Mailing List Archive: [Bug 1012] Trouble creating remote port forwarding to ssh.com 2.4.0 server.

[Bug 1012] Trouble creating remote port forwarding to ssh.com 2.4.0 server.

Apr 7, 2005, 8:48 AM

Post #1 of 5 (169 views)

http://bugzilla.mindrot.org/show_bug.cgi?id=1012

Summary: Trouble creating remote port forwarding to ssh.com 2.4.0
server.
Product: Portable OpenSSH
Version: 4.0p1
Platform: All
OS/Version: All
Status: NEW
Keywords: patch
Severity: normal
Priority: P2
Component: ssh
AssignedTo: openssh-bugs@mindrot.org
ReportedBy: daveroth@acm.org

I'm having a problem with OpenSSH_4.0p1 when trying to do remote port
forwards to a server running SSH Secure Shell 2.4.0. The problem appears
to be that 2.4.0 chokes on bind addresses that aren't numeric addresses,
such as "localhost" and "".

The following commands are failing for me from the 4.0p1 client to the
2.4.0 server:

ssh -R 50000:localhost:50000 server
ssh -R localhost:50000:localhost:50000 server
ssh -R :50000:localhost:50000 server
ssh -R \*:50000:localhost:50000 server

although these commands work just fine:

ssh -R 127.0.0.1:50000:localhost:50000 server
ssh -R 0.0.0.0:50000:localhost:50000 server
ssh -R 192.168.1.1:50000:localhost:50000 server

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[Bug 1012] Trouble creating remote port forwarding to ssh.com 2.4.0 server. [ In reply to ]

bugzilla-daemon at mindrot

Apr 7, 2005, 8:50 AM

Post #2 of 5 (176 views)

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------- Additional Comments From daveroth@acm.org 2005-04-08 02:50 -------
Created an attachment (id=870)
--> (http://bugzilla.mindrot.org/attachment.cgi?id=870&action=view)
Default to 0.0.0.0 as bind address for ssh.com 2.4.0 servers.

The attached patch solves the problem for me. It sends "0.0.0.0" as the
address_to_bind for these cases

ssh -R 50000:localhost:50000 server
ssh -R :50000:localhost:50000 server
ssh -R \*:50000:localhost:50000 server

but still passes through the specified address for cases like

ssh -R 192.168.1.1:50000:localhost:50000 server

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[Bug 1012] Trouble creating remote port forwarding to ssh.com 2.4.0 server. [ In reply to ]

bugzilla-daemon at mindrot

Apr 7, 2005, 8:51 AM

Post #3 of 5 (171 views)

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http://bugzilla.mindrot.org/show_bug.cgi?id=1012

daveroth@acm.org changed:

What |Removed |Added
----------------------------------------------------------------------------
Attachment #870|Default to 0.0.0.0 as bind |Default to 0.0.0.0 as bind
description|address for ssh.com 2.4.0 |address for ssh.com 2.4.0
|servers. |servers.

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[Bug 1012] Trouble creating remote port forwarding to ssh.com 2.4.0 server. [ In reply to ]

bugzilla-daemon at mindrot

Apr 17, 2005, 9:49 PM

Post #4 of 5 (167 views)

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http://bugzilla.mindrot.org/show_bug.cgi?id=1012

------- Additional Comments From djm@mindrot.org 2005-04-18 15:49 -------
(From update of attachment 870)
>diff -Naur openssh-4.0p1-1/channels.c openssh-4.0p1-2/channels.c
>--- openssh-4.0p1-1/channels.c 2005-03-01 02:24:33.000000000 -0800
>+++ openssh-4.0p1-2/channels.c 2005-04-04 17:27:44.230250000 -0700
>@@ -2370,9 +2370,15 @@
> if (compat20) {
> const char *address_to_bind;
> if (listen_host == NULL)
>- address_to_bind = "localhost";
>+ if (datafellows & SSH_BUG_NUMERICRFWDADDR)
>+ address_to_bind = "0.0.0.0";

I think that should be "127.0.0.1", not "0.0.0.0". Or did you have a
specific reason for changing this?

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[Bug 1012] Trouble creating remote port forwarding to ssh.com 2.4.0 server. [ In reply to ]

bugzilla-daemon at mindrot

Apr 18, 2005, 8:29 AM

Post #5 of 5 (167 views)

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------- Additional Comments From daveroth@acm.org 2005-04-19 02:29 -------
(In reply to comment #2)
> (From update of attachment 870 [edit])
> >diff -Naur openssh-4.0p1-1/channels.c openssh-4.0p1-2/channels.c
> >--- openssh-4.0p1-1/channels.c 2005-03-01 02:24:33.000000000 -0800
> >+++ openssh-4.0p1-2/channels.c 2005-04-04 17:27:44.230250000 -0700
> >@@ -2370,9 +2370,15 @@
> > if (compat20) {
> > const char *address_to_bind;
> > if (listen_host == NULL)
> >- address_to_bind = "localhost";
> >+ if (datafellows & SSH_BUG_NUMERICRFWDADDR)
> >+ address_to_bind = "0.0.0.0";
>
> I think that should be "127.0.0.1", not "0.0.0.0". Or did you have a
> specific reason for changing this?

I did have 127.0.0.1 at first, but I changed it for two reasons. One was that I
think 0.0.0.0 was the old pre-4.0 behavior. The second was that I think
127.0.0.1 will only work for IPv4. I'm no expert here, and I'm not even sure
ssh.com 2.4 works with IPv6.

I have no problem with changing this to 127.0.0.1 if the above reasons make no
sense.

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