MirOS Manual: isakmpd.policy(5)

ISAKMPD.POLICY(5)            BSD Reference Manual            ISAKMPD.POLICY(5)

NAME

     isakmpd.policy - policy configuration file for isakmpd

DESCRIPTION

     isakmpd.policy is the policy configuration file for the isakmpd(8) dae-
     mon, managing security association and key management for the ipsec(4)
     layer of the kernel's networking stack.

     The isakmpd(8) daemon (also known as IKE, for Internet Key Exchange) is
     used when two systems need to automatically set up a pair of Security As-
     sociations (SAs) for secure communication using IPsec. IKE operates in
     two stages:

     In the first stage (Main or Identity Protection Mode), the two IKE dae-
     mons establish a secure link between themselves, fully authenticating
     each other and establishing key material for encrypting/authenticating
     future communications between them. This step is typically only performed
     once for every pair of IKE daemons.

     In the second stage (also called Quick Mode), the two IKE daemons create
     the pair of SAs for the parties that wish to communicate using IPsec.
     These parties may be the hosts the IKE daemons run on, a host and a net-
     work behind a firewall, or two networks behind their respective
     firewalls. At this stage, the exact parameters of the SAs (e.g., algo-
     rithms to use, encapsulation mode, lifetime) and the identities of the
     communicating parties (hosts, networks, etc.) are specified. The reason
     for the existence of Quick Mode is to allow for fast SA setup, once the
     more heavy-weight Main Mode has been completed. Generally, Quick Mode
     uses the key material derived from Main Mode to provide keys to the IPsec
     transforms to be used.

     Alternatively, a new Diffie-Hellman computation may be performed, which
     significantly slows down the exchange, but at the same time provides Per-
     fect Forward Secrecy (PFS). Briefly, this means that even should an at-
     tacker manage to break long-term keys used in other sessions (or, specif-
     ically, if an attacker breaks the Diffie-Hellman exchange performed dur-
     ing Main Mode), they will not be able to decrypt this traffic. Normally,
     no PFS is provided (the key material used by the IPsec SAs established as
     a result of this exchange will be derived from the key material of the
     Main Mode exchange), allowing for a faster Quick Mode exchange (no public
     key computations).

     IKE proposals are "suggestions" by the initiator of an exchange to the
     responder as to what protocols and attributes should be used on a class
     of packets. For example, a given exchange may ask for ESP with 3DES and
     MD5 and AH with SHA1 (applied successively on the same packet), or just
     ESP with Blowfish and RIPEMD-160. The responder examines the proposals
     and determines which of them are acceptable, according to policy and any
     credentials.

     The following paragraphs assume some knowledge of the contents of the
     keynote(4) and keynote(5) man pages.

     In the KeyNote policy model for IPsec, no distinction is currently made
     based on the ordering of AH and ESP in the packet. Should this change in
     the future, an appropriate attribute (see below) will be added.

     The goal of security policy for IKE is thus to determine, based on local
     policy (provided in the isakmpd.policy file), credentials provided during
     the IKE exchanges (or obtained through other means), the SA attributes
     proposed during the exchange, and perhaps other (side-channel) informa-
     tion, whether a pair of SAs should be installed in the system (in fact,
     whether both the IPsec SAs and the flows should be installed). For each
     proposal suggested by or to the remote IKE daemon, the KeyNote system is
     consulted as to whether the proposal is acceptable based on local policy
     (contained in isakmpd.policy, in the form of policy assertions) and re-
     mote credentials (e.g., KeyNote credentials or X509 certificates provided
     by the remote IKE daemon).

     isakmpd.policy is simply a flat ascii(7) file containing KeyNote policy
     assertions, separated by blank lines (note that KeyNote assertions may
     not contain blank lines). isakmpd.policy is read when isakmpd(8) is first
     started, and every time it receives a SIGHUP signal. The new policies
     read will be used for all new Phase 2 (IPsec) SAs established from that
     point on (even if the associated Phase 1 SA was already established when
     the new policies were loaded). The policy change will not affect already
     established Phase 2 SAs.

