Changeset 52269 for trunk/src/wp-admin/includes/image.php

Timestamp:

11/29/2021 07:34:51 PM (3 years ago)

Author:

hellofromTonya

Message:

Media: Fix TypeError and improve wp_exif_frac2dec() to only return int or float.

For certain images, wp_exif_frac2dec() unexpectedly returned a string instead of int or float. This can occur when an image is missing meta and calls the function with '0/0'. For those images, a fatal error was thrown on PHP 8.0+:

TypeError: round(): Argument #1 ($num) must be of type int|float, string given

Upon deeper review, inconsistent and unexpected results were returned from different types of input values passed to the function.

Changes are:

• Maintains backwards-compatibility for valid input values.
• Fixes handling of invalid input values by bailing out to return the documented type of int|float by returning 0.
• Improves the fractional conditional check.
• Improves the calculated fraction handling to ensure (a) the numerator and denominator are both numeric and (b) the denominator is not equal to zero.
• Safeguards the behavior via tests for all possible ways code could flow through the function.
• Safeguards the backwards-compatibility of the wp_read_image_metadata() by adding some defensive coding around the calls to the wp_exif_frac2dec() function.

These changes fix the fatal error and make the function more secure, stable, and predictable while maintaining backwards-compatibility for valid input values.

Follow-up to [6313], [9119], [22319], [28367], [45611], [47287].

Props adamsilverstein, jrf, peterwilsoncc, praem90, stevegs, tobiasbg.
Fixes #54385.

File:

• trunk/src/wp-admin/includes/image.php (modified) (4 diffs)

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

@@ -647 +647 @@
  * @since 2.5.0
  *
- * @param string $str
- * @return int|float
+ * @param string $str Fraction string.
+ * @return int|float Returns calculated fraction or integer 0 on invalid input.
  */
 function wp_exif_frac2dec( $str ) {
-    if ( false === strpos( $str, '/' ) ) {
-        return $str;
+    if ( ! is_scalar( $str ) || is_bool( $str ) ) {
+        return 0;
+    }
+
+    if ( ! is_string( $str ) ) {
+        return $str; // This can only be an integer or float, so this is fine.
+    }
+
+    // Fractions passed as a string must contain a single `/`.
+    if ( substr_count( $str, '/' ) !== 1 ) {
+        if ( is_numeric( $str ) ) {
+            return (float) $str;
+        }
+
+        return 0;
     }
 
     list( $numerator, $denominator ) = explode( '/', $str );
-    if ( ! empty( $denominator ) ) {
-        return $numerator / $denominator;
-    }
-    return $str;
+
+    // Both the numerator and the denominator must be numbers.
+    if ( ! is_numeric( $numerator ) || ! is_numeric( $denominator ) ) {
+        return 0;
+    }
+
+    // The denominator must not be zero.
+    if ( 0 == $denominator ) { // phpcs:ignore WordPress.PHP.StrictComparisons.LooseComparison -- Deliberate loose comparison.
+        return 0;
+    }
+
+    return $numerator / $denominator;
 }
 
@@ -841 +862 @@
             $meta['copyright'] = trim( $exif['Copyright'] );
         }
-        if ( ! empty( $exif['FNumber'] ) ) {
+        if ( ! empty( $exif['FNumber'] ) && is_scalar( $exif['FNumber'] ) ) {
             $meta['aperture'] = round( wp_exif_frac2dec( $exif['FNumber'] ), 2 );
         }
@@ -851 +872 @@
         }
         if ( ! empty( $exif['FocalLength'] ) ) {
-            $meta['focal_length'] = (string) wp_exif_frac2dec( $exif['FocalLength'] );
+            $meta['focal_length'] = (string) $exif['FocalLength'];
+            if ( is_scalar( $exif['FocalLength'] ) ) {
+                $meta['focal_length'] = (string) wp_exif_frac2dec( $exif['FocalLength'] );
+            }
         }
         if ( ! empty( $exif['ISOSpeedRatings'] ) ) {
@@ -858 +882 @@
         }
         if ( ! empty( $exif['ExposureTime'] ) ) {
-            $meta['shutter_speed'] = (string) wp_exif_frac2dec( $exif['ExposureTime'] );
+            $meta['shutter_speed'] = (string) $exif['ExposureTime'];
+            if ( is_scalar( $exif['ExposureTime'] ) ) {
+                $meta['shutter_speed'] = (string) wp_exif_frac2dec( $exif['ExposureTime'] );
+            }
         }
         if ( ! empty( $exif['Orientation'] ) ) {