1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
|
#!/usr/bin/env python3
# Copyright (c) 2018 Egor Tensin <Egor.Tensin@gmail.com>
# This file is part of the "audit-scripts" project.
# For details, see https://github.com/egor-tensin/audit-scripts.
# Distributed under the MIT License.
import argparse
import contextlib
import grp
import logging
import logging.config
import logging.handlers
import multiprocessing as mp
import os
import pwd
import sys
def console_log_formatter():
fmt = '%(asctime)s | %(processName)s | %(levelname)s | %(message)s'
datefmt = '%Y-%m-%d %H:%M:%S'
return logging.Formatter(fmt=fmt, datefmt=datefmt)
def console_log_level():
return logging.DEBUG
def console_log_handler():
handler = logging.StreamHandler()
handler.setFormatter(console_log_formatter())
handler.setLevel(console_log_level())
return handler
@contextlib.contextmanager
def launch_logging_thread(queue):
process = mp.current_process()
process.name = 'scandir'
listener = logging.handlers.QueueListener(queue, console_log_handler())
listener.start()
try:
yield
finally:
listener.stop()
@contextlib.contextmanager
def setup_logging(queue):
config = {
'version': 1,
'handlers': {
'sink': {
'class': 'logging.handlers.QueueHandler',
'queue': queue,
},
},
'root': {
'handlers': ['sink'],
'level': 'DEBUG',
},
}
logging.config.dictConfig(config)
try:
yield
except Exception as e:
logging.exception(e)
def validate_uid(uid):
try:
return pwd.getpwuid(uid).pw_uid
except KeyError:
return None
def validate_gid(gid):
try:
return grp.getgrgid(gid).gr_gid
except KeyError:
return None
def map_user_name(user_name):
try:
return pwd.getpwnam(user_name).pw_uid
except KeyError:
return None
def map_group_name(group_name):
try:
return grp.getgrnam(group_name).gr_gid
except KeyError:
return None
def parse_user_name(src):
uid = map_user_name(src)
if uid is None:
raise argparse.ArgumentTypeError('unknown user name: {}'.format(src))
return uid
def parse_group_name(src):
gid = map_group_name(src)
if gid is None:
raise argparse.ArgumentTypeError('unknown group name: {}'.format(src))
return gid
def parse_uid(src):
try:
uid = int(src)
except ValueError:
return parse_user_name(src)
uid = validate_uid(uid)
if uid is None:
raise argparse.ArgumentTypeError('unknown UID: {}'.format(src))
return uid
def parse_gid(src):
try:
gid = int(src)
except ValueError:
return parse_group_name(src)
gid = validate_gid(gid)
if gid is None:
raise argparse.ArgumentTypeError('unknown GID: {}'.format(src))
return gid
def get_primary_gid(uid):
return pwd.getpwuid(uid).pw_gid
def parse_args(argv=None):
if argv is None:
argv = sys.argv[1:]
parser = argparse.ArgumentParser()
parser.add_argument('root_dir', default='/', nargs='?', metavar='DIR',
help='set root directory')
parser.add_argument('--user', '-u', dest='uid', required=True,
metavar='USER', type=parse_uid,
help='set new process\' UID')
parser.add_argument('--group', '-g', dest='gid',
metavar='GROUP', type=parse_gid,
help='set new process\' GID')
args = parser.parse_args(argv)
if args.gid is None:
args.gid = get_primary_gid(args.uid)
return args
def dump_process_info():
ruid, euid, suid = os.getresuid()
logging.info('User IDs:')
logging.info('\tReal: %d', ruid)
logging.info('\tEffective: %d', euid)
logging.info('\tSaved: %d', suid)
rgid, egid, sgid = os.getresgid()
logging.info('Group IDs:')
logging.info('\tReal: %d', rgid)
logging.info('\tEffective: %d', egid)
logging.info('\tSaved: %d', sgid)
def check_root():
if os.getuid() == 0:
return True
logging.error('Must be run as root')
return False
def scandir(dir_path):
try:
entry_it = os.scandir(dir_path)
except (PermissionError, FileNotFoundError) as e:
logging.warning('%s', e)
return
with entry_it:
yield from entry_it
def enum_dirs(dir_path):
for entry in scandir(dir_path):
if entry.is_dir(follow_symlinks=False):
yield entry.path
def is_writable_via_access(dir_path):
return os.access(dir_path, os.W_OK | os.X_OK)
def is_writable(dir_path):
return is_writable_via_access(dir_path)
def drop_privileges(uid, gid):
if not check_root():
return
os.setgroups([])
os.setgid(gid)
os.setuid(uid)
os.umask(0o77)
@contextlib.contextmanager
def close_queue(queue):
try:
yield
finally:
queue.put(None)
def access_loop(access_queue, scandir_queue):
for dir_list in iter(access_queue.get, None):
denied_dir_list = []
for dir_path in dir_list:
if is_writable(dir_path):
logging.info('Writable: %s', dir_path)
else:
denied_dir_list.append(dir_path)
if not denied_dir_list:
break
scandir_queue.put(denied_dir_list)
def access_main(args, log_queue, access_queue, scandir_queue):
with close_queue(scandir_queue), setup_logging(log_queue):
drop_privileges(args.uid, args.gid)
dump_process_info()
access_loop(access_queue, scandir_queue)
def scandir_loop(access_queue, scandir_queue):
for parent_dir_list in iter(scandir_queue.get, None):
child_dir_list = [child_dir
for parent_dir in parent_dir_list
for child_dir in enum_dirs(parent_dir)]
if not child_dir_list:
break
access_queue.put(child_dir_list)
def scandir_main(access_queue, scandir_queue):
with close_queue(access_queue):
if not check_root():
return
dump_process_info()
scandir_loop(access_queue, scandir_queue)
def main(argv=None):
log_queue = mp.Queue()
with launch_logging_thread(log_queue), setup_logging(log_queue):
prog_args = parse_args(argv)
access_queue = mp.SimpleQueue()
scandir_queue = mp.SimpleQueue()
access_process_args = prog_args, log_queue, access_queue, scandir_queue
access_process = mp.Process(target=access_main,
args=access_process_args,
name='access')
access_queue.put([prog_args.root_dir])
access_process.start()
scandir_main(access_queue, scandir_queue)
access_process.join()
if __name__ == '__main__':
mp.set_start_method('spawn')
main()
|