Android: Avoid same per-iface and global ctrl socket

Android platform assigns the same socket id if the socket identifier in
conf->ctrl_interface and global->params.ctrl_interface (parameter for
android_get_control_socket) point to the same Android specific control
socket. This ends up having two eloop socket handlers registered for the
same file descriptor and thus, two attempt to receive and process each
command. This can result in unexpected failure, e.g., the prefix IFNAME=
for any command is valid for global socket handler, but results in
UNKNOWN COMMAND response from the per-interface ctrl socket handler).

Since it might be possible to end up with this type of invalid
configuration in OTA upgrade, compare the socket identifiers and do not
open the ctrl socket on the respective interface if both point to same.
This allows the Wi-Fi framework to use the global control interface.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>

wpa_supplicant/ctrl_iface_unix.c

@@ -584,6 +584,53 @@ wpa_supplicant_ctrl_iface_init(struct wpa_supplicant *wpa_s)
 	if (wpa_s->conf->ctrl_interface == NULL)
 		return priv;
 
+#ifdef ANDROID
+	if (wpa_s->global->params.ctrl_interface) {
+		int same = 0;
+
+		if (wpa_s->global->params.ctrl_interface[0] == '/') {
+			if (os_strcmp(wpa_s->global->params.ctrl_interface,
+				      wpa_s->conf->ctrl_interface) == 0)
+				same = 1;
+		} else if (os_strncmp(wpa_s->global->params.ctrl_interface,
+				      "@android:", 9) == 0 ||
+			   os_strncmp(wpa_s->global->params.ctrl_interface,
+				      "@abstract:", 10) == 0) {
+			char *pos;
+
+			/*
+			 * Currently, Android uses @android:wpa_* as the naming
+			 * convention for the global ctrl interface. This logic
+			 * needs to be revisited if the above naming convention
+			 * is modified.
+			 */
+			pos = os_strchr(wpa_s->global->params.ctrl_interface,
+					'_');
+			if (pos &&
+			    os_strcmp(pos + 1,
+				      wpa_s->conf->ctrl_interface) == 0)
+				same = 1;
+		}
+
+		if (same) {
+			/*
+			 * The invalid configuration combination might be
+			 * possible to hit in an Android OTA upgrade case, so
+			 * instead of refusing to start the wpa_supplicant
+			 * process, do not open the per-interface ctrl_iface
+			 * and continue with the global control interface that
+			 * was set from the command line since the Wi-Fi
+			 * framework will use it for operations.
+			 */
+			wpa_printf(MSG_ERROR,
+				   "global ctrl interface %s matches ctrl interface %s - do not open per-interface ctrl interface",
+				   wpa_s->global->params.ctrl_interface,
+				   wpa_s->conf->ctrl_interface);
+			return priv;
+		}
+	}
+#endif /* ANDROID */
+
 	if (wpas_ctrl_iface_open_sock(wpa_s, priv) < 0) {
 		os_free(priv);
 		return NULL;