Fix issue secdev#359

Handle ipv6 addresses according to RFC 5952
Add regression tests

scapy/pton_ntop.py

@@ -10,7 +10,7 @@
 without IPv6 support, on Windows for instance.
 """
 
-import socket,struct
+import socket,struct,re
 
 def inet_pton(af, addr):
  """Convert an IP address from text representation into binary form"""
@@ -77,25 +77,53 @@ def inet_ntop(af, addr):
  except AttributeError:
  pass
 
- # IPv6 addresses have 128bits (16 bytes)
- if len(addr) != 16:
+ return _ipv6_bin_to_str(addr)
+ else:
+ raise Exception("Address family not supported yet")
+
+
+def _ipv6_bin_to_str(addr):
+ # IPv6 addresses have 128bits (16 bytes)
+ if len(addr) != 16:
+ raise Exception("Illegal syntax for IP address")
+ parts = []
+ for left in [0, 2, 4, 6, 8, 10, 12, 14]:
+ try:
+ value = struct.unpack("!H", addr[left:left + 2])[0]
+ hexstr = hex(value)[2:]
+ except TypeError:
  raise Exception("Illegal syntax for IP address")
- parts = []
- for left in [0, 2, 4, 6, 8, 10, 12, 14]:
- try: 
- value = struct.unpack("!H", addr[left:left+2])[0]
- hexstr = hex(value)[2:]
- except TypeError:
- raise Exception("Illegal syntax for IP address")
- parts.append(hexstr.lstrip("0").lower())
- result = ":".join(parts)
- while ":::" in result:
- result = result.replace(":::", "::")
- # Leaving out leading and trailing zeros is only allowed with ::
- if result.endswith(":") and not result.endswith("::"):
- result = result + "0"
- if result.startswith(":") and not result.startswith("::"):
- result = "0" + result
- return result
+ parts.append(hexstr.lower())
+
+ address = ":".join(parts)
+
+ # Find all consecutive zero blocks
+ matches = re.findall('(?::|^)(0(?::0)+)(?::|$)', address)
+ if matches:
+ # If multiple consecutive blocks have the same length, take the leftmost
+ match = max(matches)
+ if address.startswith(match):
+ leftidx = 0
+ else:
+ leftidx = address.find(':' + match) + 1
+ left = address[:leftidx]
+ rightidx = leftidx + len(match)
+
+ # Adrress is like abcd:ef01::
+ if len(address) == rightidx:
+ compact_address = left + ":"
+
+ # Adrress is like ::abcd:ef01
+ elif leftidx == 0:
+ compact_address = ":" + address[rightidx:]
+
+ # Adrress is like abcd::ef01
+ else:
+ compact_address = left + address[rightidx:]
+
+ # Special case: address full of zeros
+ if compact_address == ":":
+ compact_address = "::"
  else:
- raise Exception("Address family not supported yet") 
+ compact_address = address
+ return compact_address

test/regression.uts

@@ -6897,3 +6897,66 @@ x = f.i2repr(mp, {'*', '+', 'bit 2'})
 assert(re.match(r'^.*Star \(\*\).*$', x) is not None)
 assert(re.match(r'^.*Plus \(\+\).*$', x) is not None)
 assert(re.match(r'^.*bit 2.*$', x) is not None)
+
+###########################################################################################################
++ Test correct conversion from binary to string of IPv6 addresses
+
+= IPv6 bin to string conversion - all zero bytes
+from scapy.pton_ntop import _ipv6_bin_to_str
+address=b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00' # All zero
+compressed = _ipv6_bin_to_str(address)
+assert(compressed == '::')
+
+= IPv6 bin to string conversion - non-compressable
+from scapy.pton_ntop import _ipv6_bin_to_str
+address=b'\x11\x11\x22\x22\x33\x33\x44\x44\x55\x55\x66\x66\x77\x77\x88\x88' # Not compressable
+compressed = _ipv6_bin_to_str(address)
+assert(compressed == '1111:2222:3333:4444:5555:6666:7777:8888')
+
+= IPv6 bin to string conversion - Zero-block right
+from scapy.pton_ntop import _ipv6_bin_to_str
+address=b'\x11\x11\x22\x22\x33\x33\x44\x44\x55\x55\x00\x00\x00\x00\x00\x00' # Zeroblock right
+compressed = _ipv6_bin_to_str(address)
+assert(compressed == '1111:2222:3333:4444:5555::')
+
+= IPv6 bin to string conversion - Zero-block left
+from scapy.pton_ntop import _ipv6_bin_to_str
+address=b'\x00\x00\x00\x00\x00\x00\x44\x44\x55\x55\x66\x66\x77\x77\x88\x88' # Zeroblock left
+compressed = _ipv6_bin_to_str(address)
+assert(compressed == '::4444:5555:6666:7777:8888')
+
+= IPv6 bin to string conversion - Two zero-block with different length
+from scapy.pton_ntop import _ipv6_bin_to_str
+address=b'\x00\x00\x00\x00\x33\x33\x44\x44\x00\x00\x00\x00\x00\x00\x88\x88' # Short and long zero block
+compressed = _ipv6_bin_to_str(address)
+assert(compressed == '0:0:3333:4444::8888')
+
+= IPv6 bin to string conversion - Address 1::
+from scapy.pton_ntop import _ipv6_bin_to_str
+address=b'\x00\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00' # only 1 on the left
+compressed = _ipv6_bin_to_str(address)
+assert(compressed == '1::')
+
+= IPv6 bin to string conversion - Address ::1
+from scapy.pton_ntop import _ipv6_bin_to_str
+address=b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01' # loopback
+compressed = _ipv6_bin_to_str(address)
+assert(compressed == '::1')
+
+= IPv6 bin to string conversion - Zero-block of length 1
+from scapy.pton_ntop import _ipv6_bin_to_str
+address=b'\x11\x11\x22\x22\x33\x33\x44\x44\x55\x55\x66\x66\x00\x00\x88\x88' # only one zero block
+compressed = _ipv6_bin_to_str(address)
+assert(compressed == '1111:2222:3333:4444:5555:6666:0:8888')
+
+= IPv6 bin to string conversion - Two zero-blocks with equal length
+from scapy.pton_ntop import _ipv6_bin_to_str
+address=b'\x11\x11\x00\x00\x00\x00\x44\x44\x00\x00\x00\x00\x77\x77\x88\x88' # two zero blocks of equal length
+compressed = _ipv6_bin_to_str(address)
+assert(compressed == '1111::4444:0:0:7777:8888')
+
+= IPv6 bin to string conversion - Leading zero suppression
+from scapy.pton_ntop import _ipv6_bin_to_str
+address=b'\x10\x00\x02\x00\x00\x30\x00\x04\x00\x05\x00\x60\x07\x00\x80\x00' # Leading zero suppression
+compressed = _ipv6_bin_to_str(address)
+assert(compressed == '1000:200:30:4:5:60:700:8000')