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
|
#!/usr/bin/python
import os
import os.path
import cloudinit.util as util
class AuthKeyEntry():
# lines are options, keytype, base64-encoded key, comment
# man page says the following which I did not understand:
# The options field is optional; its presence is determined by whether
# the line starts with a number or not (the options field never starts
# with a number)
options = None
keytype = None
base64 = None
comment = None
is_comment = False
line_in = ""
def __init__(self, line, def_opt=None):
line=line.rstrip("\n\r")
self.line_in = line
if line.startswith("#") or line.strip() == "":
self.is_comment = True
else:
ent = line.strip()
toks = ent.split(None,3)
if len(toks) == 1:
self.base64 = toks[0]
elif len(toks) == 2:
(self.base64, self.comment) = toks
elif len(toks) == 3:
(self.keytype, self.base64, self.comment) = toks
elif len(toks) == 4:
i = 0
ent = line.strip()
quoted = False
# taken from auth_rsa_key_allowed in auth-rsa.c
try:
while (i < len(ent) and
((quoted) or (ent[i] not in (" ", "\t")))):
curc = ent[i]
nextc = ent[i + 1]
if curc == "\\" and nextc == '"':
i = i + 1
elif curc == '"':
quoted = not quoted
i = i + 1
except IndexError as e:
self.is_comment = True
return()
try:
self.options = ent[0:i]
(self.keytype, self.base64, self.comment) = \
ent[i+1:].split(None,3)
except ValueError as e:
# we did not understand this line
self.is_comment = True
if self.options == None and def_opt:
self.options = def_opt
return
def debug(self):
print("line_in=%s\ncomment: %s\noptions=%s\nkeytype=%s\nbase64=%s\ncomment=%s\n" %
(self.line_in, self.is_comment, self.options, self.keytype, self.base64, self.comment)),
def __repr__(self):
if self.is_comment:
return(self.line_in)
else:
toks = [ ]
for e in (self.options, self.keytype, self.base64, self.comment):
if e:
toks.append(e)
return(' '.join(toks))
def update_authorized_keys(fname, keys):
# keys is a list of AuthKeyEntries
# key_prefix is the prefix (options) to prepend
try:
fp = open(fname, "r")
lines = fp.readlines() # lines have carriage return
fp.close()
except IOError as e:
lines = [ ]
ka_stats = { } # keys_added status
for k in keys:
ka_stats[k] = False
to_add = []
for key in keys:
to_add.append(key)
for i in range(0,len(lines)):
ent = AuthKeyEntry(lines[i])
for k in keys:
if k.base64 == ent.base64 and not k.is_comment:
ent = k
try:
to_add.remove(k)
except ValueError:
pass
lines[i] = str(ent)
# now append any entries we did not match above
for key in to_add:
lines.append(str(key))
if len(lines) == 0:
return("")
else:
return('\n'.join(lines) + "\n")
def setup_user_keys(keys, user, key_prefix, log=None):
import pwd
saved_umask = os.umask(077)
pwent = pwd.getpwnam(user)
ssh_dir = '%s/.ssh' % pwent.pw_dir
if not os.path.exists(ssh_dir):
os.mkdir(ssh_dir)
os.chown(ssh_dir, pwent.pw_uid, pwent.pw_gid)
try:
ssh_cfg = parse_ssh_config()
akeys = ssh_cfg.get("AuthorizedKeysFile","%h/.ssh/authorized_keys")
akeys = akeys.replace("%h", pwent.pw_dir)
akeys = akeys.replace("%u", user)
authorized_keys = akeys
except Exception as e:
authorized_keys = '%s/.ssh/authorized_keys' % pwent.pw_dir
if log:
util.logexc(log)
key_entries = []
for k in keys:
ke = AuthKeyEntry(k, def_opt=key_prefix)
key_entries.append(ke)
content = update_authorized_keys(authorized_keys, key_entries)
util.write_file(authorized_keys, content, 0600)
os.chown(authorized_keys, pwent.pw_uid, pwent.pw_gid)
os.umask(saved_umask)
if __name__ == "__main__":
import sys
# usage: orig_file, new_keys, [key_prefix]
# prints out merged, where 'new_keys' will trump old
## example
## ### begin authorized_keys ###
# ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEA28CDAGtxSucHezSKqwh1wAs39xdeZTSVmmyMcKDI5Njnd1d/Uhgj/awxP0Whep8eRSm6F+Xgwi0pH1KNPCszPvq+03K+yi3YkYkQIkVBhctK6AP/UmlVQTVmjJdEvgtrppFTjCzf16q0BT0mXX5YFV3csgm8cJn7UveKHkYjJp8= smoser-work
# ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA3I7VUf2l5gSn5uavROsc5HRDpZdQueUq5ozemNSj8T7enqKHOEaFoU2VoPgGEWC9RyzSQVeyD6s7APMcE82EtmW4skVEgEGSbDc1pvxzxtchBj78hJP6Cf5TCMFSXw+Fz5rF1dR23QDbN1mkHs7adr8GW4kSWqU7Q7NDwfIrJJtO7Hi42GyXtvEONHbiRPOe8stqUly7MvUoN+5kfjBM8Qqpfl2+FNhTYWpMfYdPUnE7u536WqzFmsaqJctz3gBxH9Ex7dFtrxR4qiqEr9Qtlu3xGn7Bw07/+i1D+ey3ONkZLN+LQ714cgj8fRS4Hj29SCmXp5Kt5/82cD/VN3NtHw== smoser@brickies
# ### end authorized_keys ###
#
# ### begin new_keys ###
# ssh-rsa nonmatch smoser@newhost
# ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAIEA28CDAGtxSucHezSKqwh1wAs39xdeZTSVmmyMcKDI5Njnd1d/Uhgj/awxP0Whep8eRSm6F+Xgwi0pH1KNPCszPvq+03K+yi3YkYkQIkVBhctK6AP/UmlVQTVmjJdEvgtrppFTjCzf16q0BT0mXX5YFV3csgm8cJn7UveKHkYjJp8= new_comment
# ### end new_keys ###
#
# Then run as:
# program authorized_keys new_keys 'no-port-forwarding,command=\"echo hi world;\"'
def_prefix = None
orig_key_file = sys.argv[1]
new_key_file = sys.argv[2]
if len(sys.argv) > 3:
def_prefix = sys.argv[3]
fp = open(new_key_file)
newkeys = [ ]
for line in fp.readlines():
newkeys.append(AuthKeyEntry(line, def_prefix))
fp.close()
print update_authorized_keys(orig_key_file, newkeys)
def parse_ssh_config(fname="/etc/ssh/sshd_config"):
ret = { }
fp=open(fname)
for l in fp.readlines():
l = l.strip()
if not l or l.startswith("#"):
continue
key,val = l.split(None,1)
ret[key]=val
fp.close()
return(ret)
|
