Commit message: drivers/gpu/drm/radeon/radeon_atombios.c: range check issues

This change makes the array larger, "MAX_SUPPORTED_TV_TIMING_V1_2" is 3
and the original size "MAX_SUPPORTED_TV_TIMING" is 2.

Also there were checks that were off by one.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
CVE: CVE-2010-5331
CWE: CWE-119
Vulnerability description: In the Linux kernel before 2.6.34, a range check issue in drivers/gpu/drm/radeon/atombios.c could cause an off by one (buffer overflow) problem. NOTE: At least one Linux maintainer believes that this CVE is incorrectly assigned and should be rejected because the value is hard coded and are not user-controllable where it is used

Project: linux
File: radeon_atombios.c

bool radeon_atom_get_tv_timings(struct radeon_device *rdev, int index,
				struct drm_display_mode *mode)
{
	struct radeon_mode_info *mode_info = &rdev->mode_info;
	ATOM_ANALOG_TV_INFO *tv_info;
	ATOM_ANALOG_TV_INFO_V1_2 *tv_info_v1_2;
	ATOM_DTD_FORMAT *dtd_timings;
	int data_index = GetIndexIntoMasterTable(DATA, AnalogTV_Info);
	u8 frev, crev;
	u16 data_offset, misc;

	if (!atom_parse_data_header(mode_info->atom_context, data_index, NULL,
				    &frev, &crev, &data_offset))
		return false;

 	switch (crev) {
 	case 1:
 		tv_info = (ATOM_ANALOG_TV_INFO *)(mode_info->atom_context->bios + data_offset);
		if (index > MAX_SUPPORTED_TV_TIMING)
 			return false;
 
 		mode->crtc_htotal = le16_to_cpu(tv_info->aModeTimings[index].usCRTC_H_Total);
		mode->crtc_hdisplay = le16_to_cpu(tv_info->aModeTimings[index].usCRTC_H_Disp);
		mode->crtc_hsync_start = le16_to_cpu(tv_info->aModeTimings[index].usCRTC_H_SyncStart);
		mode->crtc_hsync_end = le16_to_cpu(tv_info->aModeTimings[index].usCRTC_H_SyncStart) +
			le16_to_cpu(tv_info->aModeTimings[index].usCRTC_H_SyncWidth);

		mode->crtc_vtotal = le16_to_cpu(tv_info->aModeTimings[index].usCRTC_V_Total);
		mode->crtc_vdisplay = le16_to_cpu(tv_info->aModeTimings[index].usCRTC_V_Disp);
		mode->crtc_vsync_start = le16_to_cpu(tv_info->aModeTimings[index].usCRTC_V_SyncStart);
		mode->crtc_vsync_end = le16_to_cpu(tv_info->aModeTimings[index].usCRTC_V_SyncStart) +
			le16_to_cpu(tv_info->aModeTimings[index].usCRTC_V_SyncWidth);

		mode->flags = 0;
		misc = le16_to_cpu(tv_info->aModeTimings[index].susModeMiscInfo.usAccess);
		if (misc & ATOM_VSYNC_POLARITY)
			mode->flags |= DRM_MODE_FLAG_NVSYNC;
		if (misc & ATOM_HSYNC_POLARITY)
			mode->flags |= DRM_MODE_FLAG_NHSYNC;
		if (misc & ATOM_COMPOSITESYNC)
			mode->flags |= DRM_MODE_FLAG_CSYNC;
		if (misc & ATOM_INTERLACE)
			mode->flags |= DRM_MODE_FLAG_INTERLACE;
		if (misc & ATOM_DOUBLE_CLOCK_MODE)
			mode->flags |= DRM_MODE_FLAG_DBLSCAN;

		mode->clock = le16_to_cpu(tv_info->aModeTimings[index].usPixelClock) * 10;

		if (index == 1) {
			/* PAL timings appear to have wrong values for totals */
			mode->crtc_htotal -= 1;
			mode->crtc_vtotal -= 1;
		}
 		break;
 	case 2:
 		tv_info_v1_2 = (ATOM_ANALOG_TV_INFO_V1_2 *)(mode_info->atom_context->bios + data_offset);
		if (index > MAX_SUPPORTED_TV_TIMING_V1_2)
 			return false;
 
 		dtd_timings = &tv_info_v1_2->aModeTimings[index];
		mode->crtc_htotal = le16_to_cpu(dtd_timings->usHActive) +
			le16_to_cpu(dtd_timings->usHBlanking_Time);
		mode->crtc_hdisplay = le16_to_cpu(dtd_timings->usHActive);
		mode->crtc_hsync_start = le16_to_cpu(dtd_timings->usHActive) +
			le16_to_cpu(dtd_timings->usHSyncOffset);
		mode->crtc_hsync_end = mode->crtc_hsync_start +
			le16_to_cpu(dtd_timings->usHSyncWidth);

		mode->crtc_vtotal = le16_to_cpu(dtd_timings->usVActive) +
			le16_to_cpu(dtd_timings->usVBlanking_Time);
		mode->crtc_vdisplay = le16_to_cpu(dtd_timings->usVActive);
		mode->crtc_vsync_start = le16_to_cpu(dtd_timings->usVActive) +
			le16_to_cpu(dtd_timings->usVSyncOffset);
		mode->crtc_vsync_end = mode->crtc_vsync_start +
			le16_to_cpu(dtd_timings->usVSyncWidth);

		mode->flags = 0;
		misc = le16_to_cpu(dtd_timings->susModeMiscInfo.usAccess);
		if (misc & ATOM_VSYNC_POLARITY)
			mode->flags |= DRM_MODE_FLAG_NVSYNC;
		if (misc & ATOM_HSYNC_POLARITY)
			mode->flags |= DRM_MODE_FLAG_NHSYNC;
		if (misc & ATOM_COMPOSITESYNC)
			mode->flags |= DRM_MODE_FLAG_CSYNC;
		if (misc & ATOM_INTERLACE)
			mode->flags |= DRM_MODE_FLAG_INTERLACE;
		if (misc & ATOM_DOUBLE_CLOCK_MODE)
			mode->flags |= DRM_MODE_FLAG_DBLSCAN;

		mode->clock = le16_to_cpu(dtd_timings->usPixClk) * 10;
		break;
	}
	return true;
}