[FFmpeg-cvslog] avcodec/flac_parser: avoid returning too negative number

[Paul B Mahol]

ffmpeg | branch: master | Paul B Mahol <onemda at gmail.com> | Thu Sep  8 09:59:09 2022 +0200| [cf2cf31805448dd11692313440a21821773a6128] | committer: Paul B Mahol

avcodec/flac_parser: avoid returning too negative number

If return value is very small parser code will assert.

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=cf2cf31805448dd11692313440a21821773a6128
---

 libavcodec/flac_parser.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/libavcodec/flac_parser.c b/libavcodec/flac_parser.c
index 5b3a4e6e67..bd91cc1a05 100644
--- a/libavcodec/flac_parser.c
+++ b/libavcodec/flac_parser.c
@@ -663,8 +663,11 @@ static int get_best_header(FLACParseContext *fpc, const uint8_t **poutbuf,
 
     /* Return the negative overread index so the client can compute pos.
        This should be the amount overread to the beginning of the child */
-    if (child)
-        return child->offset - flac_fifo_size(&fpc->fifo_buf);
+    if (child) {
+        int64_t offset = child->offset - flac_fifo_size(&fpc->fifo_buf);
+        if (offset > -(1 << 28))
+            return offset;
+    }
     return 0;
 }