linux-kernel - Re: revert PIE randomization?

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 07 Jan 2007 06:42:12 +0800
From:	David Woodhouse <dwmw2@...radead.org>
To:	Hugh Dickins <hugh@...itas.com>
Cc:	Andrew Morton <akpm@...l.org>, Linus Torvalds <torvalds@...l.org>,
	Marcus Meissner <meissner@...e.de>, Andi Kleen <ak@...e.de>,
	Ingo Molnar <mingo@...e.hu>,
	Dave Jones <davej@...emonkey.org.uk>,
	Arjan van de Ven <arjan@...ux.intel.com>,
	linux-kernel@...r.kernel.org
Subject: Re: revert PIE randomization?

On Sat, 2007-01-06 at 20:11 +0000, Hugh Dickins wrote:
> And I notice that Andi added a personality & ADDR_NO_RANDOMIZE check
> into randomize_stack_top: I cannot see why that's necessary there,
> but if it is, then should the ET_DYN case add it too?)

While I think of it... it seems that ADDR_NO_RANDOMIZE isn't "inherited"
across exec of 32-bit binaries on x86_64 or ppc64. The personality flags
get wiped out when we detect a 32-bit ELF executable and set the
personality to PER_LINUX32.

This causes suboptimal behaviour from userspace code which checks
whether it can set ADDR_NO_RANDOMIZE with a sys_personality() call, and
if so re-execs itself. Run on x86_64 or ppc64, these go into an endless
loop because it always gets cleared in the exec.

I've seen such code in two places recently (Macaulay2 and sbcl, iirc).

-- 
dwmw2

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/