Bug 126242 - xinetd displays a banner twice
xinetd displays a banner twice
Status: CLOSED RAWHIDE
Product: Fedora
Classification: Fedora
Component: xinetd (Show other bugs)
2
All Linux
medium Severity medium
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Assigned To: Jay Fenlason
Brock Organ
:
Depends On:
Blocks:
  Show dependency treegraph
 
Reported: 2004-06-17 18:11 EDT by Dax Kelson
Modified: 2014-08-31 19:26 EDT (History)
1 user (show)

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Doc Type: Bug Fix
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Clone Of:
Environment:
Last Closed: 2004-06-18 15:51:35 EDT
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RHEL 7.3 requirements from Atomic Host:
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Description Dax Kelson 2004-06-17 18:11:35 EDT
Description of problem:

I'm just testing Xinetd on FC2 and I discovered this behavior change
versus FC1/RHEL3.

I added the following lines to the /etc/xinetd.d/telnet configuration
file:

        log_on_success  += DURATION
        instances       = 5
        per_source      = 1
        banner          = /etc/go.away.banner


So that the complete file now looks like this:
service telnet
{
        disable = no
        flags           = REUSE
        socket_type     = stream
        wait            = no
        user            = root
        server          = /usr/sbin/in.telnetd
        log_on_failure  += USERID
        log_on_success  += DURATION
        instances       = 5
        per_source      = 1
        banner          = /etc/go.away.banner
}


I did a '/etc/init.d/xinetd reload' and created the file
/etc/go.away.banner. It has two lines in it as you can see.

[root@station1 root]# cat /etc/go.away.banner
This is a secured system, unauthorized access is prohibited.
All access is logged.
[root@station1 root]#

I then telneted to the box from another FC2 host.

This was displayed:

[root@station2 root]# telnet station1
Trying 10.100.0.1...
Connected to station1.example.com (10.100.0.1).
Escape character is '^]'.
This is a secured system, unauthorized access is prohibited.
All access is logged.
This is a secured system, unauthorized access is prohibited.
All access is logged.
Fedora Core release 2 (Tettnang)
Kernel 2.6.5-1.358smp on an i686
login:

(note the double display of the banner).
Comment 1 Jay Fenlason 2004-06-18 15:51:35 EDT
Ayup.  That's a bug.  (What's happening is xinetd "writes" the data 
before it forks (to spawn the telnet server), then both processes 
flush the buffered-but-unwritten banner data, resulting in two 
copies of it going to the client.  banner_fail suffers from the same 
problem, but the symptom is that no banner data shows up at all.)  I 
just built fixed rpms which should show up in rawhide Real Soon Now. 

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