From 6700b93c4d7a16e7288e4e2cd3223093926666ea Mon Sep 17 00:00:00 2001 From: Andrey Andreev Date: Sat, 24 Sep 2011 14:25:33 +0300 Subject: Added _file_mime_type() method to system/libraries/Upload.php in order to fix a possible MIME-type injection (issue #60) --- system/libraries/Upload.php | 68 +++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 66 insertions(+), 2 deletions(-) (limited to 'system/libraries/Upload.php') diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php index 3177424c4..93f763ed9 100644 --- a/system/libraries/Upload.php +++ b/system/libraries/Upload.php @@ -196,7 +196,8 @@ class CI_Upload { // Set the uploaded data as class variables $this->file_temp = $_FILES[$field]['tmp_name']; $this->file_size = $_FILES[$field]['size']; - $this->file_type = preg_replace("/^(.+?);.*$/", "\\1", $_FILES[$field]['type']); + $this->_file_mime_type($_FILES[$field]); + $this->file_type = preg_replace("/^(.+?);.*$/", "\\1", $this->file_type); $this->file_type = strtolower(trim(stripslashes($this->file_type), '"')); $this->file_name = $this->_prep_filename($_FILES[$field]['name']); $this->file_ext = $this->get_extension($this->file_name); @@ -1006,8 +1007,71 @@ class CI_Upload { // -------------------------------------------------------------------- + /** + * File MIME type + * + * Detects the (actual) MIME type of the uploaded file, if possible. + * The input array is expected to be $_FILES[$field] + * + * @param array + * @return void + */ + protected function _file_mime_type($file) + { + $file_type = ''; + + // Use if the Fileinfo extension, if available (only versions above 5.3 support the FILEINFO_MIME_TYPE flag) + if ( (float) substr(phpversion(), 0, 3) >= 5.3 && function_exists('finfo_file')) + { + $finfo = new finfo(FILEINFO_MIME_TYPE); + if ($finfo !== FALSE) // This is possible, if there is no magic MIME database file found on the system + { + $file_type = $finfo->file($file['tmp_name']); + + /* According to the comments section of the PHP manual page, + * it is possible that this function returns an empty string + * for some files (e.g. if they don't exist in the magic MIME database. + */ + if (strlen($file_type) > 1) + { + $this->file_type = $file_info; + return; + } + } + } + + // Fall back to the deprecated mime_content_type(), if available + if (function_exists('mime_content_type')) + { + $this->file_type = @mime_content_type($file['tmp_name']); + return; + } + + /* This is an ugly hack, but UNIX-type systems provide a native way to detect the file type, + * which is still more secure than depending on the value of $_FILES[$field]['type']. + * + * Notes: + * - a 'W' in the substr() expression bellow, would mean that we're using Windows + * - many system admins would disable the exec() function due to security concerns, hence the function_exists() check + */ + if (substr(PHP_OS, 0, 1) !== 'W' && function_exists('exec')) + { + $output = array(); + @exec('file --brief --mime-type ' . escapeshellarg($file['tmp_path']), $output, $return_code); + if ($return_code === 0 && strlen($output[0]) > 0) // A return status code != 0 would mean failed execution + { + $this->file_type = rtrim($output[0]); + return; + } + } + + $this->file_type = $file['type']; + } + + // -------------------------------------------------------------------- + } // END Upload Class /* End of file Upload.php */ -/* Location: ./system/libraries/Upload.php */ \ No newline at end of file +/* Location: ./system/libraries/Upload.php */ -- cgit v1.2.3-24-g4f1b From 6a12d8faba9dcb4f321700c86d047f7b6a4f1780 Mon Sep 17 00:00:00 2001 From: Andrey Andreev Date: Sat, 24 Sep 2011 14:35:10 +0300 Subject: Remove an unnecessary variable initialization --- system/libraries/Upload.php | 2 -- 1 file changed, 2 deletions(-) (limited to 'system/libraries/Upload.php') diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php index 93f763ed9..04abc9ac6 100644 --- a/system/libraries/Upload.php +++ b/system/libraries/Upload.php @@ -1018,8 +1018,6 @@ class CI_Upload { */ protected function _file_mime_type($file) { - $file_type = ''; - // Use if the Fileinfo extension, if available (only versions above 5.3 support the FILEINFO_MIME_TYPE flag) if ( (float) substr(phpversion(), 0, 3) >= 5.3 && function_exists('finfo_file')) { -- cgit v1.2.3-24-g4f1b From 7bfb95b9c329a7905a20f9ebfeacccac7ffd7e41 Mon Sep 17 00:00:00 2001 From: Andrey Andreev Date: Sat, 24 Sep 2011 14:45:44 +0300 Subject: Fix alignment with tabs instead of spaces --- system/libraries/Upload.php | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'system/libraries/Upload.php') diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php index 04abc9ac6..fd9c8b3e8 100644 --- a/system/libraries/Upload.php +++ b/system/libraries/Upload.php @@ -1058,7 +1058,7 @@ class CI_Upload { @exec('file --brief --mime-type ' . escapeshellarg($file['tmp_path']), $output, $return_code); if ($return_code === 0 && strlen($output[0]) > 0) // A return status code != 0 would mean failed execution { - $this->file_type = rtrim($output[0]); + $this->file_type = rtrim($output[0]); return; } } -- cgit v1.2.3-24-g4f1b From f1649bf567aa769b283bb0b74ed8aee5b44a704b Mon Sep 17 00:00:00 2001 From: Andrey Andreev Date: Sat, 24 Sep 2011 22:59:37 +0300 Subject: Fix an erroneus variable name and a typo in comments --- system/libraries/Upload.php | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'system/libraries/Upload.php') diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php index fd9c8b3e8..a0f3e76bb 100644 --- a/system/libraries/Upload.php +++ b/system/libraries/Upload.php @@ -1028,11 +1028,11 @@ class CI_Upload { /* According to the comments section of the PHP manual page, * it is possible that this function returns an empty string - * for some files (e.g. if they don't exist in the magic MIME database. + * for some files (e.g. if they don't exist in the magic MIME database) */ if (strlen($file_type) > 1) { - $this->file_type = $file_info; + $this->file_type = $file_type; return; } } -- cgit v1.2.3-24-g4f1b From c5efd10679a7b7b4010cd6cc30bd976d3fe8c1ef Mon Sep 17 00:00:00 2001 From: Andrey Andreev Date: Tue, 4 Oct 2011 18:27:32 +0300 Subject: Change Windows OS detection approach --- system/libraries/Upload.php | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'system/libraries/Upload.php') diff --git a/system/libraries/Upload.php b/system/libraries/Upload.php index a0f3e76bb..05511b5d3 100644 --- a/system/libraries/Upload.php +++ b/system/libraries/Upload.php @@ -1052,7 +1052,7 @@ class CI_Upload { * - a 'W' in the substr() expression bellow, would mean that we're using Windows * - many system admins would disable the exec() function due to security concerns, hence the function_exists() check */ - if (substr(PHP_OS, 0, 1) !== 'W' && function_exists('exec')) + if (DIRECTORY_SEPARATOR !== '\\' && function_exists('exec')) { $output = array(); @exec('file --brief --mime-type ' . escapeshellarg($file['tmp_path']), $output, $return_code); -- cgit v1.2.3-24-g4f1b