linux-kernel - Re: [PATCH v4 1/6] cgroup: unify attach permission checking

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 20 Jan 2020 15:42:45 +0100
From:   Oleg Nesterov <oleg@...hat.com>
To:     Christian Brauner <christian.brauner@...ntu.com>
Cc:     linux-api@...r.kernel.org, linux-kernel@...r.kernel.org,
        Tejun Heo <tj@...nel.org>, Li Zefan <lizefan@...wei.com>,
        Johannes Weiner <hannes@...xchg.org>, cgroups@...r.kernel.org
Subject: Re: [PATCH v4 1/6] cgroup: unify attach permission checking

I guess I am totally confused, but...

On 01/17, Christian Brauner wrote:
>
> +static inline bool cgroup_same_domain(const struct cgroup *src_cgrp,
> +				      const struct cgroup *dst_cgrp)
> +{
> +	return src_cgrp->dom_cgrp == dst_cgrp->dom_cgrp;
> +}
> +
> +static int cgroup_attach_permissions(struct cgroup *src_cgrp,
> +				     struct cgroup *dst_cgrp,
> +				     struct super_block *sb, bool thread)
> +{
> +	int ret = 0;
> +
> +	ret = cgroup_procs_write_permission(src_cgrp, dst_cgrp, sb);
> +	if (ret)
> +		return ret;
> +
> +	ret = cgroup_migrate_vet_dst(dst_cgrp);
> +	if (ret)
> +		return ret;
> +
> +	if (thread &&
> +	    !cgroup_same_domain(src_cgrp->dom_cgrp, dst_cgrp->dom_cgrp))
                                        ^^^^^^^^^^          ^^^^^^^^^^

             cgroup_same_domain(src_cgrp, dst_cgrp)

no?

And given that cgroup_same_domain() has no other users, perhaps it can
simply check

	     src_cgrp->dom_cgrp != dst_cgrp->dom_cgrp

?

Oleg.