gristlabs_grist-core/app/server/lib/GranularAccess.ts
Paul Fitzpatrick 3d3fe92bd0 (core) support access control on columns
Summary: Adds a granular access clause for columns. Permissions can be specified for a set of columns within a table. Permissions accumulate over clauses, in a way that is intended as a placeholder pending final design.

Test Plan: Added tests. Tested manually that updates to private columns are not sent to people who don't have access to them. There are a lot of extra tests needed and TODOs to be paid down after this experimental phase.

Reviewers: dsagal

Reviewed By: dsagal

Differential Revision: https://phab.getgrist.com/D2651
2020-11-03 19:08:44 -05:00

725 lines
28 KiB
TypeScript

import { ActionGroup } from 'app/common/ActionGroup';
import { createEmptyActionSummary } from 'app/common/ActionSummary';
import { Query } from 'app/common/ActiveDocAPI';
import { BulkColValues, CellValue, ColValues, DocAction, TableDataAction, UserAction } from 'app/common/DocActions';
import { DocData } from 'app/common/DocData';
import { ErrorWithCode } from 'app/common/ErrorWithCode';
import { AccessPermissions, decodeClause, GranularAccessCharacteristicsClause,
GranularAccessClause, GranularAccessColumnClause, MatchSpec } from 'app/common/GranularAccessClause';
import { canView } from 'app/common/roles';
import { TableData } from 'app/common/TableData';
import { Permissions } from 'app/gen-server/lib/Permissions';
import { getDocSessionAccess, getDocSessionUser, OptDocSession } from 'app/server/lib/DocSession';
import * as log from 'app/server/lib/log';
import pullAt = require('lodash/pullAt');
import cloneDeep = require('lodash/cloneDeep');
// Actions that may be allowed for a user with nuanced access to a document, depending
// on what table they refer to.
const ACTION_WITH_TABLE_ID = new Set(['AddRecord', 'BulkAddRecord', 'UpdateRecord', 'BulkUpdateRecord',
'RemoveRecord', 'BulkRemoveRecord',
'ReplaceTableData', 'TableData',
]);
// Actions that won't be allowed (yet) for a user with nuanced access to a document.
// A few may be innocuous, but generally I've put them in this list if there are problems
// tracking down what table the refer to, or they could allow creation/modification of a
// formula.
const SPECIAL_ACTIONS = new Set(['InitNewDoc',
'EvalCode',
'SetDisplayFormula',
'CreateViewSection',
'UpdateSummaryViewSection',
'DetachSummaryViewSection',
'GenImporterView',
'TransformAndFinishImport',
'AddColumn', 'RemoveColumn', 'RenameColumn', 'ModifyColumn',
'AddTable', 'RemoveTable', 'RenameTable',
'AddView',
'CopyFromColumn',
'AddHiddenColumn',
'RemoveViewSection'
]);
// Odd-ball actions marked as deprecated or which seem unlikely to be used.
const SURPRISING_ACTIONS = new Set(['AddUser',
'RemoveUser',
'AddInstance',
'RemoveInstance',
'RemoveView',
'AddViewSection',
]);
// Actions we'll allow unconditionally for now.
const OK_ACTIONS = new Set(['Calculate', 'AddEmptyTable']);
/**
*
* Manage granular access to a document. This allows nuances other than the coarse
* owners/editors/viewers distinctions. As a placeholder for a future representation,
* nuances are stored in the _grist_ACLResources table.
*
*/
export class GranularAccess {
private _resources: TableData;
private _clauses = new Array<GranularAccessClause>();
// Cache any tables that we need to look-up for access control decisions.
// This is an unoptimized implementation that is adequate if the tables
// are not large and don't change all that often.
private _characteristicTables = new Map<string, CharacteristicTable>();
public constructor(private _docData: DocData, private _fetchQuery: (query: Query) => Promise<TableDataAction>) {
}
/**
* Update granular access from DocData.
*/
public async update() {
this._resources = this._docData.getTable('_grist_ACLResources')!;
this._clauses.length = 0;
for (const res of this._resources.getRecords()) {
const clause = decodeClause(String(res.colIds));
if (clause) { this._clauses.push(clause); }
}
if (this._clauses.length > 0) {
// TODO: optimize this.
await this._updateCharacteristicTables();
}
}
/**
* Check whether user can carry out query.
*/
public hasQueryAccess(docSession: OptDocSession, query: Query) {
return this.hasTableAccess(docSession, query.tableId);
}
/**
* Check whether user has access to table.
*/
public hasTableAccess(docSession: OptDocSession, tableId: string) {
return Boolean(this.getTableAccess(docSession, tableId).permission & Permissions.VIEW);
}
/**
* Filter DocActions to be sent to a client.
*/
public filterOutgoingDocActions(docSession: OptDocSession, docActions: DocAction[]): DocAction[] {
return docActions.map(action => this.pruneOutgoingDocAction(docSession, action))
.filter(docActions => docActions !== null) as DocAction[];
}
/**
* Filter an ActionGroup to be sent to a client.
*/
public filterActionGroup(docSession: OptDocSession, actionGroup: ActionGroup): ActionGroup {
if (!this.allowActionGroup(docSession, actionGroup)) { return actionGroup; }
// For now, if there's any nuance at all, suppress the summary and description.
// TODO: create an empty action summary, to be sure not to leak anything important.
const result: ActionGroup = { ...actionGroup };
result.actionSummary = createEmptyActionSummary();
result.desc = '';
return result;
}
/**
* Check whether an ActionGroup can be sent to the client. TODO: in future, we'll want
* to filter acceptible parts of ActionGroup, rather than denying entirely.
*/
public allowActionGroup(docSession: OptDocSession, actionGroup: ActionGroup): boolean {
return this.canReadEverything(docSession);
}
/**
* Check if user can apply a list of actions.
*/
public canApplyUserActions(docSession: OptDocSession, actions: UserAction[]): boolean {
return actions.every(action => this.canApplyUserAction(docSession, action));
}
/**
* Check if user can apply a given action to the document.
*/
public canApplyUserAction(docSession: OptDocSession, a: UserAction|DocAction): boolean {
const name = a[0] as string;
if (OK_ACTIONS.has(name)) { return true; }
if (SPECIAL_ACTIONS.has(name)) {
return !this.hasNuancedAccess(docSession);
}
if (SURPRISING_ACTIONS.has(name)) {
return this.hasFullAccess(docSession);
}
const isTableAction = ACTION_WITH_TABLE_ID.has(name);
if (a[0] === 'ApplyUndoActions') {
return this.canApplyUserActions(docSession, a[1] as UserAction[]);
} else if (a[0] === 'ApplyDocActions') {
return this.canApplyUserActions(docSession, a[1] as UserAction[]);
} else if (isTableAction) {
const tableId = a[1] as string;
// If there are any access control nuances, deny _grist_* tables.
// TODO: this is very crude, loosen this up appropriately.
if (tableId.startsWith('_grist_')) {
return !this.hasNuancedAccess(docSession);
}
const tableAccess = this.getTableAccess(docSession, tableId);
// For now, if there are any row restrictions, forbid editing.
// To allow editing, we'll need something that has access to full row,
// e.g. data engine (and then an equivalent for ondemand tables), or
// to fetch rows at this point.
if (tableAccess.rowPermissionFunctions.length > 0) { return false; }
return Boolean(tableAccess.permission & Permissions.VIEW);
}
return false;
}
/**
* Cut out any rows/columns not accessible to the user. May throw a NEED_RELOAD
* exception if the information needed to achieve the desired pruning is not available.
* Returns null if the action is entirely pruned. The action passed in is never modified.
*/
public pruneOutgoingDocAction(docSession: OptDocSession, a: DocAction): DocAction|null {
const tableId = a[1] as string;
const tableAccess = this.getTableAccess(docSession, tableId);
if (!(tableAccess.permission & Permissions.VIEW)) { return null; }
if (tableAccess.rowPermissionFunctions.length > 0) {
// For now, trigger a reload, since we don't have the
// information we need to filter rows. Reloads would be very
// annoying if user is working on something, but at least data
// won't be stale. TODO: improve!