     For more details on KeyNote assertion format, please see keynote(5).
     Briefly, KeyNote policy assertions used in IKE have the following charac-
     teristics:

     •   The Authorizer field is typically "POLICY" (but see the examples
         below, for use of policy delegation).

     •   The Licensees field can be an expression of passphrases used for au-
         thentication of the Main Mode exchanges, and/or public keys (typical-
         ly, X509 certificates), and/or X509 distinguished names.

     •   The Conditions field contains an expression of attributes from the
         IPsec policy action set (see below as well as the keynote syntax man
         page for more details).

     •   The ordered return-values set for IPsec policy is "false, true".

     For an explanation of these fields and their semantics, see keynote(5).

     For example, the following policy assertion:

         Authorizer: "POLICY"
         Licensees: "passphrase:foobar" || "x509-base64:abcd==" ||
           "passphrase-md5-hex:3858f62230ac3c915f300c664312c63f" ||
           "passphrase-sha1-hex:8843d7f92416211de9ebb963ff4ce28125932878"
         Conditions: app_domain == "IPsec policy" && esp_present == "yes"
                     && esp_enc_alg != "null" -> "true";

     says that any proposal from a remote host that authenticates using the
     passphrase "foobar" or the public key contained in the X509 certificate
     encoded as "abcd==" will be accepted, as long as it contains ESP with a
     non-null algorithm (i.e., the packet will be encrypted). The last two au-
     thorizers are the MD5 and SHA1 hashes respectively of the passphrase
     "foobar". This form may be used instead of the "passphrase:..." one to
     protect the passphrase as included in the policy file (or as distributed
     in a signed credential).

     The following policy assertion:

         Authorizer: "POLICY"
         Licensees: "DN:/CN=CA Certificate"
         Conditions: app_domain == "IPsec policy" && esp_present == "yes"
                     && esp_enc_alg != "null" -> "true";

     is similar to the previous one, but instead of including a complete X509
     credential in the Licensees field, only the X509 certificate's Subject
     Canonical Name needs to be specified (note that the "DN:" prefix is
     necessary).

     KeyNote credentials have the same format as policy assertions, with one
     difference: the Authorizer field always contains a public key, and the
     assertion is signed (and thus its integrity can be cryptographically ver-
     ified). Credentials are used to build chains of delegation of authority.
     They can be exchanged during an IKE exchange, or can be retrieved through
     some out-of-band mechanism (no such mechanism is currently supported in
     this implementation however). See isakmpd.conf(5) on how to specify what
     credentials to send in an IKE exchange.

     Passphrases that appear in the Licensees field are encoded as the string
     "passphrase:", followed by the passphrase itself (case-sensitive). Alter-
     natively (and preferably), they may be encoded using the "passphrase-
     md5-hex:" or "passphrase-sha1-hex:" prefixes, followed by the md5(1) or
     sha1(1) hash of the passphrase itself, encoded as a hexadecimal string
     (using lower-case letters only).

     When X509-based authentication is performed in Main Mode, any X509 certi-
     ficates received from the remote IKE daemon are converted to very simple
     KeyNote credentials. The conversion is straightforward: the issuer of the
     X509 certificate becomes the Authorizer of the KeyNote credential, the
     subject becomes the only Licensees entry, while the Conditions field sim-
     ply asserts that the credential is only valid for "IPsec policy" use (see
     the app_domain action attribute below).

     Similarly, any X509 CA certificates present in the directory pointed to
     by the appropriate isakmpd.conf(5) entry are converted to such pseudo-
     credentials. This allows one to write KeyNote policies that delegate
     specific authority to CAs (and the keys those CAs certify, recursively).

     For more details on KeyNote assertion format, see keynote(5).

     Information about the proposals, the identity of the remote IKE daemon,
     the packet classes to be protected, etc. are encoded in what is called an
     action set. The action set is composed of name-value attributes, similar
     in some ways to shell environment variables. These values are initialized
     by isakmpd(8) before each query to the KeyNote system, and can be tested
     against in the Conditions field of assertions. See keynote(4) and
     keynote(5) for more details on the format and semantics of the Conditions
     field.

