From: Alexey Gladkov <gladkov.alexey@gmail.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kees Cook <keescook@chromium.org>,
Andrew Lutomirski <luto@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
LSM List <linux-security-module@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Akinobu Mita <akinobu.mita@gmail.com>,
Oleg Nesterov <oleg@redhat.com>,
Jeff Layton <jlayton@poochiereds.net>,
Ingo Molnar <mingo@kernel.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Daniel Micay <danielmicay@gmail.com>,
Jonathan Corbet <corbet@lwn.net>,
"J. Bruce Fields" <bfields@fieldses.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Solar Designer <solar@openwall.com>,
"Dmitry V. Levin" <ldv@altlinux.org>,
Djalal Harouni <tixxdz@gmail.com>
Subject: Re: [PATCH v5 5/7] proc: instantiate only pids that we can ptrace on 'limit_pids=1' mount option
Date: Mon, 14 May 2018 10:29:08 +0200 [thread overview]
Message-ID: <20180514082908.GA28179@comp-core-i7-2640m-0182e6> (raw)
In-Reply-To: <CA+55aFxYwH6dw=bsQJHEgkM_iZfVNerqn+RAXrrY2iufJag6Qw@mail.gmail.com>
On Fri, May 11, 2018 at 09:45:33AM -0700, Linus Torvalds wrote:
> On Fri, May 11, 2018 at 2:46 AM Alexey Gladkov <gladkov.alexey@gmail.com>
> wrote:
>
> > + /* Limit procfs to only ptracable tasks */
> > + if (limit_pids == PROC_LIMIT_PIDS_PTRACE) {
> > + cond_resched();
> > + if (!has_pid_permissions(fs_info, task,
> HIDEPID_NO_ACCESS))
> > + goto out_put_task;
> > + }
>
> Where did that "cond_resched()" come from? That doesn't seem to make a lot
> of sense.
This call came along with has_pid_permissions from proc_pid_readdir [1]. It
seems to me that proc_pid_readdir and proc_pid_lookup should act in a
similar way in this case.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=3ba4bceef23206349d4130ddf140819b365de7c8
--
Rgrds, legion
prev parent reply other threads:[~2018-05-14 8:29 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-11 9:36 [PATCH v5 5/7] proc: instantiate only pids that we can ptrace on 'limit_pids=1' mount option Alexey Gladkov
2018-05-11 16:09 ` Randy Dunlap
2018-05-14 8:34 ` Alexey Gladkov
2018-05-11 16:45 ` Linus Torvalds
2018-05-14 8:29 ` Alexey Gladkov [this message]
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