Ticket #22952: 22952.diff

wp-includes/class-http.php

@@ -1653 +1653 @@
                 if ( empty($compressed) )
                         return $compressed;
 
-                if ( false !== ( $decompressed = @gzinflate( $compressed ) ) )
-                        return $decompressed;
-
                 if ( false !== ( $decompressed = WP_Http_Encoding::compatible_gzinflate( $compressed ) ) )
                         return $decompressed;
 
@@ -1694 +1691 @@
          */
         public static function compatible_gzinflate($gzData) {
 
-                // Compressed data might contain a full header, if so strip it for gzinflate()
+                // Compressed data might contain a full zlib header, if so strip it for gzinflate()
                 if ( substr($gzData, 0, 3) == "\x1f\x8b\x08" ) {
                         $i = 10;
                         $flg = ord( substr($gzData, 3, 1) );
@@ -1715 +1712 @@
                                 return $decompressed;
                 }
 
-                // Compressed data from java.util.zip.Deflater amongst others.
-                $decompressed = @gzinflate( substr($gzData, 2) );
-                if ( false !== $decompressed )
+                // If the data is Huffman Encoded, we must first strip the leading 2 byte Huffman marker for gzinflate()
+                // The Response is Huffman coded by many compressors such as java.util.zip.Deflater,
+                // Ruby’s Zlib::Deflate, and .NET's System.IO.Compression.DeflateStream.
+                // See http://decompres.blogspot.com/ for a quick explanation of this data type
+                $huffman_encoded = false;
+                list( $first_nibble ) = unpack( 'h', $gzData[0] ); // low nibble of first byte should be 0x08
+                list( $first_two_bytes ) = unpack( 'n', substr( $gzData, 0, 2 ) ); // First 2 bytes should be divisible by 0x1F
+                if ( 0x08 == $first_nibble && 0 == ( $first_two_bytes % 0x1F ) )
+                        $huffman_encoded = true;
+
+                if ( $huffman_encoded ) {
+                        if ( false !== ( $decompressed = @gzinflate( substr( $gzData, 2 ) ) ) )
+                                return $decompressed;
+                }
+
+                // Finally fall back to straight gzinflate
+                if ( false !== ( $decompressed = @gzinflate( $gzData ) ) )
                         return $decompressed;
 
+                // Fallback for all above failing, not expected, but included for debugging and preventing regressions
+                if ( false !== ( $decompressed = @gzinflate( substr( $gzData, 2 ) ) ) )
+                        return $decompressed;
+
                 return false;
         }