Re: [PATCH] x86-64, vsyscalls: Rename UNSAFE_VSYSCALLS toCOMPAT_VSYSCALLS
From: Ted Ts'o
Date: Mon Jun 06 2011 - 08:19:57 EST
On Mon, Jun 06, 2011 at 12:24:19PM +0200, Ingo Molnar wrote:
> -What: CONFIG_UNSAFE_VSYSCALLS (x86_64)
> +What: CONFIG_COMPAT_VSYSCALLS (x86_64)
> When: When glibc 2.14 or newer is ubitquitous. Perhaps mid-2012.
> -Why: Having user-executable code at a fixed address is a security problem.
> - Turning off CONFIG_UNSAFE_VSYSCALLS mostly removes the risk but will
> +Why: Having user-executable syscall invoking code at a fixed addresses makes
> + it easier for attackers to exploit security holes.
> + Turning off CONFIG_COMPAT_VSYSCALLS mostly removes the risk but will
> make the time() function slower on glibc versions 2.13 and below.
> Who: Andy Lutomirski <luto@xxxxxxx>
I'd suggest 2013 or 2014, at least. People using Ubuntu LTS and RHEL
6 are stuck back at glibc 2.11, and many of those users do like being
able to upgrade to newer kernels. And there are probably are a large
number of static binaries around.
Maybe in 2012 or so we change the to be 'no' (and I'd suggest adding a
comment in the feature-removal-schedule.txt file that this will also
break static binaries).
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