diff --git a/html/inc/consent.inc b/html/inc/consent.inc
index fda2b51b2d..94dead3b1c 100644
--- a/html/inc/consent.inc
+++ b/html/inc/consent.inc
@@ -48,7 +48,9 @@ function consent_to_a_policy(
 function check_user_consent($user, $consent_name) {
     list($checkct, $ctid) = check_consent_type($consent_name);
     if ($checkct) {
-        $consent_result = BoincLatestConsent::lookup("userid={$user->id} AND consent_type_id=$ctid AND consent_flag=1");
+        $consent_result = BoincLatestConsent::lookup(
+            "userid=$user->id AND consent_type_id=$ctid AND consent_flag=1"
+        );
         if ($consent_result) {
             return TRUE;
         }
@@ -64,7 +66,8 @@ function check_user_consent($user, $consent_name) {
 // If the boolean is FALSE, the integer returned is -1.
 //
 function check_consent_type($name, $checkenabled=TRUE) {
-    $ct = BoincConsentType::lookup("shortname = '{$name}'");
+    $name = BoincDb::escape_string($name);
+    $ct = BoincConsentType::lookup("shortname = '$name'");
     if ($ct and ( !$checkenabled or ($ct->enabled)) ) {
         return array(TRUE, $ct->id);
     }
diff --git a/html/inc/prefs_util.inc b/html/inc/prefs_util.inc
index 77ce73dd5f..4b2c6962d0 100644
--- a/html/inc/prefs_util.inc
+++ b/html/inc/prefs_util.inc
@@ -32,13 +32,13 @@ function check_venue($x) {
     if ($x == "home") return;
     if ($x == "work") return;
     if ($x == "school") return;
-    error_page(tra("bad venue: %1", $x));
+    error_page("bad venue");
 }
 
 function check_subset($x) {
     if ($x == "global") return;
     if ($x == "project") return;
-    error_page(tra("bad subset: %1", $x));
+    error_page("bad subset");
 }
 
 abstract class PREF {
@@ -281,7 +281,7 @@ class PREF_CONSENT extends PREF {
                 $user, $consent_type_id, $flag, 0, 'Webform', time()
             );
             if (!$rc) {
-                error_page(tra("Database error:").BoincDb::error());
+                error_page("Database error");
             }
         }
     }
@@ -300,7 +300,7 @@ class PREF_CONSENT extends PREF {
             $user, $consent_type_id, $this->default, 0, 'Webform'
         );
         if (!$rc) {
-            error_page(tra("Database error:").BoincDb::error());
+            error_page("Database error");
         }
     }
 
diff --git a/html/inc/user_util.inc b/html/inc/user_util.inc
index 4d9179bb27..be6694f689 100644
--- a/html/inc/user_util.inc
+++ b/html/inc/user_util.inc
@@ -211,7 +211,7 @@ function validate_post_make_user() {
         $team = BoincTeam::lookup_id($teamid);
         $clone_user = BoincUser::lookup_id($team->userid);
         if (!$clone_user) {
-            error_page("User $userid not found");
+            error_page("User $team->userid not found");
         }
         $project_prefs = $clone_user->project_prefs;
     } else {
diff --git a/html/inc/util.inc b/html/inc/util.inc
index b740c94cd4..ef5d98a04f 100644
--- a/html/inc/util.inc
+++ b/html/inc/util.inc
@@ -166,7 +166,11 @@ function send_cookie($name, $value, $permanent, $ops=false) {
         $path .= "_ops/";
     }
     $expire = $permanent?time()+3600*24*365:0;
-    setcookie($name, $value, $expire, $path);
+    setcookie($name, $value, $expire, $path,
+        '',
+        is_https(),     // if this page is secure, make cookie secure
+        true            // httponly; no JS access
+    );
 }
 
 function clear_cookie($name, $ops=false) {
@@ -887,10 +891,7 @@ function strip_bbcode($string){
 }
 
 function current_url() {
-    $url = "http";
-    if (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == "on") {
-        $url .= "s";
-    }
+    $url = is_https()?'https':'http';
     $url .= "://";
     $url .= $_SERVER['SERVER_NAME'];
     $url .= ":".$_SERVER['SERVER_PORT'];
@@ -1107,7 +1108,7 @@ function do_download($path) {
 function redirect_to_secure_url() {
     if (defined('SECURE_URL_BASE')
         && strstr(SECURE_URL_BASE, "https://")
-        && empty($_SERVER['HTTPS'])
+        && !is_https()
     ) {
         Header("Location: https://".$_SERVER['HTTP_HOST'].$_SERVER['REQUEST_URI']);
         exit;
diff --git a/html/inc/util_basic.inc b/html/inc/util_basic.inc
index 8785c24b11..754de0954d 100644
--- a/html/inc/util_basic.inc
+++ b/html/inc/util_basic.inc
@@ -200,6 +200,7 @@ function dtime() {
 // is $x a valid file (or dir) name?
 //
 function is_valid_filename($x) {
+    if (htmlspecialchars($x) != $x) return false;
     if (strstr($x, '/')) return false;
     return true;
 }
diff --git a/html/user/am_set_host_info.php b/html/user/am_set_host_info.php
index b05d4a6e2d..a99df5ed42 100644
--- a/html/user/am_set_host_info.php
+++ b/html/user/am_set_host_info.php
@@ -16,6 +16,8 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with BOINC.  If not, see <http://www.gnu.org/licenses/>.
 
