[FFmpeg-cvslog] tiffdec: Prevent illegal memory access caused by recycled pointers.

[Alex Converse]

ffmpeg | branch: master | Alex Converse <alex.converse at gmail.com> | Tue Mar  6 17:00:29 2012 -0800| [fd0be63049ed46660993d0550a4f0847a0b942ea] | committer: Alex Converse

tiffdec: Prevent illegal memory access caused by recycled pointers.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable at libav.org

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=fd0be63049ed46660993d0550a4f0847a0b942ea
---

 libavcodec/tiff.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
index 0ff6ceb..9ca9163 100644
--- a/libavcodec/tiff.c
+++ b/libavcodec/tiff.c
@@ -535,6 +535,8 @@ static int decode_frame(AVCodecContext *avctx,
         av_log(avctx, AV_LOG_ERROR, "The answer to life, universe and everything is not correct!\n");
         return -1;
     }
+    // Reset these pointers so we can tell if they were set this frame
+    s->stripsizes = s->stripdata = NULL;
     /* parse image file directory */
     off = tget_long(&buf, le);
     if (off >= UINT_MAX - 14 || end_buf - orig_buf < off + 14) {