Changeset 56186

Timestamp:

07/10/2023 08:31:35 PM (3 years ago)

Author:

azaozz

Message:

Filesystem API: Ensure wp_tempnam() does not produce file names longer than 255 characters as this is the limit on most filesystems.

Props: costdev, doems, mikeschroder, oglekler, mrinal013.
Fixes: #35755.

Location:

trunk

Files:

• src/wp-admin/includes/file.php (modified) (1 diff)
• tests/phpunit/tests/file.php (modified) (1 diff)

trunk/src/wp-admin/includes/file.php

@@ -690 +690 @@
         $temp_filename .= '-' . wp_generate_password( 6, false );
         $temp_filename .= '.tmp';
-        $temp_filename  = $dir . wp_unique_filename( $dir, $temp_filename );
+        $temp_filename  = wp_unique_filename( $dir, $temp_filename );
+
+        /*
+         * Filesystems typically have a limit of 255 characters for a filename.
+         *
+         * If the generated unique filename exceeds this, truncate the initial
+         * filename and try again.
+         *
+         * As it's possible that the truncated filename may exist, producing a
+         * suffix of "-1" or "-10" which could exceed the limit again, truncate
+         * it to 252 instead.
+         */
+        $characters_over_limit = strlen( $temp_filename ) - 252;
+        if ( $characters_over_limit > 0 ) {
+                $filename = substr( $filename, 0, -$characters_over_limit );
+                return wp_tempnam( $filename, $dir );
+        }
+
+        $temp_filename = $dir . $temp_filename;
 
         $fp = @fopen( $temp_filename, 'x' );

trunk/tests/phpunit/tests/file.php

@@ -207 +207 @@
 
         /**
+         * Tests that `wp_tempnam()` limits the filename's length to 252 characters.
+         *
+         * @ticket 35755
+         *
+         * @covers ::wp_tempnam
+         *
+         * @dataProvider data_wp_tempnam_should_limit_filename_length_to_252_characters
+         */
+        public function test_wp_tempnam_should_limit_filename_length_to_252_characters( $filename ) {
+                $file = wp_tempnam( $filename );
+
+                if ( file_exists( $file ) ) {
+                        self::unlink( $file );
+                }
+
+                $this->assertLessThanOrEqual( 252, strlen( basename( $file ) ) );
+        }
+
+        /**
+         * Data provider.
+         *
+         * @return array[]
+         */
+        public function data_wp_tempnam_should_limit_filename_length_to_252_characters() {
+                return array(
+                        'the limit before adding characters for uniqueness' => array( 'filename' => str_pad( '', 241, 'filename' ) ),
+                        'one more than the limit before adding characters for uniqueness' => array( 'filename' => str_pad( '', 242, 'filename' ) ),
+                        '251 characters' => array( 'filename' => str_pad( '', 251, 'filename' ) ),
+                        '252 characters' => array( 'filename' => str_pad( '', 252, 'filename' ) ),
+                        '253 characters' => array( 'filename' => str_pad( '', 253, 'filename' ) ),
+                );
+        }
+
+        /**
+         * Tests that `wp_tempnam()` limits the filename's length to 252 characters
+         * when there is a name conflict.
+         *
+         * @ticket 35755
+         *
+         * @covers ::wp_tempnam
+         */
+        public function test_wp_tempnam_should_limit_filename_length_to_252_characters_with_name_conflict() {
+                // Create a conflict by removing the randomness of the generated password.
+                add_filter(
+                        'random_password',
+                        static function() {
+                                return '123456';
+                        },
+                        10,
+                        0
+                );
+
+                // A filename at the limit.
+                $filename = str_pad( '', 252, 'filename' );
+
+                // Create the initial file.
+                $existing_file = wp_tempnam( $filename );
+
+                // Try creating a file with the same name.
+                $actual = wp_tempnam( basename( $existing_file ) );
+
+                self::unlink( $existing_file );
+                self::unlink( $actual );
+
+                $this->assertLessThanOrEqual( 252, strlen( basename( $actual ) ) );
+        }
+
+        /**
+         * Tests that `wp_tempnam()` limits the filename's length to 252 characters
+         * when a 'random_password' filter returns passwords longer than 6 characters.
+         *
+         * @ticket 35755
+         *
+         * @covers ::wp_tempnam
+         */
+        public function test_wp_tempnam_should_limit_filename_length_to_252_characters_when_random_password_is_filtered() {
+                // Force random passwords to 12 characters.
+                add_filter(
+                        'random_password',
+                        static function() {
+                                return '1a2b3c4d5e6f';
+                        },
+                        10,
+                        0
+                );
+
+                // A filename at the limit.
+                $filename = str_pad( '', 252, 'filename' );
+                $actual   = wp_tempnam( $filename );
+
+                self::unlink( $actual );
+
+                $this->assertLessThanOrEqual( 252, strlen( basename( $actual ) ) );
+        }
+
+        /**
+         * Tests that `wp_tempnam()` limits the filename's length to 252 characters
+         * when a 'wp_unique_filename' filter returns a filename longer than 252 characters.
+         *
+         * @ticket 35755
+         *
+         * @covers ::wp_tempnam
+         */
+        public function test_wp_tempnam_should_limit_filename_length_to_252_characters_when_wp_unique_filename_is_filtered() {
+                // Determine the number of additional characters added by `wp_tempnam()`.
+                $temp_dir                    = get_temp_dir();
+                $additional_chars_filename   = wp_unique_filename( $temp_dir, 'filename' );
+                $additional_chars_generated  = wp_tempnam( $additional_chars_filename, $temp_dir );
+                $additional_chars_difference = strlen( basename( $additional_chars_generated ) ) - strlen( $additional_chars_filename );
+
+                $filenames_over_limit = 0;
+
+                // Make the filter send the filename over the limit.
+                add_filter(
+                        'wp_unique_filename',
+                        static function( $filename ) use ( &$filenames_over_limit ) {
+                                if ( strlen( $filename ) === 252 ) {
+                                        $filename .= '1';
+                                        ++$filenames_over_limit;
+                                }
+
+                                return $filename;
+                        },
+                        10,
+                        1
+                );
+
+                // A filename that will hit the limit when `wp_tempnam()` adds characters.
+                $filename = str_pad( '', 252 - $additional_chars_difference, 'filename' );
+                $actual   = wp_tempnam( $filename );
+
+                self::unlink( $additional_chars_generated );
+                self::unlink( $actual );
+
+                $this->assertLessThanOrEqual( 252, strlen( basename( $actual ) ), 'The final filename was over the limit.' );
+                $this->assertSame( 1, $filenames_over_limit, 'One filename should have been over the limit.' );
+        }
+
+        /**
+         * Tests that `wp_tempnam()` limits the filename's length to 252 characters
+         * when both a 'random_password' filter and a 'wp_unique_filename' filter
+         * cause the filename to be greater than 252 characters.
+         *
+         * @ticket 35755
+         *
+         * @covers ::wp_tempnam
+         */
+        public function test_wp_tempnam_should_limit_filename_length_to_252_characters_when_random_password_and_wp_unique_filename_are_filtered() {
+                // Force random passwords to 12 characters.
+                add_filter(
+                        'random_password',
+                        static function() {
+                                return '1a2b3c4d5e6f';
+                        },
+                        10,
+                        0
+                );
+
+                // Determine the number of additional characters added by `wp_tempnam()`.
+                $temp_dir                    = get_temp_dir();
+                $additional_chars_filename   = wp_unique_filename( $temp_dir, 'filename' );
+                $additional_chars_generated  = wp_tempnam( $additional_chars_filename, $temp_dir );
+                $additional_chars_difference = strlen( basename( $additional_chars_generated ) ) - strlen( $additional_chars_filename );
+
+                $filenames_over_limit = 0;
+
+                // Make the filter send the filename over the limit.
+                add_filter(
+                        'wp_unique_filename',
+                        static function( $filename ) use ( &$filenames_over_limit ) {
+                                if ( strlen( $filename ) === 252 ) {
+                                        $filename .= '1';
+                                        ++$filenames_over_limit;
+                                }
+
+                                return $filename;
+                        },
+                        10,
+                        1
+                );
+
+                // A filename that will hit the limit when `wp_tempnam()` adds characters.
+                $filename = str_pad( '', 252 - $additional_chars_difference, 'filename' );
+                $actual   = wp_tempnam( $filename );
+
+                self::unlink( $additional_chars_generated );
+                self::unlink( $actual );
+
+                $this->assertLessThanOrEqual( 252, strlen( basename( $actual ) ), 'The final filename was over the limit.' );
+                $this->assertSame( 1, $filenames_over_limit, 'One filename should have been over the limit.' );
+        }
+
+        /**
          * @ticket 47186
          */