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CVE-2014-1438 x86: exceptions are not cleared in AMD FXSAVE workaround (rhbz 1053599 1052914)

This commit is contained in:
Josh Boyer 2014-01-15 08:42:47 -05:00
parent 9c8545ae3e
commit f617e6188b
2 changed files with 57 additions and 0 deletions
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9
kernel.spec
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@ -763,6 +763,9 @@ Patch25182: Input-ALPS-add-support-for-Dolphin-devices.patch
#rhbz 1040128
Patch25183: ipv6-route-cache-expiration.patch
#CVE-2014-1438 rhbz 1053599 1052914
Patch25184: x86-fpu-amd-clear-exceptions-in-amd-fxsave-workaround.patch
# END OF PATCH DEFINITIONS
%endif
@ -1465,6 +1468,9 @@ ApplyPatch Input-ALPS-add-support-for-Dolphin-devices.patch
#rhbz 1040128
ApplyPatch ipv6-route-cache-expiration.patch
#CVE-2014-1438 rhbz 1053599 1052914
ApplyPatch x86-fpu-amd-clear-exceptions-in-amd-fxsave-workaround.patch
# END OF PATCH APPLICATIONS
%endif
@ -2277,6 +2283,9 @@ fi
# and build.
%changelog
* Wed Jan 15 2014 Josh Boyer <jwboyer@fedoraproject.org>
- CVE-2014-1438 x86: exceptions are not cleared in AMD FXSAVE workaround (rhbz 1053599 1052914)
* Tue Jan 14 2014 Josh Boyer <jwboyer@fedoraproject.org>
- Fix k-m-e Provides to be explicit to only the package flavor (rhbz 1046246)

48
x86-fpu-amd-clear-exceptions-in-amd-fxsave-workaround.patch Normal file
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@ -0,0 +1,48 @@
Bugzilla: 1053599
Upstream-status: 3.13 and 3.12.8
From 26bef1318adc1b3a530ecc807ef99346db2aa8b0 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Sat, 11 Jan 2014 19:15:52 -0800
Subject: x86, fpu, amd: Clear exceptions in AMD FXSAVE workaround
From: Linus Torvalds <torvalds@linux-foundation.org>
commit 26bef1318adc1b3a530ecc807ef99346db2aa8b0 upstream.
Before we do an EMMS in the AMD FXSAVE information leak workaround we
need to clear any pending exceptions, otherwise we trap with a
floating-point exception inside this code.
Reported-by: halfdog <me@halfdog.net>
Tested-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/CA%2B55aFxQnY_PCG_n4=0w-VG=YLXL-yr7oMxyy0WU2gCBAf3ydg@mail.gmail.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/fpu-internal.h | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
--- a/arch/x86/include/asm/fpu-internal.h
+++ b/arch/x86/include/asm/fpu-internal.h
@@ -293,12 +293,13 @@ static inline int restore_fpu_checking(s
/* AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception
is pending. Clear the x87 state here by setting it to fixed
values. "m" is a random variable that should be in L1 */
- alternative_input(
- ASM_NOP8 ASM_NOP2,
- "emms\n\t" /* clear stack tags */
- "fildl %P[addr]", /* set F?P to defined value */
- X86_FEATURE_FXSAVE_LEAK,
- [addr] "m" (tsk->thread.fpu.has_fpu));
+ if (unlikely(static_cpu_has(X86_FEATURE_FXSAVE_LEAK))) {
+ asm volatile(
+ "fnclex\n\t"
+ "emms\n\t"
+ "fildl %P[addr]" /* set F?P to defined value */
+ : : [addr] "m" (tsk->thread.fpu.has_fpu));
+ }
return fpu_restore_checking(&tsk->thread.fpu);
}