e528aacbbe
The match() method in the KillFilter is a bit buggy. Since most/many run through this logic in their way to being matched, it creates subtle issues elsewhere, specifically during linux_net bridge creation. This fixes two issues. 1. userargs gets elements directly popped off of it. If the KillFilter does not match the command its checking, the later filter that does is missing one argument. 2. Type error on pid when checking /proc, this was causing issues on instance tear down / kill -HUP'ing dnsmasq. Fixes bug 921784 Change-Id: I058ff2276e3154e8c1f6cc7077fa485db60e5827
126 lines
4.1 KiB
Python
Executable File
126 lines
4.1 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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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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pid = int(args[1])
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try:
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command = os.readlink("/proc/%d/exe" % pid)
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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:
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# Incorrect PID
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return False
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return True
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