From 3a82f8be03b07b84fa470c6e42cd87865aeaf701 Mon Sep 17 00:00:00 2001 From: Will Woods Date: Fri, 13 Mar 2015 17:24:46 -0400 Subject: [PATCH] selinux: fix SEGV during switch-root if SELinux policy loaded If you've got SELinux policy loaded, label_hnd is your labeling handle. When systemd is shutting down, we free that handle via mac_selinux_finish(). But: switch_root() calls mkdir_p_label(), which tries to look up a label using that freed handle, and so we get a bunch of garbage and eventually SEGV in libselinux. (This doesn't happen in the switch-root from initramfs to real root because there's no SELinux policy loaded in initramfs, so label_hnd is NULL and we never attempt any lookups.) So: make sure that mac_selinux_finish() actually sets label_hnd to NULL, so nobody tries to use it after it becomes invalid. https://bugzilla.redhat.com/show_bug.cgi?id=1185604 (cherry picked from commit f5ce2b49585a14cefb6d02f61c8dcdf7628a8605) --- src/shared/selinux-util.c | 1 + 1 file changed, 1 insertion(+) diff --git a/src/shared/selinux-util.c b/src/shared/selinux-util.c index a2233e0cf..a46ddf849 100644 --- a/src/shared/selinux-util.c +++ b/src/shared/selinux-util.c @@ -117,6 +117,7 @@ void mac_selinux_finish(void) { return; selabel_close(label_hnd); + label_hnd = NULL; #endif }