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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 | ||
d6542364 MW |
40 | def _iterkeys(dict): return dict.iterkeys() |
41 | def _itervalues(dict): return dict.itervalues() | |
42 | def _iteritems(dict): return dict.iteritems() | |
43 | ||
467c2619 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 | ||
f6d012db MW |
51 | def _excval(): return _SYS.exc_info()[1] |
52 | ||
9ef0b2c9 MW |
53 | _M600 = int("600", 8) |
54 | _M700 = int("700", 8) | |
55 | ||
f6d012db | 56 | ###-------------------------------------------------------------------------- |
af861fb7 MW |
57 | ### Text encoding utilities. |
58 | ||
59 | def _literalp(s): | |
60 | """ | |
61 | Answer whether S can be represented literally. | |
62 | ||
63 | If True, then S can be stored literally, as a metadata item name or | |
64 | value; if False, then S requires some kind of encoding. | |
65 | """ | |
66 | return all(ch.isalnum() or ch in '-_:' for ch in s) | |
67 | ||
68 | def _enc_metaname(name): | |
69 | """Encode NAME as a metadata item name, returning the result.""" | |
70 | if _literalp(name): | |
71 | return name | |
72 | else: | |
73 | sio = _StringIO() | |
74 | sio.write('!') | |
75 | for ch in name: | |
76 | if _literalp(ch): sio.write(ch) | |
77 | elif ch == ' ': sio.write('+') | |
78 | else: sio.write('%%%02x' % ord(ch)) | |
79 | return sio.getvalue() | |
80 | ||
81 | def _dec_metaname(name): | |
82 | """Decode NAME as a metadata item name, returning the result.""" | |
83 | if not name.startswith('!'): | |
84 | return name | |
85 | else: | |
86 | sio = _StringIO() | |
87 | i, n = 1, len(name) | |
88 | while i < n: | |
89 | ch = name[i] | |
90 | i += 1 | |
91 | if ch == '+': | |
92 | sio.write(' ') | |
93 | elif ch == '%': | |
94 | sio.write(chr(int(name[i:i + 2], 16))) | |
95 | i += 2 | |
96 | else: | |
97 | sio.write(ch) | |
98 | return sio.getvalue() | |
99 | ||
100 | def _b64(s): | |
101 | """Encode S as base64, without newlines, and trimming `=' padding.""" | |
3e80d327 | 102 | return s.encode('base64').replace('\n', '').rstrip('=') |
af861fb7 MW |
103 | def _unb64(s): |
104 | """Decode S as base64 with trimmed `=' padding.""" | |
105 | return (s + '='*((4 - len(s))%4)).decode('base64') | |
106 | ||
107 | def _enc_metaval(val): | |
108 | """Encode VAL as a metadata item value, returning the result.""" | |
109 | if _literalp(val): return val | |
110 | else: return '?' + _b64(val) | |
111 | ||
112 | def _dec_metaval(val): | |
113 | """Decode VAL as a metadata item value, returning the result.""" | |
114 | if not val.startswith('?'): return val | |
115 | else: return _unb64(val[1:]) | |
116 | ||
117 | ###-------------------------------------------------------------------------- | |
d1c45f5c MW |
118 | ### Underlying cryptography. |
119 | ||
43c09851 | 120 | class DecryptError (Exception): |
d1c45f5c MW |
121 | """ |
122 | I represent a failure to decrypt a message. | |
123 | ||
124 | Usually this means that someone used the wrong key, though it can also | |
125 | mean that a ciphertext has been modified. | |
126 | """ | |
43c09851 | 127 | pass |
128 | ||
129 | class Crypto (object): | |
d1c45f5c MW |
130 | """ |
131 | I represent a symmetric crypto transform. | |
132 | ||
133 | There's currently only one transform implemented, which is the obvious | |
134 | generic-composition construction: given a message m, and keys K0 and K1, we | |
135 | choose an IV v, and compute: | |
136 | ||
137 | * y = v || E(K0, v; m) | |
138 | * t = M(K1; y) | |
139 | ||
140 | The final ciphertext is t || y. | |
141 | """ | |
142 | ||
43c09851 | 143 | def __init__(me, c, h, m, ck, mk): |
d1c45f5c MW |
144 | """ |
145 | Initialize the Crypto object with a given algorithm selection and keys. | |
146 | ||
147 | We need a GCipher subclass C, a GHash subclass H, a GMAC subclass M, and | |
148 | keys CK and MK for C and M respectively. | |
149 | """ | |
43c09851 | 150 | me.c = c(ck) |
151 | me.m = m(mk) | |
152 | me.h = h | |
d1c45f5c | 153 | |
43c09851 | 154 | def encrypt(me, pt): |
d1c45f5c MW |
155 | """ |
156 | Encrypt the message PT and return the resulting ciphertext. | |
157 | """ | |
9a7b948f MW |
158 | blksz = me.c.__class__.blksz |
159 | b = _C.WriteBuffer() | |
160 | if blksz: | |
161 | iv = _C.rand.block(blksz) | |
43c09851 | 162 | me.c.setiv(iv) |
9a7b948f MW |
163 | b.put(iv) |
164 | b.put(me.c.encrypt(pt)) | |
165 | t = me.m().hash(b).done() | |
166 | return t + str(buffer(b)) | |
167 | ||
43c09851 | 168 | def decrypt(me, ct): |
d1c45f5c MW |
169 | """ |
170 | Decrypt the ciphertext CT, returning the plaintext. | |
171 | ||
172 | Raises DecryptError if anything goes wrong. | |
173 | """ | |
9a7b948f MW |
174 | blksz = me.c.__class__.blksz |
175 | tagsz = me.m.__class__.tagsz | |
176 | b = _C.ReadBuffer(ct) | |
177 | t = b.get(tagsz) | |
178 | h = me.m() | |
179 | if blksz: | |
180 | iv = b.get(blksz) | |
181 | me.c.setiv(iv) | |
182 | h.hash(iv) | |
183 | x = b.get(b.left) | |
184 | h.hash(x) | |
185 | if t != h.done(): raise DecryptError | |
186 | return me.c.decrypt(x) | |
b2687a0a | 187 | |
43c09851 | 188 | class PPK (Crypto): |
d1c45f5c MW |
189 | """ |
190 | I represent a crypto transform whose keys are derived from a passphrase. | |
191 | ||
192 | The password is salted and hashed; the salt is available as the `salt' | |
193 | attribute. | |
194 | """ | |
195 | ||
43c09851 | 196 | def __init__(me, pp, c, h, m, salt = None): |
