[Python-checkins] cpython (3.3): Issue #18805: better netmask validation in ipaddress
nick.coghlan
python-checkins at python.org
Sat Feb 8 14:21:14 CET 2014
http://hg.python.org/cpython/rev/ca5ea7c24370
changeset: 89043:ca5ea7c24370
branch: 3.3
parent: 89041:bd1d6916b689
user: Nick Coghlan <ncoghlan at gmail.com>
date: Sat Feb 08 23:17:36 2014 +1000
summary:
Issue #18805: better netmask validation in ipaddress
files:
Lib/ipaddress.py | 148 ++++++++++++++----------
Lib/test/test_ipaddress.py | 73 ++++++++---
Misc/NEWS | 3 +
3 files changed, 139 insertions(+), 85 deletions(-)
diff --git a/Lib/ipaddress.py b/Lib/ipaddress.py
--- a/Lib/ipaddress.py
+++ b/Lib/ipaddress.py
@@ -456,8 +456,8 @@
raise AddressValueError(msg % (address, address_len,
expected_len, self._version))
- def _ip_int_from_prefix(self, prefixlen=None):
- """Turn the prefix length netmask into a int for comparison.
+ def _ip_int_from_prefix(self, prefixlen):
+ """Turn the prefix length into a bitwise netmask
Args:
prefixlen: An integer, the prefix length.
@@ -466,36 +466,92 @@
An integer.
"""
- if prefixlen is None:
- prefixlen = self._prefixlen
return self._ALL_ONES ^ (self._ALL_ONES >> prefixlen)
- def _prefix_from_ip_int(self, ip_int, mask=32):
- """Return prefix length from the decimal netmask.
+ def _prefix_from_ip_int(self, ip_int):
+ """Return prefix length from the bitwise netmask.
Args:
- ip_int: An integer, the IP address.
- mask: The netmask. Defaults to 32.
+ ip_int: An integer, the netmask in axpanded bitwise format
Returns:
An integer, the prefix length.
+ Raises:
+ ValueError: If the input intermingles zeroes & ones
"""
- return mask - _count_righthand_zero_bits(ip_int, mask)
+ trailing_zeroes = _count_righthand_zero_bits(ip_int,
+ self._max_prefixlen)
+ prefixlen = self._max_prefixlen - trailing_zeroes
+ leading_ones = ip_int >> trailing_zeroes
+ all_ones = (1 << prefixlen) - 1
+ if leading_ones != all_ones:
+ byteslen = self._max_prefixlen // 8
+ details = ip_int.to_bytes(byteslen, 'big')
+ msg = 'Netmask pattern %r mixes zeroes & ones'
+ raise ValueError(msg % details)
+ return prefixlen
- def _ip_string_from_prefix(self, prefixlen=None):
- """Turn a prefix length into a dotted decimal string.
+ def _report_invalid_netmask(self, netmask_str):
+ msg = '%r is not a valid netmask' % netmask_str
+ raise NetmaskValueError(msg) from None
+
+ def _prefix_from_prefix_string(self, prefixlen_str):
+ """Return prefix length from a numeric string
Args:
- prefixlen: An integer, the netmask prefix length.
+ prefixlen_str: The string to be converted
Returns:
- A string, the dotted decimal netmask string.
+ An integer, the prefix length.
+ Raises:
+ NetmaskValueError: If the input is not a valid netmask
"""
- if not prefixlen:
- prefixlen = self._prefixlen
- return self._string_from_ip_int(self._ip_int_from_prefix(prefixlen))
+ # int allows a leading +/- as well as surrounding whitespace,
+ # so we ensure that isn't the case
+ if not _BaseV4._DECIMAL_DIGITS.issuperset(prefixlen_str):
+ self._report_invalid_netmask(prefixlen_str)
+ try:
+ prefixlen = int(prefixlen_str)
+ except ValueError:
+ self._report_invalid_netmask(prefixlen_str)
+ if not (0 <= prefixlen <= self._max_prefixlen):
+ self._report_invalid_netmask(prefixlen_str)
+ return prefixlen
+
+ def _prefix_from_ip_string(self, ip_str):
+ """Turn a netmask/hostmask string into a prefix length
+
+ Args:
+ ip_str: The netmask/hostmask to be converted
+
+ Returns:
+ An integer, the prefix length.
