[FFmpeg-devel] [PATCH 2/2] avcodec/arbc: Use ff_reget_buffer()

[Michael Niedermayer]

Fixes: Timeout (20sec -> 0.5sec)
Fixes: 16404/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ARBC_fuzzer-5660216355454976

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/arbc.c | 21 +++++++--------------
 1 file changed, 7 insertions(+), 14 deletions(-)

diff --git a/libavcodec/arbc.c b/libavcodec/arbc.c
index 06970f140b..f0de50e243 100644
--- a/libavcodec/arbc.c
+++ b/libavcodec/arbc.c
@@ -136,15 +136,9 @@ static int decode_frame(AVCodecContext *avctx, void *data,
     if (7 * nb_segments > bytestream2_get_bytes_left(&s->gb))
         return AVERROR_INVALIDDATA;
 
-    if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
+    if ((ret = ff_reget_buffer(avctx, s->prev_frame)) < 0)
         return ret;
 
-    if (s->prev_frame->data[0]) {
-        ret = av_frame_copy(frame, s->prev_frame);
-        if (ret < 0)
-            return ret;
-    }
-
     for (int i = 0; i < nb_segments; i++) {
         int resolution_flag;
         int fill;
@@ -161,19 +155,18 @@ static int decode_frame(AVCodecContext *avctx, void *data,
         resolution_flag = bytestream2_get_byte(&s->gb);
 
         if (resolution_flag & 0x10)
-            prev_pixels -= fill_tileX(avctx, 1024, 1024, fill, frame);
+            prev_pixels -= fill_tileX(avctx, 1024, 1024, fill, s->prev_frame);
         if (resolution_flag & 0x08)
-            prev_pixels -= fill_tileX(avctx, 256, 256, fill, frame);
+            prev_pixels -= fill_tileX(avctx, 256, 256, fill, s->prev_frame);
         if (resolution_flag & 0x04)
-            prev_pixels -= fill_tileX(avctx, 64, 64, fill, frame);
+            prev_pixels -= fill_tileX(avctx, 64, 64, fill, s->prev_frame);
         if (resolution_flag & 0x02)
-            prev_pixels -= fill_tileX(avctx, 16, 16, fill, frame);
+            prev_pixels -= fill_tileX(avctx, 16, 16, fill, s->prev_frame);
         if (resolution_flag & 0x01)
-            prev_pixels -= fill_tile4(avctx, fill, frame);
+            prev_pixels -= fill_tile4(avctx, fill, s->prev_frame);
     }
 
-    av_frame_unref(s->prev_frame);
-    if ((ret = av_frame_ref(s->prev_frame, frame)) < 0)
+    if ((ret = av_frame_ref(frame, s->prev_frame)) < 0)
         return ret;
 
     frame->pict_type = prev_pixels <= 0 ? AV_PICTURE_TYPE_I : AV_PICTURE_TYPE_P;
-- 
2.23.0