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a2916c06 MW |
1 | #! /usr/bin/python |
2 | ### | |
3 | ### Password management | |
4 | ### | |
5 | ### (c) 2012 Mark Wooding | |
6 | ### | |
7 | ||
8 | ###----- Licensing notice --------------------------------------------------- | |
9 | ### | |
10 | ### This file is part of Chopwood: a password-changing service. | |
11 | ### | |
12 | ### Chopwood is free software; you can redistribute it and/or modify | |
13 | ### it under the terms of the GNU Affero General Public License as | |
14 | ### published by the Free Software Foundation; either version 3 of the | |
15 | ### License, or (at your option) any later version. | |
16 | ### | |
17 | ### Chopwood is distributed in the hope that it will be useful, | |
18 | ### but WITHOUT ANY WARRANTY; without even the implied warranty of | |
19 | ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
20 | ### GNU Affero General Public License for more details. | |
21 | ### | |
22 | ### You should have received a copy of the GNU Affero General Public | |
23 | ### License along with Chopwood; if not, see | |
24 | ### <http://www.gnu.org/licenses/>. | |
25 | ||
26 | from __future__ import with_statement | |
27 | ||
28 | import contextlib as CTX | |
29 | import optparse as OP | |
30 | import os as OS; ENV = OS.environ | |
31 | import shlex as SL | |
32 | import sys as SYS | |
33 | ||
34 | from auto import HOME, VERSION | |
35 | import cgi as CGI | |
36 | import cmdutil as CU | |
37 | import config as CONF; CFG = CONF.CFG | |
38 | import dbmaint as D | |
39 | import httpauth as HA | |
40 | import output as O; OUT = O.OUT | |
41 | import subcommand as SC | |
42 | import util as U | |
43 | ||
44 | for i in ['admin', 'cgi', 'remote', 'user']: | |
45 | __import__('cmd-' + i) | |
46 | ||
47 | ###-------------------------------------------------------------------------- | |
48 | ### Parsing command-line options. | |
49 | ||
50 | ## Command-line options parser. | |
51 | OPTPARSE = SC.SubcommandOptionParser( | |
52 | usage = '%prog SUBCOMMAND [ARGS ...]', | |
53 | version = '%%prog, verion %s' % VERSION, | |
54 | contexts = ['admin', 'userv', 'remote', 'cgi', 'cgi-query', 'cgi-noauth'], | |
55 | commands = SC.COMMANDS, | |
56 | description = """\ | |
57 | Manage all of those annoying passwords. | |
58 | ||
59 | This is free software, and you can redistribute it and/or modify it | |
60 | under the terms of the GNU Affero General Public License | |
61 | <http://www.gnu.org/licenses/agpl-3.0.html>. For a `.tar.gz' file | |
62 | of the source code, use the `source' command. | |
63 | """) | |
64 | ||
65 | OPTS = None | |
66 | ||
67 | ## Set up the global options. | |
68 | for short, long, props in [ | |
69 | ('-c', '--context', { | |
70 | 'metavar': 'CONTEXT', 'dest': 'context', 'default': None, | |
71 | 'help': 'run commands with the given CONTEXT' }), | |
72 | ('-f', '--config-file', { | |
73 | 'metavar': 'FILE', 'dest': 'config', | |
74 | 'default': OS.path.join(HOME, 'chpwd.conf'), | |
75 | 'help': 'read configuration from FILE.' }), | |
bb623e8f MW |
76 | ('-s', '--ssl', { |
77 | 'dest': 'sslp', 'action': 'store_true', | |
78 | 'help': 'pretend CGI connection is carried over SSL/TLS' }), | |
a2916c06 MW |
79 | ('-u', '--user', { |
80 | 'metavar': 'USER', 'dest': 'user', 'default': None, | |
81 | 'help': "impersonate USER, and default context to `userv'." })]: | |
82 | OPTPARSE.add_option(short, long, **props) | |
83 | ||
84 | ###-------------------------------------------------------------------------- | |
85 | ### CGI dispatch. | |
86 | ||
87 | ## The special variables, to be picked out by `cgiparse'. | |
88 | CGI.SPECIAL['%act'] = None | |
89 | CGI.SPECIAL['%nonce'] = None | |
ba8f1b92 | 90 | CGI.SPECIAL['%user'] = None |
a2916c06 MW |
91 | |
92 | ## We don't want to parse arguments until we've settled on a context; but | |
