From 9fd67b4ed0714ab718f1f9bd14c344af336a6df7 Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <luto@MIT.EDU>
Date: Sun, 5 Jun 2011 13:50:19 -0400
Subject: x86-64: Give vvars their own page

Move vvars out of the vsyscall page into their own page and mark
it NX.

Without this patch, an attacker who can force a daemon to call
some fixed address could wait until the time contains, say,
0xCD80, and then execute the current time.

Signed-off-by: Andy Lutomirski <luto@mit.edu>
Cc: Jesper Juhl <jj@chaosbits.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: richard -rw- weinberger <richard.weinberger@gmail.com>
Cc: Mikael Pettersson <mikpe@it.uu.se>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Louis Rilling <Louis.Rilling@kerlabs.com>
Cc: Valdis.Kletnieks@vt.edu
Cc: pageexec@freemail.hu
Link: http://lkml.kernel.org/r/b1460f81dc4463d66ea3f2b5ce240f58d48effec.1307292171.git.luto@mit.edu
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/include/asm/fixmap.h | 1 +
 1 file changed, 1 insertion(+)

(limited to 'arch/x86/include/asm/fixmap.h')

diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h
index 4729b2b63117..460c74e4852c 100644
--- a/arch/x86/include/asm/fixmap.h
+++ b/arch/x86/include/asm/fixmap.h
@@ -78,6 +78,7 @@ enum fixed_addresses {
 	VSYSCALL_LAST_PAGE,
 	VSYSCALL_FIRST_PAGE = VSYSCALL_LAST_PAGE
 			    + ((VSYSCALL_END-VSYSCALL_START) >> PAGE_SHIFT) - 1,
+	VVAR_PAGE,
 	VSYSCALL_HPET,
 #endif
 	FIX_DBGP_BASE,
-- 
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