From: Andrew Morton <akpm@linux-foundation.org>
To: "Serge E. Hallyn" <serge@hallyn.com>
Cc: LSM <linux-security-module@vger.kernel.org>,
James Morris <jmorris@namei.org>,
Kees Cook <kees.cook@canonical.com>,
containers@lists.linux-foundation.org,
kernel list <linux-kernel@vger.kernel.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Alexey Dobriyan <adobriyan@gmail.com>,
Michael Kerrisk <mtk.manpages@gmail.com>,
xemul@parallels.com, dhowells@redhat.com
Subject: Re: [PATCH 4/9] allow killing tasks in your own or child userns
Date: Fri, 18 Feb 2011 15:59:21 -0800 [thread overview]
Message-ID: <20110218155921.440f1137.akpm@linux-foundation.org> (raw)
In-Reply-To: <20110217150325.GD26395@mail.hallyn.com>
On Thu, 17 Feb 2011 15:03:25 +0000
"Serge E. Hallyn" <serge@hallyn.com> wrote:
> /*
> + * called with RCU read lock from check_kill_permission()
> + */
> +static inline int kill_ok_by_cred(struct task_struct *t)
> +{
> + const struct cred *cred = current_cred();
> + const struct cred *tcred = __task_cred(t);
> +
> + if (cred->user->user_ns == tcred->user->user_ns &&
> + (cred->euid == tcred->suid ||
> + cred->euid == tcred->uid ||
> + cred->uid == tcred->suid ||
> + cred->uid == tcred->uid))
> + return 1;
> +
> + if (ns_capable(tcred->user->user_ns, CAP_KILL))
> + return 1;
> +
> + return 0;
> +}
The compiler will inline this for us.
> +/*
> * Bad permissions for sending the signal
> * - the caller must hold the RCU read lock
> */
> static int check_kill_permission(int sig, struct siginfo *info,
> struct task_struct *t)
> {
> - const struct cred *cred, *tcred;
> struct pid *sid;
> int error;
>
> @@ -656,14 +676,8 @@ static int check_kill_permission(int sig, struct siginfo *info,
> if (error)
> return error;
>
> - cred = current_cred();
> - tcred = __task_cred(t);
> if (!same_thread_group(current, t) &&
> - (cred->euid ^ tcred->suid) &&
> - (cred->euid ^ tcred->uid) &&
> - (cred->uid ^ tcred->suid) &&
> - (cred->uid ^ tcred->uid) &&
> - !capable(CAP_KILL)) {
> + !kill_ok_by_cred(t)) {
> switch (sig) {
> case SIGCONT:
> sid = task_session(t);
next prev parent reply other threads:[~2011-02-19 0:00 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-17 15:02 userns: targeted capabilities v5 Serge E. Hallyn
2011-02-17 15:02 ` [PATCH 1/9] Add a user_namespace as creator/owner of uts_namespace Serge E. Hallyn
2011-02-18 3:31 ` Eric W. Biederman
2011-02-18 16:57 ` Daniel Lezcano
2011-02-18 23:59 ` Andrew Morton
2011-02-17 15:03 ` [PATCH 2/9] security: Make capabilities relative to the user namespace Serge E. Hallyn
2011-02-18 3:46 ` Eric W. Biederman
2011-02-18 23:44 ` Daniel Lezcano
2011-02-18 23:59 ` Andrew Morton
2011-02-17 15:03 ` [PATCH 3/9] allow sethostname in a container Serge E. Hallyn
2011-02-18 3:05 ` Eric W. Biederman
2011-02-18 23:46 ` Daniel Lezcano
2011-02-17 15:03 ` [PATCH 4/9] allow killing tasks in your own or child userns Serge E. Hallyn
2011-02-18 3:00 ` Eric W. Biederman
2011-02-18 23:59 ` Andrew Morton [this message]
2011-02-24 0:48 ` Serge E. Hallyn
2011-02-24 0:54 ` Andrew Morton
2011-02-19 10:55 ` Daniel Lezcano
2011-02-17 15:03 ` [PATCH 5/9] Allow ptrace from non-init user namespaces Serge E. Hallyn
2011-02-18 2:59 ` Eric W. Biederman
2011-02-18 4:36 ` Serge E. Hallyn
2011-02-24 0:49 ` [PATCH] userns: ptrace: incorporate feedback from Eric Serge E. Hallyn
2011-02-24 0:56 ` Andrew Morton
2011-02-24 3:15 ` Serge E. Hallyn
2011-02-18 23:59 ` [PATCH 5/9] Allow ptrace from non-init user namespaces Andrew Morton
2011-02-24 0:43 ` Serge E. Hallyn
2011-02-19 17:49 ` Daniel Lezcano
2011-02-17 15:03 ` [PATCH 6/9] user namespaces: convert all capable checks in kernel/sys.c Serge E. Hallyn
2011-02-18 1:57 ` Eric W. Biederman
2011-02-18 23:59 ` Andrew Morton
2011-02-19 0:01 ` Andrew Morton
2011-02-19 17:52 ` Daniel Lezcano
2011-02-17 15:03 ` [PATCH 7/9] add a user namespace owner of ipc ns Serge E. Hallyn
2011-02-18 3:19 ` Eric W. Biederman
2011-02-18 23:59 ` Andrew Morton
2011-02-19 17:57 ` Daniel Lezcano
2011-02-17 15:03 ` [PATCH 8/9] user namespaces: convert several capable() calls Serge E. Hallyn
2011-02-18 1:51 ` Eric W. Biederman
2011-02-19 19:07 ` Daniel Lezcano
2011-02-17 15:04 ` [PATCH 9/9] userns: check user namespace for task->file uid equivalence checks Serge E. Hallyn
2011-02-18 1:29 ` Eric W. Biederman
2011-02-18 23:59 ` Andrew Morton
2011-02-24 3:24 ` Serge E. Hallyn
2011-02-24 5:08 ` Andrew Morton
2011-02-19 19:22 ` Daniel Lezcano
2011-02-18 0:21 ` userns: targeted capabilities v5 Andrew Morton
2011-02-18 3:53 ` Eric W. Biederman
2011-02-18 4:28 ` Serge E. Hallyn
2011-02-23 11:40 ` [PATCH 2/9] security: Make capabilities relative to the user namespace David Howells
2011-02-23 12:01 ` David Howells
2011-02-23 13:43 ` Serge E. Hallyn
2011-02-23 12:05 ` User namespaces and keys David Howells
2011-02-23 13:58 ` Serge E. Hallyn
2011-02-23 14:46 ` Eric W. Biederman
2011-02-23 15:06 ` David Howells
2011-02-23 15:45 ` Eric W. Biederman
2011-02-23 15:53 ` Serge E. Hallyn
2011-02-23 19:24 ` Casey Schaufler
2011-02-23 20:55 ` Eric W. Biederman
2011-02-23 21:37 ` Casey Schaufler
2011-02-24 6:56 ` Eric W. Biederman
2011-02-23 16:59 ` [PATCH 2/9] security: Make capabilities relative to the user namespace David Howells
2011-02-23 17:05 ` [PATCH 5/9] Allow ptrace from non-init user namespaces David Howells
2011-02-23 17:11 ` David Howells
2011-02-23 17:16 ` [PATCH 1/9] Add a user_namespace as creator/owner of uts_namespace David Howells
2011-02-23 21:21 ` Eric W. Biederman
2011-02-23 23:19 ` David Howells
2011-02-23 23:54 ` Eric W. Biederman
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