-
Notifications
You must be signed in to change notification settings - Fork 1
/
do_auth.py
547 lines (493 loc) · 21.5 KB
/
do_auth.py
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
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
#!/usr/bin/python
# Program I threw together to do the things tac_plus won't
# It allows very granular control. Please visit tacacs.org as
# this is continually updated
# History:
# Version 1.1
# Simple typo - a stray 's' botched a deny statement
# Version 1.2
# Did you know a firewall doesn't end it's commands with a <cr>?
# Version 1.3
# Needs a default user. If most of your users have the same access,
# and you have a default access in tac_plus.conf, you need it here as
# well.
# Version 1.4
# CRS doesn't send $address when in conf t
# Added -fix_crs_bug as as simple/stupid workaround
# Version 1.5
# Mistake in the example, thanks to aojea
# Version 1.6
# Added support for other services besides service=shell
# (ie - they work, by they match on IP/Source only. If you have examples of
# pairs other than cmd to match on, please bring them to my attention)
# Version 1.7
# Fixed reression
# Support for replacing av pairs
# Version 1.8
# Nexus support (tac_pair format different)
# Version 1.9
# Better Nexus Support
# Only send roles to Nexus
# Better av pair replacement
# TO DO (If anybody bothers to request them)
# Possible web front end - simple cgi shouldn't be too hard to write
# More work on tac_pairs - sniff wlc traffic
# Write a better option parser to ignore options not sent (See CRS Bug)
'''
do_auth.py [-options]
Version 1.9
do_auth is a python program I wrote to work as an authorization script for
tacacs to allow greater flexability in tacacs authentication. It allows
a user to be part of many predefined groups that can allow different
access to different devices based on ip, user, and source address.
Do not play with do_auth untill you have a firm grasp on tac_plus!
-u Username. Mandatory. $user
-i Ip address of user. Optional. If not specified, all host_ entries
are ignored and can be omitted. $address
**Note: If you use IOS-XR, you MUST add -fix_crs_bug after $address
due to a bug in IOS-XR
-d Device address. Optional. If not specified, all device_ entries
are ignored and can be omitted. $name
-f Config Filename. Default is do_auth.ini.
-l Logfile. Default is log.txt.
-D Debug mode. Allows you to call the program without reading
from stdin. Useful to test your configuration before going
live. Sets a default command of "show users wides".
Groups are assigned to users in the [users] section. A user must
be assigned to one or more groups, one per line. Groups are defined
in brackets, but can be any name. Each group can have up to 6 options
as defined below.
host_deny Deny any user coming from this host. Optional.
host_allow Allow users from this range. Mandatory if
-i is specified.
device_deny Deny any device with this IP. Optional.
device_permit Allow this range. Mandatory if -d is specified
command_deny Deny these commands. Optional.
command_permit Allow these commands. Mandatory.
av_pairs list of av pairs to replace if found. Optional - be careful
The options are parsed in order till a match is found. Obviously,
for login, the commands section is not parsed. If a match is not
found, or a deny is found, we move on to the next group. At the
end, we have an implicit deny if no groups match.
An simple example is as follows.
[users]
homer =
simpson_group
television_group
stimpy =
television_group
[simpson_group]
host_deny =
1.1.1.1
1.1.1.2
host_allow =
1.1.1.*
device_permit =
10.1.1.*
command_permit =
.*
[television_group]
host_allow =
.*
device_permit =
.*
command_permit =
show.*
Example tacacs line: after authorization "/usr/bin/python
/root/do_auth.pyc -i $address -fix_crs_bug -u $user -d $name -l /root/log.txt
-f /root/do_auth.ini"
(that's one line)
Example av_pair:
The following example will replace any priv-lvl with priv-lvl=1 ONLY if passed.
Think of "av_pairs" as a find/replace function.
av_pairs =
priv-lvl=1
Brocade has a brocade-privlvl which I like. It maps priv-lvl to
brocade-privlvl, but priv-lvl=1 results in interface privileges. Here
is an example of how to map to brocade-privlvl=5 which has no modification
rights. Unfortunately, it does require you to put in the IP's of your gear.