d1c45f5c MW |
197 | """ |
198 | Initialize the PPK object with a passphrase and algorithm selection. | |
199 | ||
200 | We want a passphrase PP, a GCipher subclass C, a GHash subclass H, a GMAC | |
201 | subclass M, and a SALT. The SALT may be None, if we're generating new | |
202 | keys, indicating that a salt should be chosen randomly. | |
203 | """ | |
43c09851 | 204 | if not salt: salt = _C.rand.block(h.hashsz) |
467c2619 | 205 | tag = pp + _NUL + salt |
43c09851 | 206 | Crypto.__init__(me, c, h, m, |
467c2619 MW |
207 | h().hash(_CIPHER).hash(tag).done(), |
208 | h().hash(_MAC).hash(tag).done()) | |
43c09851 | 209 | me.salt = salt |
210 | ||
d1c45f5c | 211 | ###-------------------------------------------------------------------------- |
494b719c MW |
212 | ### Backend storage. |
213 | ||
6baae405 MW |
214 | class StorageBackendRefusal (Exception): |
215 | """ | |
216 | I signify that a StorageBackend subclass has refused to open a file. | |
217 | ||
218 | This is used by the StorageBackend.open class method. | |
219 | """ | |
220 | pass | |
221 | ||
222 | class StorageBackendClass (type): | |
223 | """ | |
224 | I am a metaclass for StorageBackend classes. | |
225 | ||
226 | My main feature is that I register my concrete instances (with a `NAME' | |
227 | which is not `None') with the StorageBackend class. | |
228 | """ | |
229 | def __init__(me, name, supers, dict): | |
230 | """ | |
231 | Register a new concrete StorageBackend subclass. | |
232 | """ | |
233 | super(StorageBackendClass, me).__init__(name, supers, dict) | |
234 | if me.NAME is not None: StorageBackend.register_concrete_subclass(me) | |
235 | ||
494b719c MW |
236 | class StorageBackend (object): |
237 | """ | |
1726ab40 MW |
238 | I provide basic protocol for password storage backends. |
239 | ||
240 | I'm an abstract class: you want one of my subclasses if you actually want | |
6baae405 MW |
241 | to do something useful. But I maintain a list of my subclasses and can |
242 | choose an appropriate one to open a database file you've found lying about. | |
494b719c MW |
243 | |
244 | Backends are responsible for storing and retrieving stuff, but not for the | |
245 | cryptographic details. Backends need to store two kinds of information: | |
246 | ||
247 | * metadata, consisting of a number of property names and their values; | |
248 | and | |
249 | ||
250 | * password mappings, consisting of a number of binary labels and | |
251 | payloads. | |
1726ab40 MW |
252 | |
253 | Backends need to implement the following ordinary methods. See the calling | |
254 | methods for details of the subclass responsibilities. | |
255 | ||
256 | BE._create(FILE) Create a new database in FILE; used by `create'. | |
257 | ||
258 | BE._open(FILE, WRITEP) | |
259 | Open the existing database FILE; used by `open'. | |
260 | ||
053c2659 MW |
261 | BE._close(ABRUPTP) Close the database, freeing up any resources. If |
262 | ABRUPTP then don't try to commit changes. | |
1726ab40 MW |
263 | |
264 | BE._get_meta(NAME, DEFAULT) | |
265 | Return the value of the metadata item with the given | |
266 | NAME, or DEFAULT if it doesn't exist; used by | |
267 | `get_meta'. | |
268 | ||
269 | BE._put_meta(NAME, VALUE) | |
270 | Set the VALUE of the metadata item with the given | |
271 | NAME, creating one if necessary; used by `put_meta'. | |
272 | ||
273 | BE._del_meta(NAME) Forget the metadata item with the given NAME; raise | |
274 | `KeyError' if there is no such item; used by | |
275 | `del_meta'. | |
276 | ||
277 | BE._iter_meta() Return an iterator over the metadata (NAME, VALUE) | |
278 | pairs; used by `iter_meta'. | |
279 | ||
280 | BE._get_passwd(LABEL) | |
281 | Return the password payload stored with the (binary) | |
282 | LABEL; used by `get_passwd'. | |
283 | ||
284 | BE._put_passwd(LABEL, PAYLOAD) | |
285 | Associate the (binary) PAYLOAD with the LABEL, | |
286 | forgetting any previous payload for that LABEL; used | |
287 | by `put_passwd'. | |
288 | ||
289 | BE._del_passwd(LABEL) Forget the password record with the given LABEL; used | |
290 | by `_del_passwd'. | |
291 | ||
292 | BE._iter_passwds() Return an iterator over the password (LABEL, PAYLOAD) | |
293 | pairs; used by `iter_passwds'. | |
6baae405 MW |
294 | |
295 | Also, concrete subclasses should define the following class attributes. | |
296 | ||
297 | NAME The name of the backend, so that the user can select | |
298 | it when creating a new database. | |
299 | ||
300 | PRIO An integer priority: backends are tried in decreasing | |
301 | priority order when opening an existing database. | |
494b719c MW |
302 | """ |
303 | ||
6baae405 MW |
304 | __metaclass__ = StorageBackendClass |
305 | NAME = None | |
306 | PRIO = 10 | |
307 | ||
308 | ## The registry of subclasses. | |
309 | CLASSES = {} | |
310 | ||
494b719c MW |
311 | FAIL = ['FAIL'] |
312 | ||
6baae405 MW |
313 | @staticmethod |
314 | def register_concrete_subclass(sub): | |
315 | """Register a concrete subclass, so that `open' can try it.""" | |
316 | StorageBackend.CLASSES[sub.NAME] = sub | |
317 | ||
318 | @staticmethod | |
319 | def byname(name): | |
320 | """ | |
321 | Return the concrete subclass with the given NAME. | |
322 | ||
323 | Raise `KeyError' if the name isn't found. | |
324 | """ | |
325 | return StorageBackend.CLASSES[name] | |
326 | ||
327 | @staticmethod | |
328 | def classes(): | |
329 | """Return an iterator over the concrete subclasses.""" | |
