[FFmpeg-cvslog] a64: check that extradata exists before reading from it

[Anton Khirnov]

ffmpeg | branch: master | Anton Khirnov <anton at khirnov.net> | Sat May  3 10:44:17 2014 +0200| [3ef6c5264b2590781b4ed556443ff49709dd45fb] | committer: Anton Khirnov

a64: check that extradata exists before reading from it

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=3ef6c5264b2590781b4ed556443ff49709dd45fb
---

 libavformat/a64.c |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/libavformat/a64.c b/libavformat/a64.c
index 640e786..da8e310 100644
--- a/libavformat/a64.c
+++ b/libavformat/a64.c
@@ -35,6 +35,12 @@ static int a64_write_header(AVFormatContext *s)
         0x00, //charset_lifetime (multi only)
         0x00  //fps in 50/fps;
     };
+
+    if (avctx->extradata_size < 4) {
+        av_log(s, AV_LOG_ERROR, "Missing extradata\n");
+        return AVERROR(EINVAL);
+    }
+
     switch (avctx->codec->id) {
     case AV_CODEC_ID_A64_MULTI:
         header[2] = 0x00;