Commit | Line | Data |
---|---|---|
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 | |
71d74dcf | 41 | import service as S |
a2916c06 MW |
42 | import subcommand as SC |
43 | import util as U | |
44 | ||
45 | for i in ['admin', 'cgi', 'remote', 'user']: | |
46 | __import__('cmd-' + i) | |
47 | ||
48 | ###-------------------------------------------------------------------------- | |
49 | ### Parsing command-line options. | |
50 | ||
51 | ## Command-line options parser. | |
52 | OPTPARSE = SC.SubcommandOptionParser( | |
53 | usage = '%prog SUBCOMMAND [ARGS ...]', | |
54 | version = '%%prog, verion %s' % VERSION, | |
55 | contexts = ['admin', 'userv', 'remote', 'cgi', 'cgi-query', 'cgi-noauth'], | |
56 | commands = SC.COMMANDS, | |
57 | description = """\ | |
58 | Manage all of those annoying passwords. | |
59 | ||
60 | This is free software, and you can redistribute it and/or modify it | |
61 | under the terms of the GNU Affero General Public License | |
62 | <http://www.gnu.org/licenses/agpl-3.0.html>. For a `.tar.gz' file | |
63 | of the source code, use the `source' command. | |
64 | """) | |
65 | ||
66 | OPTS = None | |
67 | ||
68 | ## Set up the global options. | |
69 | for short, long, props in [ | |
70 | ('-c', '--context', { | |
71 | 'metavar': 'CONTEXT', 'dest': 'context', 'default': None, | |
72 | 'help': 'run commands with the given CONTEXT' }), | |
73 | ('-f', '--config-file', { | |
74 | 'metavar': 'FILE', 'dest': 'config', | |
2a875c57 MW |
75 | 'default': ENV.get('CHPWD_CONFIG', |
76 | OS.path.join(HOME, 'chpwd.conf')), | |
a2916c06 | 77 | 'help': 'read configuration from FILE.' }), |
bb623e8f MW |
78 | ('-s', '--ssl', { |
79 | 'dest': 'sslp', 'action': 'store_true', | |
80 | 'help': 'pretend CGI connection is carried over SSL/TLS' }), | |
a2916c06 MW |
81 | ('-u', '--user', { |
82 | 'metavar': 'USER', 'dest': 'user', 'default': None, | |
83 | 'help': "impersonate USER, and default context to `userv'." })]: | |
84 | OPTPARSE.add_option(short, long, **props) | |
85 | ||
86 | ###-------------------------------------------------------------------------- | |
87 | ### CGI dispatch. | |
88 | ||
89 | ## The special variables, to be picked out by `cgiparse'. | |
90 | CGI.SPECIAL['%act'] = None | |
91 | CGI.SPECIAL['%nonce'] = None | |
ba8f1b92 | 92 | CGI.SPECIAL['%user'] = None |
a2916c06 MW |
93 | |
94 | ## We don't want to parse arguments until we've settled on a context; but | |
95 | ## issuing redirects in the early setup phase fails because we don't know | |
96 | ## the script name. So package the setup here. | |
97 | def cgi_setup(ctx = 'cgi-noauth'): | |
98 | global OPTS | |
99 | if OPTS: return | |
100 | OPTPARSE.context = ctx | |
101 | OPTS, args = OPTPARSE.parse_args() | |
102 | if args: raise U.ExpectedError, (500, 'Unexpected arguments to CGI') | |
103 | CONF.loadconfig(OPTS.config) | |
104 | D.opendb() | |
105 | ||
106 | def dispatch_cgi(): | |
107 | """Examine the CGI request and invoke the appropriate command.""" | |
108 | ||
109 | ## Start by picking apart the request. | |
110 | CGI.cgiparse() | |
111 | ||
112 | ## We'll be taking items off the trailing path. | |
113 | i, np = 0, len(CGI.PATH) | |
114 | ||
115 | ## Sometimes, we want to run several actions out of the same form, so the | |
116 | ## subcommand name needs to be in the query string. We use the special | |
117 | ## variable `%act' for this. If it's not set, then we use the first elment | |
