Debian Bug report logs - #1039613
nmap breaks udptunnel autopkgtest: UDPTunnel communication failed

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Paul Gevers <elbrus@debian.org>

To: submit@bugs.debian.org

Subject: nmap breaks udptunnel autopkgtest: UDPTunnel communication failed

Date: Tue, 27 Jun 2023 21:40:14 +0200

[Message part 1 (text/plain, inline)]

Source: nmap, udptunnel
Control: found -1 nmap/7.94+dfsg1-1
Control: found -1 udptunnel/1.1-9
Severity: serious
Tags: sid bookworm
User: debian-ci@lists.debian.org
Usertags: breaks needs-update

Dear maintainer(s),

With a recent upload of nmap the autopkgtest of udptunnel fails in 
testing when that autopkgtest is run with the binary packages of nmap 
from unstable. It passes when run with only packages from testing. In 
tabular form:

                       pass            fail
nmap                   from testing    7.94+dfsg1-1
udptunnel              from testing    1.1-9
all others             from testing    from testing

I copied some of the output at the bottom of this report.

Currently this regression is blocking the migration of nmap to testing 
[1]. Due to the nature of this issue, I filed this bug report against 
both packages. Can you please investigate the situation and reassign the 
bug to the right package?

More information about this bug and the reason for filing it can be found on
https://wiki.debian.org/ContinuousIntegration/RegressionEmailInformation

Paul

[1] https://qa.debian.org/excuses.php?package=nmap

https://ci.debian.net/data/autopkgtest/testing/amd64/u/udptunnel/34896613/log.gz

33s udp        0      0 127.0.0.1:5500          0.0.0.0:*
36s tcp        0      0 0.0.0.0:6491            0.0.0.0:* 
LISTEN
39s udp        0      0 0.0.0.0:6661            0.0.0.0:* 
           39s 1,7d0
39s < THIS
39s <  IS
39s <   THE
39s <    DATA
39s <     SEND
39s <      OVER
39s <       UDPTunnel
39s UDPTunnel communication failed
39s ending 
/tmp/autopkgtest-lxc.mfhn3ylp/downtmp/build.Ils/src/debian/tests/validation 
with status 1
39s /tmp/autopkgtest-lxc.mfhn3ylp/downtmp/wrapper.sh: Killing leaked 
background processes: 1576 1580  39s     PID TTY      STAT   TIME COMMAND
39s    1576 ?        S      0:00 udptunnel -s 6491 127.0.0.1 5500
39s    1580 ?        S      0:00 udptunnel -c 127.0.0.1 6491 127.0.0.1 6661
40s autopkgtest [00:15:31]: test validation

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Message #18 received at 1039613@bugs.debian.org (full text, mbox, reply):

From: Paul Wise <pabs@debian.org>

To: 1039613@bugs.debian.org, Paul Gevers <elbrus@debian.org>, nmap@packages.debian.org, udptunnel@packages.debian.org

Subject: Re: nmap breaks udptunnel autopkgtest: UDPTunnel communication failed

Date: Sun, 23 Jul 2023 17:07:48 +0800

[Message part 1 (text/plain, inline)]

On Tue, 27 Jun 2023 21:40:14 +0200 Paul Gevers wrote:

> Source: nmap, udptunnel
> Control: found -1 nmap/7.94+dfsg1-1
> Control: found -1 udptunnel/1.1-9
...
> With a recent upload of nmap the autopkgtest of udptunnel fails in 
> testing when that autopkgtest is run with the binary packages of nmap 
> from unstable. It passes when run with only packages from testing.

I think this is likely to be a bug in nmap ncat, when I remove
udptunnel from the script by connecting ncat directly to ncat,
then the failure still happens with the autopkgtest.

I was able to reproduce this issue outside a chroot. I have attached a
pair of scripts; bad fails and good succeeds. In the good case, I use
`sleep` to hold stdin of `ncat -l` open for 2s, in the bad case I let
it use the stdin provided by the shell (a GNOME terminal pty here).

Looking at the diff between the verbose logs is interesting.
In the good case one select fd is ready and one becomes ready later,
the latter one gets used, but in the bad case both fds appear to be
ready immediately but neither of them get used.

-NCAT DEBUG: select returned 1 fds ready
-NCAT DEBUG: fd 3 is ready
-NCAT DEBUG: selecting, fdmax 3
-NCAT DEBUG: select returned 1 fds ready
+NCAT DEBUG: select returned 2 fds ready

So the issue can be worked around in the udptunnel script by piping
sleep to the ncat listener instead of launching ncat and then sleeping,
or the ncat change that caused this can get bisected and fixed.

