On Tue, 2009-01-27 at 17:44 +1100, Declan Mullen wrote: > > John A. Sullivan III wrote: > > On Mon, 2009-01-26 at 07:26 -0500, John A. Sullivan III wrote: > > > >> On Mon, 2009-01-26 at 06:28 -0500, John A. Sullivan III wrote: > >> > >>> On Mon, 2009-01-26 at 20:25 +1100, Declan Mullen wrote: > >>> > >>>> Hi > >>>> > >>>> When I ssh into my Linux server, the login succeeds but I notice that I > >>>> get the following type of entry appended to the auth.log : > >>>> > >>>> Jan 26 17:10:45 maxv1 sshd[32624]: error writing /proc/self/oom_adj: > >>>> Permission denied > >>>> > >>>> What are the implications of the sshd not being able to write to the > >>>> oom_adj ? Ie Is this error significant or should I just ignore it ? > >>>> > >>>> The sshd's write is failing because the server I'm logging into is a > >>>> VServer guest/virtual server, and the VServer virtualisation technology > >>>> places restrictions on what can be written to the /proc filesystem from > >>>> within the guest. > >>>> > >>>> The guest server OS is Debian Lenny and the sshd versions is > >>>> "1:5.1p1-5". Within the sshd_config Privilege Separation is turned on. > >>>> > >>>> The host server's kernel is Lenny's "linux-source-2.6.26" (version > >>>> "2.6.26-13") with Lenny's vserver patches applied from > >>>> "linux-patch-debian-2.6.26" (version "2.6.26-13"). The host's > >>>> util-vserver package is version "0.30.216~r2772-6". The host's > >>>> "vserver-debiantools" package is version "0.6.3". > >>>> > >>> <snip> > >>> I'm facing the same issue and would like for the guest to be able to set > >>> oom_adj. I would imagine this is done by editing the vprocunhidefiles > >>> file However, before doing so, I'd like to ask the list if there is a > >>> security issue in doing so. I suppose a savvy guest could make their > >>> system a hog - the last one to have any processes shut down in an out of > >>> memory condition thus creating an availability problem but I wouldn't > >>> imagine it creates a data confidentiality or integrity problem. Is this > >>> true? Thanks - John > >>> > >> Oops! That's not true. OpenSSH appears to want to create this /proc > >> entry. vprocunhide doesn't seem to solve that problem! - John > >> > > > > By the way, if one wants to stop the error message, one can > > edit /etc/init.d/ssh and comment out the calls to adjust_oom in the > > start and restart sections of the init script - John > > > > I have just noticed that in /etc/default/ssh : > > # OOM-killer adjustment for sshd (see > # linux/Documentation/filesystems/proc.txt; lower values reduce likelihood > # of being killed, while -17 means the OOM-killer will ignore sshd; set to > # the empty string to skip adjustment) > SSHD_OOM_ADJUST=-17 > > I've modified this file to set SSHD_OOM_ADJUST to a null string, and now > sshd no longer attempts to write to oom_adj and the error messages no > longer occur. <snip> Much better solution. I had read in an older post that doing so did not work as expected. I'm glad it has been fixed and will change my installations to this method. Thanks - John -- John A. Sullivan III Open Source Development Corporation +1 207-985-7880 jsullivan@opensourcedevel.com http://www.spiritualoutreach.com Making Christianity intelligible to secular society