Hi experts,
On Thu, Nov 09, 2017 at 05:32:53PM +0000, David Howells wrote:
> From: Linn Crosetto <linn@xxxxxxx>
>
> 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 <linn@xxxxxxx>
> Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
> Reviewed-by: "Lee, Chun-Yi" <jlee@xxxxxxxx>
> cc: linux-acpi@xxxxxxxxxxxxxxx
I was looking at the lockdown pathes in v5.4-rc kernel and found that the
"acpi: Disable APEI error injection if the kernel is locked down" did not
merged with lockdown patch set. This patch be sent with Matthew's pull
request lockdown patches for 5.2:
http://kernsec.org/pipermail/linux-security-module-archive/2019-March/012033.html
But it didn't show in Morris's git:
https://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git/log/?h=next-lockdown
Maybe I missed some detail of this patch. Could anyone point out the
concern of this patch please?
> ---
>
> 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 b38737c83a24..6d71e1e97b20 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)))
>
> --
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Thanks
Joey Lee
