From: ebiederm@xmission.com (Eric W. Biederman)
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Greg KH <greg@kroah.com>, Peter Hurley <peter@hurleysoftware.com>,
Andy Lutomirski <luto@amacapital.net>,
security@debian.org, "security\@kernel.org" <security@kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>,
"security\@ubuntu.com \>\> security" <security@ubuntu.com>,
Serge Hallyn <serge.hallyn@ubuntu.com>, Willy Tarreau <w@1wt.eu>,
Aurelien Jarno <aurelien@aurel32.net>,
One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>,
Jann Horn <jann@thejh.net>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Jiri Slaby <jslaby@suse.com>, Florian Weimer <fw@deneb.enyo.de>,
Konstantin Khlebnikov <koct9i@gmail.com>
Subject: Re: [PATCH tty-next] devpts: Make each mount of devpts an independent filesystem.
Date: Thu, 02 Jun 2016 16:23:36 -0500 [thread overview]
Message-ID: <87a8j3thd3.fsf@x220.int.ebiederm.org> (raw)
In-Reply-To: <94ee92fa-b07b-af9f-c631-18e96a0a465c@zytor.com> (H. Peter Anvin's message of "Thu, 2 Jun 2016 13:36:55 -0700")
"H. Peter Anvin" <hpa@zytor.com> writes:
> On 06/02/16 13:22, Eric W. Biederman wrote:
>>
>> The problem with lookup_one_len_unlocked is that it still calls
>> inode_permission.
>>
>> As per previous discussions we don't want the path based permission
>> checks involved in that lookup.
>>
>
> Is it that we don't *want* it, or that we don't *need* it? In the
> latter case, we could just do whatever makes the code simpler, no?
We certainly don't need the permission check.
Keeping the permission check appears to introduce an inconsistency
between what make sense for the code to do and what the code actually
does that only matters once in a blue moon.
That weirdness will probably cause an issue for someone sometime that
will take forever to track down, because no one will be expecting it.
So in my opinion the code will be much more maintainable if we don't
include user visible behaviors that will violate peoples simple mental
model of how the code behaves.
Eric
next prev parent reply other threads:[~2016-06-02 21:35 UTC|newest]
Thread overview: 154+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <43AD2BA7-B594-4299-95F3-D86FD38AF21B@zytor.com>
[not found] ` <87egexpf4o.fsf@x220.int.ebiederm.org>
[not found] ` <CA+55aFw9Bg+Zh_T4zP487n3ieaxoMHgZ_nNJVdpSR4kQK9gQ9w@mail.gmail.com>
[not found] ` <1CB621EF-1647-463B-A144-D611DB150E15@zytor.com>
[not found] ` <20151208223135.GA8352@kroah.com>
[not found] ` <87oae0h2bo.fsf@x220.int.ebiederm.org>
[not found] ` <56677DE3.5040705@zytor.com>
[not found] ` <20151209012311.GA11794@kroah.com>
[not found] ` <84B136DF-55E4-476A-9CB2-062B15677EE5@zytor.com>
[not found] ` <20151209013859.GA12442@kroah.com>
[not found] ` <20151209083225.GA30452@1wt.eu>
2015-12-11 19:40 ` [PATCH] devpts: Sensible /dev/ptmx & force newinstance Eric W. Biederman
2015-12-11 20:50 ` Linus Torvalds
2015-12-11 21:03 ` Eric W. Biederman
2015-12-11 21:04 ` Al Viro
2015-12-11 21:11 ` Eric W. Biederman
2015-12-11 21:48 ` Andy Lutomirski
2015-12-11 22:07 ` H. Peter Anvin
2015-12-11 22:12 ` Andy Lutomirski
2015-12-11 22:18 ` H. Peter Anvin
2015-12-11 22:24 ` Andy Lutomirski
2015-12-11 22:29 ` H. Peter Anvin
2015-12-11 22:35 ` Eric W. Biederman
2015-12-11 22:52 ` Andy Lutomirski
2015-12-11 22:58 ` Jann Horn
2015-12-11 23:00 ` Andy Lutomirski
2015-12-11 23:07 ` H. Peter Anvin
2015-12-11 23:16 ` Andy Lutomirski
2015-12-11 23:30 ` H. Peter Anvin
2015-12-11 22:57 ` H. Peter Anvin
2015-12-14 19:47 ` Peter Hurley
2015-12-14 19:55 ` H. Peter Anvin
2015-12-19 21:13 ` Eric W. Biederman
2015-12-20 4:11 ` Eric W. Biederman
2015-12-20 4:35 ` H. Peter Anvin