d6542364 | 330 | return _itervalues(StorageBackend.CLASSES) |
6baae405 MW |
331 | |
332 | @staticmethod | |
333 | def open(file, writep = False): | |
334 | """Open a database FILE, using some appropriate backend.""" | |
335 | _OS.stat(file) | |
336 | for cls in sorted(StorageBackend.CLASSES.values(), reverse = True, | |
337 | key = lambda cls: cls.PRIO): | |
338 | try: return cls(file, writep) | |
339 | except StorageBackendRefusal: pass | |
340 | raise StorageBackendRefusal | |
494b719c MW |
341 | |
342 | @classmethod | |
343 | def create(cls, file): | |
1726ab40 MW |
344 | """ |
345 | Create a new database in the named FILE, using this backend. | |
346 | ||
347 | Subclasses must implement the `_create' instance method. | |
348 | """ | |
494b719c | 349 | return cls(writep = True, _magic = lambda me: me._create(file)) |
494b719c MW |
350 | |
351 | def __init__(me, file = None, writep = False, _magic = None, *args, **kw): | |
352 | """ | |
353 | Main constructor. | |
1726ab40 MW |
354 | |
355 | Subclasses are not, in general, expected to override this: there's a | |
356 | somewhat hairy protocol between the constructor and some of the class | |
357 | methods. Instead, the main hook for customization is the subclass's | |
358 | `_open' method, which is invoked in the usual case. | |
494b719c MW |
359 | """ |
360 | super(StorageBackend, me).__init__(*args, **kw) | |
1c7419c9 | 361 | if me.NAME is None: raise ValueError('abstract class') |
494b719c | 362 | if _magic is not None: _magic(me) |
1c7419c9 | 363 | elif file is None: raise ValueError('missing file parameter') |
1726ab40 | 364 | else: me._open(file, writep) |
494b719c MW |
365 | me._writep = writep |
366 | me._livep = True | |
367 | ||
053c2659 | 368 | def close(me, abruptp = False): |
494b719c MW |
369 | """ |
370 | Close the database. | |
371 | ||
372 | It is harmless to attempt to close a database which has been closed | |
1726ab40 | 373 | already. Calls the subclass's `_close' method. |
494b719c MW |
374 | """ |
375 | if me._livep: | |
376 | me._livep = False | |
053c2659 | 377 | me._close(abruptp) |
494b719c MW |
378 | |
379 | ## Utilities. | |
380 | ||
381 | def _check_live(me): | |
382 | """Raise an error if the receiver has been closed.""" | |
1c7419c9 | 383 | if not me._livep: raise ValueError('database is closed') |
494b719c MW |
384 | |
385 | def _check_write(me): | |
386 | """Raise an error if the receiver is not open for writing.""" | |
387 | me._check_live() | |
1c7419c9 | 388 | if not me._writep: raise ValueError('database is read-only') |
494b719c MW |
389 | |
390 | def _check_meta_name(me, name): | |
391 | """ | |
392 | Raise an error unless NAME is a valid name for a metadata item. | |
393 | ||
394 | Metadata names may not start with `$': such names are reserved for | |
395 | password storage. | |
396 | """ | |
397 | if name.startswith('$'): | |
1c7419c9 | 398 | raise ValueError("invalid metadata key `%s'" % name) |
494b719c MW |
399 | |
400 | ## Context protocol. | |
401 | ||
402 | def __enter__(me): | |
403 | """Context protocol: make sure the database is closed on exit.""" | |
404 | return me | |
405 | def __exit__(me, exctype, excvalue, exctb): | |
406 | """Context protocol: see `__enter__'.""" | |
053c2659 | 407 | me.close(excvalue is not None) |
494b719c MW |
408 | |
409 | ## Metadata. | |
410 | ||
411 | def get_meta(me, name, default = FAIL): | |
412 | """ | |
413 | Fetch the value for the metadata item NAME. | |
414 | ||
415 | If no such item exists, then return DEFAULT if that was set; otherwise | |
416 | raise a `KeyError'. | |
1726ab40 MW |
417 | |
418 | This calls the subclass's `_get_meta' method, which should return the | |
419 | requested item or return the given DEFAULT value. It may assume that the | |
420 | name is valid and the database is open. | |
494b719c MW |
421 | """ |
422 | me._check_meta_name(name) | |
423 | me._check_live() | |
1726ab40 | 424 | value = me._get_meta(name, default) |
1c7419c9 | 425 | if value is StorageBackend.FAIL: raise KeyError(name) |
494b719c MW |
426 | return value |
427 | ||
428 | def put_meta(me, name, value): | |
1726ab40 MW |
429 | """ |
430 | Store VALUE in the metadata item called NAME. | |
431 | ||
432 | This calls the subclass's `_put_meta' method, which may assume that the | |
433 | name is valid and the database is open for writing. | |
434 | """ | |
494b719c MW |
435 | me._check_meta_name(name) |
436 | me._check_write() | |
1726ab40 | 437 | me._put_meta(name, value) |
494b719c MW |
438 | |
439 | def del_meta(me, name): | |
1726ab40 MW |
440 | """ |
441 | Forget about the metadata item with the given NAME. | |
442 | ||
443 | This calls the subclass's `_del_meta' method, which may assume that the | |
444 | name is valid and the database is open for writing. | |
445 | """ | |
494b719c MW |
446 | me._check_meta_name(name) |
447 | me._check_write() | |
1726ab40 | 448 | me._del_meta(name) |
494b719c MW |
449 | |
450 | def iter_meta(me): | |
1726ab40 MW |
451 | """ |
452 | Return an iterator over the name/value metadata items. | |
494b719c | 453 | |
1726ab40 MW |
454 | This calls the subclass's `_iter_meta' method, which may assume that the |
455 | database is open. | |
456 | """ | |
457 | me._check_live() | |
458 | return me._iter_meta() | |
494b719c MW |
459 | |
460 | def get_passwd(me, label): | |
461 | """ | |
462 | Fetch and return the payload stored with the (opaque, binary) LABEL. | |
463 | ||
464 | If there is no such payload then raise `KeyError'. | |
1726ab40 MW |
465 | |
466 | This calls the subclass's `_get_passwd' method, which may assume that the | |
467 | database is open. | |
494b719c MW |
468 | """ |
469 | me._check_live() | |
1726ab40 | 470 | return me._get_passwd(label) |
494b719c MW |
471 | |
472 | def put_passwd(me, label, payload): | |
473 | """ | |
474 | Associate the (opaque, binary) PAYLOAD with the (opaque, binary) LABEL. | |
475 | ||
476 | Any previous payload for LABEL is forgotten. | |
1726ab40 MW |
477 | |
478 | This calls the subclass's `_put_passwd' method, which may assume that the | |
479 | database is open for writing. | |
494b719c MW |
480 | """ |
481 | me._check_write() | |
1726ab40 | 482 | me._put_passwd(label, payload) |
494b719c MW |
483 | |
484 | def del_passwd(me, label): | |
485 | """ | |
486 | Forget any PAYLOAD associated with the (opaque, binary) LABEL. | |
487 | ||
488 | If there is no such payload then raise `KeyError'. | |
1726ab40 MW |
489 | |
490 | This calls the subclass's `_del_passwd' method, which may assume that the | |
491 | database is open for writing. | |
494b719c MW |
492 | """ |
493 | me._check_write() | |
1d93191e | 494 | me._del_passwd(label) |
494b719c MW |
495 | |
496 | def iter_passwds(me): | |
1726ab40 MW |
497 | """ |
498 | Return an iterator over the stored password label/payload pairs. | |
499 | ||
500 | This calls the subclass's `_iter_passwds' method, which may assume that | |
501 | the database is open. | |
502 | """ | |
494b719c | 503 | me._check_live() |
1726ab40 MW |
504 | return me._iter_passwds() |
505 | ||
8501dc39 MW |
506 | try: import gdbm as _G |
507 | except ImportError: pass | |
508 | else: | |
509 | class GDBMStorageBackend (StorageBackend): | |
510 | """ | |
511 | My instances store password data in a GDBM database. | |
1726ab40 | 512 | |
8501dc39 MW |
513 | Metadata and password entries are mixed into the same database. The key |
514 | for a metadata item is simply its name; the key for a password entry is | |
515 | the entry's label prefixed by `$', since we're guaranteed that no | |
516 | metadata item name begins with `$'. | |
517 | """ | |
1726ab40 | 518 | |
8501dc39 | 519 | NAME = 'gdbm' |
6baae405 | 520 | |
8501dc39 MW |
521 | def _open(me, file, writep): |
522 | try: me._db = _G.open(file, writep and 'w' or 'r') | |
f6d012db | 523 | except _G.error: raise StorageBackendRefusal(_excval()) |
1726ab40 | 524 | |
8501dc39 | 525 | def _create(me, file): |
9ef0b2c9 | 526 | me._db = _G.open(file, 'n', _M600) |
1726ab40 | 527 | |
8501dc39 MW |
528 | def _close(me, abruptp): |
529 | me._db.close() | |
530 | me._db = None | |
1726ab40 | 531 | |
8501dc39 MW |
532 | def _get_meta(me, name, default): |
533 | try: return me._db[name] | |
534 | except KeyError: return default | |
1726ab40 | 535 | |
8501dc39 MW |
536 | def _put_meta(me, name, value): |
537 | me._db[name] = value | |
1726ab40 | 538 | |
8501dc39 MW |
539 | def _del_meta(me, name): |
540 | del me._db[name] | |
1726ab40 | 541 | |
8501dc39 MW |
542 | def _iter_meta(me): |
543 | k = me._db.firstkey() | |
544 | while k is not None: | |
545 | if not k.startswith('$'): yield k, me._db[k] | |
546 | k = me._db.nextkey(k) | |
1726ab40 | 547 | |
8501dc39 MW |
548 | def _get_passwd(me, label): |
549 | return me._db['$' + label] | |
1726ab40 | 550 | |
8501dc39 MW |
551 | def _put_passwd(me, label, payload): |
552 | me._db['$' + label] = payload | |
1726ab40 | 553 | |
8501dc39 MW |
554 | def _del_passwd(me, label): |
555 | del me._db['$' + label] | |
1726ab40 | 556 | |
8501dc39 MW |
557 | def _iter_passwds(me): |
558 | k = me._db.firstkey() | |
559 | while k is not None: | |
560 | if k.startswith('$'): yield k[1:], me._db[k] | |
561 | k = me._db.nextkey(k) | |
494b719c | 562 | |
e92f9aa2 MW |
563 | try: import sqlite3 as _Q |
564 | except ImportError: pass | |
565 | else: | |
566 | class SQLiteStorageBackend (StorageBackend): | |
567 | """ | |
568 | I represent a password database stored in SQLite. | |
569 | ||
570 | Metadata and password items are stored in separate tables, so there's no | |
571 | conflict. Some additional metadata is stored in the `meta' table, with | |
572 | names beginning with `$' so as not to conflict with clients: | |
573 | ||
574 | $version The schema version of the table. | |
575 | """ | |
576 | ||
577 | NAME = 'sqlite' | |
578 | VERSION = 0 | |
579 | ||
580 | def _open(me, file, writep): | |
581 | try: | |
582 | me._db = _Q.connect(file) | |
583 | ver = me._query_scalar( | |
584 | "SELECT value FROM meta WHERE name = '$version'", | |
585 | "version check") | |
f6d012db MW |
586 | except (_Q.DatabaseError, _Q.OperationalError): |
587 | raise StorageBackendRefusal(_excval()) | |
1c7419c9 | 588 | if ver is None: raise ValueError('database broken (missing $version)') |
e92f9aa2 | 589 | elif ver < me.VERSION: me._upgrade(ver) |
1c7419c9 MW |
590 | elif ver > me.VERSION: raise ValueError \ |
591 | ('unknown database schema version (%d > %d)' % (ver, me.VERSION)) | |
e92f9aa2 MW |
592 | |
593 | def _create(me, file): | |
9ef0b2c9 | 594 | fd = _OS.open(file, _OS.O_WRONLY | _OS.O_CREAT | _OS.O_EXCL, _M600) |
e92f9aa2 MW |
595 | _OS.close(fd) |
596 | try: | |
597 | me._db = _Q.connect(file) | |
598 | c = me._db.cursor() | |
599 | c.execute(""" | |
600 | CREATE TABLE meta ( | |
601 | name TEXT PRIMARY KEY NOT NULL, | |
602 | value BLOB NOT NULL); | |
603 | """) | |
604 | c.execute(""" | |
605 | CREATE TABLE passwd ( | |
