[mosh-users] mosh-server fails to start on grsecurity kernel

[Trond Endrestøl]

On Tue, 7 Jun 2016 00:56-0400, Deven Lahoti wrote:

> Neither strace nor gdb will give me a backtrace, since they both lose track
> of it when it forks, but the failure happens after forking. For some
> reason, systemd says that coredumps are disabled for the process, so I
> can't get one of those either.

Have you tried strace -f?

> On Jun 7, 2016 00:31, "Alex Chernyakhovsky" <achernya at mit.edu> wrote:
> 
> > Unfortunately, that's not much to go on. Could you grab the core file
> > and get a backtrace? I'm assuming some syscall (probably malloc?)
> > failed.
> >
> > Sincerely,
> > -Alex
> >
> > On Tue, Jun 7, 2016 at 12:18 AM, Deven Lahoti <deywos at mit.edu> wrote:
> > > I don't think that's the problem, since it's now giving me:
> > > mosh-server[21489]: segfault at 0 ip           (null) sp 00007fffffffcbd8
> > > error 14 in mosh-server[555555554000+60000]
> > >
> > > On Mon, Jun 6, 2016 at 11:42 PM, Alex Chernyakhovsky <achernya at mit.edu>
> > > wrote:
> > >>
> > >> I think the offending line is
> > >>
> > >> Jun 06 22:32:19 <hostname> kernel: PAX: From 18.X.X.X: execution
> > >> attempt in: (null), 00000000-00000000 00000000
> > >> Jun 06 22:32:19 <hostname> kernel: PAX: terminating task:
> > >> /usr/bin/mosh-server(mosh-server):12505, uid/euid: XXXX/XXXX, PC:
> > >>       (nil), SP: 000003844385a508
> > >>
> > >> mosh-server needs to fork and exec to start subprocesses, and your
> > >> kernel/configuration doesn't consider mosh-server to be in the
> > >> whitelist.
> > >>
> > >> Sincerely,
> > >> -Alex
> > >>
> > >> On Mon, Jun 6, 2016 at 11:30 PM, Deven Lahoti <deywos at mit.edu> wrote:
> > >> > Hi, when trying to connect to my machine running Gentoo Hardened on
> > >> > kernel
> > >> > 4.4.8, mosh-server fails to start. Here are the logs (modified to
> > remove
> > >> > personal info) [http://web.mit.edu/deywos/www/mosh.log]. I'm not
> > really
> > >> > sure
> > >> > what the problem is, and I don't know much about how mosh works, so I
> > >> > was
> > >> > hoping someone here could help me out.
> > >> >
> > >> > Thanks,
> > >> > Deven

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