X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fwcmv.c;h=04c597e7674616bd70eb6fa00d68604d22f2f5bb;hb=0bf3a7361d17d596a5044882098f56817db0e103;hp=384ceecd32f13b353a197e8d6f2c6405a0c6c30e;hpb=203bbaccfaaeac9548862e83792d38509a8c8167;p=ffmpeg

diff --git a/libavcodec/wcmv.c b/libavcodec/wcmv.c
index 384ceecd32f..04c597e7674 100644
--- a/libavcodec/wcmv.c
+++ b/libavcodec/wcmv.c
@@ -45,7 +45,7 @@ static int decode_frame(AVCodecContext *avctx,
 {
     WCMVContext *s = avctx->priv_data;
     AVFrame *frame = data;
-    int skip, blocks, zret, ret, intra = 0, bpp = s->bpp;
+    int skip, blocks, zret, ret, intra = 0, flags = 0, bpp = s->bpp;
     GetByteContext gb;
     uint8_t *dst;
 
@@ -56,21 +56,13 @@ static int decode_frame(AVCodecContext *avctx,
     }
 
     bytestream2_init(&gb, avpkt->data, avpkt->size);
+    blocks = bytestream2_get_le16(&gb);
+    if (!blocks)
+        flags |= FF_REGET_BUFFER_FLAG_READONLY;
 
-    if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
+    if ((ret = ff_reget_buffer(avctx, s->prev_frame, flags)) < 0)
         return ret;
 
-    if (s->prev_frame->data[0]) {
-        ret = av_frame_copy(frame, s->prev_frame);
-        if (ret < 0)
-            return ret;
-    } else {
-        ptrdiff_t linesize[4] = { frame->linesize[0], 0, 0, 0 };
-        av_image_fill_black(frame->data, linesize, avctx->pix_fmt, 0,
-                            avctx->width, avctx->height);
-    }
-
-    blocks = bytestream2_get_le16(&gb);
     if (blocks > 5) {
         GetByteContext bgb;
         int x = 0, size;
@@ -113,6 +105,8 @@ static int decode_frame(AVCodecContext *avctx,
             bytestream2_skip(&bgb, 4);
             w = bytestream2_get_le16(&bgb);
             h = bytestream2_get_le16(&bgb);
+            if (x + bpp * (int64_t)w * h > INT_MAX)
+                return AVERROR_INVALIDDATA;
             x += bpp * w * h;
         }
 
@@ -140,6 +134,8 @@ static int decode_frame(AVCodecContext *avctx,
             bytestream2_skip(&gb, 4);
             w = bytestream2_get_le16(&gb);
             h = bytestream2_get_le16(&gb);
+            if (x + bpp * (int64_t)w * h > INT_MAX)
+                return AVERROR_INVALIDDATA;
             x += bpp * w * h;
         }
 
@@ -158,6 +154,15 @@ static int decode_frame(AVCodecContext *avctx,
         bytestream2_seek(&gb, 2, SEEK_SET);
     }
 
+    if (bytestream2_get_bytes_left(&gb) < 8LL * blocks)
+        return AVERROR_INVALIDDATA;
+
+    if (!avctx->frame_number) {
+        ptrdiff_t linesize[4] = { s->prev_frame->linesize[0], 0, 0, 0 };
+        av_image_fill_black(s->prev_frame->data, linesize, avctx->pix_fmt, 0,
+                            avctx->width, avctx->height);
+    }
+
     for (int block = 0; block < blocks; block++) {
         int x, y, w, h;
 
@@ -175,7 +180,7 @@ static int decode_frame(AVCodecContext *avctx,
         if (w > avctx->width || h > avctx->height)
             return AVERROR_INVALIDDATA;
 
-        dst = frame->data[0] + (avctx->height - y - 1) * frame->linesize[0] + x * bpp;
+        dst = s->prev_frame->data[0] + (avctx->height - y - 1) * s->prev_frame->linesize[0] + x * bpp;
         for (int i = 0; i < h; i++) {
             s->zstream.next_out  = dst;
             s->zstream.avail_out = w * bpp;
@@ -187,15 +192,14 @@ static int decode_frame(AVCodecContext *avctx,
                 return AVERROR_INVALIDDATA;
             }
 
-            dst -= frame->linesize[0];
+            dst -= s->prev_frame->linesize[0];
         }
     }
 
-    frame->key_frame = intra;
-    frame->pict_type = intra ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
+    s->prev_frame->key_frame = intra;
+    s->prev_frame->pict_type = intra ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
 
-    av_frame_unref(s->prev_frame);
-    if ((ret = av_frame_ref(s->prev_frame, frame)) < 0)
+    if ((ret = av_frame_ref(frame, s->prev_frame)) < 0)
         return ret;
 
     *got_frame = 1;
@@ -245,7 +249,7 @@ static av_cold int decode_close(AVCodecContext *avctx)
     return 0;
 }
 
-AVCodec ff_wcmv_decoder = {
+const AVCodec ff_wcmv_decoder = {
     .name             = "wcmv",
     .long_name        = NULL_IF_CONFIG_SMALL("WinCAM Motion Video"),
     .type             = AVMEDIA_TYPE_VIDEO,