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From 3a82f8be03b07b84fa470c6e42cd87865aeaf701 Mon Sep 17 00:00:00 2001
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From: Will Woods <wwoods@redhat.com>
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Date: Fri, 13 Mar 2015 17:24:46 -0400
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Subject: [PATCH] selinux: fix SEGV during switch-root if SELinux policy loaded
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If you've got SELinux policy loaded, label_hnd is your labeling handle.
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When systemd is shutting down, we free that handle via mac_selinux_finish().
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But: switch_root() calls mkdir_p_label(), which tries to look up a label
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using that freed handle, and so we get a bunch of garbage and eventually
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SEGV in libselinux.
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(This doesn't happen in the switch-root from initramfs to real root because
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there's no SELinux policy loaded in initramfs, so label_hnd is NULL and we
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never attempt any lookups.)
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So: make sure that mac_selinux_finish() actually sets label_hnd to NULL, so
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nobody tries to use it after it becomes invalid.
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https://bugzilla.redhat.com/show_bug.cgi?id=1185604
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(cherry picked from commit f5ce2b49585a14cefb6d02f61c8dcdf7628a8605)
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---
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src/shared/selinux-util.c | 1 +
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1 file changed, 1 insertion(+)
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diff --git a/src/shared/selinux-util.c b/src/shared/selinux-util.c
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index a2233e0cfb..a46ddf8498 100644
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--- a/src/shared/selinux-util.c
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+++ b/src/shared/selinux-util.c
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@@ -117,6 +117,7 @@ void mac_selinux_finish(void) {
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return;
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selabel_close(label_hnd);
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+ label_hnd = NULL;
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#endif
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}
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