system/967: ifconfig and denial of service

[truman <truman@faith.suspicious.org>]

>Number:         967
>Category:       system
>Synopsis:       unpriviledged users can adjust interface options
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Nov  8 21:50:01 MST 1999
>Last-Modified:
>Originator:     truman
>Organization:
Suspicious dot Org
>Release:        
>Environment:
	
	System      : OpenBSD 2.6
	Architecture: OpenBSD.i386
	Machine     : i386
>Description:
Man page for ifconfig states "Only the super-user may modify the configuration
of a network interface. On both current and 2.5 systems I have been able to 
adjust the media options as an unpriviledged user. If you configure a media
option which is unsupported by your topology (ie. 100BaseTX using a 10baseT
hub), it can cause a denial of service to users using the altered interface.
>How-To-Repeat:
	
	faith:truman {109} id
	uid=1000(truman) gid=1000(truman) groups=1000(truman)

	faith:truman {110} /sbin/ifconfig -a
	fxp0: flags=8843
		media: Ethernet autoselect (10BaseT)
		status: active

	faith:truman {111} /sbin/ifconfig fxp0 media 100BaseTX
	
	faith:truman {112} /sbin/ifconfig -a
	fxp0: flags=8843
		media: Ethernet 100BaseTX
		status: no carrier

>Fix:
	

>Audit-Trail:
>Unformatted: