kern/74876: Can not receive Hop by Hop options

[dave baukus]

>Number:         74876
>Category:       kern
>Synopsis:       Can not receive Hop by Hop options
>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:   Wed Dec 08 23:50:23 GMT 2004
>Closed-Date:
>Last-Modified:
>Originator:     dave baukus
>Release:        4.10
>Organization:
Chiaro Networks
>Environment:
FreeBSD kavachi 4.10-RELEASE FreeBSD 4.10-RELEASE #0:  
Wed Dec  8 15:43:48 CST 2004dbaukus at krakatoa.chiaro.com:/home/dbaukus/kavachi-kern/compile/CHIAROS  i386
  
>Description:
It is impossible for an application receive an IPv6
Hop By Hop option via the RFC 2293 API; a bug in the kernel prevents
this.
>How-To-Repeat:
Write a program that sends and receives IPv6 packets using the
RFC 2292 API; enable the receiving socket to extract the Hop by Hop
ancillary data. The kernel will not append the Hop by Hop options to 
the socket() because of a bogus "privilege" check in ip6_savecontrol();
The check is bogus because it relies on curproc,  this function
is executed from ip6_input via ip6intr() from softclock.
curproc, if not NULL, almost certainly has no relationship to the destination socket.

>Fix:
Remove the "privileged" check from the IN6P_HOPOPTS delivery in 
ip6_savecontrol(); the setsockopt(...,IPV6_HOPOPTS,...) code
already checks suser() when the IN6P_HOPOPTS flag is set;
therefore, only a privileged socket will be able to receive these
options.

ip6_savecontrol () diff:

1372c1372
<       if ((in6p->in6p_flags & IN6P_HOPOPTS) != 0 && privileged) {
---
>       if ((in6p->in6p_flags & IN6P_HOPOPTS) != 0) {




>Release-Note:
>Audit-Trail:
>Unformatted: