X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=udevd.c;h=efcb65bb53f3d78da04a723d213f90e0e3332fd9;hp=8ba833186e100bb3958acb0d0c6b2ff6e81beae1;hb=49f9acf3844aa5c004b5794e919bd54166e53227;hpb=2f6cbd19113167746dc4fb6b4f3f5fd64a1c211f

diff --git a/udevd.c b/udevd.c
index 8ba833186..efcb65bb5 100644
--- a/udevd.c
+++ b/udevd.c
@@ -40,7 +40,6 @@
 #include "udevd.h"
 #include "logging.h"
 
-unsigned char logname[42];
 static int expected_seqnum = 0;
 volatile static int children_waiting;
 volatile static int msg_q_timeout;
@@ -52,6 +51,18 @@ LIST_HEAD(running_list);
 static void exec_queue_manager(void);
 static void msg_queue_manager(void);
 
+#ifdef LOG
+unsigned char logname[LOGNAME_SIZE];
+void log_message (int level, const char *format, ...)
+{
+	va_list	args;
+
+	va_start(args, format);
+	vsyslog(level, format, args);
+	va_end(args);
+}
+#endif
+
 static void msg_dump_queue(void)
 {
 	struct hotplug_msg *msg;
@@ -108,14 +119,18 @@ static void msg_queue_insert(struct hotplug_msg *msg)
 static void udev_run(struct hotplug_msg *msg)
 {
 	pid_t pid;
-	setenv("ACTION", msg->action, 1);
-	setenv("DEVPATH", msg->devpath, 1);
+	char action[ACTION_SIZE];
+	char devpath[DEVPATH_SIZE];
+	char *env[] = { action, devpath, NULL };
+
+	snprintf(action, sizeof(action), "ACTION=%s", msg->action);
+	snprintf(devpath, sizeof(devpath), "DEVPATH=%s", msg->devpath);
 
 	pid = fork();
 	switch (pid) {
 	case 0:
 		/* child */
-		execl(UDEV_BIN, "udev", msg->subsystem, NULL);
+		execle(UDEV_BIN, "udev", msg->subsystem, NULL, env);
 		dbg("exec of child failed");
 		exit(1);
 		break;
@@ -212,6 +227,11 @@ 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) {
@@ -219,17 +239,37 @@ 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 (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);
+		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 */
@@ -239,6 +279,11 @@ static void handle_msg(int sock)
 	} else {
 		msg_queue_insert(msg);
 	}
+	return;
+
+skip:
+	free(msg);
+	return;
 }
 
 static void sig_handler(int signum)
@@ -279,17 +324,28 @@ 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");
+	dbg("version %s", UDEV_VERSION);
 
-	signal(SIGINT, sig_handler);
-	signal(SIGTERM, sig_handler);
-	signal(SIGALRM, sig_handler);
-	signal(SIGCHLD, sig_handler);
+	if (getuid() != 0) {
+		dbg("need to be root, exit");
+		exit(1);
+	}
+
+	/* set signal handler */
+	act.sa_handler = sig_handler;
+	sigemptyset (&act.sa_mask);
+	act.sa_flags = SA_RESTART;
+	sigaction(SIGINT, &act, NULL);
+	sigaction(SIGTERM, &act, NULL);
 
 	/* we want these two to interrupt system calls */
-	siginterrupt(SIGALRM, 1);
-	siginterrupt(SIGCHLD, 1);
+	act.sa_flags = 0;
+	sigaction(SIGALRM, &act, NULL);
+	sigaction(SIGCHLD, &act, NULL);
 
 	memset(&saddr, 0x00, sizeof(saddr));
 	saddr.sun_family = AF_LOCAL;
@@ -299,17 +355,20 @@ 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, &saddr, addrlen);
+	retval = bind(ssock, (struct sockaddr *) &saddr, addrlen);
 	if (retval < 0) {
-		dbg("bind failed\n");
+		dbg("bind failed, exit");
 		goto exit;
 	}
 
+	/* enable receiving of the sender credentials */
+	setsockopt(ssock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
+
 	while (1) {
 		handle_msg(ssock);