linux-kernel - Re: [PATCH] ima: cleanup the match

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Message-ID: <20181218040629.GT2217@ZenIV.linux.org.uk>
Date:   Tue, 18 Dec 2018 04:06:29 +0000
From:   Al Viro <viro@...iv.linux.org.uk>
To:     Mimi Zohar <zohar@...ux.ibm.com>
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        linux-integrity@...r.kernel.org,
        James Morris James Morris <jmorris@...ei.org>,
        Linux List Kernel Mailing <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ima: cleanup the match_token policy code

On Mon, Dec 17, 2018 at 10:00:07PM -0500, Mimi Zohar wrote:

> Could you expand on commit 5b2ea6199614 ("selinux: switch away from
> match_token()") patch description.  All that it says is "It's not a
> good fit, unfortunately, and the next step will make it even less so.
> Open-code what we need here."  And there's even less for the
> equivalent Smack patch, which just says "same issue as with
> selinux...".

match_token() would require messing around with strsep() or something
equivalent.  It's not a regex; foo=%s has no idea that comma is in any
way special, etc.

As for the next commit...  Killing the Cthulhu-awful mess in
selinux_sb_eat_lsm_opts() (allocating two temproraries, concatenating
(comma-separated) non-LSM options into one, concatenating (pipe-separated)
dequoted LSM options into another, then splitting that another by '|'
instances and figuring out which option each piece is, etc.)
is a Good Thing(tm).  And having to dance around the needs of
match_token() adds extra headache, for no good reason.