third_party/WebKit/Source/modules/webdatabase/DatabaseAuthorizer.cpp

/*
 * Copyright (C) 2007 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1.  Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 * 2.  Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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 */

#include "modules/webdatabase/DatabaseAuthorizer.h"

#include "wtf/HashSet.h"
#include "wtf/StdLibExtras.h"
#include "wtf/Threading.h"
#include "wtf/text/StringHash.h"

namespace blink {

DatabaseAuthorizer* DatabaseAuthorizer::create(
    const String& databaseInfoTableName) {
  return new DatabaseAuthorizer(databaseInfoTableName);
}

DatabaseAuthorizer::DatabaseAuthorizer(const String& databaseInfoTableName)
    : m_securityEnabled(false), m_databaseInfoTableName(databaseInfoTableName) {
  DCHECK(isMainThread());

  reset();
}

void DatabaseAuthorizer::reset() {
  m_lastActionWasInsert = false;
  m_lastActionChangedDatabase = false;
  m_permissions = ReadWriteMask;
}

void DatabaseAuthorizer::resetDeletes() {
  m_hadDeletes = false;
}

namespace {
using FunctionNameList = HashSet<String, CaseFoldingHash>;

const FunctionNameList& whitelistedFunctions() {
  DEFINE_THREAD_SAFE_STATIC_LOCAL(
      FunctionNameList, list,
      new FunctionNameList({
          // SQLite functions used to help implement some operations
          // ALTER TABLE helpers
          "sqlite_rename_table", "sqlite_rename_trigger",
          // GLOB helpers
          "glob",
          // SQLite core functions
          "abs", "changes", "coalesce", "glob", "ifnull", "hex",
          "last_insert_rowid", "length", "like", "lower", "ltrim", "max", "min",
          "nullif", "quote", "replace", "round", "rtrim", "soundex",
          "sqlite_source_id", "sqlite_version", "substr", "total_changes",
          "trim", "typeof", "upper", "zeroblob",
          // SQLite date and time functions
          "date", "time", "datetime", "julianday", "strftime",
          // SQLite aggregate functions
          // max() and min() are already in the list
          "avg", "count", "group_concat", "sum", "total",
          // SQLite FTS functions
          "match", "snippet", "offsets", "optimize",
          // SQLite ICU functions
          // like(), lower() and upper() are already in the list
          "regexp",
      }));
  return list;
}
}

int DatabaseAuthorizer::createTable(const String& tableName) {
  if (!allowWrite())
    return SQLAuthDeny;

  m_lastActionChangedDatabase = true;
  return denyBasedOnTableName(tableName);
}

int DatabaseAuthorizer::createTempTable(const String& tableName) {
  // SQLITE_CREATE_TEMP_TABLE results in a UPDATE operation, which is not
  // allowed in read-only transactions or private browsing, so we might as
  // well disallow SQLITE_CREATE_TEMP_TABLE in these cases
  if (!allowWrite())
    return SQLAuthDeny;

  return denyBasedOnTableName(tableName);
}

int DatabaseAuthorizer::dropTable(const String& tableName) {
  if (!allowWrite())
    return SQLAuthDeny;

  return updateDeletesBasedOnTableName(tableName);
}

int DatabaseAuthorizer::dropTempTable(const String& tableName) {
  // SQLITE_DROP_TEMP_TABLE results in a DELETE operation, which is not
  // allowed in read-only transactions or private browsing, so we might as
  // well disallow SQLITE_DROP_TEMP_TABLE in these cases
  if (!allowWrite())
    return SQLAuthDeny;

  return updateDeletesBasedOnTableName(tableName);
}

int DatabaseAuthorizer::allowAlterTable(const String&,
                                        const String& tableName) {
  if (!allowWrite())
    return SQLAuthDeny;

  m_lastActionChangedDatabase = true;
  return denyBasedOnTableName(tableName);
}

int DatabaseAuthorizer::createIndex(const String&, const String& tableName) {
  if (!allowWrite())
    return SQLAuthDeny;

