From: Aleksa Sarai <cyphar@cyphar.com>
To: David Laight <David.Laight@ACULAB.COM>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
David Howells <dhowells@redhat.com>,
Eric Biederman <ebiederm@xmission.com>,
stable <stable@vger.kernel.org>,
Christian Brauner <christian.brauner@ubuntu.com>,
Serge Hallyn <serge@hallyn.com>,
"dev@opencontainers.org" <dev@opencontainers.org>,
Linux Containers <containers@lists.linux-foundation.org>,
Linux API <linux-api@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH RFC 0/1] mount: universally disallow mounting over symlinks
Date: Thu, 2 Jan 2020 20:09:20 +1100 [thread overview]
Message-ID: <20200102090920.gmvq45gqopbzmrgk@yavin.dot.cyphar.com> (raw)
In-Reply-To: <e1066da936244de99e7ee827695d6583@AcuMS.aculab.com>
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On 2020-01-02, David Laight <David.Laight@ACULAB.COM> wrote:
> From: Aleksa Sarai
> > Sent: 30 December 2019 08:32
> ...
> > I'm not sure I agree -- as I mentioned in my other mail, re-opening
> > through /proc/self/fd/$n works *very* well and has for a long time (in
> > fact, both LXC and runc depend on this working).
>
> I thought it was marginally broken because it is followed as a symlink?
> On, for example, NetBSD /proc/<n>/fd/<n> is a real reference to the
> filesystem inode and can be used to link the file back into the filesystem
> if all the directory entries have been removed.
That is also the case on Linux. It (strictly speaking) isn't a symlink
in the normal sense of the word, it's a magic-link (nd_jump_link
switches the nd->path to the actual 'struct file' in the case of
/proc/self/fd/$n).
--
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>
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next prev parent reply other threads:[~2020-01-02 9:09 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-30 5:20 [PATCH RFC 0/1] mount: universally disallow mounting over symlinks Aleksa Sarai
2019-12-30 5:20 ` [PATCH RFC 1/1] " Aleksa Sarai
2019-12-30 7:34 ` Linus Torvalds
2019-12-30 8:28 ` Aleksa Sarai
2020-01-08 4:39 ` Andy Lutomirski
2019-12-30 5:44 ` [PATCH RFC 0/1] " Al Viro
2019-12-30 5:49 ` Aleksa Sarai
2019-12-30 7:29 ` Aleksa Sarai
2019-12-30 7:53 ` Linus Torvalds
2019-12-30 8:32 ` Aleksa Sarai
2020-01-02 8:58 ` David Laight
2020-01-02 9:09 ` Aleksa Sarai [this message]
2020-01-01 0:43 ` Al Viro
2020-01-01 0:54 ` Al Viro
2020-01-01 3:08 ` Al Viro
2020-01-01 14:44 ` Aleksa Sarai
2020-01-01 23:40 ` Al Viro
2020-01-02 3:59 ` Aleksa Sarai
2020-01-03 1:49 ` Al Viro
2020-01-04 4:46 ` Ian Kent
2020-01-08 3:13 ` Al Viro
2020-01-08 3:54 ` Linus Torvalds
2020-01-08 21:34 ` Al Viro
2020-01-10 0:08 ` Linus Torvalds
2020-01-10 4:15 ` Al Viro
2020-01-10 5:03 ` Linus Torvalds
2020-01-10 6:20 ` Ian Kent
2020-01-12 21:33 ` Al Viro
2020-01-13 2:59 ` Ian Kent
2020-01-14 0:25 ` Ian Kent
2020-01-14 4:39 ` Al Viro
2020-01-14 5:01 ` Ian Kent
2020-01-14 5:59 ` Ian Kent
2020-01-10 21:07 ` Aleksa Sarai
2020-01-14 4:57 ` Al Viro
2020-01-14 5:12 ` Al Viro
2020-01-14 20:01 ` Aleksa Sarai
2020-01-15 14:25 ` Al Viro
2020-01-15 14:29 ` Aleksa Sarai
2020-01-15 14:34 ` Aleksa Sarai
2020-01-15 14:48 ` Al Viro
2020-01-15 13:57 ` Aleksa Sarai
2020-01-19 3:14 ` [RFC][PATCHSET][CFT] pathwalk cleanups and fixes Al Viro
2020-01-19 14:33 ` Ian Kent
2020-01-10 23:19 ` [PATCH RFC 0/1] mount: universally disallow mounting over symlinks Al Viro
2020-01-13 1:48 ` Ian Kent
2020-01-13 3:54 ` Al Viro
2020-01-13 6:00 ` Ian Kent
2020-01-13 6:03 ` Ian Kent
2020-01-13 13:30 ` Al Viro
2020-01-14 7:25 ` Ian Kent
2020-01-14 12:17 ` Ian Kent
2020-01-04 5:52 ` Andy Lutomirski
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