From: Ben Hutchings <ben@decadent.org.uk>
To: Jann Horn <jann@thejh.net>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Roland McGrath <roland@hack.frob.com>,
Oleg Nesterov <oleg@redhat.com>,
John Johansen <john.johansen@canonical.com>,
James Morris <james.l.morris@oracle.com>,
"Serge E. Hallyn" <serge@hallyn.com>,
Paul Moore <aul@paul-moore.com>,
Stephen Smalley <sds@tycho.nsa.gov>,
Eric Paris <eparis@parisplace.org>,
Casey Schaufler <casey@schaufler-ca.com>,
Kees Cook <eescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
Janis Danisevskis <jdanis@google.com>,
Seth Forshee <seth.forshee@canonical.com>,
"Eric . Biederman" <ebiederm@xmission.com>,
Thomas Gleixner <tglx@linutronix.de>,
Benjamin LaHaise <bcrl@kvack.org>
Cc: linux-fsdevel@vger.kernel.org,
linux-security-module@vger.kernel.org, security@kernel.org
Subject: Re: [PATCH 2/9] exec: turn self_exec_id into self_privunit_id
Date: Sun, 18 Sep 2016 19:13:27 +0100 [thread overview]
Message-ID: <1474222407.2428.2.camel@decadent.org.uk> (raw)
In-Reply-To: <1474211117-16674-3-git-send-email-jann@thejh.net>
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On Sun, 2016-09-18 at 17:05 +0200, Jann Horn wrote:
> This ensures that self_privunit_id ("privilege unit ID") is only shared by
> processes that share the mm_struct and the signal_struct; not just
> spatially, but also temporally. In other words, if you do execve() or
> clone() without CLONE_THREAD, you get a new privunit_id that has never been
> used before.
[...]
> +void increment_privunit_counter(void)
> +{
> + BUILD_BUG_ON(NR_CPUS > (1 << 16));
> + current->self_privunit_id = this_cpu_add_return(exec_counter, NR_CPUS);
> +}
[...]
This will wrap incorrectly if NR_CPUS is not a power of 2 (which is
unusual but allowed).
Ben.
--
Ben Hutchings
Klipstein's 4th Law of Prototyping and Production:
A fail-safe circuit will destroy
others.
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next prev parent reply other threads:[~2016-09-18 18:14 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-18 15:05 [PATCH 0/9] Various fixes related to ptrace_may_access() Jann Horn
2016-09-18 15:05 ` [PATCH 1/9] exec: introduce cred_guard_light Jann Horn
2016-09-18 15:05 ` [PATCH 2/9] exec: turn self_exec_id into self_privunit_id Jann Horn
2016-09-18 18:13 ` Ben Hutchings [this message]
2016-09-18 18:31 ` Jann Horn
2016-09-18 18:45 ` Ben Hutchings
2016-09-18 19:08 ` Jann Horn
2016-09-18 19:57 ` Andy Lutomirski
2016-09-19 15:31 ` Jann Horn
2016-09-18 15:05 ` [PATCH 3/9] proc: use open()-time creds for ptrace checks Jann Horn
2016-09-19 13:01 ` Stephen Smalley
2016-09-19 14:32 ` Jann Horn
2016-09-19 14:45 ` Stephen Smalley
2016-09-18 15:05 ` [PATCH 4/9] futex: don't leak robust_list pointer Jann Horn
2016-09-18 18:28 ` Ben Hutchings
2016-09-18 18:33 ` Jann Horn
2016-09-18 15:05 ` [PATCH 5/9] proc: lock properly in ptrace_may_access callers Jann Horn
2016-09-18 19:15 ` Jann Horn
2016-09-18 15:05 ` [PATCH 6/9] ptrace: warn on ptrace_may_access without proper locking Jann Horn
2016-09-18 15:05 ` [PATCH 7/9] ptrace: forbid ptrace checks against current_cred() from VFS context Jann Horn
2016-09-18 18:38 ` Ben Hutchings
2016-09-18 18:40 ` Jann Horn
2016-09-18 19:57 ` Andy Lutomirski
2016-09-18 20:38 ` Jann Horn
2016-09-18 20:18 ` Linus Torvalds
2016-09-18 20:52 ` Jann Horn
2016-09-18 15:05 ` [PATCH 8/9] fs/proc: fix attr access check Jann Horn
2016-09-18 15:05 ` [PATCH 9/9] Documentation: add security/ptrace_checks.txt Jann Horn
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