606 | label BLOB PRIMARY KEY NOT NULL, | |
607 | payload BLOB NOT NULL); | |
608 | """) | |
609 | c.execute(""" | |
610 | INSERT INTO meta (name, value) VALUES ('$version', ?); | |
611 | """, [me.VERSION]) | |
612 | except: | |
613 | try: _OS.unlink(file) | |
614 | except OSError: pass | |
615 | raise | |
616 | ||
617 | def _upgrade(me, ver): | |
618 | """Upgrade the database from schema version VER.""" | |
619 | assert False, 'how embarrassing' | |
620 | ||
621 | def _close(me, abruptp): | |
622 | if not abruptp: me._db.commit() | |
623 | me._db.close() | |
624 | me._db = None | |
625 | ||
626 | def _fetch_scalar(me, c, what, default = None): | |
627 | try: row = next(c) | |
628 | except StopIteration: val = default | |
629 | else: val, = row | |
630 | try: row = next(c) | |
631 | except StopIteration: pass | |
1c7419c9 | 632 | else: raise ValueError('multiple matching records for %s' % what) |
e92f9aa2 MW |
633 | return val |
634 | ||
635 | def _query_scalar(me, query, what, default = None, args = []): | |
636 | c = me._db.cursor() | |
637 | c.execute(query, args) | |
638 | return me._fetch_scalar(c, what, default) | |
639 | ||
640 | def _get_meta(me, name, default): | |
641 | v = me._query_scalar("SELECT value FROM meta WHERE name = ?", | |
642 | "metadata item `%s'" % name, | |
643 | default = default, args = [name]) | |
644 | if v is default: return v | |
645 | else: return str(v) | |
646 | ||
647 | def _put_meta(me, name, value): | |
648 | c = me._db.cursor() | |
649 | c.execute("INSERT OR REPLACE INTO meta (name, value) VALUES (?, ?)", | |
650 | [name, buffer(value)]) | |
651 | ||
652 | def _del_meta(me, name): | |
653 | c = me._db.cursor() | |
654 | c.execute("DELETE FROM meta WHERE name = ?", [name]) | |
1c7419c9 | 655 | if not c.rowcount: raise KeyError(name) |
e92f9aa2 MW |
656 | |
657 | def _iter_meta(me): | |
658 | c = me._db.cursor() | |
659 | c.execute("SELECT name, value FROM meta WHERE name NOT LIKE '$%'") | |
660 | for k, v in c: yield k, str(v) | |
661 | ||
662 | def _get_passwd(me, label): | |
663 | pld = me._query_scalar("SELECT payload FROM passwd WHERE label = ?", | |
664 | "password", default = None, | |
665 | args = [buffer(label)]) | |
1c7419c9 | 666 | if pld is None: raise KeyError(label) |
e92f9aa2 MW |
667 | return str(pld) |
668 | ||
669 | def _put_passwd(me, label, payload): | |
670 | c = me._db.cursor() | |
671 | c.execute("INSERT OR REPLACE INTO passwd (label, payload) " | |
672 | "VALUES (?, ?)", | |
673 | [buffer(label), buffer(payload)]) | |
674 | ||
675 | def _del_passwd(me, label): | |
676 | c = me._db.cursor() | |
677 | c.execute("DELETE FROM passwd WHERE label = ?", [label]) | |
1c7419c9 | 678 | if not c.rowcount: raise KeyError(label) |
e92f9aa2 MW |
679 | |
680 | def _iter_passwds(me): | |
681 | c = me._db.cursor() | |
682 | c.execute("SELECT label, payload FROM passwd") | |
683 | for k, v in c: yield str(k), str(v) | |
684 | ||
af861fb7 MW |
685 | class PlainTextBackend (StorageBackend): |
686 | """ | |
687 | I'm a utility base class for storage backends which use plain text files. | |
688 | ||
689 | I provide subclasses with the following capabilities. | |
690 | ||
691 | * Creating files, with given modes, optionally ensuring that the file | |
692 | doesn't exist already. | |
693 | ||
694 | * Parsing flat text files, checking leading magic, skipping comments, and | |
695 | providing standard encodings of troublesome characters and binary | |
696 | strings in metadata and password records. See below. | |
697 | ||
698 | * Maintenance of metadata and password records in in-memory dictionaries, | |
699 | with ready implementations of the necessary StorageBackend subclass | |
700 | responsibility methods. (Subclasses can override these if they want to | |
701 | make different arrangements.) | |
702 | ||
703 | Metadata records are written with an optional prefix string chosen by the | |
704 | caller, followed by a `NAME=VALUE' pair. The NAME is form-urlencoded and | |
705 | prefixed with `!' if it contains strange characters; the VALUE is base64- | |
706 | encoded (without the pointless trailing `=' padding) and prefixed with `?' | |
707 | if necessary. | |
708 | ||
709 | Password records are written with an optional prefix string chosen by the | |
710 | caller, followed by a LABEL=PAYLOAD pair, both of which are base64-encoded | |
711 | (without padding). | |
712 | ||
713 | The following attributes are available for subclasses: | |
714 | ||
715 | _meta Dictionary mapping metadata item names to their values. | |
716 | Populated by `_parse_meta' and managed by `_get_meta' and | |
717 | friends. | |
718 | ||
719 | _pw Dictionary mapping password labels to encrypted payloads. | |
720 | Populated by `_parse_passwd' and managed by `_get_passwd' and | |
721 | friends. | |
722 | ||
723 | _dirtyp Boolean: set if either of the dictionaries has been modified. | |
724 | """ | |
725 | ||
726 | def __init__(me, *args, **kw): | |
727 | """ | |
728 | Hook for initialization. | |
729 | ||
730 | Sets up the published instance attributes. | |
731 | """ | |
732 | me._meta = {} | |
733 | me._pw = {} | |
734 | me._dirtyp = False | |
735 | super(PlainTextBackend, me).__init__(*args, **kw) | |
736 | ||
9ef0b2c9 | 737 | def _create_file(me, file, mode = _M600, freshp = False): |
af861fb7 MW |
738 | """ |
739 | Make sure FILE exists, creating it with the given MODE if necessary. | |
740 | ||
741 | If FRESHP is true, then make sure the file did not exist previously. | |
