Program: CWE-434
Project: CVE-2017-7695
Buggy source:
<?php
	/*
		Class: BigTreeStorage
			Facilitates the storage, deletion, and replacement of files (whether local or cloud stored).
	*/

	class BigTreeStorage {

		var $AutoJPEG = false;
		var $DisabledFileError = false;
		var $DisabledExtensionRegEx = '/\\.(exe|com|bat|php|rb|py|cgi|pl|sh|asp|aspx)$/i';
		var $Service = "";
		var $Cloud = false;
		var $Settings;

		/*
			Constructor:
				Retrieves the current desired service and image processing availability.
		*/

		function __construct() {
			global $cms;
			
			// Get by reference because we modify it.
			$this->Settings = &$cms->autoSaveSetting("bigtree-internal-storage");
			
			if (!empty($this->Settings->Service)) {
				if ($this->Settings->Service == "s3" || $this->Settings->Service == "amazon") {
					$this->Cloud = new BigTreeCloudStorage("amazon");
				} elseif ($this->Settings->Service == "rackspace") {
					$this->Cloud = new BigTreeCloudStorage("rackspace");
				} elseif ($this->Settings->Service == "google") {
					$this->Cloud = new BigTreeCloudStorage("google");
				}
			}
		}

		/*
			Function: convertJPEG
				Internal function for turning PNGs uploaded into JPG
		*/

		protected function convertJPEG($file,$name) {
			global $bigtree;

			// Try to figure out what this file is
			list($iwidth,$iheight,$itype,$iattr) = @getimagesize($file);

			if (($this->AutoJPEG || $bigtree["config"]["image_force_jpeg"]) && $itype == IMAGETYPE_PNG) {
				// See if this PNG has any alpha channels, if it does we're not doing a JPG conversion.
				$alpha = ord(@file_get_contents($file,null,null,25,1));
				if ($alpha != 4 && $alpha != 6) {
					// Convert the PNG to JPG
					$source = imagecreatefrompng($file);
					imagejpeg($source,$file,$bigtree["config"]["image_quality"]);
					imagedestroy($source);

					// If they originally uploaded a JPG we rotated into a PNG, we don't want to change the desired filename, but if they uploaded a PNG the new file should be JPG
					if (strtolower(substr($name,-3,3)) == "png") {
						$name = substr($name,0,-3)."jpg";
					}
				}
			}

			return $name;
		}

		/*
			Function: delete
				Deletes a file from the active storage service.

			Parameters:
				file_location - The URL of the file.
		*/

		function delete($file_location) {
			// Make sure we're using IPLs so we don't get it confused with cloud
			$file_location = str_replace(array(STATIC_ROOT,WWW_ROOT),array("{staticroot}","{wwwroot}"),$file_location);
			// Cloud
			if (substr($file_location,0,4) == "http" || substr($file_location,0,2) == "//") {
				// Try to get the container and pointer
				$parts = explode("/",$file_location);
				$domain = $parts[2];
				$container = $parts[3];
				$pointer_parts = array_slice($parts,4);
				if ($domain == "s3.amazonaws.com") {
					$service = "amazon";
				} elseif ($domain == "storage.googleapis.com") {
					$service = "google";
				} else {
					$service = "rackspace";
					// Need to figure out the actual container
					$container = false;
					$cloud = ($this->Settings->Service == $service) ? $this->Cloud : new BigTreeCloudStorage;
					foreach ($cloud->Settings["rackspace"]["container_cdn_urls"] as $c => $url) {
						if ($url == "http://$domain") {
							$container = $c;
						}
					}
					if (!$container) {
						return false;
					}
					$pointer_parts = array_slice($parts,3);
				}

				if ($this->Settings->Service == $service) {
					$pointer = implode("/",$pointer_parts);
					$this->Cloud->deleteFile($container,$pointer);
					if ($this->Settings->Container == $container) {
						sqlquery("DELETE FROM bigtree_caches WHERE `identifier` = 'org.bigtreecms.cloudfiles' AND `key` = '".sqlescape($pointer)."'");
					}
				} else {
					// We might have already made an instance for Rackspace
					$cloud = isset($cloud) ? $cloud : new BigTreeCloudStorage($service);
					$cloud->deleteFile($container,implode("/",$pointer_parts));
				}
			// Local
			} else {
				unlink(str_replace(array("{wwwroot}","{staticroot}"),SITE_ROOT,$file_location));
			}
		}

		/*
			Function: replace
				Stores a file to the current storage service and replaces any existing file with the same file_name.

