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Date:      Tue, 15 May 2001 10:39:09 +0700
From:      Igor Podlesny <poige@morning.ru>
To:        Peter Pentchev <roam@orbitel.bg>
Cc:        freebsd-security@FreeBSD.ORG
Subject:   Re[2]: ipfw rules and securelevel
Message-ID:  <10967731793.20010515103909@morning.ru>
In-Reply-To: <20010514180201.C453@ringworld.oblivion.bg>
References:  <Pine.LNX.4.33.0105141802230.18115-100000@apsara.barc.ernet.in> <10320318256.20010514212856@morning.ru> <19322552168.20010514220610@morning.ru> <20010514170927.A849@ringworld.oblivion.bg> <5523460344.20010514222118@morning.ru> <20010514180201.C453@ringworld.oblivion.bg>

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> On Mon, May 14, 2001 at 10:21:18PM +0700, Igor Podlesny wrote:
>> 
>> 
>> > On Mon, May 14, 2001 at 10:06:10PM +0700, Igor Podlesny wrote:
>> >> 
>> >> >> Dear friends,
>> >> >>         Even in securelevel 3 I can bypass ipfw rules. In securelevel 3 I
>> >> >> as root can change the variable "net.inet.ip.fw.enable" using sysctl. When
>> >> >> I run a command
>> >> 
>> >> >>         sysctl -w net.inet.ip.fw.enable=0
>> >> 
>> >> >>         It disables the ipfw rules.
>> >> 
>> >> >> Is it a feature or hole in freebsd.
>> >> 
>> >> > doesn't matter how it is called, only matters how it hurts... (it does)
>> >> 
>> >> >> please help
>> >> 
>> >> the "patch" (hard to call it a patch, but nevertheless) is adding
>> >> CTLFLAG_SECURE to the relevant definition of the node:
>> >> 
>> >> this diff out is for 3.5 stable:
>> >> 
>> >> 92c92
>> >> < SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, enable, CTLFLAG_RW,                
>> >> ---                                                                        
>> >> > SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, enable, CTLFLAG_RW|CTLFLAG_SECURE, 
>> 
>> > Patches/diffs are usually much easier to review and apply if they are
>> > in context or unified diff format - this helps when the patch is made
>> > against a possibly changed file :)  And.. well.. it might be obvious
>> > to you (in this case it's pretty obvious to figure out ;), but still
>> > it helps a lot to mention which file(s) the patch is against :)
>> 
>> oh, you're right :)
>> 
>> it was
>> /usr/src/sys/netinet/ip_fw.c
>> 
>> unified diff:
>> 
>> --- /usr/src/sys/netinet/ip_fw.c.orig   Fri Mar 23 19:44:27 2001
>> +++ /usr/src/sys/netinet/ip_fw.c        Mon May 14 22:15:55 2001           
>> @@ -89,7 +89,7 @@                                                          
>>                                                                            
>>  #ifdef SYSCTL_NODE                                                        
>>  SYSCTL_NODE(_net_inet_ip, OID_AUTO, fw, CTLFLAG_RW, 0, "Firewall");       
>> -SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, enable, CTLFLAG_RW,                 
>> +SYSCTL_INT(_net_inet_ip_fw, OID_AUTO, enable, CTLFLAG_RW|CTLFLAG_SECURE,  
>>      &fw_enable, 0, "Enable ipfw");                                        
>>  SYSCTL_INT(_net_inet_ip_fw, OID_AUTO,one_pass,CTLFLAG_RW,                 
>>      &fw_one_pass, 0,                                                      

> Yup, this patch is much clearer, and I see no real reason against
> committing it.
My quick patch letter was for a person asking for help -- he asked and
I  tried to answer. I'm not a member of FreeBSD developer team, just a
user/amateur :)

>   Actually, I think that even more of those sysctl's
> should be flagged as 'secure' - e.g. the ones related to logging.

I  deem it is a business of the core team to decide what sysctls to be
protected  depending  on  the  securelevel value... cause it is theirs
design :)

-- 
 Igor                            mailto:poige@morning.ru



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