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d1c45f5c MW |
1 | ### -*-python-*- |
2 | ### | |
3 | ### Management of a secure password database | |
4 | ### | |
5 | ### (c) 2005 Straylight/Edgeware | |
6 | ### | |
7 | ||
8 | ###----- Licensing notice --------------------------------------------------- | |
9 | ### | |
10 | ### This file is part of the Python interface to Catacomb. | |
11 | ### | |
12 | ### Catacomb/Python is free software; you can redistribute it and/or modify | |
13 | ### it under the terms of the GNU General Public License as published by | |
14 | ### the Free Software Foundation; either version 2 of the License, or | |
15 | ### (at your option) any later version. | |
16 | ### | |
17 | ### Catacomb/Python 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 General Public License for more details. | |
21 | ### | |
22 | ### You should have received a copy of the GNU General Public License along | |
23 | ### with Catacomb/Python; if not, write to the Free Software Foundation, | |
24 | ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. | |
25 | ||
26 | ###-------------------------------------------------------------------------- | |
27 | ### Imported modules. | |
43c09851 | 28 | |
494b719c MW |
29 | from __future__ import with_statement |
30 | ||
af861fb7 | 31 | import errno as _E |
6baae405 | 32 | import os as _OS |
af861fb7 | 33 | from cStringIO import StringIO as _StringIO |
6baae405 | 34 | |
43c09851 | 35 | import catacomb as _C |
d1c45f5c MW |
36 | |
37 | ###-------------------------------------------------------------------------- | |
f6d012db MW |
38 | ### Python version portability. |
39 | ||
40 | def _excval(): return _SYS.exc_info()[1] | |
41 | ||
42 | ###-------------------------------------------------------------------------- | |
af861fb7 MW |
43 | ### Text encoding utilities. |
44 | ||
45 | def _literalp(s): | |
46 | """ | |
47 | Answer whether S can be represented literally. | |
48 | ||
49 | If True, then S can be stored literally, as a metadata item name or | |
50 | value; if False, then S requires some kind of encoding. | |
51 | """ | |
52 | return all(ch.isalnum() or ch in '-_:' for ch in s) | |
53 | ||
54 | def _enc_metaname(name): | |
55 | """Encode NAME as a metadata item name, returning the result.""" | |
56 | if _literalp(name): | |
57 | return name | |
58 | else: | |
59 | sio = _StringIO() | |
60 | sio.write('!') | |
61 | for ch in name: | |
62 | if _literalp(ch): sio.write(ch) | |
63 | elif ch == ' ': sio.write('+') | |
64 | else: sio.write('%%%02x' % ord(ch)) | |
65 | return sio.getvalue() | |
66 | ||
67 | def _dec_metaname(name): | |
68 | """Decode NAME as a metadata item name, returning the result.""" | |
69 | if not name.startswith('!'): | |
70 | return name | |
71 | else: | |
72 | sio = _StringIO() | |
73 | i, n = 1, len(name) | |
74 | while i < n: | |
75 | ch = name[i] | |
76 | i += 1 | |
77 | if ch == '+': | |
78 | sio.write(' ') | |
79 | elif ch == '%': | |
80 | sio.write(chr(int(name[i:i + 2], 16))) | |
81 | i += 2 | |
82 | else: | |
83 | sio.write(ch) | |
84 | return sio.getvalue() | |
85 | ||
86 | def _b64(s): | |
87 | """Encode S as base64, without newlines, and trimming `=' padding.""" | |
3e80d327 | 88 | return s.encode('base64').replace('\n', '').rstrip('=') |
af861fb7 MW |
89 | def _unb64(s): |
90 | """Decode S as base64 with trimmed `=' padding.""" | |
91 | return (s + '='*((4 - len(s))%4)).decode('base64') | |
92 | ||
93 | def _enc_metaval(val): | |
94 | """Encode VAL as a metadata item value, returning the result.""" | |
95 | if _literalp(val): return val | |
96 | else: return '?' + _b64(val) | |
97 | ||
98 | def _dec_metaval(val): | |
99 | """Decode VAL as a metadata item value, returning the result.""" | |
100 | if not val.startswith('?'): return val | |
101 | else: return _unb64(val[1:]) | |
102 | ||
103 | ###-------------------------------------------------------------------------- | |
d1c45f5c MW |
104 | ### Underlying cryptography. |
105 | ||
43c09851 | 106 | class DecryptError (Exception): |
d1c45f5c MW |
107 | """ |
108 | I represent a failure to decrypt a message. | |
109 | ||
110 | Usually this means that someone used the wrong key, though it can also | |
111 | mean that a ciphertext has been modified. | |
112 | """ | |
43c09851 | 113 | pass |
114 | ||
115 | class Crypto (object): | |
d1c45f5c MW |
116 | """ |
117 | I represent a symmetric crypto transform. | |
118 | ||
119 | There's currently only one transform implemented, which is the obvious | |
120 | generic-composition construction: given a message m, and keys K0 and K1, we | |
121 | choose an IV v, and compute: | |
122 | ||
123 | * y = v || E(K0, v; m) | |
124 | * t = M(K1; y) | |
125 | ||
126 | The final ciphertext is t || y. | |
127 | """ | |
128 | ||
43c09851 | 129 | def __init__(me, c, h, m, ck, mk): |
d1c45f5c MW |
130 | """ |
131 | Initialize the Crypto object with a given algorithm selection and keys. | |
132 | ||
133 | We need a GCipher subclass C, a GHash subclass H, a GMAC subclass M, and | |
134 | keys CK and MK for C and M respectively. | |
135 | """ | |
43c09851 | 136 | me.c = c(ck) |
137 | me.m = m(mk) | |
138 | me.h = h | |
d1c45f5c | 139 | |
43c09851 | 140 | def encrypt(me, pt): |
d1c45f5c MW |
141 | """ |
142 | Encrypt the message PT and return the resulting ciphertext. | |
143 | """ | |
9a7b948f MW |
144 | blksz = me.c.__class__.blksz |
145 | b = _C.WriteBuffer() | |
146 | if blksz: | |
147 | iv = _C.rand.block(blksz) | |
43c09851 | 148 | me.c.setiv(iv) |
9a7b948f MW |
149 | b.put(iv) |
150 | b.put(me.c.encrypt(pt)) | |
151 | t = me.m().hash(b).done() | |
152 | return t + str(buffer(b)) | |
153 | ||
43c09851 | 154 | def decrypt(me, ct): |
d1c45f5c MW |
155 | """ |
156 | Decrypt the ciphertext CT, returning the plaintext. | |
157 | ||
158 | Raises DecryptError if anything goes wrong. | |
159 | """ | |
9a7b948f MW |
160 | blksz = me.c.__class__.blksz |
161 | tagsz = me.m.__class__.tagsz | |
162 | b = _C.ReadBuffer(ct) | |
163 | t = b.get(tagsz) | |
164 | h = me.m() | |
165 | if blksz: | |
166 | iv = b.get(blksz) | |
167 | me.c.setiv(iv) | |
168 | h.hash(iv) | |
169 | x = b.get(b.left) | |
170 | h.hash(x) | |
171 | if t != h.done(): raise DecryptError | |
172 | return me.c.decrypt(x) | |
b2687a0a | 173 | |
43c09851 | 174 | class PPK (Crypto): |
d1c45f5c MW |
175 | """ |
176 | I represent a crypto transform whose keys are derived from a passphrase. | |
177 | ||
178 | The password is salted and hashed; the salt is available as the `salt' | |
179 | attribute. | |
180 | """ | |
181 | ||
43c09851 | 182 | def __init__(me, pp, c, h, m, salt = None): |
d1c45f5c MW |
183 | """ |
184 | Initialize the PPK object with a passphrase and algorithm selection. | |
185 | ||
186 | We want a passphrase PP, a GCipher subclass C, a GHash subclass H, a GMAC | |
187 | subclass M, and a SALT. The SALT may be None, if we're generating new | |
188 | keys, indicating that a salt should be chosen randomly. | |
189 | """ | |
43c09851 | 190 | if not salt: salt = _C.rand.block(h.hashsz) |
191 | tag = '%s\0%s' % (pp, salt) | |
192 | Crypto.__init__(me, c, h, m, | |
d1c45f5c MW |
193 | h().hash('cipher:' + tag).done(), |
194 | h().hash('mac:' + tag).done()) | |
43c09851 | 195 | me.salt = salt |
196 | ||
d1c45f5c | 197 | ###-------------------------------------------------------------------------- |
494b719c MW |
198 | ### Backend storage. |
199 | ||
6baae405 MW |
200 | class StorageBackendRefusal (Exception): |
201 | """ | |
202 | I signify that a StorageBackend subclass has refused to open a file. | |
203 | ||
204 | This is used by the StorageBackend.open class method. | |
205 | """ | |
206 | pass | |
207 | ||
208 | class StorageBackendClass (type): | |
209 | """ | |
210 | I am a metaclass for StorageBackend classes. | |
211 | ||
212 | My main feature is that I register my concrete instances (with a `NAME' | |
213 | which is not `None') with the StorageBackend class. | |
214 | """ | |
215 | def __init__(me, name, supers, dict): | |
216 | """ | |
217 | Register a new concrete StorageBackend subclass. | |
218 | """ | |
219 | super(StorageBackendClass, me).__init__(name, supers, dict) | |
220 | if me.NAME is not None: StorageBackend.register_concrete_subclass(me) | |
221 | ||
494b719c MW |
222 | class StorageBackend (object): |
223 | """ | |
1726ab40 MW |
224 | I provide basic protocol for password storage backends. |
225 | ||
226 | I'm an abstract class: you want one of my subclasses if you actually want | |
6baae405 MW |
227 | to do something useful. But I maintain a list of my subclasses and can |
228 | choose an appropriate one to open a database file you've found lying about. | |
494b719c MW |
229 | |
230 | Backends are responsible for storing and retrieving stuff, but not for the | |
231 | cryptographic details. Backends need to store two kinds of information: | |
232 | ||
233 | * metadata, consisting of a number of property names and their values; | |
234 | and | |
235 | ||
236 | * password mappings, consisting of a number of binary labels and | |
237 | payloads. | |
1726ab40 MW |
238 | |
239 | Backends need to implement the following ordinary methods. See the calling | |
240 | methods for details of the subclass responsibilities. | |
241 | ||
242 | BE._create(FILE) Create a new database in FILE; used by `create'. | |
243 | ||
244 | BE._open(FILE, WRITEP) | |
245 | Open the existing database FILE; used by `open'. | |
246 | ||
053c2659 MW |
247 | BE._close(ABRUPTP) Close the database, freeing up any resources. If |
248 | ABRUPTP then don't try to commit changes. | |
1726ab40 MW |
249 | |
250 | BE._get_meta(NAME, DEFAULT) | |
251 | Return the value of the metadata item with the given | |
252 | NAME, or DEFAULT if it doesn't exist; used by | |
253 | `get_meta'. | |
254 | ||
255 | BE._put_meta(NAME, VALUE) | |
256 | Set the VALUE of the metadata item with the given | |
257 | NAME, creating one if necessary; used by `put_meta'. | |
258 | ||
259 | BE._del_meta(NAME) Forget the metadata item with the given NAME; raise | |
260 | `KeyError' if there is no such item; used by | |
261 | `del_meta'. | |
262 | ||
263 | BE._iter_meta() Return an iterator over the metadata (NAME, VALUE) | |
264 | pairs; used by `iter_meta'. | |
265 | ||
266 | BE._get_passwd(LABEL) | |
267 | Return the password payload stored with the (binary) | |
268 | LABEL; used by `get_passwd'. | |
269 | ||
270 | BE._put_passwd(LABEL, PAYLOAD) | |
271 | Associate the (binary) PAYLOAD with the LABEL, | |
272 | forgetting any previous payload for that LABEL; used | |
273 | by `put_passwd'. | |
274 | ||
275 | BE._del_passwd(LABEL) Forget the password record with the given LABEL; used | |
276 | by `_del_passwd'. | |
277 | ||
278 | BE._iter_passwds() Return an iterator over the password (LABEL, PAYLOAD) | |
279 | pairs; used by `iter_passwds'. | |
6baae405 MW |
280 | |
281 | Also, concrete subclasses should define the following class attributes. | |
282 | ||
283 | NAME The name of the backend, so that the user can select | |
284 | it when creating a new database. | |
285 | ||
286 | PRIO An integer priority: backends are tried in decreasing | |
