how to run dropbear on a system with a R/O /dev?

[Robert P. J. Day]

On Mon, 22 Dec 2008, Robert P. J. Day wrote:

>
>   i suspect i already know the answer to this, but is there any way to
> run dropbear on a system whose /dev directory is part of a larger
> romfs?
>
>   ssh to such a system worked fine during development when the root
> filesystem was NFS mounted and, therefore, writable.  but once that
> rootfs is flashed and is now mounted as a romfs, not surprisingly,
> dropbear can no longer accept incoming requests because (i'm
> guessing) while the appropriate /dev/ttyp[0-9] device files are there,
> dropbear has no ability to change their owner/perms, is that it?
> which generates the log error message:
>
>    pty_allocate: openpty: No child processes
>    no pty was allocated, couldn't execute
>
>   is there a way around this?  i would have guessed not, but i'm
> willing to be pleasantly surprised.

  actually, a thought just occurred to me.  i checked and, with an NFS
mount with a writable /dev, an ssh session comes in and is associated
with a /dev/ttyp[0-9] device file (the first available one).

  is another option to mount the /dev/pts filesystem and, if so, would
dropbear try to grab one of *those* device files instead?  since
that's a pseudo filesystem, its device files should be writable, no?
even when /dev itself isn't.

rday
--

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Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry:
    Have classroom, will lecture.

http://crashcourse.ca                          Waterloo, Ontario, CANADA
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