     Note that assertions and credentials can make references to non-existent
     attributes without catastrophic failures (access may be denied, depending
     on the overall structure, but will not be accidentally granted). One rea-
     son for credentials referencing non-existent attributes is that they were
     defined within a specific implementation or network only.

     In the following attribute set, IPv4 addresses are encoded as ASCII
     strings in the usual dotted-quad format. However, all quads are three di-
     gits long. For example, the IPv4 address 10.128.1.12 would be encoded as
     010.128.001.012. Similarly, IPv6 addresses are encoded in the standard
     x:x:x:x:x:x:x:x format, where the 'x's are the hexadecimal values of the
     eight 16-bit pieces of the address. All 'x's are four digits long. For
     example, the address 1080:0:12:0:8:800:200C:417A would be encoded as
     1080:0000:0012:0000:0008:0800:200C:417A.

     The following attributes are currently defined:

     ah_auth_alg
              One of hmac-md5, hmac-sha, des-mac, kpdk, hmac-sha2-256, hmac-
              sha2-384, hmac-sha2-512, or hmac-ripemd. based on the authenti-
              cation method specified in the AH proposal.

     ah_ecn, esp_ecn, comp_ecn
              Set to yes or no, based on whether ECN was requested for the IP-
              sec tunnel.

     ah_encapsulation, esp_encapsulation, comp_encapsulation
              Set to tunnel or transport, based on the AH, ESP, and compres-
              sion proposal.

     ah_group_desc, esp_group_desc, comp_group_desc
              The Diffie-Hellman group identifier from the AH, ESP, and
              compression proposal, used for PFS during Quick Mode (see the
              pfs attribute above). If more than one of these attributes are
              set to a value other than zero, they should have the same value
              (in valid IKE proposals). Valid values are 1 (768-bit MODP), 2
              (1024-bit MODP), 3 (155-bit EC), 4 (185-bit EC), and 5 (1536-bit
              MODP).

     ah_hash_alg
              One of md5, sha, ripemd, sha2-256, sha2-384, sha2-512, or des,
              based on the hash algorithm specified in the AH proposal. This
              attribute describes the generic transform to be used in the AH
              authentication.

     ah_key_length, esp_key_length
              The number of key bits to be used by the authentication and en-
              cryption algorithms respectively (for variable key-size algo-
              rithms).

     ah_key_rounds, esp_key length
              The number of rounds of the authentication and encryption algo-
              rithms respectively (for variable round algorithms).

     ah_life_kbytes, esp_life_kbytes, comp_life_kbytes
              Set to the lifetime of the AH, ESP, and compression proposal, in
              kbytes of traffic. If no lifetime was proposed for the
              corresponding protocol (e.g., there was no proposal for AH), the
              corresponding attribute will be set to zero.

     ah_life_seconds, esp_life_seconds, comp_life_seconds
              Set to the lifetime of the AH, ESP, and compression proposal, in
              seconds. If no lifetime was proposed for the corresponding pro-
              tocol (e.g., there was no proposal for AH), the corresponding
              attribute will be set to zero.

     ah_present, esp_present, comp_present
              Set to yes if an AH, ESP, or compression proposal was received
              respectively, no otherwise.

     app_domain
              Always set to IPsec policy.

     comp_alg
              One of oui, deflate, lzs, or v42bis, based on the compression
              algorithm specified in the compression proposal.

     comp_dict_size
              Specifies the log2 maximum size of the dictionary, according to
              the compression proposal.

     comp_private_alg
              Set to an integer specifying the private algorithm in use, ac-
              cording to the compression proposal.

     doi      Always set to ipsec.

     esp_auth_alg
              One of hmac-md5, hmac-sha, des-mac, kpdk, hmac-sha2-256, hmac-
              sha2-384, hmac-sha2-512, or hmac-ripemd based on the authentica-
              tion method specified in the ESP proposal.

     esp_enc_alg
              One of des, des-iv64, 3des, rc4, idea, cast, blowfish, 3idea,
              des-iv32, rc4, null, or aes, based on the encryption algorithm
              specified in the ESP proposal.