The following group would go before other groups:
[brocade_readonly]
host_allow =
.*
device_permit =
192.168.1.*
command_permit =
.*
av_pairs =
priv-lvl,brocade-privlvl=5
You could also put "priv-lvl=15,brocade-privlvl=5" or whatever your
tac_plus deamon is passing; as long as it's a match it accomplished the same
thing. In this example, we essentially replace the whole av_pair resulting
in the user having only read access. Alternatively, a good "disable account"
can be created by simpley doing:
av_pairs =
brocade-privlvl=5
This results in the brocades having read/only, and the Cisco's go into disable
because they don't understand it. (We're assuming that the user has no enable
account or the priv-lvl is pointless) You could also add a shell role for nexus,
which we will discuss next. (shell:roles="network-admin")
NEXUS - Due to a slight change in the nexus, do_auth is able to
discern if a device is a nexus or not. In tac_plus, do the following:
service = exec {
priv-lvl = 1
shell:roles=\"\\"network-operator\\""
idletime = 3
timeout = 15
}
after authorization <do_auth yada yada>
This configuration does NOT work without do_auth. However, WITH do_auth,
do_auth will only send shell:roles to Nexus switches, allowing your
other gear to work correctly. Simply put av_pairs in your do_auth, and
it will figure it out for you. (If not, it won't touch them. The logic is
simple: If (av_pairs in .ini): Then (do_stuff), Else (exit(2)- Don't modify 'em!))
Roles can also be modified in a do_auth group, as below:
av_pairs =
priv-lvl=15
shell:roles="network-admin"
Also of note, you MUST USE DOUBLE QUOTES to get tac_plus to correctly
pass "network-operator" in the service example above. UNLESS you are
modifying the key with do_auth in av_pairs - it will fix the quotes.
BUGS: You must know your regular expressions. If you enter a bad
expression, such as *. instead of .*, python re will freak out and
not evaluate the expression. (Thought about netaddr, but would you
really install it?)
CAVEATS: One group can not take away what another group grants via deny.
If a match is not found, it will go on to the next group. If a deny is
matched, it will go on to the next group.
Order is crucial - the groups should go from more specific to less
specific. In the above example, if television_group was put before
simpson_group, simpson_group would never be called because
televsion_group catches everything in device_permit.
HELP: If somebody has a WLC or other unknown network equipment, I
require some testing/sniffing done - thanks!!
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License version 3 or any
later version as published by the Free Software Foundation,
http://www.gnu.org/
This program 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
General Public License for more details.
Written by Dan Schmidt - Please visit tacacs.org to check for updates.
'''
import sys,re,getopt,ConfigParser
from time import strftime
# I really don't want to deal with these exceptions more than once
# filename is only used in log statements
def get_attribute(config, the_section, the_option, log_file, filename):
if not config.has_section(the_section):
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "Error: Section '%s' does not exist in %s\n"
% (the_section, filename))
sys.exit(1)
if not config.has_option(the_section, the_option):
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "Error: Option '%s' does not exist in section %s in file %s\n"
% (the_option, the_section, filename))
sys.exit(1)
#Should not have any exceptions - BUT, just in case
try:
attributes = config.get(the_section, the_option)
except ConfigParser.NoSectionError:
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "Error: Section '%s' Doesn't Exist!\n"
% (the_section))
sys.exit(1)
except ConfigParser.DuplicateSectionError:
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "Error: Duplicate section '%s'\n"
% (the_section))
sys.exit(1)
except ConfigParser.NoOptionError:
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "Error: '%s' not found in section '%s\n'"
% (the_option, the_section))
sys.exit(1)
#To do: finish exceptions.
except ConfigParser.ParsingError:
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "Error: Can't parse file '%s'! (You got me)\n"
% (filename))
sys.exit(1)
attributes = attributes.split('\n')
#Strip empty lines
attributes2 = []
for line in attributes:
if line:
attributes2.append(line)
return attributes2
# Can't make it part of get_attribute... oh well...
# We need someway to check to see if a username exists with out exit(1)
def check_username(config, log_file, user_name):
if not config.has_section('users'):
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "Error: users section doesn't exist!")
