path: root/onlineupdate/source/service/serviceinstall.cxx

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include <windows.h>
#include <aclapi.h>
#include <stdlib.h>
#include <shlwapi.h>

// Used for DNLEN and UNLEN
#include <lm.h>

#include "serviceinstall.hxx"
#include "servicebase.hxx"
#include "updatehelper.h"
#include "shellapi.h"
#include "readstrings.h"
#include "errors.h"

#include <memory>

#pragma comment(lib, "version.lib")

namespace {

struct AutoServiceHandle
{
    AutoServiceHandle(SC_HANDLE handle):
        mHandle(handle)
    {
    }

    ~AutoServiceHandle()
    {
        releaseHandle(mHandle);
    }

    void releaseHandle(SC_HANDLE handle)
    {
        if (handle != nullptr)
            CloseServiceHandle(handle);
    }

    SC_HANDLE get() const
    {
        return mHandle;
    }

    operator bool() const
    {
        return mHandle != nullptr;
    }

    void reset(SC_HANDLE handle = nullptr)
    {
        releaseHandle(mHandle);
        mHandle = handle;
    }

    SC_HANDLE mHandle;
};

}

/**
 * A wrapper function to read strings for the maintenance service.
 *
 * @param path    The path of the ini file to read from
 * @param results The maintenance service strings that were read
 * @return OK on success
*/
static int
ReadMaintenanceServiceStrings(LPCWSTR path,
                              MaintenanceServiceStringTable *results)
{
    // Read in the maintenance service description string if specified.
    const unsigned int kNumStrings = 1;
    // TODO: moggi: needs adaptation for LibreOffice
    const char *kServiceKeys = "MozillaMaintenanceDescription\0";
    char serviceStrings[kNumStrings][MAX_TEXT_LEN];
    int result = ReadStrings(path, kServiceKeys,
                             kNumStrings, serviceStrings);
    if (result != OK)
    {
        serviceStrings[0][0] = '\0';
    }
    strncpy(results->serviceDescription,
            serviceStrings[0], MAX_TEXT_LEN - 1);
    results->serviceDescription[MAX_TEXT_LEN - 1] = '\0';
    return result;
}

/**
 * Obtains the version number from the specified PE file's version information
 * Version Format: A.B.C.D (Example 10.0.0.300)
 *
 * @param  path The path of the file to check the version on
 * @param  A    The first part of the version number
 * @param  B    The second part of the version number
 * @param  C    The third part of the version number
 * @param  D    The fourth part of the version number
 * @return TRUE if successful
 */
static BOOL
GetVersionNumberFromPath(LPWSTR path, DWORD &A, DWORD &B,
                         DWORD &C, DWORD &D)
{
    DWORD fileVersionInfoSize = GetFileVersionInfoSizeW(path, 0);
    std::unique_ptr<char[]> fileVersionInfo(new char[fileVersionInfoSize]);
    if (!GetFileVersionInfoW(path, 0, fileVersionInfoSize,
                             fileVersionInfo.get()))
    {
        LOG_WARN(("Could not obtain file info of old service.  (%d)",
                  GetLastError()));
        return FALSE;
    }

    VS_FIXEDFILEINFO *fixedFileInfo =
        reinterpret_cast<VS_FIXEDFILEINFO *>(fileVersionInfo.get());
    UINT size;
    if (!VerQueryValueW(fileVersionInfo.get(), L"\\",
                        reinterpret_cast<LPVOID*>(&fixedFileInfo), &size))
    {
        LOG_WARN(("Could not query file version info of old service.  (%d)",
                  GetLastError()));
        return FALSE;
    }

    A = HIWORD(fixedFileInfo->dwFileVersionMS);
    B = LOWORD(fixedFileInfo->dwFileVersionMS);
    C = HIWORD(fixedFileInfo->dwFileVersionLS);
    D = LOWORD(fixedFileInfo->dwFileVersionLS);
    return TRUE;
}