287 | priority order when opening an existing database. | |
494b719c MW |
288 | """ |
289 | ||
6baae405 MW |
290 | __metaclass__ = StorageBackendClass |
291 | NAME = None | |
292 | PRIO = 10 | |
293 | ||
294 | ## The registry of subclasses. | |
295 | CLASSES = {} | |
296 | ||
494b719c MW |
297 | FAIL = ['FAIL'] |
298 | ||
6baae405 MW |
299 | @staticmethod |
300 | def register_concrete_subclass(sub): | |
301 | """Register a concrete subclass, so that `open' can try it.""" | |
302 | StorageBackend.CLASSES[sub.NAME] = sub | |
303 | ||
304 | @staticmethod | |
305 | def byname(name): | |
306 | """ | |
307 | Return the concrete subclass with the given NAME. | |
308 | ||
309 | Raise `KeyError' if the name isn't found. | |
310 | """ | |
311 | return StorageBackend.CLASSES[name] | |
312 | ||
313 | @staticmethod | |
314 | def classes(): | |
315 | """Return an iterator over the concrete subclasses.""" | |
316 | return StorageBackend.CLASSES.itervalues() | |
317 | ||
318 | @staticmethod | |
319 | def open(file, writep = False): | |
320 | """Open a database FILE, using some appropriate backend.""" | |
321 | _OS.stat(file) | |
322 | for cls in sorted(StorageBackend.CLASSES.values(), reverse = True, | |
323 | key = lambda cls: cls.PRIO): | |
324 | try: return cls(file, writep) | |
325 | except StorageBackendRefusal: pass | |
326 | raise StorageBackendRefusal | |
494b719c MW |
327 | |
328 | @classmethod | |
329 | def create(cls, file): | |
1726ab40 MW |
330 | """ |
331 | Create a new database in the named FILE, using this backend. | |
332 | ||
333 | Subclasses must implement the `_create' instance method. | |
334 | """ | |
494b719c | 335 | return cls(writep = True, _magic = lambda me: me._create(file)) |
494b719c MW |
336 | |
337 | def __init__(me, file = None, writep = False, _magic = None, *args, **kw): | |
338 | """ | |
339 | Main constructor. | |
1726ab40 MW |
340 | |
341 | Subclasses are not, in general, expected to override this: there's a | |
342 | somewhat hairy protocol between the constructor and some of the class | |
343 | methods. Instead, the main hook for customization is the subclass's | |
344 | `_open' method, which is invoked in the usual case. | |
494b719c MW |
345 | """ |
346 | super(StorageBackend, me).__init__(*args, **kw) | |
1c7419c9 | 347 | if me.NAME is None: raise ValueError('abstract class') |
494b719c | 348 | if _magic is not None: _magic(me) |
1c7419c9 | 349 | elif file is None: raise ValueError('missing file parameter') |
1726ab40 | 350 | else: me._open(file, writep) |
494b719c MW |
351 | me._writep = writep |
352 | me._livep = True | |
353 | ||
053c2659 | 354 | def close(me, abruptp = False): |
494b719c MW |
355 | """ |
356 | Close the database. | |
357 | ||
358 | It is harmless to attempt to close a database which has been closed | |
1726ab40 | 359 | already. Calls the subclass's `_close' method. |
494b719c MW |
360 | """ |
361 | if me._livep: | |
362 | me._livep = False | |
053c2659 | 363 | me._close(abruptp) |
494b719c MW |
364 | |
365 | ## Utilities. | |
366 | ||
367 | def _check_live(me): | |
368 | """Raise an error if the receiver has been closed.""" | |
1c7419c9 | 369 | if not me._livep: raise ValueError('database is closed') |
494b719c MW |
370 | |
371 | def _check_write(me): | |
372 | """Raise an error if the receiver is not open for writing.""" | |
373 | me._check_live() | |
1c7419c9 | 374 | if not me._writep: raise ValueError('database is read-only') |
494b719c MW |
375 | |
376 | def _check_meta_name(me, name): | |
377 | """ | |
378 | Raise an error unless NAME is a valid name for a metadata item. | |
379 | ||
380 | Metadata names may not start with `$': such names are reserved for | |
381 | password storage. | |
382 | """ | |
383 | if name.startswith('$'): | |
1c7419c9 | 384 | raise ValueError("invalid metadata key `%s'" % name) |
494b719c MW |
385 | |
386 | ## Context protocol. | |
387 | ||
388 | def __enter__(me): | |
389 | """Context protocol: make sure the database is closed on exit.""" | |
390 | return me | |
391 | def __exit__(me, exctype, excvalue, exctb): | |
392 | """Context protocol: see `__enter__'.""" | |
053c2659 | 393 | me.close(excvalue is not None) |
494b719c MW |
394 | |
395 | ## Metadata. | |
396 | ||
397 | def get_meta(me, name, default = FAIL): | |
398 | """ | |
399 | Fetch the value for the metadata item NAME. | |
400 | ||
401 | If no such item exists, then return DEFAULT if that was set; otherwise | |
402 | raise a `KeyError'. | |
1726ab40 MW |
403 | |
404 | This calls the subclass's `_get_meta' method, which should return the | |
405 | requested item or return the given DEFAULT value. It may assume that the | |
406 | name is valid and the database is open. | |
494b719c MW |
407 | """ |
408 | me._check_meta_name(name) | |
409 | me._check_live() | |
1726ab40 | 410 | value = me._get_meta(name, default) |
1c7419c9 | 411 | if value is StorageBackend.FAIL: raise KeyError(name) |
494b719c MW |
412 | return value |
413 | ||
414 | def put_meta(me, name, value): | |
1726ab40 MW |
415 | """ |
416 | Store VALUE in the metadata item called NAME. | |
417 | ||
418 | This calls the subclass's `_put_meta' method, which may assume that the | |
419 | name is valid and the database is open for writing. | |
420 | """ | |
494b719c MW |
421 | me._check_meta_name(name) |
422 | me._check_write() | |
1726ab40 | 423 | me._put_meta(name, value) |
494b719c MW |
424 | |
425 | def del_meta(me, name): | |
1726ab40 MW |
426 | """ |
427 | Forget about the metadata item with the given NAME. | |
428 | ||
429 | This calls the subclass's `_del_meta' method, which may assume that the | |
430 | name is valid and the database is open for writing. | |
431 | """ | |
494b719c MW |
432 | me._check_meta_name(name) |
433 | me._check_write() | |
1726ab40 | 434 | me._del_meta(name) |
494b719c MW |
435 | |
436 | def iter_meta(me): | |
1726ab40 MW |
437 | """ |
438 | Return an iterator over the name/value metadata items. | |
494b719c | 439 | |
1726ab40 MW |
440 | This calls the subclass's `_iter_meta' method, which may assume that the |
441 | database is open. | |
442 | """ | |
443 | me._check_live() | |
444 | return me._iter_meta() | |
494b719c MW |
445 | |
446 | def get_passwd(me, label): | |
447 | """ | |
448 | Fetch and return the payload stored with the (opaque, binary) LABEL. | |
449 | ||
450 | If there is no such payload then raise `KeyError'. | |
1726ab40 MW |
451 | |
452 | This calls the subclass's `_get_passwd' method, which may assume that the | |
453 | database is open. | |
494b719c MW |
454 | """ |
455 | me._check_live() | |
1726ab40 | 456 | return me._get_passwd(label) |
494b719c MW |
457 | |
458 | def put_passwd(me, label, payload): | |
459 | """ | |
460 | Associate the (opaque, binary) PAYLOAD with the (opaque, binary) LABEL. | |
461 | ||
462 | Any previous payload for LABEL is forgotten. | |
1726ab40 MW |
463 | |
464 | This calls the subclass's `_put_passwd' method, which may assume that the | |
465 | database is open for writing. | |
494b719c MW |
466 | """ |
467 | me._check_write() | |
1726ab40 | 468 | me._put_passwd(label, payload) |
494b719c MW |
469 | |
470 | def del_passwd(me, label): | |
471 | """ | |
472 | Forget any PAYLOAD associated with the (opaque, binary) LABEL. | |
473 | ||
474 | If there is no such payload then raise `KeyError'. | |
1726ab40 MW |
475 | |
476 | This calls the subclass's `_del_passwd' method, which may assume that the | |
477 | database is open for writing. | |
494b719c MW |
478 | """ |
479 | me._check_write() | |
1d93191e | 480 | me._del_passwd(label) |
494b719c MW |
481 | |
482 | def iter_passwds(me): | |
1726ab40 MW |
483 | """ |
484 | Return an iterator over the stored password label/payload pairs. | |
485 | ||
486 | This calls the subclass's `_iter_passwds' method, which may assume that | |
487 | the database is open. | |
488 | """ | |
494b719c | 489 | me._check_live() |
1726ab40 MW |
490 | return me._iter_passwds() |
491 | ||
8501dc39 MW |
492 | try: import gdbm as _G |
493 | except ImportError: pass | |
494 | else: | |
495 | class GDBMStorageBackend (StorageBackend): | |
496 | """ | |
497 | My instances store password data in a GDBM database. | |
1726ab40 | 498 | |
8501dc39 MW |
499 | Metadata and password entries are mixed into the same database. The key |
500 | for a metadata item is simply its name; the key for a password entry is | |
501 | the entry's label prefixed by `$', since we're guaranteed that no | |
502 | metadata item name begins with `$'. | |
503 | """ | |
1726ab40 | 504 | |
8501dc39 | 505 | NAME = 'gdbm' |
6baae405 | 506 | |
8501dc39 MW |
507 | def _open(me, file, writep): |
508 | try: me._db = _G.open(file, writep and 'w' or 'r') | |
f6d012db | 509 | except _G.error: raise StorageBackendRefusal(_excval()) |
1726ab40 | 510 | |
8501dc39 MW |
511 | def _create(me, file): |
512 | me._db = _G.open(file, 'n', 0600) | |
1726ab40 | 513 | |
8501dc39 MW |
514 | def _close(me, abruptp): |
515 | me._db.close() | |
516 | me._db = None | |
1726ab40 | 517 | |
8501dc39 MW |
518 | def _get_meta(me, name, default): |
519 | try: return me._db[name] | |
520 | except KeyError: return default | |
1726ab40 | 521 | |
8501dc39 MW |
522 | def _put_meta(me, name, value): |
523 | me._db[name] = value | |
1726ab40 | 524 | |
8501dc39 MW |
525 | def _del_meta(me, name): |
526 | del me._db[name] | |
1726ab40 | 527 | |
8501dc39 MW |
528 | def _iter_meta(me): |
529 | k = me._db.firstkey() | |
530 | while k is not None: | |
531 | if not k.startswith('$'): yield k, me._db[k] | |
532 | k = me._db.nextkey(k) | |
1726ab40 | 533 | |
8501dc39 MW |
534 | def _get_passwd(me, label): |
535 | return me._db['$' + label] | |
1726ab40 | 536 | |
8501dc39 MW |
537 | def _put_passwd(me, label, payload): |
538 | me._db['$' + label] = payload | |
1726ab40 | 539 | |
8501dc39 MW |
540 | def _del_passwd(me, label): |
541 | del me._db['$' + label] | |
1726ab40 | 542 | |
8501dc39 MW |
543 | def _iter_passwds(me): |
544 | k = me._db.firstkey() | |
545 | while k is not None: | |
546 | if k.startswith('$'): yield k[1:], me._db[k] | |
547 | k = me._db.nextkey(k) | |
494b719c | 548 | |
e92f9aa2 MW |
549 | try: import sqlite3 as _Q |
550 | except ImportError: pass | |
551 | else: | |
552 | class SQLiteStorageBackend (StorageBackend): | |
553 | """ | |
554 | I represent a password database stored in SQLite. | |
555 | ||
556 | Metadata and password items are stored in separate tables, so there's no | |
557 | conflict. Some additional metadata is stored in the `meta' table, with | |
558 | names beginning with `$' so as not to conflict with clients: | |
559 | ||
560 | $version The schema version of the table. | |
561 | """ | |
562 | ||
563 | NAME = 'sqlite' | |
564 | VERSION = 0 | |
565 | ||
566 | def _open(me, file, writep): | |
567 | try: | |
568 | me._db = _Q.connect(file) | |
569 | ver = me._query_scalar( | |
570 | "SELECT value FROM meta WHERE name = '$version'", | |
571 | "version check") | |
f6d012db MW |
572 | except (_Q.DatabaseError, _Q.OperationalError): |
573 | raise StorageBackendRefusal(_excval()) | |
1c7419c9 | 574 | if ver is None: raise ValueError('database broken (missing $version)') |
e92f9aa2 | 575 | elif ver < me.VERSION: me._upgrade(ver) |
1c7419c9 MW |
576 | elif ver > me.VERSION: raise ValueError \ |
577 | ('unknown database schema version (%d > %d)' % (ver, me.VERSION)) | |
e92f9aa2 MW |
578 | |
579 | def _create(me, file): | |
580 | fd = _OS.open(file, _OS.O_WRONLY | _OS.O_CREAT | _OS.O_EXCL, 0600) | |
581 | _OS.close(fd) | |
582 | try: | |
583 | me._db = _Q.connect(file) | |
584 | c = me._db.cursor() | |
585 | c.execute(""" | |
586 | CREATE TABLE meta ( | |
587 | name TEXT PRIMARY KEY NOT NULL, | |
588 | value BLOB NOT NULL); | |
589 | """) | |
590 | c.execute(""" | |
591 | CREATE TABLE passwd ( | |
592 | label BLOB PRIMARY KEY NOT NULL, | |
593 | payload BLOB NOT NULL); | |
594 | """) | |
595 | c.execute(""" | |
596 | INSERT INTO meta (name, value) VALUES ('$version', ?); | |
597 | """, [me.VERSION]) | |
598 | except: | |
599 | try: _OS.unlink(file) | |
600 | except OSError: pass | |
601 | raise | |
602 | ||
603 | def _upgrade(me, ver): | |
604 | """Upgrade the database from schema version VER.""" | |
605 | assert False, 'how embarrassing' | |
606 | ||
607 | def _close(me, abruptp): | |
608 | if not abruptp: me._db.commit() | |
609 | me._db.close() | |
610 | me._db = None | |
611 | ||
612 | def _fetch_scalar(me, c, what, default = None): | |
613 | try: row = next(c) | |
614 | except StopIteration: val = default | |
615 | else: val, = row | |
616 | try: row = next(c) | |
617 | except StopIteration: pass | |
1c7419c9 | 618 | else: raise ValueError('multiple matching records for %s' % what) |
e92f9aa2 MW |
619 | return val |
620 | ||
621 | def _query_scalar(me, query, what, default = None, args = []): | |
622 | c = me._db.cursor() | |
623 | c.execute(query, args) | |
624 | return me._fetch_scalar(c, what, default) | |
625 | ||
626 | def _get_meta(me, name, default): | |
627 | v = me._query_scalar("SELECT value FROM meta WHERE name = ?", | |
628 | "metadata item `%s'" % name, | |
629 | default = default, args = [name]) | |
630 | if v is default: return v | |
631 | else: return str(v) | |
632 | ||
633 | def _put_meta(me, name, value): | |
634 | c = me._db.cursor() | |
635 | c.execute("INSERT OR REPLACE INTO meta (name, value) VALUES (?, ?)", | |
636 | [name, buffer(value)]) | |
637 | ||
638 | def _del_meta(me, name): | |
639 | c = me._db.cursor() | |
640 | c.execute("DELETE FROM meta WHERE name = ?", [name]) | |
1c7419c9 | 641 | if not c.rowcount: raise KeyError(name) |
e92f9aa2 MW |
642 | |
643 | def _iter_meta(me): | |
644 | c = me._db.cursor() | |
645 | c.execute("SELECT name, value FROM meta WHERE name NOT LIKE '$%'") | |
646 | for k, v in c: yield k, str(v) | |
647 | ||
648 | def _get_passwd(me, label): | |
649 | pld = me._query_scalar("SELECT payload FROM passwd WHERE label = ?", | |
650 | "password", default = None, | |
651 | args = [buffer(label)]) | |
1c7419c9 | 652 | if pld is None: raise KeyError(label) |
e92f9aa2 MW |
653 | return str(pld) |
654 | ||
655 | def _put_passwd(me, label, payload): | |
656 | c = me._db.cursor() | |
657 | c.execute("INSERT OR REPLACE INTO passwd (label, payload) " | |
658 | "VALUES (?, ?)", | |
659 | [buffer(label), buffer(payload)]) | |
660 | ||
661 | def _del_passwd(me, label): | |
662 | c = me._db.cursor() | |
663 | c.execute("DELETE FROM passwd WHERE label = ?", [label]) | |
1c7419c9 | 664 | if not c.rowcount: raise KeyError(label) |
e92f9aa2 MW |
665 | |
666 | def _iter_passwds(me): | |
667 | c = me._db.cursor() | |
668 | c.execute("SELECT label, payload FROM passwd") | |
669 | for k, v in c: yield str(k), str(v) | |
670 | ||
af861fb7 MW |
671 | class PlainTextBackend (StorageBackend): |
672 | """ | |
673 | I'm a utility base class for storage backends which use plain text files. | |
674 | ||
675 | I provide subclasses with the following capabilities. | |
676 | ||
677 | * Creating files, with given modes, optionally ensuring that the file | |
678 | doesn't exist already. | |
679 | ||
680 | * Parsing flat text files, checking leading magic, skipping comments, and | |
681 | providing standard encodings of troublesome characters and binary | |
682 | strings in metadata and password records. See below. | |
683 | ||
684 | * Maintenance of metadata and password records in in-memory dictionaries, | |
685 | with ready implementations of the necessary StorageBackend subclass | |
686 | responsibility methods. (Subclasses can override these if they want to | |
687 | make different arrangements.) | |
688 | ||
689 | Metadata records are written with an optional prefix string chosen by the | |
690 | caller, followed by a `NAME=VALUE' pair. The NAME is form-urlencoded and | |
691 | prefixed with `!' if it contains strange characters; the VALUE is base64- | |
692 | encoded (without the pointless trailing `=' padding) and prefixed with `?' | |
693 | if necessary. | |
694 | ||
695 | Password records are written with an optional prefix string chosen by the | |
696 | caller, followed by a LABEL=PAYLOAD pair, both of which are base64-encoded | |
697 | (without padding). | |
698 | ||
699 | The following attributes are available for subclasses: | |
700 | ||
701 | _meta Dictionary mapping metadata item names to their values. | |
702 | Populated by `_parse_meta' and managed by `_get_meta' and | |
703 | friends. | |
704 | ||
705 | _pw Dictionary mapping password labels to encrypted payloads. | |
706 | Populated by `_parse_passwd' and managed by `_get_passwd' and | |
707 | friends. | |
708 | ||
709 | _dirtyp Boolean: set if either of the dictionaries has been modified. | |
710 | """ | |
711 | ||
712 | def __init__(me, *args, **kw): | |
713 | """ | |
714 | Hook for initialization. | |
715 | ||
716 | Sets up the published instance attributes. | |
717 | """ | |
718 | me._meta = {} | |
719 | me._pw = {} | |
720 | me._dirtyp = False | |
721 | super(PlainTextBackend, me).__init__(*args, **kw) | |
722 | ||
723 | def _create_file(me, file, mode = 0600, freshp = False): | |
724 | """ | |
725 | Make sure FILE exists, creating it with the given MODE if necessary. | |
726 | ||
727 | If FRESHP is true, then make sure the file did not exist previously. | |
728 | Return a file object for the newly created file. | |
729 | """ | |
730 | flags = _OS.O_CREAT | _OS.O_WRONLY | |
731 | if freshp: flags |= _OS.O_EXCL | |
732 | else: flags |= _OS.O_TRUNC | |
733 | fd = _OS.open(file, flags, mode) | |
734 | return _OS.fdopen(fd, 'w') | |
735 | ||
736 | def _mark_dirty(me): | |
737 | """ | |
738 | Set the `_dirtyp' flag. | |
739 | ||
740 | Subclasses might find it useful to intercept this method. | |
741 | """ | |
742 | me._dirtyp = True | |
743 | ||
744 | def _eqsplit(me, line): | |
745 | """ | |
746 | Extract the KEY, VALUE pair from a LINE of the form `KEY=VALUE'. | |
747 | ||
748 | Raise `ValueError' if there is no `=' in the LINE. | |
749 | """ | |
750 | eq = line.index('=') | |
751 | return line[:eq], line[eq + 1:] | |
752 | ||
753 | def _parse_file(me, file, magic = None): | |
754 | """ | |
755 | Parse a FILE. | |
756 | ||
757 | Specifically: | |
758 | ||
759 | * Raise `StorageBackendRefusal' if that the first line doesn't match | |
760 | MAGIC (if provided). MAGIC should not contain the terminating | |
761 | newline. | |
762 | ||
763 | * Ignore comments (beginning `#') and blank lines. | |
764 | ||
765 | * Call `_parse_line' (provided by the subclass) for other lines. | |
766 | """ | |
767 | with open(file, 'r') as f: | |
768 | if magic is not None: | |
769 | if f.readline().rstrip('\n') != magic: raise StorageBackendRefusal | |
770 | for line in f: | |
771 | line = line.rstrip('\n') | |
772 | if not line or line.startswith('#'): continue | |
773 | me._parse_line(line) | |
774 | ||
775 | def _write_file(me, file, writebody, mode = 0600, magic = None): | |
776 | """ | |
777 | Update FILE atomically. | |
778 | ||
779 | The newly created file will have the given MODE. If MAGIC is given, then | |
780 | write that as the first line. Calls WRITEBODY(F) to write the main body | |
781 | of the file where F is a file object for the new file. | |
782 | """ | |
783 | new = file + '.new' | |
784 | with me._create_file(new, mode) as f: | |
785 | if magic is not None: f.write(magic + '\n') | |
786 | writebody(f) | |
787 | _OS.rename(new, file) | |
788 | ||
789 | def _parse_meta(me, line): | |
790 | """Parse LINE as a metadata NAME=VALUE pair, and updates `_meta'.""" | |
791 | k, v = me._eqsplit(line) | |
792 | me._meta[_dec_metaname(k)] = _dec_metaval(v) | |
793 | ||
794 | def _write_meta(me, f, prefix = ''): | |
795 | """Write the metadata records to F, each with the given PREFIX.""" | |
796 | f.write('\n## Metadata.\n') | |
797 | for k, v in me._meta.iteritems(): | |
798 | f.write('%s%s=%s\n' % (prefix, _enc_metaname(k), _enc_metaval(v))) | |
799 | ||
800 | def _get_meta(me, name, default): | |
801 | return me._meta.get(name, default) | |
802 | def _put_meta(me, name, value): | |
803 | me._mark_dirty() | |
804 | me._meta[name] = value | |
805 | def _del_meta(me, name): | |
806 | me._mark_dirty() | |
807 | del me._meta[name] | |
808 | def _iter_meta(me): | |
809 | return me._meta.iteritems() | |
810 | ||
811 | def _parse_passwd(me, line): | |
812 | """Parse LINE as a password LABEL=PAYLOAD pair, and updates `_pw'.""" | |
813 | k, v = me._eqsplit(line) | |
814 | me._pw[_unb64(k)] = _unb64(v) | |
815 | ||
816 | def _write_passwd(me, f, prefix = ''): | |
817 | """Write the password records to F, each with the given PREFIX.""" | |
818 | f.write('\n## Password data.\n') | |
819 | for k, v in me._pw.iteritems(): | |
820 | f.write('%s%s=%s\n' % (prefix, _b64(k), _b64(v))) | |
821 | ||
822 | def _get_passwd(me, label): | |
823 | return me._pw[str(label)] | |
824 | def _put_passwd(me, label, payload): | |
825 | me._mark_dirty() | |
826 | me._pw[str(label)] = payload | |
827 | def _del_passwd(me, label): | |
828 | me._mark_dirty() | |
829 | del me._pw[str(label)] | |
830 | def _iter_passwds(me): | |
831 | return me._pw.iteritems() | |
832 | ||
833 | class FlatFileStorageBackend (PlainTextBackend): | |
834 | """ | |
835 | I maintain a password database in a plain text file. | |
836 | ||
837 | The text file consists of lines, as follows. | |
838 | ||
839 | * Empty lines, and lines beginning with `#' (in the leftmost column only) | |
840 | are ignored. | |
841 | ||
842 | * Lines of the form `$LABEL=PAYLOAD' store password data. Both LABEL and | |
843 | PAYLOAD are base64-encoded, without `=' padding. | |
844 | ||
845 | * Lines of the form `NAME=VALUE' store metadata. If the NAME contains | |
846 | characters other than alphanumerics, hyphens, underscores, and colons, | |
847 | then it is form-urlencoded, and prefixed wth `!'. If the VALUE | |
848 | contains such characters, then it is base64-encoded, without `=' | |
849 | padding, and prefixed with `?'. | |
850 | ||
851 | * Other lines are erroneous. | |
852 | ||
853 | The file is rewritten from scratch when it's changed: any existing | |
854 | commentary is lost, and items may be reordered. There is no file locking, | |
855 | but the file is updated atomically, by renaming. | |
856 | ||
857 | It is expected that the FlatFileStorageBackend is used mostly for | |
