From de81d72d3d13a19edf4d461be3b0f5a877be0234 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Tue, 13 Jun 2017 19:20:05 +0200 Subject: blkdebug: Catch bs->exact_filename overflow The bs->exact_filename field may not be sufficient to store the full blkdebug node filename. In this case, we should not generate a filename at all instead of an unusable one. Cc: qemu-stable@nongnu.org Reported-by: Qu Wenruo Signed-off-by: Max Reitz Message-id: 20170613172006.19685-2-mreitz@redhat.com Reviewed-by: Alberto Garcia Reviewed-by: Stefan Hajnoczi Signed-off-by: Max Reitz --- block/blkdebug.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/block/blkdebug.c b/block/blkdebug.c index 6431962..a1b24b9 100644 --- a/block/blkdebug.c +++ b/block/blkdebug.c @@ -839,9 +839,13 @@ static void blkdebug_refresh_filename(BlockDriverState *bs, QDict *options) } if (!force_json && bs->file->bs->exact_filename[0]) { - snprintf(bs->exact_filename, sizeof(bs->exact_filename), - "blkdebug:%s:%s", s->config_file ?: "", - bs->file->bs->exact_filename); + int ret = snprintf(bs->exact_filename, sizeof(bs->exact_filename), + "blkdebug:%s:%s", s->config_file ?: "", + bs->file->bs->exact_filename); + if (ret >= sizeof(bs->exact_filename)) { + /* An overflow makes the filename unusable, so do not report any */ + bs->exact_filename[0] = 0; + } } opts = qdict_new(); -- cgit v1.1