/**
 * Updates the service description with what is stored in updater.ini
 * at the same path as the currently executing module binary.
 *
 * @param serviceHandle A handle to an opened service with
 *                      SERVICE_CHANGE_CONFIG access right
 * @param TRUE on success.
*/
BOOL
UpdateServiceDescription(SC_HANDLE serviceHandle)
{
    WCHAR updaterINIPath[MAX_PATH + 1];
    if (!GetModuleFileNameW(nullptr, updaterINIPath,
                            sizeof(updaterINIPath) /
                            sizeof(updaterINIPath[0])))
    {
        LOG_WARN(("Could not obtain module filename when attempting to "
                  "modify service description.  (%d)", GetLastError()));
        return FALSE;
    }

    if (!PathRemoveFileSpecW(updaterINIPath))
    {
        LOG_WARN(("Could not remove file spec when attempting to "
                  "modify service description.  (%d)", GetLastError()));
        return FALSE;
    }

    if (!PathAppendSafe(updaterINIPath, L"updater.ini"))
    {
        LOG_WARN(("Could not append updater.ini filename when attempting to "
                  "modify service description.  (%d)", GetLastError()));
        return FALSE;
    }

    if (GetFileAttributesW(updaterINIPath) == INVALID_FILE_ATTRIBUTES)
    {
        LOG_WARN(("updater.ini file does not exist, will not modify "
                  "service description.  (%d)", GetLastError()));
        return FALSE;
    }

    MaintenanceServiceStringTable serviceStrings;
    int rv = ReadMaintenanceServiceStrings(updaterINIPath, &serviceStrings);
    if (rv != OK || !strlen(serviceStrings.serviceDescription))
    {
        LOG_WARN(("updater.ini file does not contain a maintenance "
                  "service description."));
        return FALSE;
    }

    WCHAR serviceDescription[MAX_TEXT_LEN];
    if (!MultiByteToWideChar(CP_UTF8, 0,
                             serviceStrings.serviceDescription, -1,
                             serviceDescription,
                             sizeof(serviceDescription) /
                             sizeof(serviceDescription[0])))
    {
        LOG_WARN(("Could not convert description to wide string format.  (%d)",
                  GetLastError()));
        return FALSE;
    }

    SERVICE_DESCRIPTIONW descriptionConfig;
    descriptionConfig.lpDescription = serviceDescription;
    if (!ChangeServiceConfig2W(serviceHandle,
                               SERVICE_CONFIG_DESCRIPTION,
                               &descriptionConfig))
    {
        LOG_WARN(("Could not change service config.  (%d)", GetLastError()));
        return FALSE;
    }

    LOG(("The service description was updated successfully."));
    return TRUE;
}

/**
 * Determines if the MozillaMaintenance service path needs to be updated
 * and fixes it if it is wrong.
 *
 * @param service             A handle to the service to fix.
 * @param currentServicePath  The current (possibly wrong) path that is used.
 * @param servicePathWasWrong Out parameter set to TRUE if a fix was needed.
 * @return TRUE if the service path is now correct.
*/
BOOL
FixServicePath(SC_HANDLE service,
               LPCWSTR currentServicePath,
               BOOL &servicePathWasWrong)
{
    // When we originally upgraded the MozillaMaintenance service we
    // would uninstall the service on each upgrade.  This had an
    // intermittent error which could cause the service to use the file
    // maintenanceservice_tmp.exe as the install path.  Only a small number
    // of Nightly users would be affected by this, but we check for this
    // state here and fix the user if they are affected.
    //
    // We also fix the path in the case of the path not being quoted.
    size_t currentServicePathLen = wcslen(currentServicePath);
    bool doesServiceHaveCorrectPath =
        currentServicePathLen > 2 &&
        !wcsstr(currentServicePath, L"maintenanceservice_tmp.exe") &&
        currentServicePath[0] == L'\"' &&
        currentServicePath[currentServicePathLen - 1] == L'\"';

    if (doesServiceHaveCorrectPath)
    {
        LOG(("The MozillaMaintenance service path is correct."));
        servicePathWasWrong = FALSE;
        return TRUE;
    }
    // This is a recoverable situation so not logging as a warning
    LOG(("The MozillaMaintenance path is NOT correct. It was: %ls",
         currentServicePath));

