diff options
Diffstat (limited to 'source4/heimdal/kdc/kerberos5.c')
| -rw-r--r-- | source4/heimdal/kdc/kerberos5.c | 236 |
1 files changed, 138 insertions, 98 deletions
diff --git a/source4/heimdal/kdc/kerberos5.c b/source4/heimdal/kdc/kerberos5.c index a437b9dbd9..4bc1619170 100644 --- a/source4/heimdal/kdc/kerberos5.c +++ b/source4/heimdal/kdc/kerberos5.c @@ -74,9 +74,9 @@ _kdc_find_padata(const KDC_REQ *req, int *start, int type) if (req->padata == NULL) return NULL; - while(*start < req->padata->len){ + while((size_t)*start < req->padata->len){ (*start)++; - if(req->padata->val[*start - 1].padata_type == type) + if(req->padata->val[*start - 1].padata_type == (unsigned)type) return &req->padata->val[*start - 1]; } return NULL; @@ -123,36 +123,103 @@ is_default_salt_p(const krb5_salt *default_salt, const Key *key) */ krb5_error_code -_kdc_find_etype(krb5_context context, const hdb_entry_ex *princ, +_kdc_find_etype(krb5_context context, krb5_boolean use_strongest_session_key, + krb5_boolean is_preauth, hdb_entry_ex *princ, krb5_enctype *etypes, unsigned len, - Key **ret_key) + krb5_enctype *ret_enctype, Key **ret_key) { - int i; - krb5_error_code ret = KRB5KDC_ERR_ETYPE_NOSUPP; + krb5_error_code ret; krb5_salt def_salt; + krb5_enctype enctype = ETYPE_NULL; + Key *key; + int i; - krb5_get_pw_salt (context, princ->entry.principal, &def_salt); + /* We'll want to avoid keys with v4 salted keys in the pre-auth case... */ + ret = krb5_get_pw_salt(context, princ->entry.principal, &def_salt); + if (ret) + return ret; - for(i = 0; ret != 0 && i < len ; i++) { - Key *key = NULL; + ret = KRB5KDC_ERR_ETYPE_NOSUPP; - if (krb5_enctype_valid(context, etypes[i]) != 0 && - !_kdc_is_weak_exception(princ->entry.principal, etypes[i])) - continue; + if (use_strongest_session_key) { + const krb5_enctype *p; + krb5_enctype clientbest = ETYPE_NULL; + int j; - while (hdb_next_enctype2key(context, &princ->entry, etypes[i], &key) == 0) { - if (key->key.keyvalue.length == 0) { - ret = KRB5KDC_ERR_NULL_KEY; + /* + * Pick the strongest key that the KDC, target service, and + * client all support, using the local cryptosystem enctype + * list in strongest-to-weakest order to drive the search. + * + * This is not what RFC4120 says to do, but it encourages + * adoption of stronger enctypes. This doesn't play well with + * clients that have multiple Kerberos client implementations + * available with different supported enctype lists. + */ + + /* drive the search with local supported enctypes list */ + p = krb5_kerberos_enctypes(context); + for (i = 0; p[i] != ETYPE_NULL && enctype == ETYPE_NULL; i++) { + if (krb5_enctype_valid(context, p[i]) != 0) continue; + + /* check that the client supports it too */ + for (j = 0; j < len && enctype == ETYPE_NULL; j++) { + if (p[i] != etypes[j]) + continue; + /* save best of union of { client, crypto system } */ + if (clientbest == ETYPE_NULL) + clientbest = p[i]; + /* check target princ support */ + ret = hdb_enctype2key(context, &princ->entry, p[i], &key); + if (ret) + continue; + if (is_preauth && !is_default_salt_p(&def_salt, key)) + continue; + enctype = p[i]; } - *ret_key = key; - ret = 0; - if (is_default_salt_p(&def_salt, key)) { - krb5_free_salt (context, def_salt); - return ret; + } + if (clientbest != ETYPE_NULL && enctype == ETYPE_NULL) + enctype = clientbest; + else if (enctype == ETYPE_NULL) + ret = KRB5KDC_ERR_ETYPE_NOSUPP; + if (ret == 0 && ret_enctype != NULL) + *ret_enctype = enctype; + if (ret == 0 && ret_key != NULL) + *ret_key = key; + } else { + /* + * Pick the first key from the client's enctype list that is + * supported by the cryptosystem and by the given principal. + * + * RFC4120 says we SHOULD pick the first _strong_ key from the + * client's list... not the first key... If the admin disallows + * weak enctypes in krb5.conf and selects this key selection + * algorithm, then we get exactly what RFC4120 says. + */ + for(key = NULL, i = 0; ret != 0 && i < len; i++, key = NULL) { + + if (krb5_enctype_valid(context, etypes[i]) != 0 && + !