742 | Return a file object for the newly created file. | |
743 | """ | |
744 | flags = _OS.O_CREAT | _OS.O_WRONLY | |
745 | if freshp: flags |= _OS.O_EXCL | |
746 | else: flags |= _OS.O_TRUNC | |
747 | fd = _OS.open(file, flags, mode) | |
748 | return _OS.fdopen(fd, 'w') | |
749 | ||
750 | def _mark_dirty(me): | |
751 | """ | |
752 | Set the `_dirtyp' flag. | |
753 | ||
754 | Subclasses might find it useful to intercept this method. | |
755 | """ | |
756 | me._dirtyp = True | |
757 | ||
758 | def _eqsplit(me, line): | |
759 | """ | |
760 | Extract the KEY, VALUE pair from a LINE of the form `KEY=VALUE'. | |
761 | ||
762 | Raise `ValueError' if there is no `=' in the LINE. | |
763 | """ | |
764 | eq = line.index('=') | |
765 | return line[:eq], line[eq + 1:] | |
766 | ||
767 | def _parse_file(me, file, magic = None): | |
768 | """ | |
769 | Parse a FILE. | |
770 | ||
771 | Specifically: | |
772 | ||
773 | * Raise `StorageBackendRefusal' if that the first line doesn't match | |
774 | MAGIC (if provided). MAGIC should not contain the terminating | |
775 | newline. | |
776 | ||
777 | * Ignore comments (beginning `#') and blank lines. | |
778 | ||
779 | * Call `_parse_line' (provided by the subclass) for other lines. | |
780 | """ | |
781 | with open(file, 'r') as f: | |
782 | if magic is not None: | |
783 | if f.readline().rstrip('\n') != magic: raise StorageBackendRefusal | |
784 | for line in f: | |
785 | line = line.rstrip('\n') | |
786 | if not line or line.startswith('#'): continue | |
787 | me._parse_line(line) | |
788 | ||
9ef0b2c9 | 789 | def _write_file(me, file, writebody, mode = _M600, magic = None): |
af861fb7 MW |
790 | """ |
791 | Update FILE atomically. | |
792 | ||
793 | The newly created file will have the given MODE. If MAGIC is given, then | |
794 | write that as the first line. Calls WRITEBODY(F) to write the main body | |
795 | of the file where F is a file object for the new file. | |
796 | """ | |
797 | new = file + '.new' | |
798 | with me._create_file(new, mode) as f: | |
799 | if magic is not None: f.write(magic + '\n') | |
800 | writebody(f) | |
801 | _OS.rename(new, file) | |
802 | ||
803 | def _parse_meta(me, line): | |
804 | """Parse LINE as a metadata NAME=VALUE pair, and updates `_meta'.""" | |
805 | k, v = me._eqsplit(line) | |
806 | me._meta[_dec_metaname(k)] = _dec_metaval(v) | |
807 | ||
808 | def _write_meta(me, f, prefix = ''): | |
809 | """Write the metadata records to F, each with the given PREFIX.""" | |
810 | f.write('\n## Metadata.\n') | |
d6542364 | 811 | for k, v in _iteritems(me._meta): |
af861fb7 MW |
812 | f.write('%s%s=%s\n' % (prefix, _enc_metaname(k), _enc_metaval(v))) |
813 | ||
814 | def _get_meta(me, name, default): | |
815 | return me._meta.get(name, default) | |
816 | def _put_meta(me, name, value): | |
817 | me._mark_dirty() | |
818 | me._meta[name] = value | |
819 | def _del_meta(me, name): | |
820 | me._mark_dirty() | |
821 | del me._meta[name] | |
822 | def _iter_meta(me): | |
d6542364 | 823 | return _iteritems(me._meta) |
af861fb7 MW |
824 | |
825 | def _parse_passwd(me, line): | |
826 | """Parse LINE as a password LABEL=PAYLOAD pair, and updates `_pw'.""" | |
827 | k, v = me._eqsplit(line) | |
828 | me._pw[_unb64(k)] = _unb64(v) | |
829 | ||
830 | def _write_passwd(me, f, prefix = ''): | |
831 | """Write the password records to F, each with the given PREFIX.""" | |
832 | f.write('\n## Password data.\n') | |
d6542364 | 833 | for k, v in _iteritems(me._pw): |
af861fb7 MW |
834 | f.write('%s%s=%s\n' % (prefix, _b64(k), _b64(v))) |
835 | ||
836 | def _get_passwd(me, label): | |
837 | return me._pw[str(label)] | |
838 | def _put_passwd(me, label, payload): | |
839 | me._mark_dirty() | |
840 | me._pw[str(label)] = payload | |
841 | def _del_passwd(me, label): | |
842 | me._mark_dirty() | |
843 | del me._pw[str(label)] | |
844 | def _iter_passwds(me): | |
d6542364 | 845 | return _iteritems(me._pw) |
af861fb7 MW |
846 | |
847 | class FlatFileStorageBackend (PlainTextBackend): | |
848 | """ | |
849 | I maintain a password database in a plain text file. | |
850 | ||
851 | The text file consists of lines, as follows. | |
852 | ||
853 | * Empty lines, and lines beginning with `#' (in the leftmost column only) | |
854 | are ignored. | |
855 | ||
856 | * Lines of the form `$LABEL=PAYLOAD' store password data. Both LABEL and | |
857 | PAYLOAD are base64-encoded, without `=' padding. | |
858 | ||
859 | * Lines of the form `NAME=VALUE' store metadata. If the NAME contains | |
860 | characters other than alphanumerics, hyphens, underscores, and colons, | |
861 | then it is form-urlencoded, and prefixed wth `!'. If the VALUE | |
862 | contains such characters, then it is base64-encoded, without `=' | |
863 | padding, and prefixed with `?'. | |
864 | ||
865 | * Other lines are erroneous. | |
866 | ||
867 | The file is rewritten from scratch when it's changed: any existing | |
868 | commentary is lost, and items may be reordered. There is no file locking, | |
869 | but the file is updated atomically, by renaming. | |
870 | ||
871 | It is expected that the FlatFileStorageBackend is used mostly for | |
872 | diagnostics and transfer, rather than for a live system. | |
873 | """ | |
874 | ||
875 | NAME = 'flat' | |
876 | PRIO = 0 | |
877 | MAGIC = '### pwsafe password database' | |
878 | ||
879 | def _open(me, file, writep): | |
880 | if not _OS.path.isfile(file): raise StorageBackendRefusal | |
