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| author | Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> | 2015-06-08 22:38:29 +0200 |
|---|---|---|
| committer | Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> | 2015-06-08 23:29:14 +0200 |
| commit | 6fdbaa2b7fb56623ab2163f861952bc1408c39b3 (patch) | |
| tree | 0183f9daa9d81e08ff2e88f4d3f9be0858434c70 /libavcodec/vp8.c | |
| parent | 1382add59df149193620ca0714ceac0929208c88 (diff) | |
| download | ffmpeg-6fdbaa2b7fb56623ab2163f861952bc1408c39b3.tar.gz | |
vp8: change mv_{min,max}.{x,y} type to int
If one of the dimensions is larger than 8176, s->mb_width or
s->mb_height is larger than 511, leading to an int16_t overflow of
s->mv_max.{x,y}. This then causes av_clip to be called with amin > amax.
Changing the type to int avoids the overflow and has no negative
effect, because s->mv_max is only used in clamp_mv for clipping.
Since mv_max.{x,y} is positive and mv_min.{x,y} negative, av_clip can't
increase the absolute value. The input to av_clip is an int16_t, and
thus the output fits into int16_t as well.
For additional safety, s->mv_{min,max}.{x,y} are clipped to int16_t range
before use.
Reviewed-by: Ronald S. Bultje <rsbultje@gmail.com>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Diffstat (limited to 'libavcodec/vp8.c')
| -rw-r--r-- | libavcodec/vp8.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/libavcodec/vp8.c b/libavcodec/vp8.c index dbba5687f2..becbb2c437 100644 --- a/libavcodec/vp8.c +++ b/libavcodec/vp8.c @@ -757,8 +757,10 @@ static int vp8_decode_frame_header(VP8Context *s, const uint8_t *buf, int buf_si static av_always_inline void clamp_mv(VP8Context *s, VP56mv *dst, const VP56mv *src) { - dst->x = av_clip(src->x, s->mv_min.x, s->mv_max.x); - dst->y = av_clip(src->y, s->mv_min.y, s->mv_max.y); + dst->x = av_clip(src->x, av_clip(s->mv_min.x, INT16_MIN, INT16_MAX), + av_clip(s->mv_max.x, INT16_MIN, INT16_MAX)); + dst->y = av_clip(src->y, av_clip(s->mv_min.y, INT16_MIN, INT16_MAX), + av_clip(s->mv_max.y, INT16_MIN, INT16_MAX)); } /** |