Post, Mark K wrote:
Brad,

Thanks for the suggestion.  It didn't provide any answers (yet), but it
certainly raised a whole bunch more questions.  Running ldconfig (for
the umpteenth time) didn't help.  Here's the tail end of the strace
output.  What really strikes me is that it shows process 3142 trying to
open a lot of files and getting "-1 ENOENT" as the return code, when all
those files and directories really do exist on my system (except for the
/usr/lib/libnss_dns.so.2 one).  Then it generates a SIGSEGV, not the
EINTR you thought might be the case.  (What mainframers call a S0C4
abend.)  This whole problem is getting stranger and stranger.

The 0C4 was my first thought; memory protection, if my memory doesn't
fail me.

The ssh closing the connexion can arise for several reasons. Some
legitimate ones:
If you try to connect to my ssh servers, that's what you will get
because you will fail the tests in /etc/hosts.allow and /etc/hosts.deny.

You could get it connecting to an account with no ~ if only key-exchange
authentication is allowed.

You could get it if password authentication is required but failing due
to an incompatible configuration (eg it's "required" because nothing
else has worked, but the configuration doesn't allow it.

This last seems your problem, though it's not allowed because the
authentication is failing, albeit with an "0c4."

If you're not using PAM, then what mechanism are you using to check
passwords?

If you are using PAM, then authentication could be failing through
problems in LDAP, NIS, whatever you use to store passwords.

I can't comment sensibly on the strace, below, without knowing what pid
3142 is (and possbly not then). It does seem to me using "ssh -v" under
strace is a little bit of overkill, and I'd also be running tcpdump or
wireshark to see what's on the wire.

Not that there's any excuse for the 0c4, that's a bug in something.




[pid  3142] <... select resumed> )      = 1 (in [3])
[pid  3142] read(3,
"\372\276\211\263{\22\223\201\240\301\326c#\342\"\277\313"..., 8192) =
96
[pid  3142] write(2, "debug1: userauth-request for use"..., 93debug1:
userauth-request for user markkp service ssh-connection method
keyboard-interactive
) = 93
[pid  3142] write(2, "debug1: attempt 1 failures 1\r\n", 30debug1:
attempt 1 failures 1
) = 30
[pid  3142] write(2, "debug1: keyboard-interactive dev"..., 36debug1:
keyboard-interactive devs
) = 36
[pid  3142] write(2, "debug1: auth2_challenge: user=ma"..., 44debug1:
auth2_challenge: user=markkp devs=
) = 44
[pid  3142] write(2, "debug1: kbdint_alloc: devices \'\'"..., 34debug1:
kbdint_alloc: devices ''
) = 34
[pid  3142] write(2, "Failed keyboard-interactive for "..., 70Failed
keyboard-interactive for markkp from 127.0.0.1 port 1128 ssh2
) = 70
[pid  3142] getpeername(3, {sa_family=AF_INET6, sin6_port=htons(1128),
inet_pton(AF_INET6, "::ffff:127.0.0.1", &sin6_addr), sin6_flowinfo=0,
sin6_scope_id=0}, [28]) = 0
[pid  3142] open("/etc/protocols", O_RDONLY) = -1 ENOENT (No such file
or directory)
[pid  3142] getsockopt(3, SOL_IP, IP_OPTIONS, "", [0]) = 0
[pid  3142] socket(PF_FILE, SOCK_STREAM, 0) = 5
[pid  3142] fcntl64(5, F_GETFL)         = 0x2 (flags O_RDWR)
[pid  3142] fcntl64(5, F_SETFL, O_RDWR|O_NONBLOCK) = 0
[pid  3142] connect(5, {sa_family=AF_FILE, path="/var/run/nscd/socket"},
110) = -1 ENOENT (No such file or directory)
[pid  3142] close(5)                    = 0
[pid  3142] socket(PF_FILE, SOCK_STREAM, 0) = 5
[pid  3142] fcntl64(5, F_GETFL)         = 0x2 (flags O_RDWR)
[pid  3142] fcntl64(5, F_SETFL, O_RDWR|O_NONBLOCK) = 0
[pid  3142] connect(5, {sa_family=AF_FILE, path="/var/run/nscd/socket"},
110) = -1 ENOENT (No such file or directory)
[pid  3142] close(5)                    = 0
[pid  3142] gettimeofday({1159112979, 455645}, NULL) = 0
[pid  3142] getpid()                    = 3142
[pid  3142] open("/etc/resolv.conf", O_RDONLY) = -1 ENOENT (No such file
or directory)
[pid  3142] uname({sys="Linux", node="linwiki", ...}) = 0
[pid  3142] open("/etc/host.conf", O_RDONLY) = -1 ENOENT (No such file
or directory)
[pid  3142] open("/etc/hosts", O_RDONLY) = -1 ENOENT (No such file or
directory)
[pid  3142] open("/etc/ld.so.cache", O_RDONLY) = -1 ENOENT (No such file
or directory)
[pid  3142] open("/lib/libnss_dns.so.2", O_RDONLY) = -1 ENOENT (No such
file or directory)
[pid  3142] stat64("/lib", 0x7fffcff8)  = -1 ENOENT (No such file or
directory)
[pid  3142] open("/usr/lib/libnss_dns.so.2", O_RDONLY) = -1 ENOENT (No
such file or directory)
[pid  3142] stat64("/usr/lib", 0x7fffcff8) = -1 ENOENT (No such file or
directory)
[pid  3142] --- SIGSEGV (Segmentation fault) @ 0 (0) ---
Process 3142 detached
<... read resumed> "\177\377\356X\177\377\355\350\177\377\356X", 4) =
-512
--- SIGCHLD (Child exited) @ 0 (0) ---
read(5, "", 4)                          = 0
write(2, "debug1: do_cleanup\r\n", 20debug1: do_cleanup
)  = 20
_exit(255)                              = ?


