From: "Alexander Ivanov" <amivanov@fastmail.com>
To: linux-security-module@vger.kernel.org
Subject: Denying access from sb_umount issue
Date: Mon, 27 Jan 2020 12:34:05 -0800 [thread overview]
Message-ID: <9e7ccbf8-e640-49b1-8e9c-ffa330b0feef@www.fastmail.com> (raw)
The lsm module implementes sb_umount() hook to disable lazy umounts. When access is denied, all consecutive umounts fail. It looks like mount reference count is messed up when sb_umount() return -EPERM. Is it possible that umount syscall assumes do_umount() touches those references and it calls
dput(path.dentry);
mntput_no_expire(mnt);
regardless of what do_mount() returns?
Thanks,
--Alex
next reply other threads:[~2020-01-27 20:33 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-27 20:34 Alexander Ivanov [this message]
2020-01-27 20:58 ` Denying access from sb_umount issue James Morris
2020-01-27 21:10 ` Alexander Ivanov
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