COMMAND
	    kernel
SYSTEMS AFFECTED
	    NetBSD 1.3.X,  NetBSD-current to  19990409, and  early versions of
	    NetBSD-1.4_ALPHA
PROBLEM
	    Following  is  based  on  NetBSD  Security Advisory.  Unprivileged
	    users can trigger a file-system locking error, causing the  system
	    to panic or hang.  The following command sequence will trigger the
	    vulnerability:
	
	        % ln -s ./ test
	        % ln -s ./ test
	
	    Certain  kernel  operations,  such  as  creating  a symbolic link,
	    request that the namei()  path name resolution routine  not unlock
	    the  node  of  the  directory  containing  the found file, instead
	    returning it  to the  caller locked.   When the  found file  is  a
	    symbolic link, this  parent must be  unlocked before the  symbolic
	    link is looked  up. This problem  results from the  test to unlock
	    the  parent  differing  from  the  test  to  lock the parent.  The
	    difference only manifests itself in the case of a path name  which
	    ends with a symbolic link ending with one or more "/"  characters.
	    NetBSD  1.3.3  and  prior  hang   when  this  bug  is   exercised.
	    NetBSD-current was  enhanced to  notice locking  problems and thus
	    panics instead of hanging.
	    The NetBSD Project  would like to  thank Antti Kantee  and Matthew
	    Orgass for providing information  about this problem, and  William
	    Studenmund for providing a solution.
SOLUTION
	    There are no workarounds for this problem.  A patched kernel  must
	    be installed to fix this problem.  A patch is available for NetBSD
	    1.3.3 which fixes this  problem.  You may  find this patch on  the
	    NetBSD ftp server:
	
	        ftp://ftp.NetBSD.ORG/pub/NetBSD/misc/security/patches/19990412-vfs_lookup
	
	    NetBSD-current  since  19990409  is  not  vulnerable.   Users   of
	    NetBSD-current should upgrade to a source tree later than 19990409