From: Willy Tarreau <w@1wt.eu>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
"security@kernel.org" <security@kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Oleg Nesterov <oleg@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
Brad Spengler <spender@grsecurity.net>
Subject: Re: [PATCH v2] vfs: Tighten up linkat(..., AT_EMPTY_PATH)
Date: Thu, 22 Aug 2013 22:15:30 +0200 [thread overview]
Message-ID: <20130822201530.GL31117@1wt.eu> (raw)
In-Reply-To: <CALCETrU2xBykonV2N8bSysdycfZkCq_P5bUnrN5SjZo2_5dNrg@mail.gmail.com>
On Thu, Aug 22, 2013 at 01:10:43PM -0700, Andy Lutomirski wrote:
> What's the point of nd_jump_link anyway? The only way I can think of
> for a magic symlink in /proc to point to another symlink is to open a
> symlink with O_PATH | O_NOFOLLOW. Actually trying to use the
> resulting link in /proc results in -ELOOP. (Even just trying to open
> a normal symlink with O_NOFOLLOW and without O_PATH results in
> -ELOOP.)
It's not only that, it also supports sockets and pipes that you can access
via /proc/pid/fd and not via a real symlink which would try to open eg
"pipe:[23456]" instead of the real file. So you can't get rid of it
without breaking existing apps (starting with your shell for which
/dev/stdin is a link to /proc/self/fd/0 for example).
Willy
next prev parent reply other threads:[~2013-08-22 20:15 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-21 19:14 [PATCH v2] vfs: Tighten up linkat(..., AT_EMPTY_PATH) Andy Lutomirski
[not found] ` <CA+55aFxi-ps2f2M8xPhfbuQ0pToqupPrDsLi2+GPUK2sqdYfUw@mail.gmail.com>
[not found] ` <CALCETrW7+LcexA6v6RQDKhni_yJAduOmiSDneCpq3v8sPDvwUQ@mail.gmail.com>
2013-08-21 20:16 ` Willy Tarreau
2013-08-22 18:48 ` Linus Torvalds
2013-08-22 18:53 ` Willy Tarreau
2013-08-22 19:05 ` Andy Lutomirski
2013-08-22 19:23 ` Linus Torvalds
2013-08-22 20:10 ` Andy Lutomirski
2013-08-22 20:15 ` Willy Tarreau [this message]
2013-08-22 20:22 ` Andy Lutomirski
2013-08-22 20:44 ` Linus Torvalds
2013-08-22 20:48 ` Andy Lutomirski
2013-08-22 20:54 ` Linus Torvalds
2013-08-22 20:58 ` Andy Lutomirski
2013-08-23 1:07 ` Al Viro
2013-08-25 3:37 ` Al Viro
2013-08-25 7:26 ` Andy Lutomirski
2013-08-25 14:23 ` Al Viro
2013-08-25 17:04 ` Andy Lutomirski
2013-08-25 19:57 ` Linus Torvalds
2013-08-25 20:06 ` Al Viro
2013-08-25 20:23 ` Linus Torvalds
2013-08-26 17:37 ` Linus Torvalds
2013-08-26 18:07 ` Linus Torvalds
2013-08-26 18:11 ` Andy Lutomirski
2013-08-27 19:16 ` [RFC PATCH] fs: Add user_file_or_path_at and use it for truncate Andy Lutomirski
2013-08-27 19:32 ` Linus Torvalds
2013-08-27 20:28 ` Andy Lutomirski
2013-08-28 6:16 ` Al Viro
2013-08-28 16:24 ` Linus Torvalds
2013-08-28 19:04 ` Andy Lutomirski
2013-08-28 19:59 ` Al Viro
2013-08-28 21:07 ` Andy Lutomirski
2013-08-27 23:08 ` Al Viro
2013-08-27 23:13 ` Andy Lutomirski
2013-08-24 18:29 ` /proc/pid/fd && anon_inode_fops Oleg Nesterov
2013-08-24 21:24 ` Willy Tarreau
2013-08-25 5:23 ` Al Viro
2013-08-25 6:50 ` Willy Tarreau
2013-08-25 18:51 ` Linus Torvalds
2013-08-25 19:48 ` Oleg Nesterov
2013-08-25 20:05 ` Linus Torvalds
2013-08-26 15:33 ` Oleg Nesterov
2013-08-26 16:37 ` Oleg Nesterov
2013-08-26 17:54 ` [PATCH] proc: make proc_fd_permission() thread-friendly Oleg Nesterov
2013-08-26 18:09 ` Linus Torvalds
2013-08-26 19:35 ` Linus Torvalds
2013-08-26 20:20 ` Willy Tarreau
2013-08-27 15:05 ` Oleg Nesterov
2013-08-27 14:39 ` [PATCH 0/1] proc: make /proc/self point to thread Oleg Nesterov
2013-08-27 14:40 ` [PATCH 1/1] " Oleg Nesterov
2013-08-27 16:39 ` Linus Torvalds
2013-08-27 17:49 ` Oleg Nesterov
2013-08-27 18:15 ` Linus Torvalds
2013-08-27 18:28 ` Oleg Nesterov
[not found] ` <CALCETrXP-mYBPRon=0NzexW1FK1Qxz2+Bwv7-WeHBQpvW7ywRg@mail.gmail.com>
2013-08-27 15:45 ` [PATCH] proc: make proc_fd_permission() thread-friendly Oleg Nesterov
2013-08-26 18:32 ` Eric W. Biederman
2013-08-26 18:46 ` Oleg Nesterov
2013-08-26 18:56 ` Oleg Nesterov
2013-08-26 19:10 ` Eric W. Biederman
2013-08-27 14:53 ` Oleg Nesterov
2013-08-25 18:32 ` /proc/pid/fd && anon_inode_fops Linus Torvalds
2013-08-25 19:11 ` Al Viro
2013-08-25 19:17 ` Andy Lutomirski
2013-09-03 15:58 ` Pavel Machek
2013-08-25 15:45 ` Oleg Nesterov
[not found] ` <20130825051044.GY27005@ZenIV.linux.org.uk>
[not found] ` <20130825155348.GB25922@redhat.com>
[not found] ` <CALCETrXrtP2C+g=QeNWK4EMctmonW91kWoO1xmy7rDmEj__1Dw@mail.gmail.com>
[not found] ` <20130825174936.GA30957@redhat.com>
2013-08-25 17:55 ` [PATCH 0/1] anon_inodefs: forbid open via /proc Oleg Nesterov
2013-08-25 17:55 ` [PATCH 1/1] " Oleg Nesterov
2013-08-22 19:39 ` [PATCH v2] vfs: Tighten up linkat(..., AT_EMPTY_PATH) Willy Tarreau
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