+// Handler for RPC to change the venue of a host
+
 require_once("../inc/boinc_db.inc");
 require_once("../inc/xml.inc");
 
diff --git a/html/user/buda.php b/html/user/buda.php
index 0068293ebd..b3bfb9fa38 100644
--- a/html/user/buda.php
+++ b/html/user/buda.php
@@ -432,7 +432,7 @@ case 'view_file':
 case null:
     app_list(); break;
 default:
-    error_page("unknown action $action");
+    error_page("unknown action");
 }
 
 ?>
diff --git a/html/user/manage_app.php b/html/user/manage_app.php
index 5209e0fd69..67be6ca17c 100644
--- a/html/user/manage_app.php
+++ b/html/user/manage_app.php
@@ -208,6 +208,6 @@ case "batches_form":
 case "batches_action":
     batches_action($app); break;
 default:
-    error_page("unknown action $action");
+    error_page("unknown action");
 }
 ?>
diff --git a/html/user/manage_project.php b/html/user/manage_project.php
index a4780203b9..4e6a3a9554 100644
--- a/html/user/manage_project.php
+++ b/html/user/manage_project.php
@@ -208,7 +208,7 @@ case 'edit_form':
 case 'edit_action':
     handle_edit_action(); break;
 default:
-    error_page("unknown action: $action");
+    error_page("unknown action");
 }
 
 ?>
diff --git a/html/user/sandbox.php b/html/user/sandbox.php
index c687b92749..8ec96c6742 100644
--- a/html/user/sandbox.php
+++ b/html/user/sandbox.php
@@ -88,7 +88,7 @@ function list_files($user) {
     $dir = sandbox_dir($user);
     if (!is_dir($dir)) error_page("Can't open sandbox directory");
     page_head("File sandbox");
-    $notice = get_str('notice', true);
+    $notice = htmlspecialchars(get_str('notice', true));
     if ($notice) {
         echo "<p>$notice<hr>";
     }
@@ -197,6 +197,9 @@ function upload_file($user) {
 function add_file($user) {
     $dir = sandbox_dir($user);
     $name = post_str('name');
+    if (!is_valid_filename($name)) {
+        error_page('bad filename');
+    }
     if (!$name) error_page('No name given');
     if (file_exists("$dir/$name")) {
         error_page("file $name exists");
@@ -215,6 +218,9 @@ function add_file($user) {
 function get_file($user) {
     $dir = sandbox_dir($user);
     $url = post_str('url');
+    if (filter_var($url, FILTER_VALIDATE_URL) === FALSE) {
+        error_page('Not a valid URL');
+    }
     $fname = basename($url);
     $path = "$dir/$fname";
     if (file_exists($path)) {
@@ -229,6 +235,9 @@ function get_file($user) {
 //
 function delete_file($user) {
     $name = get_str('name');
+    if (!is_valid_filename($name)) {
+        error_page('bad filename');
+    }
     $dir = sandbox_dir($user);
     unlink("$dir/$name");
     unlink("$dir/.md5/$name");
@@ -238,16 +247,22 @@ function delete_file($user) {
 
 function download_file($user) {
     $name = get_str('name');
+    if (!is_valid_filename($name)) {
+        error_page('bad filename');
+    }
     $dir = sandbox_dir($user);
     do_download("$dir/$name");
 }
 
 function view_file($user) {
     $name = get_str('name');
+    if (!is_valid_filename($name)) {
+        error_page('bad filename');
+    }
     $dir = sandbox_dir($user);
     $path = "$dir/$name";
     if (!is_file($path)) {
-        error_path("no such file $name");
+        error_page("no such file");
     }
     echo "<pre>\n";
     readfile($path);
@@ -269,7 +284,7 @@ case 'delete_file': delete_file($user); break;
 case 'download_file': download_file($user); break;
 case 'view_file': view_file($user); break;
 case 'add_form': add_form($user); break;
-default: error_page("no such action: $action");
+default: error_page("no such action: ".htmlspecialchars($action));
 }
 
 ?>
diff --git a/html/user/team_forum.php b/html/user/team_forum.php
index 216ef8ba51..1e23bc64a9 100644
--- a/html/user/team_forum.php
+++ b/html/user/team_forum.php
@@ -205,7 +205,7 @@ if ($cmd == 'manage') {
     require_founder_login($user, $team);
     remove($team);
 } else if ($cmd != "") {
-    error_page("unknown command $cmd");
+    error_page("unknown command ".htmlspecialchars($cmd));
 } else {
     show_forum($team);
 }
diff --git a/html/user/team_founder_transfer_action.php b/html/user/team_founder_transfer_action.php
index 496e070175..9bffc5ee67 100644
--- a/html/user/team_founder_transfer_action.php
+++ b/html/user/team_founder_transfer_action.php
@@ -145,7 +145,7 @@ case "decline":
     }
     break;
 default:
-    error_page(tra("undefined action %1", $action));
+    error_page("undefined action ".htmlspecialchars($action));
 }
 
 echo "<a href='team_display.php?teamid=$team->id'>".tra("Return to team page")."</a>";