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From: Takashi Iwai <tiwai@suse.de>
To: Jani Nikula <jani.nikula@linux.intel.com>,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2] drm/i915: Fix invalid access to ACPI _DSM objects
Date: Fri,  2 Apr 2021 10:23:17 +0200	[thread overview]
Message-ID: <20210402082317.871-1-tiwai@suse.de> (raw)

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@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 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];
+		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


WARNING: multiple messages have this Message-ID (diff)
From: Takashi Iwai <tiwai@suse.de>
To: Jani Nikula <jani.nikula@linux.intel.com>,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: [Intel-gfx] [PATCH v2] drm/i915: Fix invalid access to ACPI _DSM objects
Date: Fri,  2 Apr 2021 10:23:17 +0200	[thread overview]
Message-ID: <20210402082317.871-1-tiwai@suse.de> (raw)

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@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 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];
+		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@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/intel-gfx

             reply	other threads:[~2021-04-02  8:23 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-02  8:23 Takashi Iwai [this message]
2021-04-02  8:23 ` [Intel-gfx] [PATCH v2] drm/i915: Fix invalid access to ACPI _DSM objects Takashi Iwai
2021-04-02  8:39 ` [Intel-gfx] ✗ Fi.CI.DOCS: warning for drm/i915: Fix invalid access to ACPI _DSM objects (rev2) Patchwork
2021-04-02  9:05 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2021-04-02 10:27 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork
2021-04-07 16:34 ` [Intel-gfx] [PATCH v2] drm/i915: Fix invalid access to ACPI _DSM objects Ville Syrjälä
2021-04-07 16:34   ` Ville Syrjälä
2021-04-07 16:56   ` Takashi Iwai
2021-04-07 16:56     ` Takashi Iwai
2021-04-07 21:28     ` Ville Syrjälä
2021-04-07 21:28       ` Ville Syrjälä
2021-04-08  7:51       ` Takashi Iwai
2021-04-08  7:51         ` Takashi Iwai
2021-04-08 16:34         ` Takashi Iwai
2021-04-08 16:34           ` Takashi Iwai
2021-04-08 16:56           ` Ville Syrjälä
2021-04-08 16:56             ` Ville Syrjälä
2021-04-08 17:29             ` Takashi Iwai
2021-04-08 17:29               ` Takashi Iwai

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