619435dd8e
The initial code for this fixed used rstrip incorrectly. This implementation uses endswith and rindex instead and should read a bit more easily. Also added a unit test to test that 'deleted' exe's are filtered correctly. Fixes LP Bug #967931. Change-Id: I1783a8e2d59edd35734673b23e295f5a0b80b988
148 lines
4.9 KiB
Python
Executable File
148 lines
4.9 KiB
Python
Executable File
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright (c) 2011 OpenStack, LLC.
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# All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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import os
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import re
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class CommandFilter(object):
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"""Command filter only checking that the 1st argument matches exec_path"""
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def __init__(self, exec_path, run_as, *args):
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self.exec_path = exec_path
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self.run_as = run_as
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self.args = args
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def match(self, userargs):
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"""Only check that the first argument (command) matches exec_path"""
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if (os.path.basename(self.exec_path) == userargs[0]):
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return True
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return False
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def get_command(self, userargs):
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"""Returns command to execute (with sudo -u if run_as != root)."""
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if (self.run_as != 'root'):
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# Used to run commands at lesser privileges
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return ['sudo', '-u', self.run_as, self.exec_path] + userargs[1:]
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return [self.exec_path] + userargs[1:]
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def get_environment(self, userargs):
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"""Returns specific environment to set, None if none"""
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return None
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class RegExpFilter(CommandFilter):
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"""Command filter doing regexp matching for every argument"""
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def match(self, userargs):
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# Early skip if command or number of args don't match
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if (len(self.args) != len(userargs)):
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# DENY: argument numbers don't match
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return False
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# Compare each arg (anchoring pattern explicitly at end of string)
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for (pattern, arg) in zip(self.args, userargs):
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try:
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if not re.match(pattern + '$', arg):
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break
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except re.error:
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# DENY: Badly-formed filter
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return False
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else:
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# ALLOW: All arguments matched
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return True
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# DENY: Some arguments did not match
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return False
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class DnsmasqFilter(CommandFilter):
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"""Specific filter for the dnsmasq call (which includes env)"""
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def match(self, userargs):
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if (userargs[0].startswith("FLAGFILE=") and
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userargs[1].startswith("NETWORK_ID=") and
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userargs[2] == "dnsmasq"):
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return True
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return False
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def get_command(self, userargs):
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return [self.exec_path] + userargs[3:]
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def get_environment(self, userargs):
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env = os.environ.copy()
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env['FLAGFILE'] = userargs[0].split('=')[-1]
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env['NETWORK_ID'] = userargs[1].split('=')[-1]
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return env
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class KillFilter(CommandFilter):
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"""Specific filter for the kill calls.
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1st argument is a list of accepted signals (emptystring means no signal)
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2nd argument is a list of accepted affected executables.
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This filter relies on /proc to accurately determine affected
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executable, so it will only work on procfs-capable systems (not OSX).
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"""
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def match(self, userargs):
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if userargs[0] != "kill":
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return False
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args = list(userargs)
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if len(args) == 3:
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signal = args.pop(1)
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if signal not in self.args[0]:
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# Requested signal not in accepted list
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return False
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else:
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if len(args) != 2:
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# Incorrect number of arguments
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return False
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if '' not in self.args[0]:
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# No signal, but list doesn't include empty string
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return False
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try:
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command = os.readlink("/proc/%d/exe" % int(args[1]))
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# NOTE(dprince): /proc/PID/exe may have ' (deleted)' on
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# the end if an executable is updated or deleted
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if command.endswith(" (deleted)"):
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command = command[:command.rindex(" ")]
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if command not in self.args[1]:
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# Affected executable not in accepted list
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return False
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except (ValueError, OSError):
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# Incorrect PID
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return False
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return True
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class ReadFileFilter(CommandFilter):
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"""Specific filter for the utils.read_file_as_root call"""
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def __init__(self, file_path, *args):
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self.file_path = file_path
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super(ReadFileFilter, self).__init__("/bin/cat", "root", *args)
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def match(self, userargs):
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if userargs[0] != 'cat':
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return False
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if userargs[1] != self.file_path:
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return False
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if len(userargs) != 2:
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return False
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return True
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