-- 
bye,
pabs

https://wiki.debian.org/PaulWise

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Message #23 received at 1039613@bugs.debian.org (full text, mbox, reply):

From: Gordon Fyodor Lyon <fyodor@nmap.org>

To: Paul Wise <pabs@debian.org>, 1039613@bugs.debian.org

Cc: Paul Gevers <elbrus@debian.org>, nmap@packages.debian.org, udptunnel@packages.debian.org

Subject: Re: Bug#1039613: nmap breaks udptunnel autopkgtest: UDPTunnel communication failed

Date: Sun, 23 Jul 2023 09:51:39 -0700

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Thanks Paul.  We did make some changes in Nmap 7.94 which could have caused
regressions.  I've opened an issue for this on our upstream tracker (
https://github.com/nmap/nmap/issues/2685).  Please let us know if you
figure anything else out.

-Gordon

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Message #30 received at 1039613@bugs.debian.org (full text, mbox, reply):

From: Samuel Henrique <samueloph@debian.org>

To: Gordon Fyodor Lyon <fyodor@nmap.org>

Cc: Paul Wise <pabs@debian.org>, 1039613@bugs.debian.org, Paul Gevers <elbrus@debian.org>, nmap@packages.debian.org, udptunnel@packages.debian.org

Subject: Re: Bug#1039613: nmap breaks udptunnel autopkgtest: UDPTunnel communication failed

Date: Tue, 25 Jul 2023 21:38:53 +0100

After some investigation I found out the commit that introduces the
regression[0].

I have added a comment to the GitHub issue with the details:
https://github.com/nmap/nmap/issues/2685#issuecomment-1650519127

There's also an interesting finding that reproduction can only be
achieved through scripts, I wasn't able to reproduce it manually on an
interactive bash session.

[0] https://github.com/nmap/nmap/commit/4e6c8feb153c0c9ff8a68cd841669d650319ab45

Thank you, everyone!

-- 
Samuel Henrique <samueloph>

Message #35 received at 1039613-close@bugs.debian.org (full text, mbox, reply):

From: Debian FTP Masters <ftpmaster@ftp-master.debian.org>

To: 1039613-close@bugs.debian.org

Subject: Bug#1039613: fixed in nmap 7.94+dfsg1-3

Date: Thu, 27 Jul 2023 20:57:47 +0000

Source: nmap
Source-Version: 7.94+dfsg1-3
Done: Samuel Henrique <samueloph@debian.org>

We believe that the bug you reported is fixed in the latest version of
nmap, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1039613@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Samuel Henrique <samueloph@debian.org> (supplier of updated nmap package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

Format: 1.8
Date: Thu, 27 Jul 2023 20:09:55 +0100
Source: nmap
Architecture: source
Version: 7.94+dfsg1-3
Distribution: unstable
Urgency: medium
Maintainer: Debian Security Tools <team+pkg-security@tracker.debian.org>
Changed-By: Samuel Henrique <samueloph@debian.org>
Closes: 1011638 1039613
Changes:
 nmap (7.94+dfsg1-3) unstable; urgency=medium
 .
   [ Samuel Henrique ]
   * d/p/upstream-Ncat-server-udp...: New patch to fix UDP server listener
     (closes: #1039613)
 .
   [ Wookey ]
   * d/clean: Create file and add build artifact to it (closes: #1011638)
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 9360474ade2d683b2b140752be6871c33c05c31c 7567752 nmap_7.94+dfsg1.orig.tar.xz
 6c7dfc91d1e6f607ac8d37891d0b2b1e78824211 34688 nmap_7.94+dfsg1-3.debian.tar.xz
 d989c0c9d3d287a7a00803f6de9bbe5574667fc8 10300 nmap_7.94+dfsg1-3_amd64.buildinfo
Checksums-Sha256:
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 99aca1ab32dcc6795a580e5547860b8a38ead6839ea43e40da6fb24a528d8737 34688 nmap_7.94+dfsg1-3.debian.tar.xz
 a1792314d2d71e03fc45e8291459fd7de0c3bf7685902730faa7a113f30ee9cb 10300 nmap_7.94+dfsg1-3_amd64.buildinfo
Files:
 e89f45449699863eee6cd3d07bec9bde 2275 net optional nmap_7.94+dfsg1-3.dsc
 ef8257179ff39cb26e0c9d1d9c84e125 7567752 net optional nmap_7.94+dfsg1.orig.tar.xz
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 3047da9db52540b55d26df4fcc138d68 10300 net optional nmap_7.94+dfsg1-3_amd64.buildinfo

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