118 | ## of the path. | |
119 | act = CGI.SPECIAL['%act'] | |
120 | if act is None: | |
121 | if i >= np: | |
122 | cgi_setup() | |
123 | CGI.redirect(CGI.action('login')) | |
124 | return | |
125 | act = CGI.PATH[i] | |
126 | i += 1 | |
127 | ||
128 | ## Figure out which context we're meant to be operating in, according to | |
129 | ## the requested action. Unknown actions result in an error here; known | |
130 | ## actions where we don't have enough authorization send the user back to | |
131 | ## the login page. | |
132 | for ctx in ['cgi-noauth', 'cgi-query', 'cgi']: | |
133 | try: | |
134 | c = OPTPARSE.lookup_subcommand(act, exactp = True, context = ctx) | |
135 | except U.ExpectedError, e: | |
136 | if e.code != 404: raise | |
137 | else: | |
138 | break | |
139 | else: | |
140 | raise e | |
141 | ||
142 | ## Parse the command line, and load configuration. | |
143 | cgi_setup(ctx) | |
144 | ||
145 | ## Check whether we have enough authorization. There's always enough for | |
146 | ## `cgi-noauth'. | |
147 | if ctx != 'cgi-noauth': | |
148 | ||
ba8f1b92 MW |
149 | ## The next part of the URL should be the user name, so that caches don't |
150 | ## cross things over. | |
151 | expuser = CGI.SPECIAL['%user'] | |
152 | if expuser is None: | |
153 | if i >= np: raise U.ExpectedError, (404, 'Missing user name') | |
154 | expuser = CGI.PATH[i] | |
155 | i += 1 | |
156 | ||
a2916c06 MW |
157 | ## If there's no token cookie, then we have to bail. |
158 | try: token = CGI.COOKIE['chpwd-token'] | |
159 | except KeyError: | |
160 | CGI.redirect(CGI.action('login', why = 'NOAUTH')) | |
161 | return | |
162 | ||
163 | ## If we only want read-only access, then the cookie is good enough. | |
164 | ## Otherwise we must check that a nonce was supplied, and that it is | |
165 | ## correct. | |
166 | if ctx == 'cgi-query': | |
167 | nonce = None | |
168 | else: | |
169 | nonce = CGI.SPECIAL['%nonce'] | |
170 | if not nonce: | |
171 | CGI.redirect(CGI.action('login', why = 'NONONCE')) | |
172 | return | |
173 | ||
174 | ## Verify the token and nonce. | |
175 | try: | |
176 | CU.USER = HA.check_auth(token, nonce) | |
177 | except HA.AuthenticationFailed, e: | |
178 | CGI.redirect(CGI.action('login', why = e.why)) | |
179 | return | |
ba8f1b92 MW |
180 | if CU.USER != expuser: raise U.ExpectedError, (401, 'User mismatch') |
181 | CGI.STATE.kw['user'] = CU.USER | |
a2916c06 MW |
182 | |
183 | ## Invoke the subcommand handler. | |
184 | c.cgi(CGI.PARAM, CGI.PATH[i:]) | |
185 | ||
186 | ###-------------------------------------------------------------------------- | |
187 | ### Main dispatch. | |
188 | ||
189 | @CTX.contextmanager | |
190 | def cli_errors(): | |
191 | """Catch expected errors and report them in the traditional Unix style.""" | |
192 | try: | |
193 | yield None | |
194 | except U.ExpectedError, e: | |
195 | SYS.stderr.write('%s: %s\n' % (OS.path.basename(SYS.argv[0]), e.msg)) | |
196 | if 400 <= e.code < 500: SYS.exit(1) | |
197 | else: SYS.exit(2) | |
198 | ||
199 | ### Main dispatch. | |
200 | ||
201 | if __name__ == '__main__': | |
202 | ||
203 | if 'REQUEST_METHOD' in ENV: | |
204 | ## This looks like a CGI request. The heavy lifting for authentication | |
205 | ## over HTTP is done in `dispatch_cgi'. | |
206 | ||
207 | with OUT.redirect_to(CGI.HTTPOutput()): | |
208 | with CGI.cgi_errors(cgi_setup): dispatch_cgi() | |
209 | ||
210 | elif 'USERV_SERVICE' in ENV: | |
