X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fvmnc.c;h=7f441bc4bd3d6c70b5023ee2a84588cf24407322;hb=e83717e63eab1f1b78dc0990e5b8e927097fca29;hp=30b1414e494a5f7cba3bb8c8df31c2b7753319bd;hpb=9a88a47be4da9cd25a582feec7cc36790500b481;p=ffmpeg

diff --git a/libavcodec/vmnc.c b/libavcodec/vmnc.c
index 30b1414e494..7f441bc4bd3 100644
--- a/libavcodec/vmnc.c
+++ b/libavcodec/vmnc.c
@@ -333,10 +333,14 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
     uint8_t *outptr;
     int dx, dy, w, h, depth, enc, chunks, res, size_left, ret;
 
-    if ((ret = ff_reget_buffer(avctx, c->pic)) < 0)
-        return ret;
-
     bytestream2_init(gb, buf, buf_size);
+    bytestream2_skip(gb, 2);
+    chunks = bytestream2_get_be16(gb);
+    if (12LL * chunks > bytestream2_get_bytes_left(gb))
+        return AVERROR_INVALIDDATA;
+
+    if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0)
+        return ret;
 
     c->pic->key_frame = 0;
     c->pic->pict_type = AV_PICTURE_TYPE_P;
@@ -369,8 +373,7 @@ static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
             }
         }
     }
-    bytestream2_skip(gb, 2);
-    chunks = bytestream2_get_be16(gb);
+
     while (chunks--) {
         if (bytestream2_get_bytes_left(gb) < 12) {
             av_log(avctx, AV_LOG_ERROR, "Premature end of data!\n");