    servicePathWasWrong = TRUE;
    WCHAR fixedPath[MAX_PATH + 1] = { L'\0' };
    wcsncpy(fixedPath, currentServicePath, MAX_PATH);
    PathUnquoteSpacesW(fixedPath);
    if (!PathRemoveFileSpecW(fixedPath))
    {
        LOG_WARN(("Couldn't remove file spec.  (%d)", GetLastError()));
        return FALSE;
    }
    if (!PathAppendSafe(fixedPath, L"maintenanceservice.exe"))
    {
        LOG_WARN(("Couldn't append file spec.  (%d)", GetLastError()));
        return FALSE;
    }
    PathQuoteSpacesW(fixedPath);


    if (!ChangeServiceConfigW(service, SERVICE_NO_CHANGE, SERVICE_NO_CHANGE,
                              SERVICE_NO_CHANGE, fixedPath, nullptr, nullptr,
                              nullptr, nullptr, nullptr, nullptr))
    {
        LOG_WARN(("Could not fix service path.  (%d)", GetLastError()));
        return FALSE;
    }

    LOG(("Fixed service path to: %ls.", fixedPath));
    return TRUE;
}

/**
 * Installs or upgrades the SVC_NAME service.
 * If an existing service is already installed, we replace it with the
 * currently running process.
 *
 * @param  action The action to perform.
 * @return TRUE if the service was installed/upgraded
 */
BOOL
SvcInstall(SvcInstallAction action)
{
    // Get a handle to the local computer SCM database with full access rights.
    AutoServiceHandle schSCManager(OpenSCManager(nullptr, nullptr,
                                   SC_MANAGER_ALL_ACCESS));
    if (!schSCManager)
    {
        LOG_WARN(("Could not open service manager.  (%d)", GetLastError()));
        return FALSE;
    }

    WCHAR newServiceBinaryPath[MAX_PATH + 1];
    if (!GetModuleFileNameW(nullptr, newServiceBinaryPath,
                            sizeof(newServiceBinaryPath) /
                            sizeof(newServiceBinaryPath[0])))
    {
        LOG_WARN(("Could not obtain module filename when attempting to "
                  "install service.  (%d)",
                  GetLastError()));
        return FALSE;
    }

    // Check if we already have the service installed.
    AutoServiceHandle schService(OpenServiceW(schSCManager.get(),
                                 SVC_NAME,
                                 SERVICE_ALL_ACCESS));
    DWORD lastError = GetLastError();
    if (!schService && ERROR_SERVICE_DOES_NOT_EXIST != lastError)
    {
        // The service exists but we couldn't open it
        LOG_WARN(("Could not open service.  (%d)", GetLastError()));
        return FALSE;
    }

    if (schService)
    {
        // The service exists but it may not have the correct permissions.
        // This could happen if the permissions were not set correctly originally
        // or have been changed after the installation.  This will reset the
        // permissions back to allow limited user accounts.
        if (!SetUserAccessServiceDACL(schService.get()))
        {
            LOG_WARN(("Could not reset security ACE on service handle. It might not be "
                      "possible to start the service. This error should never "
                      "happen.  (%d)", GetLastError()));
        }

        // The service exists and we opened it
        DWORD bytesNeeded;
        if (!QueryServiceConfigW(schService.get(), nullptr, 0, &bytesNeeded) &&
                GetLastError() != ERROR_INSUFFICIENT_BUFFER)
        {
            LOG_WARN(("Could not determine buffer size for query service config.  (%d)",
                      GetLastError()));
            return FALSE;
        }

        // Get the service config information, in particular we want the binary
        // path of the service.
        std::unique_ptr<char[]> serviceConfigBuffer(new char[bytesNeeded]);
        if (!QueryServiceConfigW(schService.get(),
                                 reinterpret_cast<QUERY_SERVICE_CONFIGW*>(serviceConfigBuffer.get()),
                                 bytesNeeded, &bytesNeeded))
        {
            LOG_WARN(("Could open service but could not query service config.  (%d)",
                      GetLastError()));
            return FALSE;
        }
        QUERY_SERVICE_CONFIGW &serviceConfig =
            *reinterpret_cast<QUERY_SERVICE_CONFIGW*>(serviceConfigBuffer.get());

