drm: edid: Add bounds checking to HDMI VSDB parsing

The length of HDMI VSDB must be at least 5 bytes. Other than the minimum,
nothing else about the length is specified. Check the length before
accessing any additional field beyond the minimum length.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Ville Syrjälä 2012-08-16 14:55:05 +00:00 committed by Dave Airlie
parent 9e50b9d55e
commit 8504072a2a

View file

@ -1576,19 +1576,28 @@ add_cea_modes(struct drm_connector *connector, struct edid *edid)
}
static void
parse_hdmi_vsdb(struct drm_connector *connector, uint8_t *db)
parse_hdmi_vsdb(struct drm_connector *connector, const u8 *db)
{
connector->eld[5] |= (db[6] >> 7) << 1; /* Supports_AI */
u8 len = cea_db_payload_len(db);
connector->dvi_dual = db[6] & 1;
connector->max_tmds_clock = db[7] * 5;
connector->latency_present[0] = db[8] >> 7;
connector->latency_present[1] = (db[8] >> 6) & 1;
connector->video_latency[0] = db[9];
connector->audio_latency[0] = db[10];
connector->video_latency[1] = db[11];
connector->audio_latency[1] = db[12];
if (len >= 6) {
connector->eld[5] |= (db[6] >> 7) << 1; /* Supports_AI */
connector->dvi_dual = db[6] & 1;
}
if (len >= 7)
connector->max_tmds_clock = db[7] * 5;
if (len >= 8) {
connector->latency_present[0] = db[8] >> 7;
connector->latency_present[1] = (db[8] >> 6) & 1;
}
if (len >= 9)
connector->video_latency[0] = db[9];
if (len >= 10)
connector->audio_latency[0] = db[10];
if (len >= 11)
connector->video_latency[1] = db[11];
if (len >= 12)
connector->audio_latency[1] = db[12];
DRM_LOG_KMS("HDMI: DVI dual %d, "
"max TMDS clock %d, "
@ -1684,7 +1693,7 @@ void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid)
break;
case VENDOR_BLOCK:
/* HDMI Vendor-Specific Data Block */
if (db[1] == 0x03 && db[2] == 0x0c && db[3] == 0)
if (dbl >= 5 && db[1] == 0x03 && db[2] == 0x0c && db[3] == 0)
parse_hdmi_vsdb(connector, db);
break;
default: