Patch "module: Add retpoline tag to VERMAGIC" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    module: Add retpoline tag to VERMAGIC

to the 4.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     module-add-retpoline-tag-to-vermagic.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 6cfb521ac0d5b97470883ff9b7facae264b7ab12 Mon Sep 17 00:00:00 2001
From: Andi Kleen <ak@linux.intel.com>
Date: Tue, 16 Jan 2018 12:52:28 -0800
Subject: module: Add retpoline tag to VERMAGIC

From: Andi Kleen <ak@linux.intel.com>

commit 6cfb521ac0d5b97470883ff9b7facae264b7ab12 upstream.

Add a marker for retpoline to the module VERMAGIC. This catches the case
when a non RETPOLINE compiled module gets loaded into a retpoline kernel,
making it insecure.

It doesn't handle the case when retpoline has been runtime disabled.  Even
in this case the match of the retcompile status will be enforced.  This
implies that even with retpoline run time disabled all modules loaded need
to be recompiled.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Cc: rusty@rustcorp.com.au
Cc: arjan.van.de.ven@intel.com
Cc: jeyu@kernel.org
Cc: torvalds@linux-foundation.org
Link: https://lkml.kernel.org/r/20180116205228.4890-1-andi@firstfloor.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 include/linux/vermagic.h |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/include/linux/vermagic.h
+++ b/include/linux/vermagic.h
@@ -24,10 +24,16 @@
 #ifndef MODULE_ARCH_VERMAGIC
 #define MODULE_ARCH_VERMAGIC ""
 #endif
+#ifdef RETPOLINE
+#define MODULE_VERMAGIC_RETPOLINE "retpoline "
+#else
+#define MODULE_VERMAGIC_RETPOLINE ""
+#endif
 
 #define VERMAGIC_STRING 						\
 	UTS_RELEASE " "							\
 	MODULE_VERMAGIC_SMP MODULE_VERMAGIC_PREEMPT 			\
 	MODULE_VERMAGIC_MODULE_UNLOAD MODULE_VERMAGIC_MODVERSIONS	\
-	MODULE_ARCH_VERMAGIC
+	MODULE_ARCH_VERMAGIC						\
+	MODULE_VERMAGIC_RETPOLINE
 


Patches currently in stable-queue which might be from ak@linux.intel.com are

queue-4.9/module-add-retpoline-tag-to-vermagic.patch
queue-4.9/x86-retpoline-fill-rsb-on-context-switch-for-affected-cpus.patch
queue-4.9/x86-retpoline-add-lfence-to-the-retpoline-rsb-filling-rsb-macros.patch