_kdc_is_weak_exception(princ->entry.principal, etypes[i])) + continue; + + while (hdb_next_enctype2key(context, &princ->entry, etypes[i], &key) == 0) { + if (key->key.keyvalue.length == 0) { + ret = KRB5KDC_ERR_NULL_KEY; + continue; + } + if (ret_key != NULL) + *ret_key = key; + if (ret_enctype != NULL) + *ret_enctype = etypes[i]; + ret = 0; + if (is_preauth && is_default_salt_p(&def_salt, key)) + goto out; } } } + +out: krb5_free_salt (context, def_salt); return ret; } @@ -211,8 +278,8 @@ log_patypes(krb5_context context, { struct rk_strpool *p = NULL; char *str; - int i; - + size_t i; + for (i = 0; i < padata->len; i++) { switch(padata->val[i].padata_type) { case KRB5_PADATA_PK_AS_REQ: @@ -240,7 +307,7 @@ log_patypes(krb5_context context, } if (p == NULL) p = rk_strpoolprintf(p, "none"); - + str = rk_strpoolcollect(p); kdc_log(context, config, 0, "Client sent patypes: %s", str); free(str); @@ -264,7 +331,7 @@ _kdc_encode_reply(krb5_context context, { unsigned char *buf; size_t buf_size; - size_t len; + size_t len = 0; krb5_error_code ret; krb5_crypto crypto; @@ -614,7 +681,7 @@ log_as_req(krb5_context context, krb5_error_code ret; struct rk_strpool *p; char *str; - int i; + size_t i; p = rk_strpoolprintf(NULL, "%s", "Client supported enctypes: "); @@ -694,13 +761,13 @@ kdc_check_flags(krb5_context context, "Client (%s) has invalid bit set", client_name); return KRB5KDC_ERR_POLICY; } - + if(!client->flags.client){ kdc_log(context, config, 0, "Principal may not act as client -- %s", client_name); return KRB5KDC_ERR_POLICY; } - + if (client->valid_start && *client->valid_start > kdc_time) { char starttime_str[100]; krb5_format_time(context, *client->valid_start, @@ -710,7 +777,7 @@ kdc_check_flags(krb5_context context, starttime_str, client_name); return KRB5KDC_ERR_CLIENT_NOTYET; } - + if (client->valid_end && *client->valid_end < kdc_time) { char endtime_str[100]; krb5_format_time(context, *client->valid_end, @@ -720,7 +787,7 @@ kdc_check_flags(krb5_context context, endtime_str, client_name); return KRB5KDC_ERR_NAME_EXP; } - + if (client->pw_end && *client->pw_end < kdc_time && (server_ex == NULL || !server_ex->entry.flags.change_pw)) { char pwend_str[100]; @@ -809,7 +876,7 @@ _kdc_check_addresses(krb5_context context, krb5_address addr; krb5_boolean result; krb5_boolean only_netbios = TRUE; - int i; + size_t i; if(config->check_ticket_addresses == 0) return TRUE; @@ -976,7 +1043,7 @@ _kdc_as_rep(krb5_context context, goto out; } } else if (b->kdc_options.request_anonymous) { - kdc_log(context, config, 0, + kdc_log(context, config, 0, "Request for a anonymous ticket with non " "anonymous client name: %s", client_name); ret = KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN; @@ -1018,59 +1085,31 @@ _kdc_as_rep(krb5_context context, memset(&ek, 0, sizeof(ek)); /* - * Select a session enctype from the list of the crypto systems - * supported enctype, is supported by the client and is one of the - * enctype of the enctype of the krbtgt. + * Select a session enctype from the list of the crypto system + * supported enctypes that is supported by the client and is one of + * the enctype of the enctype of the service (likely krbtgt). * - * The later is used as a hint what enctype all KDC are supporting - * to make sure a newer version of KDC wont generate a session - * enctype that and older version of a KDC in the same realm can't + * The latter is used as a hint of what enctypes all KDC support, + * to make sure a newer version of KDC won't generate a session + * enctype that an older version of a KDC in the same realm can't * decrypt. - * - * But if the KDC admin is paranoid and doesn't want to have "no + */ + ret = _kdc_find_etype(context, config->as_use_strongest_session_key, FALSE, + client, b->etype.val, b->etype.len, &sessionetype, + NULL); + if (ret) { + kdc_log(context, config, 0, + "Client (%s) from %s has no common enctypes with KDC " + "to use for the session key", + client_name, from); + goto out; + } + /* + * But if the KDC admin is paranoid and doesn't want to have "not * the best" enctypes on the krbtgt, lets save the best pick from * the client list and hope that that will work for any other * KDCs. */ - { - const krb5_enctype *p; - krb5_enctype clientbest = ETYPE_NULL; - int i, j; - - p = krb5_kerberos_enctypes(context); - - sessionetype = ETYPE_NULL; - - for (i = 0; p[i] != ETYPE_NULL && sessionetype == ETYPE_NULL; i++) { - if (krb5_enctype_valid(context, p[i]) != 0) - continue; - - for (j = 0; j < b->etype.len && sessionetype == ETYPE_NULL; j++) { - Key *dummy; - /* check with