lavc: add error checking to apply_param_change.

libavcodec/utils.c

@@ -1321,46 +1321,59 @@ int avcodec_encode_subtitle(AVCodecContext *avctx, uint8_t *buf, int buf_size,
     return ret;
 }
 
-static void apply_param_change(AVCodecContext *avctx, AVPacket *avpkt)
+static int apply_param_change(AVCodecContext *avctx, AVPacket *avpkt)
 {
     int size = 0;
     const uint8_t *data;
     uint32_t flags;
 
-    if (!(avctx->codec->capabilities & CODEC_CAP_PARAM_CHANGE))
-        return;
-
     data = av_packet_get_side_data(avpkt, AV_PKT_DATA_PARAM_CHANGE, &size);
-    if (!data || size < 4)
-        return;
+    if (!data)
+        return 0;
+
+    if (!(avctx->codec->capabilities & CODEC_CAP_PARAM_CHANGE)) {
+        av_log(avctx, AV_LOG_ERROR, "This decoder does not support parameter "
+               "changes, but PARAM_CHANGE side data was sent to it.\n");
+        return AVERROR(EINVAL);
+    }
+
+    if (size < 4)
+        goto fail;
+
     flags = bytestream_get_le32(&data);
     size -= 4;
-    if (size < 4) /* Required for any of the changes */
-        return;
+
     if (flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_COUNT) {
+        if (size < 4)
+            goto fail;
         avctx->channels = bytestream_get_le32(&data);
         size -= 4;
     }
     if (flags & AV_SIDE_DATA_PARAM_CHANGE_CHANNEL_LAYOUT) {
         if (size < 8)
-            return;
+            goto fail;
         avctx->channel_layout = bytestream_get_le64(&data);
         size -= 8;
     }
-    if (size < 4)
-        return;
     if (flags & AV_SIDE_DATA_PARAM_CHANGE_SAMPLE_RATE) {
+        if (size < 4)
+            goto fail;
         avctx->sample_rate = bytestream_get_le32(&data);
         size -= 4;
     }
     if (flags & AV_SIDE_DATA_PARAM_CHANGE_DIMENSIONS) {
         if (size < 8)
-            return;
+            goto fail;
         avctx->width  = bytestream_get_le32(&data);
         avctx->height = bytestream_get_le32(&data);
         avcodec_set_dimensions(avctx, avctx->width, avctx->height);
         size -= 8;
     }
+
+    return 0;
+fail:
+    av_log(avctx, AV_LOG_ERROR, "PARAM_CHANGE side data too small.\n");
+    return AVERROR_INVALIDDATA;
 }
 
 int attribute_align_arg avcodec_decode_video2(AVCodecContext *avctx, AVFrame *picture,
@@ -1375,7 +1388,12 @@ int attribute_align_arg avcodec_decode_video2(AVCodecContext *avctx, AVFrame *pi
         return -1;
 
     avctx->pkt = avpkt;
-    apply_param_change(avctx, avpkt);
+    ret = apply_param_change(avctx, avpkt);
+    if (ret < 0) {
+        av_log(avctx, AV_LOG_ERROR, "Error applying parameter changes.\n");
+        if (avctx->err_recognition & AV_EF_EXPLODE)
+            return ret;
+    }
 
     avcodec_get_frame_defaults(picture);
 
@@ -1441,7 +1459,12 @@ int attribute_align_arg avcodec_decode_audio4(AVCodecContext *avctx,
         return AVERROR(EINVAL);
     }
 
-    apply_param_change(avctx, avpkt);
+    ret = apply_param_change(avctx, avpkt);
+    if (ret < 0) {
+        av_log(avctx, AV_LOG_ERROR, "Error applying parameter changes.\n");
+        if (avctx->err_recognition & AV_EF_EXPLODE)
+            return ret;
+    }
 
     avcodec_get_frame_defaults(frame);