Add rest of user auth queries

Reviewers: mferencevic, teon.banek

Reviewed By: mferencevic, teon.banek

Subscribers: pullbot

Differential Revision: https://phabricator.memgraph.io/D1522

src/query/frontend/ast/ast.capnp

@@ -132,14 +132,13 @@ struct Clause {
     merge @10 :Merge;
     unwind @11 :Unwind;
     createIndex @12 :CreateIndex;
-    modifyUser @13 :ModifyUser;
+    authQuery @13 :AuthQuery;
-    dropUser @14 :DropUser;
+    createStream @14 :CreateStream;
-    createStream @15 :CreateStream;
+    dropStream @15 :DropStream;
-    dropStream @16 :DropStream;
+    showStreams @16 :ShowStreams;
-    showStreams @17 :ShowStreams;
+    startStopStream @17 :StartStopStream;
-    startStopStream @18 :StartStopStream;
+    startStopAllStreams @18 :StartStopAllStreams;
-    startStopAllStreams @19 :StartStopAllStreams;
+    testStream @19 :TestStream;
-    testStream @20 :TestStream;
   }
 }
 
@@ -398,14 +397,39 @@ struct CreateIndex {
   property @1 :Storage.Common;
 }
 
-struct ModifyUser {
+struct AuthQuery {
-  username @0 :Text;
+  enum Action {
-  password @1 :Tree;
+    createRole @0;
-  isCreate @2 :Bool;
+    dropRole @1;
-}
+    showRoles @2;
-
+    createUser @3;
-struct DropUser {
+    setPassword @4;
-  usernames @0 :List(Text);
+    dropUser @5;
+    showUsers @6;
+    grantRole @7;
+    revokeRole @8;
+    grantPrivilege @9;
+    denyPrivilege @10;
+    revokePrivilege @11;
+    showGrants @12;
+    showRoleForUser @13;
+    showUsersForRole @14;
+  }
+  enum Privilege {
+    create @0;
+    delete @1;
+    match @2;
+    merge @3;
+    set @4;
+    auth @5;
+    stream @6;
+  }
+  action @0 :Action;
+  user @1 :Text;
+  role @2 :Text;
+  userOrRole @3 :Text;
+  password @4 :Tree;
+  privileges @5 :List(Privilege);  
 }
 
 struct CreateStream {

src/query/frontend/ast/ast.cpp

@@ -1268,13 +1268,9 @@ Clause *Clause::Construct(const capnp::Clause::Reader &reader,
       auto with_reader = reader.getWith();
       return With::Construct(with_reader, storage);
     }
-    case capnp::Clause::MODIFY_USER: {
+    case capnp::Clause::AUTH_QUERY: {
-      auto mu_reader = reader.getModifyUser();
+      auto aq_reader = reader.getAuthQuery();
-      return ModifyUser::Construct(mu_reader, storage);
+      return AuthQuery::Construct(aq_reader, storage);
-    }
-    case capnp::Clause::DROP_USER: {
-      auto du_reader = reader.getDropUser();
-      return DropUser::Construct(du_reader, storage);
     }
     case capnp::Clause::CREATE_STREAM: {
       auto cs_reader = reader.getCreateStream();
@@ -2067,69 +2063,188 @@ With *With::Construct(const capnp::With::Reader &reader, AstStorage *storage) {
   return storage->Create<With>();
 }
 
-// ModifyUser.
+// AuthQuery.
-void ModifyUser::Save(capnp::Clause::Builder *clause_builder,
+void AuthQuery::Save(capnp::Clause::Builder *clause_builder,
-                      std::vector<int> *saved_uids) {
+                     std::vector<int> *saved_uids) {
   Clause::Save(clause_builder, saved_uids);
-  auto builder = clause_builder->initModifyUser();
+  auto builder = clause_builder->initAuthQuery();
-  ModifyUser::Save(&builder, saved_uids);
+  AuthQuery::Save(&builder, saved_uids);
 }
 
-void ModifyUser::Save(capnp::ModifyUser::Builder *builder,
+void AuthQuery::Save(capnp::AuthQuery::Builder *builder,
-                      std::vector<int> *saved_uids) {
+                     std::vector<int> *saved_uids) {
-  builder->setUsername(username_);
+  switch (action_) {
+    case Action::CREATE_ROLE:
+      builder->setAction(capnp::AuthQuery::Action::CREATE_ROLE);
+      break;
+    case Action::DROP_ROLE:
+      builder->setAction(capnp::AuthQuery::Action::DROP_ROLE);
+      break;
+    case Action::SHOW_ROLES:
+      builder->setAction(capnp::AuthQuery::Action::SHOW_ROLES);
+      break;
+    case Action::CREATE_USER:
+      builder->setAction(capnp::AuthQuery::Action::CREATE_USER);
+      break;
+    case Action::SET_PASSWORD:
+      builder->setAction(capnp::AuthQuery::Action::SET_PASSWORD);
+      break;
+    case Action::DROP_USER:
+      builder->setAction(capnp::AuthQuery::Action::DROP_USER);
+      break;
+    case Action::SHOW_USERS:
+      builder->setAction(capnp::AuthQuery::Action::SHOW_USERS);
+      break;
+    case Action::GRANT_ROLE:
+      builder->setAction(capnp::AuthQuery::Action::GRANT_ROLE);
+      break;
+    case Action::REVOKE_ROLE:
+      builder->setAction(capnp::AuthQuery::Action::REVOKE_ROLE);
+      break;
+    case Action::GRANT_PRIVILEGE:
+      builder->setAction(capnp::AuthQuery::Action::GRANT_PRIVILEGE);
+      break;
+    case Action::DENY_PRIVILEGE:
+      builder->setAction(capnp::AuthQuery::Action::DENY_PRIVILEGE);
+      break;
+    case Action::REVOKE_PRIVILEGE:
+      builder->setAction(capnp::AuthQuery::Action::REVOKE_PRIVILEGE);
+      break;
+    case Action::SHOW_GRANTS:
+      builder->setAction(capnp::AuthQuery::Action::SHOW_GRANTS);
+      break;
+    case Action::SHOW_ROLE_FOR_USER:
+      builder->setAction(capnp::AuthQuery::Action::SHOW_ROLE_FOR_USER);
+      break;
+    case Action::SHOW_USERS_FOR_ROLE:
+      builder->setAction(capnp::AuthQuery::Action::SHOW_USERS_FOR_ROLE);
+      break;
+  }
+  builder->setUser(user_);
+  builder->setRole(role_);
+  builder->setUserOrRole(user_or_role_);
   if (password_) {
-    auto password_builder = builder->getPassword();
+    auto password_builder = builder->initPassword();
     password_->Save(&password_builder, saved_uids);
   }
-  builder->setIsCreate(is_create_);
+  ::capnp::List<capnp::AuthQuery::Privilege>::Builder privileges_builder =
+      builder->initPrivileges(privileges_.size());
+  for (size_t i = 0; i < privileges_.size(); ++i) {
+    switch (privileges_[i]) {
+      case Privilege::CREATE:
+        privileges_builder.set(i, capnp::AuthQuery::Privilege::CREATE);
+        break;
+      case Privilege::DELETE:
+        privileges_builder.set(i, capnp::AuthQuery::Privilege::DELETE);
+        break;
+      case Privilege::MATCH:
+        privileges_builder.set(i, capnp::AuthQuery::Privilege::MATCH);
+        break;
+      case Privilege::MERGE:
+        privileges_builder.set(i, capnp::AuthQuery::Privilege::MERGE);
+        break;
+      case Privilege::SET:
+        privileges_builder.set(i, capnp::AuthQuery::Privilege::SET);
+        break;
+      case Privilege::AUTH:
+        privileges_builder.set(i, capnp::AuthQuery::Privilege::AUTH);
+        break;
+      case Privilege::STREAM:
+        privileges_builder.set(i, capnp::AuthQuery::Privilege::STREAM);
+        break;
+    }
+  }
 }
 
-void ModifyUser::Load(const capnp::Tree::Reader &base_reader,
+void AuthQuery::Load(const capnp::Tree::Reader &base_reader,
-                      AstStorage *storage, std::vector<int> *loaded_uids) {
+                     AstStorage *storage, std::vector<int> *loaded_uids) {
   Clause::Load(base_reader, storage, loaded_uids);
-  auto reader = base_reader.getClause().getModifyUser();
+  auto auth_reader = base_reader.getClause().getAuthQuery();
-  username_ = reader.getUsername();
+  switch (auth_reader.getAction()) {
-  if (reader.hasPassword()) {
+    case capnp::AuthQuery::Action::CREATE_ROLE:
-    const auto password_reader = reader.getPassword();
+      action_ = Action::CREATE_ROLE;
+      break;
+    case capnp::AuthQuery::Action::DROP_ROLE:
+      action_ = Action::DROP_ROLE;
+      break;
+    case capnp::AuthQuery::Action::SHOW_ROLES:
+      action_ = Action::SHOW_ROLES;
+      break;
+    case capnp::AuthQuery::Action::CREATE_USER:
+      action_ = Action::CREATE_USER;
+      break;
+    case capnp::AuthQuery::Action::SET_PASSWORD:
+      action_ = Action::SET_PASSWORD;
+      break;
+    case capnp::AuthQuery::Action::DROP_USER:
+      action_ = Action::DROP_USER;
+      break;
+    case capnp::AuthQuery::Action::SHOW_USERS:
+      action_ = Action::SHOW_USERS;
+      break;
+    case capnp::AuthQuery::Action::GRANT_ROLE:
+      action_ = Action::GRANT_ROLE;
+      break;
+    case capnp::AuthQuery::Action::REVOKE_ROLE:
+      action_ = Action::REVOKE_ROLE;
+      break;
+    case capnp::AuthQuery::Action::GRANT_PRIVILEGE:
+      action_ = Action::GRANT_PRIVILEGE;
+      break;
+    case capnp::AuthQuery::Action::DENY_PRIVILEGE:
+      action_ = Action::DENY_PRIVILEGE;
+      break;
+    case capnp::AuthQuery::Action::REVOKE_PRIVILEGE:
+      action_ = Action::REVOKE_PRIVILEGE;
+      break;
+    case capnp::AuthQuery::Action::SHOW_GRANTS:
+      action_ = Action::SHOW_GRANTS;
+      break;
+    case capnp::AuthQuery::Action::SHOW_ROLE_FOR_USER:
+      action_ = Action::SHOW_ROLE_FOR_USER;
+      break;
+    case capnp::AuthQuery::Action::SHOW_USERS_FOR_ROLE:
+      action_ = Action::SHOW_USERS_FOR_ROLE;
+      break;
+  }
+  user_ = auth_reader.getUser();
+  role_ = auth_reader.getRole();
+  user_or_role_ = auth_reader.getUserOrRole();
+  if (auth_reader.hasPassword()) {
+    const auto password_reader = auth_reader.getPassword();
     password_ =
         dynamic_cast<Expression *>(storage->Load(password_reader, loaded_uids));
-  } else {
-    password_ = nullptr;
   }
-  is_create_ = reader.getIsCreate();
+  for (const auto &privilege : auth_reader.getPrivileges()) {
+    switch (privilege) {
+      case capnp::AuthQuery::Privilege::CREATE:
+        privileges_.push_back(Privilege::CREATE);
+        break;
+      case capnp::AuthQuery::Privilege::DELETE:
+        privileges_.push_back(Privilege::DELETE);
+        break;
+      case capnp::AuthQuery::Privilege::MATCH:
+        privileges_.push_back(Privilege::MATCH);
+        break;
+      case capnp::AuthQuery::Privilege::MERGE:
+        privileges_.push_back(Privilege::MERGE);
+        break;
+      case capnp::AuthQuery::Privilege::SET:
+        privileges_.push_back(Privilege::SET);
+        break;
+      case capnp::AuthQuery::Privilege::AUTH:
+        privileges_.push_back(Privilege::AUTH);
+        break;
+      case capnp::AuthQuery::Privilege::STREAM:
+        privileges_.push_back(Privilege::STREAM);
+        break;
+    }
+  }
 }
 
