Can't ssh from FreeBSD 10 host to FreeBSD 7 jail

[Mario Zorin]

Hi,

I'm having a very strange issue with my jails. I have a FreeBSD-7 jail that
worked normally on FreeBSD-9 host, and I could ssh to it.

After moving the host to FreeBSD-10, I can't ssh to 7 jail anymore.

>From the host side:
PTY allocation request failed on channel 0
Warning: no access to tty (Bad file descriptor).
Thus no job control in this shell.

>From the jail log:
Apr 20 22:25:50 xxx sshd[75065]: error: openpty: Resource temporarily
unavailable
Apr 20 22:25:50 xxx sshd[75065]: error: session_pty_req: session 0 alloc
failed

script within the jail doesn't work as well:
# script /tmp/a
script: openpty: Resource temporarily unavailable

I read a lot of documents about what can cause this situation and nothing
apply to me. One by one:

* Some people had a problem with devfs.rules (jail's /dev/pts/* were
hidden). This is not a case in my jail (I set 0777 permissions for the
debugging purposes and to test devfs.rules):

add path 'pts/*' unhide mode 0777 group wheel
add type tty unhide mode 0777 group wheel

In the jail:

# ls -la dev/pts/
total 1
drwxrwxrwx   2 root    wheel   512 Apr 21 01:48 .
dr-xr-xr-x  11 root    wheel   512 Apr 21 01:48 ..
crwxrwxrwx   1 user  wheel  0x67 Apr 21 02:25 0
crwxrwxrwx   1 user  wheel  0xbf Apr 21 02:26 1
crwxrwxrwx   1 user  wheel  0xca Apr 21 02:28 2

# ls -la /dev/*tty*
crwxrwxrwx  1 root  wheel    0,  69 Apr 20 22:31 /dev/ttyv0
crwxrwxrwx  1 root  wheel    0,  70 Apr 20 00:59 /dev/ttyv1
crwxrwxrwx  1 root  wheel    0,  71 Apr 20 00:59 /dev/ttyv2
crwxrwxrwx  1 root  wheel    0,  72 Apr 20 00:59 /dev/ttyv3
crwxrwxrwx  1 root  wheel    0,  73 Apr 20 00:59 /dev/ttyv4
crwxrwxrwx  1 root  wheel    0,  74 Apr 20 00:59 /dev/ttyv5
crwxrwxrwx  1 root  wheel    0,  75 Apr 20 00:59 /dev/ttyv6
crwxrwxrwx  1 root  wheel    0,  76 Apr 20 00:59 /dev/ttyv7
crwxrwxrwx  1 root  wheel    0,  77 Apr 20 00:59 /dev/ttyv8
crwxrwxrwx  1 root  wheel    0,  78 Apr 20 00:59 /dev/ttyv9
crwxrwxrwx  1 root  wheel    0,  79 Apr 20 00:59 /dev/ttyva
crwxrwxrwx  1 root  wheel    0,  80 Apr 20 00:59 /dev/ttyvb

* Some people solved the problem my upgrading ssh software inside a jail.
That didn't help in my case. In my jail:
OpenSSH_5.2p1
(the latest available for 7-STABLE)

I can't build the newest 6.6p1 on FreeBSD-7.

So, does anybody know why sshd in the jail can't start a ssh session? I
note that ssh _from_ jail _to_ host works.

MZ