2018-01-06 14:13:39 +00:00
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From d8fdea47d7fc1177aa0843a49dc89422ac6f4fea Mon Sep 17 00:00:00 2001
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From: Andy Lutomirski <luto@kernel.org>
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Date: Thu, 2 Nov 2017 00:59:02 -0700
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2018-01-08 10:50:09 +00:00
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Subject: [PATCH 090/242] x86/entry/64: Shrink paranoid_exit_restore and make
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2018-01-06 14:13:39 +00:00
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labels local
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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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paranoid_exit_restore was a copy of restore_regs_and_return_to_kernel.
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Merge them and make the paranoid_exit internal labels local.
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Keeping .Lparanoid_exit makes the code a bit shorter because it
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allows a 2-byte jnz instead of a 5-byte jnz.
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Saves 96 bytes of text.
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( This is still a bit suboptimal in a non-CONFIG_TRACE_IRQFLAGS
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kernel, but fixing that would make the code rather messy. )
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Signed-off-by: Andy Lutomirski <luto@kernel.org>
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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: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Thomas Gleixner <tglx@linutronix.de>
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Link: http://lkml.kernel.org/r/510d66a1895cda9473c84b1086f0bb974f22de6a.1509609304.git.luto@kernel.org
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Signed-off-by: Ingo Molnar <mingo@kernel.org>
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(cherry picked from commit e53178328c9b96fbdbc719e78c93b5687ee007c3)
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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 fb53fe10add935c3d0eb63199e43426eaf3b4299)
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Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
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---
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arch/x86/entry/entry_64.S | 13 +++++--------
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1 file changed, 5 insertions(+), 8 deletions(-)
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diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
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index a1a86e782a0e..6995f7e08aa1 100644
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--- a/arch/x86/entry/entry_64.S
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+++ b/arch/x86/entry/entry_64.S
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@@ -1136,17 +1136,14 @@ ENTRY(paranoid_exit)
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DISABLE_INTERRUPTS(CLBR_ANY)
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TRACE_IRQS_OFF_DEBUG
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testl %ebx, %ebx /* swapgs needed? */
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- jnz paranoid_exit_no_swapgs
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+ jnz .Lparanoid_exit_no_swapgs
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TRACE_IRQS_IRETQ
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SWAPGS_UNSAFE_STACK
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- jmp paranoid_exit_restore
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-paranoid_exit_no_swapgs:
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+ jmp .Lparanoid_exit_restore
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+.Lparanoid_exit_no_swapgs:
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TRACE_IRQS_IRETQ_DEBUG
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-paranoid_exit_restore:
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- RESTORE_EXTRA_REGS
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- RESTORE_C_REGS
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- REMOVE_PT_GPREGS_FROM_STACK 8
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- INTERRUPT_RETURN
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+.Lparanoid_exit_restore:
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+ jmp restore_regs_and_return_to_kernel
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END(paranoid_exit)
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/*
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--
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2.14.2
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