-ModifyUser *ModifyUser::Construct(const capnp::ModifyUser::Reader &reader,
+AuthQuery *AuthQuery::Construct(const capnp::AuthQuery::Reader &reader,
-                                  AstStorage *storage) {
+                                AstStorage *storage) {
-  return storage->Create<ModifyUser>();
+  return storage->Create<AuthQuery>();
-}
-
-// DropUser.
-void DropUser::Save(capnp::Clause::Builder *clause_builder,
-                    std::vector<int> *saved_uids) {
-  Clause::Save(clause_builder, saved_uids);
-  auto builder = clause_builder->initDropUser();
-  DropUser::Save(&builder, saved_uids);
-}
-
-void DropUser::Save(capnp::DropUser::Builder *builder,
-                    std::vector<int> *saved_uids) {
-  auto usernames_builder = builder->initUsernames(usernames_.size());
-  utils::SaveVector(usernames_, &usernames_builder);
-}
-
-void DropUser::Load(const capnp::Tree::Reader &base_reader, AstStorage *storage,
-                    std::vector<int> *loaded_uids) {
-  Clause::Load(base_reader, storage, loaded_uids);
-  auto reader = base_reader.getClause().getDropUser();
-  usernames_.clear();
-  utils::LoadVector(&usernames_, reader.getUsernames());
-}
-
-DropUser *DropUser::Construct(const capnp::DropUser::Reader &reader,
-                              AstStorage *storage) {
-  return storage->Create<DropUser>();
 }
 
 // CypherUnion

src/query/frontend/ast/ast.hpp

@@ -2339,68 +2339,67 @@ class CreateIndex : public Clause {
                     std::vector<int> *saved_uids);
 };
 
-class ModifyUser : public Clause {
+class AuthQuery : public Clause {
   friend class AstStorage;
 
  public:
+  enum class Action {
+    CREATE_ROLE,
+    DROP_ROLE,
+    SHOW_ROLES,
+    CREATE_USER,
+    SET_PASSWORD,
+    DROP_USER,
+    SHOW_USERS,
+    GRANT_ROLE,
+    REVOKE_ROLE,
+    GRANT_PRIVILEGE,
+    DENY_PRIVILEGE,
+    REVOKE_PRIVILEGE,
+    SHOW_GRANTS,
+    SHOW_ROLE_FOR_USER,
+    SHOW_USERS_FOR_ROLE
+  };
+
+  enum class Privilege { CREATE, DELETE, MATCH, MERGE, SET, AUTH, STREAM };
+
+  Action action_;
+  std::string user_;
+  std::string role_;
+  std::string user_or_role_;
+  Expression *password_{nullptr};
+  std::vector<Privilege> privileges_;
+
   DEFVISITABLE(TreeVisitor<TypedValue>);
   DEFVISITABLE(HierarchicalTreeVisitor);
 
-  ModifyUser *Clone(AstStorage &storage) const override {
+  AuthQuery *Clone(AstStorage &storage) const override {
-    return storage.Create<ModifyUser>(
+    return storage.Create<AuthQuery>(
-        username_, password_ ? password_->Clone(storage) : nullptr, is_create_);
+        action_, user_, role_, user_or_role_,
+        password_ ? password_->Clone(storage) : nullptr, privileges_);
   }
 
-  static ModifyUser *Construct(const capnp::ModifyUser::Reader &reader,
+  static AuthQuery *Construct(const capnp::AuthQuery::Reader &reader,
-                               AstStorage *storage);
+                              AstStorage *storage);
   using Clause::Save;
 
-  std::string username_;
-  Expression *password_;
-  bool is_create_;
-
  protected:
-  explicit ModifyUser(int uid) : Clause(uid) {}
+  explicit AuthQuery(int uid) : Clause(uid) {}
-  ModifyUser(int uid, std::string username, Expression *password,
+
-             bool is_create)
+  explicit AuthQuery(int uid, Action action, std::string user, std::string role,
+                     std::string user_or_role, Expression *password,
+                     std::vector<Privilege> privileges)
       : Clause(uid),
-        username_(std::move(username)),
+        action_(action),
+        user_(user),
+        role_(role),
+        user_or_role_(user_or_role),
         password_(password),
-        is_create_(is_create) {}
+        privileges_(privileges) {}
 
   void Save(capnp::Clause::Builder *builder,
             std::vector<int> *saved_uids) override;
-  virtual void Save(capnp::ModifyUser::Builder *builder,
+  virtual void Save(capnp::AuthQuery::Builder *builder,
-                    std::vector<int> *saved_uids);
-  void Load(const capnp::Tree::Reader &base_reader, AstStorage *storage,
-            std::vector<int> *loaded_uids) override;
-};
-
-class DropUser : public Clause {
-  friend class AstStorage;
-
- public:
-  DEFVISITABLE(TreeVisitor<TypedValue>);
-  DEFVISITABLE(HierarchicalTreeVisitor);
-
-  DropUser *Clone(AstStorage &storage) const override {
-    return storage.Create<DropUser>(usernames_);
-  }
-
-  static DropUser *Construct(const capnp::DropUser::Reader &reader,
-                             AstStorage *storage);
-  using Clause::Save;
-
-  std::vector<std::string> usernames_;
-
- protected:
-  explicit DropUser(int uid) : Clause(uid) {}
-  DropUser(int uid, std::vector<std::string> usernames)
-      : Clause(uid), usernames_(usernames) {}
-
-  void Save(capnp::Clause::Builder *builder,
-            std::vector<int> *saved_uids) override;
-  virtual void Save(capnp::DropUser::Builder *builder,
                     std::vector<int> *saved_uids);
   void Load(const capnp::Tree::Reader &base_reader, AstStorage *storage,
             std::vector<int> *loaded_uids) override;

src/query/frontend/ast/ast_visitor.hpp

@@ -61,8 +61,7 @@ class RemoveLabels;
 class Merge;
 class Unwind;
 class CreateIndex;
-class ModifyUser;
+class AuthQuery;
-class DropUser;
 class CreateStream;
 class DropStream;
 class ShowStreams;
@@ -84,9 +83,9 @@ using TreeCompositeVisitor = ::utils::CompositeVisitor<
 
 using TreeLeafVisitor =
     ::utils::LeafVisitor<Identifier, PrimitiveLiteral, ParameterLookup,
-                         CreateIndex, ModifyUser, DropUser, CreateStream,
+                         CreateIndex, AuthQuery, CreateStream, DropStream,
-                         DropStream, ShowStreams, StartStopStream,
+                         ShowStreams, StartStopStream, StartStopAllStreams,
-                         StartStopAllStreams, TestStream>;
+                         TestStream>;
 
 class HierarchicalTreeVisitor : public TreeCompositeVisitor,
                                 public TreeLeafVisitor {
@@ -109,8 +108,7 @@ using TreeVisitor = ::utils::Visitor<
     Aggregation, Function, Reduce, Extract, All, Single, ParameterLookup,
     Create, Match, Return, With, Pattern, NodeAtom, EdgeAtom, Delete, Where,
     SetProperty, SetProperties, SetLabels, RemoveProperty, RemoveLabels, Merge,
-    Unwind, Identifier, PrimitiveLiteral, CreateIndex, ModifyUser, DropUser,
+    Unwind, Identifier, PrimitiveLiteral, CreateIndex, AuthQuery, CreateStream,
-    CreateStream, DropStream, ShowStreams, StartStopStream, StartStopAllStreams,
+    DropStream, ShowStreams, StartStopStream, StartStopAllStreams, TestStream>;
-    TestStream>;
 
 }  // namespace query

src/query/frontend/ast/cypher_main_visitor.cpp

@@ -5,6 +5,7 @@
 #include <codecvt>
 #include <cstring>
 #include <limits>
+#include <regex>
 #include <string>
 #include <tuple>
 #include <unordered_map>
@@ -28,13 +29,10 @@ antlrcpp::Any CypherMainVisitor::visitAuthQuery(
     MemgraphCypher::AuthQueryContext *ctx) {
   query_ = storage_.query();
   query_->single_query_ = storage_.Create<SingleQuery>();
-  Clause *clause = nullptr;
+  CHECK(ctx->children.size() == 1)
-  if (ctx->modifyUser()) {
+      << "AuthQuery should have exactly one child!";
-    clause = ctx->modifyUser()->accept(this).as<ModifyUser *>();
+  query_->single_query_->clauses_.push_back(
-  } else if (ctx->dropUser()) {
+      ctx->children[0]->accept(this).as<AuthQuery *>());
-    clause = ctx->dropUser()->accept(this).as<DropUser *>();
-  }
-  query_->single_query_->clauses_ = {clause};
   return query_;
 }
 
@@ -259,46 +257,224 @@ antlrcpp::Any CypherMainVisitor::visitCreateIndex(
 }
 
 /**
- * @return ModifyUser*
+ * @return std::string
  */
-antlrcpp::Any CypherMainVisitor::visitModifyUser(
+antlrcpp::Any CypherMainVisitor::visitUserOrRoleName(
-    MemgraphCypher::ModifyUserContext *ctx) {
+    MemgraphCypher::UserOrRoleNameContext *ctx) {
-  std::string username(ctx->userName->getText());
+  std::string value = ctx->symbolicName()->accept(this).as<std::string>();
-  Expression *password = nullptr;
+  const std::regex NAME_REGEX("[a-zA-Z0-9_.+-]+");
-  bool is_create = static_cast<bool>(ctx->CREATE());
+  if (!std::regex_match(value, NAME_REGEX)) {
-  for (auto option : ctx->modifyUserOption()) {
+    throw SyntaxException("invalid user or role name");
-    if (option->passwordOption()) {
-      if (password) {
-        throw QueryException("password should be set at most once");
-      }
-      password = option->passwordOption()->accept(this);
-      continue;
-    }
-    LOG(FATAL) << "Expected to handle all cases above.";
   }
-  return storage_.Create<ModifyUser>(username, password, is_create);
+  return value;
 }
 