+
+ Raises:
+ NetmaskValueError: If the input is not a valid netmask/hostmask
+ """
+ # Parse the netmask/hostmask like an IP address.
+ try:
+ ip_int = self._ip_int_from_string(ip_str)
+ except AddressValueError:
+ self._report_invalid_netmask(ip_str)
+
+ # Try matching a netmask (this would be /1*0*/ as a bitwise regexp).
+ # Note that the two ambiguous cases (all-ones and all-zeroes) are
+ # treated as netmasks.
+ try:
+ return self._prefix_from_ip_int(ip_int)
+ except ValueError:
+ pass
+
+ # Invert the bits, and try matching a /0+1+/ hostmask instead.
+ ip_int ^= self._ALL_ONES
+ try:
+ return self._prefix_from_ip_int(ip_int)
+ except ValueError:
+ self._report_invalid_netmask(ip_str)
class _BaseAddress(_IPAddressBase):
@@ -504,7 +560,6 @@
This IP class contains the version independent methods which are
used by single IP addresses.
-
"""
def __init__(self, address):
@@ -873,7 +928,7 @@
raise ValueError('prefix length diff must be > 0')
new_prefixlen = self._prefixlen + prefixlen_diff
- if not self._is_valid_netmask(str(new_prefixlen)):
+ if new_prefixlen > self._max_prefixlen:
raise ValueError(
'prefix length diff %d is invalid for netblock %s' % (
new_prefixlen, self))
@@ -1428,33 +1483,16 @@
self.network_address = IPv4Address(self._ip_int_from_string(addr[0]))
if len(addr) == 2:
- mask = addr[1].split('.')
-
- if len(mask) == 4:
- # We have dotted decimal netmask.
- if self._is_valid_netmask(addr[1]):
- self.netmask = IPv4Address(self._ip_int_from_string(
- addr[1]))
- elif self._is_hostmask(addr[1]):
- self.netmask = IPv4Address(
- self._ip_int_from_string(addr[1]) ^ self._ALL_ONES)
- else:
- raise NetmaskValueError('%r is not a valid netmask'
- % addr[1])
-
- self._prefixlen = self._prefix_from_ip_int(int(self.netmask))
- else:
- # We have a netmask in prefix length form.
- if not self._is_valid_netmask(addr[1]):
- raise NetmaskValueError('%r is not a valid netmask'
- % addr[1])
- self._prefixlen = int(addr[1])
- self.netmask = IPv4Address(self._ip_int_from_prefix(
- self._prefixlen))
+ try:
+ # Check for a netmask in prefix length form
+ self._prefixlen = self._prefix_from_prefix_string(addr[1])
+ except NetmaskValueError:
+ # Check for a netmask or hostmask in dotted-quad form.
+ # This may raise NetmaskValueError.
+ self._prefixlen = self._prefix_from_ip_string(addr[1])
else:
self._prefixlen = self._max_prefixlen
- self.netmask = IPv4Address(self._ip_int_from_prefix(
- self._prefixlen))
+ self.netmask = IPv4Address(self._ip_int_from_prefix(self._prefixlen))
if strict:
if (IPv4Address(int(self.network_address) & int(self.netmask)) !=
@@ -2042,11 +2080,8 @@
self.network_address = IPv6Address(self._ip_int_from_string(addr[0]))
if len(addr) == 2:
- if self._is_valid_netmask(addr[1]):
- self._prefixlen = int(addr[1])
- else:
- raise NetmaskValueError('%r is not a valid netmask'
- % addr[1])
+ # This may raise NetmaskValueError
+ self._prefixlen = self._prefix_from_prefix_string(addr[1])
else:
self._prefixlen = self._max_prefixlen
@@ -2061,23 +2096,6 @@
if self._prefixlen == (self._max_prefixlen - 1):
self.hosts = self.__iter__
- def _is_valid_netmask(self, prefixlen):
- """Verify that the netmask/prefixlen is valid.
