Bug 981788 - TCP Wrapper is issuing a message during IPv6 connection via ssh/sftp
TCP Wrapper is issuing a message during IPv6 connection via ssh/sftp
Product: Fedora
Classification: Fedora
Component: tcp_wrappers (Show other bugs)
Unspecified Unspecified
unspecified Severity unspecified
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Assigned To: Petr Lautrbach
Fedora Extras Quality Assurance
Depends On:
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Reported: 2013-07-05 16:03 EDT by Erik Terwan
Modified: 2013-08-15 08:12 EDT (History)
1 user (show)

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Doc Type: Bug Fix
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Last Closed: 2013-08-15 08:12:59 EDT
Type: Bug
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Description Erik Terwan 2013-07-05 16:03:04 EDT
When I use sftp to make a connection via IPv6, I get the message: "Received message too long 1230009910". After that, sftp terminates.

Why? To answer my own question: when I use ssh to connect, I get the message: "IPv6 addr/mask: ::1/128" (the connection is local). Via IPv4 no message is given. So Where does the message "IPv6 addr/mask: ::1/128" originate? After a little searching I found that /usr/lib/libwrap.so.0.7.6 was the culprit.

When I use "ALL: [::1/128]" in /etc/hosts.allow, the message appears, and when I use "ALL: LOCAL", I don't reveive the message.

I found out about this problem because Nautilus (aftp) timed out after a very long time (and no connection was made). This problem was introduced in Fedora 19. In Fedora 18 I used "sftp://root@localhost/" as a bookmark, and I couldn't connect after the update to Fedora 19.

But why is libwrap issuing a message in IPv6 anyway? I see no reason for it (since it doesn't for IPv4).

Comment 1 Erik Terwan 2013-07-05 16:43:20 EDT
Forgot to mention that sftp doesn't seem to like messages issued during connection setup (according to http://www.snailbook.com/faq/sftp-corruption.auto.html). The number in the message "Received message too long 1230009910" is decimal and means:

1230009910 (decimal) = 49507636 (hexadecimal) = "IPv6" (ASCII).

This text is the first four characters in the string "IPv6 addr/mask: ::1/128".
Comment 2 Petr Lautrbach 2013-07-08 03:04:19 EDT
This is most probably as issue as bug #977995. I'm working on it and I'll push an update asap. Thanks for the report.
Comment 3 Petr Lautrbach 2013-08-15 08:12:59 EDT
I believe that this issue is fixed by 
https://admin.fedoraproject.org/updates/FEDORA-2013-12660/tcp_wrappers-7.6-74.fc19 update. Feel free to reopen this bug if the problem still persists.

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