Merge tag 'samba-4.5.16' into v4-5-test

samba: tag release samba-4.5.16

8 files changed, 320 insertions, 25 deletions

diff --git a/WHATSNEW.txt b/WHATSNEW.txt
index b245e30a6f9..a204a5482e6 100644
--- a/WHATSNEW.txt
+++ b/WHATSNEW.txt
@@ -1,4 +1,80 @@
                    ==============================
+                   Release Notes for Samba 4.5.16
+                           March 13, 2018
+                   ==============================
+
+
+This is a security release in order to address the following defects:
+
+o  CVE-2018-1050 (Denial of Service Attack on external print server.)
+o  CVE-2018-1057 (Authenticated users can change other users' password.)
+
+
+=======
+Details
+=======
+
+o  CVE-2018-1050:
+   All versions of Samba from 4.0.0 onwards are vulnerable to a denial of
+   service attack when the RPC spoolss service is configured to be run as
+   an external daemon. Missing input sanitization checks on some of the
+   input parameters to spoolss RPC calls could cause the print spooler
+   service to crash.
+
+   There is no known vulnerability associated with this error, merely a
+   denial of service. If the RPC spoolss service is left by default as an
+   internal service, all a client can do is crash its own authenticated
+   connection.
+
+o  CVE-2018-1057:
+   On a Samba 4 AD DC the LDAP server in all versions of Samba from
+   4.0.0 onwards incorrectly validates permissions to modify passwords
+   over LDAP allowing authenticated users to change any other users'
+   passwords, including administrative users.
+
+   Possible workarounds are described at a dedicated page in the Samba wiki:
+   https://wiki.samba.org/index.php/CVE-2018-1057
+
+
+Changes since 4.5.15:
+---------------------
+
+o  Jeremy Allison <jra@samba.org>
+   * BUG 11343: CVE-2018-1050: Codenomicon crashes in spoolss server code.
+
+o  Ralph Boehme <slow@samba.org>
+   * BUG 13272: CVE-2018-1057: Unprivileged user can change any user (and admin)
+     password.
+
+o  Stefan Metzmacher <metze@samba.org>
+   * BUG 13272: CVE-2018-1057: Unprivileged user can change any user (and admin)
+     password.
+
+
+#######################################
+Reporting bugs & Development Discussion
+#######################################
+
+Please discuss this release on the samba-technical mailing list or by
+joining the #samba-technical IRC channel on irc.freenode.net.
+
+If you do report problems then please try to send high quality
+feedback. If you don't provide vital information to help us track down
+the problem then you will probably be ignored.  All bug reports should
+be filed under the "Samba 4.1 and newer" product in the project's Bugzilla
+database (https://bugzilla.samba.org/).
+
+
+======================================================================
+== Our Code, Our Bugs, Our Responsibility.
+== The Samba Team
+======================================================================
+
+
+Release notes for older releases follow:
+----------------------------------------
+
+                   ==============================
                    Release Notes for Samba 4.5.15
                           November 21, 2017
                    ==============================
@@ -66,8 +142,8 @@ database (https://bugzilla.samba.org/).
 ======================================================================
 
 
-Release notes for older releases follow:
-----------------------------------------
+----------------------------------------------------------------------
+
 
                    ==============================
                    Release Notes for Samba 4.5.14
diff --git a/source3/rpc_server/spoolss/srv_spoolss_nt.c b/source3/rpc_server/spoolss/srv_spoolss_nt.c
index a3c3861202d..fb56e2bf9a6 100644
--- a/source3/rpc_server/spoolss/srv_spoolss_nt.c
+++ b/source3/rpc_server/spoolss/srv_spoolss_nt.c
@@ -178,6 +178,11 @@ static void prune_printername_cache(void);
 static const char *canon_servername(const char *servername)
 {
 	const char *pservername = servername;
+
+	if (servername == NULL) {
+		return "";
+	}
+
 	while (*pservername == '\\') {
 		pservername++;
 	}
@@ -2073,6 +2078,10 @@ WERROR _spoolss_DeletePrinterDriver(struct pipes_struct *p,
 		return WERR_ACCESS_DENIED;
 	}
 