     GMTTimeOfDay
              Set to the UTC date/time, in YYYYMMDDHHmmSS format.

     initiator
              Set to yes if the local daemon is initiating the Phase 2 SA, no
              otherwise.

     local_negotiation_address
              Set to the IPv4 or IPv6 address of the local interface used by
              the local IKE daemon for this exchange.

     LocalTimeOfDay
              Set to the local date/time, in YYYYMMDDHHmmSS format.

     pfs      Set to yes if a Diffie-Hellman exchange will be performed during
              this Quick Mode, no otherwise.

     phase_1  Set to aggressive if aggressive mode was used to establish the
              Phase 1 SA, or main if main mode was used instead.

     phase1_group_desc
              The Diffie-Hellman group identifier used in IKE Phase 1. Takes
              the same values as ah_group_desc.

     remote_filter, local_filter, remote_id
              When the corresponding filter_type specifies an address range or
              subnet, these are set to the upper and lower part of the address
              space separated by a dash ('-') character (if the type specifies
              a single address, they are set to that address).

              For FQDN and User FQDN types, these are set to the respective
              string. For Key ID, these are set to the hexadecimal representa-
              tion of the associated byte string (lower-case letters used) if
              the Key ID payload contains non-printable characters. Otherwise,
              they are set to the respective string.

              For ASN1 DN, these are set to the text encoding of the Dis-
              tinguished Name in the payload sent or received. The format is
              the same as that used in the Licensees field.

     remote_filter_addr_lower, local_filter_addr_lower, remote_id_addr_lower
              When the corresponding filter_type is IPv4 address or IPv6
              address, these contain the respective address. For IPv4 range or
              IPv6 range, these contain the lower end of the address range.
              For IPv4 subnet or IPv6 subnet, these contain the lowest address
              in the specified subnet.

     remote_filter_addr_upper, local_filter_addr_upper, remote_id_addr_upper
              When the corresponding filter_type is IPv4 address or IPv6
              address, these contain the respective address. For IPv4 range or
              IPv6 range, they contain the upper end of the address range. For
              IPv4 subnet or IPv6 subnet, they contain the highest address in
              the specified subnet.

     remote_filter_port, local_filter_port, remote_id_port
              Set to the transport protocol port.

     remote_filter_proto, local_filter_proto, remote_id_proto
              Set to etherip, tcp, udp, or the transport protocol number,
              depending on the transport protocol set in the IDci, IDcr, and
              Main Mode peer ID respectively.

     remote_filter_type, local_filter_type, remote_id_type
              Set to IPv4 address, IPv4 range, IPv4 subnet, IPv6 address, IPv6
              range, IPv6 subnet, FQDN, User FQDN, ASN1 DN, ASN1 GN, or Key
              ID, based on the Quick Mode Initiator ID, Quick Mode Responder
              ID, and Main Mode peer ID respectively.

     remote_negotiation_address
              Set to the IPv4 or IPv6 address of the remote IKE daemon.

FILES

     /etc/isakmpd/isakmpd.policy  The default isakmpd(8) policy configuration
                                  file.

     /usr/share/ipsec/isakmpd/policy
                                  A sample isakmpd(8) policy configuration
                                  file.

EXAMPLES

         Authorizer: "POLICY"
         Comment: This bare-bones assertion accepts everything

         Authorizer: "POLICY"
         Licensees: "passphrase-md5-hex:10838982612aff543e2e62a67c786550"
         Comment: This policy accepts anyone using shared-secret
                  authentication using the password mekmitasisgoat,
                  and does ESP with some form of encryption (not null).
         Conditions: app_domain == "IPsec policy" &&
                     esp_present == "yes" &&
                     esp_enc_alg != "null" -> "true";

         Authorizer: "POLICY"
         Licensees: "subpolicy1" || "subpolicy2"
         Comment: Delegate to two other sub-policies, so we
                  can manage our policy better. Since these subpolicies
                  are not "owned" by a key (and are thus unsigned), they
                  have to be in isakmpd.policy.
         Conditions: app_domain == "IPsec policy";

         KeyNote-Version: 2
         Licensees: "passphrase-md5-hex:9c42a1346e333a770904b2a2b37fa7d3"
         Conditions: esp_present == "yes" -> "true";
         Authorizer: "subpolicy1"

