2014-08-25 14:33:49 +00:00
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From 53c38555d8cefb48bc19d3f9e7f2ffb5e5bacac2 Mon Sep 17 00:00:00 2001
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2014-08-20 17:22:24 +00:00
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From: Matthew Garrett <matthew.garrett@nebula.com>
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Date: Fri, 9 Aug 2013 03:33:56 -0400
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Subject: [PATCH] kexec: Disable at runtime if the kernel enforces module
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loading restrictions
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kexec permits the loading and execution of arbitrary code in ring 0, which
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is something that module signing enforcement is meant to prevent. It makes
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sense to disable kexec in this situation.
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Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
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---
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kernel/kexec.c | 8 ++++++++
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1 file changed, 8 insertions(+)
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diff --git a/kernel/kexec.c b/kernel/kexec.c
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index 0b49a0a58102..8e649f7c22e1 100644
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--- a/kernel/kexec.c
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+++ b/kernel/kexec.c
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@@ -36,6 +36,7 @@
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#include <linux/syscore_ops.h>
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#include <linux/compiler.h>
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#include <linux/hugetlb.h>
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+#include <linux/module.h>
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#include <asm/page.h>
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#include <asm/uaccess.h>
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@@ -1245,6 +1246,13 @@ SYSCALL_DEFINE4(kexec_load, unsigned long, entry, unsigned long, nr_segments,
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return -EPERM;
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/*
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+ * kexec can be used to circumvent module loading restrictions, so
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+ * prevent loading in that case
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+ */
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+ if (secure_modules())
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+ return -EPERM;
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+
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+ /*
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* Verify we have a legal set of flags
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* This leaves us room for future extensions.
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*/
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--
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1.9.3
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