From b5da848facd41169283d7bfe568b83bdfa7fc42e Mon Sep 17 00:00:00 2001 From: Alex Converse Date: Wed, 2 May 2012 12:08:03 -0700 Subject: [PATCH] motionpixels: Clip YUV values after applying a gradient. Prevents illegal reads on truncated and malformed input. CC: libav-stable@libav.org --- libavcodec/motionpixels.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/libavcodec/motionpixels.c b/libavcodec/motionpixels.c index 6151e6a114..8a3c870986 100644 --- a/libavcodec/motionpixels.c +++ b/libavcodec/motionpixels.c @@ -190,10 +190,13 @@ static void mp_decode_line(MotionPixelsContext *mp, GetBitContext *gb, int y) p = mp_get_yuv_from_rgb(mp, x - 1, y); } else { p.y += mp_gradient(mp, 0, mp_get_vlc(mp, gb)); + p.y = av_clip(p.y, 0, 31); if ((x & 3) == 0) { if ((y & 3) == 0) { p.v += mp_gradient(mp, 1, mp_get_vlc(mp, gb)); + p.v = av_clip(p.v, -32, 31); p.u += mp_gradient(mp, 2, mp_get_vlc(mp, gb)); + p.u = av_clip(p.u, -32, 31); mp->hpt[((y / 4) * mp->avctx->width + x) / 4] = p; } else { p.v = mp->hpt[((y / 4) * mp->avctx->width + x) / 4].v; @@ -217,9 +220,12 @@ static void mp_decode_frame_helper(MotionPixelsContext *mp, GetBitContext *gb) p = mp_get_yuv_from_rgb(mp, 0, y); } else { p.y += mp_gradient(mp, 0, mp_get_vlc(mp, gb)); + p.y = av_clip(p.y, 0, 31); if ((y & 3) == 0) { p.v += mp_gradient(mp, 1, mp_get_vlc(mp, gb)); + p.v = av_clip(p.v, -32, 31); p.u += mp_gradient(mp, 2, mp_get_vlc(mp, gb)); + p.u = av_clip(p.u, -32, 31); } mp->vpt[y] = p; mp_set_rgb_from_yuv(mp, 0, y, &p);