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From: Andi Kleen <andi@firstfloor.org>
To: tglx@linutronix.de
Cc: torvalds@linux-foundation.org, dwmw@amazon.co.uk,
	linux-kernel@vger.kernel.org, gregkh@linux-foundation.org,
	arjan.van.de.ven@intel.com, jeyu@kernel.org,
	rusty@rustcorp.com.au, Andi Kleen <ak@linux.intel.com>
Subject: [PATCH v3] retpoline: Add retpoline tag to VERMAGIC
Date: Tue, 16 Jan 2018 12:52:28 -0800
Message-ID: <20180116205228.4890-1-andi@firstfloor.org> (raw)

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

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.

This supersedes an earlier patch that did the same checking using
a new module tag (so it's really a v3)

Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
 include/linux/vermagic.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/vermagic.h b/include/linux/vermagic.h
index bae807eb2933..853291714ae0 100644
--- a/include/linux/vermagic.h
+++ b/include/linux/vermagic.h
@@ -31,11 +31,17 @@
 #else
 #define MODULE_RANDSTRUCT_PLUGIN
 #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_RANDSTRUCT_PLUGIN
+	MODULE_RANDSTRUCT_PLUGIN					\
+	MODULE_VERMAGIC_RETPOLINE
 
-- 
2.14.3

             reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-16 20:52 Andi Kleen [this message]
2018-01-16 21:24 ` Thomas Gleixner
2018-01-16 22:34   ` Andi Kleen
2018-01-17  7:38     ` Thomas Gleixner
2018-01-17  5:11 ` Greg KH
2018-01-17 10:40 ` [tip:x86/pti] module: " tip-bot for Andi Kleen
2018-01-18 17:02   ` Josh Poimboeuf
2018-01-18 17:39     ` Thomas Gleixner

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