        // Check if we need to fix the service path
        BOOL servicePathWasWrong;
        static BOOL alreadyCheckedFixServicePath = FALSE;
        if (!alreadyCheckedFixServicePath)
        {
            if (!FixServicePath(schService.get(), serviceConfig.lpBinaryPathName,
                                servicePathWasWrong))
            {
                LOG_WARN(("Could not fix service path. This should never happen.  (%d)",
                          GetLastError()));
                // True is returned because the service is pointing to
                // maintenanceservice_tmp.exe so it actually was upgraded to the
                // newest installed service.
                return TRUE;
            }
            else if (servicePathWasWrong)
            {
                // Now that the path is fixed we should re-attempt the install.
                // This current process' image path is maintenanceservice_tmp.exe.
                // The service used to point to maintenanceservice_tmp.exe.
                // The service was just fixed to point to maintenanceservice.exe.
                // Re-attempting an install from scratch will work as normal.
                alreadyCheckedFixServicePath = TRUE;
                LOG(("Restarting install action: %d", action));
                return SvcInstall(action);
            }
        }

        // Ensure the service path is not quoted. We own this memory and know it to
        // be large enough for the quoted path, so it is large enough for the
        // unquoted path.  This function cannot fail.
        PathUnquoteSpacesW(serviceConfig.lpBinaryPathName);

        // Obtain the existing maintenanceservice file's version number and
        // the new file's version number.  Versions are in the format of
        // A.B.C.D.
        DWORD existingA, existingB, existingC, existingD;
        DWORD newA, newB, newC, newD;
        BOOL obtainedExistingVersionInfo =
            GetVersionNumberFromPath(serviceConfig.lpBinaryPathName,
                                     existingA, existingB,
                                     existingC, existingD);
        if (!GetVersionNumberFromPath(newServiceBinaryPath, newA,
                                      newB, newC, newD))
        {
            LOG_WARN(("Could not obtain version number from new path"));
            return FALSE;
        }

        // Check if we need to replace the old binary with the new one
        // If we couldn't get the old version info then we assume we should
        // replace it.
        if (ForceInstallSvc == action ||
                !obtainedExistingVersionInfo ||
                (existingA < newA) ||
                (existingA == newA && existingB < newB) ||
                (existingA == newA && existingB == newB &&
                 existingC < newC) ||
                (existingA == newA && existingB == newB &&
                 existingC == newC && existingD < newD))
        {

            // We have a newer updater, so update the description from the INI file.
            UpdateServiceDescription(schService.get());

            schService.reset();
            if (!StopService())
            {
                return FALSE;
            }

            if (!wcscmp(newServiceBinaryPath, serviceConfig.lpBinaryPathName))
            {
                LOG(("File is already in the correct location, no action needed for "
                     "upgrade.  The path is: \"%ls\"", newServiceBinaryPath));
                return TRUE;
            }

            BOOL result = TRUE;

            // Attempt to copy the new binary over top the existing binary.
            // If there is an error we try to move it out of the way and then
            // copy it in.  First try the safest / easiest way to overwrite the file.
            if (!CopyFileW(newServiceBinaryPath,
                           serviceConfig.lpBinaryPathName, FALSE))
            {
                LOG_WARN(("Could not overwrite old service binary file. "
                          "This should never happen, but if it does the next "
                          "upgrade will fix it, the service is not a critical "
                          "component that needs to be installed for upgrades "
                          "to work.  (%d)", GetLastError()));

                // We rename the last 3 filename chars in an unsafe way.  Manually
                // verify there are more than 3 chars for safe failure in MoveFileExW.
                const size_t len = wcslen(serviceConfig.lpBinaryPathName);
                if (len > 3)
                {
                    // Calculate the temp file path that we're moving the file to. This
                    // is the same as the proper service path but with a .old extension.
                    LPWSTR oldServiceBinaryTempPath =
                        new WCHAR[len + 1];
                    memset(oldServiceBinaryTempPath, 0, (len + 1) * sizeof (WCHAR));
                    wcsncpy(oldServiceBinaryTempPath, serviceConfig.lpBinaryPathName, len);
                    // Rename the last 3 chars to 'old'
                    wcsncpy(oldServiceBinaryTempPath + len - 3, L"old", 3);

                    // Move the current (old) service file to the temp path.
                    if (MoveFileExW(serviceConfig.lpBinaryPathName,
                                    oldServiceBinaryTempPath,
                                    MOVEFILE_REPLACE_EXISTING | MOVEFILE_WRITE_THROUGH))
                    {
                        // The old binary is moved out of the way, copy in the new one.
                        if (!CopyFileW(newServiceBinaryPath,
                                       serviceConfig.lpBinaryPathName, FALSE))
                        {
                            // It is best to leave the old service binary in this condition.
                            LOG_WARN(("The new service binary could not be copied in."
                                      " The service will not be upgraded."));
                            result = FALSE;
                        }
                        else
                        {
                            LOG(("The new service binary was copied in by first moving the"
                                 " old one out of the way."));
                        }

