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From: Mimi Zohar <>
To: Jann Horn <>
	Stephen Smalley <>,
	Eric Biggers <>,
	linux-security-module <>,
	kernel list <>
Subject: Re: [RFC PATCH] ima: verify mprotect change is consistent with mmap policy
Date: Tue, 05 May 2020 10:16:44 -0400
Message-ID: <> (raw)
In-Reply-To: <>

Hi Jann,

On Tue, 2020-05-05 at 02:15 +0200, Jann Horn wrote:
> On Mon, May 4, 2020 at 11:18 PM Mimi Zohar <> wrote:
> > Files can be mmap'ed read/write and later changed to execute to circumvent
> > IMA's mmap appraise policy rules.  Due to locking issues (mmap semaphore
> > would be taken prior to i_mutex), files can not be measured or appraised at
> > this point.  Eliminate this integrity gap, by denying the mprotect
> > PROT_EXECUTE change, if an mmap appraise policy rule exists.
> Just keep in mind that there are other ways to create executable
> mappings containing controlled code; e.g. PROT_EXEC with
> MAP_ANONYMOUS, or writing to /proc/self/mem (which is a debugging API
> that works entirely without ever making the VMA writable - I had an
> old series to provide LSM hooks for that stuff at
> <>,
> but I guess I must have forgotten about it or something...).

Sure.  These sound like memory attacks, which should be closed, but
are probably out of scope for IMA.



      reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-04 21:17 Mimi Zohar
2020-05-04 22:51 ` Lakshmi Ramasubramanian
2020-05-05 15:33   ` Mimi Zohar
2020-05-05  0:15 ` Jann Horn
2020-05-05 14:16   ` Mimi Zohar [this message]

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