 /**
- * @return Expression*
+ * @return AuthQuery*
  */
-antlrcpp::Any CypherMainVisitor::visitPasswordOption(
+antlrcpp::Any CypherMainVisitor::visitCreateRole(
-    MemgraphCypher::PasswordOptionContext *ctx) {
+    MemgraphCypher::CreateRoleContext *ctx) {
-  if (!ctx->literal()->StringLiteral() && !ctx->literal()->CYPHERNULL()) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::CREATE_ROLE;
+  auth->role_ = ctx->role->accept(this).as<std::string>();
+  return auth;
+}
+
+/**
+ * @return AuthQuery*
+ */
+antlrcpp::Any CypherMainVisitor::visitDropRole(
+    MemgraphCypher::DropRoleContext *ctx) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::DROP_ROLE;
+  auth->role_ = ctx->role->accept(this).as<std::string>();
+  return auth;
+}
+
+/**
+ * @return AuthQuery*
+ */
+antlrcpp::Any CypherMainVisitor::visitShowRoles(
+    MemgraphCypher::ShowRolesContext *ctx) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::SHOW_ROLES;
+  return auth;
+}
+
+/**
+ * @return AuthQuery*
+ */
+antlrcpp::Any CypherMainVisitor::visitCreateUser(
+    MemgraphCypher::CreateUserContext *ctx) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::CREATE_USER;
+  auth->user_ = ctx->user->accept(this).as<std::string>();
+  if (ctx->password) {
+    if (!ctx->password->StringLiteral() && !ctx->literal()->CYPHERNULL()) {
+      throw SyntaxException("password should be a string literal or NULL");
+    }
+    auth->password_ = ctx->password->accept(this);
+  }
+  return auth;
+}
+
+/**
+ * @return AuthQuery*
+ */
+antlrcpp::Any CypherMainVisitor::visitSetPassword(
+    MemgraphCypher::SetPasswordContext *ctx) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::SET_PASSWORD;
+  auth->user_ = ctx->user->accept(this).as<std::string>();
+  if (!ctx->password->StringLiteral() && !ctx->literal()->CYPHERNULL()) {
     throw SyntaxException("password should be a string literal or NULL");
   }
-  return ctx->literal()->accept(this);
+  auth->password_ = ctx->password->accept(this);
+  return auth;
 }
 
 /**
- * @return DropUser*
+ * @return AuthQuery*
  */
 antlrcpp::Any CypherMainVisitor::visitDropUser(
     MemgraphCypher::DropUserContext *ctx) {
-  std::vector<std::string> usernames;
+  AuthQuery *auth = storage_.Create<AuthQuery>();
-  for (auto username_ptr : ctx->userName)
+  auth->action_ = AuthQuery::Action::DROP_USER;
-    usernames.emplace_back(username_ptr->getText());
+  auth->user_ = ctx->user->accept(this).as<std::string>();
-  return storage_.Create<DropUser>(usernames);
+  return auth;
+}
+
+/**
+ * @return AuthQuery*
+ */
+antlrcpp::Any CypherMainVisitor::visitShowUsers(
+    MemgraphCypher::ShowUsersContext *ctx) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::SHOW_USERS;
+  return auth;
+}
+
+/**
+ * @return AuthQuery*
+ */
+antlrcpp::Any CypherMainVisitor::visitGrantRole(
+    MemgraphCypher::GrantRoleContext *ctx) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::GRANT_ROLE;
+  auth->role_ = ctx->role->accept(this).as<std::string>();
+  auth->user_ = ctx->user->accept(this).as<std::string>();
+  return auth;
+}
+
+/**
+ * @return AuthQuery*
+ */
+antlrcpp::Any CypherMainVisitor::visitRevokeRole(
+    MemgraphCypher::RevokeRoleContext *ctx) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::REVOKE_ROLE;
+  auth->role_ = ctx->role->accept(this).as<std::string>();
+  auth->user_ = ctx->user->accept(this).as<std::string>();
+  return auth;
+}
+
+/**
+ * @return AuthQuery*
+ */
+antlrcpp::Any CypherMainVisitor::visitGrantPrivilege(
+    MemgraphCypher::GrantPrivilegeContext *ctx) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::GRANT_PRIVILEGE;
+  auth->user_or_role_ = ctx->userOrRole->accept(this).as<std::string>();
+  for (auto *privilege : ctx->privilegeList()->privilege()) {
+    auth->privileges_.push_back(privilege->accept(this));
+  }
+  return auth;
+}
+
+/**
+ * @return AuthQuery*
+ */
+antlrcpp::Any CypherMainVisitor::visitDenyPrivilege(
+    MemgraphCypher::DenyPrivilegeContext *ctx) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::DENY_PRIVILEGE;
+  auth->user_or_role_ = ctx->userOrRole->accept(this).as<std::string>();
+  for (auto *privilege : ctx->privilegeList()->privilege()) {
+    auth->privileges_.push_back(privilege->accept(this));
+  }
+  return auth;
+}
+
+/**
+ * @return AuthQuery*
+ */
+antlrcpp::Any CypherMainVisitor::visitRevokePrivilege(
+    MemgraphCypher::RevokePrivilegeContext *ctx) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::REVOKE_PRIVILEGE;
+  auth->user_or_role_ = ctx->userOrRole->accept(this).as<std::string>();
+  if (ctx->privilegeList()) {
+    for (auto *privilege : ctx->privilegeList()->privilege()) {
+      auth->privileges_.push_back(privilege->accept(this));
+    }
+  } else {
+    /* revoke all privileges */
+    auth->privileges_ = {
+        AuthQuery::Privilege::CREATE, AuthQuery::Privilege::DELETE,
+        AuthQuery::Privilege::MATCH,  AuthQuery::Privilege::MERGE,
+        AuthQuery::Privilege::SET,    AuthQuery::Privilege::AUTH,
+        AuthQuery::Privilege::STREAM};
+  }
+  return auth;
+}
+
+/**
+ * @return AuthQuery::Privilege
+ */
+antlrcpp::Any CypherMainVisitor::visitPrivilege(
+    MemgraphCypher::PrivilegeContext *ctx) {
+  if (ctx->CREATE()) return AuthQuery::Privilege::CREATE;
+  if (ctx->DELETE()) return AuthQuery::Privilege::DELETE;
+  if (ctx->MATCH()) return AuthQuery::Privilege::MATCH;
+  if (ctx->MERGE()) return AuthQuery::Privilege::MERGE;
+  if (ctx->SET()) return AuthQuery::Privilege::SET;
+  if (ctx->AUTH()) return AuthQuery::Privilege::AUTH;
+  if (ctx->STREAM()) return AuthQuery::Privilege::STREAM;
+  LOG(FATAL) << "Should not get here - unknown privilege!";
+}
+
+/**
+ * @return AuthQuery*
+ */
+antlrcpp::Any CypherMainVisitor::visitShowGrants(
+    MemgraphCypher::ShowGrantsContext *ctx) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::SHOW_GRANTS;
+  auth->user_or_role_ = ctx->userOrRole->accept(this).as<std::string>();
+  return auth;
+}
+
+/**
+ * @return AuthQuery*
+ */
+antlrcpp::Any CypherMainVisitor::visitShowRoleForUser(
+    MemgraphCypher::ShowRoleForUserContext *ctx) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::SHOW_ROLE_FOR_USER;
+  auth->user_ = ctx->user->accept(this).as<std::string>();
+  return auth;
+}
+
+/**
+ * @return AuthQuery*
+ */
+antlrcpp::Any CypherMainVisitor::visitShowUsersForRole(
+    MemgraphCypher::ShowUsersForRoleContext *ctx) {
+  AuthQuery *auth = storage_.Create<AuthQuery>();
+  auth->action_ = AuthQuery::Action::SHOW_USERS_FOR_ROLE;
+  auth->role_ = ctx->role->accept(this).as<std::string>();
+  return auth;
 }
 
 /**

src/query/frontend/ast/cypher_main_visitor.hpp

@@ -177,6 +177,28 @@ class CypherMainVisitor : public antlropencypher::MemgraphCypherBaseVisitor {
    */
   antlrcpp::Any visitCreate(MemgraphCypher::CreateContext *ctx) override;
 
+  /**
+   * @return std::string
+   */
+  antlrcpp::Any visitUserOrRoleName(
+      MemgraphCypher::UserOrRoleNameContext *ctx) override;
+
+  /**
+   * @return AuthQuery*
+   */
+  antlrcpp::Any visitCreateRole(
+      MemgraphCypher::CreateRoleContext *ctx) override;
+
+  /**
+   * @return AuthQuery*
+   */
+  antlrcpp::Any visitDropRole(MemgraphCypher::DropRoleContext *ctx) override;
+
+  /**
+   * @return AuthQuery*
+   */
+  antlrcpp::Any visitShowRoles(MemgraphCypher::ShowRolesContext *ctx) override;
+
   /**
    * @return CreateIndex*
    */
@@ -184,19 +206,79 @@ class CypherMainVisitor : public antlropencypher::MemgraphCypherBaseVisitor {
       MemgraphCypher::CreateIndexContext *ctx) override;
 
   /**
-   * @return ModifyUser*
+   * @return AuthQuery*
    */
-  antlrcpp::Any visitModifyUser(
+  antlrcpp::Any visitCreateUser(
-      MemgraphCypher::ModifyUserContext *ctx) override;
+      MemgraphCypher::CreateUserContext *ctx) override;
-
-  antlrcpp::Any visitPasswordOption(
-      MemgraphCypher::PasswordOptionContext *ctx) override;
 
   /**
-   * @return DropUser*
+   * @return AuthQuery*
+   */
+  antlrcpp::Any visitSetPassword(
+      MemgraphCypher::SetPasswordContext *ctx) override;
+
+  /**
+   * @return AuthQuery*
    */
   antlrcpp::Any visitDropUser(MemgraphCypher::DropUserContext *ctx) override;
 
+  /**
+   * @return AuthQuery*
+   */
+  antlrcpp::Any visitShowUsers(MemgraphCypher::ShowUsersContext *ctx) override;
+
+  /**
+   * @return AuthQuery*
+   */
+  antlrcpp::Any visitGrantRole(MemgraphCypher::GrantRoleContext *ctx) override;
+
+  /**
+   * @return AuthQuery*
+   */
+  antlrcpp::Any visitRevokeRole(
+      MemgraphCypher::RevokeRoleContext *ctx) override;
+
+  /**
+   * @return AuthQuery*
+   */
+  antlrcpp::Any visitGrantPrivilege(
+      MemgraphCypher::GrantPrivilegeContext *ctx) override;
+
+  /**
+   * @return AuthQuery*
+   */
+  antlrcpp::Any visitDenyPrivilege(
+      MemgraphCypher::DenyPrivilegeContext *ctx) override;
+
+  /**
+   * @return AuthQuery*
+   */
+  antlrcpp::Any visitRevokePrivilege(
+      MemgraphCypher::RevokePrivilegeContext *ctx) override;
+
+  /**
+   * @return AuthQuery::Privilege
+   */
+  antlrcpp::Any visitPrivilege(MemgraphCypher::PrivilegeContext *ctx) override;
+
+  /**
+   * @return AuthQuery*
+   */
+  antlrcpp::Any visitShowGrants(
+      MemgraphCypher::ShowGrantsContext *ctx) override;
+
+  /**
+   * @return AuthQuery*
+   */
+  antlrcpp::Any visitShowRoleForUser(
+      MemgraphCypher::ShowRoleForUserContext *ctx) override;
+
+  /**
+   * @return AuthQuery*
+   */
+  antlrcpp::Any visitShowUsersForRole(
+      MemgraphCypher::ShowUsersForRoleContext *ctx) override;
+
   /**
    * @return CreateStream*
    */

src/query/frontend/opencypher/grammar/MemgraphCypher.g4

@@ -8,23 +8,36 @@ import Cypher ;
 
 memgraphCypherKeyword : cypherKeyword
                       | ALTER
+                      | AUTH
                       | BATCH
                       | BATCHES
                       | DATA
+                      | DENY
                       | DROP
+                      | FOR
+                      | FROM
+                      | GRANT
+                      | GRANTS
+                      | IDENTIFIED
                       | INTERVAL
                       | K_TEST
                       | KAFKA
                       | LOAD
                       | PASSWORD
+                      | PRIVILEGES
+                      | REVOKE
+                      | ROLE
+                      | ROLES
                       | SIZE
                       | START
                       | STOP
                       | STREAM
                       | STREAMS
+                      | TO
                       | TOPIC
                       | TRANSFORM
                       | USER
+                      | USERS
                       ;
 
 symbolicName : UnescapedSymbolicName
@@ -37,19 +50,60 @@ query : regularQuery
       | streamQuery
       ;
 
-authQuery : modifyUser
+authQuery : createRole
+          | dropRole
+          | showRoles
+          | createUser
+          | setPassword
           | dropUser
+          | showUsers
+          | grantRole
+          | revokeRole
+          | grantPrivilege
+          | denyPrivilege
+          | revokePrivilege
+          | showGrants
+          | showRoleForUser
+          | showUsersForRole
           ;
 
-modifyUser : ( CREATE | ALTER ) USER userName=UnescapedSymbolicName
+userOrRoleName : symbolicName ;
-             ( WITH ( modifyUserOption )+ )? ;
 
-modifyUserOption : passwordOption ;
+createRole : CREATE ROLE role=userOrRoleName ;
 
-passwordOption : PASSWORD literal;
+dropRole   : DROP ROLE role=userOrRoleName ;
 
-dropUser : DROP USER userName+=UnescapedSymbolicName
+showRoles  : SHOW ROLES ;
-           ( ',' userName+=UnescapedSymbolicName )* ;
+
+createUser : CREATE USER user=userOrRoleName
+             ( IDENTIFIED BY password=literal )? ;
+
+setPassword : SET PASSWORD FOR user=userOrRoleName TO password=literal;
+
+dropUser : DROP USER user=userOrRoleName ;
+
+showUsers : SHOW USERS ;
+
+grantRole : GRANT ROLE role=userOrRoleName TO user=userOrRoleName ;
+
+revokeRole : REVOKE ROLE role=userOrRoleName FROM user=userOrRoleName ;
+
+grantPrivilege : GRANT privilegeList TO userOrRole=userOrRoleName ;
+
+denyPrivilege : DENY privilegeList TO userOrRole=userOrRoleName ;
+
+revokePrivilege : REVOKE ( ALL PRIVILEGES | privileges=privilegeList ) FROM userOrRole=userOrRoleName ;
+
+privilege : CREATE | DELETE | MATCH | MERGE | SET
+          | AUTH | STREAM ;
+
+privilegeList : privilege ( ',' privilege )* ;
+
+showGrants : SHOW GRANTS FOR userOrRole=userOrRoleName ;
+
+showRoleForUser : SHOW ROLE FOR USER user=userOrRoleName ;
+
+showUsersForRole : SHOW USERS FOR ROLE role=userOrRoleName ;
 
 streamQuery : createStream
             | dropStream

src/query/frontend/opencypher/grammar/MemgraphCypherLexer.g4

@@ -11,20 +11,33 @@ lexer grammar MemgraphCypherLexer ;
 import CypherLexer ;
 
 ALTER          : A L T E R ;
+AUTH           : A U T H ;
 BATCH          : B A T C H ;
 BATCHES        : B A T C H E S ;
 DATA           : D A T A ;
+DENY           : D E N Y ;
 DROP           : D R O P ;
+FOR            : F O R ;
+FROM           : F R O M ;
+GRANT          : G R A N T ;
+GRANTS         : G R A N T S ;
+IDENTIFIED     : I D E N T I F I E D ;
 INTERVAL       : I N T E R V A L ;
 K_TEST         : T E S T ;
 KAFKA          : K A F K A ;
 LOAD           : L O A D ;
 PASSWORD       : P A S S W O R D ;
+PRIVILEGES     : P R I V I L E G E S ;
+REVOKE         : R E V O K E ;
+ROLE           : R O L E ;
+ROLES          : R O L E S ;
 SIZE           : S I Z E ;
 START          : S T A R T ;
 STOP           : S T O P ;
 STREAM         : S T R E A M ;
 STREAMS        : S T R E A M S ;
+TO             : T O ;
 TOPIC          : T O P I C ;
 TRANSFORM      : T R A N S F O R M ;
 USER           : U S E R ;
+USERS          : U S E R S ;

src/query/frontend/semantic/symbol_generator.cpp

@@ -220,9 +220,7 @@ bool SymbolGenerator::PostVisit(Match &) {
 
 bool SymbolGenerator::Visit(CreateIndex &) { return true; }
 
-bool SymbolGenerator::Visit(ModifyUser &) { return true; }
+bool SymbolGenerator::Visit(AuthQuery &) { return true; }
-
-bool SymbolGenerator::Visit(DropUser &) { return true; }
 
 bool SymbolGenerator::Visit(CreateStream &) { return true; }
 

src/query/frontend/semantic/symbol_generator.hpp

@@ -47,8 +47,7 @@ class SymbolGenerator : public HierarchicalTreeVisitor {
   bool PreVisit(Match &) override;
   bool PostVisit(Match &) override;
   bool Visit(CreateIndex &) override;
-  bool Visit(ModifyUser &) override;
+  bool Visit(AuthQuery &) override;
-  bool Visit(DropUser &) override;
   bool Visit(CreateStream &) override;
   bool Visit(DropStream &) override;
   bool Visit(ShowStreams &) override;

src/query/interpret/eval.hpp

@@ -49,8 +49,7 @@ class ExpressionEvaluator : public TreeVisitor<TypedValue> {
   BLOCK_VISIT(Merge);
   BLOCK_VISIT(Unwind);
   BLOCK_VISIT(CreateIndex);
-  BLOCK_VISIT(ModifyUser);
+  BLOCK_VISIT(AuthQuery);
-  BLOCK_VISIT(DropUser);
   BLOCK_VISIT(CreateStream);
   BLOCK_VISIT(DropStream);
   BLOCK_VISIT(ShowStreams);

src/query/plan/cost_estimator.hpp

@@ -185,8 +185,7 @@ class CostEstimator : public HierarchicalLogicalOperatorVisitor {
 
   bool Visit(Once &) override { return true; }
   bool Visit(CreateIndex &) override { return true; }
-  bool Visit(ModifyUser &) override { return true; }
+  bool Visit(AuthHandler &) override { return true; }
-  bool Visit(DropUser &) override { return true; }
   bool Visit(CreateStream &) override { return true; }
   bool Visit(DropStream &) override { return true; }
   bool Visit(ShowStreams &) override { return true; }

src/query/plan/distributed.cpp

@@ -87,8 +87,7 @@ class IndependentSubtreeFinder : public HierarchicalLogicalOperatorVisitor {
   // These don't use any symbols
   bool Visit(Once &) override { return true; }
   bool Visit(CreateIndex &) override { return true; }
-  bool Visit(ModifyUser &) override { return true; }
+  bool Visit(AuthHandler &) override { return true; }
-  bool Visit(DropUser &) override { return true; }
   bool Visit(CreateStream &) override { return true; }
   bool Visit(DropStream &) override { return true; }
   bool Visit(ShowStreams &) override { return true; }
@@ -1344,9 +1343,7 @@ class DistributedPlanner : public HierarchicalLogicalOperatorVisitor {
 
   bool Visit(CreateIndex &) override { return true; }
 
-  bool Visit(ModifyUser &) override { return true; }
+  bool Visit(AuthHandler &) override { return true; }
-
-  bool Visit(DropUser &) override { return true; }
 
   bool Visit(CreateStream &) override { return true; }
 

src/query/plan/operator.cpp

@@ -159,7 +159,7 @@ VertexAccessor &CreateVertexOnWorker(int worker_id, NodeAtom *node_atom,
   int current_worker_id = 0;
   // TODO: Figure out a better solution.
   if (auto *distributed_db =
-      dynamic_cast<database::DistributedGraphDb *>(&dba.db())) {
+          dynamic_cast<database::DistributedGraphDb *>(&dba.db())) {
     current_worker_id = distributed_db->WorkerId();
   } else {
     CHECK(dynamic_cast<database::SingleNode *>(&dba.db()));
@@ -1392,7 +1392,8 @@ class ExpandWeightedShortestPathCursor : public query::plan::Cursor {
     // For the given (edge, vertex, weight, depth) tuple checks if they
     // satisfy the "where" condition. if so, places them in the priority queue.
     auto expand_pair = [this, &evaluator, &frame, &create_state](
-        EdgeAccessor edge, VertexAccessor vertex, double weight, int depth) {
+                           EdgeAccessor edge, VertexAccessor vertex,
+                           double weight, int depth) {
       SwitchAccessor(edge, self_.graph_view_);
       SwitchAccessor(vertex, self_.graph_view_);
 
@@ -3889,130 +3890,120 @@ std::unique_ptr<Cursor> PullRemoteOrderBy::MakeCursor(
   return std::make_unique<PullRemoteOrderByCursor>(*this, db);
 }
 
-ModifyUser::ModifyUser(std::string username, Expression *password,
+AuthHandler::AuthHandler(AuthQuery::Action action, std::string user,
-                       bool is_create)
+                         std::string role, std::string user_or_role,
-    : username_(std::move(username)),
+                         Expression *password,
+                         std::vector<AuthQuery::Privilege> privileges)
+    : action_(action),
+      user_(user),
+      role_(role),
+      user_or_role_(user_or_role),
       password_(password),
-      is_create_(is_create) {}
+      privileges_(privileges) {}
 
-bool ModifyUser::Accept(HierarchicalLogicalOperatorVisitor &visitor) {
+bool AuthHandler::Accept(HierarchicalLogicalOperatorVisitor &visitor) {
   return visitor.Visit(*this);
 }
 
