[FFmpeg-cvslog] flashsv: check for keyframe before using differential coding

[Janne Grunau]

ffmpeg | branch: master | Janne Grunau <janne-libav at jannau.net> | Sat Nov 24 15:50:03 2012 +0100| [5ae72f54532960cb9eae82a1c9e8d505106c022b] | committer: Janne Grunau

flashsv: check for keyframe before using differential coding

Fixes a segfault in te fuzzed sample resolutionchange.flv_s211713.

CC: libav-stable at libav.org

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=5ae72f54532960cb9eae82a1c9e8d505106c022b
---

 libavcodec/flashsv.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavcodec/flashsv.c b/libavcodec/flashsv.c
index 2ba3264..ac57f9f 100644
--- a/libavcodec/flashsv.c
+++ b/libavcodec/flashsv.c
@@ -377,6 +377,11 @@ static int flashsv_decode_frame(AVCodecContext *avctx, void *data,
                 }
 
                 if (has_diff) {
+                    if (!s->keyframe) {
+                        av_log(avctx, AV_LOG_ERROR,
+                               "inter frame without keyframe\n");
+                        return AVERROR_INVALIDDATA;
+                    }
                     s->diff_start  = get_bits(&gb, 8);
                     s->diff_height = get_bits(&gb, 8);
                     av_log(avctx, AV_LOG_DEBUG,