sys.exit(1)
if config.has_option('users', user_name):
return True
else:
return False
# If match item in our_list, true, else false
# Example - if deny section has a match for 10.1.1.1,
# return True, else False
# If the section doesn't exist, we assume an
# impicity deny/false
def match_it(the_section, the_option, match_item, config, log_file, filename):
if config.has_option(the_section,the_option):
our_list = get_attribute(config, the_section, the_option, log_file, filename)
for item in our_list:
#p = re.compile(item) Not necessary - we're only using it once
if re.match(item,match_item):
return True
return False
def main():
#Defaults
filename = "do_auth.ini"
log_name = "log.txt"
user_name = ""
ip_addr = ""
device = ""
is_debug = False
argv = sys.argv
try:
optlist, args = getopt.getopt(sys.argv[1:], 'i:u:f:l:d:?:D', ['fix_crs_bug','?', '-?', 'help', 'Help'])
except getopt.GetoptError, err:
print str(err)
print __doc__
sys.exit(1)
for (i, j) in optlist:
if i == '-i':
ip_addr = j
elif i == '-u':
user_name = j
elif i == '-f':
filename = j
elif i == '-l':
log_name = j
elif i == '-d':
device = j
elif i in ('?', '-?', 'help', 'Help'):
print __doc__
sys.exit(1)
elif i == '-D':
is_debug = True
else:
print 'Unknown option:', i
sys.exit(1)
if len(argv) < 7:
print __doc__
sys.exit(1)
log_file = open (log_name, "a")
#DEBUG! We at least got CALLED
# log_file.write('Hello World!' + '\n')
#read AV pairs
av_pairs = []
if not (is_debug):
for line in sys.stdin:
av_pairs.append(line)
else:
#Default Debug command is "show users wide"
#Later versions will allow this to be set
av_pairs.append("service=shell\n")
av_pairs.append("cmd=show\n")
av_pairs.append("cmd-arg=users\n")
av_pairs.append("cmd-arg=wide\n")
av_pairs.append("cmd-arg=<cr>\n")
#DEBUG - print tac pairs
# for item in av_pairs:
# log_file.write(item)
# Function to make cmd's readable
# Not very good, but will do for now
# I don't use any other service other than shell to test!
the_command = ""
return_pairs = ""
if (av_pairs[0] == "service=shell\n"):
if av_pairs[1] == ("cmd=\n"): # #&*@ Nexus!
if len(av_pairs) > 2:
#DEBUG
# log_file.write('Nexus pairs found\n')
return_pairs = av_pairs[2:] #strip the "cmd=" for consistency
#Commands - Concatenate to a readable command
elif av_pairs[1].startswith("cmd="):
our_command = av_pairs[1].split("=")
the_command = our_command[1].strip('\n')
if len(av_pairs) > 2:
i = 2
our_command = av_pairs[i].split("=")
while not (our_command[1] == "<cr>\n"):
the_command = the_command + " " + our_command[1].strip('\n')
i = i + 1
if i == len(av_pairs): # Firewalls don't give a <cr>!!
break
our_command = av_pairs[i].split("=")
#DEBUG - We got the command
#log_file.write(the_command + '\n')
#Login - Get av_pairs to pass back to tac_plus
elif av_pairs[1].startswith("cmd*"): #Anybody know why it's "cmd*"?
if len(av_pairs) > 2:
return_pairs = av_pairs[2:] #You MUST strip the "cmd*" av-pair
# Definately not a Nexus, so strip any nexus pair
for item in return_pairs:
if item.startswith("shell:roles"):
return_pairs.remove(item)
else:
return_pairs = av_pairs
if not user_name:
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "Error: No username entered!\n")
sys.exit(1)
config = ConfigParser.SafeConfigParser()
if not (filename in config.read(filename)):
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "Error: Can't open/parse '%s'\n"
% (filename))
sys.exit(1)
the_section = "users"