-WITHOUT_SINGLE_INPUT(ModifyUser)
+class AuthHandlerCursor : public Cursor {
-
-class ModifyUserCursor : public Cursor {
  public:
-  ModifyUserCursor(const ModifyUser &self) : self_(self) {}
+  AuthHandlerCursor(const AuthHandler &self) : self_(self) {}
 
   bool Pull(Frame &frame, Context &ctx) override {
     if (ctx.in_explicit_transaction_) {
       throw UserModificationInMulticommandTxException();
     }
+
     ExpressionEvaluator evaluator(frame, &ctx, GraphView::OLD);
-
+    std::experimental::optional<std::string> password;
-    TypedValue password_tv = self_.password()->Accept(evaluator);
+    /* TODO(mferencevic): handle null passwords properly */
-    if (password_tv.type() != TypedValue::Type::String) {
+    if (self_.password()) {
-      throw QueryRuntimeException(fmt::format(
+      auto password_tv = self_.password()->Accept(evaluator);
-          "Password must be a string, not '{}'", password_tv.type()));
+      if (!password_tv.IsString()) {
-    }
+        throw QueryRuntimeException("Password must be a string, not '{}'!",
-
+                                    password_tv.type());
-    // All of the following operations are done with a lock.
-    std::lock_guard<std::mutex> guard(ctx.auth_->WithLock());
-
-    std::experimental::optional<auth::User> user;
-    if (self_.is_create()) {
-      // Create a new user.
-      user = ctx.auth_->AddUser(self_.username());
-      if (!user) {
-        throw QueryRuntimeException(
-            fmt::format("User '{}' already exists!", self_.username()));
       }
-    } else {
+      password = password_tv.ValueString();
-      // Update an existing user.
+    }
-      user = ctx.auth_->GetUser(self_.username());
+
-      if (!user) {
+    auto &auth = *ctx.auth_;
-        throw QueryRuntimeException(
+    std::lock_guard<std::mutex> lock(auth.WithLock());
-            fmt::format("User '{}' doesn't exist!", self_.username()));
+
+    switch (self_.action()) {
+      case AuthQuery::Action::CREATE_USER: {
+        if (!password) {
+          throw QueryRuntimeException(
+              "Password must be provided when creating a user!");
+        }
+        auto user = auth.AddUser(self_.user());
+        if (!user) {
+          throw QueryRuntimeException("User '{}' already exists!",
+                                      self_.user());
+        }
+        user->UpdatePassword(*password);
+        if (!auth.SaveUser(*user)) {
+          throw QueryRuntimeException("Couldn't save user '{}'!", self_.user());
+        }
+        break;
       }
+      case AuthQuery::Action::DROP_USER: {
+        auto user = auth.GetUser(self_.user());
+        if (!user) {
+          throw QueryRuntimeException("User '{}' doesn't exist!", self_.user());
+        }
+        if (!auth.RemoveUser(self_.user())) {
+          throw QueryRuntimeException("Couldn't remove user '{}'!",
+                                      self_.user());
+        }
+        break;
+      }
+      case AuthQuery::Action::SET_PASSWORD: {
+        if (!password) {
+          throw QueryRuntimeException("Password must be provided!");
+        }
+        auto user = auth.GetUser(self_.user());
+        if (!user) {
+          throw QueryRuntimeException("User '{}' doesn't exist!", self_.user());
+        }
+        user->UpdatePassword(*password);
+        if (!auth.SaveUser(*user)) {
+          throw QueryRuntimeException("Couldn't set password for user '{}'!",
+                                      self_.user());
+        }
+        break;
+      }
+      case AuthQuery::Action::CREATE_ROLE:
+      case AuthQuery::Action::DROP_ROLE:
+      case AuthQuery::Action::SHOW_ROLES:
+      case AuthQuery::Action::SHOW_USERS:
+      case AuthQuery::Action::GRANT_ROLE:
+      case AuthQuery::Action::REVOKE_ROLE:
+      case AuthQuery::Action::GRANT_PRIVILEGE:
+      case AuthQuery::Action::DENY_PRIVILEGE:
+      case AuthQuery::Action::REVOKE_PRIVILEGE:
+      case AuthQuery::Action::SHOW_GRANTS:
+      case AuthQuery::Action::SHOW_ROLE_FOR_USER:
+      case AuthQuery::Action::SHOW_USERS_FOR_ROLE:
+        throw utils::NotYetImplemented("user auth");
     }
-
-    // Set the password and save the user.
-    user->UpdatePassword(password_tv.Value<std::string>());
-    if (!ctx.auth_->SaveUser(*user)) {
-      throw QueryRuntimeException(
-          fmt::format("Couldn't save user '{}'!", self_.username()));
-    }
-
     return false;
   }
 
-  void Reset() override {}
+  void Reset() override {
-
+    LOG(FATAL) << "AuthHandler cursor should never be reset";
- private:
-  const ModifyUser &self_;
-};
-
-std::unique_ptr<Cursor> ModifyUser::MakeCursor(
-    database::GraphDbAccessor &) const {
-  return std::make_unique<ModifyUserCursor>(*this);
-}
-
-bool DropUser::Accept(HierarchicalLogicalOperatorVisitor &visitor) {
-  return visitor.Visit(*this);
-}
-
-WITHOUT_SINGLE_INPUT(DropUser)
-
-class DropUserCursor : public Cursor {
- public:
-  DropUserCursor(const DropUser &self) : self_(self) {}
-
-  bool Pull(Frame &, Context &ctx) override {
-    if (ctx.in_explicit_transaction_) {
-      throw UserModificationInMulticommandTxException();
-    }
-
-    // All of the following operations are done with a lock.
-    std::lock_guard<std::mutex> guard(ctx.auth_->WithLock());
-
-    // Check if all users exist.
-    for (const auto &username : self_.usernames()) {
-      auto user = ctx.auth_->GetUser(username);
-      if (!user) {
-        throw QueryRuntimeException(
-            fmt::format("User '{}' doesn't exist!", username));
-      }
-    }
-
-    // Delete all users.
-    std::vector<std::string> failed;
-    for (const auto &username : self_.usernames()) {
-      if (!ctx.auth_->RemoveUser(username)) {
-        failed.push_back(username);
-      }
-    }
-
-    // Check for failures.
-    if (failed.size() > 0) {
-      throw QueryRuntimeException(fmt::format("Couldn't remove users: '{}'!",
-                                              utils::Join(failed, "', '")));
-    }
-
-    return false;
   }
 
-  void Reset() override {}
-
  private:
-  const DropUser &self_;
+  const AuthHandler &self_;
 };
 
-std::unique_ptr<Cursor> DropUser::MakeCursor(
+std::unique_ptr<Cursor> AuthHandler::MakeCursor(
-    database::GraphDbAccessor &) const {
+    database::GraphDbAccessor &db) const {
-  return std::make_unique<DropUserCursor>(*this);
+  return std::make_unique<AuthHandlerCursor>(*this);
 }
 
+WITHOUT_SINGLE_INPUT(AuthHandler)
+
 CreateStream::CreateStream(std::string stream_name, Expression *stream_uri,
                            Expression *stream_topic, Expression *transform_uri,
                            Expression *batch_interval_in_ms,

src/query/plan/operator.lcp

@@ -102,8 +102,7 @@ class PullRemote;
 class Synchronize;
 class Cartesian;
 class PullRemoteOrderBy;
-class ModifyUser;
+class AuthHandler;
-class DropUser;
 class CreateStream;
 class DropStream;
 class ShowStreams;
@@ -122,9 +121,9 @@ using LogicalOperatorCompositeVisitor = ::utils::CompositeVisitor<
     Cartesian, PullRemoteOrderBy>;
 
 using LogicalOperatorLeafVisitor =
-    ::utils::LeafVisitor<Once, CreateIndex, ModifyUser, DropUser,
+    ::utils::LeafVisitor<Once, CreateIndex, AuthHandler, CreateStream,
-                         CreateStream, DropStream, ShowStreams,
+                         DropStream, ShowStreams, StartStopStream,
-                         StartStopStream, StartStopAllStreams, TestStream>;
+                         StartStopAllStreams, TestStream>;
 
 /**
  * @brief Base class for hierarhical visitors of @c LogicalOperator class
@@ -1969,6 +1968,114 @@ and returns true, once.")
    cpp<#)
   (:serialize :capnp))
 
+(lcp:define-class auth-handler (logical-operator)
+  ((action "AuthQuery::Action" :reader t
+           :capnp-init nil
+           :capnp-type "Ast.AuthQuery.Action"
+           :capnp-save (lcp:capnp-save-enum "::query::capnp::AuthQuery::Action"
+                                            "AuthQuery::Action"
+                                            '(create-role drop-role show-roles
+                                              create-user set-password
+                                              drop-user show-users grant-role
+                                              revoke-role grant-privilege
+                                              deny-privilege revoke-privilege
+                                              show-grants show-role-for-user
+                                              show-users-for-role))
+           :capnp-load (lcp:capnp-load-enum "::query::capnp::AuthQuery::Action" 
+                                            "AuthQuery::Action"
+                                            '(create-role drop-role show-roles
+                                              create-user set-password
+                                              drop-user show-users grant-role
+                                              revoke-role grant-privilege
+                                              deny-privilege revoke-privilege
+                                              show-grants show-role-for-user
+                                              show-users-for-role)))
+   (user "std::string" :reader t)
+   (role "std::string" :reader t)
+   (user-or-role "std::string" :reader t)
+   (password "Expression *" :reader t
+             :capnp-type "Ast.Tree" :capnp-init nil
+             :capnp-save #'save-ast-pointer
+             :capnp-load (load-ast-pointer "Expression *"))
+   (privileges "std::vector<AuthQuery::Privilege>" :reader t
+               :capnp-type "List(Ast.AuthQuery.Privilege)"
+               :capnp-save
+                 (lambda (builder member-name)
+                   #>cpp
+                   for (size_t i = 0; i < ${member-name}.size(); ++i) {
+                    switch (privileges_[i]) {
+                      case AuthQuery::Privilege::CREATE:
+                        ${builder}.set(i, query::capnp::AuthQuery::Privilege::CREATE);
+                        break;
+                      case AuthQuery::Privilege::DELETE:
+                        ${builder}.set(i, query::capnp::AuthQuery::Privilege::DELETE);
+                        break;
+                      case AuthQuery::Privilege::MATCH:
+                        ${builder}.set(i, query::capnp::AuthQuery::Privilege::MATCH);
+                        break;
+                      case AuthQuery::Privilege::MERGE:
+                        ${builder}.set(i, query::capnp::AuthQuery::Privilege::MERGE);
+                        break;
+                      case AuthQuery::Privilege::SET:
+                        ${builder}.set(i, query::capnp::AuthQuery::Privilege::SET);
+                        break;
+                      case AuthQuery::Privilege::AUTH:
+                        ${builder}.set(i, query::capnp::AuthQuery::Privilege::AUTH);
+                        break;
+                      case AuthQuery::Privilege::STREAM:
+                        ${builder}.set(i, query::capnp::AuthQuery::Privilege::STREAM);
+                        break;
+                    }
+                  }
+                  cpp<#)
+               :capnp-load
+                 (lambda (reader member-name)
+                   #>cpp
+                   for (auto privilege : ${reader}) {
+                     switch (privilege) {
+                       case query::capnp::AuthQuery::Privilege::CREATE:
+                         ${member-name}.push_back(AuthQuery::Privilege::CREATE);
+                         break;
+                       case query::capnp::AuthQuery::Privilege::DELETE:
+                         ${member-name}.push_back(AuthQuery::Privilege::DELETE);
+                         break;
+                       case query::capnp::AuthQuery::Privilege::MATCH:
+                         ${member-name}.push_back(AuthQuery::Privilege::MATCH);
+                         break;
+                       case query::capnp::AuthQuery::Privilege::MERGE:
+                         ${member-name}.push_back(AuthQuery::Privilege::MERGE);
+                         break;
+                       case query::capnp::AuthQuery::Privilege::SET:
+                         ${member-name}.push_back(AuthQuery::Privilege::SET);
+                         break;
+                       case query::capnp::AuthQuery::Privilege::AUTH:
+                         ${member-name}.push_back(AuthQuery::Privilege::AUTH);
+                         break;
+                       case query::capnp::AuthQuery::Privilege::STREAM:
+                         ${member-name}.push_back(AuthQuery::Privilege::STREAM);
+                         break;
+                     }
+                   }
+                   cpp<#)))
+  (:public
+    #>cpp
+    AuthHandler(AuthQuery::Action action, std::string user, std::string role,
+                std::string user_or_role, Expression * password,
+                std::vector<AuthQuery::Privilege> privileges);
+
+    bool Accept(HierarchicalLogicalOperatorVisitor &visitor) override;
+    std::unique_ptr<Cursor> MakeCursor(database::GraphDbAccessor & db)
+        const override;
+    virtual std::vector<Symbol> ModifiedSymbols(const SymbolTable &)
+        const override { return {}; }
+  
+    bool HasSingleInput() const override;
+    std::shared_ptr<LogicalOperator> input() const override;
+    void set_input(std::shared_ptr<LogicalOperator>) override;
+    cpp<#)
+  (:protected #>cpp AuthHandler() {} cpp<#)
+  (:serialize :capnp))
+
 (lcp:define-class unwind (logical-operator)
   ((input "std::shared_ptr<LogicalOperator>"
           :capnp-save #'save-operator-pointer
@@ -1991,8 +2098,10 @@ Input is optional (unwind can be the first clause in a query).")
        database::GraphDbAccessor &db) const override;
    std::vector<Symbol> ModifiedSymbols(const SymbolTable &) const override;
 
-   bool HasSingleInput() const override { return true; }
+   bool HasSingleInput() const override {
-   std::shared_ptr<LogicalOperator> input() const override { return input_; }
+  return true; }
+   std::shared_ptr<LogicalOperator> input() const override {
+  return input_; }
    void set_input(std::shared_ptr<LogicalOperator> input) override {
      input_ = input;
    }
@@ -2338,70 +2447,6 @@ by having only one result from each worker.")
   (:private #>cpp PullRemoteOrderBy() {} cpp<#)
   (:serialize :capnp))
 
-(lcp:define-class modify-user (logical-operator)
-  ((input "std::shared_ptr<LogicalOperator>"
-          :capnp-save #'save-operator-pointer
-          :capnp-load #'load-operator-pointer)
-   (username "std::string" :reader t)
-   (password "Expression *" :reader t
-             :capnp-type "Ast.Tree"
-             :capnp-init nil
-             :capnp-save #'save-ast-pointer
-             :capnp-load (load-ast-pointer "Expression *"))
-   (is-create :bool :reader t))
-  (:documentation
-   "Operator that creates a new database user or modifies an existing one.")
-  (:public
-   #>cpp
-    ModifyUser(std::string username, Expression *password, bool is_create);
-
-    bool Accept(HierarchicalLogicalOperatorVisitor &visitor) override;
-    std::unique_ptr<Cursor> MakeCursor(
-        database::GraphDbAccessor &db) const override;
-
-    std::vector<Symbol> ModifiedSymbols(const SymbolTable &) const override {
-      return std::vector<Symbol>();
-    }
-
-    bool HasSingleInput() const override;
-    std::shared_ptr<LogicalOperator> input() const override;
-    void set_input(std::shared_ptr<LogicalOperator> input) override;
-   cpp<#)
-  (:private
-   #>cpp
-   ModifyUser() {}
-   cpp<#)
-  (:serialize :capnp))
-
-(lcp:define-class drop-user (logical-operator)
-  ((input "std::shared_ptr<LogicalOperator>"
-          :capnp-save #'save-operator-pointer
-          :capnp-load #'load-operator-pointer)
-   (usernames "std::vector<std::string>" :reader t))
-  (:documentation
-   "Operator that deletes one or more existing database users.")
-  (:public
-   #>cpp
-    DropUser(std::vector<std::string> usernames): usernames_(usernames) {}
-
-    bool Accept(HierarchicalLogicalOperatorVisitor &visitor) override;
-    std::unique_ptr<Cursor> MakeCursor(
-        database::GraphDbAccessor &db) const override;
-
-    std::vector<Symbol> ModifiedSymbols(const SymbolTable &) const override {
-      return std::vector<Symbol>();
-    }
-
-    bool HasSingleInput() const override;
-    std::shared_ptr<LogicalOperator> input() const override;
-    void set_input(std::shared_ptr<LogicalOperator> input) override;
-   cpp<#)
-  (:private
-   #>cpp
-    DropUser() {}
-   cpp<#)
-  (:serialize :capnp))
-
 (lcp:define-class create-stream (logical-operator)
   ((stream-name "std::string" :reader t)
     (stream-uri "Expression *"

src/query/plan/preprocess.hpp

@@ -53,8 +53,7 @@ class UsedSymbolsCollector : public HierarchicalTreeVisitor {
   bool Visit(PrimitiveLiteral &) override { return true; }
   bool Visit(ParameterLookup &) override { return true; }
   bool Visit(query::CreateIndex &) override { return true; }
-  bool Visit(query::ModifyUser &) override { return true; }
+  bool Visit(query::AuthQuery &) override { return true; }
-  bool Visit(query::DropUser &) override { return true; }
   bool Visit(query::CreateStream &) override { return true; }
   bool Visit(query::DropStream &) override { return true; }
   bool Visit(query::ShowStreams &) override { return true; }

src/query/plan/rule_based_planner.cpp

@@ -402,12 +402,7 @@ class ReturnBodyContext : public HierarchicalTreeVisitor {
     return true;
   }
 
-  bool Visit(query::ModifyUser &) override {
+  bool Visit(query::AuthQuery &) override {
-    has_aggregation_.emplace_back(false);
-    return true;
-  }
-
-  bool Visit(query::DropUser &) override {
     has_aggregation_.emplace_back(false);
     return true;
   }

src/query/plan/rule_based_planner.hpp

@@ -182,15 +182,13 @@ class RuleBasedPlanner {
           DCHECK(!input_op) << "Unexpected operator before CreateIndex";
           input_op = std::make_unique<plan::CreateIndex>(
               create_index->label_, create_index->property_);
-        } else if (auto *modify_user =
+        } else if (auto *auth_query =
-                       dynamic_cast<query::ModifyUser *>(clause)) {
+                       dynamic_cast<query::AuthQuery *>(clause)) {
-          DCHECK(!input_op) << "Unexpected operator before ModifyUser";
+          DCHECK(!input_op) << "Unexpected operator before AuthQuery";
-          input_op = std::make_unique<plan::ModifyUser>(
+          input_op = std::make_unique<plan::AuthHandler>(
-              modify_user->username_, modify_user->password_,
+              auth_query->action_, auth_query->user_, auth_query->role_,
-              modify_user->is_create_);
+              auth_query->user_or_role_, auth_query->password_,
-        } else if (auto *drop_user = dynamic_cast<query::DropUser *>(clause)) {
+              auth_query->privileges_);
-          DCHECK(!input_op) << "Unexpected operator before DropUser";
-          input_op = std::make_unique<plan::DropUser>(drop_user->usernames_);
         } else if (auto *create_stream =
                        dynamic_cast<query::CreateStream *>(clause)) {
           DCHECK(!input_op) << "Unexpected operator before CreateStream";

tests/manual/query_planner.cpp

@@ -514,13 +514,8 @@ class PlanPrinter : public query::plan::HierarchicalLogicalOperatorVisitor {
     return true;
   }
 
-  bool Visit(query::plan::ModifyUser &op) override {
+  bool Visit(query::plan::AuthHandler &op) override {
-    WithPrintLn([](auto &out) { out << "* ModifyUser "; });
+    WithPrintLn([](auto &out) { out << "* AuthHandler"; });
-    return true;
-  }
-
-  bool Visit(query::plan::DropUser &op) override {
-    WithPrintLn([](auto &out) { out << "* DropUser"; });
     return true;
   }
 

tests/unit/cypher_main_visitor.cpp

@@ -1866,72 +1866,203 @@ TYPED_TEST(CypherMainVisitorTest, UnionAll) {
   ASSERT_FALSE(return_clause->body_.distinct);
 }
 
-TYPED_TEST(CypherMainVisitorTest, ModifyUser) {
+template <typename AstGeneratorT>
-  auto check_modify_user = [](std::string input, std::string username,
+void check_auth_query(std::string input, AuthQuery::Action action,
-                              std::experimental::optional<TypedValue> password,
+                      std::string user, std::string role,
-                              bool is_create) {
+                      std::string user_or_role,
-    TypeParam ast_generator(input);
+                      std::experimental::optional<TypedValue> password,
-    auto *query = ast_generator.query_;
+                      std::vector<AuthQuery::Privilege> privileges) {
-    ASSERT_TRUE(query->single_query_);
+  AstGeneratorT ast_generator(input);
-    auto *single_query = query->single_query_;
+  auto *query = ast_generator.query_;
-    ASSERT_EQ(single_query->clauses_.size(), 1U);
+  ASSERT_TRUE(query->single_query_ &&
-    auto *create_user = dynamic_cast<ModifyUser *>(single_query->clauses_[0]);
+              query->single_query_->clauses_.size() == 1U);
-    ASSERT_TRUE(create_user);
+  auto auth_query =
-    EXPECT_EQ(create_user->username_, username);
+      dynamic_cast<AuthQuery *>(query->single_query_->clauses_[0]);
-    if (password) {
+  EXPECT_EQ(auth_query->action_, action);
-      ASSERT_NE(create_user->password_, nullptr);
+  EXPECT_EQ(auth_query->user_, user);
-      CheckLiteral(ast_generator.context_, create_user->password_, *password);
+  EXPECT_EQ(auth_query->role_, role);
-    } else {
+  EXPECT_EQ(auth_query->user_or_role_, user_or_role);
-      EXPECT_EQ(create_user->password_, nullptr);
+  ASSERT_EQ(static_cast<bool>(auth_query->password_),
-    }
+            static_cast<bool>(password));
-    EXPECT_EQ(create_user->is_create_, is_create);
+  if (password) {
-  };
+    CheckLiteral(ast_generator.context_, auth_query->password_, *password);
+  }
+  EXPECT_EQ(auth_query->privileges_, privileges);
+}
 
