/usr/share/pyshared/stem/util/connection.py is in python-stem 1.1.0-1.
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# See LICENSE for licensing information
"""
Connection and networking based utility functions.
::
get_connections - quieries the connections belonging to a given process
get_system_resolvers - provides connection resolution methods that are likely to be available
is_valid_ipv4_address - checks if a string is a valid IPv4 address
is_valid_ipv6_address - checks if a string is a valid IPv6 address
is_valid_port - checks if something is a valid representation for a port
is_private_address - checks if an IPv4 address belongs to a private range or not
expand_ipv6_address - provides an IPv6 address with its collapsed portions expanded
get_mask_ipv4 - provides the mask representation for a given number of bits
get_mask_ipv6 - provides the IPv6 mask representation for a given number of bits
.. data:: Resolver (enum)
Method for resolving a process' connections.
================= ===========
Resolver Description
================= ===========
**PROC** /proc contents
**NETSTAT** netstat command
**SS** ss command
**LSOF** lsof command
**SOCKSTAT** sockstat command under *nix
**BSD_SOCKSTAT** sockstat command under FreeBSD
**BSD_PROCSTAT** procstat command under FreeBSD
================= ===========
"""
import collections
import hashlib
import hmac
import os
import platform
import re
import stem.util.proc
import stem.util.system
from stem.util import enum, log
# Connection resolution is risky to log about since it's highly likely to
# contain sensitive information. That said, it's also difficult to get right in
# a platform independent fashion. To opt into the logging requried to
# troubleshoot connection resolution set the following...
LOG_CONNECTION_RESOLUTION = False
Resolver = enum.Enum(
('PROC', 'proc'),
('NETSTAT', 'netstat'),
('SS', 'ss'),
('LSOF', 'lsof'),
('SOCKSTAT', 'sockstat'),
('BSD_SOCKSTAT', 'sockstat (bsd)'),
('BSD_PROCSTAT', 'procstat (bsd)')
)
Connection = collections.namedtuple('Connection', [
'local_address',
'local_port',
'remote_address',
'remote_port',
'protocol',
])
FULL_IPv4_MASK = "255.255.255.255"
FULL_IPv6_MASK = "FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF"
CRYPTOVARIABLE_EQUALITY_COMPARISON_NONCE = os.urandom(32)
RESOLVER_COMMAND = {
Resolver.PROC: '',
# -n = prevents dns lookups, -p = include process
Resolver.NETSTAT: 'netstat -np',
# -n = numeric ports, -p = include process, -t = tcp sockets, -u = udp sockets
Resolver.SS: 'ss -nptu',
# -n = prevent dns lookups, -P = show port numbers (not names), -i = ip only, -w = no warnings
# (lsof provides a '-p <pid>' but oddly in practice it seems to be ~11-28% slower)
Resolver.LSOF: 'lsof -wnPi',
Resolver.SOCKSTAT: 'sockstat',
# -4 = IPv4, -c = connected sockets
Resolver.BSD_SOCKSTAT: 'sockstat -4c',
# -f <pid> = process pid
Resolver.BSD_PROCSTAT: 'procstat -f {pid}',
}
RESOLVER_FILTER = {
Resolver.PROC: '',
# tcp 0 586 192.168.0.1:44284 38.229.79.2:443 ESTABLISHED 15843/tor
Resolver.NETSTAT: '^{protocol}\s+.*\s+{local_address}:{local_port}\s+{remote_address}:{remote_port}\s+ESTABLISHED\s+{pid}/{name}\s*$',
# tcp ESTAB 0 0 192.168.0.20:44415 38.229.79.2:443 users:(("tor",15843,9))
Resolver.SS: '^{protocol}\s+ESTAB\s+.*\s+{local_address}:{local_port}\s+{remote_address}:{remote_port}\s+users:\(\("{name}",{pid},[0-9]+\)\)$',
# tor 3873 atagar 45u IPv4 40994 0t0 TCP 10.243.55.20:45724->194.154.227.109:9001 (ESTABLISHED)
Resolver.LSOF: '^{name}\s+{pid}\s+.*\s+{protocol}\s+{local_address}:{local_port}->{remote_address}:{remote_port} \(ESTABLISHED\)$',
# atagar tor 15843 tcp4 192.168.0.20:44092 68.169.35.102:443 ESTABLISHED
Resolver.SOCKSTAT: '^\S+\s+{name}\s+{pid}\s+{protocol}4\s+{local_address}:{local_port}\s+{remote_address}:{remote_port}\s+ESTABLISHED$',
# _tor tor 4397 12 tcp4 172.27.72.202:54011 127.0.0.1:9001
Resolver.BSD_SOCKSTAT: '^\S+\s+{name}\s+{pid}\s+\S+\s+{protocol}4\s+{local_address}:{local_port}\s+{remote_address}:{remote_port}$',
# 3561 tor 4 s - rw---n-- 2 0 TCP 10.0.0.2:9050 10.0.0.1:22370
Resolver.BSD_PROCSTAT: '^\s*{pid}\s+{name}\s+.*\s+{protocol}\s+{local_address}:{local_port}\s+{remote_address}:{remote_port}$',
}
def get_connections(resolver, process_pid = None, process_name = None):
"""
Retrieves a list of the current connections for a given process. The provides
a list of Connection instances, which have four attributes...
