On Fri, Apr 02, 2021 at 10:23:17AM +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. > > v1->v2: Check the info contents before dereferencing, too > > BugLink: http://bugzilla.opensuse.org/show_bug.cgi?id=1184074 > Cc: <stable@xxxxxxxxxxxxxxx> > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> > --- > drivers/gpu/drm/i915/display/intel_acpi.c | 22 ++++++++++++++++++++-- > 1 file changed, 20 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_acpi.c b/drivers/gpu/drm/i915/display/intel_acpi.c > index e21fb14d5e07..833d0c1be4f1 100644 > --- a/drivers/gpu/drm/i915/display/intel_acpi.c > +++ b/drivers/gpu/drm/i915/display/intel_acpi.c > @@ -84,13 +84,31 @@ 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 = &pkg->package.elements[0]; > DRM_DEBUG_DRIVER("MUX info connectors: %lld\n", > (unsigned long long)connector_count->integer.value); > for (i = 1; i < pkg->package.count; i++) { > union acpi_object *obj = &pkg->package.elements[i]; > - union acpi_object *connector_id = &obj->package.elements[0]; > - union acpi_object *info = &obj->package.elements[1]; > + union acpi_object *connector_id; > + union acpi_object *info; > + > + if (obj->type != ACPI_TYPE_PACKAGE || obj->package.count < 2) { > + DRM_DEBUG_DRIVER("Invalid object for MUX #%d\n", i); > + continue; > + } > + > + connector_id = &obj->package.elements[0]; You don't want to check connector_id->type as well? > + info = &obj->package.elements[1]; > + if (info->type != ACPI_TYPE_BUFFER || info->buffer.length < 4) { > + DRM_DEBUG_DRIVER("Invalid info for MUX obj #%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 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Ville Syrjälä Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