881 | me._parse_file(file, magic = me.MAGIC) | |
882 | def _parse_line(me, line): | |
883 | if line.startswith('$'): me._parse_passwd(line[1:]) | |
884 | else: me._parse_meta(line) | |
885 | ||
886 | def _create(me, file): | |
887 | with me._create_file(file, freshp = True) as f: pass | |
888 | me._file = file | |
889 | me._mark_dirty() | |
890 | ||
891 | def _close(me, abruptp): | |
892 | if not abruptp and me._dirtyp: | |
893 | me._write_file(me._file, me._write_body, magic = me.MAGIC) | |
894 | ||
895 | def _write_body(me, f): | |
896 | me._write_meta(f) | |
897 | me._write_passwd(f, '$') | |
898 | ||
b61e9efe MW |
899 | class DirectoryStorageBackend (PlainTextBackend): |
900 | """ | |
901 | I maintain a password database in a directory, with one file per password. | |
902 | ||
903 | This makes password databases easy to maintain in a revision-control system | |
904 | such as Git. | |
905 | ||
906 | The directory is structured as follows. | |
907 | ||
908 | dir/meta Contains metadata, similar to the `FlatFileBackend'. | |
909 | ||
910 | dir/pw/LABEL Contains the (raw binary) payload for the given password | |
911 | LABEL (base64-encoded, without the useless `=' padding, and | |
912 | with `/' replaced by `.'). | |
913 | ||
914 | dir/tmp/ Contains temporary files used by the implementation. | |
915 | """ | |
916 | ||
917 | NAME = 'dir' | |
918 | METAMAGIC = '### pwsafe password directory metadata' | |
919 | ||
920 | def _open(me, file, writep): | |
921 | if not _OS.path.isdir(file) or \ | |
922 | not _OS.path.isdir(_OS.path.join(file, 'pw')) or \ | |
923 | not _OS.path.isdir(_OS.path.join(file, 'tmp')) or \ | |
924 | not _OS.path.isfile(_OS.path.join(file, 'meta')): | |
925 | raise StorageBackendRefusal | |
926 | me._dir = file | |
927 | me._parse_file(_OS.path.join(file, 'meta'), magic = me.METAMAGIC) | |
928 | def _parse_line(me, line): | |
929 | me._parse_meta(line) | |
930 | ||
931 | def _create(me, file): | |
9ef0b2c9 MW |
932 | _OS.mkdir(file, _M700) |
933 | _OS.mkdir(_OS.path.join(file, 'pw'), _M700) | |
934 | _OS.mkdir(_OS.path.join(file, 'tmp'), _M700) | |
b61e9efe MW |
935 | me._mark_dirty() |
936 | me._dir = file | |
937 | ||
938 | def _close(me, abruptp): | |
939 | if not abruptp and me._dirtyp: | |
940 | me._write_file(_OS.path.join(me._dir, 'meta'), | |
941 | me._write_meta, magic = me.METAMAGIC) | |
942 | ||
943 | def _pwfile(me, label, dir = 'pw'): | |
944 | return _OS.path.join(me._dir, dir, _b64(label).replace('/', '.')) | |
945 | def _get_passwd(me, label): | |
946 | try: | |
947 | f = open(me._pwfile(label), 'rb') | |
f6d012db MW |
948 | except (OSError, IOError): |
949 | if _excval().errno == _E.ENOENT: raise KeyError(label) | |
b61e9efe MW |
950 | else: raise |
951 | with f: return f.read() | |
952 | def _put_passwd(me, label, payload): | |
953 | new = me._pwfile(label, 'tmp') | |
9ef0b2c9 | 954 | fd = _OS.open(new, _OS.O_WRONLY | _OS.O_CREAT | _OS.O_TRUNC, _M600) |
b61e9efe MW |
955 | _OS.close(fd) |
956 | with open(new, 'wb') as f: f.write(payload) | |
957 | _OS.rename(new, me._pwfile(label)) | |
958 | def _del_passwd(me, label): | |
959 | try: | |
960 | _OS.remove(me._pwfile(label)) | |
f6d012db MW |
961 | except (OSError, IOError): |
962 | if _excval().errno == _E.ENOENT: raise KeyError(label) | |
b61e9efe MW |
963 | else: raise |
964 | def _iter_passwds(me): | |
965 | pw = _OS.path.join(me._dir, 'pw') | |
966 | for i in _OS.listdir(pw): | |
967 | with open(_OS.path.join(pw, i), 'rb') as f: pld = f.read() | |
968 | yield _unb64(i.replace('.', '/')), pld | |
969 | ||
494b719c | 970 | ###-------------------------------------------------------------------------- |
d1c45f5c | 971 | ### Password storage. |
43c09851 | 972 | |
43c09851 | 973 | class PW (object): |
d1c45f5c MW |
974 | """ |
975 | I represent a secure (ish) password store. | |
976 | ||
977 | I can store short secrets, associated with textual names, in a way which | |
978 | doesn't leak too much information about them. | |
979 | ||
2119e334 | 980 | I implement (some of) the Python mapping protocol. |
d1c45f5c | 981 | |
494b719c MW |
982 | I keep track of everything using a StorageBackend object. This contains |
983 | password entries, identified by cryptographic labels, and a number of | |
984 | metadata items. | |
d1c45f5c MW |
985 | |
986 | cipher Names the Catacomb cipher selected. | |
987 | ||
988 | hash Names the Catacomb hash function selected. | |
989 | ||
990 | key Cipher and MAC keys, each prefixed by a 16-bit big-endian | |
991 | length and concatenated, encrypted using the master | |
992 | passphrase. | |
993 | ||
994 | mac Names the Catacomb message authentication code selected. | |
995 | ||
996 | magic A magic string for obscuring password tag names. | |
997 | ||
998 | salt The salt for hashing the passphrase. | |
999 | ||
1000 | tag The master passphrase's tag, for the Pixie's benefit. | |
1001 | ||
494b719c MW |
1002 | Password entries are assigned labels of the form `$' || H(MAGIC || TAG); |
1003 | the corresponding value consists of a pair (TAG, PASSWD), prefixed with | |
1004 | 16-bit lengths, concatenated, padded to a multiple of 256 octets, and | |
1005 | encrypted using the stored keys. | |
d1c45f5c MW |
1006 | """ |
1007 | ||
4a35c9a7 | 1008 | def __init__(me, file, writep = False): |
d1c45f5c | 1009 | """ |
494b719c | 1010 | Initialize a PW object from the database in FILE. |
d1c45f5c | 1011 | |
494b719c MW |
1012 | If WRITEP is false (the default) then the database is opened read-only; |
1013 | if true then it may be written. Requests the database password from the | |
1014 | Pixie, which may cause interaction. | |
d1c45f5c MW |
1015 | """ |
1016 | ||
1017 | ## Open the database. | |
6baae405 | 1018 | me.db = StorageBackend.open(file, writep) |
d1c45f5c MW |
1019 | |
1020 | ## Find out what crypto to use. | |
494b719c MW |
1021 | c = _C.gcciphers[me.db.get_meta('cipher')] |
1022 | h = _C.gchashes[me.db.get_meta('hash')] | |
1023 | m = _C.gcmacs[me.db.get_meta('mac')] | |
d1c45f5c MW |
1024 | |
1025 | ## Request the passphrase and extract the master keys. | |
494b719c MW |
1026 | tag = me.db.get_meta('tag') |
1027 | ppk = PPK(_C.ppread(tag), c, h, m, me.db.get_meta('salt')) | |
43c09851 | 1028 | try: |
494b719c | 1029 | b = _C.ReadBuffer(ppk.decrypt(me.db.get_meta('key'))) |
43c09851 | 1030 | except DecryptError: |
1031 | _C.ppcancel(tag) | |
1032 | raise | |
9a7b948f MW |
1033 | me.ck = b.getblk16() |
1034 | me.mk = b.getblk16() | |
1c7419c9 | 1035 | if not b.endp: raise ValueError('trailing junk') |
d1c45f5c MW |
1036 | |
1037 | ## Set the key, and stash it and the tag-hashing secret. | |
43c09851 | 1038 | me.k = Crypto(c, h, m, me.ck, me.mk) |
494b719c | 1039 | me.magic = me.k.decrypt(me.db.get_meta('magic')) |
d1c45f5c | 1040 | |
09b8041d | 1041 | @classmethod |
6baae405 | 1042 | def create(cls, dbcls, file, tag, c, h, m): |
09b8041d | 1043 | """ |
6baae405 | 1044 | Create and initialize a new database FILE using StorageBackend DBCLS. |
09b8041d MW |
1045 | |
1046 | We want a GCipher subclass C, a GHash subclass H, and a GMAC subclass M; | |
1047 | and a Pixie passphrase TAG. | |
1048 | ||
1049 | This doesn't return a working object: it just creates the database file | |
1050 | and gets out of the way. | |
1051 | """ | |
1052 | ||
1053 | ## Set up the cryptography. | |
1054 | pp = _C.ppread(tag, _C.PMODE_VERIFY) | |
1055 | ppk = PPK(pp, c, h, m) | |
1056 | ck = _C.rand.block(c.keysz.default) | |
1057 | mk = _C.rand.block(c.keysz.default) | |
1058 | k = Crypto(c, h, m, ck, mk) | |
1059 | ||
1060 | ## Set up and initialize the database. | |
494b719c | 1061 | kct = ppk.encrypt(_C.WriteBuffer().putblk16(ck).putblk16(mk)) |
6baae405 | 1062 | with dbcls.create(file) as db: |
494b719c MW |
1063 | db.put_meta('tag', tag) |
1064 | db.put_meta('salt', ppk.salt) | |
1065 | db.put_meta('cipher', c.name) | |
1066 | db.put_meta('hash', h.name) | |
1067 | db.put_meta('mac', m.name) | |
1068 | db.put_meta('key', kct) | |
1069 | db.put_meta('magic', k.encrypt(_C.rand.block(h.hashsz))) | |
09b8041d | 1070 | |
43c09851 | 1071 | def keyxform(me, key): |
494b719c MW |
1072 | """Transform the KEY (actually a password tag) into a password label.""" |
1073 | return me.k.h().hash(me.magic).hash(key).done() | |
d1c45f5c | 1074 | |
43c09851 | 1075 | def changepp(me): |
d1c45f5c MW |
1076 | """ |
1077 | Change the database password. | |
1078 | ||
1079 | Requests the new password from the Pixie, which will probably cause | |
1080 | interaction. | |
1081 | """ | |
494b719c | 1082 | tag = me.db.get_meta('tag') |
43c09851 | 1083 | _C.ppcancel(tag) |
1084 | ppk = PPK(_C.ppread(tag, _C.PMODE_VERIFY), | |
d1c45f5c | 1085 | me.k.c.__class__, me.k.h, me.k.m.__class__) |
494b719c MW |
1086 | kct = ppk.encrypt(_C.WriteBuffer().putblk16(me.ck).putblk16(me.mk)) |
1087 | me.db.put_meta('key', kct) | |
1088 | me.db.put_meta('salt', ppk.salt) | |
d1c45f5c | 1089 | |
43c09851 | 1090 | def pack(me, key, value): |
494b719c | 1091 | """Pack the KEY and VALUE into a ciphertext, and return it.""" |
9a7b948f MW |
1092 | b = _C.WriteBuffer() |
1093 | b.putblk16(key).putblk16(value) | |
1094 | b.zero(((b.size + 255) & ~255) - b.size) | |
1095 | return me.k.encrypt(b) | |
d1c45f5c MW |
1096 | |
1097 | def unpack(me, ct): | |
1098 | """ | |
1099 | Unpack a ciphertext CT and return a (KEY, VALUE) pair. | |
1100 | ||
1101 | Might raise DecryptError, of course. | |
1102 | """ | |
9a7b948f MW |
1103 | b = _C.ReadBuffer(me.k.decrypt(ct)) |
1104 | key = b.getblk16() | |
1105 | value = b.getblk16() | |
43c09851 | 1106 | return key, value |
d1c45f5c MW |
1107 | |
1108 | ## Mapping protocol. | |
1109 | ||
43c09851 | 1110 | def __getitem__(me, key): |
494b719c MW |
1111 | """Return the password for the given KEY.""" |
1112 | try: return me.unpack(me.db.get_passwd(me.keyxform(key)))[1] | |
1c7419c9 | 1113 | except KeyError: raise KeyError(key) |
d1c45f5c | 1114 | |
43c09851 | 1115 | def __setitem__(me, key, value): |
494b719c MW |
1116 | """Associate the password VALUE with the KEY.""" |
1117 | me.db.put_passwd(me.keyxform(key), me.pack(key, value)) | |
d1c45f5c | 1118 | |
43c09851 | 1119 | def __delitem__(me, key): |
494b719c MW |
1120 | """Forget all about the KEY.""" |
1121 | try: me.db.del_passwd(me.keyxform(key)) | |
1c7419c9 | 1122 | except KeyError: raise KeyError(key) |
d1c45f5c | 1123 | |
43c09851 | 1124 | def __iter__(me): |
494b719c MW |
1125 | """Iterate over the known password tags.""" |
1126 | for _, pld in me.db.iter_passwds(): | |
1127 | yield me.unpack(pld)[0] | |
43c09851 | 1128 | |
5bf6e9f5 MW |
1129 | ## Context protocol. |
1130 | ||
1131 | def __enter__(me): | |
1132 | return me | |
1133 | def __exit__(me, excty, excval, exctb): | |
053c2659 | 1134 | me.db.close(excval is not None) |
5bf6e9f5 | 1135 | |
d1c45f5c | 1136 | ###----- That's all, folks -------------------------------------------------- |