+	if (r->in.architecture == NULL || r->in.driver == NULL) {
+		return WERR_INVALID_ENVIRONMENT;
+	}
+
 	/* check that we have a valid driver name first */
 
 	if ((version = get_version_id(r->in.architecture)) == -1) {
@@ -2212,6 +2221,10 @@ WERROR _spoolss_DeletePrinterDriverEx(struct pipes_struct *p,
 		return WERR_ACCESS_DENIED;
 	}
 
+	if (r->in.architecture == NULL || r->in.driver == NULL) {
+		return WERR_INVALID_ENVIRONMENT;
+	}
+
 	/* check that we have a valid driver name first */
 	if (get_version_id(r->in.architecture) == -1) {
 		/* this is what NT returns */
diff --git a/source4/dsdb/samdb/ldb_modules/acl.c b/source4/dsdb/samdb/ldb_modules/acl.c
index 27d4e7659cc..d750362c47f 100644
--- a/source4/dsdb/samdb/ldb_modules/acl.c
+++ b/source4/dsdb/samdb/ldb_modules/acl.c
@@ -966,11 +966,79 @@ static int acl_check_password_rights(TALLOC_CTX *mem_ctx,
 {
 	int ret = LDB_SUCCESS;
 	unsigned int del_attr_cnt = 0, add_attr_cnt = 0, rep_attr_cnt = 0;
+	unsigned int del_val_cnt = 0, add_val_cnt = 0, rep_val_cnt = 0;
 	struct ldb_message_element *el;
 	struct ldb_message *msg;
+	struct ldb_control *c = NULL;
 	const char *passwordAttrs[] = { "userPassword", "clearTextPassword",
-					"unicodePwd", "dBCSPwd", NULL }, **l;
+					"unicodePwd", NULL }, **l;
 	TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
+	struct dsdb_control_password_acl_validation *pav = NULL;
+
+	if (tmp_ctx == NULL) {
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	pav = talloc_zero(req, struct dsdb_control_password_acl_validation);
+	if (pav == NULL) {
+		talloc_free(tmp_ctx);
+		return LDB_ERR_OPERATIONS_ERROR;
+	}
+
+	c = ldb_request_get_control(req, DSDB_CONTROL_PASSWORD_CHANGE_OID);
+	if (c != NULL) {
+		pav->pwd_reset = false;
+
+		/*
+		 * The "DSDB_CONTROL_PASSWORD_CHANGE_OID" control means that we
+		 * have a user password change and not a set as the message
+		 * looks like. In it's value blob it contains the NT and/or LM
+		 * hash of the old password specified by the user.  This control
+		 * is used by the SAMR and "kpasswd" password change mechanisms.
+		 *
+		 * This control can't be used by real LDAP clients,
+		 * the only caller is samdb_set_password_internal(),
+		 * so we don't have to strict verification of the input.
+		 */
+		ret = acl_check_extended_right(tmp_ctx,
+					       sd,
+					       acl_user_token(module),
+					       GUID_DRS_USER_CHANGE_PASSWORD,
+					       SEC_ADS_CONTROL_ACCESS,
+					       sid);
+		goto checked;
+	}
+
+	c = ldb_request_get_control(req, DSDB_CONTROL_PASSWORD_HASH_VALUES_OID);
+	if (c != NULL) {
+		pav->pwd_reset = true;
+
+		/*
+		 * The "DSDB_CONTROL_PASSWORD_HASH_VALUES_OID" control, without
+		 * "DSDB_CONTROL_PASSWORD_CHANGE_OID" control means that we
+		 * have a force password set.
+		 * This control is used by the SAMR/NETLOGON/LSA password
+		 * reset mechanisms.
+		 *
+		 * This control can't be used by real LDAP clients,
+		 * the only caller is samdb_set_password_internal(),
+		 * so we don't have to strict verification of the input.
+		 */
+		ret = acl_check_extended_right(tmp_ctx, sd, acl_user_token(module),
+					       GUID_DRS_FORCE_CHANGE_PASSWORD,
+					       SEC_ADS_CONTROL_ACCESS,
+					       sid);
+		goto checked;
+	}
+
+	el = ldb_msg_find_element(req->op.mod.message, "dBCSPwd");
+	if (el != NULL) {
+		/*
+		 * dBCSPwd is only allowed with a control.
+		 */
+		talloc_free(tmp_ctx);
+		return LDB_ERR_UNWILLING_TO_PERFORM;
+	}
 