throw new ErrorWithCode('NEED_RELOAD', 'document needs reload');
}
if (tableAccess.columnPermissions.size > 0) {
if (a[0] === 'RemoveRecord' || a[0] === 'BulkRemoveRecord') {
return a;
} else if (a[0] === 'AddRecord' || a[0] === 'BulkAddRecord' || a[0] == 'UpdateRecord' ||
a[0] === 'BulkUpdateRecord' || a[0] === 'ReplaceTableData' || a[0] === 'TableData') {
const na = cloneDeep(a);
this.filterColumns(na[3], tableAccess);
if (Object.keys(na[3]).length === 0) { return null; }
return na;
} else if (a[0] === 'AddColumn' || a[0] === 'RemoveColumn' || a[0] === 'RenameColumn' ||
a[0] === 'ModifyColumn') {
const na = cloneDeep(a);
const perms = tableAccess.columnPermissions.get(na[2]);
if (perms && (perms.forbidden & Permissions.VIEW)) { return null; }
throw new ErrorWithCode('NEED_RELOAD', 'document needs reload');
} else {
// Remaining cases of AddTable, RemoveTable, RenameTable should have
// been handled at the table level.
}
}
// TODO: handle access to changes in metadata (trigger a reload at least, if
// all else fails).
return a;
}
/**
* Check whether access is simple, or there are granular nuances that need to be
* worked through. Currently if there are no owner-only tables, then everyone's
* access is simple and without nuance.
*/
public hasNuancedAccess(docSession: OptDocSession): boolean {
if (this._clauses.length === 0) { return false; }
return !this.hasFullAccess(docSession);
}
/**
* Check whether user can read everything in document.
*/
public canReadEverything(docSession: OptDocSession): boolean {
for (const tableId of this.getTablesInClauses()) {
const tableData = this.getTableAccess(docSession, tableId);
if (!(tableData.permission & Permissions.VIEW) || tableData.rowPermissionFunctions.length > 0 || tableData.columnPermissions.size > 0) {
return false;
}
}
return true;
}
/**
* Check whether user has owner-level access to the document.
*/
public hasFullAccess(docSession: OptDocSession): boolean {
const access = getDocSessionAccess(docSession);
return access === 'owners';
}
/**
* Check for view access to the document. For most code paths, a request or message
* won't even be considered if there isn't view access, but there's no harm in double
* checking.
*/
public hasViewAccess(docSession: OptDocSession): boolean {
const access = getDocSessionAccess(docSession);
return canView(access);
}
/**
*
* If the user does not have access to the full document, we need to filter out
* parts of the document metadata. For simplicity, we overwrite rather than
* filter for now, so that the overall structure remains consistent. We overwrite:
*
* - names, textual ids, formulas, and other textual options
* - foreign keys linking columns/views/sections back to a forbidden table
*
* On the client, a page with a blank name will be marked gracefully as unavailable.
*
* Some information leaks, for example the existence of private tables and how
* many columns they had, and something of the relationships between them. Long term,
* it could be better to zap rows entirely, and do the work of cleaning up any cross
* references to them.
*
*/
public filterMetaTables(docSession: OptDocSession,
tables: {[key: string]: TableDataAction}): {[key: string]: TableDataAction} {
// If user has right to read everything, return immediately.
if (this.canReadEverything(docSession)) { return tables; }
// If we are going to modify metadata, make a copy.
tables = JSON.parse(JSON.stringify(tables));
// Collect a list of all tables (by tableRef) to which the user has no access.
const censoredTables: Set<number> = new Set();
// Collect a list of censored columns (by "<tableRef> <colId>").
const columnCode = (tableRef: number, colId: string) => `${tableRef} ${colId}`;
const censoredColumnCodes: Set<string> = new Set();
for (const tableId of this.getTablesInClauses()) {
const tableAccess = this.getTableAccess(docSession, tableId);
let tableRef: number|undefined = 0;
if (!(tableAccess.permission & Permissions.VIEW)) {
tableRef = this._docData.getTable('_grist_Tables')?.findRow('tableId', tableId);
if (tableRef) { censoredTables.add(tableRef); }
}
for (const [colId, perm] of tableAccess.columnPermissions) {
if (perm.forbidden & Permissions.VIEW) {
if (!tableRef) {
tableRef = this._docData.getTable('_grist_Tables')?.findRow('tableId', tableId);
}
if (tableRef) { censoredColumnCodes.add(columnCode(tableRef, colId)); }
}
}
}
// Collect a list of all sections and views containing a table to which the user has no access.