			Parameters:
				local_file - The absolute path to the local file you wish to store.
				file_name - The file name at the storage end point.
				relative_path - The path (relative to SITE_ROOT or the bucket / container root) in which to store the file.
				remove_original - Whether to delete the local_file or not.

			Returns:
				The URL of the stored file.
		*/

		function replace($local_file,$file_name,$relative_path,$remove_original = true) {
			// Make sure there are no path exploits
			$file_name = BigTree::cleanFile($file_name);
			
			// If the file name ends in a disabled extension, fail.
			if (preg_match($this->DisabledExtensionRegEx, $file_name)) {
				$this->DisabledFileError = true;
				unlink($local_file);
				return false;
			}

			// If we're auto converting images to JPG from PNG
			$file_name = $this->convertJPEG($local_file,$file_name);
			// Enforce trailing slashe on relative_path
			$relative_path = $relative_path ? rtrim($relative_path,"/")."/" : "files/";

			if ($this->Cloud) {
				$success = $this->Cloud->uploadFile($local_file,$this->Settings->Container,$relative_path.$file_name,true);
				if ($success) {
					sqlquery("UPDATE bigtree_caches SET value = '".sqlescape(json_encode(array("name" => $file_name,"path" => $relative_path.$file_name,"size" => filesize($local_file))))."' WHERE `identifier` = 'org.bigtreecms.cloudfiles' AND `key` = '".sqlescape($relative_path.$file_name)."'");
				}
				if ($remove_original) {
					unlink($local_file);
				}
				return $success;
			} else {
				if ($remove_original) {
					$success = BigTree::moveFile($local_file,SITE_ROOT.$relative_path.$file_name);
				} else {
					$success = BigTree::copyFile($local_file,SITE_ROOT.$relative_path.$file_name);
				}
				if ($success) {
					return "{staticroot}".$relative_path.$file_name;
				} else {
					return false;
				}
			}
		}

		/*
			Function: store
				Stores a file to the current storage service and finds a unique filename if collisions exist.

			Parameters:
				local_file - The absolute path to the local file you wish to store.
				file_name - The desired file name at the storage end point.
				relative_path - The path (relative to SITE_ROOT or the bucket / container root) in which to store the file.
				remove_original - Whether to delete the local_file or not.
				prefixes - A list of file prefixes that also need to be accounted for when checking file name availability.

			Returns:
				The URL of the stored file.
		*/

		function store($local_file,$file_name,$relative_path,$remove_original = true,$prefixes = array()) {
			// Make sure there are no path exploits
			$file_name = BigTree::cleanFile($file_name);

			// If the file name ends in a disabled extension, fail.
			if (preg_match($this->DisabledExtensionRegEx, $file_name)) {
				$this->DisabledFileError = true;
				unlink($local_file);
				return false;
			}

			// If we're auto converting images to JPG from PNG
			$file_name = $this->convertJPEG($local_file,$file_name);
			// Enforce trailing slashe on relative_path
			$relative_path = $relative_path ? rtrim($relative_path,"/")."/" : "files/";

			if ($this->Cloud) {
				// Clean up the file name
				global $cms;
				$parts = BigTree::pathInfo($file_name);
				$clean_name = $cms->urlify($parts["filename"]);
				if (strlen($clean_name) > 50) {
					$clean_name = substr($clean_name,0,50);
				}
				// Best case name
				$file_name = $clean_name.".".strtolower($parts["extension"]);
				$x = 2;
				// Make sure we have a unique name
				while (!$file_name || sqlrows(sqlquery("SELECT `timestamp` FROM bigtree_caches WHERE `identifier` = 'org.bigtreecms.cloudfiles' AND `key` = '".sqlescape($relative_path.$file_name)."'"))) {
					$file_name = $clean_name."-$x.".strtolower($parts["extension"]);
					$x++;

					// Check all the prefixes, make sure they don't exist either
					if (is_array($prefixes) && count($prefixes)) {
						$prefix_query = array();
						foreach ($prefixes as $prefix) {
							$prefix_query[] = "`key` = '".sqlescape($relative_path.$prefix.$file_name)."'";
						}
						if (sqlrows(sqlquery("SELECT `timestamp` FROM bigtree_caches WHERE identifier = 'org.bigtreecms.cloudfiles' AND (".implode(" OR ",$prefix_query).")"))) {
							$file_name = false;
						}
					}
				}
				// Upload it
				$success = $this->Cloud->uploadFile($local_file,$this->Settings->Container,$relative_path.$file_name,true);
				if ($success) {
					sqlquery("INSERT INTO bigtree_caches (`identifier`,`key`,`value`) VALUES ('org.bigtreecms.cloudfiles','".sqlescape($relative_path.$file_name)."','".sqlescape(json_encode(array("name" => $file_name,"path" => $relative_path.$file_name,"size" => filesize($local_file))))."')");
				}
				if ($remove_original) {
					unlink($local_file);
				}
				return $success;
			} else {
				$safe_name = BigTree::getAvailableFileName(SITE_ROOT.$relative_path,$file_name,$prefixes);
				if ($remove_original) {
					$success = BigTree::moveFile($local_file,SITE_ROOT.$relative_path.$safe_name);
				} else {
					$success = BigTree::copyFile($local_file,SITE_ROOT.$relative_path.$safe_name);
				}
				if ($success) {
					return "{staticroot}".$relative_path.$safe_name;
				} else {
					return false;
				}
			}
		}
	}

	// Backwards compatibility
	class BigTreeUploadService extends BigTreeStorage {
		function upload($local_file,$file_name,$relative_path,$remove_original = true) {
			return $this->store($local_file,$file_name,$relative_path,$remove_original);
		}
	}

Fixed version (ground truth):
<?php
	/*
		Class: BigTreeStorage
			Facilitates the storage, deletion, and replacement of files (whether local or cloud stored).
	*/

	class BigTreeStorage {

		var $AutoJPEG = false;
		var $DisabledFileError = false;
		var $DisabledExtensionRegEx = '/\\.(exe|com|bat|php|rb|py|cgi|pl|sh|asp|aspx)/i';
		var $Service = "";
		var $Cloud = false;
		var $Settings;

		/*
			Constructor:
				Retrieves the current desired service and image processing availability.
		*/

		function __construct() {
			global $cms;
			
			// Get by reference because we modify it.
			$this->Settings = &$cms->autoSaveSetting("bigtree-internal-storage");
			
			if (!empty($this->Settings->Service)) {
				if ($this->Settings->Service == "s3" || $this->Settings->Service == "amazon") {
					$this->Cloud = new BigTreeCloudStorage("amazon");
				} elseif ($this->Settings->Service == "rackspace") {
					$this->Cloud = new BigTreeCloudStorage("rackspace");
				} elseif ($this->Settings->Service == "google") {
					$this->Cloud = new BigTreeCloudStorage("google");
				}
			}
		}

		/*
			Function: convertJPEG
				Internal function for turning PNGs uploaded into JPG
		*/

		protected function convertJPEG($file,$name) {
			global $bigtree;

			// Try to figure out what this file is
			list($iwidth,$iheight,$itype,$iattr) = @getimagesize($file);

			if (($this->AutoJPEG || $bigtree["config"]["image_force_jpeg"]) && $itype == IMAGETYPE_PNG) {
				// See if this PNG has any alpha channels, if it does we're not doing a JPG conversion.
				$alpha = ord(@file_get_contents($file,null,null,25,1));
				if ($alpha != 4 && $alpha != 6) {
					// Convert the PNG to JPG
					$source = imagecreatefrompng($file);
					imagejpeg($source,$file,$bigtree["config"]["image_quality"]);
					imagedestroy($source);

					// If they originally uploaded a JPG we rotated into a PNG, we don't want to change the desired filename, but if they uploaded a PNG the new file should be JPG
					if (strtolower(substr($name,-3,3)) == "png") {
						$name = substr($name,0,-3)."jpg";
					}
				}
			}

			return $name;
		}

		/*
			Function: delete
				Deletes a file from the active storage service.

