On Wed, Nov 04, 2009 at 04:55:58PM +0100, Justin Smith wrote: > On Wed, Nov 4, 2009 at 4:14 PM, Todd T. Fries <[email protected]> wrote: > > Penned by Justin Smith on 20091104 15:45.33, we have: > > | Theo wrote: > > | > > | > For the record, this particular problem was resolved in OpenBSD a > > | while back, in 2008. > > | > > | Nice, but: > > | > > | "Since 2.6.23, it has been possible to prevent applications from > > | mapping low pages (to prevent null pointer dereferencing in the > > | kernel) via the /proc/sys/vm/mmap_min_addr sysctl, which sets the > > | minimum address allowed for such mappings." > > | > > | 2.6.23 released: Tue, 9 Oct 2007 > > | > > | Ref: > > | http://lkml.org/lkml/2007/10/9/241 > > | http://james-morris.livejournal.com/26303.html > > | > > | -- > > | JS > > > > And now we get into the fun stuff. > > > > Ever heard of 'secure by default' ? > > > > This knob is set to '0' by default. > > > > How many Linux installations actually read the above paragraph, understood > > what value it could have to set to something other than zero, and changed > > it accordingly. > > > > 'Nuff said. > > > "By default, Ubuntu 8.04 and later with a non-zero > /proc/sys/vm/mmap_min_addr setting were not vulnerable." > > Ubuntu 8.04 released in 2008 april.
quote from the article in the subject: The latest bug is mitigated by default on most Linux distributions, thanks to their correct implementation of the mmap_min_addr feature. But to make RHEL compatible with a larger body of applications, that distribution is vulnerable to attack even when the OS shows the feature is enabled, Spengler said. so, on RedHat, one can't even turn it on? doesn't Linus work for RedHat? -- [email protected] SDF Public Access UNIX System - http://sdf.lonestar.org
