[FFmpeg-cvslog] dvdsubdec: validate offset2 similar to offset1

[Andreas Cadhalpun]

ffmpeg | branch: release/2.8 | Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com> | Tue Nov 10 22:14:39 2015 +0100| [df31acda644a83818f4be465c927329ddd9a9816] | committer: Andreas Cadhalpun

dvdsubdec: validate offset2 similar to offset1

If it is negative, it causes segmentation faults in decode_rle.

Reviewed-by: Michael Niedermayer <michael at niedermayer.cc>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
(cherry picked from commit f621749d1181987b3f815c6766ea66d6c5d55198)
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=df31acda644a83818f4be465c927329ddd9a9816
---

 libavcodec/dvdsubdec.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/dvdsubdec.c b/libavcodec/dvdsubdec.c
index 7120f10..f009824 100644
--- a/libavcodec/dvdsubdec.c
+++ b/libavcodec/dvdsubdec.c
@@ -346,7 +346,7 @@ static int decode_dvd_subtitles(DVDSubContext *ctx, AVSubtitle *sub_header,
             }
         }
     the_end:
-        if (offset1 >= 0) {
+        if (offset1 >= 0 && offset2 >= 0) {
             int w, h;
             uint8_t *bitmap;