linux-kernel - Re: [PATCH v3 2/2] proc: ensure security hook is called after exec

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]

Message-ID: <CAEjxPJ4bUxSp3hMV9k5Z5Zpev=ravd6EJheC1Rdg+_72eUiNLA@mail.gmail.com>
Date:   Mon, 4 Jan 2021 09:16:34 -0500
From:   Stephen Smalley <stephen.smalley.work@...il.com>
To:     Stephen Brennan <stephen.s.brennan@...cle.com>
Cc:     Alexey Dobriyan <adobriyan@...il.com>,
        James Morris <jmorris@...ei.org>,
        "Serge E. Hallyn" <serge@...lyn.com>,
        LSM List <linux-security-module@...r.kernel.org>,
        Paul Moore <paul@...l-moore.com>,
        Eric Paris <eparis@...isplace.org>,
        SElinux list <selinux@...r.kernel.org>,
        Casey Schaufler <casey@...aufler-ca.com>,
        Eric Biederman <ebiederm@...ssion.com>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Linux FS Devel <linux-fsdevel@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Matthew Wilcox <willy@...radead.org>
Subject: Re: [PATCH v3 2/2] proc: ensure security hook is called after exec

On Fri, Dec 18, 2020 at 7:06 PM Stephen Brennan
<stephen.s.brennan@...cle.com> wrote:
>
> Smack needs its security_task_to_inode() hook to be called when a task
> execs a new executable. Store the self_exec_id of the task and call the
> hook via pid_update_inode() whenever the exec_id changes.
>
> Signed-off-by: Stephen Brennan <stephen.s.brennan@...cle.com>

Sorry to be late in responding, but the proc inode security structure
needs to be updated not only upon a context-changing exec but also
upon a setcon(3) aka write to /proc/self/attr/current just like the
uid/gid needs to be updated not only upon a setuid exec but also upon
a setuid(2).  I'm also unclear as to why you can't call
security_task_to_inode during RCU lookup; it doesn't block/sleep
AFAICT.
All it does is take a spinlock and update a few fields.