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| author | Kees Cook <keescook@chromium.org> | 2013-04-10 12:24:22 -0700 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2013-04-11 13:53:19 -0700 |
| commit | 4eefbe792baedb474e256d35370849992fcf1c79 (patch) | |
| tree | 03a95dab4a014a7f36133f9660ca180b01df62d4 /arch/x86/include/asm/fixmap.h | |
| parent | 31880c37c11e28cb81c70757e38392b42e695dc6 (diff) | |
| download | linux-0-day-4eefbe792baedb474e256d35370849992fcf1c79.tar.gz linux-0-day-4eefbe792baedb474e256d35370849992fcf1c79.tar.xz | |
x86: Use a read-only IDT alias on all CPUs
Make a copy of the IDT (as seen via the "sidt" instruction) read-only.
This primarily removes the IDT from being a target for arbitrary memory
write attacks, and has the added benefit of also not leaking the kernel
base offset, if it has been relocated.
We already did this on vendor == Intel and family == 5 because of the
F0 0F bug -- regardless of if a particular CPU had the F0 0F bug or
not. Since the workaround was so cheap, there simply was no reason to
be very specific. This patch extends the readonly alias to all CPUs,
but does not activate the #PF to #UD conversion code needed to deliver
the proper exception in the F0 0F case except on Intel family 5
processors.
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: http://lkml.kernel.org/r/20130410192422.GA17344@www.outflux.net
Cc: Eric Northup <digitaleric@google.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/include/asm/fixmap.h')
| -rw-r--r-- | arch/x86/include/asm/fixmap.h | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/arch/x86/include/asm/fixmap.h b/arch/x86/include/asm/fixmap.h index a09c28571064d..51b9e322cb8f1 100644 --- a/arch/x86/include/asm/fixmap.h +++ b/arch/x86/include/asm/fixmap.h @@ -104,9 +104,7 @@ enum fixed_addresses { FIX_LI_PCIA, /* Lithium PCI Bridge A */ FIX_LI_PCIB, /* Lithium PCI Bridge B */ #endif -#ifdef CONFIG_X86_F00F_BUG - FIX_F00F_IDT, /* Virtual mapping for IDT */ -#endif + FIX_RO_IDT, /* Virtual mapping for read-only IDT */ #ifdef CONFIG_X86_CYCLONE_TIMER FIX_CYCLONE_TIMER, /*cyclone timer register*/ #endif |