From: valdis.kletnieks@vt.edu
To: Lev Olshvang <levonshe@yandex.com>
Cc: linux-il <linux-il@cs.huji.ac.il>,
kernelnewbies <kernelnewbies@kernelnewbies.org>
Subject: Re: Security-What can be done in kernel to disable forever executable memory modificaton
Date: Sat, 12 Jan 2019 14:54:09 -0500 [thread overview]
Message-ID: <11945.1547322849@turing-police.cc.vt.edu> (raw)
In-Reply-To: <589971547299140@myt5-f9d71769b752.qloud-c.yandex.net>
On Sat, 12 Jan 2019 16:19:00 +0300, Lev Olshvang said:
> The fact that the text segment could be modified is bad news from the
> security standpoint.
We've known that for at least a decade now. Maybe longer. And we
already had this discussion once, about a week ago.
> I am not sure whether it is actually happening, perhaps instead new pages are
> allocated, sort of COW (copy on write).
In which case, you should probably stop and verify if it's happening.
> And here I am getting to the point :
> Is there any way to disable the change of permission bits of PTE? Is it
> possible in the hardware (ARM) or should kernel be patched?
Are you sure you want to disable *all* changes of a PTE?
Hint: Figure out how shared libraries are loaded before you go any further.
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prev parent reply other threads:[~2019-01-12 19:53 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-12 13:19 Security-What can be done in kernel to disable forever executable memory modificaton Lev Olshvang
2019-01-12 19:54 ` valdis.kletnieks [this message]
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