Bug 18686

Summary: /etc/hosts causes denial of localhost-only services
Product: [Retired] Red Hat Linux Reporter: Phil Venton <pventon>
Component: xinetdAssignee: Trond Eivind Glomsrxd <teg>
Status: CLOSED RAWHIDE QA Contact: David Lawrence <dkl>
Severity: medium Docs Contact:
Priority: medium    
Version: 7.0CC: dr, toddr, twaugh
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Hardware: i386   
OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2000-10-09 16:37:37 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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This one-liner fixes it for me. I don't think it's the right solution, but it shows where the problem is. none

Description Phil Venton 2000-10-09 10:06:49 UTC 
After a fresh install, xinetd will deny connections to any services listed
with "only_from = localhost", when attempting to connect from localhost.  

/etc/hosts contains the following:

127.0.0.1 localhost.localdomain localhost foo.bar.net foo

changing /etc/hosts to read, for example:

127.0.0.1 localhost.localdomain localhost
192.168.0.1 foo.bar.net foo

fixes the problem.

I suspect, in the first case, xinetd is resolving 127.0.0.1 to "foo" rather
than localhost, and disallowing the connect?

See also bug #17839
Comment 1 Tim Waugh 2000-10-09 11:01:21 UTC 
Created attachment 3904 [details]
This one-liner fixes it for me.  I don't think it's the right solution, but it shows where the problem is.
Comment 2 Trond Eivind Glomsrxd 2000-10-09 15:42:35 UTC 
Verified - it segfaults when doing access control.
Comment 3 Trond Eivind Glomsrxd 2000-10-09 16:10:05 UTC 
The oneliner does not fix the problem.
Comment 4 Tim Waugh 2000-10-09 16:22:42 UTC 
Huh?  It does; I just tried it again, this time without building with -g or
running with -d, which I did the first time.

The problem is that the str_addr comes from a static variable that's overwritten
with each entry parsed.  So the problem only shows itself on entries that are
not the last one to be read.

I installed -6 and telnet-server, and had just linuxconf-web and telnet in
xinetd.d.  I modified telnet to have 'only_from = localhost', and restarted
xinetd.  No problems.  When I moved linuxconf-web to xlinuxconf-web and restart
xinetd, I could telnet localhost.  After making the one line change and
restarting xinetd, I could.

There is another shallow copy a few lines above, so the one-liner clearly
doesn't _fix_ the problem entirely, but basically the problem is that shallow
rather than deep copies of that string are being performed.
Comment 5 Trond Eivind Glomsrxd 2000-10-09 16:37:33 UTC 
For me, it still segfaults. I agree that the issue is shallow copies, which is
why I'm currently going though it with njamd.
Comment 6 Trond Eivind Glomsrxd 2000-10-17 16:14:36 UTC 
Fixed in xinetd-2.1.8.9pre11-1
Comment 7 Crutcher Dunnavant 2001-03-15 22:33:09 UTC 
*** Bug 20516 has been marked as a duplicate of this bug. ***