>Number:         5892
>Category:       kern
>Synopsis:       sbcratecontrol() is not compatible with CMSG_LEN() in some architecture
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people (Kernel Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Aug  1 02:20:01 1998
>Last-Modified:
>Originator:     Jun-ichiro itojun Itoh
>Organization:
	itojun.org
>Release:        NetBSD 1.3 and NetBSD 1.3.2
>Environment:
	
System: NetBSD hoge.kame.net 1.3 NetBSD 1.3 (HOGE.v6) #1: Sat Aug 1 08:01:15 PDT 1998 itojun@hoge:/usr/home/itojun/hyd/sys/arch/i386/compile/HOGE.v6 i386


>Description:
	sbcreatecontrol() and CMSG_LEN() assumes different thing in
	computing the size to be passed into cmsg_len.

	sbcreatecontrol() puts sizeof(struct cmsghdr) + x into cmsg_len().
	CMSG_LEN computes it by ALIGN(sizeof(struct cmsghdr)) + x.
	Due to the difference, CMSG_LEN(sizeof(int)) returns 20 in
	NetBSD/sparc.  However, sbcreatecontrol() sets 16 into cmsg_len.

	This problem appears in architectures which has ALIGN() aligns
	structure into 8 bytes (such as Sun sparc port).

	Confirmed in NetBSD 1.3.  NetBSD 1.3.2 seems to have the same problem
	(after looking into the source code).
>How-To-Repeat:
>Fix:
	change sbcreatecontrol(), or CMSG_LEN(), or ALIGN().
	I dunno which is the best way.
>Audit-Trail:
>Unformatted: