From: Andy Lutomirski <luto@amacapital.net>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Jann Horn <jann@thejh.net>, Michal Hocko <mhocko@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux Containers <containers@lists.linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Linux FS Devel <linux-fsdevel@vger.kernel.org>
Subject: Re: [REVIEW][PATCH] exec: Don't exec files the userns root can not read.
Date: Wed, 19 Oct 2016 08:30:14 -0700 [thread overview]
Message-ID: <CALCETrU4SZYUEPrv4JkpUpA+0sZ=EirZRftRDp+a5hce5E7HgA@mail.gmail.com> (raw)
In-Reply-To: <87k2d5nytz.fsf_-_@xmission.com>
On Tue, Oct 18, 2016 at 2:15 PM, Eric W. Biederman
<ebiederm@xmission.com> wrote:
>
> When the user namespace support was merged the need to prevent
> ptracing an executable that is not readable was overlooked.
Before getting too excited about this fix, isn't there a much bigger
hole that's been there forever? Simply ptrace yourself, exec the
program, and then dump the program out. A program that really wants
to be unreadable should have a stub: the stub is setuid and readable,
but all the stub does is to exec the real program, and the real
program should have mode 0500 or similar.
ISTM the "right" check would be to enforce that the program's new
creds can read the program, but that will break backwards
compatibility.
--Andy
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next prev parent reply other threads:[~2016-10-19 15:30 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-17 16:39 [REVIEW][PATCH] mm: Add a user_ns owner to mm_struct and fix ptrace_may_access Eric W. Biederman
2016-10-17 17:25 ` Jann Horn
2016-10-17 17:33 ` Eric W. Biederman
2016-10-18 13:50 ` Michal Hocko
2016-10-18 13:57 ` Jann Horn
2016-10-18 14:56 ` Eric W. Biederman
2016-10-18 15:05 ` Jann Horn
2016-10-18 15:35 ` Eric W. Biederman
2016-10-18 19:12 ` Jann Horn
2016-10-18 21:07 ` Eric W. Biederman
2016-10-18 21:15 ` [REVIEW][PATCH] exec: Don't exec files the userns root can not read Eric W. Biederman
2016-10-19 6:13 ` Amir Goldstein
2016-10-19 13:33 ` Eric W. Biederman
2016-10-19 17:04 ` Eric W. Biederman
2016-10-19 15:30 ` Andy Lutomirski [this message]
2016-10-19 16:52 ` Eric W. Biederman
2016-10-19 17:29 ` Jann Horn
2016-10-19 17:32 ` Andy Lutomirski
2016-10-19 17:55 ` Eric W. Biederman
2016-10-19 18:38 ` Andy Lutomirski
2016-10-19 21:26 ` Eric W. Biederman
2016-10-19 23:17 ` Andy Lutomirski
2016-11-17 17:02 ` [REVIEW][PATCH 0/3] Fixing ptrace vs exec vs userns interactions Eric W. Biederman
2016-11-17 17:05 ` [REVIEW][PATCH 1/3] ptrace: Capture the ptracer's creds not PT_PTRACE_CAP Eric W. Biederman
2016-11-17 23:14 ` Kees Cook
2016-11-18 18:56 ` Eric W. Biederman
2016-11-17 23:27 ` Andy Lutomirski
2016-11-17 23:44 ` Eric W. Biederman
2016-11-17 17:08 ` [REVIEW][PATCH 2/3] exec: Don't allow ptracing an exec of an unreadable file Eric W. Biederman
2016-11-17 20:47 ` Willy Tarreau
2016-11-17 21:07 ` Kees Cook
2016-11-17 21:32 ` Willy Tarreau
2016-11-17 21:51 ` Eric W. Biederman
2016-11-17 22:50 ` [REVIEW][PATCH 2/3] ptrace: Don't allow accessing an undumpable mm Eric W. Biederman
2016-11-17 23:17 ` Kees Cook
2016-11-17 23:28 ` [REVIEW][PATCH 2/3] exec: Don't allow ptracing an exec of an unreadable file Andy Lutomirski
2016-11-17 23:29 ` Andy Lutomirski
2016-11-17 23:55 ` Eric W. Biederman
2016-11-18 0:10 ` Andy Lutomirski
2016-11-18 0:35 ` Eric W. Biederman
2016-11-17 17:10 ` [REVIEW][PATCH 3/3] exec: Ensure mm->user_ns contains the execed files Eric W. Biederman
2016-11-19 7:17 ` [REVIEW][PATCH 0/3] Fixing ptrace vs exec vs userns interactions Willy Tarreau
2016-11-19 9:28 ` Willy Tarreau
2016-11-19 9:33 ` Willy Tarreau
2016-11-19 18:44 ` Eric W. Biederman
2016-11-19 18:35 ` Eric W. Biederman
2016-11-19 18:37 ` Eric W. Biederman
2016-10-19 18:36 ` [REVIEW][PATCH] exec: Don't exec files the userns root can not read Andy Lutomirski
2016-10-18 18:06 ` [REVIEW][PATCH] mm: Add a user_ns owner to mm_struct and fix ptrace_may_access Michal Hocko
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