MFp4 @229484:

Limit routing socket so only poll(2) and read(2) are allowed (CAP_POLL_EVENT
and CAP_READ). This prevents unprivileged process from adding, removing or
modifying system routes.

Reviewed by:	brooks
Sponsored by:	The FreeBSD Foundation

1 files changed, 4 insertions, 0 deletions

diff --git a/sbin/dhclient/dhclient.c b/sbin/dhclient/dhclient.c
index ad0d02e..34ff853 100644
--- a/sbin/dhclient/dhclient.c
+++ b/sbin/dhclient/dhclient.c
@@ -492,6 +492,10 @@ main(int argc, char *argv[])
 		add_protocol("AF_ROUTE", routefd, routehandler, ifi);
 	if (shutdown(routefd, SHUT_WR) < 0)
 		error("can't shutdown route socket: %m");
+	if (cap_rights_limit(routefd, CAP_POLL_EVENT | CAP_READ) < 0 &&
+	    errno != ENOSYS) {
+		error("can't limit route socket: %m");
+	}
 
 	if (chroot(_PATH_VAREMPTY) == -1)
 		error("chroot");