Re: ssh/sshd and /dev/tty

["Patrick J. Fay" <pfay at acl dot lanl dot gov>]

Hello Derek,
No I'm not using x stuff.
Let's try this all on your PC.
Try:
1st window
./sshd -d
2nd window
env|grep HOST
(for bash)
export CYGWIN_TITLE=1 
export CYGWIN_TTY=1
export DISPLAY='yourhost:0.0'
export TERM=linux #this may not be necessary
./ssh -v yourhost
This should work. I do have DISPLAY set but I didn't know it mattered.
Let me know. I'm not at my PC right now so I can't test this out myself.
Pat




On Mon, 5 Jan 1998, Derek Young wrote:

> 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
> 
> 
> 
> 

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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