x86/CPU/AMD: Do not leak quotient data after a division by 0

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commit 77245f1c3c upstream.

Under certain circumstances, an integer division by 0 which faults, can
leave stale quotient data from a previous division operation on Zen1
microarchitectures.

Do a dummy division 0/1 before returning from the #DE exception handler
in order to avoid any leaks of potentially sensitive data.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Borislav Petkov (AMD) 2023-08-05 00:06:43 +02:00 • committed by Greg Kroah-Hartman

parent 493c80a4f2

commit c9c0b889e2

4 changed files with 24 additions and 0 deletions

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1

arch/x86/include/asm/cpufeatures.h

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2

arch/x86/include/asm/processor.h

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19

arch/x86/kernel/cpu/amd.c

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2

arch/x86/kernel/traps.c

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