Re: sshd -- cannot relabel with system_u:object_r:sshd_devpts_t
On Tue, 13 Apr 2004 11:03, Tom Mitchell <mitch48(a)sbcglobal.net> wrote:
I just killed a remote terminal window and noted this message triple
in the
log/messages:
sshd(pam_unix)[30912]: session opened for user root by (uid=0)
sshd[30912]: Warning! Could not relabel with
system_u:object_r:sshd_devpts_t, not relabeling.
What version of pam do you have installed? It should not even be trying to
relabel a pty back to it's original type. The idea is that if someone
exploits a copy of sshd we want to make it as difficult as possible to trick
it into granting access to another user's session. Allowing sshd to label
terminals back from userpty_type makes things easier for an attacker.
If this is what I think it is sshd will slowly run out of available
ptys.
I've noticed that 2.6 kernels don't seem to reuse pty numbers until they reach
some large number. I don't think that there's any problem of running out of
available ptys, it seems to handle things the same way in permissive and
enforcing modes.
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