nl80211: fix wpa supplicant ctrl socket permissions

[project/iwinfo.git] / iwinfo_nl80211.c

diff --git a/iwinfo_nl80211.c b/iwinfo_nl80211.c
index f852ed1c5141827ff8978910f29d3e6d42d1e658..aceef18230ffd9e419dd1ddaf4ff758004eb9390 100644 (file)
--- a/iwinfo_nl80211.c
+++ b/iwinfo_nl80211.c
@@ -938,6 +938,18 @@ static int nl80211_wpactl_connect(const char *ifname, struct sockaddr_un *local)
                sprintf(remote.sun_path, "/var/run/wpa_supplicant-%s/%s",
                        ifname, ifname);
 
+       /* Set client socket file permissions so that bind() creates the client
+       * socket with these permissions and there is no need to try to change
+       * them with chmod() after bind() which would have potential issues with
+       * race conditions. These permissions are needed to make sure the server
+       * side (wpa_supplicant or hostapd) can reply to the control interface
+       * messages.
+       *
+       * The lchown() calls below after bind() are also part of the needed
+       * operations to allow the response to go through. Those are using the
+       * no-deference-symlinks version to avoid races. */
+       fchmod(sock, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
+
        if (fcntl(sock, F_SETFD, fcntl(sock, F_GETFD) | FD_CLOEXEC) < 0)
        {
                close(sock);
@@ -966,6 +978,10 @@ static int nl80211_wpactl_connect(const char *ifname, struct sockaddr_un *local)
                return -1;
        }
 
+       /* Set group even if we do not have privileges to change owner */
+       lchown(local->sun_path, -1, 101);
+       lchown(local->sun_path, 101, 101);
+
        return sock;
 }