93 | ## issuing redirects in the early setup phase fails because we don't know | |
94 | ## the script name. So package the setup here. | |
95 | def cgi_setup(ctx = 'cgi-noauth'): | |
96 | global OPTS | |
97 | if OPTS: return | |
98 | OPTPARSE.context = ctx | |
99 | OPTS, args = OPTPARSE.parse_args() | |
100 | if args: raise U.ExpectedError, (500, 'Unexpected arguments to CGI') | |
101 | CONF.loadconfig(OPTS.config) | |
102 | D.opendb() | |
103 | ||
104 | def dispatch_cgi(): | |
105 | """Examine the CGI request and invoke the appropriate command.""" | |
106 | ||
107 | ## Start by picking apart the request. | |
108 | CGI.cgiparse() | |
109 | ||
110 | ## We'll be taking items off the trailing path. | |
111 | i, np = 0, len(CGI.PATH) | |
112 | ||
113 | ## Sometimes, we want to run several actions out of the same form, so the | |
114 | ## subcommand name needs to be in the query string. We use the special | |
115 | ## variable `%act' for this. If it's not set, then we use the first elment | |
116 | ## of the path. | |
117 | act = CGI.SPECIAL['%act'] | |
118 | if act is None: | |
119 | if i >= np: | |
120 | cgi_setup() | |
121 | CGI.redirect(CGI.action('login')) | |
122 | return | |
123 | act = CGI.PATH[i] | |
124 | i += 1 | |
125 | ||
126 | ## Figure out which context we're meant to be operating in, according to | |
127 | ## the requested action. Unknown actions result in an error here; known | |
128 | ## actions where we don't have enough authorization send the user back to | |
129 | ## the login page. | |
130 | for ctx in ['cgi-noauth', 'cgi-query', 'cgi']: | |
131 | try: | |
132 | c = OPTPARSE.lookup_subcommand(act, exactp = True, context = ctx) | |
133 | except U.ExpectedError, e: | |
134 | if e.code != 404: raise | |
135 | else: | |
136 | break | |
137 | else: | |
138 | raise e | |
139 | ||
140 | ## Parse the command line, and load configuration. | |
141 | cgi_setup(ctx) | |
142 | ||
143 | ## Check whether we have enough authorization. There's always enough for | |
144 | ## `cgi-noauth'. | |
145 | if ctx != 'cgi-noauth': | |
146 | ||
ba8f1b92 MW |
147 | ## The next part of the URL should be the user name, so that caches don't |
148 | ## cross things over. | |
149 | expuser = CGI.SPECIAL['%user'] | |
150 | if expuser is None: | |
151 | if i >= np: raise U.ExpectedError, (404, 'Missing user name') | |
152 | expuser = CGI.PATH[i] | |
153 | i += 1 | |
154 | ||
a2916c06 MW |
155 | ## If there's no token cookie, then we have to bail. |
156 | try: token = CGI.COOKIE['chpwd-token'] | |
157 | except KeyError: | |
158 | CGI.redirect(CGI.action('login', why = 'NOAUTH')) | |
159 | return | |
160 | ||
161 | ## If we only want read-only access, then the cookie is good enough. | |
162 | ## Otherwise we must check that a nonce was supplied, and that it is | |
163 | ## correct. | |
164 | if ctx == 'cgi-query': | |
165 | nonce = None | |
166 | else: | |
167 | nonce = CGI.SPECIAL['%nonce'] | |
168 | if not nonce: | |
169 | CGI.redirect(CGI.action('login', why = 'NONONCE')) | |
170 | return | |
171 | ||
172 | ## Verify the token and nonce. | |
173 | try: | |
174 | CU.USER = HA.check_auth(token, nonce) | |
175 | except HA.AuthenticationFailed, e: | |
176 | CGI.redirect(CGI.action('login', why = e.why)) | |
177 | return | |
ba8f1b92 MW |
178 | if CU.USER != expuser: raise U.ExpectedError, (401, 'User mismatch') |
179 | CGI.STATE.kw['user'] = CU.USER | |
a2916c06 MW |
180 | |
181 | ## Invoke the subcommand handler. | |
182 | c.cgi(CGI.PARAM, CGI.PATH[i:]) | |
183 | ||
184 | ###-------------------------------------------------------------------------- | |
185 | ### Main dispatch. | |
186 | ||
187 | @CTX.contextmanager | |
188 | def cli_errors(): | |
189 | """Catch expected errors and report them in the traditional Unix style.""" | |
190 | try: | |
191 | yield None | |
192 | except U.ExpectedError, e: | |
