Fix UNIX domain socket address handling to be more portable

Removing just sun_family is not portable since some systems (e.g.,
FreeBSD) include an additional sun_len field. Using offsetof should be
portable. In addition, set sun_ken for FreeBSD.

wpa_supplicant/ctrl_iface_unix.c

@@ -16,6 +16,7 @@
 #include <sys/un.h>
 #include <sys/stat.h>
 #include <grp.h>
+#include <stddef.h>
 
 #include "common.h"
 #include "eloop.h"
@@ -69,7 +70,8 @@ static int wpa_supplicant_ctrl_iface_attach(struct ctrl_iface_priv *priv,
 	dst->next = priv->ctrl_dst;
 	priv->ctrl_dst = dst;
 	wpa_hexdump(MSG_DEBUG, "CTRL_IFACE monitor attached",
-		    (u8 *) from->sun_path, fromlen - sizeof(from->sun_family));
+		    (u8 *) from->sun_path,
+		    fromlen - offsetof(struct sockaddr_un, sun_path));
 	return 0;
 }
 
@@ -84,7 +86,8 @@ static int wpa_supplicant_ctrl_iface_detach(struct ctrl_iface_priv *priv,
 	while (dst) {
 		if (fromlen == dst->addrlen &&
 		    os_memcmp(from->sun_path, dst->addr.sun_path,
-			      fromlen - sizeof(from->sun_family)) == 0) {
+			      fromlen - offsetof(struct sockaddr_un, sun_path))
+		    == 0) {
 			if (prev == NULL)
 				priv->ctrl_dst = dst->next;
 			else
@@ -92,7 +95,8 @@ static int wpa_supplicant_ctrl_iface_detach(struct ctrl_iface_priv *priv,
 			os_free(dst);
 			wpa_hexdump(MSG_DEBUG, "CTRL_IFACE monitor detached",
 				    (u8 *) from->sun_path,
-				    fromlen - sizeof(from->sun_family));
+				    fromlen -
+				    offsetof(struct sockaddr_un, sun_path));
 			return 0;
 		}
 		prev = dst;
@@ -115,10 +119,12 @@ static int wpa_supplicant_ctrl_iface_level(struct ctrl_iface_priv *priv,
 	while (dst) {
 		if (fromlen == dst->addrlen &&
 		    os_memcmp(from->sun_path, dst->addr.sun_path,
-			      fromlen - sizeof(from->sun_family)) == 0) {
+			      fromlen - offsetof(struct sockaddr_un, sun_path))
+		    == 0) {
 			wpa_hexdump(MSG_DEBUG, "CTRL_IFACE changed monitor "
 				    "level", (u8 *) from->sun_path,
-				    fromlen - sizeof(from->sun_family));
+				    fromlen -
+				    offsetof(struct sockaddr_un, sun_path));
 			dst->debug_level = atoi(level);
 			return 0;
 		}
@@ -339,6 +345,9 @@ wpa_supplicant_ctrl_iface_init(struct wpa_supplicant *wpa_s)
 	}
 
 	os_memset(&addr, 0, sizeof(addr));
+#ifdef __FreeBSD__
+	addr.sun_len = sizeof(addr);
+#endif /* __FreeBSD__ */
 	addr.sun_family = AF_UNIX;
 	fname = wpa_supplicant_ctrl_iface_path(wpa_s);
 	if (fname == NULL)
@@ -510,7 +519,7 @@ static void wpa_supplicant_ctrl_iface_send(struct ctrl_iface_priv *priv,
 		if (level >= dst->debug_level) {
 			wpa_hexdump(MSG_DEBUG, "CTRL_IFACE monitor send",
 				    (u8 *) dst->addr.sun_path, dst->addrlen -
-				    sizeof(dst->addr.sun_family));
+				    offsetof(struct sockaddr_un, sun_path));
 			msg.msg_name = (void *) &dst->addr;
 			msg.msg_namelen = dst->addrlen;
 			if (sendmsg(priv->sock, &msg, 0) < 0) {
@@ -640,6 +649,9 @@ wpa_supplicant_global_ctrl_iface_init(struct wpa_global *global)
 	}
 
 	os_memset(&addr, 0, sizeof(addr));
+#ifdef __FreeBSD__
+	addr.sun_len = sizeof(addr);
+#endif /* __FreeBSD__ */
 	addr.sun_family = AF_UNIX;
 	os_strlcpy(addr.sun_path, global->params.ctrl_interface,
 		   sizeof(addr.sun_path));