From 4ec66529e5d02cfe84b8c5a8c55ec9f88427e10f Mon Sep 17 00:00:00 2001 From: Stefan Metzmacher Date: Tue, 7 Dec 2010 16:10:49 +0100 Subject: [PATCH] s4:dsdb:password_hash: verify content if the BYPASS_PASSWORD_HASH control is used Make it much harder to import bad data into the password attributes. This isn't 100% safe, but much better than no checks. metze Autobuild-User: Stefan Metzmacher Autobuild-Date: Mon Dec 13 16:17:36 CET 2010 on sn-devel-104 --- .../dsdb/samdb/ldb_modules/password_hash.c | 397 +++++++++++++++++- 1 file changed, 395 insertions(+), 2 deletions(-) diff --git a/source4/dsdb/samdb/ldb_modules/password_hash.c b/source4/dsdb/samdb/ldb_modules/password_hash.c index 4e2e96fa6507..75df54be294e 100644 --- a/source4/dsdb/samdb/ldb_modules/password_hash.c +++ b/source4/dsdb/samdb/ldb_modules/password_hash.c @@ -151,6 +151,399 @@ struct setup_password_fields_io { } g; }; +static int password_hash_bypass(struct ldb_module *module, struct ldb_request *request) +{ + struct ldb_context *ldb = ldb_module_get_ctx(module); + const struct ldb_message *msg; + struct ldb_message_element *nte; + struct ldb_message_element *lme; + struct ldb_message_element *nthe; + struct ldb_message_element *lmhe; + struct ldb_message_element *sce; + + switch (request->operation) { + case LDB_ADD: + msg = request->op.add.message; + break; + case LDB_MODIFY: + msg = request->op.mod.message; + break; + default: + return ldb_next_request(module, request); + } + + /* nobody must touch password histories and 'supplementalCredentials' */ + nte = dsdb_get_single_valued_attr(msg, "unicodePwd", + request->operation); + lme = dsdb_get_single_valued_attr(msg, "dBCSPwd", + request->operation); + nthe = dsdb_get_single_valued_attr(msg, "ntPwdHistory", + request->operation); + lmhe = dsdb_get_single_valued_attr(msg, "lmPwdHistory", + request->operation); + sce = dsdb_get_single_valued_attr(msg, "supplementalCredentials", + request->operation); + +#define CHECK_HASH_ELEMENT(e, min, max) do {\ + if (e && e->num_values) { \ + unsigned int _count; \ + if (e->num_values != 1) { \ + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, \ + "num_values != 1"); \ + } \ + if ((e->values[0].length % 16) != 0) { \ + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, \ + "length % 16 != 0"); \ + } \ + _count = e->values[0].length / 16; \ + if (_count < min) { \ + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, \ + "count < min"); \ + } \ + if (_count > max) { \ + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, \ + "count > max"); \ + } \ + } \ +} while (0) + + CHECK_HASH_ELEMENT(nte, 1, 1); + CHECK_HASH_ELEMENT(lme, 1, 1); + CHECK_HASH_ELEMENT(nthe, 1, INT32_MAX); + CHECK_HASH_ELEMENT(lmhe, 1, INT32_MAX); + + if (sce && sce->num_values) { + enum ndr_err_code ndr_err; + struct supplementalCredentialsBlob *scb; + struct supplementalCredentialsPackage *scpp = NULL; + struct supplementalCredentialsPackage *scpk = NULL; + struct supplementalCredentialsPackage *scpkn = NULL; + struct supplementalCredentialsPackage *scpct = NULL; + DATA_BLOB scpbp = data_blob_null; + DATA_BLOB scpbk = data_blob_null; + DATA_BLOB scpbkn = data_blob_null; + DATA_BLOB scpbct = data_blob_null; + DATA_BLOB blob; + uint32_t i; + + if (sce->num_values != 1) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "num_values != 1"); + } + + scb = talloc_zero(request, struct supplementalCredentialsBlob); + if (!scb) { + return ldb_module_oom(module); + } + + ndr_err = ndr_pull_struct_blob_all(&sce->values[0], scb, scb, + (ndr_pull_flags_fn_t)ndr_pull_supplementalCredentialsBlob); + if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "ndr_pull_struct_blob_all"); + } + + if (scb->sub.num_packages < 2) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "num_packages < 2"); + } + + for (i=0; i < scb->sub.num_packages; i++) { + DATA_BLOB subblob; + + subblob = strhex_to_data_blob(scb, scb->sub.packages[i].data); + if (subblob.data == NULL) { + return ldb_module_oom(module); + } + + if (strcmp(scb->sub.packages[i].name, "Packages") == 0) { + if (scpp) { + return ldb_error(ldb, + LDB_ERR_CONSTRAINT_VIOLATION, + "Packages twice"); + } + scpp = &scb->sub.packages[i]; + scpbp = subblob; + continue; + } + if (strcmp(scb->sub.packages[i].name, "Primary:Kerberos") == 0) { + if (scpk) { + return ldb_error(ldb, + LDB_ERR_CONSTRAINT_VIOLATION, + "Primary:Kerberos twice"); + } + scpk = &scb->sub.packages[i]; + scpbk = subblob; + continue; + } + if (strcmp(scb->sub.packages[i].name, "Primary:Kerberos-Newer-Keys") == 0) { + if (scpkn) { + return ldb_error(ldb, + LDB_ERR_CONSTRAINT_VIOLATION, + "Primary:Kerberos-Newer-Keys twice"); + } + scpkn = &scb->sub.packages[i]; + scpbkn = subblob; + continue; + } + if (strcmp(scb->sub.packages[i].name, "Primary:CLEARTEXT") == 0) { + if (scpct) { + return ldb_error(ldb, + LDB_ERR_CONSTRAINT_VIOLATION, + "Primary:CLEARTEXT twice"); + } + scpct = &scb->sub.packages[i]; + scpbct = subblob; + continue; + } + + data_blob_free(&subblob); + } + + if (scpp) { + struct package_PackagesBlob *p; + uint32_t n; + + p = talloc_zero(scb, struct package_PackagesBlob); + if (p == NULL) { + return ldb_module_oom(module); + } + + ndr_err = ndr_pull_struct_blob(&scpbp, p, p, + (ndr_pull_flags_fn_t)ndr_pull_package_PackagesBlob); + if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "ndr_pull_struct_blob Packages"); + } + + if (p->names == NULL) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "Packages names == NULL"); + } + + for (n = 0; p->names[n]; n++) { + /* noop */ + } + + if (scb->sub.num_packages != (n + 1)) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "Packages num_packages != num_names + 1"); + } + + talloc_free(p); + } + + if (scpk) { + struct package_PrimaryKerberosBlob *k; + + k = talloc_zero(scb, struct package_PrimaryKerberosBlob); + if (k == NULL) { + return ldb_module_oom(module); + } + + ndr_err = ndr_pull_struct_blob(&scpbk, k, k, + (ndr_pull_flags_fn_t)ndr_pull_package_PrimaryKerberosBlob); + if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "ndr_pull_struct_blob PrimaryKerberos"); + } + + if (k->version != 3) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "PrimaryKerberos version != 3"); + } + + if (k->ctr.ctr3.salt.string == NULL) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "PrimaryKerberos salt == NULL"); + } + + if (strlen(k->ctr.ctr3.salt.string) == 0) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "PrimaryKerberos strlen(salt) == 0"); + } + + if (k->ctr.ctr3.num_keys != 2) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "PrimaryKerberos num_keys != 2"); + } + + if (k->ctr.ctr3.num_old_keys > k->ctr.ctr3.num_keys) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "PrimaryKerberos num_old_keys > num_keys"); + } + + if (k->ctr.ctr3.keys[0].keytype != ENCTYPE_DES_CBC_MD5) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "PrimaryKerberos key[0] != DES_CBC_MD5"); + } + if (k->ctr.ctr3.keys[1].keytype != ENCTYPE_DES_CBC_CRC) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "PrimaryKerberos key[1] != DES_CBC_CRC"); + } + + if (k->ctr.ctr3.keys[0].value_len != 8) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "PrimaryKerberos key[0] value_len != 8"); + } + if (k->ctr.ctr3.keys[1].value_len != 8) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "PrimaryKerberos key[1] value_len != 8"); + } + + for (i = 0; i < k->ctr.ctr3.num_old_keys; i++) { + if (k->ctr.ctr3.old_keys[i].keytype == + k->ctr.ctr3.keys[i].keytype && + k->ctr.ctr3.old_keys[i].value_len == + k->ctr.ctr3.keys[i].value_len) { + continue; + } + + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "PrimaryKerberos old_keys type/value_len doesn't match"); + } + + talloc_free(k); + } + + if (scpkn) { + struct package_PrimaryKerberosBlob *k; + + k = talloc_zero(scb, struct package_PrimaryKerberosBlob); + if (k == NULL) { + return ldb_module_oom(module); + } + + ndr_err = ndr_pull_struct_blob(&scpbkn, k, k, + (ndr_pull_flags_fn_t)ndr_pull_package_PrimaryKerberosBlob); + if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "ndr_pull_struct_blob PrimaryKerberosNeverKeys"); + } + + if (k->version != 4) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNerverKeys version != 4"); + } + + if (k->ctr.ctr4.salt.string == NULL) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNewerKeys salt == NULL"); + } + + if (strlen(k->ctr.ctr4.salt.string) == 0) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNewerKeys strlen(salt) == 0"); + } + + if (k->ctr.ctr4.num_keys != 4) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNewerKeys num_keys != 2"); + } + + if (k->ctr.ctr4.num_old_keys > k->ctr.ctr4.num_keys) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNewerKeys num_old_keys > num_keys"); + } + + if (k->ctr.ctr4.num_older_keys > k->ctr.ctr4.num_old_keys) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNewerKeys num_older_keys > num_old_keys"); + } + + if (k->ctr.ctr4.keys[0].keytype != ENCTYPE_AES256_CTS_HMAC_SHA1_96) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNewerKeys key[0] != AES256"); + } + if (k->ctr.ctr4.keys[1].keytype != ENCTYPE_AES128_CTS_HMAC_SHA1_96) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNewerKeys key[1] != AES128"); + } + if (k->ctr.ctr4.keys[2].keytype != ENCTYPE_DES_CBC_MD5) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNewerKeys key[2] != DES_CBC_MD5"); + } + if (k->ctr.ctr4.keys[3].keytype != ENCTYPE_DES_CBC_CRC) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNewerKeys key[3] != DES_CBC_CRC"); + } + + if (k->ctr.ctr4.keys[0].value_len != 32) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNewerKeys key[0] value_len != 32"); + } + if (k->ctr.ctr4.keys[1].value_len != 16) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNewerKeys key[1] value_len != 16"); + } + if (k->ctr.ctr4.keys[2].value_len != 8) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNewerKeys key[2] value_len != 8"); + } + if (k->ctr.ctr4.keys[3].value_len != 8) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "KerberosNewerKeys key[3] value_len != 8"); + } + + /* + * TODO: + * Maybe we can check old and older keys here. + * But we need to do some tests, if the old keys + * can be taken from the PrimaryKerberos blob + * (with only des keys), when the domain was upgraded + * from w2k3 to w2k8. + */ + + talloc_free(k); + } + + if (scpct) { + struct package_PrimaryCLEARTEXTBlob *ct; + + ct = talloc_zero(scb, struct package_PrimaryCLEARTEXTBlob); + if (ct == NULL) { + return ldb_module_oom(module); + } + + ndr_err = ndr_pull_struct_blob(&scpbct, ct, ct, + (ndr_pull_flags_fn_t)ndr_pull_package_PrimaryCLEARTEXTBlob); + if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "ndr_pull_struct_blob PrimaryCLEARTEXT"); + } + + if ((ct->cleartext.length % 2) != 0) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "PrimaryCLEARTEXT length % 2 != 0"); + } + + talloc_free(ct); + } + + ndr_err = ndr_push_struct_blob(&blob, scb, scb, + (ndr_push_flags_fn_t)ndr_push_supplementalCredentialsBlob); + if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "ndr_pull_struct_blob_all"); + } + + if (sce->values[0].length != blob.length) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "supplementalCredentialsBlob length differ"); + } + + if (memcmp(sce->values[0].data, blob.data, blob.length) != 0) { + return ldb_error(ldb, LDB_ERR_CONSTRAINT_VIOLATION, + "supplementalCredentialsBlob memcmp differ"); + } + + talloc_free(scb); + } + + ldb_debug(ldb, LDB_DEBUG_TRACE, "password_hash_bypass - validated\n"); + return ldb_next_request(module, request); +} + /* Get the NT hash, and fill it in as an entry in the password history, and specify it into io->g.nt_hash */ @@ -2322,7 +2715,7 @@ static int password_hash_add(struct ldb_module *module, struct ldb_request *req) /* Mark the "bypass" control as uncritical (done) */ bypass->critical = false; ldb_debug(ldb, LDB_DEBUG_TRACE, "password_hash_add (bypassing)\n"); - return ldb_next_request(module, req); + return password_hash_bypass(module, req); } /* nobody must touch password histories and 'supplementalCredentials' */ @@ -2521,7 +2914,7 @@ static int password_hash_modify(struct ldb_module *module, struct ldb_request *r /* Mark the "bypass" control as uncritical (done) */ bypass->critical = false; ldb_debug(ldb, LDB_DEBUG_TRACE, "password_hash_modify (bypassing)\n"); - return ldb_next_request(module, req); + return password_hash_bypass(module, req); } /* nobody must touch password histories and 'supplementalCredentials' */ -- 2.34.1