[FFmpeg-cvslog] avcodec/vmdvideo: Check len before using it in method 3

[Michael Niedermayer]

ffmpeg | branch: release/0.10 | Michael Niedermayer <michaelni at gmx.at> | Tue Dec 16 16:24:55 2014 +0100| [87ec3c615689e3d8bce36f1a168d908c7502b867] | committer: Michael Niedermayer

avcodec/vmdvideo: Check len before using it in method 3

Fixes out of array access
Fixes: asan_heap-oob_4d23ba_91_cov_3853393937_128.vmd

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
(cherry picked from commit 3030fb7e0d41836f8add6399e9a7c7b740b48bfd)

Conflicts:

	libavcodec/vmdav.c

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=87ec3c615689e3d8bce36f1a168d908c7502b867
---

 libavcodec/vmdav.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/libavcodec/vmdav.c b/libavcodec/vmdav.c
index 1e5f2ca..2b491ad 100644
--- a/libavcodec/vmdav.c
+++ b/libavcodec/vmdav.c
@@ -319,8 +319,12 @@ static void vmd_decode(VmdVideoContext *s)
                             len = rle_unpack(gb.buffer, &dp[ofs],
                                              len, bytestream2_get_bytes_left(&gb),
                                              frame_width - ofs);
-                        else
+                        else {
+                            if (ofs + len > frame_width ||
+                                bytestream2_get_bytes_left(&gb) < len)
+                                return;
                             bytestream2_get_buffer(&gb, &dp[ofs], len);
+                        }
                         bytestream2_skip(&gb, len);
                     } else {
                         /* interframe pixel copy */