From: Linus Torvalds <torvalds@linux-foundation.org>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: David Laight <David.Laight@aculab.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"Serge E. Hallyn" <serge@hallyn.com>
Subject: Re: [PATCH 3/4] proc: Point /proc/net at /proc/thread-self/net instead of /proc/self/net
Date: Thu, 29 Sep 2022 12:00:59 -0700 [thread overview]
Message-ID: <CAHk-=wizrMKtFxtK-5b-RmC2T562A8iHSYpnAygu__U-HcG_3A@mail.gmail.com> (raw)
In-Reply-To: <YzXo/DIwq65ypHNH@ZenIV>
On Thu, Sep 29, 2022 at 11:50 AM Al Viro <viro@zeniv.linux.org.uk> wrote:
>
> What do you mean? Lookup on "net" in /proc returning what, exactly?
Returning the same directory as "thread-self/net", just not with a
symlink so that Apparmor doesn't get to mess things up..
> What would that dentry have for ->d_parent?
In a perfect world, I think it should act like a dynamic bind mount
(where the "dynamic" part is that thread-self part, and the parent
would be /proc.
That said, I think this is all a hack to deal with an Apparmor bug, so
I don't think we need perfect. Right now it's a symlink, so the parent
is the thread-self directory. I think that kind of magic jump would be
perfectly acceptable.
We have "magic jump" behavior in other /proc places, where the thing
*looks* like a symlink (ie readlink and friends just work), but the
lookup doesn't *actually* follow the symlink, it just looks things up
directly. IOW, all the /proc/<pid>/fd/<X> stuff.
So I think this would be just another case of that.
Linus
prev parent reply other threads:[~2022-09-29 19:01 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-29 15:22 [PATCH 3/4] proc: Point /proc/net at /proc/thread-self/net instead of /proc/self/net David Laight
2022-09-29 18:21 ` Linus Torvalds
2022-09-29 18:50 ` Al Viro
2022-09-29 19:00 ` Al Viro
2022-09-29 19:05 ` Linus Torvalds
2022-09-29 19:34 ` Al Viro
2022-09-29 21:13 ` Linus Torvalds
2022-09-29 21:21 ` Al Viro
2022-09-29 21:27 ` Al Viro
2022-09-29 21:31 ` Linus Torvalds
2022-09-29 21:15 ` Al Viro
2022-09-29 21:29 ` Linus Torvalds
2022-09-29 22:14 ` Eric W. Biederman
2022-09-29 22:48 ` [CFT][PATCH] proc: Update /proc/net to point at the accessing threads network namespace Eric W. Biederman
2022-09-29 23:38 ` Al Viro
2022-09-30 3:19 ` kernel test robot
2022-09-30 6:07 ` kernel test robot
2022-09-30 9:30 ` David Laight
2022-09-30 16:17 ` Eric W. Biederman
2022-09-30 21:28 ` David Laight
2022-10-01 23:11 ` Al Viro
2022-10-03 9:36 ` David Laight
2022-10-03 14:03 ` Al Viro
2022-10-03 17:07 ` Eric W. Biederman
2022-10-03 18:49 ` Al Viro
2022-10-04 8:53 ` David Laight
2022-10-05 13:10 ` [proc] 5336f1902b: BUG:KASAN:global-out-of-bounds_in_memchr kernel test robot
2022-09-29 19:00 ` Linus Torvalds [this message]
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