2015-12-20 9:42 ` Eric W. Biederman
2015-12-21 22:03 ` Eric W. Biederman
2015-12-21 22:23 ` Linus Torvalds
2016-04-05 0:03 ` [PATCH 00/13] devpts: New instances for every mount Eric W. Biederman
2016-04-05 1:29 ` [PATCH 01/13] devpts: Teach /dev/ptmx to find the associated devpts via path lookup Eric W. Biederman
2016-04-05 1:29 ` [PATCH 02/13] devpts: More obvious check for the system devpts in pty allocation Eric W. Biederman
2016-04-05 1:29 ` [PATCH 03/13] devpts: Cleanup newinstance parsing Eric W. Biederman
2016-04-05 1:29 ` [PATCH 04/13] devpts: Stop rolling devpts_remount by hand in devpts_mount Eric W. Biederman
2016-04-05 1:29 ` [PATCH 05/13] devpts: Fail early (if appropriate) on overmount Eric W. Biederman
2016-04-05 1:29 ` [PATCH 06/13] devpts: Use the same default mode for both /dev/ptmx and dev/pts/ptmx Eric W. Biederman
2016-04-05 1:29 ` [PATCH 07/13] devpts: Move parse_mount_options into fill_super Eric W. Biederman
2016-04-05 1:29 ` [PATCH 08/13] devpts: Make devpts_kill_sb safe if fsi is NULL Eric W. Biederman
2016-04-05 1:29 ` [PATCH 09/13] devpts: Move the creation of /dev/pts/ptmx into fill_super Eric W. Biederman
2016-04-05 1:29 ` [PATCH 10/13] devpts: Simplify devpts_mount by using mount_nodev Eric W. Biederman
2016-04-05 1:29 ` [PATCH 11/13] vfs: Implement mount_super_once Eric W. Biederman
2016-04-05 1:29 ` [PATCH 12/13] devpts: Always return a distinct instance when mounting Eric W. Biederman
2016-04-05 1:29 ` [PATCH 13/13] devpts: Kill the DEVPTS_MULTIPLE_INSTANCE config option Eric W. Biederman
2016-04-05 2:54 ` [PATCH 01/13] devpts: Teach /dev/ptmx to find the associated devpts via path lookup Al Viro
2016-04-05 3:03 ` Al Viro
2016-04-08 18:54 ` Eric W. Biederman
2016-04-07 16:06 ` Linus Torvalds
2016-04-08 18:51 ` Eric W. Biederman
2016-04-08 19:05 ` Linus Torvalds
2016-04-08 20:05 ` Eric W. Biederman
2016-04-08 20:43 ` Andy Lutomirski
2016-04-08 21:29 ` Eric W. Biederman
2016-04-08 21:54 ` Linus Torvalds
2016-04-08 23:03 ` Eric W. Biederman
2016-04-08 21:56 ` Andy Lutomirski
2016-04-09 13:09 ` One Thousand Gnomes
2016-04-09 14:10 ` H. Peter Anvin
2016-04-09 14:45 ` Eric W. Biederman
2016-04-09 22:37 ` H. Peter Anvin
2016-04-10 0:01 ` Linus Torvalds
2016-04-10 0:06 ` H. Peter Anvin
2016-04-10 0:16 ` Linus Torvalds
2016-04-10 0:44 ` Andy Lutomirski
[not found] ` <CA+55aFzs00iDkYhvFCq=AZMVcNL0+oZT4SeimTeVurJq=5ZS3A@mail.gmail.com>
2016-04-11 14:48 ` H. Peter Anvin
2016-04-12 1:31 ` Al Viro
2016-04-11 20:12 ` Andy Lutomirski
2016-04-11 20:10 ` Eric W. Biederman
2016-04-11 20:16 ` H. Peter Anvin
2016-04-11 23:37 ` Eric W. Biederman
2016-04-12 0:01 ` Linus Torvalds
2016-04-12 0:10 ` Eric W. Biederman
2016-04-12 1:06 ` H. Peter Anvin
2016-04-12 1:18 ` Linus Torvalds
2016-04-12 1:23 ` Eric W. Biederman
2016-04-12 1:47 ` Al Viro
2016-04-12 1:34 ` Al Viro
2016-04-12 2:16 ` Eric W. Biederman
2016-04-12 17:44 ` Andy Lutomirski
2016-04-12 18:12 ` Linus Torvalds
2016-04-12 19:07 ` H. Peter Anvin
2016-04-15 15:34 ` [PATCH 01/16] devpts: Attempting to get it right Eric W. Biederman
2016-04-15 15:35 ` [PATCH 01/16] devpts: Use the same default mode for both /dev/ptmx and dev/pts/ptmx Eric W. Biederman
2016-04-15 15:35 ` [PATCH 02/16] devpts: Set the proper fops for /dev/pts/ptmx Eric W. Biederman
2016-04-15 15:35 ` [PATCH 03/16] vfs: Implement vfs_loopback_mount Eric W. Biederman
2016-04-15 15:35 ` [PATCH 04/16] devpts: Teach /dev/ptmx to automount the appropriate devpts via path lookup Eric W. Biederman
2016-04-15 22:03 ` Jann Horn
2016-04-19 18:46 ` Eric W. Biederman
2016-04-15 15:35 ` [PATCH 05/16] vfs: Allow unlink, and rename on expirable file mounts Eric W. Biederman
