#1956 - Escape LIKE queries (for _ and %).

In MySQL queries, _ and % characters are treated as wildcards (similar to ? and *, respectively).
- Added escape_for_like function to MY_Database.php
- Added unit test to Database_Test
- Corrected the five unescaped instances in the code using this function.

2 files changed, 12 insertions, 2 deletions

diff --git a/modules/gallery/libraries/MY_Database.php b/modules/gallery/libraries/MY_Database.php
index aae0bb79..33759b67 100644
--- a/modules/gallery/libraries/MY_Database.php
+++ b/modules/gallery/libraries/MY_Database.php
@@ -88,4 +88,14 @@ abstract class Database extends Database_Core {
   static function set_default_instance($db) {
     self::$instances["default"] = $db;
   }
+
+  /**
+   * Escape LIKE queries, add wildcards.  In MySQL queries using LIKE, _ and % characters are
+   * treated as wildcards similar to ? and *, respectively.  Therefore, we need to escape _, %,
+   * and \ (the escape character itself).
+   */
+  static function escape_for_like($value) {
+    // backslash must go first to avoid double-escaping
+    return addcslashes($value, '\_%');
+  }
 }
\ No newline at end of file
diff --git a/modules/gallery/libraries/drivers/Cache/Database.php b/modules/gallery/libraries/drivers/Cache/Database.php
index a7aae92c..8790d0e1 100644
--- a/modules/gallery/libraries/drivers/Cache/Database.php
+++ b/modules/gallery/libraries/drivers/Cache/Database.php
@@ -69,7 +69,7 @@ class Cache_Database_Driver extends Cache_Driver {
       ->select()
       ->from("caches");
     foreach ($tags as $tag) {
-      $db->where("tags", "LIKE", "%<$tag>%");
+      $db->where("tags", "LIKE", "%" . Database::escape_for_like("<$tag>") . "%");
     }
     $db_result = $db->execute();
 
@@ -139,7 +139,7 @@ class Cache_Database_Driver extends Cache_Driver {
       // Delete all caches
     } else if ($is_tag === true) {
       foreach ($keys as $tag) {
-        $db->where("tags", "LIKE", "%<$tag>%");
+        $db->where("tags", "LIKE", "%" . Database::escape_for_like("<$tag>") . "%");
       }
     } else {
       $db->where("key", "IN", $keys);