From: Mimi Zohar <zohar@linux.ibm.com>
To: Roberto Sassu <roberto.sassu@huaweicloud.com>,
dmitry.kasatkin@gmail.com, eric.snowberg@oracle.com,
paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com,
john.johansen@canonical.com, stephen.smalley.work@gmail.com,
casey@schaufler-ca.com, eparis@redhat.com
Cc: linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, guozihua@huawei.com,
omosnace@redhat.com, audit@vger.kernel.org,
apparmor@lists.ubuntu.com, selinux@vger.kernel.org,
Roberto Sassu <roberto.sassu@huawei.com>
Subject: Re: [RFC][PATCH] ima: Use sequence number to wait for policy updates
Date: Tue, 07 May 2024 16:27:33 -0400 [thread overview]
Message-ID: <cc11e15bdbfbb36415b36a796387e130b764fd6a.camel@linux.ibm.com> (raw)
In-Reply-To: <e6e2b31983610bf566d8046edbac0e00c8453233.camel@huaweicloud.com>
Hi Roberto,
On Tue, 2024-05-07 at 11:32 +0200, Roberto Sassu wrote:
> On Tue, 2024-05-07 at 11:28 +0200, Roberto Sassu wrote:
> > From: Roberto Sassu <roberto.sassu@huawei.com>
> >
> > Maintain a global sequence number, and set it to individual policy rules,
> > when they are created.
>
> Just did an attempt, to see if this path is viable.
>
> This patch would be an alternative to:
>
> [PATCH v3] ima: Avoid blocking in RCU read-side critical section
Stephen had said,
"Sidebar: the refactoring of the SELinux policy loading logic may have
made it possible to revisit the approaches here to permit holding a
reference to the policy from which the rule was derived so that we
don't have to return -ESTALE in this scenario."
Removing -ESTALE would be the best solution. We could then remove the -ESTALE
detection.
I assume the change would be in selinux_policy_commit(). Instead of freeing the
old policy, define and increment a per policy reference count for each
registered notifier callback.
/* Free the old policy */
synchronize_rcu();
selinux_policy_free(oldpolicy);
kfree(load_state->convert_data);
/* Notify others of the policy change */
selinux_notify_policy_change(seqno);
Mimi
prev parent reply other threads:[~2024-05-07 20:28 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-07 9:28 [RFC][PATCH] ima: Use sequence number to wait for policy updates Roberto Sassu
2024-05-07 9:32 ` Roberto Sassu
2024-05-07 20:27 ` Mimi Zohar [this message]
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