                        // Attempt to get rid of the old service temp path.
                        if (DeleteFileW(oldServiceBinaryTempPath))
                        {
                            LOG(("The old temp service path was deleted: %ls.",
                                 oldServiceBinaryTempPath));
                        }
                        else
                        {
                            // The old temp path could not be removed.  It will be removed
                            // the next time the user can't copy the binary in or on uninstall.
                            LOG_WARN(("The old temp service path was not deleted."));
                        }
                    }
                    else
                    {
                        // It is best to leave the old service binary in this condition.
                        LOG_WARN(("Could not move old service file out of the way from:"
                                  " \"%ls\" to \"%ls\". Service will not be upgraded.  (%d)",
                                  serviceConfig.lpBinaryPathName,
                                  oldServiceBinaryTempPath, GetLastError()));
                        result = FALSE;
                    }
                    delete[] oldServiceBinaryTempPath;
                }
                else
                {
                    // It is best to leave the old service binary in this condition.
                    LOG_WARN(("Service binary path was less than 3, service will"
                              " not be updated.  This should never happen."));
                    result = FALSE;
                }
            }
            else
            {
                LOG(("The new service binary was copied in."));
            }

            // We made a copy of ourselves to the existing location.
            // The tmp file (the process of which we are executing right now) will be
            // left over.  Attempt to delete the file on the next reboot.
            if (MoveFileExW(newServiceBinaryPath, nullptr,
                            MOVEFILE_DELAY_UNTIL_REBOOT))
            {
                LOG(("Deleting the old file path on the next reboot: %ls.",
                     newServiceBinaryPath));
            }
            else
            {
                LOG_WARN(("Call to delete the old file path failed: %ls.",
                          newServiceBinaryPath));
            }

            return result;
        }

        // We don't need to copy ourselves to the existing location.
        // The tmp file (the process of which we are executing right now) will be
        // left over.  Attempt to delete the file on the next reboot.
        MoveFileExW(newServiceBinaryPath, nullptr, MOVEFILE_DELAY_UNTIL_REBOOT);

        // nothing to do, we already have a newer service installed
        return TRUE;
    }

    // If the service does not exist and we are upgrading, don't install it.
    if (UpgradeSvc == action)
    {
        // The service does not exist and we are upgrading, so don't install it
        return TRUE;
    }

    // Quote the path only if it contains spaces.
    PathQuoteSpacesW(newServiceBinaryPath);
    // The service does not already exist so create the service as on demand
    schService.reset(CreateServiceW(schSCManager.get(), SVC_NAME, SVC_DISPLAY_NAME,
                                    SERVICE_ALL_ACCESS, SERVICE_WIN32_OWN_PROCESS,
                                    SERVICE_DEMAND_START, SERVICE_ERROR_NORMAL,
                                    newServiceBinaryPath, nullptr, nullptr,
                                    nullptr, nullptr, nullptr));
    if (!schService)
    {
        LOG_WARN(("Could not create Windows service. "
                  "This error should never happen since a service install "
                  "should only be called when elevated.  (%d)", GetLastError()));
        return FALSE;
    }

    if (!SetUserAccessServiceDACL(schService.get()))
    {
        LOG_WARN(("Could not set security ACE on service handle, the service will not "
                  "be able to be started from unelevated processes. "
                  "This error should never happen.  (%d)",
                  GetLastError()));
    }

    UpdateServiceDescription(schService.get());

    return TRUE;
}

/**
 * Stops the Maintenance service.
 *
 * @return TRUE if successful.
 */
BOOL
StopService()
{
    // Get a handle to the local computer SCM database with full access rights.
    AutoServiceHandle schSCManager(OpenSCManager(nullptr, nullptr,
                                   SC_MANAGER_ALL_ACCESS));
    if (!schSCManager)
    {
        LOG_WARN(("Could not open service manager.  (%d)", GetLastError()));
        return FALSE;
    }