			Parameters:
				file_location - The URL of the file.
		*/

		function delete($file_location) {
			// Make sure we're using IPLs so we don't get it confused with cloud
			$file_location = str_replace(array(STATIC_ROOT,WWW_ROOT),array("{staticroot}","{wwwroot}"),$file_location);
			// Cloud
			if (substr($file_location,0,4) == "http" || substr($file_location,0,2) == "//") {
				// Try to get the container and pointer
				$parts = explode("/",$file_location);
				$domain = $parts[2];
				$container = $parts[3];
				$pointer_parts = array_slice($parts,4);
				if ($domain == "s3.amazonaws.com") {
					$service = "amazon";
				} elseif ($domain == "storage.googleapis.com") {
					$service = "google";
				} else {
					$service = "rackspace";
					// Need to figure out the actual container
					$container = false;
					$cloud = ($this->Settings->Service == $service) ? $this->Cloud : new BigTreeCloudStorage;
					foreach ($cloud->Settings["rackspace"]["container_cdn_urls"] as $c => $url) {
						if ($url == "http://$domain") {
							$container = $c;
						}
					}
					if (!$container) {
						return false;
					}
					$pointer_parts = array_slice($parts,3);
				}

				if ($this->Settings->Service == $service) {
					$pointer = implode("/",$pointer_parts);
					$this->Cloud->deleteFile($container,$pointer);
					if ($this->Settings->Container == $container) {
						sqlquery("DELETE FROM bigtree_caches WHERE `identifier` = 'org.bigtreecms.cloudfiles' AND `key` = '".sqlescape($pointer)."'");
					}
				} else {
					// We might have already made an instance for Rackspace
					$cloud = isset($cloud) ? $cloud : new BigTreeCloudStorage($service);
					$cloud->deleteFile($container,implode("/",$pointer_parts));
				}
			// Local
			} else {
				unlink(str_replace(array("{wwwroot}","{staticroot}"),SITE_ROOT,$file_location));
			}
		}

		/*
			Function: replace
				Stores a file to the current storage service and replaces any existing file with the same file_name.

			Parameters:
				local_file - The absolute path to the local file you wish to store.
				file_name - The file name at the storage end point.
				relative_path - The path (relative to SITE_ROOT or the bucket / container root) in which to store the file.
				remove_original - Whether to delete the local_file or not.

			Returns:
				The URL of the stored file.
		*/

		function replace($local_file,$file_name,$relative_path,$remove_original = true) {
			// Make sure there are no path exploits
			$file_name = BigTree::cleanFile($file_name);
			
			// If the file name ends in a disabled extension, fail.
			if (preg_match($this->DisabledExtensionRegEx, $file_name)) {
				$this->DisabledFileError = true;
				unlink($local_file);
				return false;
			}

			// If we're auto converting images to JPG from PNG
			$file_name = $this->convertJPEG($local_file,$file_name);
			// Enforce trailing slashe on relative_path
			$relative_path = $relative_path ? rtrim($relative_path,"/")."/" : "files/";

			if ($this->Cloud) {
				$success = $this->Cloud->uploadFile($local_file,$this->Settings->Container,$relative_path.$file_name,true);
				if ($success) {
					sqlquery("UPDATE bigtree_caches SET value = '".sqlescape(json_encode(array("name" => $file_name,"path" => $relative_path.$file_name,"size" => filesize($local_file))))."' WHERE `identifier` = 'org.bigtreecms.cloudfiles' AND `key` = '".sqlescape($relative_path.$file_name)."'");
				}
				if ($remove_original) {
					unlink($local_file);
				}
				return $success;
			} else {
				if ($remove_original) {
					$success = BigTree::moveFile($local_file,SITE_ROOT.$relative_path.$file_name);
				} else {
					$success = BigTree::copyFile($local_file,SITE_ROOT.$relative_path.$file_name);
				}
				if ($success) {
					return "{staticroot}".$relative_path.$file_name;
				} else {
					return false;
				}
			}
		}

		/*
			Function: store
				Stores a file to the current storage service and finds a unique filename if collisions exist.