         Conditions: ah_present == "yes" ->
                        {
                            ah_auth_alg == "md5" -> "true";
                            ah_auth_alg == "sha" &&
                            esp_present == "no" -> "true";
                        };
         Licensees: "passphrase:otherpassword" ||
            "passphrase-sha1-hex:f5ed6e4abd30c36a89409b5da7ecb542c9fbf00f"
         Authorizer: "subpolicy2"

         keynote-version: 2
         comment: this is an example of a policy delegating to a CN.
         authorizer: "POLICY"
         licensees: "DN:/CN=CA Certificate/emailAddress=ca@foo.bar.com"

         keynote-version: 2
         comment: This is an example of a policy delegating to a key.
         authorizer: "POLICY"
         licensees: "x509-base64:MIICGDCCAYGgAwIBAgIBADANBgkqhkiG9w0BAQQ\
                     FADBSMQswCQYDVQQGEwJHQjEOMAwGA1UEChMFQmVuQ28xETAPBg\
                     NVBAMTCEJlbkNvIENBMSAwHgYJKoZIhvcNAQkBFhFiZW5AYWxnc\
                     m91cC5jby51azAeFw05OTEwMTEyMjQ5MzhaFw05OTExMTAyMjQ5\
                     MzhaMFIxCzAJBgNVBAYTAkdCMQ4wDAYDVQQKEwVCZW5DbzERMA8\
                     GA1UEAxMIQmVuQ28gQ0ExIDAeBgkqhkiG9w0BCQEWEWJlbkBhbG\
                     dyb3VwLmNvLnVrMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBg\
                     QCxyAte2HEVouXg1Yu+vDihbnjDRn+6k00Rv6cZqbwA3BQ30mC/\
                     3TFJ09VGXCaM0UKfpnxIpkBYLmOA3FWkKI0RvPU7E1AhKkhC1Ds\
                     PSBFjYHrB15T5lYzgfwKJCIxTDzZDx2iobUgPa0FRNGVUjpQ4/k\
                     MJ2BF4Wh7zY3X08rMzsQIDAQABMA0GCSqGSIb3DQEBBAUAA4GBA\
                     DWJ5pbTcE7iKHWLQTMYiz8i9jGi5+Eo1yr1Bab90tgaGQV0zrRH\
                     jDHgAAy1h8WSXuyQrXfgbx2rnWFPhx9CfmuAXn7sZmQE3mnUqeP\
                     ZL2dW87jdBGqtoUdNcoz5zKBkC943yasNui/O01MiqgadTThTJH\
                     d1Pn17LbJC1ZVRNjR5"
         conditions: app_domain == "IPsec policy" && doi == "ipsec" &&
                 pfs == "yes" && esp_present == "yes" && ah_present == "no" &&
                 (esp_enc_alg == "3des" || esp_enc_alg == "aes") -> "true";

