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
|
# Copyright 2019 VyOS maintainers and contributors <maintainers@vyos.io>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library. If not, see <http://www.gnu.org/licenses/>.
import sys
import os
import re
import fileinput
import subprocess
def check_and_add_host_key(host_name):
"""
Filter host keys and prompt for adding key to known_hosts file, if
needed.
"""
known_hosts = '{}/.ssh/known_hosts'.format(os.getenv('HOME'))
if not os.path.exists(known_hosts):
mode = 0o600
os.mknod(known_hosts, 0o600)
keyscan_cmd = 'ssh-keyscan -t rsa {} 2>/dev/null'.format(host_name)
try:
host_key = subprocess.check_output(keyscan_cmd, shell=True,
stderr=subprocess.DEVNULL,
universal_newlines=True)
except subprocess.CalledProcessError as err:
sys.exit("Can not get RSA host key")
# libssh2 (jessie; stretch) does not recognize ec host keys, and curl
# will fail with error 51 if present in known_hosts file; limit to rsa.
usable_keys = False
offending_keys = []
for line in fileinput.input(known_hosts, inplace=True):
if host_name in line and 'ssh-rsa' in line:
if line.split()[-1] != host_key.split()[-1]:
offending_keys.append(line)
continue
else:
usable_keys = True
if host_name in line and not 'ssh-rsa' in line:
continue
sys.stdout.write(line)
if usable_keys:
return
if offending_keys:
print("Host key has changed!")
print("If you trust the host key fingerprint below, continue.")
fingerprint_cmd = 'ssh-keygen -lf /dev/stdin <<< "{}"'.format(host_key)
try:
fingerprint = subprocess.check_output(fingerprint_cmd, shell=True,
stderr=subprocess.DEVNULL,
universal_newlines=True)
except subprocess.CalledProcessError as err:
sys.exit("Can not get RSA host key fingerprint.")
print("RSA host key fingerprint is {}".format(fingerprint.split()[1]))
response = input("Do you trust this host? [y]/n ")
if not response or response == 'y':
with open(known_hosts, 'a+') as f:
print("Adding {} to the list of known"
" hosts.".format(host_name))
f.write(host_key)
else:
sys.exit("Host not trusted")
def get_remote_config(remote_file):
""" Invoke curl to download remote (config) file.
Args:
remote file URI:
scp://<user>[:<passwd>]@<host>/<file>
sftp://<user>[:<passwd>]@<host>/<file>
http://<host>/<file>
https://<host>/<file>
ftp://<user>[:<passwd>]@<host>/<file>
tftp://<host>/<file>
"""
request = dict.fromkeys(['protocol', 'host', 'file', 'user', 'passwd'])
protocols = ['scp', 'sftp', 'http', 'https', 'ftp', 'tftp']
or_protocols = '|'.join(protocols)
request_match = re.match(r'(' + or_protocols + r')://(.*?)(/.*)',
remote_file)
if request_match:
(request['protocol'], request['host'],
request['file']) = request_match.groups()
else:
print("Malformed URI")
sys.exit(1)
user_match = re.search(r'(.*)@(.*)', request['host'])
if user_match:
request['user'] = user_match.groups()[0]
request['host'] = user_match.groups()[1]
passwd_match = re.search(r'(.*):(.*)', request['user'])
if passwd_match:
# Deprectated in RFC 3986, but maintain for backward compatability.
request['user'] = passwd_match.groups()[0]
request['passwd'] = passwd_match.groups()[1]
remote_file = '{0}://{1}{2}'.format(request['protocol'], request['host'], request['file'])
if request['protocol'] in ('scp', 'sftp'):
check_and_add_host_key(request['host'])
redirect_opt = ''
if request['protocol'] in ('http', 'https'):
redirect_opt = '-L'
# Try header first, and look for 'OK' or 'Moved' codes:
curl_cmd = 'curl {0} -q -I {1}'.format(redirect_opt, remote_file)
try:
curl_output = subprocess.check_output(curl_cmd, shell=True,
universal_newlines=True)
except subprocess.CalledProcessError:
sys.exit(1)
return_vals = re.findall(r'^HTTP\/\d+\.?\d\s+(\d+)\s+(.*)$',
curl_output, re.MULTILINE)
for val in return_vals:
if int(val[0]) not in [200, 301, 302]:
print('HTTP error: {0} {1}'.format(*val))
sys.exit(1)
if request['user'] and not request['passwd']:
curl_cmd = 'curl -# -u {0} {1}'.format(request['user'], remote_file)
else:
curl_cmd = 'curl {0} -# {1}'.format(redirect_opt, remote_file)
try:
config_file = subprocess.check_output(curl_cmd, shell=True,
universal_newlines=True)
except subprocess.CalledProcessError:
config_file = None
return config_file
|
