2018-01-15 14:26:15 +03:00
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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2018-01-06 17:13:39 +03:00
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From: Andy Lutomirski <luto@kernel.org>
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Date: Mon, 4 Dec 2017 15:07:14 +0100
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2018-01-15 14:26:15 +03:00
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Subject: [PATCH] x86/entry/gdt: Put per-CPU GDT remaps in ascending order
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2018-01-06 17:13:39 +03:00
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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CVE-2017-5754
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We currently have CPU 0's GDT at the top of the GDT range and
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higher-numbered CPUs at lower addresses. This happens because the
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fixmap is upside down (index 0 is the top of the fixmap).
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Flip it so that GDTs are in ascending order by virtual address.
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This will simplify a future patch that will generalize the GDT
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remap to contain multiple pages.
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Signed-off-by: Andy Lutomirski <luto@kernel.org>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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Reviewed-by: Borislav Petkov <bp@suse.de>
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Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Cc: Borislav Petkov <bp@alien8.de>
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Cc: Borislav Petkov <bpetkov@suse.de>
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Cc: Brian Gerst <brgerst@gmail.com>
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Cc: Dave Hansen <dave.hansen@intel.com>
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Cc: Dave Hansen <dave.hansen@linux.intel.com>
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Cc: David Laight <David.Laight@aculab.com>
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Cc: Denys Vlasenko <dvlasenk@redhat.com>
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Cc: Eduardo Valentin <eduval@amazon.com>
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Cc: Greg KH <gregkh@linuxfoundation.org>
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Cc: H. Peter Anvin <hpa@zytor.com>
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Cc: Josh Poimboeuf <jpoimboe@redhat.com>
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Cc: Juergen Gross <jgross@suse.com>
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Cc: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Rik van Riel <riel@redhat.com>
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Cc: Will Deacon <will.deacon@arm.com>
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Cc: aliguori@amazon.com
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Cc: daniel.gruss@iaik.tugraz.at
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Cc: hughd@google.com
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Cc: keescook@google.com
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Link: https://lkml.kernel.org/r/20171204150605.471561421@linutronix.de
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit aaeed3aeb39c1ba69f0a49baec8cb728121d0a91)
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Signed-off-by: Andy Whitcroft <apw@canonical.com>
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Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>
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(cherry picked from commit 9c37967fad2d6a525df53e0a40edcd652e5abaae)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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arch/x86/include/asm/desc.h | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/arch/x86/include/asm/desc.h b/arch/x86/include/asm/desc.h
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index f995e5a09136..22ee0a93b4f7 100644
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--- a/arch/x86/include/asm/desc.h
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+++ b/arch/x86/include/asm/desc.h
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@@ -61,7 +61,7 @@ static inline struct desc_struct *get_current_gdt_rw(void)
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/* Get the fixmap index for a specific processor */
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static inline unsigned int get_cpu_gdt_ro_index(int cpu)
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{
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- return FIX_GDT_REMAP_BEGIN + cpu;
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+ return FIX_GDT_REMAP_END - cpu;
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}
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/* Provide the fixmap address of the remapped GDT */
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--
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2.14.2
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