lkml.org 
[lkml]   [2006]   [May]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] Gerd Hoffman's move-vsyscall-into-user-address-range patch
Zachary Amsden <zach@vmware.com> wrote:
>
> Jakub Jelinek wrote:
> >
> > That's known bug in early glibcs short after adding vDSO support.
> > The vDSO support has been added in May 2003 to CVS glibc (i.e. post glibc
> > 2.3.2) and the problems have been fixed when they were discovered, in
> > February 2004:
> > http://sources.redhat.com/ml/libc-hacker/2004-02/msg00053.html
> > http://sources.redhat.com/ml/libc-hacker/2004-02/msg00059.html
> >
> > I strongly believe we want randomized vDSOs, people are already abusing the
> > fix mapped vDSO for attacks, and I think the unfortunate 10 months of broken
> > glibc shouldn't stop that forever. Anyone using such glibc can still use
> > vdso=0, or do that just once and upgrade to somewhat more recent glibc.
> >
>
> While I'm now inclined to agree with randomization, I think the default
> should be off. You can quite easily "echo 1 >
> /proc/sys/kernel/vdso_randomization" in the RC scripts, which allows you
> to maintain compatibility for everyone and get randomization turned on
> early enough to thwart attacks against any vulnerable daemons.
>

It kinda sucks but yes, that's obviously least-breakage approach. It does
mean that many people won't benefit from (and won't test!) the new feature
though.

Unless there's some sneaky way of auto-detecting a modern userspace,
perhaps (something which mounts /sys?).

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

\
 
 \ /
  Last update: 2006-05-22 19:18    [W:0.610 / U:0.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site