Messages in this thread | | | Date | Mon, 6 Jun 2011 14:37:38 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] x86-64, vsyscalls: Rename UNSAFE_VSYSCALLS to COMPAT_VSYSCALLS |
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* Ted Ts'o <tytso@mit.edu> wrote:
> 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@mit.edu> > > 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).
There is no breakage of binaries at all, just a small slowdown for time() calls - but even that is fixable via a simple, backportable few-liner glibc patch.
Thanks,
Ingo
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