Bug 83719 – hosts.allow IPaddr/mask wrongly interpreted

Bug 83719 - hosts.allow IPaddr/mask wrongly interpreted

Summary:	hosts.allow IPaddr/mask wrongly interpreted

Status:	CLOSED NOTABUG

Aliases:	None

Product:	Red Hat Linux
Classification:	Retired
Component:	tcp_wrappers (Show other bugs)
Sub Component:
Version:	8.0
Hardware:	i386 Linux

Priority	medium Severity low
Target Milestone:	---
Target Release:	---
Assigned To:	Florian La Roche
QA Contact:	David Lawrence
Docs Contact:

URL:
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Depends On:
Blocks:
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Reported:	2003-02-07 11:14 EST by Graham King
Modified:	2007-04-18 12:50 EDT (History)
CC List:	0 users

See Also:
Fixed In Version:
Doc Type:	Bug Fix
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:	2003-02-19 11:03:42 EST
Type:	---
Regression:	---
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Documentation:	---
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oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
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Description Graham King 2003-02-07 11:14:02 EST

From Bugzilla Helper:
User-Agent: Mozilla/5.0 Galeon/1.2.6 (X11; Linux i686; U;) Gecko/20020830

Description of problem:
man hosts.allow says:
"An  expression of the form ï¿½n.n.n.n/m.m.m.mï¿½ is interpreted as a
 ï¿½net/maskï¿½ pair. An IPv4 host address is  matched  if  ï¿½netï¿½  is
 equal  to  the  bitwise  AND  of the address and the ï¿½maskï¿½."

However, portmap is denied to host aaa.bbb.ccc.ddd/255.255.255.255, 
suggesting that the mask is wrongly applied.


Version-Release number of selected component (if applicable):


How reproducible:
Didn't try

Steps to Reproduce:

    On an NFS server host, /etc/hosts.deny contains:
ALL:ALL

/etc/hosts.allow contains (IP addresses sanitised):
portmap:ppp.qqq.rrr.sss/255.255.255.0,aaa.bbb.ccc.ddd/255.255.255.255
rpc.mountd:ppp.qqq.rrr.sss/255.255.255.0,aaa.bbb.ccc.ddd/255.255.255.255

An attempt to mount an NFS volume onto aaa.bbb.ccc.ddd gives the following in
the syslog on the NFS server host:
portmap[30168]: connect from aaa.bbb.ccc.ddd to getport(mountd): request from
unauthorized host

However, after changing the mask in hosts.allow to 255.255.255.254 the mount
attempt succeeds.

nfs-utils-1.0.1-2
tcp_wrappers-7.6-23

Additional info:

Comment 1 Thomas Woerner 2003-02-19 11:03:42 EST

This is no bug:

> man hosts.allow
    ...
    An  expression of the form ân.n.n.n/m.m.m.mÂ´ is interpreted as a
    ânet/maskÂ´ pair. An IPv4 host address is  matched  if  ânetÂ´  is
    equal  to  the  bitwise  AND  of the address and the âmaskÂ´. For
    example,  the  net/mask   pattern   â131.155.72.0/255.255.254.0Â´
    matches  every  address  in  the  range  â131.155.72.0Â´  through
    â131.155.73.255Â´.
    ...

Do not use net/mask pair for a single host.

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