From df05c4383da3fc259763db9b905dff548e74e2be Mon Sep 17 00:00:00 2001
From: Kostya Shishkov <kostya.shishkov@gmail.com>
Date: Sat, 4 Apr 2020 12:27:55 +0200
Subject: [PATCH] codec_support/h263: validate that B-frame has enough
 reference data

---
 nihav-codec-support/src/codecs/h263/decoder.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/nihav-codec-support/src/codecs/h263/decoder.rs b/nihav-codec-support/src/codecs/h263/decoder.rs
index 7a88882..02d6075 100644
--- a/nihav-codec-support/src/codecs/h263/decoder.rs
+++ b/nihav-codec-support/src/codecs/h263/decoder.rs
@@ -213,6 +213,10 @@ impl H263BaseDecoder {
         }
         let is_b = pinfo.mode == Type::B;
 
+        if is_b && (self.mv_data.len() < self.mb_w * self.mb_h) {
+            return Err(DecoderError::MissingReference);
+        }
+
         let tsdiff = if pinfo.is_pb() { pinfo.ts.wrapping_sub(self.last_ts) >> 1 }
                      else { self.last_ts.wrapping_sub(self.next_ts) >> 1 };
         let bsdiff = if pinfo.is_pb() { (pinfo.get_pbinfo().get_trb() as u16) << 7 }
-- 
2.30.2