  m_lastActionChangedDatabase = true;
  return denyBasedOnTableName(tableName);
}

int DatabaseAuthorizer::createTempIndex(const String&,
                                        const String& tableName) {
  // SQLITE_CREATE_TEMP_INDEX should result in a UPDATE or INSERT operation,
  // which is not allowed in read-only transactions or private browsing,
  // so we might as well disallow SQLITE_CREATE_TEMP_INDEX in these cases
  if (!allowWrite())
    return SQLAuthDeny;

  return denyBasedOnTableName(tableName);
}

int DatabaseAuthorizer::dropIndex(const String&, const String& tableName) {
  if (!allowWrite())
    return SQLAuthDeny;

  return updateDeletesBasedOnTableName(tableName);
}

int DatabaseAuthorizer::dropTempIndex(const String&, const String& tableName) {
  // SQLITE_DROP_TEMP_INDEX should result in a DELETE operation, which is
  // not allowed in read-only transactions or private browsing, so we might
  // as well disallow SQLITE_DROP_TEMP_INDEX in these cases
  if (!allowWrite())
    return SQLAuthDeny;

  return updateDeletesBasedOnTableName(tableName);
}

int DatabaseAuthorizer::createTrigger(const String&, const String& tableName) {
  if (!allowWrite())
    return SQLAuthDeny;

  m_lastActionChangedDatabase = true;
  return denyBasedOnTableName(tableName);
}

int DatabaseAuthorizer::createTempTrigger(const String&,
                                          const String& tableName) {
  // SQLITE_CREATE_TEMP_TRIGGER results in a INSERT operation, which is not
  // allowed in read-only transactions or private browsing, so we might as
  // well disallow SQLITE_CREATE_TEMP_TRIGGER in these cases
  if (!allowWrite())
    return SQLAuthDeny;

  return denyBasedOnTableName(tableName);
}

int DatabaseAuthorizer::dropTrigger(const String&, const String& tableName) {
  if (!allowWrite())
    return SQLAuthDeny;

  return updateDeletesBasedOnTableName(tableName);
}

int DatabaseAuthorizer::dropTempTrigger(const String&,
                                        const String& tableName) {
  // SQLITE_DROP_TEMP_TRIGGER results in a DELETE operation, which is not
  // allowed in read-only transactions or private browsing, so we might as
  // well disallow SQLITE_DROP_TEMP_TRIGGER in these cases
  if (!allowWrite())
    return SQLAuthDeny;

  return updateDeletesBasedOnTableName(tableName);
}

int DatabaseAuthorizer::createView(const String&) {
  return (!allowWrite() ? SQLAuthDeny : SQLAuthAllow);
}

int DatabaseAuthorizer::createTempView(const String&) {
  // SQLITE_CREATE_TEMP_VIEW results in a UPDATE operation, which is not
  // allowed in read-only transactions or private browsing, so we might as
  // well disallow SQLITE_CREATE_TEMP_VIEW in these cases
  return (!allowWrite() ? SQLAuthDeny : SQLAuthAllow);
}

int DatabaseAuthorizer::dropView(const String&) {
  if (!allowWrite())
    return SQLAuthDeny;

  m_hadDeletes = true;
  return SQLAuthAllow;
}

int DatabaseAuthorizer::dropTempView(const String&) {
  // SQLITE_DROP_TEMP_VIEW results in a DELETE operation, which is not
  // allowed in read-only transactions or private browsing, so we might as
  // well disallow SQLITE_DROP_TEMP_VIEW in these cases
  if (!allowWrite())
    return SQLAuthDeny;

  m_hadDeletes = true;
  return SQLAuthAllow;
}

int DatabaseAuthorizer::createVTable(const String& tableName,
                                     const String& moduleName) {
  if (!allowWrite())
    return SQLAuthDeny;