* local_address (str)
* local_port (int)
* remote_address (str)
* remote_port (int)
* protocol (str, generally either 'tcp' or 'udp')
:param Resolver resolver: method of connection resolution to use
:param int process_pid: pid of the process to retrieve
:param str process_name: name of the process to retrieve
:raises:
* **ValueError** if using **Resolver.PROC** or **Resolver.BSD_PROCSTAT**
and the process_pid wasn't provided
* **IOError** if no connections are available or resolution fails
(generally they're indistinguishable). The common causes are the
command being unavailable or permissions.
"""
def _log(msg):
if LOG_CONNECTION_RESOLUTION:
log.debug(msg)
_log("=" * 80)
_log("Querying connections for resolver: %s, pid: %s, name: %s" % (resolver, process_pid, process_name))
if isinstance(process_pid, str):
try:
process_pid = int(process_pid)
except ValueError:
raise ValueError("Process pid was non-numeric: %s" % process_pid)
if process_pid is None and resolver in (Resolver.PROC, Resolver.BSD_PROCSTAT):
raise ValueError("%s resolution requires a pid" % resolver)
if resolver == Resolver.PROC:
return [Connection(*conn) for conn in stem.util.proc.get_connections(process_pid)]
resolver_command = RESOLVER_COMMAND[resolver].format(pid = process_pid)
try:
results = stem.util.system.call(resolver_command)
except OSError as exc:
raise IOError("Unable to query '%s': %s" % (resolver_command, exc))
resolver_regex_str = RESOLVER_FILTER[resolver].format(
protocol = '(?P<protocol>\S+)',
local_address = '(?P<local_address>[0-9.]+)',
local_port = '(?P<local_port>[0-9]+)',
remote_address = '(?P<remote_address>[0-9.]+)',
remote_port = '(?P<remote_port>[0-9]+)',
pid = process_pid if process_pid else '[0-9]*',
name = process_name if process_name else '\S*',
)
_log("Resolver regex: %s" % resolver_regex_str)
_log("Resolver results:\n%s" % '\n'.join(results))
connections = []
resolver_regex = re.compile(resolver_regex_str)
for line in results:
match = resolver_regex.match(line)
if match:
attr = match.groupdict()
local_addr = attr['local_address']
local_port = int(attr['local_port'])
remote_addr = attr['remote_address']
remote_port = int(attr['remote_port'])
protocol = attr['protocol'].lower()
if remote_addr == '0.0.0.0':
continue # procstat response for unestablished connections
if not (is_valid_ipv4_address(local_addr) and is_valid_ipv4_address(remote_addr)):
_log("Invalid address (%s or %s): %s" % (local_addr, remote_addr, line))
elif not (is_valid_port(local_port) and is_valid_port(remote_port)):
_log("Invalid port (%s or %s): %s" % (local_port, remote_port, line))
elif protocol not in ('tcp', 'udp'):
_log("Unrecognized protocol (%s): %s" % (protocol, line))
conn = Connection(local_addr, local_port, remote_addr, remote_port, protocol)
connections.append(conn)
_log(str(conn))
_log("%i connections found" % len(connections))
if not connections:
raise IOError("No results found using: %s" % resolver_command)
return connections
def get_system_resolvers(system = None):
"""
Provides the types of connection resolvers likely to be available on this platform.
