kern/94599: [mac] MAC (Mandatory Access Control) and IPSEC can not coexist

[zhouyi zhou]

The following reply was made to PR kern/94599; it has been noted by GNATS.

From: zhouyi zhou <zhouyi04 at ios.cn>
To: bug-followup at FreeBSD.org
Cc:  
Subject: Re: kern/94599: [mac] MAC (Mandatory Access Control) and IPSEC can
 not coexist
Date: Tue, 28 Mar 2006 08:51:13 +0800

 I finally find reason why.
 
  there exists a serious bug in function ipsec_copypkt(m) 
 of netinet6/ipsec.c in FreeBSD 5.4, FreeBSD 6.0 and FreeBSD 7.0
 
 3469                                         MGETHDR(mnew, M_DONTWAIT, MT_HEADER);
 3470                                         if (mnew == NULL)
 3471                                                 goto fail;
 3472                                         mnew->m_pkthdr = n->m_pkthdr;
 3473 #if 0
 3474                                         /* XXX: convert to m_tag or delete? */
 3475                                         if (n->m_pkthdr.aux) {
 3476                                                 mnew->m_pkthdr.aux =
 3477                                                     m_copym(n->m_pkthdr.aux,
 3478                                                     0, M_COPYALL, M_DONTWAIT);
 3479                                         }
 3480 #endif
 3481                                         M_MOVE_PKTHDR(mnew, n);
 
 On line 3472, mnew->m_pkthdr is assigned n->m_pkthdr, and 
 on line 3481, in function m_move_pkthdr, mnew's tag list will be delete (and the n's tag 
 of cause). This will cause system to crash.
 
 After commenting out line 3472, everything is OK.
 
 
 Sincerely yours
 Zhouyi Zhou
 Institute of Software
 Chinese Academy of Sciences