[FFmpeg-devel] [PATCH 1/4] avformat/aviobuf: Keep checksum_ptr consistent in avio_seek()

Andreas Rheinhardt ffmpegagent at gmail.com
Sat Jul 12 00:28:51 EEST 2025


From: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>

Otherwise it might be > buf_ptr in which case ffio_get_checksum()
could segfault (s->buf_ptr - s->checksum_ptr would be negative
which would be converted to something very big when converted
to unsigned for the update_checksum callback).

Fixes ticket #11233.

Reported-by: Du4t
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
---
 libavformat/aviobuf.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index 6a74c1ce68..9041280e77 100644
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -308,7 +308,7 @@ int64_t avio_seek(AVIOContext *s, int64_t offset, int whence)
         ctx->seek_count++;
         if (!s->write_flag)
             s->buf_end = s->buffer;
-        s->buf_ptr = s->buf_ptr_max = s->buffer;
+        s->checksum_ptr = s->buf_ptr = s->buf_ptr_max = s->buffer;
         s->pos = offset;
     }
     s->eof_reached = 0;
-- 
ffmpeg-codebot



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