From 5f1aeeee089ccf20c4420281d386f28ea308faf1 Mon Sep 17 00:00:00 2001 From: Joseph Sutton Date: Wed, 27 Oct 2021 13:50:03 +1300 Subject: [PATCH] CVE-2020-25719 heimdal:kdc: Use sname from request rather than user-to-user TGT client name BUG: https://bugzilla.samba.org/show_bug.cgi?id=14873 Signed-off-by: Joseph Sutton Reviewed-by: Andrew Bartlett --- selftest/knownfail_heimdal_kdc | 20 ------ source4/heimdal/kdc/krb5tgs.c | 113 ++++++++++++++++----------------- 2 files changed, 55 insertions(+), 78 deletions(-) diff --git a/selftest/knownfail_heimdal_kdc b/selftest/knownfail_heimdal_kdc index 9cad1ca4d05..852a02d6d18 100644 --- a/selftest/knownfail_heimdal_kdc +++ b/selftest/knownfail_heimdal_kdc @@ -265,39 +265,19 @@ ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_tgs_authdata_no_pac ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_tgs_rodc_not_revealed ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_authdata_no_pac -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_matching_sname_host ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_no_pac -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_no_sname -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_non_existent_sname -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_other_sname -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_req ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_rodc_allowed_denied ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_rodc_denied ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_rodc_no_krbtgt_link ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_rodc_no_partial_secrets ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_rodc_not_allowed ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_rodc_not_revealed -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_rodc_revealed ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_rodc_sid_mismatch_existing ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_rodc_sid_mismatch_nonexisting ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_sid_mismatch_existing ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_sid_mismatch_nonexisting ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_tgt_cname_host -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_tgt_correct_cname -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_tgt_correct_realm -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_tgt_other_cname -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_tgt_wrong_realm ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_wrong_sname ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_wrong_sname_krbtgt -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_wrong_srealm ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_validate_authdata_no_pac ^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_validate_rodc_not_revealed -# -# PAC request tests -# -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_pac_request_false -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_pac_request_none -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_pac_request_true -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_user_pac_request_false -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_user_pac_request_none -^samba.tests.krb5.kdc_tgs_tests.samba.tests.krb5.kdc_tgs_tests.KdcTgsTests.test_user2user_user_pac_request_true diff --git a/source4/heimdal/kdc/krb5tgs.c b/source4/heimdal/kdc/krb5tgs.c index 9cad3ac7a76..d6ca1fe601c 100644 --- a/source4/heimdal/kdc/krb5tgs.c +++ b/source4/heimdal/kdc/krb5tgs.c @@ -1339,64 +1339,7 @@ tgs_build_reply(krb5_context context, if (b->kdc_options.canonicalize) flags |= HDB_F_CANON; - if(b->kdc_options.enc_tkt_in_skey){ - Ticket *t; - hdb_entry_ex *uu; - krb5_principal p; - Key *uukey; - krb5uint32 second_kvno = 0; - krb5uint32 *kvno_ptr = NULL; - - if(b->additional_tickets == NULL || - b->additional_tickets->len == 0){ - ret = KRB5KDC_ERR_BADOPTION; /* ? */ - kdc_log(context, config, 0, - "No second ticket present in request"); - goto out; - } - t = &b->additional_tickets->val[0]; - if(!get_krbtgt_realm(&t->sname)){ - kdc_log(context, config, 0, - "Additional ticket is not a ticket-granting ticket"); - ret = KRB5KDC_ERR_POLICY; - goto out; - } - ret = _krb5_principalname2krb5_principal(context, &p, t->sname, t->realm); - if (ret) { - goto out; - } - if(t->enc_part.kvno){ - second_kvno = *t->enc_part.kvno; - kvno_ptr = &second_kvno; - } - ret = _kdc_db_fetch(context, config, p, - HDB_F_GET_KRBTGT, kvno_ptr, - NULL, &uu); - krb5_free_principal(context, p); - if(ret){ - if (ret == HDB_ERR_NOENTRY) - ret = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN; - goto out; - } - ret = hdb_enctype2key(context, &uu->entry, - t->enc_part.etype, &uukey); - if(ret){ - _kdc_free_ent(context, uu); - ret = KRB5KDC_ERR_ETYPE_NOSUPP; /* XXX */ - goto out; - } - ret = krb5_decrypt_ticket(context, t, &uukey->key, &adtkt, 0); - _kdc_free_ent(context, uu); - if(ret) - goto out; - - ret = verify_flags(context, config, &adtkt, spn); - if (ret) - goto out; - - s = &adtkt.cname; - r = adtkt.crealm; - } else if (s == NULL) { + if (s == NULL) { ret = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN; krb5_set_error_message(context, ret, "No server in request"); goto out; @@ -1561,7 +1504,61 @@ server_lookup: krb5_enctype etype; if(b->kdc_options.enc_tkt_in_skey) { + Ticket *t; + hdb_entry_ex *uu; + krb5_principal p; + Key *uukey; + krb5uint32 second_kvno = 0; + krb5uint32 *kvno_ptr = NULL; size_t i; + + if(b->additional_tickets == NULL || + b->additional_tickets->len == 0){ + ret = KRB5KDC_ERR_BADOPTION; /* ? */ + kdc_log(context, config, 0, + "No second ticket present in request"); + goto out; + } + t = &b->additional_tickets->val[0]; + if(!get_krbtgt_realm(&t->sname)){ + kdc_log(context, config, 0, + "Additional ticket is not a ticket-granting ticket"); + ret = KRB5KDC_ERR_POLICY; + goto out; + } + ret = _krb5_principalname2krb5_principal(context, &p, t->sname, t->realm); + if (ret) { + goto out; + } + if(t->enc_part.kvno){ + second_kvno = *t->enc_part.kvno; + kvno_ptr = &second_kvno; + } + ret = _kdc_db_fetch(context, config, p, + HDB_F_GET_KRBTGT, kvno_ptr, + NULL, &uu); + krb5_free_principal(context, p); + if(ret){ + if (ret == HDB_ERR_NOENTRY) + ret = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN; + goto out; + } + ret = hdb_enctype2key(context, &uu->entry, + t->enc_part.etype, &uukey); + if(ret){ + _kdc_free_ent(context, uu); + ret = KRB5KDC_ERR_ETYPE_NOSUPP; /* XXX */ + goto out; + } + ret = krb5_decrypt_ticket(context, t, &uukey->key, &adtkt, 0); + _kdc_free_ent(context, uu); + if(ret) + goto out; + + ret = verify_flags(context, config, &adtkt, spn); + if (ret) + goto out; + ekey = &adtkt.key; for(i = 0; i < b->etype.len; i++) if (b->etype.val[i] == adtkt.key.keytype) -- 2.47.2