X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fwmv2dec.c;h=92daa1639e5e9b7a2572b891d5d1c964f4213af2;hb=f4ea930a119298c6110ee4e3d24219a66e27e230;hp=4f97d9227ce1e032d9951e8eb23180ad6b95fedb;hpb=14fe81b3a88dfe4dbac12e8715f9a3f05b5ef1bf;p=ffmpeg

diff --git a/libavcodec/wmv2dec.c b/libavcodec/wmv2dec.c
index 4f97d9227ce..92daa1639e5 100644
--- a/libavcodec/wmv2dec.c
+++ b/libavcodec/wmv2dec.c
@@ -181,6 +181,14 @@ int ff_wmv2_decode_secondary_picture_header(MpegEncContext *s)
             }
 
             s->dc_table_index = get_bits1(&s->gb);
+
+            // at minimum one bit per macroblock is required at least in a valid frame,
+            // we discard frames much smaller than this. Frames smaller than 1/8 of the
+            // smallest "black/skip" frame generally contain not much recoverable content
+            // while at the same time they have the highest computational requirements
+            // per byte
+            if (get_bits_left(&s->gb) * 8LL < (s->width+15)/16 * ((s->height+15)/16))
+                return AVERROR_INVALIDDATA;
         }
         s->inter_intra_pred = 0;
         s->no_rounding      = 1;