-
- Args:
- prefixlen: A string, the netmask in prefix length format.
-
- Returns:
- A boolean, True if the prefix represents a valid IPv6
- netmask.
-
- """
- try:
- prefixlen = int(prefixlen)
- except ValueError:
- return False
- return 0 <= prefixlen <= self._max_prefixlen
-
@property
def is_site_local(self):
"""Test if the address is reserved for site-local.
diff --git a/Lib/test/test_ipaddress.py b/Lib/test/test_ipaddress.py
--- a/Lib/test/test_ipaddress.py
+++ b/Lib/test/test_ipaddress.py
@@ -398,18 +398,47 @@
assertBadAddress("::1.2.3.4", "Only decimal digits")
assertBadAddress("1.2.3.256", re.escape("256 (> 255)"))
+ def test_valid_netmask(self):
+ self.assertEqual(str(self.factory('192.0.2.0/255.255.255.0')),
+ '192.0.2.0/24')
+ for i in range(0, 33):
+ # Generate and re-parse the CIDR format (trivial).
+ net_str = '0.0.0.0/%d' % i
+ net = self.factory(net_str)
+ self.assertEqual(str(net), net_str)
+ # Generate and re-parse the expanded netmask.
+ self.assertEqual(
+ str(self.factory('0.0.0.0/%s' % net.netmask)), net_str)
+ # Zero prefix is treated as decimal.
+ self.assertEqual(str(self.factory('0.0.0.0/0%d' % i)), net_str)
+ # Generate and re-parse the expanded hostmask. The ambiguous
+ # cases (/0 and /32) are treated as netmasks.
+ if i in (32, 0):
+ net_str = '0.0.0.0/%d' % (32 - i)
+ self.assertEqual(
+ str(self.factory('0.0.0.0/%s' % net.hostmask)), net_str)
+
def test_netmask_errors(self):
def assertBadNetmask(addr, netmask):
- msg = "%r is not a valid netmask"
- with self.assertNetmaskError(msg % netmask):
+ msg = "%r is not a valid netmask" % netmask
+ with self.assertNetmaskError(re.escape(msg)):
self.factory("%s/%s" % (addr, netmask))
assertBadNetmask("1.2.3.4", "")
+ assertBadNetmask("1.2.3.4", "-1")
+ assertBadNetmask("1.2.3.4", "+1")
+ assertBadNetmask("1.2.3.4", " 1 ")
+ assertBadNetmask("1.2.3.4", "0x1")
assertBadNetmask("1.2.3.4", "33")
assertBadNetmask("1.2.3.4", "254.254.255.256")
+ assertBadNetmask("1.2.3.4", "1.a.2.3")
assertBadNetmask("1.1.1.1", "254.xyz.2.3")
assertBadNetmask("1.1.1.1", "240.255.0.0")
+ assertBadNetmask("1.1.1.1", "255.254.128.0")
+ assertBadNetmask("1.1.1.1", "0.1.127.255")
assertBadNetmask("1.1.1.1", "pudding")
+ assertBadNetmask("1.1.1.1", "::")
+
class InterfaceTestCase_v4(BaseTestCase, NetmaskTestMixin_v4):
factory = ipaddress.IPv4Interface
@@ -438,17 +467,34 @@
assertBadAddress("10/8", "At least 3 parts")
assertBadAddress("1234:axy::b", "Only hex digits")
+ def test_valid_netmask(self):
+ # We only support CIDR for IPv6, because expanded netmasks are not
+ # standard notation.
+ self.assertEqual(str(self.factory('2001:db8::/32')), '2001:db8::/32')
+ for i in range(0, 129):
+ # Generate and re-parse the CIDR format (trivial).
+ net_str = '::/%d' % i
+ self.assertEqual(str(self.factory(net_str)), net_str)
+ # Zero prefix is treated as decimal.
+ self.assertEqual(str(self.factory('::/0%d' % i)), net_str)
+
def test_netmask_errors(self):
def assertBadNetmask(addr, netmask):
- msg = "%r is not a valid netmask"
- with self.assertNetmaskError(msg % netmask):
+ msg = "%r is not a valid netmask" % netmask
+ with self.assertNetmaskError(re.escape(msg)):
self.factory("%s/%s" % (addr, netmask))
assertBadNetmask("::1", "")
assertBadNetmask("::1", "::1")
assertBadNetmask("::1", "1::")
+ assertBadNetmask("::1", "-1")
+ assertBadNetmask("::1", "+1")
+ assertBadNetmask("::1", " 1 ")
+ assertBadNetmask("::1", "0x1")
assertBadNetmask("::1", "129")
+ assertBadNetmask("::1", "1.2.3.4")
assertBadNetmask("::1", "pudding")
+ assertBadNetmask("::", "::")
class InterfaceTestCase_v6(BaseTestCase, NetmaskTestMixin_v6):
factory = ipaddress.IPv6Interface
@@ -694,16 +740,14 @@
def testZeroNetmask(self):
ipv4_zero_netmask = ipaddress.IPv4Interface('1.2.3.4/0')
self.assertEqual(int(ipv4_zero_netmask.network.netmask), 0)
- self.assertTrue(ipv4_zero_netmask.network._is_valid_netmask(
- str(0)))
+ self.assertEqual(ipv4_zero_netmask._prefix_from_prefix_string('0'), 0)
self.assertTrue(ipv4_zero_netmask._is_valid_netmask('0'))
self.assertTrue(ipv4_zero_netmask._is_valid_netmask('0.0.0.0'))
self.assertFalse(ipv4_zero_netmask._is_valid_netmask('invalid'))
ipv6_zero_netmask = ipaddress.IPv6Interface('::1/0')
self.assertEqual(int(ipv6_zero_netmask.network.netmask), 0)
- self.assertTrue(ipv6_zero_netmask.network._is_valid_netmask(
- str(0)))
+ self.assertEqual(ipv6_zero_netmask._prefix_from_prefix_string('0'), 0)
def testIPv4NetAndHostmasks(self):
net = self.ipv4_network
@@ -719,7 +763,7 @@
self.assertFalse(net._is_hostmask('1.2.3.4'))
net = ipaddress.IPv4Network('127.0.0.0/0.0.0.255')
- self.assertEqual(24, net.prefixlen)
+ self.assertEqual(net.prefixlen, 24)
def testGetBroadcast(self):
self.assertEqual(int(self.ipv4_network.broadcast_address), 16909311)
@@ -1271,11 +1315,6 @@
self.assertEqual(ipaddress.IPv6Interface('::1:0:0:0:0').packed,
b'\x00' * 6 + b'\x00\x01' + b'\x00' * 8)
- def testIpStrFromPrefixlen(self):
- ipv4 = ipaddress.IPv4Interface('1.2.3.4/24')
- self.assertEqual(ipv4._ip_string_from_prefix(), '255.255.255.0')
- self.assertEqual(ipv4._ip_string_from_prefix(28), '255.255.255.240')
-
def testIpType(self):
ipv4net = ipaddress.ip_network('1.2.3.4')
ipv4addr = ipaddress.ip_address('1.2.3.4')
@@ -1467,14 +1506,8 @@
def testIPBases(self):
net = self.ipv4_network
self.assertEqual('1.2.3.0/24', net.compressed)
- self.assertEqual(
- net._ip_int_from_prefix(24),
- net._ip_int_from_prefix(None))
net = self.ipv6_network
self.assertRaises(ValueError, net._string_from_ip_int, 2**128 + 1)
- self.assertEqual(
- self.ipv6_address._string_from_ip_int(self.ipv6_address._ip),
- self.ipv6_address._string_from_ip_int(None))
def testIPv6NetworkHelpers(self):
net = self.ipv6_network
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -48,6 +48,9 @@
Library
-------
+- Issue #18805: the netmask/hostmask parsing in ipaddress now more reliably
+ filters out illegal values
+
- Issue #17369: get_filename was raising an exception if the filename
parameter's RFC2231 encoding was broken in certain ways. This was
a regression relative to python2.
--
Repository URL: http://hg.python.org/cpython
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