    // Open the service
    AutoServiceHandle schService(OpenServiceW(schSCManager.get(), SVC_NAME,
                                 SERVICE_ALL_ACCESS));
    if (!schService)
    {
        LOG_WARN(("Could not open service.  (%d)", GetLastError()));
        return FALSE;
    }

    LOG(("Sending stop request..."));
    SERVICE_STATUS status;
    SetLastError(ERROR_SUCCESS);
    if (!ControlService(schService.get(), SERVICE_CONTROL_STOP, &status) &&
            GetLastError() != ERROR_SERVICE_NOT_ACTIVE)
    {
        LOG_WARN(("Error sending stop request.  (%d)", GetLastError()));
    }

    schSCManager.reset();
    schService.reset();

    LOG(("Waiting for service stop..."));
    DWORD lastState = WaitForServiceStop(SVC_NAME, 30);

    // The service can be in a stopped state but the exe still in use
    // so make sure the process is really gone before proceeding
    WaitForProcessExit(L"maintenanceservice.exe", 30);
    LOG(("Done waiting for service stop, last service state: %d", lastState));

    return lastState == SERVICE_STOPPED;
}

/**
 * Uninstalls the Maintenance service.
 *
 * @return TRUE if successful.
 */
BOOL
SvcUninstall()
{
    // Get a handle to the local computer SCM database with full access rights.
    AutoServiceHandle schSCManager(OpenSCManager(nullptr, nullptr,
                                   SC_MANAGER_ALL_ACCESS));
    if (!schSCManager)
    {
        LOG_WARN(("Could not open service manager.  (%d)", GetLastError()));
        return FALSE;
    }

    // Open the service
    AutoServiceHandle schService(OpenServiceW(schSCManager.get(), SVC_NAME,
                                 SERVICE_ALL_ACCESS));
    if (!schService)
    {
        LOG_WARN(("Could not open service.  (%d)", GetLastError()));
        return FALSE;
    }

    //Stop the service so it deletes faster and so the uninstaller
    // can actually delete its EXE.
    DWORD totalWaitTime = 0;
    SERVICE_STATUS status;
    static const int maxWaitTime = 1000 * 60; // Never wait more than a minute
    if (ControlService(schService.get(), SERVICE_CONTROL_STOP, &status))
    {
        do
        {
            Sleep(status.dwWaitHint);
            totalWaitTime += (status.dwWaitHint + 10);
            if (status.dwCurrentState == SERVICE_STOPPED)
            {
                break;
            }
            else if (totalWaitTime > maxWaitTime)
            {
                break;
            }
        }
        while (QueryServiceStatus(schService.get(), &status));
    }

    // Delete the service or mark it for deletion
    BOOL deleted = DeleteService(schService.get());
    if (!deleted)
    {
        deleted = (GetLastError() == ERROR_SERVICE_MARKED_FOR_DELETE);
    }

    return deleted;
}

/**
 * Sets the access control list for user access for the specified service.
 *
 * @param  hService The service to set the access control list on
 * @return TRUE if successful
 */
BOOL
SetUserAccessServiceDACL(SC_HANDLE hService)
{
    PACL pNewAcl = nullptr;
    PSECURITY_DESCRIPTOR psd = nullptr;
    DWORD lastError = SetUserAccessServiceDACL(hService, pNewAcl, psd);
    if (pNewAcl)
    {
        LocalFree((HLOCAL)pNewAcl);
    }
    if (psd)
    {
        LocalFree((LPVOID)psd);
    }
    return ERROR_SUCCESS == lastError;
}

/**
 * Sets the access control list for user access for the specified service.
 *
 * @param  hService  The service to set the access control list on
 * @param  pNewAcl   The out param ACL which should be freed by caller
 * @param  psd       out param security descriptor, should be freed by caller
 * @return ERROR_SUCCESS if successful
 */
DWORD
SetUserAccessServiceDACL(SC_HANDLE hService, PACL &pNewAcl,
                         PSECURITY_DESCRIPTOR psd)
{
    // Get the current security descriptor needed size
    DWORD needed = 0;
    if (!QueryServiceObjectSecurity(hService, DACL_SECURITY_INFORMATION,
                                    &psd, 0, &needed))
    {
        if (GetLastError() != ERROR_INSUFFICIENT_BUFFER)
        {
            LOG_WARN(("Could not query service object security size.  (%d)",
                      GetLastError()));
            return GetLastError();
        }