 	msg = ldb_msg_copy_shallow(tmp_ctx, req->op.mod.message);
 	if (msg == NULL) {
@@ -984,12 +1052,15 @@ static int acl_check_password_rights(TALLOC_CTX *mem_ctx,
 		while ((el = ldb_msg_find_element(msg, *l)) != NULL) {
 			if (LDB_FLAG_MOD_TYPE(el->flags) == LDB_FLAG_MOD_DELETE) {
 				++del_attr_cnt;
+				del_val_cnt += el->num_values;
 			}
 			if (LDB_FLAG_MOD_TYPE(el->flags) == LDB_FLAG_MOD_ADD) {
 				++add_attr_cnt;
+				add_val_cnt += el->num_values;
 			}
 			if (LDB_FLAG_MOD_TYPE(el->flags) == LDB_FLAG_MOD_REPLACE) {
 				++rep_attr_cnt;
+				rep_val_cnt += el->num_values;
 			}
 			ldb_msg_remove_element(msg, el);
 		}
@@ -1002,26 +1073,30 @@ static int acl_check_password_rights(TALLOC_CTX *mem_ctx,
 		return LDB_SUCCESS;
 	}
 
-	if (ldb_request_get_control(req,
-				    DSDB_CONTROL_PASSWORD_CHANGE_OID) != NULL) {
-		/* The "DSDB_CONTROL_PASSWORD_CHANGE_OID" control means that we
-		 * have a user password change and not a set as the message
-		 * looks like. In it's value blob it contains the NT and/or LM
-		 * hash of the old password specified by the user.
-		 * This control is used by the SAMR and "kpasswd" password
-		 * change mechanisms. */
+
+	if (rep_attr_cnt > 0) {
+		pav->pwd_reset = true;
+
 		ret = acl_check_extended_right(tmp_ctx, sd, acl_user_token(module),
-					       GUID_DRS_USER_CHANGE_PASSWORD,
+					       GUID_DRS_FORCE_CHANGE_PASSWORD,
 					       SEC_ADS_CONTROL_ACCESS,
 					       sid);
+		goto checked;
 	}
-	else if (rep_attr_cnt > 0 || (add_attr_cnt != del_attr_cnt)) {
+
+	if (add_attr_cnt != del_attr_cnt) {
+		pav->pwd_reset = true;
+
 		ret = acl_check_extended_right(tmp_ctx, sd, acl_user_token(module),
 					       GUID_DRS_FORCE_CHANGE_PASSWORD,
 					       SEC_ADS_CONTROL_ACCESS,
 					       sid);
+		goto checked;
 	}
-	else if (add_attr_cnt == 1 && del_attr_cnt == 1) {
+
+	if (add_val_cnt == 1 && del_val_cnt == 1) {
+		pav->pwd_reset = false;
+
 		ret = acl_check_extended_right(tmp_ctx, sd, acl_user_token(module),
 					       GUID_DRS_USER_CHANGE_PASSWORD,
 					       SEC_ADS_CONTROL_ACCESS,
@@ -1030,17 +1105,53 @@ static int acl_check_password_rights(TALLOC_CTX *mem_ctx,
 		if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
 			ret = LDB_ERR_CONSTRAINT_VIOLATION;
 		}
+		goto checked;
+	}
+
+	if (add_val_cnt == 1 && del_val_cnt == 0) {
+		pav->pwd_reset = true;
+
+		ret = acl_check_extended_right(tmp_ctx, sd, acl_user_token(module),
+					       GUID_DRS_FORCE_CHANGE_PASSWORD,
+					       SEC_ADS_CONTROL_ACCESS,
+					       sid);
+		/* Very strange, but we get constraint violation in this case */
+		if (ret == LDB_ERR_INSUFFICIENT_ACCESS_RIGHTS) {
+			ret = LDB_ERR_CONSTRAINT_VIOLATION;
+		}
+		goto checked;
 	}
+
+	/*
+	 * Everything else is handled by the password_hash module where it will
+	 * fail, but with the correct error code when the module is again
+	 * checking the attributes. As the change request will lack the
+	 * DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID control, we can be sure that
+	 * any modification attempt that went this way will be rejected.
+	 */
+
+	talloc_free(tmp_ctx);
+	return LDB_SUCCESS;
+
+checked:
 	if (ret != LDB_SUCCESS) {
 		dsdb_acl_debug(sd, acl_user_token(module),
 			       req->op.mod.message->dn,
 			       true,
 			       10);
+		talloc_free(tmp_ctx);
+		return ret;
 	}
-	talloc_free(tmp_ctx);
-	return ret;
-}
 
