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| author | Matthew Garrett <mjg59@google.com> | 2017-08-25 17:50:15 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-08-26 09:20:33 +0200 |
| commit | ccc829ba3624beb9a703fc995d016b836d9eead8 (patch) | |
| tree | b1791e31decb96c4fad4cd24b6b9dce5a351d2eb /drivers/firmware/efi/libstub/arm-stub.c | |
| parent | Merge branch 'x86/mm' into efi/core, to pick up dependencies (diff) | |
| download | linux-ccc829ba3624beb9a703fc995d016b836d9eead8.tar.xz linux-ccc829ba3624beb9a703fc995d016b836d9eead8.zip | |
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/libstub/arm-stub.c')
| -rw-r--r-- | drivers/firmware/efi/libstub/arm-stub.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/arm-stub.c b/drivers/firmware/efi/libstub/arm-stub.c index 8181ac179d14..1cb2d1c070c3 100644 --- a/drivers/firmware/efi/libstub/arm-stub.c +++ b/drivers/firmware/efi/libstub/arm-stub.c @@ -192,6 +192,9 @@ unsigned long efi_entry(void *handle, efi_system_table_t *sys_table, goto fail_free_cmdline; } + /* Ask the firmware to clear memory on unclean shutdown */ + efi_enable_reset_attack_mitigation(sys_table); + secure_boot = efi_get_secureboot(sys_table); /* |