[FFmpeg-devel] [PATCH 2/2] avdevice/libopenh264dec: Increase array sizes, fix stack-buffer overread

[Andreas Rheinhardt]

av_image_copy() expects an array of four pointers and linesizes
according to its declaration; it currently only pointers that are
actually in use (depending upon the pixel format), but this might
change at any time. It has already happened for the linesizes in
d7bc52bf456deba0f32d9fe5c288ec441f1ebef5 and so increasing their
array fixes a stack-buffer overread.

This fixes a -Wstringop-overflow= and -Wstringop-overread warning
from GCC 11.2.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
---
 libavcodec/libopenh264dec.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/libavcodec/libopenh264dec.c b/libavcodec/libopenh264dec.c
index ea70a8e143..7f5e85402a 100644
--- a/libavcodec/libopenh264dec.c
+++ b/libavcodec/libopenh264dec.c
@@ -91,8 +91,8 @@ static int svc_decode_frame(AVCodecContext *avctx, void *data,
 {
     SVCContext *s = avctx->priv_data;
     SBufferInfo info = { 0 };
-    uint8_t* ptrs[3];
-    int ret, linesize[3];
+    uint8_t *ptrs[4] = { NULL };
+    int ret, linesize[4];
     AVFrame *avframe = data;
     DECODING_STATE state;
 #if OPENH264_VER_AT_LEAST(1, 7)
@@ -140,6 +140,7 @@ static int svc_decode_frame(AVCodecContext *avctx, void *data,
 
     linesize[0] = info.UsrData.sSystemBuffer.iStride[0];
     linesize[1] = linesize[2] = info.UsrData.sSystemBuffer.iStride[1];
+    linesize[3] = 0;
     av_image_copy(avframe->data, avframe->linesize, (const uint8_t **) ptrs, linesize, avctx->pix_fmt, avctx->width, avctx->height);
 
     avframe->pts     = info.uiOutYuvTimeStamp;
-- 
2.32.0