[PATCH] udevd - client access authorization

[elogind.git] / udevd.c

diff --git a/udevd.c b/udevd.c
index 104cb2b9877c92894190b7de93cc6e40637b7e5c..366c227a3bc9c48c42d1236c4e2fe5006e3cc685 100644 (file)
--- a/udevd.c
+++ b/udevd.c
@@ -222,6 +222,11 @@ static void handle_msg(int sock)
 {
        struct hotplug_msg *msg;
        int retval;
+       struct msghdr smsg;
+       struct cmsghdr *cmsg;
+       struct iovec iov;
+       struct ucred *cred;
+       char cred_msg[CMSG_SPACE(sizeof(struct ucred))];
 
        msg = msg_create();
        if (msg == NULL) {
@@ -229,13 +234,30 @@ static void handle_msg(int sock)
                return;
        }
 
-       retval = recv(sock, msg, sizeof(struct hotplug_msg), 0);
+       iov.iov_base = msg;
+       iov.iov_len = sizeof(struct hotplug_msg);
+
+       memset(&smsg, 0x00, sizeof(struct msghdr));
+       smsg.msg_iov = &iov;
+       smsg.msg_iovlen = 1;
+       smsg.msg_control = cred_msg;
+       smsg.msg_controllen = sizeof(cred_msg);
+
+       retval = recvmsg(sock, &smsg, 0);
        if (retval <  0) {
                if (errno != EINTR)
                        dbg("unable to receive message");
                return;
        }
-       
+       cmsg = CMSG_FIRSTHDR(&smsg);
+       cred = (struct ucred *) CMSG_DATA(cmsg);
+
+       if (cred->uid != 0) {
+               dbg("sender uid=%i, message ignored", cred->uid);
+               free(msg);
+               return;
+       }
+
        if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
                dbg("message magic '%s' doesn't match, ignore it", msg->magic);
                free(msg);
@@ -289,6 +311,7 @@ int main(int argc, char *argv[])
        struct sockaddr_un saddr;
        socklen_t addrlen;
        int retval;
+       const int on = 1;
        struct sigaction act;
 
        init_logging("udevd");
@@ -324,6 +347,9 @@ int main(int argc, char *argv[])
                goto exit;
        }
 
+       /* enable receiving of the sender credentials */
+       setsockopt(ssock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
+
        while (1) {
                handle_msg(ssock);