Index: src/__phutil_library_map__.php
===================================================================
--- src/__phutil_library_map__.php
+++ src/__phutil_library_map__.php
@@ -1202,6 +1202,8 @@
     'PhabricatorAuthProviderPassword' => 'applications/auth/provider/PhabricatorAuthProviderPassword.php',
     'PhabricatorAuthProviderPersona' => 'applications/auth/provider/PhabricatorAuthProviderPersona.php',
     'PhabricatorAuthRegisterController' => 'applications/auth/controller/PhabricatorAuthRegisterController.php',
+    'PhabricatorAuthSession' => 'applications/auth/storage/PhabricatorAuthSession.php',
+    'PhabricatorAuthSessionQuery' => 'applications/auth/query/PhabricatorAuthSessionQuery.php',
     'PhabricatorAuthStartController' => 'applications/auth/controller/PhabricatorAuthStartController.php',
     'PhabricatorAuthUnlinkController' => 'applications/auth/controller/PhabricatorAuthUnlinkController.php',
     'PhabricatorAuthValidateController' => 'applications/auth/controller/PhabricatorAuthValidateController.php',
@@ -1915,6 +1917,7 @@
     'PhabricatorSettingsPanelPassword' => 'applications/settings/panel/PhabricatorSettingsPanelPassword.php',
     'PhabricatorSettingsPanelSSHKeys' => 'applications/settings/panel/PhabricatorSettingsPanelSSHKeys.php',
     'PhabricatorSettingsPanelSearchPreferences' => 'applications/settings/panel/PhabricatorSettingsPanelSearchPreferences.php',
+    'PhabricatorSettingsPanelSessions' => 'applications/settings/panel/PhabricatorSettingsPanelSessions.php',
     'PhabricatorSetupCheck' => 'applications/config/check/PhabricatorSetupCheck.php',
     'PhabricatorSetupCheckAPC' => 'applications/config/check/PhabricatorSetupCheckAPC.php',
     'PhabricatorSetupCheckAuth' => 'applications/config/check/PhabricatorSetupCheckAuth.php',
@@ -3760,6 +3763,12 @@
     'PhabricatorAuthProviderPassword' => 'PhabricatorAuthProvider',
     'PhabricatorAuthProviderPersona' => 'PhabricatorAuthProvider',
     'PhabricatorAuthRegisterController' => 'PhabricatorAuthController',
+    'PhabricatorAuthSession' =>
+    array(
+      0 => 'PhabricatorAuthDAO',
+      1 => 'PhabricatorPolicyInterface',
+    ),
+    'PhabricatorAuthSessionQuery' => 'PhabricatorCursorPagedPolicyAwareQuery',
     'PhabricatorAuthStartController' => 'PhabricatorAuthController',
     'PhabricatorAuthUnlinkController' => 'PhabricatorAuthController',
     'PhabricatorAuthValidateController' => 'PhabricatorAuthController',
@@ -4548,6 +4557,7 @@
     'PhabricatorSettingsPanelPassword' => 'PhabricatorSettingsPanel',
     'PhabricatorSettingsPanelSSHKeys' => 'PhabricatorSettingsPanel',
     'PhabricatorSettingsPanelSearchPreferences' => 'PhabricatorSettingsPanel',
+    'PhabricatorSettingsPanelSessions' => 'PhabricatorSettingsPanel',
     'PhabricatorSetupCheckAPC' => 'PhabricatorSetupCheck',
     'PhabricatorSetupCheckAuth' => 'PhabricatorSetupCheck',
     'PhabricatorSetupCheckBaseURI' => 'PhabricatorSetupCheck',
Index: src/applications/auth/query/PhabricatorAuthSessionQuery.php
