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authorMatthew Garrett <mjg59@google.com>2017-08-25 18:50:15 +0300
committerIngo Molnar <mingo@kernel.org>2017-08-26 10:20:33 +0300
commitccc829ba3624beb9a703fc995d016b836d9eead8 (patch)
treeb1791e31decb96c4fad4cd24b6b9dce5a351d2eb /drivers/firmware/efi/Kconfig
parent3cb9bc85029f2ceb7a5babadcab445c7cb861da8 (diff)
downloadlinux-ccc829ba3624beb9a703fc995d016b836d9eead8.tar.xz
efi/libstub: Enable reset attack mitigation
If a machine is reset while secrets are present in RAM, it may be possible for code executed after the reboot to extract those secrets from untouched memory. The Trusted Computing Group specified a mechanism for requesting that the firmware clear all RAM on reset before booting another OS. This is done by setting the MemoryOverwriteRequestControl variable at startup. If userspace can ensure that all secrets are removed as part of a controlled shutdown, it can reset this variable to 0 before triggering a hardware reboot. Signed-off-by: Matthew Garrett <mjg59@google.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-efi@vger.kernel.org Link: http://lkml.kernel.org/r/20170825155019.6740-2-ard.biesheuvel@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/firmware/efi/Kconfig')
-rw-r--r--drivers/firmware/efi/Kconfig10
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig
index 394db40ed374..2b4c39fdfa91 100644
--- a/drivers/firmware/efi/Kconfig
+++ b/drivers/firmware/efi/Kconfig
@@ -151,6 +151,16 @@ config APPLE_PROPERTIES
If unsure, say Y if you have a Mac. Otherwise N.
+config RESET_ATTACK_MITIGATION
+ bool "Reset memory attack mitigation"
+ depends on EFI_STUB
+ help
+ Request that the firmware clear the contents of RAM after a reboot
+ using the TCG Platform Reset Attack Mitigation specification. This
+ protects against an attacker forcibly rebooting the system while it
+ still contains secrets in RAM, booting another OS and extracting the
+ secrets.
+
endmenu
config UEFI_CPER