From: Solar Designer <solar@openwall.com>
To: kernel-hardening@lists.openwall.com
Cc: Kees Cook <keescook@chromium.org>,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: [kernel-hardening] Re: [PATCH 3/3] security: Yama: add ptrace relationship tracking interface
Date: Sat, 19 Nov 2011 20:59:03 +0400 [thread overview]
Message-ID: <20111119165903.GB2208@openwall.com> (raw)
In-Reply-To: <20111119163058.GA3131@albatros>
On Sat, Nov 19, 2011 at 08:30:58PM +0400, Vasiliy Kulikov wrote:
> On Wed, Oct 26, 2011 at 16:49 -0700, Kees Cook wrote:
> > + if (mode == PTRACE_MODE_ATTACH &&
> > + ptrace_scope &&
> > + !capable(CAP_SYS_PTRACE) &&
> > + !task_is_descendant(current, child) &&
> > + !ptracer_exception_found(current, child))
> > + rc = -EPERM;
>
> capable() is better to put after all other tests
Right, but...
> as a failed capable()
> might emit a false positive warning into logs or something.
...primarily for another reason: a successful capable() sets
PF_SUPERPRIV, whereas the permission might have been granted without
capable() as well. The PF_SUPERPRIV flag is visible via BSD process
accounting.
Alexander
WARNING: multiple messages have this Message-ID (diff)
From: Solar Designer <solar@openwall.com>
To: kernel-hardening@lists.openwall.com
Cc: Kees Cook <keescook@chromium.org>,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org
Subject: Re: [PATCH 3/3] security: Yama: add ptrace relationship tracking interface
Date: Sat, 19 Nov 2011 20:59:03 +0400 [thread overview]
Message-ID: <20111119165903.GB2208@openwall.com> (raw)
In-Reply-To: <20111119163058.GA3131@albatros>
On Sat, Nov 19, 2011 at 08:30:58PM +0400, Vasiliy Kulikov wrote:
> On Wed, Oct 26, 2011 at 16:49 -0700, Kees Cook wrote:
> > + if (mode == PTRACE_MODE_ATTACH &&
> > + ptrace_scope &&
> > + !capable(CAP_SYS_PTRACE) &&
> > + !task_is_descendant(current, child) &&
> > + !ptracer_exception_found(current, child))
> > + rc = -EPERM;
>
> capable() is better to put after all other tests
Right, but...
> as a failed capable()
> might emit a false positive warning into logs or something.
...primarily for another reason: a successful capable() sets
PF_SUPERPRIV, whereas the permission might have been granted without
capable() as well. The PF_SUPERPRIV flag is visible via BSD process
accounting.
Alexander
next prev parent reply other threads:[~2011-11-19 16:59 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-26 23:49 [PATCH v6 0/3] security: Yama LSM Kees Cook
2011-10-26 23:49 ` [PATCH 1/3] " Kees Cook
2011-10-26 23:49 ` [PATCH 2/3] security: create task_free security callback Kees Cook
2011-10-26 23:49 ` [PATCH 3/3] security: Yama: add ptrace relationship tracking interface Kees Cook
2011-11-19 16:30 ` [kernel-hardening] " Vasiliy Kulikov
2011-11-19 16:30 ` Vasiliy Kulikov
2011-11-19 16:59 ` Solar Designer [this message]
2011-11-19 16:59 ` Solar Designer
2011-11-21 18:40 ` [kernel-hardening] " Kees Cook
2011-11-21 18:40 ` Kees Cook
2011-11-01 20:45 ` [PATCH v6 0/3] security: Yama LSM James Morris
2011-11-01 21:05 ` Kees Cook
2011-11-01 21:37 ` James Morris
2011-11-01 23:23 ` Kees Cook
2011-11-18 4:17 ` James Morris
2011-11-18 21:39 ` Kees Cook
2011-11-18 21:45 ` Roland McGrath
2011-11-18 22:44 ` Kees Cook
2011-11-18 23:18 ` Kees Cook
2011-11-21 19:18 ` [kernel-hardening] [RFC] Make Yama pid_ns aware Vasiliy Kulikov
2011-11-21 19:18 ` Vasiliy Kulikov
2011-11-21 19:42 ` [kernel-hardening] " Kees Cook
2011-11-21 19:42 ` Kees Cook
2011-11-22 18:13 ` [kernel-hardening] " Serge Hallyn
2011-11-22 18:13 ` Serge Hallyn
2011-11-22 19:20 ` [kernel-hardening] " Vasiliy Kulikov
2011-11-22 19:20 ` Vasiliy Kulikov
2011-11-22 20:10 ` [kernel-hardening] " Serge Hallyn
2011-11-22 20:10 ` Serge Hallyn
2011-11-23 7:45 ` [kernel-hardening] " Vasiliy Kulikov
2011-11-23 7:45 ` Vasiliy Kulikov
2011-11-23 14:41 ` [kernel-hardening] " Serge Hallyn
2011-11-23 14:41 ` Serge Hallyn
2011-11-23 14:49 ` [kernel-hardening] " Serge E. Hallyn
2011-11-23 14:49 ` Serge E. Hallyn
2011-11-23 16:55 ` [kernel-hardening] " Vasiliy Kulikov
2011-11-23 16:55 ` Vasiliy Kulikov
2011-11-23 17:00 ` [kernel-hardening] " Serge Hallyn
2011-11-23 17:00 ` Serge Hallyn
2011-11-28 18:12 ` [kernel-hardening] " Kees Cook
2011-11-28 18:12 ` Kees Cook
2011-11-28 18:14 ` [kernel-hardening] " Vasiliy Kulikov
2011-11-28 18:14 ` Vasiliy Kulikov
2011-11-28 19:16 ` [kernel-hardening] [RFC -resend] " Vasiliy Kulikov
2011-11-28 19:16 ` Vasiliy Kulikov
2011-11-28 19:35 ` [kernel-hardening] " Kees Cook
2011-11-28 19:35 ` Kees Cook
2011-11-28 20:15 ` [kernel-hardening] " Kees Cook
2011-11-28 20:15 ` Kees Cook
2011-11-28 20:00 ` [kernel-hardening] " Serge E. Hallyn
2011-11-28 20:00 ` Serge E. Hallyn
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