:param str system: system to get resolvers for, this is determined by
platform.system() if not provided
:returns: **list** of Resolvers likely to be available on this platform
"""
if system is None:
system = platform.system()
if system == 'Windows':
resolvers = []
elif system in ('Darwin', 'OpenBSD'):
resolvers = [Resolver.LSOF]
elif system == 'FreeBSD':
# Netstat is available, but lacks a '-p' equivilant so we can't associate
# the results to processes. The platform also has a ss command, but it
# belongs to a spreadsheet application.
resolvers = [Resolver.BSD_SOCKSTAT, Resolver.BSD_PROCSTAT, Resolver.LSOF]
else:
# Sockstat isn't available by default on ubuntu.
resolvers = [Resolver.NETSTAT, Resolver.SOCKSTAT, Resolver.LSOF, Resolver.SS]
# remove any that aren't in the user's PATH
resolvers = filter(lambda r: stem.util.system.is_available(RESOLVER_COMMAND[r]), resolvers)
# proc resolution, by far, outperforms the others so defaults to this is able
if stem.util.proc.is_available():
resolvers = [Resolver.PROC] + resolvers
return resolvers
def is_valid_ipv4_address(address):
"""
Checks if a string is a valid IPv4 address.
:param str address: string to be checked
:returns: **True** if input is a valid IPv4 address, **False** otherwise
"""
if not isinstance(address, (bytes, unicode)):
return False
# checks if theres four period separated values
if address.count(".") != 3:
return False
# checks that each value in the octet are decimal values between 0-255
for entry in address.split("."):
if not entry.isdigit() or int(entry) < 0 or int(entry) > 255:
return False
elif entry[0] == "0" and len(entry) > 1:
return False # leading zeros, for instance in "1.2.3.001"
return True
def is_valid_ipv6_address(address, allow_brackets = False):
"""
Checks if a string is a valid IPv6 address.
:param str address: string to be checked
:param bool allow_brackets: ignore brackets which form '[address]'
:returns: **True** if input is a valid IPv6 address, **False** otherwise
"""
if allow_brackets:
if address.startswith("[") and address.endswith("]"):
address = address[1:-1]
# addresses are made up of eight colon separated groups of four hex digits
# with leading zeros being optional
# https://en.wikipedia.org/wiki/IPv6#Address_format
colon_count = address.count(":")
if colon_count > 7:
return False # too many groups
elif colon_count != 7 and not "::" in address:
return False # not enough groups and none are collapsed
elif address.count("::") > 1 or ":::" in address:
return False # multiple groupings of zeros can't be collapsed
for entry in address.split(":"):
if not re.match("^[0-9a-fA-f]{0,4}$", entry):
return False
return True
def is_valid_port(entry, allow_zero = False):
"""
Checks if a string or int is a valid port number.
:param list,str,int entry: string, integer or list to be checked
:param bool allow_zero: accept port number of zero (reserved by definition)
:returns: **True** if input is an integer and within the valid port range, **False** otherwise
"""
if isinstance(entry, list):
for port in entry:
if not is_valid_port(port, allow_zero):
return False
return True
elif isinstance(entry, (bytes, unicode)):
if not entry.isdigit():
return False
elif entry[0] == "0" and len(entry) > 1:
return False # leading zeros, ex "001"
entry = int(entry)
if allow_zero and entry == 0:
return True
return entry > 0 and entry < 65536
def is_private_address(address):
"""
Checks if the IPv4 address is in a range belonging to the local network or
loopback. These include:
* Private ranges: 10.*, 172.16.* - 172.31.*, 192.168.*
* Loopback: 127.*
:param str address: string to be checked
:returns: **True** if input is in a private range, **False** otherwise
:raises: **ValueError** if the address isn't a valid IPv4 address
"""
if not is_valid_ipv4_address(address):
raise ValueError("'%s' isn't a valid IPv4 address" % address)
# checks for any of the simple wildcard ranges
if address.startswith("10.") or address.startswith("192.168.") or address.startswith("127."):
return True
# checks for the 172.16.* - 172.31.* range
if address.startswith("172."):
second_octet = int(address.split('.')[1])
if second_octet >= 16 and second_octet <= 31:
return True
return False
def expand_ipv6_address(address):
"""
Expands abbreviated IPv6 addresses to their full colon separated hex format.
For instance...
