X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=libudev%2Flibudev-ctrl.c;h=e0ec2fa3d7bcc69e1093b4595fad15844cba8144;hb=b20fd3cb3423676a86f12189126b012d2297d5f7;hp=cea1b7f55b0d359a4bfa62916d23e0a028abd6de;hpb=ff2c503df091e6e4e9ab48cdb6df6ec8b7b525d0;p=elogind.git

diff --git a/libudev/libudev-ctrl.c b/libudev/libudev-ctrl.c
index cea1b7f55..e0ec2fa3d 100644
--- a/libudev/libudev-ctrl.c
+++ b/libudev/libudev-ctrl.c
@@ -60,6 +60,7 @@ struct udev_ctrl {
 	int sock;
 	struct sockaddr_un saddr;
 	socklen_t addrlen;
+	bool bound;
 	bool connected;
 };
 
@@ -81,7 +82,7 @@ static struct udev_ctrl *udev_ctrl_new(struct udev *udev)
 	return uctrl;
 }
 
-struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socket_path)
+struct udev_ctrl *udev_ctrl_new_from_socket_fd(struct udev *udev, const char *socket_path, int fd)
 {
 	struct udev_ctrl *uctrl;
 
@@ -89,11 +90,16 @@ struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socke
 	if (uctrl == NULL)
 		return NULL;
 
-	uctrl->sock = socket(AF_LOCAL, SOCK_SEQPACKET, 0);
-	if (uctrl->sock < 0) {
-		err(udev, "error getting socket: %m\n");
-		udev_ctrl_unref(uctrl);
-		return NULL;
+	if (fd < 0) {
+		uctrl->sock = socket(AF_LOCAL, SOCK_SEQPACKET|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
+		if (uctrl->sock < 0) {
+			err(udev, "error getting socket: %m\n");
+			udev_ctrl_unref(uctrl);
+			return NULL;
+		}
+	} else {
+		uctrl->bound = true;
+		uctrl->sock = fd;
 	}
 
 	uctrl->saddr.sun_family = AF_LOCAL;
@@ -105,35 +111,31 @@ struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socke
 	return uctrl;
 }
 
-struct udev_ctrl *udev_ctrl_new_from_fd(struct udev *udev, int fd)
+struct udev_ctrl *udev_ctrl_new_from_socket(struct udev *udev, const char *socket_path)
 {
-	struct udev_ctrl *uctrl;
-
-	uctrl = udev_ctrl_new(udev);
-	if (uctrl == NULL)
-		return NULL;
-	uctrl->sock = fd;
-
-	return uctrl;
+	return udev_ctrl_new_from_socket_fd(udev, socket_path, -1);
 }
 
 int udev_ctrl_enable_receiving(struct udev_ctrl *uctrl)
 {
 	int err;
 
-	if (uctrl->addrlen > 0) {
+	if (!uctrl->bound) {
 		err = bind(uctrl->sock, (struct sockaddr *)&uctrl->saddr, uctrl->addrlen);
 		if (err < 0) {
 			err = -errno;
 			err(uctrl->udev, "bind failed: %m\n");
 			return err;
 		}
+
 		err = listen(uctrl->sock, 0);
 		if (err < 0) {
 			err = -errno;
 			err(uctrl->udev, "listen failed: %m\n");
 			return err;
 		}
+
+		uctrl->bound = true;
 	}
 	return 0;
 }
@@ -174,6 +176,8 @@ int udev_ctrl_get_fd(struct udev_ctrl *uctrl)
 struct udev_ctrl_connection *udev_ctrl_get_connection(struct udev_ctrl *uctrl)
 {
 	struct udev_ctrl_connection *conn;
+	struct ucred ucred;
+	socklen_t slen;
 	const int on = 1;
 
 	conn = calloc(1, sizeof(struct udev_ctrl_connection));
@@ -182,16 +186,33 @@ struct udev_ctrl_connection *udev_ctrl_get_connection(struct udev_ctrl *uctrl)
 	conn->refcount = 1;
 	conn->uctrl = uctrl;
 
-	conn->sock = accept4(uctrl->sock, NULL, NULL, SOCK_CLOEXEC);
+	conn->sock = accept4(uctrl->sock, NULL, NULL, SOCK_CLOEXEC|SOCK_NONBLOCK);
 	if (conn->sock < 0) {
-		free(conn);
-		return NULL;
+		if (errno != EINTR)
+			err(uctrl->udev, "unable to receive ctrl connection: %m\n");
+		goto err;
+	}
+
+	/* check peer credential of connection */
+	slen = sizeof(ucred);
+	if (getsockopt(conn->sock, SOL_SOCKET, SO_PEERCRED, &ucred, &slen) < 0) {
+		err(uctrl->udev, "unable to receive credentials of ctrl connection: %m\n");
+		goto err;
+	}
+	if (ucred.uid > 0) {
+		err(uctrl->udev, "sender uid=%i, message ignored\n", ucred.uid);
+		goto err;
 	}
 
-	/* enable receiving of the sender credentials */
+	/* enable receiving of the sender credentials in the messages */
 	setsockopt(conn->sock, SOL_SOCKET, SO_PASSCRED, &on, sizeof(on));
 	udev_ctrl_ref(uctrl);
 	return conn;
+err:
+	if (conn->sock >= 0)
+		close(conn->sock);
+	free(conn);
+	return NULL;
 }
 
 struct udev_ctrl_connection *udev_ctrl_connection_ref(struct udev_ctrl_connection *conn)
@@ -327,19 +348,44 @@ struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn)
 		return NULL;
 	uctrl_msg->refcount = 1;
 	uctrl_msg->conn = conn;
+	udev_ctrl_connection_ref(conn);
+
+	/* wait for the incoming message */
+	for(;;) {
+		struct pollfd pfd[1];
+		int r;
+
+		pfd[0].fd = conn->sock;
+		pfd[0].events = POLLIN;
+
+		r = poll(pfd, 1, 10000);
+		if (r  < 0) {
+			if (errno == EINTR)
+				continue;
+			goto err;
+		} else if (r == 0) {
+			err(udev, "timeout waiting for ctrl message\n");
+			goto err;
+		} else {
+			if (!(pfd[0].revents & POLLIN)) {
+				err(udev, "ctrl connection error: %m\n");
+				goto err;
+			}
+		}
+
+		break;
+	}
 
 	iov.iov_base = &uctrl_msg->ctrl_msg_wire;
 	iov.iov_len = sizeof(struct udev_ctrl_msg_wire);
-
 	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);
-
 	size = recvmsg(conn->sock, &smsg, 0);
 	if (size <  0) {
-		err(udev, "unable to receive user udevd message: %m\n");
+		err(udev, "unable to receive ctrl message: %m\n");
 		goto err;
 	}
 	cmsg = CMSG_FIRSTHDR(&smsg);
@@ -361,7 +407,6 @@ struct udev_ctrl_msg *udev_ctrl_receive_msg(struct udev_ctrl_connection *conn)
 	}
 
 	dbg(udev, "created ctrl_msg %p (%i)\n", uctrl_msg, uctrl_msg->ctrl_msg_wire.type);
-	udev_ctrl_connection_ref(conn);
 	return uctrl_msg;
 err:
 	udev_ctrl_msg_unref(uctrl_msg);