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Date:   Wed, 12 Dec 2018 19:02:28 -0800
From:   Matthew Wilcox <willy@infradead.org>
To:     =?iso-8859-1?Q?Micka=EBl_Sala=FCn?= <mic@digikod.net>
Cc:     linux-kernel@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>,
        James Morris <jmorris@namei.org>,
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        =?iso-8859-1?Q?Micka=EBl_Sala=FCn?= <mickael.salaun@ssi.gouv.fr>,
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        <philippe.trebuchet@ssi.gouv.fr>, Shuah Khan <shuah@kernel.org>,
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        Vincent Strubel <vincent.strubel@ssi.gouv.fr>,
        Yves-Alexis Perez <yves-alexis.perez@ssi.gouv.fr>,
        kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org,
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        linux-fsdevel@vger.kernel.org
Subject: Re: [RFC PATCH v1 0/5] Add support for O_MAYEXEC
Message-ID: <20181213030228.GM6830@bombadil.infradead.org>
References: <20181212081712.32347-1-mic@digikod.net>
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On Wed, Dec 12, 2018 at 09:17:07AM +0100, Micka?l Sala?n wrote:
> The goal of this patch series is to control script interpretation.  A
> new O_MAYEXEC flag used by sys_open() is added to enable userland script
> interpreter to delegate to the kernel (and thus the system security
> policy) the permission to interpret scripts or other files containing
> what can be seen as commands.

I don't have a problem with the concept, but we're running low on O_ bits.
Does this have to be done before the process gets a file descriptor,
or could we have a new syscall?  Since we're going to be changing the
interpreters anyway, it doesn't seem like too much of an imposition to
ask them to use:

	int verify_for_exec(int fd)

instead of adding an O_MAYEXEC.