::
>>> expand_ipv6_address("2001:db8::ff00:42:8329")
"2001:0db8:0000:0000:0000:ff00:0042:8329"
>>> expand_ipv6_address("::")
"0000:0000:0000:0000:0000:0000:0000:0000"
:param str address: IPv6 address to be expanded
:raises: **ValueError** if the address can't be expanded due to being malformed
"""
if not is_valid_ipv6_address(address):
raise ValueError("'%s' isn't a valid IPv6 address" % address)
# expands collapsed groupings, there can only be a single '::' in a valid
# address
if "::" in address:
missing_groups = 7 - address.count(":")
address = address.replace("::", "::" + ":" * missing_groups)
# inserts missing zeros
for index in xrange(8):
start = index * 5
end = address.index(":", start) if index != 7 else len(address)
missing_zeros = 4 - (end - start)
if missing_zeros > 0:
address = address[:start] + "0" * missing_zeros + address[start:]
return address
def get_mask_ipv4(bits):
"""
Provides the IPv4 mask for a given number of bits, in the dotted-quad format.
:param int bits: number of bits to be converted
:returns: **str** with the subnet mask representation for this many bits
:raises: **ValueError** if given a number of bits outside the range of 0-32
"""
if bits > 32 or bits < 0:
raise ValueError("A mask can only be 0-32 bits, got %i" % bits)
elif bits == 32:
return FULL_IPv4_MASK
# get the binary representation of the mask
mask_bin = _get_binary(2 ** bits - 1, 32)[::-1]
# breaks it into eight character groupings
octets = [mask_bin[8 * i:8 * (i + 1)] for i in xrange(4)]
# converts each octet into its integer value
return ".".join([str(int(octet, 2)) for octet in octets])
def get_mask_ipv6(bits):
"""
Provides the IPv6 mask for a given number of bits, in the hex colon-delimited
format.
:param int bits: number of bits to be converted
:returns: **str** with the subnet mask representation for this many bits
:raises: **ValueError** if given a number of bits outside the range of 0-128
"""
if bits > 128 or bits < 0:
raise ValueError("A mask can only be 0-128 bits, got %i" % bits)
elif bits == 128:
return FULL_IPv6_MASK
# get the binary representation of the mask
mask_bin = _get_binary(2 ** bits - 1, 128)[::-1]
# breaks it into sixteen character groupings
groupings = [mask_bin[16 * i:16 * (i + 1)] for i in xrange(8)]
# converts each group into its hex value
return ":".join(["%04x" % int(group, 2) for group in groupings]).upper()
def _get_masked_bits(mask):
"""
Provides the number of bits that an IPv4 subnet mask represents. Note that
not all masks can be represented by a bit count.
:param str mask: mask to be converted
:returns: **int** with the number of bits represented by the mask
:raises: **ValueError** if the mask is invalid or can't be converted
"""
if not is_valid_ipv4_address(mask):
raise ValueError("'%s' is an invalid subnet mask" % mask)
# converts octets to binary representation
mask_bin = _get_address_binary(mask)
mask_match = re.match("^(1*)(0*)$", mask_bin)
if mask_match:
return 32 - len(mask_match.groups()[1])
else:
raise ValueError("Unable to convert mask to a bit count: %s" % mask)
def _get_binary(value, bits):
"""
Provides the given value as a binary string, padded with zeros to the given
number of bits.
:param int value: value to be converted
:param int bits: number of bits to pad to
"""
# http://www.daniweb.com/code/snippet216539.html
return "".join([str((value >> y) & 1) for y in range(bits - 1, -1, -1)])
def _get_address_binary(address):
"""
Provides the binary value for an IPv4 or IPv6 address.
:returns: **str** with the binary representation of this address
:raises: **ValueError** if address is neither an IPv4 nor IPv6 address
"""
if is_valid_ipv4_address(address):
return "".join([_get_binary(int(octet), 8) for octet in address.split(".")])
elif is_valid_ipv6_address(address):
address = expand_ipv6_address(address)
return "".join([_get_binary(int(grouping, 16), 16) for grouping in address.split(":")])
else:
raise ValueError("'%s' is neither an IPv4 or IPv6 address" % address)
def _hmac_sha256(key, msg):
"""
Generates a sha256 digest using the given key and message.
:param str key: starting key for the hash
:param str msg: message to be hashed
:returns: sha256 digest of msg as bytes, hashed using the given key
"""
return hmac.new(key, msg, hashlib.sha256).digest()
def _cryptovariables_equal(x, y):
"""
Compares two strings for equality securely.
:param str x: string to be compared.
:param str y: the other string to be compared.
:returns: **True** if both strings are equal, **False** otherwise.
"""
return (
_hmac_sha256(CRYPTOVARIABLE_EQUALITY_COMPARISON_NONCE, x) ==
_hmac_sha256(CRYPTOVARIABLE_EQUALITY_COMPARISON_NONCE, y))
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