const censoredSections: Set<number> = new Set();
const censoredViews: Set<number> = new Set();
for (const section of this._docData.getTable('_grist_Views_section')?.getRecords() || []) {
if (!censoredTables.has(section.tableRef as number)) { continue; }
if (section.parentId) { censoredViews.add(section.parentId as number); }
censoredSections.add(section.id);
}
// Collect a list of all columns from tables to which the user has no access.
const censoredColumns: Set<number> = new Set();
for (const column of this._docData.getTable('_grist_Tables_column')?.getRecords() || []) {
if (censoredTables.has(column.parentId as number) ||
censoredColumnCodes.has(columnCode(column.parentId as number, column.colId as string))) {
censoredColumns.add(column.id);
}
}
// Collect a list of all fields from sections to which the user has no access.
const censoredFields: Set<number> = new Set();
for (const field of this._docData.getTable('_grist_Views_section_field')?.getRecords() || []) {
if (!censoredSections.has(field.parentId as number) &&
!censoredColumns.has(field.colRef as number)) { continue; }
censoredFields.add(field.id);
}
// Clear the tableId for any tables the user does not have access to. This is just
// to keep the name of the table private, in case its name itself is sensitive.
// TODO: tableId may appear elsewhere, such as in _grist_ACLResources - user with
// nuanced rights probably should not receive that table.
this._censor(tables._grist_Tables, censoredTables, (idx, cols) => {
cols.tableId[idx] = '';
});
// Clear the name of private views, in case the name itself is sensitive.
this._censor(tables._grist_Views, censoredViews, (idx, cols) => {
cols.name[idx] = '';
});
// Clear the title of private sections, and break the connection with the private
// table as extra grit in the way of snooping.
this._censor(tables._grist_Views_section, censoredSections, (idx, cols) => {
cols.title[idx] = '';
cols.tableRef[idx] = 0;
});
// Clear text metadata from private columns, and break the connection with the
// private table.
this._censor(tables._grist_Tables_column, censoredColumns, (idx, cols) => {
cols.label[idx] = cols.colId[idx] = '';
cols.widgetOptions[idx] = cols.formula[idx] = '';
cols.type[idx] = 'Any';
cols.parentId[idx] = 0;
});
// Clear text metadata from private fields, and break the connection with the
// private table.
this._censor(tables._grist_Views_section_field, censoredFields, (idx, cols) => {
cols.widgetOptions[idx] = cols.filter[idx] = '';
cols.parentId[idx] = 0;
});
return tables;
}
/**
* Distill the clauses for the given session and table, to figure out the
* access level and any row-level access functions needed.
*/
public getTableAccess(docSession: OptDocSession, tableId: string): TableAccess {
const access = getDocSessionAccess(docSession);
const characteristics: {[key: string]: CellValue} = {};
const user = getDocSessionUser(docSession);
characteristics.Access = access;
characteristics.UserID = user?.id || null;
characteristics.Email = user?.email || null;
characteristics.Name = user?.name || null;
// Light wrapper around characteristics.
const ch: InfoView = {
get(key: string) { return characteristics[key]; },
toJSON() { return characteristics; }
};
const tableAccess: TableAccess = { permission: 0, rowPermissionFunctions: [],
columnPermissions: new Map() };
let canChangeSchema: boolean = true;
let canView: boolean = true;
// Don't apply access control to system requests (important to load characteristic
// tables).
if (docSession.mode !== 'system') {
for (const clause of this._clauses) {
switch (clause.kind) {
case 'doc':
{
const match = getMatchFunc(clause.match);
if (!match({ ch })) {
canChangeSchema = false;
}
}
break;
case 'table':
if (clause.tableId === tableId) {
const match = getMatchFunc(clause.match);
if (!match({ ch })) {
canView = false;
}
}
break;
case 'row':
if (clause.tableId === tableId) {
const scope = clause.scope ? getMatchFunc(clause.scope) : () => true;
if (scope({ ch })) {
const match = getMatchFunc(clause.match);
tableAccess.rowPermissionFunctions.push((rec) => {
return match({ ch, rec }) ? Permissions.OWNER : 0;
});
}
}
break;
case 'column':
if (clause.tableId === tableId) {
const isMatch = getMatchFunc(clause.match)({ ch });
for (const colId of clause.colIds) {
if (PermissionConstraint.needUpdate(isMatch, clause)) {
let perms = tableAccess.columnPermissions.get(colId);
if (!perms) {
perms = new PermissionConstraint();
tableAccess.columnPermissions.set(colId, perms);
}
perms.update(isMatch, clause);
}
}
}
break;
case 'character':
{
const key = this._getCharacteristicTableKey(clause);
const characteristicTable = this._characteristicTables.get(key);
if (characteristicTable) {
const character = this._normalizeValue(characteristics[clause.charId]);
const rowNum = characteristicTable.rowNums.get(character);
if (rowNum !== undefined) {
const rec = new RecordView(characteristicTable.data, rowNum);
for (const key of Object.keys(characteristicTable.data[3])) {
characteristics[key] = rec.get(key);
}
}
}
}
break;
default:
// Don't fail terminally if a clause is not understood, to preserve some
// document access.
