_value_take_string (value,
+		                     nm_utils_str_utf8safe_escape_cp (priv->driver_version,
+		                                                      NM_UTILS_STR_UTF8_SAFE_FLAG_ESCAPE_CTRL));
 		break;
 	case PROP_FIRMWARE_VERSION:
-		g_value_set_string (value, priv->firmware_version);
+		g_value_take_string (value,
+		                     nm_utils_str_utf8safe_escape_cp (priv->firmware_version,
+		                                                      NM_UTILS_STR_UTF8_SAFE_FLAG_ESCAPE_CTRL));
 		break;
 	case PROP_CAPABILITIES:
 		g_value_set_uint (value, (priv->capabilities & ~NM_DEVICE_CAP_INTERNAL_MASK));