drm/radeon: implement bounds checking on thermal controller lookup

Don't read past the end of the array if we encounter an unknown
thermal controller.

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
index e368b3027cba4b6a43283b10b45482bcf9bffe2e..01b90b4f5e226d9145fc028f8cbd9c7b78767946 100644 (file)
--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -2009,7 +2009,8 @@ static int radeon_atombios_parse_power_table_1_3(struct radeon_device *rdev)
        power_info = (union power_info *)(mode_info->atom_context->bios + data_offset);
 
        /* add the i2c bus for thermal/fan chip */
-       if (power_info->info.ucOverdriveThermalController > 0) {
+       if ((power_info->info.ucOverdriveThermalController > 0) &&
+           (power_info->info.ucOverdriveThermalController < ARRAY_SIZE(thermal_controller_names))) {
                DRM_INFO("Possible %s thermal controller at 0x%02x\n",
                         thermal_controller_names[power_info->info.ucOverdriveThermalController],
                         power_info->info.ucOverdriveControllerAddress >> 1);
@@ -2213,7 +2214,7 @@ static void radeon_atombios_add_pplib_thermal_controller(struct radeon_device *r
                           (controller->ucType ==
                            ATOM_PP_THERMALCONTROLLER_EMC2103_WITH_INTERNAL)) {
                        DRM_INFO("Special thermal controller config\n");
-               } else {
+               } else if (controller->ucType < ARRAY_SIZE(pp_lib_thermal_controller_names)) {
                        DRM_INFO("Possible %s thermal controller at 0x%02x %s fan control\n",
                                 pp_lib_thermal_controller_names[controller->ucType],
                                 controller->ucI2cAddress >> 1,
@@ -2228,6 +2229,12 @@ static void radeon_atombios_add_pplib_thermal_controller(struct radeon_device *r
                                strlcpy(info.type, name, sizeof(info.type));
                                i2c_new_device(&rdev->pm.i2c_bus->adapter, &info);
                        }
+               } else {
+                       DRM_INFO("Unknown thermal controller type %d at 0x%02x %s fan control\n",
+                                controller->ucType,
+                                controller->ucI2cAddress >> 1,
+                                (controller->ucFanParameters &
+                                 ATOM_PP_FANPARAMETERS_NOFAN) ? "without" : "with");
                }
        }
 }