# If the user doesn't exist, just use the default settings
# Kind of a hack, but it works because we only get_attribute on user_name once.
# We have the : in there which we can use to split if required
if not check_username(config, log_file, user_name):
user_name = (user_name + ":(default)")
groups = get_attribute(config, "users", "default", log_file, filename)
else:
groups = get_attribute(config, "users", user_name, log_file, filename)
for this_group in groups:
if ip_addr:
if match_it(this_group, "host_deny", ip_addr, config, log_file, filename):
if this_group == groups[-1]:
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "User '%s' denied from source '%s' in '%s'->'%s'\n"
% (user_name, ip_addr, this_group, "host_deny"))
sys.exit(1)
else:
# HUM... afterthought. We need it to continue if more groups exist
continue
if not match_it(this_group, "host_allow", ip_addr, config, log_file, filename):
#Stupid IOS-XR
if ip_addr == "-fix_crs_bug":
pass
elif this_group == groups[-1]:
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "User '%s' not allowed from source '%s' in '%s'->'%s'\n"
% (user_name, ip_addr, this_group, "host_allow"))
sys.exit(1)
else:
continue
if device:
if match_it(this_group, "device_deny", device, config, log_file, filename):
if this_group == groups[-1]:
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "User '%s' denied access to device '%s' in '%s'->'%s'\n"
% (user_name, device, this_group, "device_deny"))
sys.exit(1)
else:
continue
if not match_it(this_group, "device_permit", device, config, log_file, filename):
if this_group == groups[-1]:
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "User '%s' not allowed access to device '%s' in '%s'->'%s'\n"
% (user_name, device, this_group, "device_permit"))
sys.exit(1)
else:
continue
# Attempt to modify return pairs
want_tac_pairs = False
if config.has_option(this_group, "av_pairs"):
temp_av_pairs = get_attribute(config, this_group, "av_pairs", log_file, filename)
i = 0
for item in return_pairs:
splt = item.split('=')
if len(splt) > 1:
#DEBUG
#for thing in splt:
# log_file.write('Thing:' + thing + '\n')
for item2 in temp_av_pairs:
item2 = item2.strip()
if item2.find(',') > -1:
splt2 = item2.split(',')
if len(splt2) > 1:
#splt3 = splt2[0].split('=')
if splt[0].find(splt2[0]) > -1:
want_tac_pairs = True
return_pairs[i] = ('%s' % splt2[1])
else:
splt2 = item2.split('=')
if len(splt2) > 1:
if splt[0] == splt2[0].strip(): # strip needed?
want_tac_pairs = True
#DEBUG
#log_file.write("Replacing pairs %s=%s\n" %
# (splt2[0].strip(),
# splt2[1].strip()))
return_pairs[i] = ('%s=%s' % (splt2[0].strip(),
splt2[1].strip()))
i = i + 1
# The previous 4 statements are to deny, it we passed them, proceed
# If we are logging in, return pairs, if not, go no to check the command
# Yes, simply printing them is how you return them
# First, let's make sure we're doing service = shell. If not, just
# allow it. I currently have little knowledge of cmd's sent by other
# services which is why this code is a little klugy.
if return_pairs:
splt = av_pairs[0].split('=') # Removed service in return_pairs
if len(splt) > 1:
if not splt[1].strip() == 'shell':
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "User '%s' granted non-shell access to device '%s' in group '%s' from '%s'\n"
% (user_name, device, this_group, ip_addr))
return_pairs = av_pairs[2:] # Cut the first two?
for item in return_pairs:
#DEBUG
# log_file.write("Returning:%s\n" % item.strip())
print item.strip('\n')
if want_tac_pairs:
#DEBUG
# log_file.write("Exiting status 2\n")
sys.exit(2)
else:
#DEBUG
# log_file.write("Exiting status 0\n")
sys.exit(0) # Don't even TRY to mess with the tac pairs
#Proceed with shell stuff
if not len(the_command) > 0:
#DEBUG
# log_file.write("not len(the_command) > 0\n")
for item in return_pairs:
#DEBUG
# log_file.write("Returning:%s\n" % item.strip())
print item.strip('\n')
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "User '%s' granted access to device '%s' in group '%s' from '%s'\n"
% (user_name, device, this_group, ip_addr))
sys.exit(2)
else: # Check command
if match_it(this_group, "command_deny", the_command, config, log_file, filename):
if this_group == groups[-1]:
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "User '%s' denied command '%s' to device '%s' in '%s'->'%s'\n"
% (user_name, the_command, device, this_group, "command_deny"))
sys.exit(1)
else:
continue
elif match_it(this_group, "command_permit", the_command, config, log_file, filename):
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "User '%s' allowed command '%s' to device '%s' in '%s'->'%s'\n"
% (user_name, the_command, device, this_group, "command_permit"))
sys.exit(0)
else: #exit & log if last group
if this_group == groups[-1]:
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "User '%s' not allowed command '%s' to device '%s' in any group\n"
% (user_name, the_command, device))
#Can't... remember why I added this given the implicit deny
sys.exit(1)
else:
continue
#implicit deny at the end
log_file.write(strftime("%Y-%m-%d %H:%M:%S: ")
+ "User '%s' not allowed access to device '%s' from '%s' in any group\n"
% (user_name, device, ip_addr))
sys.exit(1)
if __name__ == "__main__":
main()