Date: Sat, 21 Oct 2000 17:59:52 +0400 (MSD) From: yar@comp.chem.msu.su To: FreeBSD-gnats-submit@freebsd.org Subject: kern/22185: Identical IP addresses on two broadcast interfaces Message-ID: <200010211359.e9LDxqf00443@yar.chem.msu.su>
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>Number: 22185
>Category: kern
>Synopsis: Identical IP addresses on two broadcast interfaces
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Sat Oct 21 07:10:01 PDT 2000
>Closed-Date:
>Last-Modified:
>Originator: Yar Tikhiy
>Release: FreeBSD 4.1-STABLE i386
>Organization:
Moscow State University
>Environment:
The bug seems to exist in all branches.
>Description:
It's possible to add two absolutely identical IP addresses
to two different broadcast interfaces.
I guess it would be possible to add different addresses from
the same network, too.
The problem arises from in_control()/in_ifinit() leaving the
address installed even if adding the link-layer route fails.
>How-To-Repeat:
yar# ifconfig fxp0 10.1.1.1
yar# ifconfig fxp1 10.1.1.1
ifconfig: ioctl (SIOCAIFADDR): File exists
yar# ifconfig fxp0
fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet 10.1.1.1 netmask 0xff000000 broadcast 10.255.255.255
ether 00:d0:b7:60:63:da
media: autoselect (100baseTX) status: active
supported media: autoselect 100baseTX <full-duplex> 100baseTX 10baseT/UT
P <full-duplex> 10baseT/UTP
yar# ifconfig fxp1
fxp1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
inet 10.1.1.1 netmask 0xff000000 broadcast 10.255.255.255
ether 00:a0:c9:66:67:4d
media: autoselect (100baseTX) status: active
supported media: autoselect 100baseTX <full-duplex> 100baseTX 10baseT/UT
P <full-duplex> 10baseT/UTP
>Fix:
Maybe, the code should try to add the link layer route first,
and assign the address to the interface only if adding
the route succeeded?
>Release-Note:
>Audit-Trail:
>Unformatted:
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