From: Ingo Molnar <mingo@kernel.org>
To: Djalal Harouni <tixxdz@opendz.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Kees Cook <keescook@chromium.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
"Serge E. Hallyn" <serge.hallyn@ubuntu.com>,
Cyrill Gorcunov <gorcunov@openvz.org>,
David Rientjes <rientjes@google.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>,
kernel-hardening@lists.openwall.com,
Djalal Harouni <tixxdz@gmail.com>
Subject: Re: [PATCH v2 0/9] procfs: protect /proc/<pid>/* files with file->f_cred
Date: Thu, 3 Oct 2013 08:22:56 +0200 [thread overview]
Message-ID: <20131003062256.GD25345@gmail.com> (raw)
In-Reply-To: <20131002181257.GA2485@dztty>
* Djalal Harouni <tixxdz@opendz.org> wrote:
> * You can't do it for /proc/*/stat otherwise you will break userspace
> "ps"..., ps must access /proc/1/stat etc... so the proposed solution
> will work without any side effect.
The thing is, returning -EINVAL is not the only way to reject access to
privileged information!
In the /proc/1/stat case a compatibility quirk can solve the problem:
create a special 'dummy' process inode for invalid accesses and give it to
ps, with all fields present but zero.
> And for /proc/*/maps you will perhaps break glibc under certain
> situations... so just hold it for the moment and test it
> later. There have been reports in the past about it.
Same deal: just create a dummy compat-quirk maps inode with constant, zero
information contents to placate old user-space:
00000000-00000000 ---p 00000000 00:00 0
[ Or whatever line is needed to minimally not break old userspace. ]
But don't leak privileged information!
( Maybe add a CONFIG_PROC_FS_COMPAT_QUIRKS Kconfig option, default-y for
now, that new/sane userspace can turn off. )
Thanks,
Ingo
next prev parent reply other threads:[~2013-10-03 6:23 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-01 20:26 Djalal Harouni
2013-10-01 20:26 ` [PATCH v2 1/9] procfs: add proc_same_open_cred() to check if the cred have changed Djalal Harouni
2013-10-01 20:26 ` [PATCH v2 2/9] procfs: add proc_allow_access() to check if file's opener may access task Djalal Harouni
2013-10-02 1:36 ` Andy Lutomirski
2013-10-02 14:55 ` Djalal Harouni
2013-10-02 16:44 ` Andy Lutomirski
2013-10-03 14:36 ` Djalal Harouni
2013-10-03 15:12 ` Andy Lutomirski
2013-10-03 19:29 ` Djalal Harouni
2013-10-03 19:37 ` Andy Lutomirski
2013-10-03 20:13 ` Djalal Harouni
2013-10-03 21:09 ` Andy Lutomirski
2013-10-04 8:59 ` Djalal Harouni
2013-10-04 15:40 ` Andy Lutomirski
2013-10-04 18:23 ` Djalal Harouni
2013-10-04 18:34 ` Andy Lutomirski
2013-10-04 19:11 ` Djalal Harouni
2013-10-04 19:16 ` Andy Lutomirski
2013-10-04 19:27 ` Djalal Harouni
2013-10-04 19:32 ` Andy Lutomirski
2013-10-04 19:41 ` Djalal Harouni
2013-10-04 22:17 ` Andy Lutomirski
2013-10-04 22:55 ` Eric W. Biederman
2013-10-04 22:59 ` Andy Lutomirski
2013-10-04 23:08 ` Andy Lutomirski
2013-10-05 0:35 ` Eric W. Biederman
2013-10-09 10:35 ` Djalal Harouni
2013-10-05 13:23 ` Djalal Harouni
2013-10-07 21:41 ` Andy Lutomirski
2013-10-09 10:54 ` Djalal Harouni
2013-10-09 11:15 ` Djalal Harouni
2013-10-09 17:27 ` Andy Lutomirski
2013-10-13 10:18 ` Djalal Harouni
2013-10-01 20:26 ` [PATCH v2 3/9] procfs: Document the proposed solution to protect procfs entries Djalal Harouni
2013-10-01 20:26 ` [PATCH v2 4/9] procfs: make /proc/*/{stack,syscall} 0400 Djalal Harouni
2013-10-01 20:26 ` [PATCH v2 5/9] procfs: make /proc entries that use seq files able to access file->f_cred Djalal Harouni
2013-10-01 20:26 ` [PATCH v2 6/9] procfs: add permission checks on the file's opener of /proc/*/stat Djalal Harouni
2013-10-02 1:39 ` Andy Lutomirski
2013-10-02 15:14 ` Djalal Harouni
2013-10-02 16:46 ` Andy Lutomirski
2013-10-02 19:00 ` Djalal Harouni
2013-10-01 20:26 ` [PATCH v2 7/9] procfs: add permission checks on the file's opener of /proc/*/personality Djalal Harouni
2013-10-01 20:26 ` [PATCH v2 8/9] procfs: improve permission checks on /proc/*/stack Djalal Harouni
2013-10-01 20:26 ` [PATCH v2 9/9] procfs: improve permission checks on /proc/*/syscall Djalal Harouni
2013-10-02 1:40 ` [PATCH v2 0/9] procfs: protect /proc/<pid>/* files with file->f_cred Andy Lutomirski
2013-10-02 14:37 ` Djalal Harouni
2013-10-02 16:51 ` Andy Lutomirski
2013-10-02 17:48 ` Kees Cook
2013-10-02 18:00 ` Andy Lutomirski
2013-10-02 18:07 ` Kees Cook
2013-10-03 23:14 ` Julien Tinnes
2013-10-02 18:26 ` Djalal Harouni
2013-10-02 18:41 ` Djalal Harouni
2013-10-02 18:22 ` Djalal Harouni
2013-10-02 18:35 ` Kees Cook
2013-10-02 18:48 ` Djalal Harouni
2013-10-02 19:43 ` Kees Cook
2013-10-03 6:12 ` Ingo Molnar
2013-10-03 12:29 ` Djalal Harouni
2013-10-03 15:15 ` Andy Lutomirski
2013-10-03 15:40 ` Djalal Harouni
2013-10-03 15:50 ` Andy Lutomirski
2013-10-03 18:37 ` Djalal Harouni
2013-10-04 9:05 ` Djalal Harouni
2013-10-02 18:12 ` Djalal Harouni
2013-10-03 6:22 ` Ingo Molnar [this message]
2013-10-03 12:56 ` Djalal Harouni
2013-10-03 13:39 ` Ingo Molnar
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