From: Greg Hudson Date: Wed, 1 Dec 2010 20:01:46 +0000 (+0000) Subject: Implement restrict_anonymous_to_tgt realm flag X-Git-Tag: krb5-1.10-alpha1~639 X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=9479352bf9c570659ebdc40561ac81a7eb292b08;p=krb5.git Implement restrict_anonymous_to_tgt realm flag Implement a new realm flag to reject ticket requests from anonymous principals to any principal other than the local TGT. Allows FAST to be deployed using anonymous tickets as armor in realms where the set of authenticatable users must be constrained. ticket: 6829 target_version: 1.9 tags: pullup git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@24547 dc483132-0cff-0310-8789-dd5450dbe970 --- diff --git a/doc/admin.texinfo b/doc/admin.texinfo index 5dcc0d374..b6cc8e645 100644 --- a/doc/admin.texinfo +++ b/doc/admin.texinfo @@ -1562,7 +1562,11 @@ If you wish to change this (which we do not recommend, because the current implementation has little protection against denial-of-service attacks), the standard port number assigned for Kerberos TCP traffic is port 88. --@end table + +@itemx restrict_anonymous_to_kdc +This flag determines the default value of restrict_anonymous_to_kdc for +realms. The default value is @code{false}. +@end table @node realms (kdc.conf), pkinit kdc options, kdcdefaults, kdc.conf @subsection [realms] @@ -1742,6 +1746,15 @@ software on its application servers updated but another has not. This option defaults to @code{true}. +@itemx restrict_anonymous_to_tgt +A boolean value (@code{true}, @code{false}). If set to @code{true}, the +KDC will reject ticket requests from anonymous principals to service +principals other than the realm's ticket-granting service. This option +allows anonymous PKINIT to be enabled for use as FAST armor tickets +without allowing anonymous authentication to services. By default, the +value of restrict_anonymous_to_tgt as specified in the [kdcdefaults] +section is used. + @end table @node pkinit kdc options, Sample kdc.conf File, realms (kdc.conf), kdc.conf diff --git a/src/include/adm.h b/src/include/adm.h index 68f3c7a89..c23cd89e3 100644 --- a/src/include/adm.h +++ b/src/include/adm.h @@ -210,6 +210,7 @@ typedef struct __krb5_realm_params { krb5_flags realm_flags; krb5_key_salt_tuple *realm_keysalts; unsigned int realm_reject_bad_transit:1; + unsigned int realm_restrict_anon:1; unsigned int realm_kadmind_port_valid:1; unsigned int realm_enctype_valid:1; unsigned int realm_max_life_valid:1; @@ -217,6 +218,7 @@ typedef struct __krb5_realm_params { unsigned int realm_expiration_valid:1; unsigned int realm_flags_valid:1; unsigned int realm_reject_bad_transit_valid:1; + unsigned int realm_restrict_anon_valid:1; krb5_int32 realm_num_keysalts; } krb5_realm_params; #endif /* KRB5_ADM_H__ */ diff --git a/src/include/k5-int.h b/src/include/k5-int.h index 9a81d3bbc..ac46b4600 100644 --- a/src/include/k5-int.h +++ b/src/include/k5-int.h @@ -263,6 +263,7 @@ typedef INT64_TYPE krb5_int64; #define KRB5_CONF_REALM_TRY_DOMAINS "realm_try_domains" #define KRB5_CONF_REJECT_BAD_TRANSIT "reject_bad_transit" #define KRB5_CONF_RENEW_LIFETIME "renew_lifetime" +#define KRB5_CONF_RESTRICT_ANONYMOUS_TO_TGT "restrict_anonymous_to_tgt" #define KRB5_CONF_SAFE_CHECKSUM_TYPE "safe_checksum_type" #define KRB5_CONF_SUPPORTED_ENCTYPES "supported_enctypes" #define KRB5_CONF_TICKET_LIFETIME "ticket_lifetime" diff --git a/src/kdc/extern.h b/src/kdc/extern.h index 24bad20a5..236e5ccd9 100644 --- a/src/kdc/extern.h +++ b/src/kdc/extern.h @@ -74,6 +74,7 @@ typedef struct __kdc_realm_data { krb5_deltat realm_maxlife; /* Maximum ticket life for realm */ krb5_deltat realm_maxrlife; /* Maximum renewable life for realm */ krb5_boolean realm_reject_bad_transit; /* Accept unverifiable transited_realm ? */ + krb5_boolean realm_restrict_anon; /* Anon to local TGT only */ } kdc_realm_t; extern kdc_realm_t **kdc_realmlist; @@ -95,6 +96,7 @@ kdc_realm_t *find_realm_data (char *, krb5_ui_4); #define master_princ kdc_active_realm->realm_mprinc #define tgs_server kdc_active_realm->realm_tgsprinc #define reject_bad_transit kdc_active_realm->realm_reject_bad_transit +#define restrict_anon kdc_active_realm->realm_restrict_anon /* various externs for KDC */ extern krb5_data empty_string; /* an empty string */ diff --git a/src/kdc/kdc_util.c b/src/kdc/kdc_util.c index 691ece06c..62fea6fdb 100644 --- a/src/kdc/kdc_util.c +++ b/src/kdc/kdc_util.c @@ -838,6 +838,21 @@ errcode_to_protocol(krb5_error_code code) return (protcode >= 0 && protcode <= 128) ? protcode : KRB_ERR_GENERIC; } +/* Return -1 if the AS or TGS request is disallowed due to KDC policy on + * anonymous tickets. */ +static int +check_anon(krb5_context context, krb5_principal client, krb5_principal server) +{ + /* If restrict_anon is set, reject requests from anonymous to principals + * other than the local TGT. */ + if (restrict_anon && + krb5_principal_compare_any_realm(context, client, + krb5_anonymous_principal()) && + !krb5_principal_compare(context, server, tgs_server)) + return -1; + return 0; +} + /* * Routines that validate a AS request; checks a lot of things. :-) * @@ -957,6 +972,11 @@ validate_as_request(register krb5_kdc_req *request, krb5_db_entry client, return(KDC_ERR_MUST_USE_USER2USER); } + if (check_anon(kdc_context, request->client, request->server) != 0) { + *status = "ANONYMOUS NOT ALLOWED"; + return(KDC_ERR_POLICY); + } + /* Perform KDB module policy checks. */ ret = krb5_db_check_policy_as(kdc_context, request, &client, &server, kdc_time, status, e_data); @@ -1379,6 +1399,12 @@ validate_tgs_request(register krb5_kdc_req *request, krb5_db_entry server, return KRB_ERR_GENERIC; } + if (check_anon(kdc_context, ticket->enc_part2->client, + request->server) != 0) { + *status = "ANONYMOUS NOT ALLOWED"; + return(KDC_ERR_POLICY); + } + /* Perform KDB module policy checks. */ ret = krb5_db_check_policy_tgs(kdc_context, request, &server, ticket, status, e_data); diff --git a/src/kdc/main.c b/src/kdc/main.c index 5b90bd592..57cd226fb 100644 --- a/src/kdc/main.c +++ b/src/kdc/main.c @@ -279,8 +279,8 @@ handle_referral_params(krb5_realm_params *rparams, static krb5_error_code init_realm(kdc_realm_t *rdp, char *realm, char *def_mpname, krb5_enctype def_enctype, char *def_udp_ports, char *def_tcp_ports, - krb5_boolean def_manual, char **db_args, char *no_refrls, - char *host_based_srvcs) + krb5_boolean def_manual, krb5_boolean def_restrict_anon, + char **db_args, char *no_refrls, char *host_based_srvcs) { krb5_error_code kret; krb5_boolean manual; @@ -356,6 +356,11 @@ init_realm(kdc_realm_t *rdp, char *realm, char *def_mpname, } else manual = def_manual; + if (rparams && rparams->realm_restrict_anon_valid) + rdp->realm_restrict_anon = rparams->realm_restrict_anon; + else + rdp->realm_restrict_anon = def_restrict_anon; + /* Handle master key type */ if (rparams && rparams->realm_enctype_valid) rdp->realm_mkey.enctype = (krb5_enctype) rparams->realm_enctype; @@ -655,6 +660,7 @@ initialize_realms(krb5_context kcontext, int argc, char **argv) krb5_enctype menctype = ENCTYPE_UNKNOWN; kdc_realm_t *rdatap = NULL; krb5_boolean manual = FALSE; + krb5_boolean def_restrict_anon; char *default_udp_ports = 0; char *default_tcp_ports = 0; krb5_pointer aprof; @@ -678,6 +684,9 @@ initialize_realms(krb5_context kcontext, int argc, char **argv) hierarchy[1] = KRB5_CONF_MAX_DGRAM_REPLY_SIZE; if (krb5_aprof_get_int32(aprof, hierarchy, TRUE, &max_dgram_reply_size)) max_dgram_reply_size = MAX_DGRAM_SIZE; + hierarchy[1] = KRB5_CONF_RESTRICT_ANONYMOUS_TO_TGT; + if (krb5_aprof_get_boolean(aprof, hierarchy, TRUE, &def_restrict_anon)) + def_restrict_anon = FALSE; hierarchy[1] = KRB5_CONF_NO_HOST_REFERRAL; if (krb5_aprof_get_string_all(aprof, hierarchy, &no_refrls)) no_refrls = 0; @@ -736,7 +745,8 @@ initialize_realms(krb5_context kcontext, int argc, char **argv) if ((rdatap = (kdc_realm_t *) malloc(sizeof(kdc_realm_t)))) { if ((retval = init_realm(rdatap, optarg, mkey_name, menctype, default_udp_ports, - default_tcp_ports, manual, db_args, + default_tcp_ports, manual, + def_restrict_anon, db_args, no_refrls, host_based_srvcs))) { fprintf(stderr, "%s: cannot initialize realm %s - see log file for details\n", @@ -848,8 +858,8 @@ initialize_realms(krb5_context kcontext, int argc, char **argv) if ((rdatap = (kdc_realm_t *) malloc(sizeof(kdc_realm_t)))) { if ((retval = init_realm(rdatap, lrealm, mkey_name, menctype, default_udp_ports, default_tcp_ports, - manual, db_args, no_refrls, - host_based_srvcs))) { + manual, def_restrict_anon, db_args, + no_refrls, host_based_srvcs))) { fprintf(stderr,"%s: cannot initialize realm %s - see log file for details\n", argv[0], lrealm); exit(1); diff --git a/src/lib/kadm5/admin.h b/src/lib/kadm5/admin.h index 99837033b..8b59c6b5b 100644 --- a/src/lib/kadm5/admin.h +++ b/src/lib/kadm5/admin.h @@ -291,6 +291,7 @@ typedef struct __krb5_realm_params { krb5_flags realm_flags; krb5_key_salt_tuple *realm_keysalts; unsigned int realm_reject_bad_transit:1; + unsigned int realm_restrict_anon:1; unsigned int realm_kadmind_port_valid:1; unsigned int realm_enctype_valid:1; unsigned int realm_max_life_valid:1; @@ -298,6 +299,7 @@ typedef struct __krb5_realm_params { unsigned int realm_expiration_valid:1; unsigned int realm_flags_valid:1; unsigned int realm_reject_bad_transit_valid:1; + unsigned int realm_restrict_anon_valid:1; krb5_int32 realm_num_keysalts; } krb5_realm_params; diff --git a/src/lib/kadm5/alt_prof.c b/src/lib/kadm5/alt_prof.c index 6a7965512..cdd732113 100644 --- a/src/lib/kadm5/alt_prof.c +++ b/src/lib/kadm5/alt_prof.c @@ -1058,6 +1058,12 @@ krb5_read_realm_params(kcontext, realm, rparamp) rparams->realm_reject_bad_transit_valid = 1; } + hierarchy[2] = KRB5_CONF_RESTRICT_ANONYMOUS_TO_TGT; + if (!krb5_aprof_get_boolean(aprofile, hierarchy, TRUE, &bvalue)) { + rparams->realm_restrict_anon = bvalue; + rparams->realm_restrict_anon_valid = 1; + } + hierarchy[2] = KRB5_CONF_NO_HOST_REFERRAL; if (!krb5_aprof_get_string_all(aprofile, hierarchy, &no_refrls)) rparams->realm_no_host_referral = no_refrls; diff --git a/src/tests/t_anonpkinit.py b/src/tests/t_anonpkinit.py index 0149a671b..ddb96919b 100644 --- a/src/tests/t_anonpkinit.py +++ b/src/tests/t_anonpkinit.py @@ -25,10 +25,23 @@ pkinit_krb5_conf = { } } -realm = K5Realm(krb5_conf=pkinit_krb5_conf, create_user=False, - create_host=False) +restrictive_kdc_conf = { + 'all': { 'realms' : { '$realm' : { + 'restrict_anonymous_to_tgt' : 'true' } } } } + +# In the basic test, anonymous is not restricted, so kvno should succeed. +realm = K5Realm(krb5_conf=pkinit_krb5_conf, create_user=False) realm.addprinc('WELLKNOWN/ANONYMOUS') realm.kinit('@%s' % realm.realm, flags=['-n']) realm.klist('WELLKNOWN/ANONYMOUS@WELLKNOWN:ANONYMOUS') +realm.run_as_client([kvno, realm.host_princ]) +realm.stop() + +# Now try again with anonymous restricted; kvno should fail. +realm = K5Realm(krb5_conf=pkinit_krb5_conf, kdc_conf=restrictive_kdc_conf, + create_user=False) +realm.addprinc('WELLKNOWN/ANONYMOUS') +realm.kinit('@%s' % realm.realm, flags=['-n']) +realm.run_as_client([kvno, realm.host_princ], expected_code=1) success('Anonymous PKINIT.') diff --git a/src/util/k5test.py b/src/util/k5test.py index a710eee3a..a032d78b5 100644 --- a/src/util/k5test.py +++ b/src/util/k5test.py @@ -181,6 +181,7 @@ Scripts may use the following functions and variables: - ktutil - kinit - klist + - kvno - kdestroy - kpasswd - t_inetd @@ -1054,6 +1055,7 @@ kdb5_util = os.path.join(buildtop, 'kadmin', 'dbutil', 'kdb5_util') ktutil = os.path.join(buildtop, 'kadmin', 'ktutil', 'ktutil') kinit = os.path.join(buildtop, 'clients', 'kinit', 'kinit') klist = os.path.join(buildtop, 'clients', 'klist', 'klist') +kvno = os.path.join(buildtop, 'clients', 'kvno', 'kvno') kdestroy = os.path.join(buildtop, 'clients', 'kdestroy', 'kdestroy') kpasswd = os.path.join(buildtop, 'clients', 'kpasswd', 'kpasswd') t_inetd = os.path.join(buildtop, 'tests', 'dejagnu', 't_inetd')