        DWORD size = needed;
        psd = (PSECURITY_DESCRIPTOR)LocalAlloc(LPTR, size);
        if (!psd)
        {
            LOG_WARN(("Could not allocate security descriptor.  (%d)",
                      GetLastError()));
            return ERROR_INSUFFICIENT_BUFFER;
        }

        // Get the actual security descriptor now
        if (!QueryServiceObjectSecurity(hService, DACL_SECURITY_INFORMATION,
                                        psd, size, &needed))
        {
            LOG_WARN(("Could not allocate security descriptor.  (%d)",
                      GetLastError()));
            return GetLastError();
        }
    }

    // Get the current DACL from the security descriptor.
    PACL pacl = nullptr;
    BOOL bDaclPresent = FALSE;
    BOOL bDaclDefaulted = FALSE;
    if ( !GetSecurityDescriptorDacl(psd, &bDaclPresent, &pacl,
                                    &bDaclDefaulted))
    {
        LOG_WARN(("Could not obtain DACL.  (%d)", GetLastError()));
        return GetLastError();
    }

    PSID sid;
    DWORD SIDSize = SECURITY_MAX_SID_SIZE;
    sid = LocalAlloc(LMEM_FIXED, SIDSize);
    if (!sid)
    {
        LOG_WARN(("Could not allocate SID memory.  (%d)", GetLastError()));
        return GetLastError();
    }

    if (!CreateWellKnownSid(WinBuiltinUsersSid, nullptr, sid, &SIDSize))
    {
        DWORD lastError = GetLastError();
        LOG_WARN(("Could not create well known SID.  (%d)", lastError));
        LocalFree(sid);
        return lastError;
    }

    // Lookup the account name, the function fails if you don't pass in
    // a buffer for the domain name but it's not used since we're using
    // the built in account Sid.
    SID_NAME_USE accountType;
    WCHAR accountName[UNLEN + 1] = { L'\0' };
    WCHAR domainName[DNLEN + 1] = { L'\0' };
    DWORD accountNameSize = UNLEN + 1;
    DWORD domainNameSize = DNLEN + 1;
    if (!LookupAccountSidW(nullptr, sid, accountName,
                           &accountNameSize,
                           domainName, &domainNameSize, &accountType))
    {
        LOG_WARN(("Could not lookup account Sid, will try Users.  (%d)",
                  GetLastError()));
        wcsncpy(accountName, L"Users", UNLEN);
    }

    // We already have the group name so we can get rid of the SID
    FreeSid(sid);
    sid = nullptr;

    // Build the ACE, BuildExplicitAccessWithName cannot fail so it is not logged.
    EXPLICIT_ACCESS ea;
    BuildExplicitAccessWithNameW(&ea, accountName,
                                 SERVICE_START | SERVICE_STOP | GENERIC_READ,
                                 SET_ACCESS, NO_INHERITANCE);
    DWORD lastError = SetEntriesInAclW(1, (PEXPLICIT_ACCESS)&ea, pacl, &pNewAcl);
    if (ERROR_SUCCESS != lastError)
    {
        LOG_WARN(("Could not set entries in ACL.  (%d)", lastError));
        return lastError;
    }

    // Initialize a new security descriptor.
    SECURITY_DESCRIPTOR sd;
    if (!InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION))
    {
        LOG_WARN(("Could not initialize security descriptor.  (%d)",
                  GetLastError()));
        return GetLastError();
    }

    // Set the new DACL in the security descriptor.
    if (!SetSecurityDescriptorDacl(&sd, TRUE, pNewAcl, FALSE))
    {
        LOG_WARN(("Could not set security descriptor DACL.  (%d)",
                  GetLastError()));
        return GetLastError();
    }

    // Set the new security descriptor for the service object.
    if (!SetServiceObjectSecurity(hService, DACL_SECURITY_INFORMATION, &sd))
    {
        LOG_WARN(("Could not set object security.  (%d)",
                  GetLastError()));
        return GetLastError();
    }

    // Woohoo, raise the roof
    LOG(("User access was set successfully on the service."));
    return ERROR_SUCCESS;
}