Changeset 25541

Timestamp:

09/21/2013 06:53:50 AM (11 years ago)

Author:

dd32

Message:

When using download_url(), if the resource supplies a Content-MD5 header, verify the downloaded file against it. Fixes #20074

File:

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

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

@@ -486 +486 @@
     }
 
+    $content_md5 = wp_remote_retrieve_header( $response, 'content-md5' );
+    if ( $content_md5 ) {
+        $md5_check = verify_file_md5( $tmpfname, $content_md5 );
+        if ( is_wp_error( $md5_check ) ) {
+            unlink( $tmpfname );
+            return $md5_check;
+        }
+    }
+
     return $tmpfname;
+}
+
+/**
+ * Calculates and compares the MD5 of a file to it's expected value.
+ *
+ * @since 3.7.0
+ *
+ * @param string $filename The filename to check the MD5 of.
+ * @param string $expected_md5 The expected MD5 of the file, either a base64 encoded raw md5, or a hex-encoded md5
+ * @return bool|object WP_Error on failure, true on success, false when the MD5 format is unknown/unexpected
+ */
+function verify_file_md5( $filename, $expected_md5 ) {
+    if ( 32 == strlen( $expected_md5 ) )
+        $expected_raw_md5 = pack( 'H*', $expected_md5 );
+    elseif ( 24 == strlen( $expected_md5 ) )
+        $expected_raw_md5 = base64_decode( $expected_md5 );
+    else
+        return false; // unknown format
+
+    $file_md5 = md5_file( $filename, true );
+
+    if ( $file_md5 === $expected_raw_md5 )
+        return true;
+
+    return new WP_Error( 'md5_mismatch', sprintf( __( 'The checksum of the file (%1$s) does not match the expected checksum value (%2$s).' ), bin2hex( $file_md5 ), bin2hex( $expected_raw_md5 ) ) );
 }