From: Bastian Blank <bastian@waldi.eu.org>
To: "Serge E. Hallyn" <serge@hallyn.com>
Cc: containers@lists.linux-foundation.org,
kernel list <linux-kernel@vger.kernel.org>,
LSM <linux-security-module@vger.kernel.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Kees Cook <kees.cook@canonical.com>,
Alexey Dobriyan <adobriyan@gmail.com>,
Michael Kerrisk <mtk.manpages@gmail.com>
Subject: Re: [PATCH 05/08] Allow ptrace from non-init user namespaces
Date: Fri, 14 Jan 2011 15:46:09 +0100 [thread overview]
Message-ID: <20110114144608.GA20945@wavehammer.waldi.eu.org> (raw)
In-Reply-To: <20110111064439.GF27515@mail.hallyn.com>
This mail did not show up in my inbox, even if I'm listed as receipient.
I only got a copy via the mailinglist.
On Tue, Jan 11, 2011 at 06:44:39AM +0000, Serge E. Hallyn wrote:
> diff --git a/kernel/ptrace.c b/kernel/ptrace.c
> index 99bbaa3..ec7605d 100644
> --- a/kernel/ptrace.c
> +++ b/kernel/ptrace.c
> @@ -134,21 +134,24 @@ int __ptrace_may_access(struct task_struct *task, unsigned int mode)
> return 0;
> rcu_read_lock();
> tcred = __task_cred(task);
> - if ((cred->uid != tcred->euid ||
> - cred->uid != tcred->suid ||
> - cred->uid != tcred->uid ||
> - cred->gid != tcred->egid ||
> - cred->gid != tcred->sgid ||
> - cred->gid != tcred->gid) &&
> - !capable(CAP_SYS_PTRACE)) {
> - rcu_read_unlock();
> - return -EPERM;
> - }
> + if (cred->user->user_ns == tcred->user->user_ns &&
> + (cred->uid == tcred->euid &&
> + cred->uid == tcred->suid &&
> + cred->uid == tcred->uid &&
> + cred->gid == tcred->egid &&
> + cred->gid == tcred->sgid &&
> + cred->gid == tcred->gid))
> + goto ok;
> + if (ns_capable(tcred->user->user_ns, CAP_SYS_PTRACE))
> + goto ok;
> + rcu_read_unlock();
> + return -EPERM;
> +ok:
This is wrong. Please move that out into functions if you are unable to
get the conditions right.
Bastian
--
If a man had a child who'd gone anti-social, killed perhaps, he'd still
tend to protect that child.
-- McCoy, "The Ultimate Computer", stardate 4731.3
next prev parent reply other threads:[~2011-01-14 14:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-11 6:43 userns: targeted capabilities v4 Serge E. Hallyn
2011-01-11 6:43 ` [PATCH 01/08] Add a user_namespace as creator/owner of uts_namespace Serge E. Hallyn
2011-01-11 6:44 ` [PATCH 02/08] security: Make capabilities relative to the user namespace Serge E. Hallyn
2011-01-11 6:44 ` [PATCH 03/08] allow sethostname in a container Serge E. Hallyn
2011-01-11 16:14 ` Serge E. Hallyn
2011-02-04 15:56 ` Serge E. Hallyn
2011-01-11 6:44 ` [PATCH 04/08] allow killing tasks in your own or child userns Serge E. Hallyn
2011-01-11 6:44 ` [PATCH 05/08] Allow ptrace from non-init user namespaces Serge E. Hallyn
2011-01-14 14:46 ` Bastian Blank [this message]
2011-01-14 15:00 ` Bastian Blank
2011-01-15 0:35 ` Serge E. Hallyn
2011-01-11 6:44 ` [PATCH 06/08] user namespaces: convert all capable checks in kernel/sys.c Serge E. Hallyn
2011-01-11 6:45 ` [PATCH 07/08] user namespaces: convert several capable() calls Serge E. Hallyn
2011-01-11 6:45 ` [PATCH 08/08] userns: check user namespace for task->file uid equivalence checks Serge E. Hallyn
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