linux-kernel - Re: [RFC PATCH v9 0/3] Add introspect_access(2) (was O

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Message-ID: <20200910170424.GU6583@casper.infradead.org>
Date:   Thu, 10 Sep 2020 18:04:24 +0100
From:   Matthew Wilcox <willy@...radead.org>
To:     Mickaël Salaün <mic@...ikod.net>
Cc:     linux-kernel@...r.kernel.org, Aleksa Sarai <cyphar@...har.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Al Viro <viro@...iv.linux.org.uk>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Andy Lutomirski <luto@...nel.org>,
        Arnd Bergmann <arnd@...db.de>,
        Casey Schaufler <casey@...aufler-ca.com>,
        Christian Brauner <christian.brauner@...ntu.com>,
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        Daniel Borkmann <daniel@...earbox.net>,
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Subject: Re: [RFC PATCH v9 0/3] Add introspect_access(2) (was O_MAYEXEC)

On Thu, Sep 10, 2020 at 06:46:09PM +0200, Mickaël Salaün wrote:
> This ninth patch series rework the previous AT_INTERPRETED and O_MAYEXEC
> series with a new syscall: introspect_access(2) .  Access check are now
> only possible on a file descriptor, which enable to avoid possible race
> conditions in user space.

But introspection is about examining _yourself_.  This isn't about
doing that.  It's about doing ... something ... to a script that you're
going to execute.  If the script were going to call the syscall, then
it might be introspection.  Or if the interpreter were measuring itself,
that would be introspection.  But neither of those would be useful things
to do, because an attacker could simply avoid doing them.

So, bad name.  What might be better?  sys_security_check()?
sys_measure()?  sys_verify_fd()?  I don't know.