ls -ld /etc/resolv.conf /etc/host.conf /etc/hosts /etc/ld.so.cache
/lib/libnss_dns.so.2 /lib /usr/lib/libnss_dns.so.2 /usr/lib
-rw-r--r--   1 root root    27 1994-07-07 11:39 /etc/host.conf
-rw-r--r--   1 root root   664 2006-09-22 19:00 /etc/hosts
-rw-r--r--   1 root root 18503 2006-09-23 14:57 /etc/ld.so.cache
-rw-r--r--   1 root root    71 2006-09-22 15:33 /etc/resolv.conf
drwxr-xr-x   4 root root  4096 2006-09-22 18:05 /lib/
lrwxrwxrwx   1 root root    19 2006-09-22 15:15 /lib/libnss_dns.so.2 ->
libnss_dns-2.3.4.so*
drwxr-xr-x  18 root root 12288 2006-09-23 14:57 /usr/lib/


Mark Post

-----Original Message-----
From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of
Brad Hinson
Sent: Sunday, September 24, 2006 3:44 AM
To: LINUX-390@VM.MARIST.EDU
Subject: Re: OpenSSH Oddity

Looking at arlibnss_dns.so.2ch/s390/kernel/traps.c, do_trap(), I bet
interruption code
0x4 corresponds to EINTR 'interrupted system call'.  An strace of the
sshd process while you attempt to connect may help identify which
syscall is failing, if any.  I used:

# ps aux | grep sshd
root      1267  0.0  0.9  5224 2344 ?        Ss   Sep16
0:00 /usr/sbin/sshd
# strace -p 1267 -o /tmp/strace.out
Process 1267 attached - interrupt to quit
((connect with client))
^c
Process 1267 detached

I wonder if anything is returning -1..

Also, does it make a difference if you run 'ldconfig' on the target
system?  I tend to blame glibc for syscall errors, but maybe it's not
related.


On Sat, 2006-09-23 at 17:46 -0400, Post, Mark K wrote:

Nope, no differences in sshd_config, since that is delivered as part

of

the package, and Pat doesn't do PAM, so no PAM configuration files at
all.


Thanks for the suggestions to check,

Mark Post

-----Original Message-----
From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of
Marcy Cortes
Sent: Saturday, September 23, 2006 5:35 PM
To: LINUX-390@VM.MARIST.EDU
Subject: Re: OpenSSH Oddity

Is you sshd_config the same? How about the /etc/pam.d stuff?


Marcy Cortes

-----Original Message-----
From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of
Post, Mark K
Sent: Saturday, September 23, 2006 2:21 PM
To: LINUX-390@VM.MARIST.EDU
Subject: Re: [LINUX-390] OpenSSH Oddity

One other item of interest.  If I try to connect using keys, and not a
password, things work just fine.  But, as I said, when I am not using
keys, I don't even get prompted for a password, so it's something in

the

processing that's going wrong before it gets to asking for a password.


Mark Post

-----Original Message-----
From: Post, Mark K
Sent: Saturday, September 23, 2006 5:10 PM
To: 'Linux on 390 Port'
Subject: RE: OpenSSH Oddity

From my note:

I've checked the md5 checksums for all the files in the openssh and
openssl packages, as well as all the shared libraries the sshd

binary

uses.

So, not that I can tell.


Mark Post

-----Original Message-----
From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of
Rick Troth
Sent: Saturday, September 23, 2006 3:38 PM
To: LINUX-390@VM.MARIST.EDU
Subject: Re: OpenSSH Oddity

Target system has different run-time libs?

-- R;

On Sat, 23 Sep 2006, Post, Mark K wrote:


I'm having a very strange problem show up with OpenSSH 4.3p1.  On

the

development system where I built it, it works fine.  When I ship the
binary package to another Linux guest on the same z/VM system, it
doesn't work.  When I try to ssh into the system, the client gets a
"Connection closed by 192.168.0.20" message, without even being

prompted

for a password.  The sshd daemon on the other system throws off this
error in the kernel ring buffer (but keeps on running):
User process fault: interruption code 0x4 failing address: 40016000
CPU:    0    Not tainted
Process sshd (pid: 13181, task: 0152c000, ksp: 0152dd00) User PSW :
070dc000 c0006318 User GPRS: ffffffff 40017738 00010dd0 00000000
          00000000 ffffffff 7fffcfa8 40016f3c
          00000000 00000000 40016f3c 7fffcf68
          40017000 c0006164 c00064b2 7fffcf48 User ACRS: 40010870
00000000 00000000 00000000
          00000000 00000000 00000000 00000000
          00000000 00000000 00000000 00000000
          00000000 00000000 00000000 00000000 User Code: 50 00 70

00

a7 f4 ff ed 58 80 b0 d4 58 90 d0 40 58 20 80 00


I've checked the md5 checksums for all the files in the openssh and
openssl packages, as well as all the shared libraries the sshd

binary

uses.  They all match on both systems.  Even if I build the binary

on

the target system, I get the same results.  I'm at a loss to explain

why

it works fine on one system, but not others.  Anyone have any ideas
where to look further?


Thanks,

Mark Post


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Cheers
John

-- spambait
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