===================================================================
--- /dev/null
+++ src/applications/auth/query/PhabricatorAuthSessionQuery.php
@@ -0,0 +1,73 @@
+<?php
+
+final class PhabricatorAuthSessionQuery
+  extends PhabricatorCursorPagedPolicyAwareQuery {
+
+  private $identityPHIDs;
+
+  public function withIdentityPHIDs(array $identity_phids) {
+    $this->identityPHIDs = $identity_phids;
+    return $this;
+  }
+
+  protected function loadPage() {
+    $table = new PhabricatorAuthSession();
+    $conn_r = $table->establishConnection('r');
+
+    $data = queryfx_all(
+      $conn_r,
+      'SELECT * FROM %T %Q %Q %Q',
+      $table->getTableName(),
+      $this->buildWhereClause($conn_r),
+      $this->buildOrderClause($conn_r),
+      $this->buildLimitClause($conn_r));
+
+    return $table->loadAllFromArray($data);
+  }
+
+  protected function willFilterPage(array $sessions) {
+    $identity_phids = mpull($sessions, 'getUserPHID');
+
+    $identity_objects = id(new PhabricatorObjectQuery())
+      ->setViewer($this->getViewer())
+      ->setParentQuery($this)
+      ->withPHIDs($identity_phids)
+      ->execute();
+    $identity_objects = mpull($identity_objects, null, 'getPHID');
+
+    foreach ($sessions as $key => $session) {
+      $identity_object = idx($identity_objects, $session->getUserPHID());
+      if (!$identity_object) {
+        unset($sessions[$key]);
+      } else {
+        $session->attachIdentityObject($identity_object);
+      }
+    }
+
+    return $sessions;
+  }
+
+  protected function buildWhereClause(AphrontDatabaseConnection $conn_r) {
+    $where = array();
+
+    if ($this->identityPHIDs) {
+      $where[] = qsprintf(
+        $conn_r,
+        'userPHID IN (%Ls)',
+        $this->identityPHIDs);
+    }
+
+    $where[] = $this->buildPagingClause($conn_r);
+
+    return $this->formatWhereClause($where);
+  }
+
+  public function getPagingColumn() {
+    return 'sessionKey';
+  }
+
+  public function getQueryApplicationClass() {
+    return 'PhabricatorApplicationAuth';
+  }
+
+}
Index: src/applications/auth/storage/PhabricatorAuthSession.php
===================================================================
--- /dev/null
+++ src/applications/auth/storage/PhabricatorAuthSession.php
@@ -0,0 +1,72 @@
+<?php
+
+final class PhabricatorAuthSession extends PhabricatorAuthDAO
+  implements PhabricatorPolicyInterface {
+
+  protected $userPHID;
+  protected $type;
+  protected $sessionKey;
+  protected $sessionStart;
+
+  private $identityObject = self::ATTACHABLE;
+
+  public function getConfiguration() {
+    return array(
+      self::CONFIG_IDS => self::IDS_MANUAL,
+      self::CONFIG_TIMESTAMPS => false,
+    ) + parent::getConfiguration();
+  }
+
+  public function getApplicationName() {
+    // This table predates the "Auth" application, and really all applications.
+    return 'user';
+  }
+
+  public function getTableName() {
+    // This is a very old table with a nonstandard name.
