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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 | ###-------------------------------------------------------------------------- | |
a41fd652 MW |
38 | ### Python version portability. |
39 | ||
82910fd3 MW |
40 | def _iterkeys(dict): return dict.iterkeys() |
41 | def _itervalues(dict): return dict.itervalues() | |
42 | def _iteritems(dict): return dict.iteritems() | |
43 | ||
2aa7d3a9 MW |
44 | def _bin(text): return text |
45 | def _text(bin): return bin | |
46 | ||
47 | _NUL = _bin('\0') | |
48 | _CIPHER = _bin('cipher:') | |
49 | _MAC = _bin('mac:') | |
50 | ||
a41fd652 MW |
51 | def _excval(): return SYS.exc_info()[1] |
52 | ||
53 | ###-------------------------------------------------------------------------- | |
af861fb7 MW |
54 | ### Text encoding utilities. |
55 | ||
56 | def _literalp(s): | |
57 | """ | |
58 | Answer whether S can be represented literally. | |
59 | ||
60 | If True, then S can be stored literally, as a metadata item name or | |
61 | value; if False, then S requires some kind of encoding. | |
62 | """ | |
63 | return all(ch.isalnum() or ch in '-_:' for ch in s) | |
64 | ||
65 | def _enc_metaname(name): | |
66 | """Encode NAME as a metadata item name, returning the result.""" | |
67 | if _literalp(name): | |
68 | return name | |
69 | else: | |
70 | sio = _StringIO() | |
71 | sio.write('!') | |
72 | for ch in name: | |
73 | if _literalp(ch): sio.write(ch) | |
74 | elif ch == ' ': sio.write('+') | |
75 | else: sio.write('%%%02x' % ord(ch)) | |
76 | return sio.getvalue() | |
77 | ||
78 | def _dec_metaname(name): | |
79 | """Decode NAME as a metadata item name, returning the result.""" | |
80 | if not name.startswith('!'): | |
81 | return name | |
82 | else: | |
83 | sio = _StringIO() | |
84 | i, n = 1, len(name) | |
85 | while i < n: | |
86 | ch = name[i] | |
87 | i += 1 | |
88 | if ch == '+': | |
89 | sio.write(' ') | |
90 | elif ch == '%': | |
91 | sio.write(chr(int(name[i:i + 2], 16))) | |
92 | i += 2 | |
93 | else: | |
94 | sio.write(ch) | |
95 | return sio.getvalue() | |
96 | ||
97 | def _b64(s): | |
98 | """Encode S as base64, without newlines, and trimming `=' padding.""" | |
3e80d327 | 99 | return s.encode('base64').replace('\n', '').rstrip('=') |
af861fb7 MW |
100 | def _unb64(s): |
101 | """Decode S as base64 with trimmed `=' padding.""" | |
102 | return (s + '='*((4 - len(s))%4)).decode('base64') | |
103 | ||
104 | def _enc_metaval(val): | |
105 | """Encode VAL as a metadata item value, returning the result.""" | |
106 | if _literalp(val): return val | |
107 | else: return '?' + _b64(val) | |
108 | ||
109 | def _dec_metaval(val): | |
110 | """Decode VAL as a metadata item value, returning the result.""" | |
111 | if not val.startswith('?'): return val | |
112 | else: return _unb64(val[1:]) | |
113 | ||
114 | ###-------------------------------------------------------------------------- | |
d1c45f5c MW |
115 | ### Underlying cryptography. |
116 | ||
43c09851 | 117 | class DecryptError (Exception): |
d1c45f5c MW |
118 | """ |
119 | I represent a failure to decrypt a message. | |
120 | ||
121 | Usually this means that someone used the wrong key, though it can also | |
122 | mean that a ciphertext has been modified. | |
123 | """ | |
43c09851 | 124 | pass |
125 | ||
126 | class Crypto (object): | |
d1c45f5c MW |
127 | """ |
128 | I represent a symmetric crypto transform. | |
129 | ||
130 | There's currently only one transform implemented, which is the obvious | |
131 | generic-composition construction: given a message m, and keys K0 and K1, we | |
132 | choose an IV v, and compute: | |
133 | ||
134 | * y = v || E(K0, v; m) | |
135 | * t = M(K1; y) | |
136 | ||
137 | The final ciphertext is t || y. | |
138 | """ | |
139 | ||
43c09851 | 140 | def __init__(me, c, h, m, ck, mk): |
d1c45f5c MW |
141 | """ |
142 | Initialize the Crypto object with a given algorithm selection and keys. | |
143 | ||
144 | We need a GCipher subclass C, a GHash subclass H, a GMAC subclass M, and | |
145 | keys CK and MK for C and M respectively. | |
146 | """ | |
43c09851 | 147 | me.c = c(ck) |
148 | me.m = m(mk) | |
149 | me.h = h | |
d1c45f5c | 150 | |
43c09851 | 151 | def encrypt(me, pt): |
d1c45f5c MW |
152 | """ |
153 | Encrypt the message PT and return the resulting ciphertext. | |
154 | """ | |
9a7b948f MW |
155 | blksz = me.c.__class__.blksz |
156 | b = _C.WriteBuffer() | |
157 | if blksz: | |
158 | iv = _C.rand.block(blksz) | |
43c09851 | 159 | me.c.setiv(iv) |
9a7b948f MW |
160 | b.put(iv) |
161 | b.put(me.c.encrypt(pt)) | |
162 | t = me.m().hash(b).done() | |
163 | return t + str(buffer(b)) | |
164 | ||
43c09851 | 165 | def decrypt(me, ct): |
d1c45f5c MW |
166 | """ |
167 | Decrypt the ciphertext CT, returning the plaintext. | |
168 | ||
169 | Raises DecryptError if anything goes wrong. | |
170 | """ | |
9a7b948f MW |
171 | blksz = me.c.__class__.blksz |
172 | tagsz = me.m.__class__.tagsz | |
173 | b = _C.ReadBuffer(ct) | |
174 | t = b.get(tagsz) | |
175 | h = me.m() | |
176 | if blksz: | |
177 | iv = b.get(blksz) | |
178 | me.c.setiv(iv) | |
179 | h.hash(iv) | |
180 | x = b.get(b.left) | |
181 | h.hash(x) | |
182 | if t != h.done(): raise DecryptError | |
183 | return me.c.decrypt(x) | |
b2687a0a | 184 | |
43c09851 | 185 | class PPK (Crypto): |
d1c45f5c MW |
186 | """ |
187 | I represent a crypto transform whose keys are derived from a passphrase. | |
188 | ||
