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: [email protected] Reported-by: Qu Wenruo <[email protected]> Signed-off-by: Max Reitz <[email protected]> --- block/blkdebug.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/block/blkdebug.c b/block/blkdebug.c index a5196e8..6166d6a 100644 --- a/block/blkdebug.c +++ b/block/blkdebug.c @@ -840,9 +840,13 @@ 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(); -- 2.9.4