2016-04-15 15:35 ` [PATCH 06/16] devpts: More obvious check for the system devpts in pty allocation Eric W. Biederman
2016-04-15 15:35 ` [PATCH 07/16] devpts: Cleanup newinstance parsing Eric W. Biederman
2016-04-15 15:35 ` [PATCH 08/16] devpts: Stop rolling devpts_remount by hand in devpts_mount Eric W. Biederman
2016-04-15 15:35 ` [PATCH 09/16] devpts: Fail early (if appropriate) on overmount Eric W. Biederman
2016-04-15 15:35 ` [PATCH 10/16] devpts: Move parse_mount_options into fill_super Eric W. Biederman
2016-04-15 15:35 ` [PATCH 11/16] devpts: Make devpts_kill_sb safe if fsi is NULL Eric W. Biederman
2016-04-15 15:35 ` [PATCH 12/16] devpts: Move the creation of /dev/pts/ptmx into fill_super Eric W. Biederman
2016-04-15 15:35 ` [PATCH 13/16] devpts: Simplify devpts_mount by using mount_nodev Eric W. Biederman
2016-04-15 15:35 ` [PATCH 14/16] vfs: Implement mount_super_once Eric W. Biederman
2016-04-15 23:02 ` Linus Torvalds
2016-04-19 18:22 ` Eric W. Biederman
2016-04-19 18:47 ` H. Peter Anvin
2016-04-19 19:03 ` Eric W. Biederman
2016-04-19 19:25 ` H. Peter Anvin
2016-04-19 19:26 ` H. Peter Anvin
2016-04-20 3:27 ` Eric W. Biederman
2016-04-20 11:50 ` Austin S. Hemmelgarn
2016-04-20 16:12 ` H. Peter Anvin
2016-04-19 18:55 ` H. Peter Anvin
2016-04-19 23:29 ` Linus Torvalds
2016-04-20 1:24 ` Linus Torvalds
2016-04-20 1:37 ` H. Peter Anvin
2016-04-15 15:35 ` [PATCH 15/16] devpts: Always return a distinct instance when mounting Eric W. Biederman
2016-04-15 15:35 ` [PATCH 16/16] devpts: Kill the DEVPTS_MULTIPLE_INSTANCE config option Eric W. Biederman
2016-04-15 16:49 ` [PATCH 01/16] devpts: Attempting to get it right Andy Lutomirski
2016-04-15 20:43 ` Eric W. Biederman
2016-04-15 21:29 ` H. Peter Anvin
2016-04-19 19:00 ` Eric W. Biederman
2016-04-16 18:31 ` Linus Torvalds
2016-04-19 18:44 ` Does anyone care about a race free ptsname? Eric W. Biederman
2016-04-19 19:16 ` H. Peter Anvin
2016-04-19 20:32 ` Eric W. Biederman
2016-04-19 20:55 ` H. Peter Anvin
2016-04-19 20:42 ` Serge E. Hallyn
2016-04-19 23:23 ` Linus Torvalds
2016-04-19 23:39 ` H. Peter Anvin
2016-04-20 0:18 ` Linus Torvalds
2016-04-20 1:48 ` Serge E. Hallyn
2016-04-19 22:06 ` [PATCH 01/16] devpts: Attempting to get it right Eric W. Biederman
2016-04-19 23:35 ` Linus Torvalds
2016-04-20 0:24 ` Peter Hurley
2016-04-20 0:49 ` Peter Hurley
2016-04-20 3:04 ` [PATCH] devpts: Make each mount of devpts an independent filesystem Eric W. Biederman
2016-04-20 3:25 ` Al Viro
2016-04-20 3:43 ` Eric W. Biederman
2016-04-20 4:11 ` Al Viro
2016-04-20 4:21 ` Eric W. Biederman
2016-04-20 4:36 ` Konstantin Khlebnikov
2016-04-20 4:49 ` Linus Torvalds
2016-04-20 14:55 ` Eric W. Biederman
2016-04-20 15:34 ` Konstantin Khlebnikov
2016-04-20 15:50 ` Eric W. Biederman
2016-04-20 17:00 ` [PATCH v2] " Eric W. Biederman
[not found] ` <874mabt3df.fsf_-_@x220.int.ebiederm.org>
2016-05-06 19:04 ` [PATCH 1/1] " Eric W. Biederman
2016-05-06 19:35 ` [PATCH 0/1] devpts: Removing the need for pt_chown Greg KH
2016-05-06 19:45 ` Peter Hurley
2016-05-06 19:54 ` Greg KH
2016-06-02 15:29 ` [PATCH tty-next] devpts: Make each mount of devpts an independent filesystem Eric W. Biederman
2016-06-02 18:57 ` Linus Torvalds
2016-06-02 20:22 ` Eric W. Biederman
2016-06-02 20:36 ` H. Peter Anvin
2016-06-02 21:23 ` Eric W. Biederman [this message]
2016-06-02 21:44 ` Linus Torvalds
2016-04-11 23:49 ` [PATCH 01/13] devpts: Teach /dev/ptmx to find the associated devpts via path lookup Eric W. Biederman
2016-04-12 0:08 ` Linus Torvalds
2016-04-12 0:22 ` Eric W. Biederman
2016-04-12 0:50 ` Linus Torvalds
2016-04-11 20:05 ` Eric W. Biederman
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