         keynote-version: 2
         comment: This is an example of a credential, the signature does
                  not really verify (although the keys are real).
         licensees: "x509-base64:MIICGDCCAYGgAwIBAgIBADANBgkqhkiG9w0BAQQ\
                     FADBSMQswCQYDVQQGEwJHQjEOMAwGA1UEChMFQmVuQ28xETAPBg\
                     NVBAMTCEJlbkNvIENBMSAwHgYJKoZIhvcNAQkBFhFiZW5AYWxnc\
                     m91cC5jby51azAeFw05OTEwMTEyMzA2MjJaFw05OTExMTAyMzA2\
                     MjJaMFIxCzAJBgNVBAYTAkdCMQ4wDAYDVQQKEwVCZW5DbzERMA8\
                     GA1UEAxMIQmVuQ28gQ0ExIDAeBgkqhkiG9w0BCQEWEWJlbkBhbG\
                     dyb3VwLmNvLnVrMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBg\
                     QDaCs+JAB6YRKAVkoi1NkOpE1V3syApjBj0Ahjq5HqYAACo1JhM\
                     +QsPwuSWCNhBT51HX6G6UzfY3mOUz/vou6MJ/wor8EdeTX4nucx\
                     NSz/r6XI262aXezAp+GdBviuJZx3Q67ON/IWYrB4QtvihI4bMn5\
                     E55nF6TKtUMJTdATvs/wIDAQABMA0GCSqGSIb3DQEBBAUAA4GBA\
                     MaQOSkaiR8id0h6Zo0VSB4HpBnjpWqz1jNG8N4RPN0W8muRA2b9\
                     85GNP1bkC3fK1ZPpFTB0A76lLn11CfhAf/gV1iz3ELlUHo5J8nx\
                     Pu6XfsGJm3HsXJOuvOog8Aean4ODo4KInuAsnbLzpGl0d+Jqa5u\
                     TZUxsyg4QOBwYEU92H"
         authorizer: "x509-base64:MIICGDCCAYGgAwIBAgIBADANBgkqhkiG9w0BAQQ\
                      FADBSMQswCQYDVQQGEwJHQjEOMAwGA1UEChMFQmVuQ28xETAPBg\
                      NVBAMTCEJlbkNvIENBMSAwHgYJKoZIhvcNAQkBFhFiZW5AYWxnc\
                      m91cC5jby51azAeFw05OTEwMTEyMjQ5MzhaFw05OTExMTAyMjQ5\
                      MzhaMFIxCzAJBgNVBAYTAkdCMQ4wDAYDVQQKEwVCZW5DbzERMA8\
                      GA1UEAxMIQmVuQ28gQ0ExIDAeBgkqhkiG9w0BCQEWEWJlbkBhbG\
                      dyb3VwLmNvLnVrMIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBg\
                      QCxyAte2HEVouXg1Yu+vDihbnjDRn+6k00Rv6cZqbwA3BQ30mC/\
                      3TFJ09VGXCaM0UKfpnxIpkBYLmOA3FWkKI0RvPU7E1AhKkhC1Ds\
                      PSBFjYHrB15T5lYzgfwKJCIxTDzZDx2iobUgPa0FRNGVUjpQ4/k\
                      MJ2BF4Wh7zY3X08rMzsQIDAQABMA0GCSqGSIb3DQEBBAUAA4GBA\
                      DWJ5pbTcE7iKHWLQTMYiz8i9jGi5+Eo1yr1Bab90tgaGQV0zrRH\
                      jDHgAAy1h8WSXuyQrXfgbx2rnWFPhx9CfmuAXn7sZmQE3mnUqeP\
                      ZL2dW87jdBGqtoUdNcoz5zKBkC943yasNui/O01MiqgadTThTJH\
                      d1Pn17LbJC1ZVRNjR5"
     conditions: app_domain == "IPsec policy" && doi == "ipsec" &&
                 pfs == "yes" && esp_present == "yes" && ah_present == "no" &&
                 (esp_enc_alg == "3des" || esp_enc_alg == "aes") -> "true";
     Signature: "sig-x509-sha1-base64:ql+vrUxv14DcBOQHR2jsbXayq6T\
                 mmtMiUB745a8rjwSrQwh+KIVDlUrghPnqhSIkWSDi9oWWMbfg\
                 mkdudZ0wjgeTLMI2NI4GibMMsToakOKMex/0q4cpdpln3DKcQ\
                 IcjzRv4khDws69FT3QfELjcpShvbLrXmh1Z00OFmxjyqDw="

SEE ALSO

     ipsec(4), keynote(4), keynote(5), isakmpd(8)

BUGS

     A more sane way of expressing IPv6 address ranges is needed.

MirOS BSD #10-current           June 15, 2002                                7

Generated on 2014-07-04 21:17:45 by $MirOS: src/scripts/roff2htm,v 1.79 2014/02/10 00:36:11 tg Exp $

These manual pages and other documentation are copyrighted by their respective writers; their source is available at our CVSweb, AnonCVS, and other mirrors. The rest is Copyright © 2002‒2014 The MirOS Project, Germany.
This product includes material provided by Thorsten Glaser.

This manual page’s HTML representation is supposed to be valid XHTML/1.1; if not, please send a bug report – diffs preferred.