-  check_modify_user("CreaTE UsEr dominik", "dominik",
+TYPED_TEST(CypherMainVisitorTest, UserOrRoleName) {
-                    std::experimental::nullopt, true);
+  ASSERT_THROW(TypeParam("CREATE ROLE `us|er`"), SyntaxException);
-  check_modify_user("CreaTE UsEr dominik WIth PaSSWORD 'spomenik'", "dominik",
+  ASSERT_THROW(TypeParam("CREATE ROLE `us er`"), SyntaxException);
-                    "spomenik", true);
+  check_auth_query<TypeParam>("CREATE ROLE `user`",
-  check_modify_user("CreaTE UsEr dominik WIth PaSSWORD NULL", "dominik",
+                              AuthQuery::Action::CREATE_ROLE, "", "user", "",
-                    TypedValue::Null, true);
+                              {}, {});
-  check_modify_user("AlTeR UsEr dominik", "dominik", std::experimental::nullopt,
+  check_auth_query<TypeParam>("CREATE ROLE us___er",
-                    false);
+                              AuthQuery::Action::CREATE_ROLE, "", "us___er", "",
-  check_modify_user("ALtEr UsEr dominik", "dominik", std::experimental::nullopt,
+                              {}, {});
-                    false);
+  check_auth_query<TypeParam>("CREATE ROLE `us+er`",
-  check_modify_user("ALtEr UsEr dominik WIth PaSSWORD 'spomenik'", "dominik",
+                              AuthQuery::Action::CREATE_ROLE, "", "us+er", "",
-                    "spomenik", false);
+                              {}, {});
-  check_modify_user("ALtEr UsEr dominik WIth PaSSWORD NULL", "dominik",
+}
-                    TypedValue::Null, false);
+
-  EXPECT_THROW(
+TYPED_TEST(CypherMainVisitorTest, CreateRole) {
-      check_modify_user(
+  ASSERT_THROW(TypeParam("CREATE ROLE"), SyntaxException);
-          "CreaTE UsEr dominik WIth PaSSWORD 'spomenik' PaSSwoRD 'u muzeju'",
+  check_auth_query<TypeParam>("CREATE ROLE rola",
-          "dominik", "spomenik", true),
+                              AuthQuery::Action::CREATE_ROLE, "", "rola", "",
-      QueryException);
+                              {}, {});
-  EXPECT_THROW(check_modify_user("CreaTE UsEr dominik WIth PaSSWORD 12345",
+  ASSERT_THROW(TypeParam("CREATE ROLE lagano rolamo"), SyntaxException);
-                                 "dominik", "spomenik", true),
+}
+
+TYPED_TEST(CypherMainVisitorTest, DropRole) {
+  ASSERT_THROW(TypeParam("DROP ROLE"), SyntaxException);
+  check_auth_query<TypeParam>("DROP ROLE rola", AuthQuery::Action::DROP_ROLE,
+                              "", "rola", "", {}, {});
+  ASSERT_THROW(TypeParam("DROP ROLE lagano rolamo"), SyntaxException);
+}
+
+TYPED_TEST(CypherMainVisitorTest, ShowRoles) {
+  ASSERT_THROW(TypeParam("SHOW ROLES ROLES"), SyntaxException);
+  check_auth_query<TypeParam>("SHOW ROLES", AuthQuery::Action::SHOW_ROLES, "",
+                              "", "", {}, {});
+}
+
+TYPED_TEST(CypherMainVisitorTest, CreateUser) {
+  ASSERT_THROW(TypeParam("CREATE USER"), SyntaxException);
+  ASSERT_THROW(TypeParam("CREATE USER 123"), SyntaxException);
+  check_auth_query<TypeParam>("CREATE USER user",
+                              AuthQuery::Action::CREATE_USER, "user", "", "",
+                              {}, {});
+  check_auth_query<TypeParam>("CREATE USER user IDENTIFIED BY 'password'",
+                              AuthQuery::Action::CREATE_USER, "user", "", "",
+                              "password", {});
+  check_auth_query<TypeParam>("CREATE USER user IDENTIFIED BY ''",
+                              AuthQuery::Action::CREATE_USER, "user", "", "",
+                              "", {});
+  check_auth_query<TypeParam>("CREATE USER user IDENTIFIED BY null",
+                              AuthQuery::Action::CREATE_USER, "user", "", "",
+                              TypedValue::Null, {});
+  ASSERT_THROW(TypeParam("CRATE USER user IDENTIFIED BY password"),
                SyntaxException);
+  ASSERT_THROW(TypeParam("CREATE USER user IDENTIFIED BY 5"), SyntaxException);
+  ASSERT_THROW(TypeParam("CREATE USER user IDENTIFIED BY "), SyntaxException);
+}
+
+TYPED_TEST(CypherMainVisitorTest, SetPassword) {
+  ASSERT_THROW(TypeParam("SET PASSWORD FOR"), SyntaxException);
+  ASSERT_THROW(TypeParam("SET PASSWORD FOR user "), SyntaxException);
+  check_auth_query<TypeParam>("SET PASSWORD FOR user TO null",
+                              AuthQuery::Action::SET_PASSWORD, "user", "", "",
+                              TypedValue::Null, {});
+  check_auth_query<TypeParam>("SET PASSWORD FOR user TO 'password'",
+                              AuthQuery::Action::SET_PASSWORD, "user", "", "",
+                              "password", {});
+  ASSERT_THROW(TypeParam("SET PASSWORD FOR user To 5"), SyntaxException);
 }
 
 TYPED_TEST(CypherMainVisitorTest, DropUser) {
-  auto check_drop_user = [](std::string input,
+  ASSERT_THROW(TypeParam("DROP USER"), SyntaxException);
-                            const std::vector<std::string> &usernames) {
+  check_auth_query<TypeParam>("DROP USER user", AuthQuery::Action::DROP_USER,
-    TypeParam ast_generator(input);
+                              "user", "", "", {}, {});
-    auto *query = ast_generator.query_;
+  ASSERT_THROW(TypeParam("DROP USER lagano rolamo"), SyntaxException);
-    ASSERT_TRUE(query->single_query_);
+}
-    auto *single_query = query->single_query_;
-    ASSERT_EQ(single_query->clauses_.size(), 1U);
-    auto *drop_user = dynamic_cast<DropUser *>(single_query->clauses_[0]);
-    ASSERT_TRUE(drop_user);
-    EXPECT_EQ(drop_user->usernames_, usernames);
-  };
 
-  EXPECT_THROW(check_drop_user("DrOp USER", {}), SyntaxException);
+TYPED_TEST(CypherMainVisitorTest, ShowUsers) {
-  check_drop_user("DrOP UsEr dominik", {"dominik"});
+  ASSERT_THROW(TypeParam("SHOW USERS ROLES"), SyntaxException);
-  check_drop_user("DrOP USER dominik  ,   spomenik", {"dominik", "spomenik"});
+  check_auth_query<TypeParam>("SHOW USERS", AuthQuery::Action::SHOW_USERS, "",
-  EXPECT_THROW(
+                              "", "", {}, {});
-      check_drop_user("DrOP USER dominik, , spomenik", {"dominik", "spomenik"}),
+}
-      SyntaxException);
+
-  check_drop_user("DrOP USER dominik , spomenik    ,   jackie, jackie , johnny",
+TYPED_TEST(CypherMainVisitorTest, GrantRole) {
-                  {"dominik", "spomenik", "jackie", "jackie", "johnny"});
+  ASSERT_THROW(TypeParam("GRANT ROLE"), SyntaxException);
+  ASSERT_THROW(TypeParam("GRANT ROLE role"), SyntaxException);
+  ASSERT_THROW(TypeParam("GRANT ROLE role TO"), SyntaxException);
+  ASSERT_THROW(TypeParam("GRANT ROLE TO user"), SyntaxException);
+  check_auth_query<TypeParam>("GRANT ROLE role TO user",
+                              AuthQuery::Action::GRANT_ROLE, "user", "role", "",
+                              {}, {});
+}
+
+TYPED_TEST(CypherMainVisitorTest, RevokeRole) {
+  ASSERT_THROW(TypeParam("REVOKE ROLE"), SyntaxException);
+  ASSERT_THROW(TypeParam("REVOKE ROLE role"), SyntaxException);
+  ASSERT_THROW(TypeParam("REVOKE ROLE role FROM"), SyntaxException);
+  ASSERT_THROW(TypeParam("REVOKE ROLE FROM user"), SyntaxException);
+  check_auth_query<TypeParam>("REVOKE ROLE role FROM user",
+                              AuthQuery::Action::REVOKE_ROLE, "user", "role",
+                              "", {}, {});
+}
+
+TYPED_TEST(CypherMainVisitorTest, GrantPrivilege) {
+  ASSERT_THROW(TypeParam("GRANT"), SyntaxException);
+  ASSERT_THROW(TypeParam("GRANT TO user"), SyntaxException);
+  ASSERT_THROW(TypeParam("GRANT BLABLA TO user"), SyntaxException);
+  ASSERT_THROW(TypeParam("GRANT MATCH, TO user"), SyntaxException);
+  ASSERT_THROW(TypeParam("GRANT MATCH, BLABLA TO user"), SyntaxException);
+  check_auth_query<TypeParam>("GRANT MATCH TO user",
+                              AuthQuery::Action::GRANT_PRIVILEGE, "", "",
+                              "user", {}, {AuthQuery::Privilege::MATCH});
+  check_auth_query<TypeParam>(
+      "GRANT MATCH, AUTH TO user", AuthQuery::Action::GRANT_PRIVILEGE, "", "",
+      "user", {}, {AuthQuery::Privilege::MATCH, AuthQuery::Privilege::AUTH});
+}
+
+TYPED_TEST(CypherMainVisitorTest, DenyPrivilege) {
+  ASSERT_THROW(TypeParam("DENY"), SyntaxException);
+  ASSERT_THROW(TypeParam("DENY TO user"), SyntaxException);
+  ASSERT_THROW(TypeParam("DENY BLABLA TO user"), SyntaxException);
+  ASSERT_THROW(TypeParam("DENY MATCH, TO user"), SyntaxException);
+  ASSERT_THROW(TypeParam("DENY MATCH, BLABLA TO user"), SyntaxException);
+  check_auth_query<TypeParam>("DENY MATCH TO user",
+                              AuthQuery::Action::DENY_PRIVILEGE, "", "",
+                              "user", {}, {AuthQuery::Privilege::MATCH});
+  check_auth_query<TypeParam>(
+      "DENY MATCH, AUTH TO user", AuthQuery::Action::DENY_PRIVILEGE, "", "",
+      "user", {}, {AuthQuery::Privilege::MATCH, AuthQuery::Privilege::AUTH});
+}
+
+TYPED_TEST(CypherMainVisitorTest, RevokePrivilege) {
+  ASSERT_THROW(TypeParam("REVOKE"), SyntaxException);
+  ASSERT_THROW(TypeParam("REVOKE FROM user"), SyntaxException);
+  ASSERT_THROW(TypeParam("REVOKE BLABLA FROM user"), SyntaxException);
+  ASSERT_THROW(TypeParam("REVOKE MATCH, FROM user"), SyntaxException);
+  ASSERT_THROW(TypeParam("REVOKE MATCH, BLABLA FROM user"), SyntaxException);
+  check_auth_query<TypeParam>("REVOKE MATCH FROM user",
+                              AuthQuery::Action::REVOKE_PRIVILEGE, "", "",
+                              "user", {}, {AuthQuery::Privilege::MATCH});
+  check_auth_query<TypeParam>(
+      "REVOKE MATCH, AUTH FROM user", AuthQuery::Action::REVOKE_PRIVILEGE, "",
+      "", "user", {},
+      {AuthQuery::Privilege::MATCH, AuthQuery::Privilege::AUTH});
+  check_auth_query<TypeParam>(
+      "REVOKE ALL PRIVILEGES FROM user", AuthQuery::Action::REVOKE_PRIVILEGE,
+      "", "", "user", {},
+      {AuthQuery::Privilege::CREATE, AuthQuery::Privilege::DELETE,
+       AuthQuery::Privilege::MATCH, AuthQuery::Privilege::MERGE,
+       AuthQuery::Privilege::SET, AuthQuery::Privilege::AUTH,
+       AuthQuery::Privilege::STREAM});
+}
+
+TYPED_TEST(CypherMainVisitorTest, ShowGrants) {
+  ASSERT_THROW(TypeParam("SHOW GRANTS FOR"), SyntaxException);
+  check_auth_query<TypeParam>("SHOW GRANTS FOR user",
+                              AuthQuery::Action::SHOW_GRANTS, "", "", "user",
+                              {}, {});
+  ASSERT_THROW(TypeParam("SHOW GRANTS FOR user1, user2"), SyntaxException);
+}
+
+TYPED_TEST(CypherMainVisitorTest, ShowRoleForUser) {
+  ASSERT_THROW(TypeParam("SHOW ROLE FOR USER"), SyntaxException);
+  check_auth_query<TypeParam>("SHOW ROLE FOR USER user",
+                              AuthQuery::Action::SHOW_ROLE_FOR_USER, "user", "",
+                              "", {}, {});
+  ASSERT_THROW(TypeParam("SHOW ROLE FOR USER user1, user2"), SyntaxException);
+}
+
+TYPED_TEST(CypherMainVisitorTest, ShowUsersForRole) {
+  ASSERT_THROW(TypeParam("SHOW USERS FOR ROLE"), SyntaxException);
+  check_auth_query<TypeParam>("SHOW USERS FOR ROLE role",
+                              AuthQuery::Action::SHOW_USERS_FOR_ROLE, "",
+                              "role", "", {}, {});
+  ASSERT_THROW(TypeParam("SHOW USERS FOR ROLE role1, role2"), SyntaxException);
 }
 