211 | ## This is a Userv request. The caller's user name is helpfully in the | |
212 | ## `USERV_USER' environment variable. | |
213 | ||
214 | with cli_errors(): | |
215 | OPTS, args = OPTPARSE.parse_args() | |
216 | CONF.loadconfig(OPTS.config) | |
217 | try: CU.set_user(ENV['USERV_USER']) | |
218 | except KeyError: raise ExpectedError, (500, 'USERV_USER unset') | |
219 | with OUT.redirect_to(O.FileOutput()): | |
220 | OPTPARSE.dispatch('userv', [ENV['USERV_SERVICE']] + args) | |
221 | ||
222 | elif 'SSH_ORIGINAL_COMMAND' in ENV: | |
223 | ## This looks like an SSH request; but we present two different | |
224 | ## interfaces over SSH. We must distinguish them -- carefully: they have | |
225 | ## very different error-reporting conventions. | |
226 | ||
227 | def ssh_setup(): | |
228 | """Extract and parse the client's request from where SSH left it.""" | |
229 | global OPTS | |
230 | OPTS, args = OPTPARSE.parse_args() | |
231 | CONF.loadconfig(OPTS.config) | |
232 | cmd = SL.split(ENV['SSH_ORIGINAL_COMMAND']) | |
71d74dcf | 233 | if args: raise U.ExpectedError, (500, 'Unexpected arguments via SSH') |
a2916c06 MW |
234 | return cmd |
235 | ||
236 | if 'CHPWD_SSH_USER' in ENV: | |
237 | ## Setting `CHPWD_SSH_USER' to a user name is the administrator's way | |
238 | ## of telling us that this is a user request, so treat it like Userv. | |
239 | ||
240 | with cli_errors(): | |
241 | cmd = ssh_setup() | |
242 | CU.set_user(ENV['CHPWD_SSH_USER']) | |
71d74dcf | 243 | S.SERVICES['master'].find(CU.USER) |
a2916c06 MW |
244 | with OUT.redirect_to(O.FileOutput()): |
245 | OPTPARSE.dispatch('userv', cmd) | |
246 | ||
247 | elif 'CHPWD_SSH_MASTER' in ENV: | |
248 | ## Setting `CHPWD_SSH_MASTER' to anything tells us that the client is | |
249 | ## making a remote-service request. We must turn on the protocol | |
250 | ## decoration machinery, but don't need to -- mustn't, indeed -- set up | |
251 | ## a user. | |
252 | ||
253 | try: | |
254 | cmd = ssh_setup() | |
255 | with OUT.redirect_to(O.RemoteOutput()): | |
71d74dcf MW |
256 | OPTPARSE.dispatch('remote', map(CGI.urldecode, cmd)) |
257 | except U.ExpectedError, e: | |
a2916c06 MW |
258 | print 'ERR', e.code, e.msg |
259 | else: | |
260 | print 'OK' | |
261 | ||
262 | else: | |
263 | ## There's probably some strange botch in the `.ssh/authorized_keys' | |
264 | ## file, but we can't do much about it from here. | |
265 | ||
266 | with cli_errors(): | |
71d74dcf | 267 | raise U.ExpectedError, (400, "Unabled to determine SSH context") |
a2916c06 MW |
268 | |
269 | else: | |
270 | ## Plain old command line, apparently. We default to administration | |
271 | ## commands, but allow any kind, since this is useful for debugging, and | |
272 | ## this isn't a security problem since our caller is just as privileged | |
273 | ## as we are. | |
274 | ||
275 | with cli_errors(): | |
276 | OPTS, args = OPTPARSE.parse_args() | |
277 | CONF.loadconfig(OPTS.config) | |
bb623e8f | 278 | CGI.SSLP = OPTS.sslp |
a2916c06 MW |
279 | ctx = OPTS.context |
280 | if OPTS.user: | |
281 | CU.set_user(OPTS.user) | |
ea3f041b | 282 | CGI.STATE.kw['user'] = OPTS.user |
a2916c06 MW |
283 | if ctx is None: ctx = 'userv' |
284 | else: | |
285 | D.opendb() | |
286 | if ctx is None: ctx = 'admin' | |
287 | with OUT.redirect_to(O.FileOutput()): | |
288 | OPTPARSE.dispatch(ctx, args) | |
289 | ||
290 | ###----- That's all, folks -------------------------------------------------- |