858 | diagnostics and transfer, rather than for a live system. | |
859 | """ | |
860 | ||
861 | NAME = 'flat' | |
862 | PRIO = 0 | |
863 | MAGIC = '### pwsafe password database' | |
864 | ||
865 | def _open(me, file, writep): | |
866 | if not _OS.path.isfile(file): raise StorageBackendRefusal | |
867 | me._parse_file(file, magic = me.MAGIC) | |
868 | def _parse_line(me, line): | |
869 | if line.startswith('$'): me._parse_passwd(line[1:]) | |
870 | else: me._parse_meta(line) | |
871 | ||
872 | def _create(me, file): | |
873 | with me._create_file(file, freshp = True) as f: pass | |
874 | me._file = file | |
875 | me._mark_dirty() | |
876 | ||
877 | def _close(me, abruptp): | |
878 | if not abruptp and me._dirtyp: | |
879 | me._write_file(me._file, me._write_body, magic = me.MAGIC) | |
880 | ||
881 | def _write_body(me, f): | |
882 | me._write_meta(f) | |
883 | me._write_passwd(f, '$') | |
884 | ||
b61e9efe MW |
885 | class DirectoryStorageBackend (PlainTextBackend): |
886 | """ | |
887 | I maintain a password database in a directory, with one file per password. | |
888 | ||
889 | This makes password databases easy to maintain in a revision-control system | |
890 | such as Git. | |
891 | ||
892 | The directory is structured as follows. | |
893 | ||
894 | dir/meta Contains metadata, similar to the `FlatFileBackend'. | |
895 | ||
896 | dir/pw/LABEL Contains the (raw binary) payload for the given password | |
897 | LABEL (base64-encoded, without the useless `=' padding, and | |
898 | with `/' replaced by `.'). | |
899 | ||
900 | dir/tmp/ Contains temporary files used by the implementation. | |
901 | """ | |
902 | ||
903 | NAME = 'dir' | |
904 | METAMAGIC = '### pwsafe password directory metadata' | |
905 | ||
906 | def _open(me, file, writep): | |
907 | if not _OS.path.isdir(file) or \ | |
908 | not _OS.path.isdir(_OS.path.join(file, 'pw')) or \ | |
909 | not _OS.path.isdir(_OS.path.join(file, 'tmp')) or \ | |
910 | not _OS.path.isfile(_OS.path.join(file, 'meta')): | |
911 | raise StorageBackendRefusal | |
912 | me._dir = file | |
913 | me._parse_file(_OS.path.join(file, 'meta'), magic = me.METAMAGIC) | |
914 | def _parse_line(me, line): | |
915 | me._parse_meta(line) | |
916 | ||
917 | def _create(me, file): | |
918 | _OS.mkdir(file, 0700) | |
919 | _OS.mkdir(_OS.path.join(file, 'pw'), 0700) | |
920 | _OS.mkdir(_OS.path.join(file, 'tmp'), 0700) | |
921 | me._mark_dirty() | |
922 | me._dir = file | |
923 | ||
924 | def _close(me, abruptp): | |
925 | if not abruptp and me._dirtyp: | |
926 | me._write_file(_OS.path.join(me._dir, 'meta'), | |
927 | me._write_meta, magic = me.METAMAGIC) | |
928 | ||
929 | def _pwfile(me, label, dir = 'pw'): | |
930 | return _OS.path.join(me._dir, dir, _b64(label).replace('/', '.')) | |
931 | def _get_passwd(me, label): | |
932 | try: | |
933 | f = open(me._pwfile(label), 'rb') | |
f6d012db MW |
934 | except (OSError, IOError): |
935 | if _excval().errno == _E.ENOENT: raise KeyError(label) | |
b61e9efe MW |
936 | else: raise |
937 | with f: return f.read() | |
938 | def _put_passwd(me, label, payload): | |
939 | new = me._pwfile(label, 'tmp') | |
940 | fd = _OS.open(new, _OS.O_WRONLY | _OS.O_CREAT | _OS.O_TRUNC, 0600) | |
941 | _OS.close(fd) | |
942 | with open(new, 'wb') as f: f.write(payload) | |
943 | _OS.rename(new, me._pwfile(label)) | |
944 | def _del_passwd(me, label): | |
945 | try: | |
946 | _OS.remove(me._pwfile(label)) | |
f6d012db MW |
947 | except (OSError, IOError): |
948 | if _excval().errno == _E.ENOENT: raise KeyError(label) | |
b61e9efe MW |
949 | else: raise |
950 | def _iter_passwds(me): | |
951 | pw = _OS.path.join(me._dir, 'pw') | |
952 | for i in _OS.listdir(pw): | |
953 | with open(_OS.path.join(pw, i), 'rb') as f: pld = f.read() | |
954 | yield _unb64(i.replace('.', '/')), pld | |
955 | ||
494b719c | 956 | ###-------------------------------------------------------------------------- |
d1c45f5c | 957 | ### Password storage. |
43c09851 | 958 | |
43c09851 | 959 | class PW (object): |
d1c45f5c MW |
960 | """ |
961 | I represent a secure (ish) password store. | |
962 | ||
963 | I can store short secrets, associated with textual names, in a way which | |
964 | doesn't leak too much information about them. | |
965 | ||
2119e334 | 966 | I implement (some of) the Python mapping protocol. |
d1c45f5c | 967 | |
494b719c MW |
968 | I keep track of everything using a StorageBackend object. This contains |
969 | password entries, identified by cryptographic labels, and a number of | |
970 | metadata items. | |
d1c45f5c MW |
971 | |
972 | cipher Names the Catacomb cipher selected. | |
973 | ||
974 | hash Names the Catacomb hash function selected. | |
975 | ||
976 | key Cipher and MAC keys, each prefixed by a 16-bit big-endian | |
977 | length and concatenated, encrypted using the master | |
978 | passphrase. | |
979 | ||
980 | mac Names the Catacomb message authentication code selected. | |
981 | ||
982 | magic A magic string for obscuring password tag names. | |
983 | ||
984 | salt The salt for hashing the passphrase. | |
985 | ||
986 | tag The master passphrase's tag, for the Pixie's benefit. | |
987 | ||
494b719c MW |
988 | Password entries are assigned labels of the form `$' || H(MAGIC || TAG); |
989 | the corresponding value consists of a pair (TAG, PASSWD), prefixed with | |
990 | 16-bit lengths, concatenated, padded to a multiple of 256 octets, and | |
991 | encrypted using the stored keys. | |
d1c45f5c MW |
992 | """ |
993 | ||
4a35c9a7 | 994 | def __init__(me, file, writep = False): |
d1c45f5c | 995 | """ |