189 | The password is salted and hashed; the salt is available as the `salt' | |
190 | attribute. | |
191 | """ | |
192 | ||
43c09851 | 193 | def __init__(me, pp, c, h, m, salt = None): |
d1c45f5c MW |
194 | """ |
195 | Initialize the PPK object with a passphrase and algorithm selection. | |
196 | ||
197 | We want a passphrase PP, a GCipher subclass C, a GHash subclass H, a GMAC | |
198 | subclass M, and a SALT. The SALT may be None, if we're generating new | |
199 | keys, indicating that a salt should be chosen randomly. | |
200 | """ | |
43c09851 | 201 | if not salt: salt = _C.rand.block(h.hashsz) |
2aa7d3a9 | 202 | tag = pp + _NUL + salt |
43c09851 | 203 | Crypto.__init__(me, c, h, m, |
2aa7d3a9 MW |
204 | h().hash(_CIPHER).hash(tag).done(), |
205 | h().hash(_MAC).hash(tag).done()) | |
43c09851 | 206 | me.salt = salt |
207 | ||
d1c45f5c | 208 | ###-------------------------------------------------------------------------- |
494b719c MW |
209 | ### Backend storage. |
210 | ||
6baae405 MW |
211 | class StorageBackendRefusal (Exception): |
212 | """ | |
213 | I signify that a StorageBackend subclass has refused to open a file. | |
214 | ||
215 | This is used by the StorageBackend.open class method. | |
216 | """ | |
217 | pass | |
218 | ||
219 | class StorageBackendClass (type): | |
220 | """ | |
221 | I am a metaclass for StorageBackend classes. | |
222 | ||
223 | My main feature is that I register my concrete instances (with a `NAME' | |
224 | which is not `None') with the StorageBackend class. | |
225 | """ | |
226 | def __init__(me, name, supers, dict): | |
227 | """ | |
228 | Register a new concrete StorageBackend subclass. | |
229 | """ | |
230 | super(StorageBackendClass, me).__init__(name, supers, dict) | |
231 | if me.NAME is not None: StorageBackend.register_concrete_subclass(me) | |
232 | ||
494b719c MW |
233 | class StorageBackend (object): |
234 | """ | |
1726ab40 MW |
235 | I provide basic protocol for password storage backends. |
236 | ||
237 | I'm an abstract class: you want one of my subclasses if you actually want | |
6baae405 MW |
238 | to do something useful. But I maintain a list of my subclasses and can |
239 | choose an appropriate one to open a database file you've found lying about. | |
494b719c MW |
240 | |
241 | Backends are responsible for storing and retrieving stuff, but not for the | |
242 | cryptographic details. Backends need to store two kinds of information: | |
243 | ||
244 | * metadata, consisting of a number of property names and their values; | |
245 | and | |
246 | ||
247 | * password mappings, consisting of a number of binary labels and | |
248 | payloads. | |
1726ab40 MW |
249 | |
250 | Backends need to implement the following ordinary methods. See the calling | |
251 | methods for details of the subclass responsibilities. | |
252 | ||
253 | BE._create(FILE) Create a new database in FILE; used by `create'. | |
254 | ||
255 | BE._open(FILE, WRITEP) | |
256 | Open the existing database FILE; used by `open'. | |
257 | ||
053c2659 MW |
258 | BE._close(ABRUPTP) Close the database, freeing up any resources. If |
259 | ABRUPTP then don't try to commit changes. | |
1726ab40 MW |
260 | |
261 | BE._get_meta(NAME, DEFAULT) | |
262 | Return the value of the metadata item with the given | |
263 | NAME, or DEFAULT if it doesn't exist; used by | |
264 | `get_meta'. | |
265 | ||
266 | BE._put_meta(NAME, VALUE) | |
267 | Set the VALUE of the metadata item with the given | |
268 | NAME, creating one if necessary; used by `put_meta'. | |
269 | ||
270 | BE._del_meta(NAME) Forget the metadata item with the given NAME; raise | |
271 | `KeyError' if there is no such item; used by | |
272 | `del_meta'. | |
273 | ||
274 | BE._iter_meta() Return an iterator over the metadata (NAME, VALUE) | |
275 | pairs; used by `iter_meta'. | |
276 | ||
277 | BE._get_passwd(LABEL) | |
278 | Return the password payload stored with the (binary) | |
279 | LABEL; used by `get_passwd'. | |
280 | ||
281 | BE._put_passwd(LABEL, PAYLOAD) | |
282 | Associate the (binary) PAYLOAD with the LABEL, | |
283 | forgetting any previous payload for that LABEL; used | |
284 | by `put_passwd'. | |
285 | ||
286 | BE._del_passwd(LABEL) Forget the password record with the given LABEL; used | |
287 | by `_del_passwd'. | |
288 | ||
289 | BE._iter_passwds() Return an iterator over the password (LABEL, PAYLOAD) | |
290 | pairs; used by `iter_passwds'. | |
6baae405 MW |
291 | |
292 | Also, concrete subclasses should define the following class attributes. | |
293 | ||
294 | NAME The name of the backend, so that the user can select | |
295 | it when creating a new database. | |
296 | ||
297 | PRIO An integer priority: backends are tried in decreasing | |
298 | priority order when opening an existing database. | |
494b719c MW |
299 | """ |
300 | ||
6baae405 MW |
301 | __metaclass__ = StorageBackendClass |
302 | NAME = None | |
303 | PRIO = 10 | |
304 | ||
305 | ## The registry of subclasses. | |
306 | CLASSES = {} | |
307 | ||
494b719c MW |
308 | FAIL = ['FAIL'] |
309 | ||
6baae405 MW |
310 | @staticmethod |
311 | def register_concrete_subclass(sub): | |
312 | """Register a concrete subclass, so that `open' can try it.""" | |
313 | StorageBackend.CLASSES[sub.NAME] = sub | |
314 | ||
315 | @staticmethod | |
316 | def byname(name): | |
317 | """ | |
318 | Return the concrete subclass with the given NAME. | |
319 | ||
320 | Raise `KeyError' if the name isn't found. | |
321 | """ | |
322 | return StorageBackend.CLASSES[name] | |
323 | ||
324 | @staticmethod | |
325 | def classes(): | |
326 | """Return an iterator over the concrete subclasses.""" | |
82910fd3 | 327 | return _itervalues(StorageBackend.CLASSES) |
6baae405 MW |
328 | |
329 | @staticmethod | |
330 | def open(file, writep = False): | |
331 | """Open a database FILE, using some appropriate backend.""" | |
332 | _OS.stat(file) | |
333 | for cls in sorted(StorageBackend.CLASSES.values(), reverse = True, | |
334 | key = lambda cls: cls.PRIO): | |
335 | try: return cls(file, writep) | |
336 | except StorageBackendRefusal: pass | |
337 | raise StorageBackendRefusal | |
494b719c MW |
338 | |
339 | @classmethod | |
340 | def create(cls, file): | |
1726ab40 MW |
341 | """ |
342 | Create a new database in the named FILE, using this backend. | |
343 | ||
344 | Subclasses must implement the `_create' instance method. | |
345 | """ | |
494b719c | 346 | return cls(writep = True, _magic = lambda me: me._create(file)) |
494b719c MW |
347 | |
348 | def __init__(me, file = None, writep = False, _magic = None, *args, **kw): | |
349 | """ | |
350 | Main constructor. | |
1726ab40 MW |
351 | |
352 | Subclasses are not, in general, expected to override this: there's a | |
353 | somewhat hairy protocol between the constructor and some of the class | |
354 | methods. Instead, the main hook for customization is the subclass's | |
355 | `_open' method, which is invoked in the usual case. | |
494b719c MW |
356 | """ |
357 | super(StorageBackend, me).__init__(*args, **kw) | |
e3b6c0d3 | 358 | if me.NAME is None: raise ValueError('abstract class') |
494b719c | 359 | if _magic is not None: _magic(me) |
e3b6c0d3 | 360 | elif file is None: raise ValueError('missing file parameter') |
1726ab40 | 361 | else: me._open(file, writep) |
494b719c MW |
362 | me._writep = writep |
363 | me._livep = True | |
364 | ||
053c2659 | 365 | def close(me, abruptp = False): |
494b719c MW |
366 | """ |
367 | Close the database. | |
368 | ||
369 | It is harmless to attempt to close a database which has been closed | |
1726ab40 | 370 | already. Calls the subclass's `_close' method. |
494b719c MW |
371 | """ |
372 | if me._livep: | |
373 | me._livep = False | |
053c2659 | 374 | me._close(abruptp) |
494b719c MW |
375 | |
376 | ## Utilities. | |
377 | ||
378 | def _check_live(me): | |
379 | """Raise an error if the receiver has been closed.""" | |
e3b6c0d3 | 380 | if not me._livep: raise ValueError('database is closed') |
494b719c MW |
381 | |
382 | def _check_write(me): | |
383 | """Raise an error if the receiver is not open for writing.""" | |
384 | me._check_live() | |
e3b6c0d3 | 385 | if not me._writep: raise ValueError('database is read-only') |
494b719c MW |
386 | |
387 | def _check_meta_name(me, name): | |
388 | """ | |
389 | Raise an error unless NAME is a valid name for a metadata item. | |
390 | ||
391 | Metadata names may not start with `$': such names are reserved for | |
392 | password storage. | |
393 | """ | |
394 | if name.startswith('$'): | |
e3b6c0d3 | 395 | raise ValueError("invalid metadata key `%s'" % name) |
494b719c MW |
396 | |
397 | ## Context protocol. | |
398 | ||
399 | def __enter__(me): | |
400 | """Context protocol: make sure the database is closed on exit.""" | |
401 | return me | |
402 | def __exit__(me, exctype, excvalue, exctb): | |
403 | """Context protocol: see `__enter__'.""" | |
053c2659 | 404 | me.close(excvalue is not None) |
494b719c MW |
405 | |
406 | ## Metadata. | |
407 | ||
408 | def get_meta(me, name, default = FAIL): | |
409 | """ | |
410 | Fetch the value for the metadata item NAME. | |
411 | ||
412 | If no such item exists, then return DEFAULT if that was set; otherwise | |
413 | raise a `KeyError'. | |
1726ab40 MW |
414 | |
415 | This calls the subclass's `_get_meta' method, which should return the | |
416 | requested item or return the given DEFAULT value. It may assume that the | |
417 | name is valid and the database is open. | |
494b719c MW |
418 | """ |
419 | me._check_meta_name(name) | |
420 | me._check_live() | |
1726ab40 | 421 | value = me._get_meta(name, default) |
e3b6c0d3 | 422 | if value is StorageBackend.FAIL: raise KeyError(name) |
494b719c MW |
423 | return value |
424 | ||
425 | def put_meta(me, name, value): | |
1726ab40 MW |
426 | """ |
427 | Store VALUE in the metadata item called NAME. | |
428 | ||
429 | This calls the subclass's `_put_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._put_meta(name, value) |
494b719c MW |
435 | |
436 | def del_meta(me, name): | |
1726ab40 MW |
437 | """ |
438 | Forget about the metadata item with the given NAME. | |
439 | ||
440 | This calls the subclass's `_del_meta' method, which may assume that the | |
441 | name is valid and the database is open for writing. | |
442 | """ | |
494b719c MW |
443 | me._check_meta_name(name) |
444 | me._check_write() | |
1726ab40 | 445 | me._del_meta(name) |
494b719c MW |
446 | |
447 | def iter_meta(me): | |
1726ab40 MW |
448 | """ |
449 | Return an iterator over the name/value metadata items. | |
494b719c | 450 | |
1726ab40 MW |
451 | This calls the subclass's `_iter_meta' method, which may assume that the |
452 | database is open. | |
453 | """ | |
454 | me._check_live() | |
455 | return me._iter_meta() | |
494b719c MW |
456 | |
457 | def get_passwd(me, label): | |
458 | """ | |
459 | Fetch and return the payload stored with the (opaque, binary) LABEL. | |
460 | ||
461 | If there is no such payload then raise `KeyError'. | |
1726ab40 MW |
462 | |
463 | This calls the subclass's `_get_passwd' method, which may assume that the | |
464 | database is open. | |
494b719c MW |
465 | """ |
466 | me._check_live() | |
1726ab40 | 467 | return me._get_passwd(label) |
494b719c MW |
468 | |
469 | def put_passwd(me, label, payload): | |
470 | """ | |
471 | Associate the (opaque, binary) PAYLOAD with the (opaque, binary) LABEL. | |
472 | ||
473 | Any previous payload for LABEL is forgotten. | |
1726ab40 MW |
474 | |
475 | This calls the subclass's `_put_passwd' method, which may assume that the | |
476 | database is open for writing. | |
494b719c MW |
477 | """ |
478 | me._check_write() | |
1726ab40 | 479 | me._put_passwd(label, payload) |
494b719c MW |
480 | |
481 | def del_passwd(me, label): | |
482 | """ | |
483 | Forget any PAYLOAD associated with the (opaque, binary) LABEL. | |
484 | ||
485 | If there is no such payload then raise `KeyError'. | |
1726ab40 MW |
486 | |
487 | This calls the subclass's `_del_passwd' method, which may assume that the | |
488 | database is open for writing. | |
494b719c MW |
489 | """ |
490 | me._check_write() | |
1d93191e | 491 | me._del_passwd(label) |
494b719c MW |
492 | |
493 | def iter_passwds(me): | |
1726ab40 MW |
494 | """ |
495 | Return an iterator over the stored password label/payload pairs. | |
496 | ||
497 | This calls the subclass's `_iter_passwds' method, which may assume that | |
498 | the database is open. | |
499 | """ | |
494b719c | 500 | me._check_live() |
1726ab40 MW |
501 | return me._iter_passwds() |
502 | ||
8501dc39 MW |
503 | try: import gdbm as _G |
504 | except ImportError: pass | |
505 | else: | |
506 | class GDBMStorageBackend (StorageBackend): | |
507 | """ | |
508 | My instances store password data in a GDBM database. | |
1726ab40 | 509 | |
8501dc39 MW |
510 | Metadata and password entries are mixed into the same database. The key |
511 | for a metadata item is simply its name; the key for a password entry is | |
512 | the entry's label prefixed by `$', since we're guaranteed that no | |
513 | metadata item name begins with `$'. | |
514 | """ | |
1726ab40 | 515 | |
8501dc39 | 516 | NAME = 'gdbm' |
6baae405 | 517 | |
8501dc39 MW |
518 | def _open(me, file, writep): |
519 | try: me._db = _G.open(file, writep and 'w' or 'r') | |
a41fd652 | 520 | except _G.error: raise StorageBackendRefusal(_excval()) |
1726ab40 | 521 | |
8501dc39 MW |
522 | def _create(me, file): |
523 | me._db = _G.open(file, 'n', 0600) | |
1726ab40 | 524 | |
8501dc39 MW |
525 | def _close(me, abruptp): |
526 | me._db.close() | |
527 | me._db = None | |
1726ab40 | 528 | |
8501dc39 MW |
529 | def _get_meta(me, name, default): |
530 | try: return me._db[name] | |
531 | except KeyError: return default | |
1726ab40 | 532 | |
8501dc39 MW |
533 | def _put_meta(me, name, value): |
534 | me._db[name] = value | |
1726ab40 | 535 | |
8501dc39 MW |
536 | def _del_meta(me, name): |
537 | del me._db[name] | |
1726ab40 | 538 | |
8501dc39 MW |
539 | def _iter_meta(me): |
540 | k = me._db.firstkey() | |
541 | while k is not None: | |
542 | if not k.startswith('$'): yield k, me._db[k] | |
543 | k = me._db.nextkey(k) | |
1726ab40 | 544 | |
8501dc39 MW |
545 | def _get_passwd(me, label): |
546 | return me._db['$' + label] | |
1726ab40 | 547 | |
8501dc39 MW |
548 | def _put_passwd(me, label, payload): |
549 | me._db['$' + label] = payload | |
1726ab40 | 550 | |
8501dc39 MW |
551 | def _del_passwd(me, label): |
552 | del me._db['$' + label] | |
1726ab40 | 553 | |
8501dc39 MW |
554 | def _iter_passwds(me): |
555 | k = me._db.firstkey() | |
556 | while k is not None: | |
557 | if k.startswith('$'): yield k[1:], me._db[k] | |
558 | k = me._db.nextkey(k) | |
494b719c | 559 | |
e92f9aa2 MW |
560 | try: import sqlite3 as _Q |
561 | except ImportError: pass | |
562 | else: | |
563 | class SQLiteStorageBackend (StorageBackend): | |
564 | """ | |
565 | I represent a password database stored in SQLite. | |
566 | ||
567 | Metadata and password items are stored in separate tables, so there's no | |
568 | conflict. Some additional metadata is stored in the `meta' table, with | |
569 | names beginning with `$' so as not to conflict with clients: | |
570 | ||
571 | $version The schema version of the table. | |
572 | """ | |
573 | ||
574 | NAME = 'sqlite' | |
575 | VERSION = 0 | |
576 | ||
577 | def _open(me, file, writep): | |
578 | try: | |
579 | me._db = _Q.connect(file) | |
580 | ver = me._query_scalar( | |
581 | "SELECT value FROM meta WHERE name = '$version'", | |
582 | "version check") | |
a41fd652 MW |
583 | except (_Q.DatabaseError, _Q.OperationalError): |
584 | raise StorageBackendRefusal(_excval()) | |
e3b6c0d3 | 585 | if ver is None: raise ValueError('database broken (missing $version)') |
e92f9aa2 | 586 | elif ver < me.VERSION: me._upgrade(ver) |
e3b6c0d3 MW |
587 | elif ver > me.VERSION: raise ValueError \ |
588 | ('unknown database schema version (%d > %d)' % (ver, me.VERSION)) | |
e92f9aa2 MW |
589 | |
590 | def _create(me, file): | |
591 | fd = _OS.open(file, _OS.O_WRONLY | _OS.O_CREAT | _OS.O_EXCL, 0600) | |
592 | _OS.close(fd) | |
593 | try: | |
594 | me._db = _Q.connect(file) | |
595 | c = me._db.cursor() | |
596 | c.execute(""" | |
597 | CREATE TABLE meta ( | |
598 | name TEXT PRIMARY KEY NOT NULL, | |
599 | value BLOB NOT NULL); | |
600 | """) | |
601 | c.execute(""" | |
602 | CREATE TABLE passwd ( | |
603 | label BLOB PRIMARY KEY NOT NULL, | |
604 | payload BLOB NOT NULL); | |
605 | """) | |
606 | c.execute(""" | |
607 | INSERT INTO meta (name, value) VALUES ('$version', ?); | |
608 | """, [me.VERSION]) | |
609 | except: | |
610 | try: _OS.unlink(file) | |
611 | except OSError: pass | |
612 | raise | |
613 | ||
614 | def _upgrade(me, ver): | |
615 | """Upgrade the database from schema version VER.""" | |
616 | assert False, 'how embarrassing' | |
617 | ||
618 | def _close(me, abruptp): | |
619 | if not abruptp: me._db.commit() | |
620 | me._db.close() | |
621 | me._db = None | |
622 | ||
623 | def _fetch_scalar(me, c, what, default = None): | |
624 | try: row = next(c) | |
625 | except StopIteration: val = default | |
626 | else: val, = row | |
627 | try: row = next(c) | |
628 | except StopIteration: pass | |
e3b6c0d3 | 629 | else: raise ValueError('multiple matching records for %s' % what) |
e92f9aa2 MW |
630 | return val |
631 | ||
632 | def _query_scalar(me, query, what, default = None, args = []): | |
633 | c = me._db.cursor() | |
634 | c.execute(query, args) | |
635 | return me._fetch_scalar(c, what, default) | |
636 | ||
637 | def _get_meta(me, name, default): | |
638 | v = me._query_scalar("SELECT value FROM meta WHERE name = ?", | |
639 | "metadata item `%s'" % name, | |
640 | default = default, args = [name]) | |
641 | if v is default: return v | |
642 | else: return str(v) | |
643 | ||
644 | def _put_meta(me, name, value): | |
645 | c = me._db.cursor() | |
646 | c.execute("INSERT OR REPLACE INTO meta (name, value) VALUES (?, ?)", | |
647 | [name, buffer(value)]) | |
648 | ||
649 | def _del_meta(me, name): | |
650 | c = me._db.cursor() | |
651 | c.execute("DELETE FROM meta WHERE name = ?", [name]) | |
e3b6c0d3 | 652 | if not c.rowcount: raise KeyError(name) |
e92f9aa2 MW |
653 | |
654 | def _iter_meta(me): | |
655 | c = me._db.cursor() | |
656 | c.execute("SELECT name, value FROM meta WHERE name NOT LIKE '$%'") | |
657 | for k, v in c: yield k, str(v) | |
658 | ||
659 | def _get_passwd(me, label): | |
660 | pld = me._query_scalar("SELECT payload FROM passwd WHERE label = ?", | |
661 | "password", default = None, | |
662 | args = [buffer(label)]) | |
e3b6c0d3 | 663 | if pld is None: raise KeyError(label) |
e92f9aa2 MW |
664 | return str(pld) |
665 | ||
666 | def _put_passwd(me, label, payload): | |
667 | c = me._db.cursor() | |
668 | c.execute("INSERT OR REPLACE INTO passwd (label, payload) " | |
669 | "VALUES (?, ?)", | |
670 | [buffer(label), buffer(payload)]) | |
671 | ||
672 | def _del_passwd(me, label): | |
673 | c = me._db.cursor() | |
674 | c.execute("DELETE FROM passwd WHERE label = ?", [label]) | |
e3b6c0d3 | 675 | if not c.rowcount: raise KeyError(label) |
e92f9aa2 MW |
676 | |
677 | def _iter_passwds(me): | |
678 | c = me._db.cursor() | |
679 | c.execute("SELECT label, payload FROM passwd") | |
680 | for k, v in c: yield str(k), str(v) | |
681 | ||
af861fb7 MW |
682 | class PlainTextBackend (StorageBackend): |
683 | """ | |
684 | I'm a utility base class for storage backends which use plain text files. | |
685 | ||
686 | I provide subclasses with the following capabilities. | |
687 | ||
688 | * Creating files, with given modes, optionally ensuring that the file | |
689 | doesn't exist already. | |
690 | ||
691 | * Parsing flat text files, checking leading magic, skipping comments, and | |
692 | providing standard encodings of troublesome characters and binary | |
693 | strings in metadata and password records. See below. | |
694 | ||
695 | * Maintenance of metadata and password records in in-memory dictionaries, | |
696 | with ready implementations of the necessary StorageBackend subclass | |
697 | responsibility methods. (Subclasses can override these if they want to | |
698 | make different arrangements.) | |
699 | ||
700 | Metadata records are written with an optional prefix string chosen by the | |
701 | caller, followed by a `NAME=VALUE' pair. The NAME is form-urlencoded and | |
702 | prefixed with `!' if it contains strange characters; the VALUE is base64- | |
703 | encoded (without the pointless trailing `=' padding) and prefixed with `?' | |
704 | if necessary. | |
705 | ||
706 | Password records are written with an optional prefix string chosen by the | |
707 | caller, followed by a LABEL=PAYLOAD pair, both of which are base64-encoded | |
708 | (without padding). | |
709 | ||
710 | The following attributes are available for subclasses: | |
711 | ||
712 | _meta Dictionary mapping metadata item names to their values. | |
713 | Populated by `_parse_meta' and managed by `_get_meta' and | |
714 | friends. | |
715 | ||
716 | _pw Dictionary mapping password labels to encrypted payloads. | |
717 | Populated by `_parse_passwd' and managed by `_get_passwd' and | |
718 | friends. | |
719 | ||
720 | _dirtyp Boolean: set if either of the dictionaries has been modified. | |
721 | """ | |
722 | ||
723 | def __init__(me, *args, **kw): | |
724 | """ | |
725 | Hook for initialization. | |
726 | ||
727 | Sets up the published instance attributes. | |
728 | """ | |
729 | me._meta = {} | |
730 | me._pw = {} | |
731 | me._dirtyp = False | |
732 | super(PlainTextBackend, me).__init__(*args, **kw) | |
733 | ||
734 | def _create_file(me, file, mode = 0600, freshp = False): | |
735 | """ | |
736 | Make sure FILE exists, creating it with the given MODE if necessary. | |
737 | ||
738 | If FRESHP is true, then make sure the file did not exist previously. | |
739 | Return a file object for the newly created file. | |
740 | """ | |
741 | flags = _OS.O_CREAT | _OS.O_WRONLY | |
742 | if freshp: flags |= _OS.O_EXCL | |
743 | else: flags |= _OS.O_TRUNC | |
744 | fd = _OS.open(file, flags, mode) | |
745 | return _OS.fdopen(fd, 'w') | |
746 | ||
747 | def _mark_dirty(me): | |
748 | """ | |
749 | Set the `_dirtyp' flag. | |
750 | ||
751 | Subclasses might find it useful to intercept this method. | |
752 | """ | |
753 | me._dirtyp = True | |
754 | ||
755 | def _eqsplit(me, line): | |
756 | """ | |
757 | Extract the KEY, VALUE pair from a LINE of the form `KEY=VALUE'. | |
758 | ||
759 | Raise `ValueError' if there is no `=' in the LINE. | |
760 | """ | |
761 | eq = line.index('=') | |
762 | return line[:eq], line[eq + 1:] | |
763 | ||
764 | def _parse_file(me, file, magic = None): | |
765 | """ | |
766 | Parse a FILE. | |
767 | ||
768 | Specifically: | |
769 | ||
770 | * Raise `StorageBackendRefusal' if that the first line doesn't match | |
771 | MAGIC (if provided). MAGIC should not contain the terminating | |
772 | newline. | |
773 | ||
774 | * Ignore comments (beginning `#') and blank lines. | |
775 | ||
776 | * Call `_parse_line' (provided by the subclass) for other lines. | |
777 | """ | |
778 | with open(file, 'r') as f: | |
779 | if magic is not None: | |
780 | if f.readline().rstrip('\n') != magic: raise StorageBackendRefusal | |
781 | for line in f: | |
782 | line = line.rstrip('\n') | |
783 | if not line or line.startswith('#'): continue | |
784 | me._parse_line(line) | |
785 | ||
786 | def _write_file(me, file, writebody, mode = 0600, magic = None): | |
787 | """ | |
788 | Update FILE atomically. | |
789 | ||
790 | The newly created file will have the given MODE. If MAGIC is given, then | |
791 | write that as the first line. Calls WRITEBODY(F) to write the main body | |
792 | of the file where F is a file object for the new file. | |
793 | """ | |
794 | new = file + '.new' | |
795 | with me._create_file(new, mode) as f: | |
796 | if magic is not None: f.write(magic + '\n') | |
797 | writebody(f) | |
798 | _OS.rename(new, file) | |
799 | ||
800 | def _parse_meta(me, line): | |
801 | """Parse LINE as a metadata NAME=VALUE pair, and updates `_meta'.""" | |
802 | k, v = me._eqsplit(line) | |
803 | me._meta[_dec_metaname(k)] = _dec_metaval(v) | |
804 | ||
805 | def _write_meta(me, f, prefix = ''): | |
806 | """Write the metadata records to F, each with the given PREFIX.""" | |
807 | f.write('\n## Metadata.\n') | |
82910fd3 | 808 | for k, v in _iteritems(me._meta): |
af861fb7 MW |
809 | f.write('%s%s=%s\n' % (prefix, _enc_metaname(k), _enc_metaval(v))) |
810 | ||
811 | def _get_meta(me, name, default): | |
812 | return me._meta.get(name, default) | |
813 | def _put_meta(me, name, value): | |
814 | me._mark_dirty() | |
815 | me._meta[name] = value | |
816 | def _del_meta(me, name): | |
817 | me._mark_dirty() | |
818 | del me._meta[name] | |
819 | def _iter_meta(me): | |
82910fd3 | 820 | return _iteritems(me._meta) |
af861fb7 MW |
821 | |
822 | def _parse_passwd(me, line): | |
823 | """Parse LINE as a password LABEL=PAYLOAD pair, and updates `_pw'.""" | |
824 | k, v = me._eqsplit(line) | |
825 | me._pw[_unb64(k)] = _unb64(v) | |
826 | ||
827 | def _write_passwd(me, f, prefix = ''): | |
828 | """Write the password records to F, each with the given PREFIX.""" | |
829 | f.write('\n## Password data.\n') | |
82910fd3 | 830 | for k, v in _iteritems(me._pw): |
af861fb7 MW |
831 | f.write('%s%s=%s\n' % (prefix, _b64(k), _b64(v))) |
832 | ||
833 | def _get_passwd(me, label): | |
834 | return me._pw[str(label)] | |
835 | def _put_passwd(me, label, payload): | |
836 | me._mark_dirty() | |
837 | me._pw[str(label)] = payload | |
838 | def _del_passwd(me, label): | |
839 | me._mark_dirty() | |
840 | del me._pw[str(label)] | |
841 | def _iter_passwds(me): | |
82910fd3 | 842 | return _iteritems(me._pw) |
af861fb7 MW |
843 | |
844 | class FlatFileStorageBackend (PlainTextBackend): | |
845 | """ | |
846 | I maintain a password database in a plain text file. | |
847 | ||
848 | The text file consists of lines, as follows. | |
849 | ||
850 | * Empty lines, and lines beginning with `#' (in the leftmost column only) | |
851 | are ignored. | |
852 | ||
853 | * Lines of the form `$LABEL=PAYLOAD' store password data. Both LABEL and | |
854 | PAYLOAD are base64-encoded, without `=' padding. | |
855 | ||
856 | * Lines of the form `NAME=VALUE' store metadata. If the NAME contains | |
857 | characters other than alphanumerics, hyphens, underscores, and colons, | |
858 | then it is form-urlencoded, and prefixed wth `!'. If the VALUE | |
859 | contains such characters, then it is base64-encoded, without `=' | |
860 | padding, and prefixed with `?'. | |
861 | ||
862 | * Other lines are erroneous. | |
863 | ||
864 | The file is rewritten from scratch when it's changed: any existing | |
865 | commentary is lost, and items may be reordered. There is no file locking, | |
866 | but the file is updated atomically, by renaming. | |
867 | ||
868 | It is expected that the FlatFileStorageBackend is used mostly for | |
869 | diagnostics and transfer, rather than for a live system. | |
870 | """ | |
871 | ||
872 | NAME = 'flat' | |
873 | PRIO = 0 | |
874 | MAGIC = '### pwsafe password database' | |
875 | ||
876 | def _open(me, file, writep): | |
877 | if not _OS.path.isfile(file): raise StorageBackendRefusal | |
878 | me._parse_file(file, magic = me.MAGIC) | |
879 | def _parse_line(me, line): | |
880 | if line.startswith('$'): me._parse_passwd(line[1:]) | |
881 | else: me._parse_meta(line) | |
882 | ||
883 | def _create(me, file): | |
884 | with me._create_file(file, freshp = True) as f: pass | |
885 | me._file = file | |
886 | me._mark_dirty() | |
887 | ||
888 | def _close(me, abruptp): | |
889 | if not abruptp and me._dirtyp: | |
890 | me._write_file(me._file, me._write_body, magic = me.MAGIC) | |
891 | ||
892 | def _write_body(me, f): | |
893 | me._write_meta(f) | |
894 | me._write_passwd(f, '$') | |
895 | ||
b61e9efe MW |
896 | class DirectoryStorageBackend (PlainTextBackend): |
897 | """ | |
898 | I maintain a password database in a directory, with one file per password. | |
899 | ||
900 | This makes password databases easy to maintain in a revision-control system | |
901 | such as Git. | |
902 | ||
903 | The directory is structured as follows. | |
904 | ||
905 | dir/meta Contains metadata, similar to the `FlatFileBackend'. | |
906 | ||
907 | dir/pw/LABEL Contains the (raw binary) payload for the given password | |
908 | LABEL (base64-encoded, without the useless `=' padding, and | |
909 | with `/' replaced by `.'). | |
910 | ||
911 | dir/tmp/ Contains temporary files used by the implementation. | |
912 | """ | |
913 | ||
914 | NAME = 'dir' | |
915 | METAMAGIC = '### pwsafe password directory metadata' | |
916 | ||
917 | def _open(me, file, writep): | |
918 | if not _OS.path.isdir(file) or \ | |
919 | not _OS.path.isdir(_OS.path.join(file, 'pw')) or \ | |
920 | not _OS.path.isdir(_OS.path.join(file, 'tmp')) or \ | |
921 | not _OS.path.isfile(_OS.path.join(file, 'meta')): | |
922 | raise StorageBackendRefusal | |
923 | me._dir = file | |
924 | me._parse_file(_OS.path.join(file, 'meta'), magic = me.METAMAGIC) | |
925 | def _parse_line(me, line): | |
926 | me._parse_meta(line) | |
927 | ||
928 | def _create(me, file): | |
929 | _OS.mkdir(file, 0700) | |
930 | _OS.mkdir(_OS.path.join(file, 'pw'), 0700) | |
931 | _OS.mkdir(_OS.path.join(file, 'tmp'), 0700) | |
932 | me._mark_dirty() | |
933 | me._dir = file | |
934 | ||
935 | def _close(me, abruptp): | |
936 | if not abruptp and me._dirtyp: | |
937 | me._write_file(_OS.path.join(me._dir, 'meta'), | |
938 | me._write_meta, magic = me.METAMAGIC) | |
939 | ||
940 | def _pwfile(me, label, dir = 'pw'): | |
941 | return _OS.path.join(me._dir, dir, _b64(label).replace('/', '.')) | |
942 | def _get_passwd(me, label): | |
943 | try: | |
944 | f = open(me._pwfile(label), 'rb') | |
a41fd652 MW |
945 | except (OSError, IOError): |
946 | if _excval().errno == _E.ENOENT: raise KeyError(label) | |
b61e9efe MW |
947 | else: raise |
948 | with f: return f.read() | |
949 | def _put_passwd(me, label, payload): | |
950 | new = me._pwfile(label, 'tmp') | |
951 | fd = _OS.open(new, _OS.O_WRONLY | _OS.O_CREAT | _OS.O_TRUNC, 0600) | |
952 | _OS.close(fd) | |
953 | with open(new, 'wb') as f: f.write(payload) | |
954 | _OS.rename(new, me._pwfile(label)) | |
955 | def _del_passwd(me, label): | |
956 | try: | |
957 | _OS.remove(me._pwfile(label)) | |
a41fd652 MW |
958 | except (OSError, IOError): |
959 | if _excval().errno == _E.ENOENT: raise KeyError(label) | |
b61e9efe MW |
960 | else: raise |
961 | def _iter_passwds(me): | |
962 | pw = _OS.path.join(me._dir, 'pw') | |
963 | for i in _OS.listdir(pw): | |
964 | with open(_OS.path.join(pw, i), 'rb') as f: pld = f.read() | |
965 | yield _unb64(i.replace('.', '/')), pld | |
966 | ||
494b719c | 967 | ###-------------------------------------------------------------------------- |
d1c45f5c | 968 | ### Password storage. |
43c09851 | 969 | |
43c09851 | 970 | class PW (object): |
d1c45f5c MW |
971 | """ |
972 | I represent a secure (ish) password store. | |
973 | ||
974 | I can store short secrets, associated with textual names, in a way which | |
975 | doesn't leak too much information about them. | |
976 | ||
2119e334 | 977 | I implement (some of) the Python mapping protocol. |
d1c45f5c | 978 | |
494b719c MW |
979 | I keep track of everything using a StorageBackend object. This contains |
980 | password entries, identified by cryptographic labels, and a number of | |
981 | metadata items. | |
d1c45f5c MW |
982 | |
983 | cipher Names the Catacomb cipher selected. | |
984 | ||
985 | hash Names the Catacomb hash function selected. | |
986 | ||
987 | key Cipher and MAC keys, each prefixed by a 16-bit big-endian | |
988 | length and concatenated, encrypted using the master | |
989 | passphrase. | |
990 | ||
991 | mac Names the Catacomb message authentication code selected. | |
992 | ||
993 | magic A magic string for obscuring password tag names. | |
994 | ||
995 | salt The salt for hashing the passphrase. | |
996 | ||
997 | tag The master passphrase's tag, for the Pixie's benefit. | |
998 | ||
494b719c MW |
999 | Password entries are assigned labels of the form `$' || H(MAGIC || TAG); |
1000 | the corresponding value consists of a pair (TAG, PASSWD), prefixed with | |
1001 | 16-bit lengths, concatenated, padded to a multiple of 256 octets, and | |
1002 | encrypted using the stored keys. | |
d1c45f5c MW |
1003 | """ |
1004 | ||
4a35c9a7 | 1005 | def __init__(me, file, writep = False): |
d1c45f5c | 1006 | """ |
494b719c | 1007 | Initialize a PW object from the database in FILE. |
d1c45f5c | 1008 | |
494b719c MW |
