From c2b3cf2c70d6ae4668f96386f6c444c4c391fde9 Mon Sep 17 00:00:00 2001 From: Takashi Iwai Date: Fri, 2 Apr 2021 10:23:17 +0200 Subject: [PATCH] drm/i915: Fix invalid access to ACPI _DSM objects MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit b6a37a93c9ac3900987c79b726d0bb3699d8db4e upstream. 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: Signed-off-by: Takashi Iwai Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20210402082317.871-1-tiwai@suse.de (cherry picked from commit 337d7a1621c7f02af867229990ac67c97da1b53a) Signed-off-by: Rodrigo Vivi Signed-off-by: Greg Kroah-Hartman --- 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 3456d33feb46..ce8182bd0b55 100644 --- a/drivers/gpu/drm/i915/display/intel_acpi.c +++ b/drivers/gpu/drm/i915/display/intel_acpi.c @@ -83,13 +83,31 @@ 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]; + 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",