494b719c | 996 | Initialize a PW object from the database in FILE. |
d1c45f5c | 997 | |
494b719c MW |
998 | If WRITEP is false (the default) then the database is opened read-only; |
999 | if true then it may be written. Requests the database password from the | |
1000 | Pixie, which may cause interaction. | |
d1c45f5c MW |
1001 | """ |
1002 | ||
1003 | ## Open the database. | |
6baae405 | 1004 | me.db = StorageBackend.open(file, writep) |
d1c45f5c MW |
1005 | |
1006 | ## Find out what crypto to use. | |
494b719c MW |
1007 | c = _C.gcciphers[me.db.get_meta('cipher')] |
1008 | h = _C.gchashes[me.db.get_meta('hash')] | |
1009 | m = _C.gcmacs[me.db.get_meta('mac')] | |
d1c45f5c MW |
1010 | |
1011 | ## Request the passphrase and extract the master keys. | |
494b719c MW |
1012 | tag = me.db.get_meta('tag') |
1013 | ppk = PPK(_C.ppread(tag), c, h, m, me.db.get_meta('salt')) | |
43c09851 | 1014 | try: |
494b719c | 1015 | b = _C.ReadBuffer(ppk.decrypt(me.db.get_meta('key'))) |
43c09851 | 1016 | except DecryptError: |
1017 | _C.ppcancel(tag) | |
1018 | raise | |
9a7b948f MW |
1019 | me.ck = b.getblk16() |
1020 | me.mk = b.getblk16() | |
1c7419c9 | 1021 | if not b.endp: raise ValueError('trailing junk') |
d1c45f5c MW |
1022 | |
1023 | ## Set the key, and stash it and the tag-hashing secret. | |
43c09851 | 1024 | me.k = Crypto(c, h, m, me.ck, me.mk) |
494b719c | 1025 | me.magic = me.k.decrypt(me.db.get_meta('magic')) |
d1c45f5c | 1026 | |
09b8041d | 1027 | @classmethod |
6baae405 | 1028 | def create(cls, dbcls, file, tag, c, h, m): |
09b8041d | 1029 | """ |
6baae405 | 1030 | Create and initialize a new database FILE using StorageBackend DBCLS. |
09b8041d MW |
1031 | |
1032 | We want a GCipher subclass C, a GHash subclass H, and a GMAC subclass M; | |
1033 | and a Pixie passphrase TAG. | |
1034 | ||
1035 | This doesn't return a working object: it just creates the database file | |
1036 | and gets out of the way. | |
1037 | """ | |
1038 | ||
1039 | ## Set up the cryptography. | |
1040 | pp = _C.ppread(tag, _C.PMODE_VERIFY) | |
1041 | ppk = PPK(pp, c, h, m) | |
1042 | ck = _C.rand.block(c.keysz.default) | |
1043 | mk = _C.rand.block(c.keysz.default) | |
1044 | k = Crypto(c, h, m, ck, mk) | |
1045 | ||
1046 | ## Set up and initialize the database. | |
494b719c | 1047 | kct = ppk.encrypt(_C.WriteBuffer().putblk16(ck).putblk16(mk)) |
6baae405 | 1048 | with dbcls.create(file) as db: |
494b719c MW |
1049 | db.put_meta('tag', tag) |
1050 | db.put_meta('salt', ppk.salt) | |
1051 | db.put_meta('cipher', c.name) | |
1052 | db.put_meta('hash', h.name) | |
1053 | db.put_meta('mac', m.name) | |
1054 | db.put_meta('key', kct) | |
1055 | db.put_meta('magic', k.encrypt(_C.rand.block(h.hashsz))) | |
09b8041d | 1056 | |
43c09851 | 1057 | def keyxform(me, key): |
494b719c MW |
1058 | """Transform the KEY (actually a password tag) into a password label.""" |
1059 | return me.k.h().hash(me.magic).hash(key).done() | |
d1c45f5c | 1060 | |
43c09851 | 1061 | def changepp(me): |
d1c45f5c MW |
1062 | """ |
1063 | Change the database password. | |
1064 | ||
1065 | Requests the new password from the Pixie, which will probably cause | |
1066 | interaction. | |
1067 | """ | |
494b719c | 1068 | tag = me.db.get_meta('tag') |
43c09851 | 1069 | _C.ppcancel(tag) |
1070 | ppk = PPK(_C.ppread(tag, _C.PMODE_VERIFY), | |
d1c45f5c | 1071 | me.k.c.__class__, me.k.h, me.k.m.__class__) |
494b719c MW |
1072 | kct = ppk.encrypt(_C.WriteBuffer().putblk16(me.ck).putblk16(me.mk)) |
1073 | me.db.put_meta('key', kct) | |
1074 | me.db.put_meta('salt', ppk.salt) | |
d1c45f5c | 1075 | |
43c09851 | 1076 | def pack(me, key, value): |
494b719c | 1077 | """Pack the KEY and VALUE into a ciphertext, and return it.""" |
9a7b948f MW |
1078 | b = _C.WriteBuffer() |
1079 | b.putblk16(key).putblk16(value) | |
1080 | b.zero(((b.size + 255) & ~255) - b.size) | |
1081 | return me.k.encrypt(b) | |
d1c45f5c MW |
1082 | |
1083 | def unpack(me, ct): | |
1084 | """ | |
1085 | Unpack a ciphertext CT and return a (KEY, VALUE) pair. | |
1086 | ||
1087 | Might raise DecryptError, of course. | |
1088 | """ | |
9a7b948f MW |
1089 | b = _C.ReadBuffer(me.k.decrypt(ct)) |
1090 | key = b.getblk16() | |
1091 | value = b.getblk16() | |
43c09851 | 1092 | return key, value |
d1c45f5c MW |
1093 | |
1094 | ## Mapping protocol. | |
1095 | ||
43c09851 | 1096 | def __getitem__(me, key): |
494b719c MW |
1097 | """Return the password for the given KEY.""" |
1098 | try: return me.unpack(me.db.get_passwd(me.keyxform(key)))[1] | |
1c7419c9 | 1099 | except KeyError: raise KeyError(key) |
d1c45f5c | 1100 | |
43c09851 | 1101 | def __setitem__(me, key, value): |
494b719c MW |
1102 | """Associate the password VALUE with the KEY.""" |
1103 | me.db.put_passwd(me.keyxform(key), me.pack(key, value)) | |
d1c45f5c | 1104 | |
43c09851 | 1105 | def __delitem__(me, key): |
494b719c MW |
1106 | """Forget all about the KEY.""" |
1107 | try: me.db.del_passwd(me.keyxform(key)) | |
1c7419c9 | 1108 | except KeyError: raise KeyError(key) |
d1c45f5c | 1109 | |
43c09851 | 1110 | def __iter__(me): |
494b719c MW |
1111 | """Iterate over the known password tags.""" |
1112 | for _, pld in me.db.iter_passwds(): | |
1113 | yield me.unpack(pld)[0] | |
43c09851 | 1114 | |
5bf6e9f5 MW |
1115 | ## Context protocol. |
1116 | ||
1117 | def __enter__(me): | |
1118 | return me | |
1119 | def __exit__(me, excty, excval, exctb): | |
053c2659 | 1120 | me.db.close(excval is not None) |
5bf6e9f5 | 1121 | |
d1c45f5c | 1122 | ###----- That's all, folks -------------------------------------------------- |