From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kHoBv-0003LY-8U for barebox@lists.infradead.org; Mon, 14 Sep 2020 13:06:44 +0000 From: Sascha Hauer Date: Mon, 14 Sep 2020 15:06:37 +0200 Message-Id: <20200914130640.21416-1-s.hauer@pengutronix.de> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 1/4] fs: don't free device in remove callback To: Barebox List Cc: Ahmad Fatoum From: Ahmad Fatoum The probe doesn't allocate the device, so remove shouldn't free it either. This fixes a use-after-free on barebox shutdown: Iterating over the list of devices requires that remove callbacks don't remove the devices. This happened to work so far, because apparently not much new allocations are going on during barebox shutdown, but let's do it right. Signed-off-by: Ahmad Fatoum --- fs/fs.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/fs/fs.c b/fs/fs.c index e04cadfe5d..30b835e265 100644 --- a/fs/fs.c +++ b/fs/fs.c @@ -679,7 +679,6 @@ static void fs_remove(struct device_d *dev) mntput(fsdev->vfsmount.parent); free(fsdev->backingstore); - free(fsdev); } struct bus_type fs_bus = { @@ -759,10 +758,18 @@ static void init_super(struct super_block *sb) static int fsdev_umount(struct fs_device_d *fsdev) { + int ret; + if (fsdev->vfsmount.ref) return -EBUSY; - return unregister_device(&fsdev->dev); + ret = unregister_device(&fsdev->dev); + if (ret) + return ret; + + free(fsdev); + + return 0; } /** -- 2.28.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox