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>
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 7f39253..eadaf48 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1576,19 +1576,28 @@
}
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 @@
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: