Re: ssh/sshd and /dev/tty

[Derek Young <derek at biddersedge dot com>]

I followed all your instructions and everything seems to be set up OK.

I was able to fix the problem where the server said "bad modes for /derek".
StrictModes was turned on in the /etc/ssh_config file.  I turned this off
temporarily.

I am still getting the "You have no controlling tty and no DISPLAY.  Cannot
read passphrase" error message.  I've traced this down to readpass.c.  It's
trying to open /dev/tty.

  if (from_stdin)
    f = stdin;
  else
    {
      /* Read the passphrase from /dev/tty to make it possible to ask it even
         when stdin has been redirected. */
      f = fopen("/dev/tty", "r");
      if (!f)
        {
          if (getenv("DISPLAY"))
            {
              // read via display
              // .... [ommitted] ...
            }

          /* No controlling terminal and no DISPLAY.  Nowhere to read. */
          fprintf(stderr, "You have no controlling tty and no DISPLAY.  Cannot
read passphrase.\n");
          exit(1);
        }
    }

The code is trying to open /dev/tty, which fails.  If I have DISPLAY set to
something, ssh tries running ssh-askpass to prompt for the password on an X
display.  This program complains about X11.dll (or something like that) not
being found (I'm not running X).

I read in a previous message you could do "mount con /dev/tty" to simulate a
tty, but this didn't work for me.

I'm guess that you might be running X and that's why this works for you?  Have
any ideas on a workaround for getting /dev/tty to work?  I suppose I could
apply the patches to ssh and recompile it, but if there's an easier work
around I'd rather not.

Thanks again for your help.

-- Derek Young

Patrick J. Fay wrote:

> Hello Derek,
> Do on the pc:
> mkdir /derek/.ssh
> ssh-keygen
> tell it to put the file in /derek/.ssh/identity
> give it a passphrase.
> ftp (or somehow get) your new identity* files to the other
> host in your otherhost:~derek/.ssh/identity*
> copy the ~/.ssh/identity.pub file to ~/.ssh/authorized_keys
> Note that each system that you want to ssh to will need a copy
> of your identity.pub in it's authorized_keys.
> That is how it 'knows' who to let in.
> Try that and let me know what happens. You should get further anyway.
> Pat
>
> On your pc (or on a host with ssh-keygen) you need to run ssh-keygen
> On Mon, 5 Jan 1998, Derek Young wrote:
>
> > Hello, I have just installed the ssh/sshd software made available from
> > http://gnu-win32.paranoia.ru/ , but I have not been able to get it to
> > work.  I changed my mounts to binary, set up the sshd config files, and
> > started sshd.  I have Sergey's coolview DLL installed.  I would like to
> > get this working so I can use it with CVS.
> >
> > When I run ssh, I get the message "You have no controlling tty and no
> > DISPLAY.  Cannot read passphrase."  Do I need some special environment
> > variables set to run this?  I've also tried starting with the -t
> > command, but this has the same effect.
> >
> >
> > I am running ssh from a regular command prompt (not bash or tcsh).  Even
> > if I run under bash I get the same error message.  I have run ssh-keygen
> > to create my key in my .ssh directory.
> >
> > I started sshd with the -d command to get debugging info.  After sshd
> > starts up with this...
> >
> > debug: sshd version 1.2.21 []
> > debug: Initializing random number generator; seed file
> > /etc/ssh_random_seed
> > log: Server listening on port 22.
> > log: Generating 768 bit RSA key.
> > Generating p:  ..........++ (distance 168)
> > Generating q:  ................++ (distance 184)
> > Computing the keys...
> > Testing the keys...
> > Key generation complete.
> > log: RSA key generation complete.
> >
> > ... and I run ssh I get this output from sshd...
> >
> > debug: Server will not fork when running in debugging mode.
> > log: Connection from 24.128.36.106 port 3539
> > debug: Client protocol version 1.5; client software version 1.2.21
> > debug: Sent 768 bit public key and 1024 bit host key.
> > debug: Encryption type: idea
> > debug: Received session key; encryption turned on.
> > debug: Attempting authentication for dyoung.
> > log: Rsa authentication refused for dyoung: bad modes for /derek
> > debug: RSA authentication for dyoung failed.
> > fatal: Connection closed by remote host.
> > debug: Calling cleanup 0x40e9e4(0x0)
> >
> >
> > I don't know what "bad modes for /derek" means (/derek is my home
> > directory).  Do I need some special permissions on this directory?  This
> > directory is listed in my /etc/passwd file as well.  sshd and ssh were
> > started as the same user, and I'm also trying to login with this user
> > name.
> >
> > Have I missed something?
> >
> > thanks for any help,
> >
> > -- Derek Young
> >
> >
> >
> >
>
> Patrick Fay, Ph.D., Intel Corp.            email:   pfay@co.intel.com
> Los Alamos National Lab                    wk:         (505) 665-9141
> CTI M.S. B296                              fax:        (505) 667-5921
> Los Alamos NM 87545    ASCI-RED http://www.acl.lanl.gov/~pfay/teraflop



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