+	ret = ldb_request_add_control(req,
+		DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID, false, pav);
+	if (ret != LDB_SUCCESS) {
+		ldb_debug(ldb_module_get_ctx(module), LDB_DEBUG_ERROR,
+			  "Unable to register ACL validation control!\n");
+		return ret;
+	}
+	return LDB_SUCCESS;
+}
 
 static int acl_modify(struct ldb_module *module, struct ldb_request *req)
 {
@@ -1055,6 +1166,7 @@ static int acl_modify(struct ldb_module *module, struct ldb_request *req)
 	struct ldb_control *as_system;
 	struct ldb_control *is_undelete;
 	bool userPassword;
+	bool password_rights_checked = false;
 	TALLOC_CTX *tmp_ctx;
 	const struct ldb_message *msg = req->op.mod.message;
 	static const char *acl_attrs[] = {
@@ -1200,6 +1312,9 @@ static int acl_modify(struct ldb_module *module, struct ldb_request *req)
 		} else if (ldb_attr_cmp("unicodePwd", el->name) == 0 ||
 			   (userPassword && ldb_attr_cmp("userPassword", el->name) == 0) ||
 			   ldb_attr_cmp("clearTextPassword", el->name) == 0) {
+			if (password_rights_checked) {
+				continue;
+			}
 			ret = acl_check_password_rights(tmp_ctx,
 							module,
 							req,
@@ -1210,6 +1325,7 @@ static int acl_modify(struct ldb_module *module, struct ldb_request *req)
 			if (ret != LDB_SUCCESS) {
 				goto fail;
 			}
+			password_rights_checked = true;
 		} else if (ldb_attr_cmp("servicePrincipalName", el->name) == 0) {
 			ret = acl_check_spn(tmp_ctx,
 					    module,
diff --git a/source4/dsdb/samdb/ldb_modules/password_hash.c b/source4/dsdb/samdb/ldb_modules/password_hash.c
index e5bee6fae53..06abf66f1a7 100644
--- a/source4/dsdb/samdb/ldb_modules/password_hash.c
+++ b/source4/dsdb/samdb/ldb_modules/password_hash.c
@@ -3188,7 +3188,35 @@ static int setup_io(struct ph_context *ac,
 		/* On "add" we have only "password reset" */
 		ac->pwd_reset = true;
 	} else if (ac->req->operation == LDB_MODIFY) {
-		if (io->og.cleartext_utf8 || io->og.cleartext_utf16
+		struct ldb_control *pav_ctrl = NULL;
+		struct dsdb_control_password_acl_validation *pav = NULL;
+
+		pav_ctrl = ldb_request_get_control(ac->req,
+				DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID);
+		if (pav_ctrl != NULL) {
+			pav = talloc_get_type_abort(pav_ctrl->data,
+				struct dsdb_control_password_acl_validation);
+		}
+
+		if (pav == NULL && ac->update_password) {
+			bool ok;
+
+			/*
+			 * If the DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID
+			 * control is missing, we require system access!
+			 */
+			ok = dsdb_module_am_system(ac->module);
+			if (!ok) {
+				return ldb_module_operr(ac->module);
+			}
+		}
+
+		if (pav != NULL) {
+			/*
+			 * We assume what the acl module has validated.
+			 */
+			ac->pwd_reset = pav->pwd_reset;
+		} else if (io->og.cleartext_utf8 || io->og.cleartext_utf16
 		    || io->og.nt_hash || io->og.lm_hash) {
 			/* If we have an old password specified then for sure it
 			 * is a user "password change" */
@@ -3921,25 +3949,26 @@ static int password_hash_modify(struct ldb_module *module, struct ldb_request *r
 		}
 
