Respect EOS when decoding HPACK.

Author: Lukasa

hyper/http20/huffman.py

@@ -66,6 +66,10 @@ def decode(self, encoded_string):
             for digit in number:
                 cur_node = cur_node.mapping[digit]
                 if cur_node.data is not None:
+                    # If we get EOS, everything else is padding.
+                    if cur_node.data > 255:
+                        break
+
                     decoded_message.append(cur_node.data)
                     cur_node = self.root
         except KeyError:

hyper/http20/huffman_constants.py

@@ -263,7 +263,8 @@
       0x3ffffd8,
       0x3ffffd9,
       0x3ffffda,
-      0x3ffffdb
+      0x3ffffdb,
+      0x3ffffdc,
 ]
 
 REQUEST_CODES_LENGTH = [
@@ -282,7 +283,8 @@
       26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
       26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
       26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
-      26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26
+      26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
+      26,
 ]
 
 RESPONSE_CODES = [
@@ -541,7 +543,8 @@
       0xffffd9,
       0xffffda,
       0xffffdb,
-      0xffffdc
+      0xffffdc,
+      0xffffdd,
 ]
 
 RESPONSE_CODES_LENGTH = [
@@ -560,6 +563,6 @@
       24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
       24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
       24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
-      24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24
+      24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
+      24,
 ]
-

test/test_huffman.py

@@ -32,3 +32,10 @@ def test_response_huffman_encode():
     assert encoder.encode(b"https://www.example.com") == (b'\xe3\x9e\x78\x64\xdd\x7a\xfd\x3d\x3d\x24\x87\x47\xdb\x87\x28\x49\x55\xf6\xff')
     assert encoder.encode(b"foo=ASDJKHQKBZXOQWEOPIUAXQWEOIU; max-age=3600; version=1") == (b'\xdf\x7d\xfb\x36\xd3\xd9\xe1\xfc\xfc\x3f\xaf\xe7\xab\xfc\xfe\xfc\xbf\xaf\x3e\xdf\x2f\x97\x7f\xd3\x6f\xf7\xfd\x79\xf6\xf9\x77\xfd\x3d\xe1\x6b\xfa\x46\xfe\x10\xd8\x89\x44\x7d\xe1\xce\x18\xe5\x65\xf7\x6c\x2f')
 
+def test_eos_terminates_decode_response():
+    decoder = HuffmanDecoder(RESPONSE_CODES,RESPONSE_CODES_LENGTH)
+    assert decoder.decode(b'\xff\xff\xdd\xff\xff\xff') == b''
+
+def test_eos_terminates_decode_request():
+    decoder = HuffmanDecoder(REQUEST_CODES,REQUEST_CODES_LENGTH)
+    assert decoder.decode(b'\xff\xff\xf7\x00') == b''