openssh unix dev - Apr 2003 - [Bug 536] no access to tty on Linux 2.0 and 2.4+libc5

http://bugzilla.mindrot.org/show_bug.cgi?id=536

stuge-openssh-unix-dev at cdy.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|no access to tty on Linux   |no access to tty on Linux
                   |2.0                         |2.0 and 2.4+libc5



------- Additional Comments From stuge-openssh-unix-dev at cdy.org  2003-04-09
14:40 -------
Adding that this is not 2.0 specific, I see the same behavior on 2.4 with libc5.



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------- Additional Comments From afuerst at cogidata.com  2003-04-11 20:16
-------
* This error also happens on Linux Kernel 2.2.22, glibc 2.3.1 with openssh-3.6p1
  and openssh-3.6.1p1. openssh-3.5p1 is the latest version running on this 
  system.

* It happens with users with "bash" as default shell.

* sshd -d => works

* #define STREAMS_PUSH_ACQUIRES_CTTY 1 => works

* The workaround from "Frank Adelstein" does not work.





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------- Additional Comments From fong at pigtail.net  2003-05-04 11:57 -------
Very similar problem on LRP due to an error that says 
(approximately, since I did a roll back to 3.4p1 and do not have access to a
compiler to recompile 3.6p1) "insufficient privilage to create tty", 
Will update the thread when I get the machine back.

Compile environment: Debian Slink



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------- Additional Comments From fong at pigtail.net  2003-05-04 13:40 -------
Compile environment: Debian Slink, kernel 2.2.12
Target environment: LRP, kernel 2.2.19, glibc 2.0

This works:
#define STREAMS_PUSH_ACQUIRES_CTTY 1 

This works:
modify line 318 of sshpty.c
if (ioctl(*ttyfd, TIOCSCTTY, 1) < 0)

Tested with 3.6p1 and 3.6.1.p1






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------- Additional Comments From dtucker at zip.com.au  2003-05-06 19:36 -------
Created an attachment (id=282)
 --> (http://bugzilla.mindrot.org/attachment.cgi?id=282&action=view)
Don't call setsid() on Linux 2.0 and 2.2

Please try the the attached patch.  It renames STREAMS_PUSH_ACQUIRES_CTTY ->
SSHD_ACQUIRES_CTTY and defines it for Linux 2.0 and 2.0.

The patch is against the CVS tree and you'll need to run
"autoreconf".	If you
don't have a CVS tree or autoconf handy you can try this snapshot instead:
http://www.zip.com.au/~dtucker/openssh/test/openssh-linux20_ctty.tar.gz



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------- Additional Comments From dtucker at zip.com.au  2003-05-06 19:38 -------
Make that "2.0 and 2.2" and does anyone know a good way of detecting
libc5?



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------- Additional Comments From dtucker at zip.com.au  2003-05-07 21:05 -------
Created an attachment (id=283)
 --> (http://bugzilla.mindrot.org/attachment.cgi?id=283&action=view)
cttytest.c: Test for broken Linux/glibc/openpty controlling terminal behaviour

OK, the data points we've got are:
broken: 2.0.34 kernel, unknown libc
broken: 2.4.? kernel, libc5
broken: 2.0.38 kernel, glibc 2.0.7 (Debian Slink)
working: kernel 2.4.18, glibc 2.3.2 (Redhat 8)

So it looks like a libc thing.	Searching the glibc ChangeLog:

1999-05-24  Ulrich Drepper  <drepper at cygnus.com>
	* login/openpty.c (openpty): Make sure pty does not because
	controlling TTY.

So it looks like openpty is the culprit.  I have attached a test program that
should detect this.  You made need to link with -lutil.

On Debian Slink:
$ gcc cttytest.c -lutil
$ ./a.out
Test failed: reacquired controlling tty

And on Redhat 8:
$ ./a.out 
Test passed.

I'll wrap it into a configure test and attach a patch.



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------- Additional Comments From stuge-openssh-unix-dev at cdy.org  2003-05-07
21:45 -------
Unfortunately I have migrated the 2.4.18/libc5 system to glibc 2.2.3 since my
comment, your test passes, as expected. I believe this test is a winner.



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dtucker at zip.com.au changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
 Attachment #282 is|0                           |1
           obsolete|                            |



------- Additional Comments From dtucker at zip.com.au  2003-05-07 21:59 -------
Created an attachment (id=284)
 --> (http://bugzilla.mindrot.org/attachment.cgi?id=284&action=view)
Add configure test for broken openpty() on Linux.

Please test.  You will need to run "autoreconf".  I have updated the
snapshot
mentioned in comment #10.

I had to move the -lutil stuff to before the platform-specific tests since the
openpty test needs libutil, I'm not sure about that from a style point of
view.



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dtucker at zip.com.au changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
 Attachment #284 is|0                           |1
           obsolete|                            |



------- Additional Comments From dtucker at zip.com.au  2003-05-08 19:51 -------
Created an attachment (id=285)
 --> (http://bugzilla.mindrot.org/attachment.cgi?id=285&action=view)
Set SSHD_ACQUIRES_CTTY unless openpty tests OK.

Similar to previous patch but inverts the sense of the test and adds a bit of
error checking.

Defining SSHD_ACQUIRES_CTTY is the safe option, so it's defined *unless*
we're
on a known-good configuration.	(The previous test would not set it if the
compilation of the test failed and would produce a partially-broken sshd in
that case).



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dtucker at zip.com.au changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch





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