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authorStefan Metzmacher <metze@samba.org>2010-12-07 16:10:49 +0100
committerStefan Metzmacher <metze@samba.org>2010-12-13 16:17:36 +0100
commit4ec66529e5d02cfe84b8c5a8c55ec9f88427e10f (patch)
tree96cdd234fd3974ff3b778c32ee1cbf987f073429
parenta762e9cab70f3ecc000b5dd20ce5f792963e8a52 (diff)
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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 <metze@samba.org> Autobuild-Date: Mon Dec 13 16:17:36 CET 2010 on sn-devel-104
-rw-r--r--source4/dsdb/samdb/ldb_modules/password_hash.c397
1 files 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 4e2e96fa65..75df54be29 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' */