dhcp: kill dhclient on fatal errors

This helps to avoid dhclient DOSing the network.

https://bugzilla.gnome.org/show_bug.cgi?id=705137

1 files changed, 22 insertions, 4 deletions

diff --git a/src/dhcp-manager/nm-dhcp-helper.c b/src/dhcp-manager/nm-dhcp-helper.c
index 7b510d7a9c..4ddfafe173 100644
--- a/src/dhcp-manager/nm-dhcp-helper.c
+++ b/src/dhcp-manager/nm-dhcp-helper.c
@@ -25,6 +25,8 @@
 #include <unistd.h>
 #include <stdlib.h>
 #include <string.h>
+#include <signal.h>
+
 #include <config.h>
 
 #include <dbus/dbus.h>
@@ -273,6 +275,22 @@ error:
 }
 #endif
 
+static void
+fatal_error (void)
+{
+	const char *pid_str = getenv ("pid");
+	int pid = 0;
+
+	if (pid_str)
+		pid = strtol (pid_str, NULL, 10);
+	if (pid) {
+		fprintf (stderr, "Fatal error occured, killing dhclient instance with pid %d.\n", pid);
+		kill (pid, SIGTERM);
+	}
+
+	exit (1);
+}
+
 int
 main (int argc, char *argv[])
 {
@@ -293,7 +311,7 @@ main (int argc, char *argv[])
 			fprintf (stderr, "Error: could not connect to NetworkManager DBus socket: (%s) %s\n",
 				     error.name, error.message);
 			dbus_error_free (&error);
-			exit (1);
+			fatal_error ();
 		}
 	}
 	dbus_connection_set_exit_on_disconnect (connection, FALSE);
@@ -301,21 +319,21 @@ main (int argc, char *argv[])
 	message = dbus_message_new_signal ("/", NM_DHCP_CLIENT_DBUS_IFACE, "Event");
 	if (message == NULL) {
 		fprintf (stderr, "Error: Not enough memory to send DHCP Event signal.\n");
-		exit (1);
+		fatal_error ();
 	}
 
 	/* Dump environment variables into the message */
 	result = build_message (message);
 	if (result == FALSE) {
 		fprintf (stderr, "Error: Not enough memory to send DHCP Event signal.\n");
-		exit (1);
+		fatal_error ();
 	}
 
 	/* queue the message */
 	result = dbus_connection_send (connection, message, NULL);
 	if (!result) {
 		fprintf (stderr, "Error: Could not send send DHCP Event signal.\n");
-		exit (1);
+		fatal_error ();
 	}
 	dbus_message_unref (message);