7 files changed, 55 insertions, 9 deletions
diff --git a/system/core/Common.php b/system/core/Common.php
index fadc0a0b1..f8ab7e800 100644
--- a/system/core/Common.php
+++ b/system/core/Common.php
@@ -569,7 +569,7 @@ if ( ! function_exists('set_status_header'))
 			return;
 		}
 
-		$server_protocol = (isset($_SERVER['SERVER_PROTOCOL']) && in_array($_SERVER['SERVER_PROTOCOL'], array('HTTP/1.0', 'HTTP/1.1', 'HTTP/2'), TRUE))
+		$server_protocol = (isset($_SERVER['SERVER_PROTOCOL']) && in_array($_SERVER['SERVER_PROTOCOL'], array('HTTP/1.0', 'HTTP/1.1', 'HTTP/2', 'HTTP/2.0'), TRUE))
 			? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.1';
 		header($server_protocol.' '.$code.' '.$text, TRUE, $code);
 	}
diff --git a/system/database/DB_driver.php b/system/database/DB_driver.php
index b4f16b905..f3433f849 100644
--- a/system/database/DB_driver.php
+++ b/system/database/DB_driver.php
@@ -825,6 +825,18 @@ abstract class CI_DB_driver {
 	{
 		return $this->_trans_status;
 	}
+	
+	// --------------------------------------------------------------------
+
+	/**
+	 * Returns TRUE if a transaction is currently active
+	 *
+	 * @return	bool
+	 */
+	public function trans_active()
+	{
+		return (bool) $this->_trans_depth;
+	}
 
 	// --------------------------------------------------------------------
 
diff --git a/system/helpers/captcha_helper.php b/system/helpers/captcha_helper.php
index 642ff3a50..dcd6882c8 100644
--- a/system/helpers/captcha_helper.php
+++ b/system/helpers/captcha_helper.php
@@ -103,6 +103,18 @@ if ( ! function_exists('create_captcha'))
 			return FALSE;
 		}
 
+		if ($img_path === '' OR $img_url === '')
+		{
+			log_message('error', 'create_captcha(): $img_path and $img_url are required.');
+			return FALSE;
+		}
+
+		if ( ! is_dir($img_path) OR ! is_really_writable($img_path))
+		{
+			log_message('error', "create_captcha(): '{$img_path}' is not a dir, nor is it writable.");
+			return FALSE;
+		}
+
 		if ($img_url !== '' OR $img_path !== '')
 		{
 			if ($img_path === '' OR $img_url === '')
diff --git a/system/libraries/Cache/drivers/Cache_redis.php b/system/libraries/Cache/drivers/Cache_redis.php
index 9dbe52844..9b082d11b 100644
--- a/system/libraries/Cache/drivers/Cache_redis.php
+++ b/system/libraries/Cache/drivers/Cache_redis.php
@@ -77,6 +77,13 @@ class CI_Cache_redis extends CI_Driver
 	 */
 	protected static $_delete_name;
 
+	/**
+	 * sRem()/sRemove() method name depending on phpRedis version
+	 *
+	 * @var	string
+	 */
+	protected static $_sRemove_name;
+
 	// ------------------------------------------------------------------------
 
 	/**
@@ -98,9 +105,19 @@ class CI_Cache_redis extends CI_Driver
 			return;
 		}
 
-		isset(static::$_delete_name) OR static::$_delete_name = version_compare(phpversion('redis'), '5', '>=')
-			? 'del'
-			: 'delete';
+		if ( ! isset(static::$_delete_name, static::$_sRemove_name))
+		{
+			if (version_compare(phpversion('redis'), '5', '>='))
+			{
+				static::$_delete_name  = 'del';
+				static::$_sRemove_name = 'sRem';
+			}
+			else
+			{
+				static::$_delete_name  = 'delete';
+				static::$_sRemove_name = 'sRemove';
+			}
+		}
 
 		$CI =& get_instance();
 
@@ -210,7 +227,7 @@ class CI_Cache_redis extends CI_Driver
 		}
 		else
 		{
-			$this->_redis->sRemove('_ci_redis_serialized', $id);
+			$this->_redis->{static::$_sRemove_name}('_ci_redis_serialized', $id);
 		}
 
 		return TRUE;
@@ -231,7 +248,7 @@ class CI_Cache_redis extends CI_Driver
 			return FALSE;
 		}
 
-		$this->_redis->sRemove('_ci_redis_serialized', $key);
+		$this->_redis->{static::$_sRemove_name}('_ci_redis_serialized', $key);
 
 		return TRUE;
 	}
diff --git a/system/libraries/Session/drivers/Session_files_driver.php b/system/libraries/Session/drivers/Session_files_driver.php
index 2899b7dec..d9966273b 100644
--- a/system/libraries/Session/drivers/Session_files_driver.php
+++ b/system/libraries/Session/drivers/Session_files_driver.php
@@ -196,6 +196,10 @@ class CI_Session_files_driver extends CI_Session_driver implements SessionHandle
 				$this->_fingerprint = md5('');
 				return '';
 			}
+
+			// Prevent possible data corruption
+			// See https://github.com/bcit-ci/CodeIgniter/issues/5857
+			clearstatcache(TRUE, $this->_file_path.$session_id);
 		}
 		// We shouldn't need this, but apparently we do ...
 		// See https://github.com/bcit-ci/CodeIgniter/issues/4039
diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php
index 8c891cff6..95f765b78 100644
--- a/system/libraries/Upload.php
+++ b/system/libraries/Upload.php
@@ -867,7 +867,7 @@ class CI_Upload {
 			$this->file_type = 'image/jpeg';
 		}
 
-		$img_mimes = array('image/gif',	'image/jpeg', 'image/png');
+		$img_mimes = array('image/gif',	'image/jpeg', 'image/png', 'image/webp');
 
 		return in_array($this->file_type, $img_mimes, TRUE);
 	}
@@ -901,7 +901,7 @@ class CI_Upload {
 		}
 
 		// Images get some additional checks
-		if (in_array($ext, array('gif', 'jpg', 'jpeg', 'jpe', 'png'), TRUE) && @getimagesize($this->file_temp) === FALSE)
+		if (in_array($ext, array('gif', 'jpg', 'jpeg', 'jpe', 'png', 'webp'), TRUE) && @getimagesize($this->file_temp) === FALSE)
 		{
 			return FALSE;
 		}
diff --git a/system/libraries/Zip.php b/system/libraries/Zip.php
index 5fba1cf3a..4579e8c2b 100644
--- a/system/libraries/Zip.php
+++ b/system/libraries/Zip.php
@@ -406,13 +406,14 @@ class CI_Zip {
 			return FALSE;
 		}
 
+		// @see https://github.com/bcit-ci/CodeIgniter/issues/5864
 		$footer = $this->directory."\x50\x4b\x05\x06\x00\x00\x00\x00"
 			.pack('v', $this->entries) // total # of entries "on this disk"
 			.pack('v', $this->entries) // total # of entries overall
 			.pack('V', self::strlen($this->directory)) // size of central dir
 			.pack('V', self::strlen($this->zipdata)) // offset to start of central dir
 			."\x00\x00"; // .zip file comment length
-		return $this->zipdata . $footer;
+		return $this->zipdata.$footer;
 	}
 
 	// --------------------------------------------------------------------