  // Allow only the FTS3 extension
  if (!equalIgnoringCase(moduleName, "fts3"))
    return SQLAuthDeny;

  m_lastActionChangedDatabase = true;
  return denyBasedOnTableName(tableName);
}

int DatabaseAuthorizer::dropVTable(const String& tableName,
                                   const String& moduleName) {
  if (!allowWrite())
    return SQLAuthDeny;

  // Allow only the FTS3 extension
  if (!equalIgnoringCase(moduleName, "fts3"))
    return SQLAuthDeny;

  return updateDeletesBasedOnTableName(tableName);
}

int DatabaseAuthorizer::allowDelete(const String& tableName) {
  if (!allowWrite())
    return SQLAuthDeny;

  return updateDeletesBasedOnTableName(tableName);
}

int DatabaseAuthorizer::allowInsert(const String& tableName) {
  if (!allowWrite())
    return SQLAuthDeny;

  m_lastActionChangedDatabase = true;
  m_lastActionWasInsert = true;
  return denyBasedOnTableName(tableName);
}

int DatabaseAuthorizer::allowUpdate(const String& tableName, const String&) {
  if (!allowWrite())
    return SQLAuthDeny;

  m_lastActionChangedDatabase = true;
  return denyBasedOnTableName(tableName);
}

int DatabaseAuthorizer::allowTransaction() {
  return m_securityEnabled ? SQLAuthDeny : SQLAuthAllow;
}

int DatabaseAuthorizer::allowRead(const String& tableName, const String&) {
  if (m_permissions & NoAccessMask && m_securityEnabled)
    return SQLAuthDeny;

  return denyBasedOnTableName(tableName);
}

int DatabaseAuthorizer::allowReindex(const String&) {
  return (!allowWrite() ? SQLAuthDeny : SQLAuthAllow);
}

int DatabaseAuthorizer::allowAnalyze(const String& tableName) {
  return denyBasedOnTableName(tableName);
}

int DatabaseAuthorizer::allowPragma(const String&, const String&) {
  return m_securityEnabled ? SQLAuthDeny : SQLAuthAllow;
}

int DatabaseAuthorizer::allowAttach(const String&) {
  return m_securityEnabled ? SQLAuthDeny : SQLAuthAllow;
}

int DatabaseAuthorizer::allowDetach(const String&) {
  return m_securityEnabled ? SQLAuthDeny : SQLAuthAllow;
}

int DatabaseAuthorizer::allowFunction(const String& functionName) {
  if (m_securityEnabled && !whitelistedFunctions().contains(functionName))
    return SQLAuthDeny;

  return SQLAuthAllow;
}

void DatabaseAuthorizer::disable() {
  m_securityEnabled = false;
}

void DatabaseAuthorizer::enable() {
  m_securityEnabled = true;
}

bool DatabaseAuthorizer::allowWrite() {
  return !(m_securityEnabled &&
           (m_permissions & ReadOnlyMask || m_permissions & NoAccessMask));
}

void DatabaseAuthorizer::setPermissions(int permissions) {
  m_permissions = permissions;
}

int DatabaseAuthorizer::denyBasedOnTableName(const String& tableName) const {
  if (!m_securityEnabled)
    return SQLAuthAllow;

  // Sadly, normal creates and drops end up affecting sqlite_master in an
  // authorizer callback, so it will be tough to enforce all of the following
  // policies:
  // if (equalIgnoringCase(tableName, "sqlite_master") ||
  //     equalIgnoringCase(tableName, "sqlite_temp_master") ||
  //     equalIgnoringCase(tableName, "sqlite_sequence") ||
  //     equalIgnoringCase(tableName, Database::databaseInfoTableName()))
  //   return SQLAuthDeny;

  if (equalIgnoringCase(tableName, m_databaseInfoTableName))
    return SQLAuthDeny;

  return SQLAuthAllow;
}

int DatabaseAuthorizer::updateDeletesBasedOnTableName(const String& tableName) {
  int allow = denyBasedOnTableName(tableName);
  if (allow)
    m_hadDeletes = true;
  return allow;
}

}  // namespace blink