diff options
author | Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> | 2015-11-07 01:44:01 +0300 |
---|---|---|
committer | Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com> | 2015-11-07 15:15:14 +0300 |
commit | 3e8e1a660ea182111057d56ec1cfad2c62250f4c (patch) | |
tree | aed3cdcd453d018ed071f394aa5fd78ddd0118fb /libavcodec/pngdec.c | |
parent | db374790c75fa4ef947abcb5019fcf21d0b2de85 (diff) |
apng: use correct size for output buffer
The buffer needs s->bpp bytes, at maximum currently 10.
Assert that s->bpp is not larger.
This fixes a stack buffer overflow.
Reviewed-by: wm4 <nfxjfg@googlemail.com>
Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
Diffstat (limited to 'libavcodec/pngdec.c')
-rw-r--r-- | libavcodec/pngdec.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c index 689aa2b562..feb17630a2 100644 --- a/libavcodec/pngdec.c +++ b/libavcodec/pngdec.c @@ -1016,7 +1016,7 @@ static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s, for (x = s->x_offset; x < s->x_offset + s->cur_w; ++x, foreground += s->bpp, background += s->bpp) { size_t b; uint8_t foreground_alpha, background_alpha, output_alpha; - uint8_t output[4]; + uint8_t output[10]; // Since we might be blending alpha onto alpha, we use the following equations: // output_alpha = foreground_alpha + (1 - foreground_alpha) * background_alpha @@ -1056,6 +1056,8 @@ static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s, output_alpha = foreground_alpha + FAST_DIV255((255 - foreground_alpha) * background_alpha); + av_assert0(s->bpp <= 10); + for (b = 0; b < s->bpp - 1; ++b) { if (output_alpha == 0) { output[b] = 0; |