[FFmpeg-cvslog] xan: check size_segment before reading, fixes out of array read.

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Mon Nov 12 20:42:33 2012 +0100| [0e239b22dbbe6808ac08ca72825f734076d4dc81] | committer: Michael Niedermayer

xan: check size_segment before reading, fixes out of array read.

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=0e239b22dbbe6808ac08ca72825f734076d4dc81
---

 libavcodec/xan.c |   12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/libavcodec/xan.c b/libavcodec/xan.c
index 25e62e6..bccbe24 100644
--- a/libavcodec/xan.c
+++ b/libavcodec/xan.c
@@ -359,17 +359,29 @@ static int xan_wc3_decode_frame(XanContext *s) {
 
         case 9:
         case 19:
+            if (buf_end - size_segment < 1) {
+                av_log(s->avctx, AV_LOG_ERROR, "size_segment overread\n");
+                return AVERROR_INVALIDDATA;
+            }
             size = *size_segment++;
             break;
 
         case 10:
         case 20:
+            if (buf_end - size_segment < 2) {
+                av_log(s->avctx, AV_LOG_ERROR, "size_segment overread\n");
+                return AVERROR_INVALIDDATA;
+            }
             size = AV_RB16(&size_segment[0]);
             size_segment += 2;
             break;
 
         case 11:
         case 21:
+            if (buf_end - size_segment < 3) {
+                av_log(s->avctx, AV_LOG_ERROR, "size_segment overread\n");
+                return AVERROR_INVALIDDATA;
+            }
             size = AV_RB24(size_segment);
             size_segment += 3;
             break;