[FFmpeg-cvslog] avcodec/gif: Fix lzw buffer size
Michael Niedermayer
git at videolan.org
Mon Jan 18 19:58:42 CET 2016
ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Mon Jan 18 19:20:03 2016 +0100| [03d83ba34b2070878909eae18dfac0f519503777] | committer: Michael Niedermayer
avcodec/gif: Fix lzw buffer size
Fixes out of array access
Fixes: aaa479088e6fb40b04837b3119f47b04/asan_heap-oob_e38c68_8576_9d653078b2470700e2834636f12ff557.tga
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=03d83ba34b2070878909eae18dfac0f519503777
---
libavcodec/gif.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/libavcodec/gif.c b/libavcodec/gif.c
index acdc0e1..6af1f4a 100644
--- a/libavcodec/gif.c
+++ b/libavcodec/gif.c
@@ -43,6 +43,7 @@ typedef struct GIFContext {
const AVClass *class;
LZWState *lzw;
uint8_t *buf;
+ int buf_size;
AVFrame *last_frame;
int flags;
uint32_t palette[AVPALETTE_COUNT]; ///< local reference palette for !pal8
@@ -174,7 +175,7 @@ static int gif_image_write_image(AVCodecContext *avctx,
bytestream_put_byte(bytestream, 0x08);
- ff_lzw_encode_init(s->lzw, s->buf, 2 * width * height,
+ ff_lzw_encode_init(s->lzw, s->buf, s->buf_size,
12, FF_LZW_GIF, put_bits);
ptr = buf + y_start*linesize + x_start;
@@ -231,7 +232,8 @@ FF_ENABLE_DEPRECATION_WARNINGS
s->transparent_index = -1;
s->lzw = av_mallocz(ff_lzw_encode_state_size);
- s->buf = av_malloc(avctx->width*avctx->height*2);
+ s->buf_size = avctx->width*avctx->height*2 + 1000;
+ s->buf = av_malloc(s->buf_size);
s->tmpl = av_malloc(avctx->width);
if (!s->tmpl || !s->buf || !s->lzw)
return AVERROR(ENOMEM);
@@ -321,6 +323,7 @@ static int gif_encode_close(AVCodecContext *avctx)
av_freep(&s->lzw);
av_freep(&s->buf);
+ s->buf_size = 0;
av_frame_free(&s->last_frame);
av_freep(&s->tmpl);
return 0;
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