[gentoo-user] DOSEMU 1.4.0.0 won't run as ordinary user anymore

[gentoo-user] DOSEMU 1.4.0.0 won't run as ordinary user anymore

[Walter Dnes]

  I've been using a specific program that only works under DOSEMU.  It
worked great.  Today, (after an update?) DOSEMU has stopped working as
an ordinary user, but still works for root.  Here's the screen capture

======================================================================
[d530][waltdnes][~] dosemu

LOWRAM mmap: Permission denied
Segmentation fault
======================================================================

  I haven't seen the LOWRAM error before.  I tried "/usr/bin/dosemu -s",
but it refused both my password and the root password.  I really don't
like the concept of running as root for ordinary stuff.  Is there a way
I can run it without full root privileges?  I haven't been able to
figure out the magic incantation in /etc/sudoers.

-- 
Walter Dnes <waltdnes@waltdnes.org>

[gentoo-user] [solved] DOSEMU 1.4.0.0 won't run as ordinary user anymore

[Walter Dnes]

On Sat, Aug 29, 2009 at 01:38:12AM -0400, Walter Dnes wrote
> I've been using a specific program that only works under DOSEMU.  It
> worked great.  Today, (after an update?) DOSEMU has stopped working as
> an ordinary user, but still works for root.  Here's the screen capture
> 
> ======================================================================
> [d530][waltdnes][~] dosemu
> 
> LOWRAM mmap: Permission denied
> Segmentation fault
> ======================================================================

  After spending some more time in Google, and trying various search
terms, I finally stumbled over the following...
https://bugs.launchpad.net/ubuntu/+source/dosemu/+bug/216398

Summary...

  * temporary workaround; as root, issue the command...
    sysctl vm.mmap_min_addr

  * the sysctl command has to be re-issued after every reboot.  Add
    vm.mmap_min_addr=0
    to /etc/sysctl.conf for it to be set properly every reboot

  That should be safe until the next sys-apps/baselayout update.

-- 
Walter Dnes <waltdnes@waltdnes.org>

Re: [gentoo-user] [solved] DOSEMU 1.4.0.0 won't run as ordinary user anymore

[Drew]

The changes to vm.mmap_min_addr were put in place to protect against a
number of null pointer deference attacks.


-- 
Drew

"Nothing in life is to be feared. It is only to be understood."
--Marie Curie

[gentoo-user] Re: [solved] DOSEMU 1.4.0.0 won't run as ordinary user anymore

[Nikos Chantziaras]

On 08/30/2009 06:47 AM, Walter Dnes wrote:
>    After spending some more time in Google, and trying various search
> terms, I finally stumbled over the following...
> https://bugs.launchpad.net/ubuntu/+source/dosemu/+bug/216398
>
> Summary...
>
>    * temporary workaround; as root, issue the command...
>      sysctl vm.mmap_min_addr
>
>    * the sysctl command has to be re-issued after every reboot.  Add
>      vm.mmap_min_addr=0
>      to /etc/sysctl.conf for it to be set properly every reboot
>
>    That should be safe until the next sys-apps/baselayout update.

This has to be fixed in dosemu, not baselayout :P