// TODO: figure out a way to communicate problems to an appropriate user, so
// they know if a clause is not being honored.
log.error('problem clause: %s', clause);
break;
}
}
}
tableAccess.permission = canView ? Permissions.OWNER : 0;
if (!canChangeSchema) {
tableAccess.permission = tableAccess.permission & ~Permissions.SCHEMA_EDIT;
}
return tableAccess;
}
/**
* Get the set of all tables mentioned in access clauses.
*/
public getTablesInClauses(): Set<string> {
const tables = new Set<string>();
for (const clause of this._clauses) {
if ('tableId' in clause) { tables.add(clause.tableId); }
}
return tables;
}
/**
* Modify table data in place, removing any rows or columns to which access
* is not granted.
*/
public filterData(data: TableDataAction, tableAccess: TableAccess) {
this.filterRows(data, tableAccess);
this.filterColumns(data[3], tableAccess);
}
/**
* Modify table data in place, removing any rows to which access
* is not granted.
*/
public filterRows(data: TableDataAction, tableAccess: TableAccess) {
const toRemove: number[] = [];
const rec = new RecordView(data, 0);
for (let idx = 0; idx < data[2].length; idx++) {
rec.index = idx;
let permission = Permissions.OWNER;
for (const fn of tableAccess.rowPermissionFunctions) {
permission = permission & fn(rec);
}
if (!(permission & Permissions.VIEW)) {
toRemove.push(idx);
}
}
if (toRemove.length > 0) {
pullAt(data[2], toRemove);
const cols = data[3];
for (const [, values] of Object.entries(cols)) {
pullAt(values, toRemove);
}
}
}
/**
* Modify table data in place, removing any columns to which access
* is not granted.
*/
public filterColumns(data: BulkColValues|ColValues, tableAccess: TableAccess) {
const colIds= [...tableAccess.columnPermissions.entries()].map(([colId, p]) => {
return (p.forbidden & Permissions.VIEW) ? colId : null;
}).filter(c => c !== null) as string[];
for (const colId of colIds) {
delete data[colId];
}
}
/**
* Modify the given TableDataAction in place by calling the supplied operation with
* the indexes of any ids supplied and the columns in that TableDataAction.
*/
private _censor(table: TableDataAction, ids: Set<number>,
op: (idx: number, cols: BulkColValues) => unknown) {
const availableIds = table[2];
const cols = table[3];
for (let idx = 0; idx < availableIds.length; idx++) {
if (ids.has(availableIds[idx])) { op(idx, cols); }
}
}
/**
* When comparing user characteristics, we lowercase for the sake of email comparison.
* This is a bit weak.
*/
private _normalizeValue(value: CellValue): string {
return JSON.stringify(value).toLowerCase();
}
/**
* Load any tables needed for look-ups.
*/
private async _updateCharacteristicTables() {
this._characteristicTables.clear();
for (const clause of this._clauses) {
if (clause.kind === 'character') {
this._updateCharacteristicTable(clause);
}
}
}
/**
* Load a table needed for look-up.