193 | SYS.stderr.write('%s: %s\n' % (OS.path.basename(SYS.argv[0]), e.msg)) | |
194 | if 400 <= e.code < 500: SYS.exit(1) | |
195 | else: SYS.exit(2) | |
196 | ||
197 | ### Main dispatch. | |
198 | ||
199 | if __name__ == '__main__': | |
200 | ||
201 | if 'REQUEST_METHOD' in ENV: | |
202 | ## This looks like a CGI request. The heavy lifting for authentication | |
203 | ## over HTTP is done in `dispatch_cgi'. | |
204 | ||
205 | with OUT.redirect_to(CGI.HTTPOutput()): | |
206 | with CGI.cgi_errors(cgi_setup): dispatch_cgi() | |
207 | ||
208 | elif 'USERV_SERVICE' in ENV: | |
209 | ## This is a Userv request. The caller's user name is helpfully in the | |
210 | ## `USERV_USER' environment variable. | |
211 | ||
212 | with cli_errors(): | |
213 | OPTS, args = OPTPARSE.parse_args() | |
214 | CONF.loadconfig(OPTS.config) | |
215 | try: CU.set_user(ENV['USERV_USER']) | |
216 | except KeyError: raise ExpectedError, (500, 'USERV_USER unset') | |
217 | with OUT.redirect_to(O.FileOutput()): | |
218 | OPTPARSE.dispatch('userv', [ENV['USERV_SERVICE']] + args) | |
219 | ||
220 | elif 'SSH_ORIGINAL_COMMAND' in ENV: | |
221 | ## This looks like an SSH request; but we present two different | |
222 | ## interfaces over SSH. We must distinguish them -- carefully: they have | |
223 | ## very different error-reporting conventions. | |
224 | ||
225 | def ssh_setup(): | |
226 | """Extract and parse the client's request from where SSH left it.""" | |
227 | global OPTS | |
228 | OPTS, args = OPTPARSE.parse_args() | |
229 | CONF.loadconfig(OPTS.config) | |
230 | cmd = SL.split(ENV['SSH_ORIGINAL_COMMAND']) | |
231 | if args: raise ExpectedError, (500, 'Unexpected arguments via SSH') | |
232 | return cmd | |
233 | ||
234 | if 'CHPWD_SSH_USER' in ENV: | |
235 | ## Setting `CHPWD_SSH_USER' to a user name is the administrator's way | |
236 | ## of telling us that this is a user request, so treat it like Userv. | |
237 | ||
238 | with cli_errors(): | |
239 | cmd = ssh_setup() | |
240 | CU.set_user(ENV['CHPWD_SSH_USER']) | |
241 | SERVICES['master'].find(USER) | |
242 | with OUT.redirect_to(O.FileOutput()): | |
243 | OPTPARSE.dispatch('userv', cmd) | |
244 | ||
245 | elif 'CHPWD_SSH_MASTER' in ENV: | |
246 | ## Setting `CHPWD_SSH_MASTER' to anything tells us that the client is | |
247 | ## making a remote-service request. We must turn on the protocol | |
248 | ## decoration machinery, but don't need to -- mustn't, indeed -- set up | |
249 | ## a user. | |
250 | ||
251 | try: | |
252 | cmd = ssh_setup() | |
253 | with OUT.redirect_to(O.RemoteOutput()): | |
254 | OPTPARSE.dispatch('remote', map(urldecode, cmd)) | |
255 | except ExpectedError, e: | |
256 | print 'ERR', e.code, e.msg | |
257 | else: | |
258 | print 'OK' | |
259 | ||
260 | else: | |
261 | ## There's probably some strange botch in the `.ssh/authorized_keys' | |
262 | ## file, but we can't do much about it from here. | |
263 | ||
264 | with cli_errors(): | |
265 | raise ExpectedError, (400, "Unabled to determine SSH context") | |
266 | ||
267 | else: | |
268 | ## Plain old command line, apparently. We default to administration | |
269 | ## commands, but allow any kind, since this is useful for debugging, and | |
270 | ## this isn't a security problem since our caller is just as privileged | |
271 | ## as we are. | |
272 | ||
273 | with cli_errors(): | |
274 | OPTS, args = OPTPARSE.parse_args() | |
275 | CONF.loadconfig(OPTS.config) | |
bb623e8f | 276 | CGI.SSLP = OPTS.sslp |
a2916c06 MW |
277 | ctx = OPTS.context |
278 | if OPTS.user: | |
279 | CU.set_user(OPTS.user) | |
280 | if ctx is None: ctx = 'userv' | |
281 | else: | |
282 | D.opendb() | |
283 | if ctx is None: ctx = 'admin' | |
284 | with OUT.redirect_to(O.FileOutput()): | |
285 | OPTPARSE.dispatch(ctx, args) | |
286 | ||
287 | ###----- That's all, folks -------------------------------------------------- |