+    return PhabricatorUser::SESSION_TABLE;
+  }
+
+  public function attachIdentityObject($identity_object) {
+    $this->identityObject = $identity_object;
+    return $this;
+  }
+
+  public function getIdentityObject() {
+    return $this->assertAttached($this->identityObject);
+  }
+
+
+/* -(  PhabricatorPolicyInterface  )----------------------------------------- */
+
+
+  public function getCapabilities() {
+    return array(
+      PhabricatorPolicyCapability::CAN_VIEW,
+    );
+  }
+
+  public function getPolicy($capability) {
+    return PhabricatorPolicies::POLICY_NOONE;
+  }
+
+  public function hasAutomaticCapability($capability, PhabricatorUser $viewer) {
+    if (!$viewer->getPHID()) {
+      return false;
+    }
+
+    $object = $this->getIdentityObject();
+    if ($object instanceof PhabricatorUser) {
+      return ($object->getPHID() == $viewer->getPHID());
+    } else if ($object instanceof PhabricatorExternalAccount) {
+      return ($object->getUserPHID() == $viewer->getPHID());
+    }
+
+    return false;
+  }
+
+  public function describeAutomaticCapability($capability) {
+    return pht('A session is visible only to its owner.');
+  }
+
+}
Index: src/applications/base/controller/PhabricatorController.php
===================================================================
--- src/applications/base/controller/PhabricatorController.php
+++ src/applications/base/controller/PhabricatorController.php
@@ -44,7 +44,7 @@
           'SELECT u.* FROM %T u JOIN %T s ON u.phid = s.userPHID
             AND s.type LIKE %> AND s.sessionKey = %s',
           $user->getTableName(),
-          'phabricator_session',
+          PhabricatorUser::SESSION_TABLE,
           'web-',
           PhabricatorHash::digest($phsid));
         if ($info) {
Index: src/applications/settings/panel/PhabricatorSettingsPanelSessions.php
===================================================================
--- /dev/null
+++ src/applications/settings/panel/PhabricatorSettingsPanelSessions.php
@@ -0,0 +1,95 @@
+<?php
+
+final class PhabricatorSettingsPanelSessions
+  extends PhabricatorSettingsPanel {
+
+  public function getPanelKey() {
+    return 'sessions';
+  }
+
+  public function getPanelName() {
+    return pht('Sessions');
+  }
+
+  public function getPanelGroup() {
+    return pht('Authentication');
+  }
+
+  public function isEnabled() {
+    return true;
+  }
+
+  public function processRequest(AphrontRequest $request) {
+    $viewer = $request->getUser();
+
+    $accounts = id(new PhabricatorExternalAccountQuery())
+      ->setViewer($viewer)
+      ->withUserPHIDs(array($viewer->getPHID()))
+      ->execute();
+
+    $identity_phids = mpull($accounts, 'getPHID');
+    $identity_phids[] = $viewer->getPHID();
+
+    $sessions = id(new PhabricatorAuthSessionQuery())
+      ->setViewer($viewer)
+      ->withIdentityPHIDs($identity_phids)
+      ->execute();
+
+    $handles = id(new PhabricatorHandleQuery())
+      ->setViewer($viewer)
+      ->withPHIDs($identity_phids)
+      ->execute();
+
+    // TODO: Once this has a real ID column, use that instead.
+    $sessions = msort($sessions, 'getSessionStart');
+    $sessions = array_reverse($sessions);
+
+    $current_key = PhabricatorHash::digest($request->getCookie('phsid'));
+
+    $rows = array();
+    $rowc = array();
+    foreach ($sessions as $session) {
+      if ($session->getSessionKey() == $current_key) {
+        $rowc[] = 'highlighted';
+      } else {
+        $rowc[] = null;
+      }
+
+      $rows[] = array(
+        $handles[$session->getUserPHID()]->renderLink(),
+        substr($session->getSessionKey(), 0, 12),
+        $session->getType(),
+        phabricator_datetime($session->getSessionStart(), $viewer),
+      );
+    }
+
+    $table = new AphrontTableView($rows);
+    $table->setNoDataString(pht("You don't have any active sessions."));
+    $table->setRowClasses($rowc);
+    $table->setHeaders(
+      array(
+        pht('Identity'),
+        pht('Session'),
+        pht('Type'),
+        pht('Created'),
+      ));
+    $table->setColumnClasses(
+      array(
+        'wide',
+        'n',
+        '',
+        'right',
+      ));
+
+
+    $header = id(new PHUIHeaderView())
+      ->setHeader(pht('Active Login Sessions'));
+
+    $panel = id(new PHUIObjectBoxView())
+      ->setHeader($header)
+      ->appendChild($table);
+
+    return $panel;
+  }
+
+}