			Parameters:
				local_file - The absolute path to the local file you wish to store.
				file_name - The desired file name at the storage end point.
				relative_path - The path (relative to SITE_ROOT or the bucket / container root) in which to store the file.
				remove_original - Whether to delete the local_file or not.
				prefixes - A list of file prefixes that also need to be accounted for when checking file name availability.

			Returns:
				The URL of the stored file.
		*/

		function store($local_file,$file_name,$relative_path,$remove_original = true,$prefixes = array()) {
			// Make sure there are no path exploits
			$file_name = BigTree::cleanFile($file_name);

			// If the file name ends in a disabled extension, fail.
			if (preg_match($this->DisabledExtensionRegEx, $file_name)) {
				$this->DisabledFileError = true;
				unlink($local_file);
				return false;
			}

			// If we're auto converting images to JPG from PNG
			$file_name = $this->convertJPEG($local_file,$file_name);
			// Enforce trailing slashe on relative_path
			$relative_path = $relative_path ? rtrim($relative_path,"/")."/" : "files/";

			if ($this->Cloud) {
				// Clean up the file name
				global $cms;
				$parts = BigTree::pathInfo($file_name);
				$clean_name = $cms->urlify($parts["filename"]);
				if (strlen($clean_name) > 50) {
					$clean_name = substr($clean_name,0,50);
				}
				// Best case name
				$file_name = $clean_name.".".strtolower($parts["extension"]);
				$x = 2;
				// Make sure we have a unique name
				while (!$file_name || sqlrows(sqlquery("SELECT `timestamp` FROM bigtree_caches WHERE `identifier` = 'org.bigtreecms.cloudfiles' AND `key` = '".sqlescape($relative_path.$file_name)."'"))) {
					$file_name = $clean_name."-$x.".strtolower($parts["extension"]);
					$x++;

					// Check all the prefixes, make sure they don't exist either
					if (is_array($prefixes) && count($prefixes)) {
						$prefix_query = array();
						foreach ($prefixes as $prefix) {
							$prefix_query[] = "`key` = '".sqlescape($relative_path.$prefix.$file_name)."'";
						}
						if (sqlrows(sqlquery("SELECT `timestamp` FROM bigtree_caches WHERE identifier = 'org.bigtreecms.cloudfiles' AND (".implode(" OR ",$prefix_query).")"))) {
							$file_name = false;
						}
					}
				}
				// Upload it
				$success = $this->Cloud->uploadFile($local_file,$this->Settings->Container,$relative_path.$file_name,true);
				if ($success) {
					sqlquery("INSERT INTO bigtree_caches (`identifier`,`key`,`value`) VALUES ('org.bigtreecms.cloudfiles','".sqlescape($relative_path.$file_name)."','".sqlescape(json_encode(array("name" => $file_name,"path" => $relative_path.$file_name,"size" => filesize($local_file))))."')");
				}
				if ($remove_original) {
					unlink($local_file);
				}
				return $success;
			} else {
				$safe_name = BigTree::getAvailableFileName(SITE_ROOT.$relative_path,$file_name,$prefixes);
				if ($remove_original) {
					$success = BigTree::moveFile($local_file,SITE_ROOT.$relative_path.$safe_name);
				} else {
					$success = BigTree::copyFile($local_file,SITE_ROOT.$relative_path.$safe_name);
				}
				if ($success) {
					return "{staticroot}".$relative_path.$safe_name;
				} else {
					return false;
				}
			}
		}
	}

	// Backwards compatibility
	class BigTreeUploadService extends BigTreeStorage {
		function upload($local_file,$file_name,$relative_path,$remove_original = true) {
			return $this->store($local_file,$file_name,$relative_path,$remove_original);
		}
	}