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
|
#!/usr/bin/env python3
import json
import sys
import time
import os
import hashlib
import base64
from http.server import BaseHTTPRequestHandler, HTTPServer
from urllib.parse import urlparse, parse_qs
from typing import Dict
SNAKEOIL_PUBLIC_KEY = os.environ['SNAKEOIL_PUBLIC_KEY']
MOCKUSER="mockuser_nixos_org"
MOCKADMIN="mockadmin_nixos_org"
def w(msg: bytes):
sys.stderr.write(f"{msg}\n")
sys.stderr.flush()
def gen_fingerprint(pubkey: str):
decoded_key = base64.b64decode(pubkey.encode("ascii").split()[1])
return hashlib.sha256(decoded_key).hexdigest()
def gen_email(username: str):
"""username seems to be a 21 characters long number string, so mimic that in a reproducible way"""
return str(int(hashlib.sha256(username.encode()).hexdigest(), 16))[0:21]
def gen_mockuser(username: str, uid: str, gid: str, home_directory: str, snakeoil_pubkey: str) -> Dict:
snakeoil_pubkey_fingerprint = gen_fingerprint(snakeoil_pubkey)
# seems to be a 21 characters long numberstring, so mimic that in a reproducible way
email = gen_email(username)
return {
"loginProfiles": [
{
"name": email,
"posixAccounts": [
{
"primary": True,
"username": username,
"uid": uid,
"gid": gid,
"homeDirectory": home_directory,
"operatingSystemType": "LINUX"
}
],
"sshPublicKeys": {
snakeoil_pubkey_fingerprint: {
"key": snakeoil_pubkey,
"expirationTimeUsec": str((time.time() + 600) * 1000000), # 10 minutes in the future
"fingerprint": snakeoil_pubkey_fingerprint
}
}
}
]
}
class ReqHandler(BaseHTTPRequestHandler):
def _send_json_ok(self, data: dict):
self.send_response(200)
self.send_header('Content-type', 'application/json')
self.end_headers()
out = json.dumps(data).encode()
w(out)
self.wfile.write(out)
def _send_json_success(self, success=True):
self.send_response(200)
self.send_header('Content-type', 'application/json')
self.end_headers()
out = json.dumps({"success": success}).encode()
w(out)
self.wfile.write(out)
def _send_404(self):
self.send_response(404)
self.end_headers()
def do_GET(self):
p = str(self.path)
pu = urlparse(p)
params = parse_qs(pu.query)
# users endpoint
if pu.path == "/computeMetadata/v1/oslogin/users":
# mockuser and mockadmin are allowed to login, both use the same snakeoil public key
if params.get('username') == [MOCKUSER] or params.get('uid') == ["1009719690"]:
username = MOCKUSER
uid = "1009719690"
elif params.get('username') == [MOCKADMIN] or params.get('uid') == ["1009719691"]:
username = MOCKADMIN
uid = "1009719691"
else:
self._send_404()
return
self._send_json_ok(gen_mockuser(username=username, uid=uid, gid=uid, home_directory=f"/home/{username}", snakeoil_pubkey=SNAKEOIL_PUBLIC_KEY))
return
# we need to provide something at the groups endpoint.
# the nss module does segfault if we don't.
elif pu.path == "/computeMetadata/v1/oslogin/groups":
self._send_json_ok({
"posixGroups": [
{"name" : "demo", "gid" : 4294967295}
],
})
return
# authorize endpoint
elif pu.path == "/computeMetadata/v1/oslogin/authorize":
# is user allowed to login?
if params.get("policy") == ["login"]:
# mockuser and mockadmin are allowed to login
if params.get('email') == [gen_email(MOCKUSER)] or params.get('email') == [gen_email(MOCKADMIN)]:
self._send_json_success()
return
self._send_json_success(False)
return
# is user allowed to become root?
elif params.get("policy") == ["adminLogin"]:
# only mockadmin is allowed to become admin
self._send_json_success((params['email'] == [gen_email(MOCKADMIN)]))
return
# send 404 for other policies
else:
self._send_404()
return
else:
sys.stderr.write(f"Unhandled path: {p}\n")
sys.stderr.flush()
self.send_response(404)
self.end_headers()
self.wfile.write(b'')
if __name__ == '__main__':
s = HTTPServer(('0.0.0.0', 80), ReqHandler)
s.serve_forever()
|