From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57520) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dKpUH-0002cX-MS for qemu-devel@nongnu.org; Tue, 13 Jun 2017 13:20:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dKpUG-00010V-Q4 for qemu-devel@nongnu.org; Tue, 13 Jun 2017 13:20:17 -0400 From: Max Reitz Date: Tue, 13 Jun 2017 19:20:05 +0200 Message-Id: <20170613172006.19685-2-mreitz@redhat.com> In-Reply-To: <20170613172006.19685-1-mreitz@redhat.com> References: <20170613172006.19685-1-mreitz@redhat.com> Subject: [Qemu-devel] [PATCH 1/2] blkdebug: Catch bs->exact_filename overflow List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: qemu-devel@nongnu.org, Max Reitz , Kevin Wolf , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= 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 --- 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