From 4819829a3a42cb50f10a3ecb776ef0deb53adb50 Mon Sep 17 00:00:00 2001 From: Linn Crosetto Date: Wed, 8 Nov 2017 15:11:35 +0000 Subject: [PATCH] acpi: Disable APEI error injection if the kernel is locked down ACPI provides an error injection mechanism, EINJ, for debugging and testing the ACPI Platform Error Interface (APEI) and other RAS features. If supported by the firmware, ACPI specification 5.0 and later provide for a way to specify a physical memory address to which to inject the error. Injecting errors through EINJ can produce errors which to the platform are indistinguishable from real hardware errors. This can have undesirable side-effects, such as causing the platform to mark hardware as needing replacement. While it does not provide a method to load unauthenticated privileged code, the effect of these errors may persist across reboots and affect trust in the underlying hardware, so disable error injection through EINJ if the kernel is locked down. Signed-off-by: Linn Crosetto Signed-off-by: David Howells Reviewed-by: "Lee, Chun-Yi" cc: linux-acpi@vger.kernel.org Gbp-Pq: Topic features/all/lockdown Gbp-Pq: Name 0018-acpi-Disable-APEI-error-injection-if-the-kernel-is-l.patch --- drivers/acpi/apei/einj.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/acpi/apei/einj.c b/drivers/acpi/apei/einj.c index b38737c83a2..6d71e1e97b2 100644 --- a/drivers/acpi/apei/einj.c +++ b/drivers/acpi/apei/einj.c @@ -518,6 +518,9 @@ static int einj_error_inject(u32 type, u32 flags, u64 param1, u64 param2, int rc; u64 base_addr, size; + if (kernel_is_locked_down("ACPI error injection")) + return -EPERM; + /* If user manually set "flags", make sure it is legal */ if (flags && (flags & ~(SETWA_FLAGS_APICID|SETWA_FLAGS_MEM|SETWA_FLAGS_PCIE_SBDF))) -- 2.30.2