 		while ((passwordAttr = ldb_msg_find_element(msg, *l)) != NULL) {
-			if (LDB_FLAG_MOD_TYPE(passwordAttr->flags) == LDB_FLAG_MOD_DELETE) {
+			unsigned int mtype = LDB_FLAG_MOD_TYPE(passwordAttr->flags);
+			unsigned int nvalues = passwordAttr->num_values;
+
+			if (mtype == LDB_FLAG_MOD_DELETE) {
 				++del_attr_cnt;
 			}
-			if (LDB_FLAG_MOD_TYPE(passwordAttr->flags) == LDB_FLAG_MOD_ADD) {
+			if (mtype == LDB_FLAG_MOD_ADD) {
 				++add_attr_cnt;
 			}
-			if (LDB_FLAG_MOD_TYPE(passwordAttr->flags) == LDB_FLAG_MOD_REPLACE) {
+			if (mtype == LDB_FLAG_MOD_REPLACE) {
 				++rep_attr_cnt;
 			}
-			if ((passwordAttr->num_values != 1) &&
-			    (LDB_FLAG_MOD_TYPE(passwordAttr->flags) == LDB_FLAG_MOD_ADD)) {
+			if ((nvalues != 1) && (mtype == LDB_FLAG_MOD_ADD)) {
 				talloc_free(ac);
 				ldb_asprintf_errstring(ldb,
 						       "'%s' attribute must have exactly one value on add operations!",
 						       *l);
 				return LDB_ERR_CONSTRAINT_VIOLATION;
 			}
-			if ((passwordAttr->num_values > 1) &&
-			    (LDB_FLAG_MOD_TYPE(passwordAttr->flags) == LDB_FLAG_MOD_DELETE)) {
+			if ((nvalues > 1) && (mtype == LDB_FLAG_MOD_DELETE)) {
 				talloc_free(ac);
 				ldb_asprintf_errstring(ldb,
 						       "'%s' attribute must have zero or one value(s) on delete operations!",
diff --git a/source4/dsdb/samdb/samdb.h b/source4/dsdb/samdb/samdb.h
index 586a3bfaf0e..6390258141e 100644
--- a/source4/dsdb/samdb/samdb.h
+++ b/source4/dsdb/samdb/samdb.h
@@ -182,6 +182,15 @@ struct dsdb_control_password_user_account_control {
 /* passed when we want to thoroughly delete linked attributes */
 #define DSDB_CONTROL_REPLMD_VANISH_LINKS "1.3.6.1.4.1.7165.4.3.29"
 
+/*
+ * Used to pass "user password change" vs "password reset" from the ACL to the
+ * password_hash module, ensuring both modules treat the request identical.
+ */
+#define DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID "1.3.6.1.4.1.7165.4.3.33"
+struct dsdb_control_password_acl_validation {
+	bool pwd_reset;
+};
+
 #define DSDB_EXTENDED_REPLICATED_OBJECTS_OID "1.3.6.1.4.1.7165.4.4.1"
 struct dsdb_extended_replicated_object {
 	struct ldb_message *msg;
diff --git a/source4/dsdb/tests/python/passwords.py b/source4/dsdb/tests/python/passwords.py
index db013ea46ad..be1f34d2312 100755
--- a/source4/dsdb/tests/python/passwords.py
+++ b/source4/dsdb/tests/python/passwords.py
@@ -1020,6 +1020,55 @@ userPassword: thatsAcomplPASS4
         # Reset the "minPwdLength" as it was before
         self.ldb.set_minPwdLength(minPwdLength)
 
