Changeset 56186

Timestamp:

07/10/2023 08:31:35 PM (15 months 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
      */