openssh unix dev - Jan 2008 - OpenSSH for OS/390

I have been trying to compile OpenSSH_4.7p1 for OS/390 and got really stuck. IBM
released a build of v3.8.1p1 several years ago, but I do not know whether anyone
else has ever managed to compile it for OS/390 or OS/z.

The first problem is that the build apparently performs ssh transport exchange
using EBCDIC character encoding instead of ASCII (which breaks RFC 4253) and I
am not sure how to do the conversion properly so that it will not corrupt truely
binary data.

The second problem is that connection fails even for ssh client and deamon that
belong to the same build. Here is the output of sshd (the client has received
SSH2_MSG_SERVICE_ACCEPT and is running dispatch_run):

debug1: attempt 0 failures 0
debug3: mm_getpwnamallow entering
debug3: mm_request_send entering: type 6
debug3: mm_getpwnamallow: waiting for MONITOR_ANS_PWNAM
debug3: mm_request_receive_expect entering: type 7
debug3: mm_request_receive entering
debug3: monitor_read: checking request 6
debug3: mm_answer_pwnamallow
debug3: Trying to reverse map address 10.55.27.21.
debug2: parse_server_config: config reprocess config len 209
debug3: mm_answer_pwnamallow: sending MONITOR_ANS_PWNAM: 1
debug3: mm_request_send entering: type 7
debug2: monitor_read: 6 used once, disabling now
debug3: mm_request_receive entering
mm_getpwnamallow: option block size mismatch

It appears that some of the debugging messages are coming from the parent thread
and some from the child thread. All I can add is that the buffer "m"
in mm_getpwnamallow() has alloc=32768, offset=52, end=10055 and also that
buffer_get_string() returns len=7, which is rather different from
sizeof(*newopts)=9988, indeed. I am really lost here and cannot figure out what
is wrong.

Can anybody advise me on how to fix it or perhaps there is already a patch?

Thanks,
Eugene
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On Thu, Jan 24, 2008 at 09:50:22PM -0800, E Pivovarov
wrote:
> I have been trying to compile OpenSSH_4.7p1 for OS/390 and got really
> stuck. IBM released a build of v3.8.1p1 several years ago, but I do
> not know whether anyone else has ever managed to compile it for OS/390
> or OS/z.
> The first problem is that the build apparently performs ssh transport
> exchange using EBCDIC character encoding instead of ASCII (which breaks
> RFC 4253) and I am not sure how to do the conversion properly so that
> it will not corrupt truely binary data.
I vaguely recall someone posting about that quite some time back, I would
check the list archive... ah, here we are:
http://marc.info/?l=openssh-unix-dev&m=106561577824857&w=2
> The second problem is that connection fails even for ssh client and
> deamon that belong to the same build. Here is the output of sshd (the
> client has received SSH2_MSG_SERVICE_ACCEPT and is running dispatch_run):
[...]
> It appears that some of the debugging messages are coming from the
> parent thread and some from the child thread. All I can add is that the
> buffer "m" in mm_getpwnamallow() has alloc=32768, offset=52,
end=10055 and
> also that buffer_get_string() returns len=7, which is rather different
> from sizeof(*newopts)=9988, indeed. I am really lost here and cannot
> figure out what is wrong.
That looks pretty wrong but I can't think of any reason it would happen.
Does this patch make any difference, what is the output of the XXX lines?

Index: monitor.c
==================================================================RCS file:
/usr/local/src/security/openssh/cvs/openssh/monitor.c,v
retrieving revision 1.126
diff -u -p -r1.126 monitor.c
--- monitor.c	2 Dec 2007 12:02:15 -0000	1.126
+++ monitor.c	27 Jan 2008 11:05:01 -0000
@@ -607,6 +607,7 @@ mm_answer_pwnamallow(int sock, Buffer *m
 	char *username;
 	struct passwd *pwent;
 	int allowed = 0;
+	u_int len;
 
 	debug3("%s", __func__);
 
@@ -645,7 +646,9 @@ mm_answer_pwnamallow(int sock, Buffer *m
 	buffer_put_cstring(m, pwent->pw_shell);
 
  out:
-	buffer_put_string(m, &options, sizeof(options));
+	len = sizeof(options);
+	logit("XXX sending option block, size %u", len);
+	buffer_put_string(m, &options, len);
 	if (options.banner != NULL)
 		buffer_put_cstring(m, options.banner);
 	debug3("%s: sending MONITOR_ANS_PWNAM: %d", __func__, allowed);
Index: monitor_wrap.c
==================================================================RCS file:
/usr/local/src/security/openssh/cvs/openssh/monitor_wrap.c,v
retrieving revision 1.76
diff -u -p -r1.76 monitor_wrap.c
--- monitor_wrap.c	2 Dec 2007 12:02:15 -0000	1.76
+++ monitor_wrap.c	27 Jan 2008 11:02:04 -0000
@@ -240,8 +240,10 @@ mm_getpwnamallow(const char *username)
 out:
 	/* copy options block as a Match directive may have changed some */
 	newopts = buffer_get_string(&m, &len);
+	logit("XXX got option block size %u", len);
 	if (len != sizeof(*newopts))
-		fatal("%s: option block size mismatch", __func__);
+		fatal("%s: option block size mismatch expected %u got %u",
+		    __func__, sizeof(*newopts), len);
 	if (newopts->banner != NULL)
 		newopts->banner = buffer_get_string(&m, NULL);
 	copy_set_server_options(&options, newopts, 1);

-- 
Darren Tucker (dtucker at zip.com.au)
GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4  37C9 C982 80C7 8FF4 FA69
    Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.