 TYPED_TEST(CypherMainVisitorTest, CreateStream) {

tests/unit/query_common.hpp

@@ -574,10 +574,9 @@ auto GetMerge(AstStorage &storage, Pattern *pattern, OnMatch on_match,
 #define EXTRACT(variable, list, expr)                                         \
   storage.Create<query::Extract>(storage.Create<query::Identifier>(variable), \
                                  list, expr)
-#define CREATE_USER(username, password) \
+#define AUTH_QUERY(action, user, role, user_or_role, password, privileges)   \
-  storage.Create<query::ModifyUser>((username), LITERAL(password), true)
+  storage.Create<query::AuthQuery>((action), (user), (role), (user_or_role), \
-#define ALTER_USER(username, password) \
+                                   LITERAL(password), (privileges))
-  storage.Create<query::ModifyUser>((username), LITERAL(password), false)
 #define DROP_USER(usernames) storage.Create<query::DropUser>((usernames))
 #define CREATE_STREAM(stream_name, stream_uri, stream_topic, transform_uri, \
                       batch_interval, batch_size)                           \

tests/unit/query_planner.cpp

@@ -132,8 +132,7 @@ class PlanChecker : public HierarchicalLogicalOperatorVisitor {
 
   PRE_VISIT(PullRemoteOrderBy);
 
-  VISIT(ModifyUser);
+  VISIT(AuthHandler);
-  VISIT(DropUser);
 
   VISIT(CreateStream);
   VISIT(DropStream);
@@ -377,6 +376,37 @@ class ExpectScanAllByLabelPropertyRange
   std::experimental::optional<Bound> upper_bound_;
 };
 
+class ExpectAuthHandler : public OpChecker<AuthHandler> {
+ public:
+  ExpectAuthHandler(query::AuthQuery::Action action, std::string user,
+                    std::string role, std::string user_or_role,
+                    query::Expression *password,
+                    std::vector<query::AuthQuery::Privilege> privileges)
+      : action_(action),
+        user_(user),
+        role_(role),
+        user_or_role_(user_or_role),
+        password_(password),
+        privileges_(privileges) {}
+
+  void ExpectOp(AuthHandler &auth_handler, const SymbolTable &) override {
+    EXPECT_EQ(auth_handler.action(), action_);
+    EXPECT_EQ(auth_handler.user(), user_);
+    EXPECT_EQ(auth_handler.role(), role_);
+    EXPECT_EQ(auth_handler.user_or_role(), user_or_role_);
+    EXPECT_TRUE(auth_handler.password());
+    EXPECT_EQ(auth_handler.privileges(), privileges_);
+  }
+
+ private:
+  query::AuthQuery::Action action_;
+  std::string user_;
+  std::string role_;
+  std::string user_or_role_;
+  query::Expression *password_{nullptr};
+  std::vector<query::AuthQuery::Privilege> privileges_;
+};
+
 class ExpectCreateIndex : public OpChecker<CreateIndex> {
  public:
   ExpectCreateIndex(storage::Label label, storage::Property property)
@@ -623,36 +653,6 @@ class Planner {
   std::unique_ptr<LogicalOperator> plan_;
 };
 
-class ExpectModifyUser : public OpChecker<ModifyUser> {
- public:
-  ExpectModifyUser(std::string username, bool is_create)
-      : username_(username), is_create_(is_create) {}
-
-  void ExpectOp(ModifyUser &modify_user, const SymbolTable &) override {
-    EXPECT_EQ(username_, modify_user.username());
-    // TODO(mtomic): proper password verification
-    EXPECT_NE(dynamic_cast<query::Expression *>(modify_user.password()),
-              nullptr);
-    EXPECT_EQ(is_create_, modify_user.is_create());
-  }
-
- private:
-  std::string username_;
-  bool is_create_;
-};
-
-class ExpectDropUser : public OpChecker<DropUser> {
- public:
-  ExpectDropUser(std::vector<std::string> usernames) : usernames_(usernames) {}
-
-  void ExpectOp(DropUser &drop_user, const SymbolTable &) override {
-    EXPECT_EQ(usernames_, drop_user.usernames());
-  }
-
- private:
-  std::vector<std::string> usernames_;
-};
-
 void SavePlan(const LogicalOperator &plan, ::capnp::MessageBuilder *message) {
   auto builder = message->initRoot<query::plan::capnp::LogicalOperator>();
   LogicalOperator::SaveHelper helper;
@@ -2076,8 +2076,9 @@ TYPED_TEST(TestPlanner, WhereIndexedLabelPropertyRange) {
   AstStorage storage;
   auto lit_42 = LITERAL(42);
   auto n_prop = PROPERTY_LOOKUP("n", property);
-  auto check_planned_range = [&label, &property, &dba](
+  auto check_planned_range = [&label, &property, &dba](const auto &rel_expr,
-      const auto &rel_expr, auto lower_bound, auto upper_bound) {
+                                                       auto lower_bound,
+                                                       auto upper_bound) {
     // Shadow the first storage, so that the query is created in this one.
     AstStorage storage;
     QUERY(SINGLE_QUERY(MATCH(PATTERN(NODE("n", label))), WHERE(rel_expr),
@@ -2318,36 +2319,25 @@ TYPED_TEST(TestPlanner, ReturnAsteriskOmitsLambdaSymbols) {
   }
 }
 
-TYPED_TEST(TestPlanner, ModifyUser) {
+TYPED_TEST(TestPlanner, AuthQuery) {
-  {
+  // Check if everything is properly forwarded from ast node to the operator
-    // Test CREATE USER user WITH PASSWORD 'password'
+  FakeDbAccessor dba;
-    FakeDbAccessor dba;
-    AstStorage storage;
-    QUERY(SINGLE_QUERY(CREATE_USER("user", "password")));
-    CheckPlan<TypeParam>(storage, ExpectModifyUser("user", true));
-    auto expected =
-        ExpectDistributed(MakeCheckers(ExpectModifyUser("user", true)));
-    CheckDistributedPlan<TypeParam>(storage, expected);
-  }
-  {
-    // Test ALTER USER user WITH PASSWORD 'password'
-    FakeDbAccessor dba;
-    AstStorage storage;
-    QUERY(SINGLE_QUERY(ALTER_USER("user", "password")));
-    CheckPlan<TypeParam>(storage, ExpectModifyUser("user", false));
-    auto expected =
-        ExpectDistributed(MakeCheckers(ExpectModifyUser("user", false)));
-    CheckDistributedPlan<TypeParam>(storage, expected);
-  }
-}
-
-TYPED_TEST(TestPlanner, DropUser) {
-  // Test DROP USER user1, user2, user3
   AstStorage storage;
-  std::vector<std::string> usernames({"user1", "user2", "user3"});
+  QUERY(SINGLE_QUERY(AUTH_QUERY(query::AuthQuery::Action::DROP_ROLE, "user",
-  QUERY(SINGLE_QUERY(DROP_USER(usernames)));
+                                "role", "user_or_role", LITERAL("password"),
-  CheckPlan<TypeParam>(storage, ExpectDropUser(usernames));
+                                std::vector<query::AuthQuery::Privilege>(
-  auto expected = ExpectDistributed(MakeCheckers(ExpectDropUser(usernames)));
+                                    {query::AuthQuery::Privilege::MATCH,
+                                     query::AuthQuery::Privilege::AUTH}))));
+  CheckPlan<TypeParam>(
+      storage, ExpectAuthHandler(query::AuthQuery::Action::DROP_ROLE, "user",
+                                 "role", "user_or_role", LITERAL("password"),
+                                 {query::AuthQuery::Privilege::MATCH,
+                                  query::AuthQuery::Privilege::AUTH}));
+  auto expected = ExpectDistributed(MakeCheckers(
+      ExpectAuthHandler(query::AuthQuery::Action::DROP_ROLE, "user", "role",
+                        "user_or_role", LITERAL("password"),
+                        {query::AuthQuery::Privilege::MATCH,
+                         query::AuthQuery::Privilege::AUTH})));
   CheckDistributedPlan<TypeParam>(storage, expected);
 }