[PATCH] better credential patch

[elogind.git] / udevd.c

diff --git a/udevd.c b/udevd.c
index 366c227a3bc9c48c42d1236c4e2fe5006e3cc685..14616b9824e16dd509f74ce00c0996b2624c0119 100644 (file)
--- a/udevd.c
+++ b/udevd.c
@@ -252,16 +252,19 @@ static void handle_msg(int sock)
        cmsg = CMSG_FIRSTHDR(&smsg);
        cred = (struct ucred *) CMSG_DATA(cmsg);
 
+       if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) {
+               dbg("no sender credentials received, message ignored");
+               goto skip;
+       }
+
        if (cred->uid != 0) {
                dbg("sender uid=%i, message ignored", cred->uid);
-               free(msg);
-               return;
+               goto skip;
        }
 
        if (strncmp(msg->magic, UDEV_MAGIC, sizeof(UDEV_MAGIC)) != 0 ) {
                dbg("message magic '%s' doesn't match, ignore it", msg->magic);
-               free(msg);
-               return;
+               goto skip;
        }
 
        /* if no seqnum is given, we move straight to exec queue */
@@ -271,6 +274,11 @@ static void handle_msg(int sock)
        } else {
                msg_queue_insert(msg);
        }
+       return;
+
+skip:
+       free(msg);
+       return;
 }
 
 static void sig_handler(int signum)
@@ -316,6 +324,11 @@ int main(int argc, char *argv[])
 
        init_logging("udevd");
 
+       if (getuid() != 0) {
+               dbg("need to be root, exit");
+               exit(1);
+       }
+
        /* set signal handler */
        act.sa_handler = sig_handler;
        sigemptyset (&act.sa_mask);
@@ -336,14 +349,14 @@ int main(int argc, char *argv[])
 
        ssock = socket(AF_LOCAL, SOCK_DGRAM, 0);
        if (ssock == -1) {
-               dbg("error getting socket");
+               dbg("error getting socket, exit");
                exit(1);
        }
 
        /* the bind takes care of ensuring only one copy running */
        retval = bind(ssock, (struct sockaddr *) &saddr, addrlen);
        if (retval < 0) {
-               dbg("bind failed\n");
+               dbg("bind failed, exit");
                goto exit;
        }