1009 | If WRITEP is false (the default) then the database is opened read-only; |
1010 | if true then it may be written. Requests the database password from the | |
1011 | Pixie, which may cause interaction. | |
d1c45f5c MW |
1012 | """ |
1013 | ||
1014 | ## Open the database. | |
6baae405 | 1015 | me.db = StorageBackend.open(file, writep) |
d1c45f5c MW |
1016 | |
1017 | ## Find out what crypto to use. | |
494b719c MW |
1018 | c = _C.gcciphers[me.db.get_meta('cipher')] |
1019 | h = _C.gchashes[me.db.get_meta('hash')] | |
1020 | m = _C.gcmacs[me.db.get_meta('mac')] | |
d1c45f5c MW |
1021 | |
1022 | ## Request the passphrase and extract the master keys. | |
494b719c MW |
1023 | tag = me.db.get_meta('tag') |
1024 | ppk = PPK(_C.ppread(tag), c, h, m, me.db.get_meta('salt')) | |
43c09851 | 1025 | try: |
494b719c | 1026 | b = _C.ReadBuffer(ppk.decrypt(me.db.get_meta('key'))) |
43c09851 | 1027 | except DecryptError: |
1028 | _C.ppcancel(tag) | |
1029 | raise | |
9a7b948f MW |
1030 | me.ck = b.getblk16() |
1031 | me.mk = b.getblk16() | |
e3b6c0d3 | 1032 | if not b.endp: raise ValueError('trailing junk') |
d1c45f5c MW |
1033 | |
1034 | ## Set the key, and stash it and the tag-hashing secret. | |
43c09851 | 1035 | me.k = Crypto(c, h, m, me.ck, me.mk) |
494b719c | 1036 | me.magic = me.k.decrypt(me.db.get_meta('magic')) |
d1c45f5c | 1037 | |
09b8041d | 1038 | @classmethod |
6baae405 | 1039 | def create(cls, dbcls, file, tag, c, h, m): |
09b8041d | 1040 | """ |
6baae405 | 1041 | Create and initialize a new database FILE using StorageBackend DBCLS. |
09b8041d MW |
1042 | |
1043 | We want a GCipher subclass C, a GHash subclass H, and a GMAC subclass M; | |
1044 | and a Pixie passphrase TAG. | |
1045 | ||
1046 | This doesn't return a working object: it just creates the database file | |
1047 | and gets out of the way. | |
1048 | """ | |
1049 | ||
1050 | ## Set up the cryptography. | |
1051 | pp = _C.ppread(tag, _C.PMODE_VERIFY) | |
1052 | ppk = PPK(pp, c, h, m) | |
1053 | ck = _C.rand.block(c.keysz.default) | |
1054 | mk = _C.rand.block(c.keysz.default) | |
1055 | k = Crypto(c, h, m, ck, mk) | |
1056 | ||
1057 | ## Set up and initialize the database. | |
494b719c | 1058 | kct = ppk.encrypt(_C.WriteBuffer().putblk16(ck).putblk16(mk)) |
6baae405 | 1059 | with dbcls.create(file) as db: |
494b719c MW |
1060 | db.put_meta('tag', tag) |
1061 | db.put_meta('salt', ppk.salt) | |
1062 | db.put_meta('cipher', c.name) | |
1063 | db.put_meta('hash', h.name) | |
1064 | db.put_meta('mac', m.name) | |
1065 | db.put_meta('key', kct) | |
1066 | db.put_meta('magic', k.encrypt(_C.rand.block(h.hashsz))) | |
09b8041d | 1067 | |
43c09851 | 1068 | def keyxform(me, key): |
494b719c MW |
1069 | """Transform the KEY (actually a password tag) into a password label.""" |
1070 | return me.k.h().hash(me.magic).hash(key).done() | |
d1c45f5c | 1071 | |
43c09851 | 1072 | def changepp(me): |
d1c45f5c MW |
1073 | """ |
1074 | Change the database password. | |
1075 | ||
1076 | Requests the new password from the Pixie, which will probably cause | |
1077 | interaction. | |
1078 | """ | |
494b719c | 1079 | tag = me.db.get_meta('tag') |
43c09851 | 1080 | _C.ppcancel(tag) |
1081 | ppk = PPK(_C.ppread(tag, _C.PMODE_VERIFY), | |
d1c45f5c | 1082 | me.k.c.__class__, me.k.h, me.k.m.__class__) |
494b719c MW |
1083 | kct = ppk.encrypt(_C.WriteBuffer().putblk16(me.ck).putblk16(me.mk)) |
1084 | me.db.put_meta('key', kct) | |
1085 | me.db.put_meta('salt', ppk.salt) | |
d1c45f5c | 1086 | |
43c09851 | 1087 | def pack(me, key, value): |
494b719c | 1088 | """Pack the KEY and VALUE into a ciphertext, and return it.""" |
9a7b948f MW |
1089 | b = _C.WriteBuffer() |
1090 | b.putblk16(key).putblk16(value) | |
1091 | b.zero(((b.size + 255) & ~255) - b.size) | |
1092 | return me.k.encrypt(b) | |
d1c45f5c MW |
1093 | |
1094 | def unpack(me, ct): | |
1095 | """ | |
1096 | Unpack a ciphertext CT and return a (KEY, VALUE) pair. | |
1097 | ||
1098 | Might raise DecryptError, of course. | |
1099 | """ | |
9a7b948f MW |
1100 | b = _C.ReadBuffer(me.k.decrypt(ct)) |
1101 | key = b.getblk16() | |
1102 | value = b.getblk16() | |
43c09851 | 1103 | return key, value |
d1c45f5c MW |
1104 | |
1105 | ## Mapping protocol. | |
1106 | ||
43c09851 | 1107 | def __getitem__(me, key): |
494b719c MW |
1108 | """Return the password for the given KEY.""" |
1109 | try: return me.unpack(me.db.get_passwd(me.keyxform(key)))[1] | |
e3b6c0d3 | 1110 | except KeyError: raise KeyError(key) |
d1c45f5c | 1111 | |
43c09851 | 1112 | def __setitem__(me, key, value): |
494b719c MW |
1113 | """Associate the password VALUE with the KEY.""" |
1114 | me.db.put_passwd(me.keyxform(key), me.pack(key, value)) | |
d1c45f5c | 1115 | |
43c09851 | 1116 | def __delitem__(me, key): |
494b719c MW |
1117 | """Forget all about the KEY.""" |
1118 | try: me.db.del_passwd(me.keyxform(key)) | |
e3b6c0d3 | 1119 | except KeyError: raise KeyError(key) |
d1c45f5c | 1120 | |
43c09851 | 1121 | def __iter__(me): |
494b719c MW |
1122 | """Iterate over the known password tags.""" |
1123 | for _, pld in me.db.iter_passwds(): | |
1124 | yield me.unpack(pld)[0] | |
43c09851 | 1125 | |
5bf6e9f5 MW |
1126 | ## Context protocol. |
1127 | ||
1128 | def __enter__(me): | |
1129 | return me | |
1130 | def __exit__(me, excty, excval, exctb): | |
053c2659 | 1131 | me.db.close(excval is not None) |
5bf6e9f5 | 1132 | |
d1c45f5c | 1133 | ###----- That's all, folks -------------------------------------------------- |