On Fri, 02 Apr 2021 09:47:49 +0200,
Takashi Iwai wrote:
>
> intel_dsm_platform_mux_info() tries to parse the ACPI package data
> from _DSM for the debug information, but it assumes the fixed format
> without checking what values are stored in the elements actually.
> When an unexpected value is returned from BIOS, it may lead to GPF or
> NULL dereference, as reported recently.
>
> Add the checks of the contents in the returned values and skip the
> values for invalid cases.
>
> BugLink: http://bugzilla.opensuse.org/show_bug.cgi?id=1184074
> Cc:
> Signed-off-by: Takashi Iwai
Scratch this one. I sent an older version mistakenly.
Will resubmit the right one.
Takashi
> ---
> drivers/gpu/drm/i915/display/intel_acpi.c | 12
> 1 file changed, 12 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_acpi.c
> b/drivers/gpu/drm/i915/display/intel_acpi.c
> index e21fb14d5e07..492ebc0a8257 100644
> --- a/drivers/gpu/drm/i915/display/intel_acpi.c
> +++ b/drivers/gpu/drm/i915/display/intel_acpi.c
> @@ -84,6 +84,11 @@ static void intel_dsm_platform_mux_info(acpi_handle
> dhandle)
> return;
> }
>
> + if (!pkg->package.count) {
> + DRM_DEBUG_DRIVER("no connection in _DSM\n");
> + return;
> + }
> +
> connector_count = >package.elements[0];
> DRM_DEBUG_DRIVER("MUX info connectors: %lld\n",
> (unsigned long long)connector_count->integer.value);
> @@ -91,6 +96,13 @@ static void intel_dsm_platform_mux_info(acpi_handle
> dhandle)
> union acpi_object *obj = >package.elements[i];
> union acpi_object *connector_id = >package.elements[0];
> union acpi_object *info = >package.elements[1];
> +
> + if (obj->type != ACPI_TYPE_PACKAGE || obj->package.count < 2 ||
> + info->type != ACPI_TYPE_BUFFER || info->buffer.length < 4) {
> + DRM_DEBUG_DRIVER("Invalid object for MUX #%d\n", i);
> + continue;
> + }
> +
> DRM_DEBUG_DRIVER("Connector id: 0x%016llx\n",
> (unsigned long long)connector_id->integer.value);
> DRM_DEBUG_DRIVER(" port id: %s\n",
> --
> 2.26.2
>
