[FFmpeg-cvslog] avcodec/rasc: Fix off by 1 error in vertical coordinate

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Tue Oct  2 03:04:51 2018 +0200| [9a9034958aec8c30ee898db23cb691863801ea1f] | committer: Michael Niedermayer

avcodec/rasc: Fix off by 1 error in vertical coordinate

Fixes: out of array read
Fixes: 10311/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_RASC_fuzzer-4856330905452544

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=9a9034958aec8c30ee898db23cb691863801ea1f
---

 libavcodec/rasc.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libavcodec/rasc.c b/libavcodec/rasc.c
index fbbb134f4b..eb021681c6 100644
--- a/libavcodec/rasc.c
+++ b/libavcodec/rasc.c
@@ -272,9 +272,9 @@ static int decode_move(AVCodecContext *avctx,
         if (!s->frame2->data[0] || !s->frame1->data[0])
             return AVERROR_INVALIDDATA;
 
-        b1 = s->frame1->data[0] + s->frame1->linesize[0] * (start_y + h) + start_x * s->bpp;
-        b2 = s->frame2->data[0] + s->frame2->linesize[0] * (start_y + h) + start_x * s->bpp;
-        e2 = s->frame2->data[0] + s->frame2->linesize[0] * (mov_y + h) + mov_x * s->bpp;
+        b1 = s->frame1->data[0] + s->frame1->linesize[0] * (start_y + h - 1) + start_x * s->bpp;
+        b2 = s->frame2->data[0] + s->frame2->linesize[0] * (start_y + h - 1) + start_x * s->bpp;
+        e2 = s->frame2->data[0] + s->frame2->linesize[0] * (mov_y + h - 1) + mov_x * s->bpp;
 
         if (type == 2) {
             for (int j = 0; j < h; j++) {