avformat/avidec: Check avio_read() return before using the results for meta-data

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavformat/avidec.c

@@ -308,7 +308,8 @@ static int avi_read_tag(AVFormatContext *s, AVStream *st, uint32_t tag,
     value = av_malloc(size + 1);
     if (!value)
         return AVERROR(ENOMEM);
-    avio_read(pb, value, size);
+    if (avio_read(pb, value, size) != size)
+        return AVERROR_INVALIDDATA;
     value[size] = 0;
 
     AV_WL32(key, tag);