+    def test_pw_change_delete_no_value_userPassword(self):
+        """Test password change with userPassword where the delete attribute doesn't have a value"""
+
+        try:
+            self.ldb2.modify_ldif("""
+dn: cn=testuser,cn=users,""" + self.base_dn + """
+changetype: modify
+delete: userPassword
+add: userPassword
+userPassword: thatsAcomplPASS1
+""")
+        except LdbError, (num, msg):
+            self.assertEquals(num, ERR_CONSTRAINT_VIOLATION)
+        else:
+            self.fail()
+
+    def test_pw_change_delete_no_value_clearTextPassword(self):
+        """Test password change with clearTextPassword where the delete attribute doesn't have a value"""
+
+        try:
+            self.ldb2.modify_ldif("""
+dn: cn=testuser,cn=users,""" + self.base_dn + """
+changetype: modify
+delete: clearTextPassword
+add: clearTextPassword
+clearTextPassword: thatsAcomplPASS2
+""")
+        except LdbError, (num, msg):
+            self.assertTrue(num == ERR_CONSTRAINT_VIOLATION or
+                            num == ERR_NO_SUCH_ATTRIBUTE) # for Windows
+        else:
+            self.fail()
+
+    def test_pw_change_delete_no_value_unicodePwd(self):
+        """Test password change with unicodePwd where the delete attribute doesn't have a value"""
+
+        try:
+            self.ldb2.modify_ldif("""
+dn: cn=testuser,cn=users,""" + self.base_dn + """
+changetype: modify
+delete: unicodePwd
+add: unicodePwd
+unicodePwd:: """ + base64.b64encode("\"thatsAcomplPASS3\"".encode('utf-16-le')) + """
+""")
+        except LdbError, (num, msg):
+            self.assertEquals(num, ERR_CONSTRAINT_VIOLATION)
+        else:
+            self.fail()
+
     def tearDown(self):
         super(PasswordTests, self).tearDown()
         delete_force(self.ldb, "cn=testuser,cn=users," + self.base_dn)
diff --git a/source4/libcli/ldap/ldap_controls.c b/source4/libcli/ldap/ldap_controls.c
index 9df95c32a9d..7ecc9080cd1 100644
--- a/source4/libcli/ldap/ldap_controls.c
+++ b/source4/libcli/ldap/ldap_controls.c
@@ -1262,6 +1262,7 @@ static const struct ldap_control_handler ldap_known_controls[] = {
 	{ DSDB_CONTROL_PASSWORD_CHANGE_STATUS_OID, NULL, NULL },
 	{ DSDB_CONTROL_PASSWORD_HASH_VALUES_OID, NULL, NULL },
 	{ DSDB_CONTROL_PASSWORD_CHANGE_OID, NULL, NULL },
+	{ DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID, NULL, NULL },
 	{ DSDB_CONTROL_APPLY_LINKS, NULL, NULL },
 	{ LDB_CONTROL_BYPASS_OPERATIONAL_OID, NULL, NULL },
 	{ DSDB_CONTROL_CHANGEREPLMETADATA_OID, NULL, NULL },
diff --git a/source4/setup/schema_samba4.ldif b/source4/setup/schema_samba4.ldif
index 04505de2daf..0a27f8a991e 100644
--- a/source4/setup/schema_samba4.ldif
+++ b/source4/setup/schema_samba4.ldif
@@ -217,6 +217,8 @@
 #Allocated: DSDB_CONTROL_PASSWORD_USER_ACCOUNT_CONTROL_OID 1.3.6.1.4.1.7165.4.3.27
 #Allocated: DSDB_CONTROL_SKIP_DUPLICATES_CHECK_OID 1.3.6.1.4.1.7165.4.3.28
 #Allocated: DSDB_CONTROL_REPLMD_VANISH_LINKS 1.3.6.1.4.1.7165.4.3.29
+#Allocated: DSDB_CONTROL_PASSWORD_ACL_VALIDATION_OID 1.3.6.1.4.1.7165.4.3.33
+
 
 # Extended 1.3.6.1.4.1.7165.4.4.x
 #Allocated: DSDB_EXTENDED_REPLICATED_OBJECTS_OID 1.3.6.1.4.1.7165.4.4.1