From: Seth Forshee <seth.forshee@canonical.com>
To: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
devel@openvz.org, Serge Hallyn <serge.hallyn@canonical.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Jeff Layton <jlayton@poochiereds.net>,
"J. Bruce Fields" <bfields@fieldses.org>,
Andy Lutomirski <luto@amacapital.net>,
linux-security-module@vger.kernel.org,
linux-mtd@lists.infradead.org, selinux@tycho.nsa.gov,
linux-fsdevel@vger.kernel.org,
Konstantin Khorenko <khorenko@virtuozzo.com>,
Pavel Emelyanov <xemul@virtuozzo.com>
Subject: Re: [PATCH] fs: fix a posible leak of allocated superblock
Date: Tue, 15 Mar 2016 08:32:41 -0500 [thread overview]
Message-ID: <20160315133241.GA27754@ubuntu-xps13> (raw)
In-Reply-To: <1458043730-14296-1-git-send-email-ptikhomirov@virtuozzo.com>
On Tue, Mar 15, 2016 at 03:08:50PM +0300, Pavel Tikhomirov wrote:
> We probably need to fix superblock leak in patch (v4 "fs: Add user
> namesapace member to struct super_block"):
>
> Imagine posible code path in sget_userns: we iterate through
> type->fs_supers and do not find suitable sb, we drop sb_lock to
> allocate s and go to retry. After we dropped sb_lock some other
> task from different userns takes sb_lock, it is already in retry
> stage and has s allocated, so it puts its s in type->fs_supers
> list. So in retry we will find these sb in list and check it has
> a different userns, and finally we will return without freeing s.
>
> Signed-off-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Good catch.
Acked-by: Seth Forshee <seth.forshee@canonical.com>
next prev parent reply other threads:[~2016-03-15 13:32 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-23 20:16 [PATCH v4 0/7] Initial support for user namespace owned mounts Seth Forshee
2015-09-23 20:16 ` [PATCH v4 1/7] fs: Add user namesapace member to struct super_block Seth Forshee
2015-09-24 21:14 ` Eric W. Biederman
2015-09-25 12:54 ` Seth Forshee
2015-09-25 17:27 ` Eric W. Biederman
2016-03-15 12:08 ` [PATCH] fs: fix a posible leak of allocated superblock Pavel Tikhomirov
2016-03-15 13:32 ` Seth Forshee [this message]
2015-09-23 20:16 ` [PATCH v4 2/7] userns: Simpilify MNT_NODEV handling Seth Forshee
2015-09-23 20:16 ` [PATCH v4 3/7] fs: Verify access of user towards block device file when mounting Seth Forshee
2015-09-24 21:53 ` Eric W. Biederman
2015-09-25 12:48 ` Seth Forshee
2015-09-25 17:16 ` Eric W. Biederman
2015-09-25 17:39 ` Seth Forshee
2015-09-25 17:49 ` Eric W. Biederman
2015-09-23 20:16 ` [PATCH v4 4/7] fs: Limit file caps to the user namespace of the super block Seth Forshee
2015-09-24 21:59 ` Eric W. Biederman
2015-09-25 12:49 ` Seth Forshee
2015-09-25 17:57 ` Eric W. Biederman
2015-09-23 20:16 ` [PATCH v4 5/7] fs: Treat foreign mounts as nosuid Seth Forshee
2015-09-23 20:16 ` [PATCH v4 6/7] Smack: Add support for unprivileged mounts from user namespaces Seth Forshee
2015-09-24 22:16 ` Eric W. Biederman
2015-09-24 22:34 ` Casey Schaufler
2015-09-27 19:30 ` Eric W. Biederman
2015-09-28 19:45 ` Seth Forshee
2015-09-23 20:16 ` [PATCH v4 7/7] selinux: " Seth Forshee
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