client */ - if (p[i] != b->etype.val[j]) - continue; - /* save best of union of { client, crypto system } */ - if (clientbest == ETYPE_NULL) - clientbest = p[i]; - /* check with krbtgt */ - ret = hdb_enctype2key(context, &server->entry, p[i], &dummy); - if (ret) - continue; - sessionetype = p[i]; - } - } - /* if krbtgt had no shared keys with client, pick clients best */ - if (clientbest != ETYPE_NULL && sessionetype == ETYPE_NULL) { - sessionetype = clientbest; - } else if (sessionetype == ETYPE_NULL) { - kdc_log(context, config, 0, - "Client (%s) from %s has no common enctypes with KDC" - "to use for the session key", - client_name, from); - goto out; - } - } /* * Pre-auth processing @@ -1111,7 +1150,7 @@ _kdc_as_rep(krb5_context context, ret = _kdc_pk_check_client(context, config, - clientdb, + clientdb, client, pkp, &client_cert); @@ -1119,7 +1158,7 @@ _kdc_as_rep(krb5_context context, e_text = "PKINIT certificate not allowed to " "impersonate principal"; _kdc_pk_free_client_param(context, pkp); - + kdc_log(context, config, 0, "%s", e_text); pkp = NULL; goto out; @@ -1148,9 +1187,9 @@ _kdc_as_rep(krb5_context context, EncryptedData enc_data; Key *pa_key; char *str; - + found_pa = 1; - + if (b->kdc_options.request_anonymous) { ret = KRB5KRB_AP_ERR_BAD_INTEGRITY; kdc_log(context, config, 0, "ENC-TS doesn't support anon"); @@ -1167,7 +1206,7 @@ _kdc_as_rep(krb5_context context, client_name); goto out; } - + ret = hdb_enctype2key(context, &client->entry, enc_data.etype, &pa_key); if(ret){ @@ -1256,7 +1295,7 @@ _kdc_as_rep(krb5_context context, free_PA_ENC_TS_ENC(&p); if (abs(kdc_time - p.patimestamp) > context->max_skew) { char client_time[100]; - + krb5_format_time(context, p.patimestamp, client_time, sizeof(client_time), TRUE); @@ -1353,8 +1392,9 @@ _kdc_as_rep(krb5_context context, /* * If there is a client key, send ETYPE_INFO{,2} */ - ret = _kdc_find_etype(context, client, b->etype.val, b->etype.len, - &ckey); + ret = _kdc_find_etype(context, + config->preauth_use_strongest_session_key, TRUE, + client, b->etype.val, b->etype.len, NULL, &ckey); if (ret == 0) { /* @@ -1384,7 +1424,7 @@ _kdc_as_rep(krb5_context context, goto out; } } - + ASN1_MALLOC_ENCODE(METHOD_DATA, buf, len, &method_data, &len, ret); free_METHOD_DATA(&method_data); @@ -1401,7 +1441,7 @@ _kdc_as_rep(krb5_context context, } if (clientdb->hdb_auth_status) - (clientdb->hdb_auth_status)(context, clientdb, client, + (clientdb->hdb_auth_status)(context, clientdb, client, HDB_AUTH_SUCCESS); /* @@ -1503,7 +1543,7 @@ _kdc_as_rep(krb5_context context, { time_t start; time_t t; - + start = et.authtime = kdc_time; if(f.postdated && req->req_body.from){ @@ -1663,8 +1703,8 @@ _kdc_as_rep(krb5_context context, PA_ClientCanonicalized canon; krb5_data data; PA_DATA pa; - krb5_crypto crypto; - size_t len; + krb5_crypto cryptox; + size_t len = 0; memset(&canon, 0, sizeof(canon)); @@ -1679,21 +1719,21 @@ _kdc_as_rep(krb5_context context, krb5_abortx(context, "internal asn.1 error"); /* sign using "returned session key" */ - ret = krb5_crypto_init(context, &et.key, 0, &crypto); + ret = krb5_crypto_init(context, &et.key, 0, &cryptox); if (ret) { free(data.data); goto out; } - ret = krb5_create_checksum(context, crypto, + ret = krb5_create_checksum(context, cryptox, KRB5_KU_CANONICALIZED_NAMES, 0, data.data, data.length, &canon.canon_checksum); free(data.data); - krb5_crypto_destroy(context, crypto); + krb5_crypto_destroy(context, cryptox); if (ret) goto out; - + ASN1_MALLOC_ENCODE(PA_ClientCanonicalized, data.data, data.length, &canon, &len, ret); free_Checksum(&canon.canon_checksum); @@ -1826,7 +1866,7 @@ _kdc_tkt_add_if_relevant_ad(krb5_context context, const krb5_data *data) { krb5_error_code ret; - size_t size; + size_t size = 0; if (tkt->authorization_data == NULL) { tkt->authorization_data = calloc(1, sizeof(*tkt->authorization_data)); @@ -1835,7 +1875,7 @@ _kdc_tkt_add_if_relevant_ad(krb5_context context, return ENOMEM; } } - + /* add the entry to the last element */ { AuthorizationData ad = { 0, NULL }; @@ -1863,7 +1903,7 @@ _kdc_tkt_add_if_relevant_ad(krb5_context context, } if (ade.ad_data.length != size) krb5_abortx(context, "internal asn.1 encoder error"); - + ret = add_AuthorizationData(tkt->authorization_data, &ade); der_free_octet_string(&ade.ad_data); if (ret) { |