From: Ville Syrjälä ville.syrjala@linux.intel.com
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. --- drivers/gpu/drm/drm_edid.c | 33 +++++++++++++++++++++------------ 1 files changed, 21 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index aa28d1c..2611ba8 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -1561,19 +1561,28 @@ 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, " @@ -1669,7 +1678,7 @@ 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: