Tuesday Nov 02, 2010

MAC-then-encrypt - also harmful, also hard to do in Solaris

Researchers have discovered that MAC-then-encrypt in IPsec is harmful. Good thing you need to try REALLY HARD to be that dumb with Solaris.[Read More]

Tuesday Jan 05, 2010

IKEv2 project page updated

The IKEv2 project page on opensolaris.org now has links to both an early-revision design document, and a webrev pointer.

Wednesday Dec 02, 2009

OpenSolaris works out of the box with Amazon Virtual Private Cloud

Glenn Brunette asked me if OpenSolaris could access the Amazon Virtual Private Cloud or not. I told him it had better, or else there was a bug. He then did some scripting work, got some BGP help from Sowmini, and consulted Sebastien on some tunneling details. It's now up, running, and in a nice package, ready to use.

Monday Nov 30, 2009

IKEv2 project now on OpenSolaris

The IKEv2 project page is now available here on OpenSolaris. There's mailing-list information and a brief hello. We are working on design-level issues right now and some larval code, so c'mon over as we start to fire this up.

Friday May 29, 2009

New IPsec goodies in S10u7

There are a few new things in Solaris 10 Update 7 in the IPsec department.[Read More]

Tuesday Dec 09, 2008

How to tell when a performance project succeeds?

If your performance project exposes a dormant race condition, it's probably a success![Read More]

Friday Aug 15, 2008

Racoon2 on OpenSolaris - first tiny steps

Slowly but surely bringing up racoon2 on OpenSolaris.[Read More]

Tuesday Sep 04, 2007

Detangling IPsec NAT-Traversal, and a more stable API

Now any IPsec KM application can exploit NAT-Traversal.[Read More]

Monday Jul 16, 2007

Not using "ncp" on Niagara considered harmful

Make sure you are using the crypto accelerator in Niagara or IKE gets REALLY slow.[Read More]

Monday Oct 09, 2006

Tunnel Reform Code Review starts now.

Point those browsers and pull out the red pens, folks![Read More]

Thursday Jul 13, 2006

Tunnel Reform now open for your perusal

We're closing the last feature-hole in our IPsec...[Read More]

Tuesday Mar 07, 2006

ESP without authentication considered harmful

Hopefully you will read this and go "That's obvious". I'm writing this entry, however, for those who don't.

When IPsec was being specified over 10 years ago, attacks against cipher-block-chaining (CBC) encryption were understood. ESP has an authentication algorithm because AH had a vocal-enough opposition to merit having packet integrity in ESP also (there are also performance arguments for ESP-auth).

Now there actual attacks with actual results. Kenny Paterson and Arnold Yau have published a paper with attacks against no-authentication ESP Tunnel Mode. I believe some of the techniques can also be employed against Transport Mode as well, but again, only with no authentication present.

The simple solution, of course, is to employ your choice of ESP Authentication (encr_auth_algs in ipsecconf(1m) or ifconfig(1m)) or AH (auth_algs in ipsecconf(1m) or ifconfig(1m)) with your IPsec deployment. We warn users about such configurations with ifconfig(1m) today. There is an RFE to eliminate or make very difficult encryption-only configurations in Solaris. Maybe someone in the OpenSolaris community would like to take a stab at it? [EDITED to correct Kenny's last name.]

Thursday Dec 22, 2005

Also in Solaris 10 01/06 (aka. Update 1)

Solaris 10 Update 1 has shipped. There are nifty things like new-boot in there, but here's a small, subtle, but perhaps blog-worthy entry.

RFC 3947 NAT-Traversal is now part of Solaris. The RFCs were published literally days after the Solaris 10 development gate closed its doors for anything but critical bug fixes. We had used the draft-09 version of NAT-T for Solaris 10, but now we have the RFC-compliant one, which should insure maximum interoperability.

Not a big deal, but -savvy folks out there ought to know.

It's time to enjoy my Christmas/New-Year's break. Enjoy your own end-of-year activities (whatever they are) and catch you in 2006.

Tuesday Sep 13, 2005

Put IPsec to work in YOUR application

Hello coders!

Most people know that you can use ipsecconf(1m) to apply IPsec policy enforcement to an existing application. For example, if you wish to only allow inbound telnet traffic that's under IPsec protection, you'd put something like this into /etc/inet/ipsecinit.conf or other ipsecconf(1m) input:

# Inbound telnet traffic should be IPsec protected
{ lport 23 } ipsec { encr_algs any(128..) encr_auth_algs md5 sa shared}
             or ipsec { encr_algs any(128..) encr_auth_algs sha1 sa shared}

Combine that with appropriate IKE configuration or manual IPsec keys, and you can secure your telnet traffic against eavesdropping, connection hijacking, etc.

For existing services, using ipsecconf(1m) is the most expedient way to bring IPsec protection to bear on packets.

For new services, or services that are being modified anyway, consider using per-socket policy as an alternative. Some advantages to per-socket policy are:

  • Per-socket policy is stored internally in network session state (the conn_t structure in OpenSolaris). Entries from ipsecconf(1m) are stored in the global Security Policy Database (SPD). No global SPD entries means lower latency for fresh flow creation, and less lock acquisition.
  • Per-socket bypass means fewer bypass entries in global SPD. If I bypass remote-port 80 using ipsecconf(1m), I can, in theory, enter the system with a remote TCP packet with port=80. There's an RFE (6219908) to work around this, but per-socket is still quicker. I'd love a web proxy with the ability to set per-socket bypass.

The newly SMF-ized inetd(1m) would be a prime candidate for per-socket policy. See RFE 6226853, and this might be something someone in the OpenSolaris community would like to tackle!

Let's look at the ipsec_req_t structure that's been around since Solaris 8 in /usr/include/netinet/in.h:

/\*
 \* Different preferences that can be requested from IPSEC protocols.
 \*/
#define IP_SEC_OPT              0x22    /\* Used to set IPSEC options \*/
#define IPSEC_PREF_NEVER        0x01
#define IPSEC_PREF_REQUIRED     0x02
#define IPSEC_PREF_UNIQUE       0x04
/\*
 \* This can be used with the setsockopt() call to set per socket security
 \* options. When the application uses per-socket API, we will reflect
 \* the request on both outbound and inbound packets.
 \*/

typedef struct ipsec_req {
        uint_t          ipsr_ah_req;            /\* AH request \*/
        uint_t          ipsr_esp_req;           /\* ESP request \*/
        uint_t          ipsr_self_encap_req;    /\* Self-Encap request \*/
        uint8_t         ipsr_auth_alg;          /\* Auth algs for AH \*/
        uint8_t         ipsr_esp_alg;           /\* Encr algs for ESP \*/
        uint8_t         ipsr_esp_auth_alg;      /\* Auth algs for ESP \*/
} ipsec_req_t;
The ipsec_req_t is a subset of what one can specify with ipsecconf(1m) in Solaris 9 or later, but it matched what one could do with Solaris 8's version. Algorithm values are derived from PF_KEY (see /usr/include/net/pfkeyv2.h for values), as below. One could also use getipsecalgbyname(3nsl). If I wish to set a socket to use ESP with AES and and MD5, I'd set it up as follows:
        int s;  /\* Socket file descriptor... \*/
        ipsec_req_t ipsr;

        .....

        /\* NOTE: Do this BEFORE calling connect() or accept() for TCP sockets. \*/
        ipsr.ipsr_ah_req = 0;
        ipsr.ipsr_esp_req = IPSEC_PREF_REQUIRED;
        ipsr.ipsr_self_encap_req = 0;
        ipsr.ipsr_auth_alg = 0;
        ipsr.ipsr_esp_alg = SADB_EALG_AES;
        ipsr.ipsr_esp_auth_alg = SADB_AALG_MD5HMAC;
        if (setsockopt(s, IPPROTO_IP, IP_SEC_OPT, &ipsr, sizeof (ipsr)) == -1) {
                perror("setsockopt");
                bail();  /\* Ugggh, we failed. \*/
        }
        /\* You now have per-socket policy set. \*/
Notice I mentioned setting the socket option BEFORE calling connect() or accept? This is because of a phenomenon we implement called connection latching. Basically, connection latching means that once an endpoint is connect()-ed, the IPsec policy (whether set per-socket or inherited from the state of the global SPD at the time) latches in place. We made this decision to avoid keeping policy-per-datagram state for things like TCP retransmits.

One thing per-socket policy does not address is the case of unconnected datagram services. In a perfect world, we could have IPsec policy information percolate all the way to the socket layer, where an application can make fully-informed per-datagram decisions on whether or not a particular packet was secured or not. It's a hard problem, requiring XNET sockets (to use sendmsg() and recvmsg() with ancillary data).

BTW, if you want to bypass whatever global entries are in the SPD, you can zero out the structure, and set all three (ah, esp, self_encap) action indicators to IPSEC_PREF_NEVER. You need to be privileged (root or "sys_net_config") to use per-socket bypass, however.

So modulo the keying problem (setting up IKE or having both ends agree on IPsec manual keys), you can put IPsec to work right in your application. In fact, if you use IKE, you can let IKE sort out permissions and access control (by using PKI-issued certificates, self-signed certificates, or preshared keys) and have policy merely determine the details of the protection required.


EDITED: This entry brought to you by the Technorati tags , , and .

Wednesday Aug 31, 2005

Sooner than I thought!

Well, it looks like our friends on the OpenSolaris source team have been working more quickly than I thought. If you look at certain files (like the ESP source), they've been mysteriously fleshed-out. While crypto hasn't been sorted out, some other IPsec-specific files are now present in the tree!

Since crypto hasn't shown up yet, I guess we can't fully celebrate, but once it does, maybe Bill or I will have some more to say on the IPsec source.

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danmcd

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