*/
private async _updateCharacteristicTable(clause: GranularAccessCharacteristicsClause) {
const key = this._getCharacteristicTableKey(clause);
const data = await this._fetchQuery({tableId: clause.tableId, filters: {}});
const rowNums = new Map<string, number>();
const matches = data[3][clause.lookupColId];
for (let i = 0; i < matches.length; i++) {
rowNums.set(this._normalizeValue(matches[i]), i);
}
const result: CharacteristicTable = {
tableId: clause.tableId,
colId: clause.lookupColId,
rowNums,
data
}
this._characteristicTables.set(key, result);
}
private _getCharacteristicTableKey(clause: GranularAccessCharacteristicsClause): string {
return JSON.stringify({ tableId: clause.tableId, colId: clause.lookupColId });
}
}
// A function that computes permissions given a record.
export type PermissionFunction = (rec: RecordView) => number;
// A summary of table-level access information.
export interface TableAccess {
permission: number;
rowPermissionFunctions: Array<PermissionFunction>;
columnPermissions: Map<string, PermissionConstraint>;
}
/**
* This is a placeholder for accumulating permissions for a particular scope.
*/
export class PermissionConstraint {
private _allowed: number = 0;
private _forbidden: number = 0;
// If a clause's condition matches the user, or fails to match the user,
// check if the clause could modify permissions via onMatch/onFail.
public static needUpdate(isMatch: boolean, clause: GranularAccessColumnClause) {
return (isMatch && clause.onMatch) || (!isMatch && clause.onFail);
}
public constructor() {
this._allowed = this._forbidden = 0;
}
public get allowed() {
return this._allowed;
}
public get forbidden() {
return this._forbidden;
}
public allow(p: number) {
this._allowed = this._allowed | p;
this._forbidden = this._forbidden & ~p;
}
public allowOnly(p: number) {
this._allowed = p;
this._forbidden = ~p;
}
public forbid(p: number) {
this._forbidden = this._forbidden | p;
this._allowed = this._allowed & ~p;
}
// Update this PermissionConstraint based on whether the user matched/did not match
// a particular clause.
public update(isMatch: boolean, clause: GranularAccessColumnClause) {
const activeClause = (isMatch ? clause.onMatch : clause.onFail) || {};
if (activeClause.allow) {
this.allow(getPermission(activeClause.allow));
}
if (activeClause.allowOnly) {
this.allowOnly(getPermission(activeClause.allowOnly));
}
if (activeClause.forbid) {
this.forbid(getPermission(activeClause.forbid));
}
}
}
// Light wrapper around characteristics or records.
export interface InfoView {
get(key: string): CellValue;
toJSON(): {[key: string]: any};
}
// A row-like view of TableDataAction, which is columnar in nature.
export class RecordView implements InfoView {
public constructor(public data: TableDataAction, public index: number) {
}
public get(colId: string): CellValue {
if (colId === 'id') {
return this.data[2][this.index];
}
return this.data[3][colId][this.index];
}
public toJSON() {
const results: {[key: string]: any} = {};
for (const key of Object.keys(this.data[3])) {
results[key] = this.data[3][key][this.index];
}
return results;
}
}
// A function for matching characteristic and/or record information.
export type MatchFunc = (state: { ch?: InfoView, rec?: InfoView }) => boolean;
// Convert a match specification to a function.
export function getMatchFunc(spec: MatchSpec): MatchFunc {
switch (spec.kind) {
case 'not':
{
const core = getMatchFunc(spec.match);
return (state) => !core(state);
}
case 'const':
return (state) => state.ch?.get(spec.charId) === spec.value;
case 'truthy':
return (state) => Boolean(state.rec?.get(spec.colId));
case 'pair':
return (state) => state.ch?.get(spec.charId) === state.rec?.get(spec.colId);
default:
throw new Error('match spec not understood');
}
}
/**
* A cache of a table needed for look-ups, including a map from keys to
* row numbers. Keys are produced by _getCharacteristicTableKey().
*/
export interface CharacteristicTable {
tableId: string;
colId: string;
rowNums: Map<string, number>;
data: TableDataAction;
}
export function getPermission(accessPermissions: AccessPermissions) {
if (accessPermissions === 'all') { return 255; }
let n: number = 0;
for (const p of accessPermissions) {
switch (p) {
case 'read':
n = n | Permissions.VIEW;
break;
case 'update':
n = n | Permissions.UPDATE;
break;
case 'create':
n = n | Permissions.ADD;
break;
case 'delete':
n = n | Permissions.REMOVE;
break;
default:
throw new Error(`unrecognized permission ${p}`);
}
}
return n;
}