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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 | ||
18a7521a MW |
53 | _M600 = int("600", 8) |
54 | _M700 = int("700", 8) | |
55 | ||
a41fd652 | 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) |
2aa7d3a9 | 205 | tag = pp + _NUL + salt |
43c09851 | 206 | Crypto.__init__(me, c, h, m, |
2aa7d3a9 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) | |
7f5c0c27 MW |
234 | try: name = me.NAME |
235 | except AttributeError: pass | |
236 | else: StorageBackend.register_concrete_subclass(me) | |
6baae405 | 237 | |
494b719c MW |
238 | class StorageBackend (object): |
239 | """ | |
1726ab40 MW |
240 | I provide basic protocol for password storage backends. |
241 | ||
242 | I'm an abstract class: you want one of my subclasses if you actually want | |
6baae405 MW |
243 | to do something useful. But I maintain a list of my subclasses and can |
244 | choose an appropriate one to open a database file you've found lying about. | |
494b719c MW |
245 | |
246 | Backends are responsible for storing and retrieving stuff, but not for the | |
247 | cryptographic details. Backends need to store two kinds of information: | |
248 | ||
249 | * metadata, consisting of a number of property names and their values; | |
250 | and | |
251 | ||
252 | * password mappings, consisting of a number of binary labels and | |
253 | payloads. | |
1726ab40 MW |
254 | |
255 | Backends need to implement the following ordinary methods. See the calling | |
256 | methods for details of the subclass responsibilities. | |
257 | ||
258 | BE._create(FILE) Create a new database in FILE; used by `create'. | |
259 | ||
260 | BE._open(FILE, WRITEP) | |
261 | Open the existing database FILE; used by `open'. | |
262 | ||
053c2659 MW |
263 | BE._close(ABRUPTP) Close the database, freeing up any resources. If |
264 | ABRUPTP then don't try to commit changes. | |
1726ab40 MW |
265 | |
266 | BE._get_meta(NAME, DEFAULT) | |
267 | Return the value of the metadata item with the given | |
268 | NAME, or DEFAULT if it doesn't exist; used by | |
269 | `get_meta'. | |
270 | ||
271 | BE._put_meta(NAME, VALUE) | |
272 | Set the VALUE of the metadata item with the given | |
273 | NAME, creating one if necessary; used by `put_meta'. | |
274 | ||
275 | BE._del_meta(NAME) Forget the metadata item with the given NAME; raise | |
276 | `KeyError' if there is no such item; used by | |
277 | `del_meta'. | |
278 | ||
279 | BE._iter_meta() Return an iterator over the metadata (NAME, VALUE) | |
280 | pairs; used by `iter_meta'. | |
281 | ||
282 | BE._get_passwd(LABEL) | |
283 | Return the password payload stored with the (binary) | |
284 | LABEL; used by `get_passwd'. | |
285 | ||
286 | BE._put_passwd(LABEL, PAYLOAD) | |
287 | Associate the (binary) PAYLOAD with the LABEL, | |
288 | forgetting any previous payload for that LABEL; used | |
289 | by `put_passwd'. | |
290 | ||
291 | BE._del_passwd(LABEL) Forget the password record with the given LABEL; used | |
292 | by `_del_passwd'. | |
293 | ||
294 | BE._iter_passwds() Return an iterator over the password (LABEL, PAYLOAD) | |
295 | pairs; used by `iter_passwds'. | |
6baae405 MW |
296 | |
297 | Also, concrete subclasses should define the following class attributes. | |
298 | ||
299 | NAME The name of the backend, so that the user can select | |
300 | it when creating a new database. | |
301 | ||
302 | PRIO An integer priority: backends are tried in decreasing | |
303 | priority order when opening an existing database. | |
494b719c MW |
304 | """ |
305 | ||
6baae405 | 306 | __metaclass__ = StorageBackendClass |
6baae405 MW |
307 | PRIO = 10 |
308 | ||
309 | ## The registry of subclasses. | |
310 | CLASSES = {} | |
311 | ||
494b719c MW |
312 | FAIL = ['FAIL'] |
313 | ||
6baae405 MW |
314 | @staticmethod |
315 | def register_concrete_subclass(sub): | |
316 | """Register a concrete subclass, so that `open' can try it.""" | |
317 | StorageBackend.CLASSES[sub.NAME] = sub | |
318 | ||
319 | @staticmethod | |
320 | def byname(name): | |
321 | """ | |
322 | Return the concrete subclass with the given NAME. | |
323 | ||
324 | Raise `KeyError' if the name isn't found. | |
325 | """ | |
326 | return StorageBackend.CLASSES[name] | |
327 | ||
328 | @staticmethod | |
329 | def classes(): | |
330 | """Return an iterator over the concrete subclasses.""" | |
82910fd3 | 331 | return _itervalues(StorageBackend.CLASSES) |
6baae405 MW |
332 | |
333 | @staticmethod | |
334 | def open(file, writep = False): | |
335 | """Open a database FILE, using some appropriate backend.""" | |
336 | _OS.stat(file) | |
337 | for cls in sorted(StorageBackend.CLASSES.values(), reverse = True, | |
338 | key = lambda cls: cls.PRIO): | |
339 | try: return cls(file, writep) | |
340 | except StorageBackendRefusal: pass | |
341 | raise StorageBackendRefusal | |
494b719c MW |
342 | |
343 | @classmethod | |
344 | def create(cls, file): | |
1726ab40 MW |
345 | """ |
346 | Create a new database in the named FILE, using this backend. | |
347 | ||
348 | Subclasses must implement the `_create' instance method. | |
349 | """ | |
494b719c | 350 | return cls(writep = True, _magic = lambda me: me._create(file)) |
494b719c MW |
351 | |
352 | def __init__(me, file = None, writep = False, _magic = None, *args, **kw): | |
353 | """ | |
354 | Main constructor. | |
1726ab40 MW |
355 | |
356 | Subclasses are not, in general, expected to override this: there's a | |
357 | somewhat hairy protocol between the constructor and some of the class | |
358 | methods. Instead, the main hook for customization is the subclass's | |
359 | `_open' method, which is invoked in the usual case. | |
494b719c MW |
360 | """ |
361 | super(StorageBackend, me).__init__(*args, **kw) | |
e3b6c0d3 | 362 | if me.NAME is None: raise ValueError('abstract class') |
494b719c | 363 | if _magic is not None: _magic(me) |
e3b6c0d3 | 364 | elif file is None: raise ValueError('missing file parameter') |
1726ab40 | 365 | else: me._open(file, writep) |
494b719c MW |
366 | me._writep = writep |
367 | me._livep = True | |
368 | ||
053c2659 | 369 | def close(me, abruptp = False): |
494b719c MW |
370 | """ |
371 | Close the database. | |
372 | ||
373 | It is harmless to attempt to close a database which has been closed | |
1726ab40 | 374 | already. Calls the subclass's `_close' method. |
494b719c MW |
375 | """ |
376 | if me._livep: | |
377 | me._livep = False | |
053c2659 | 378 | me._close(abruptp) |
494b719c MW |
379 | |
380 | ## Utilities. | |
381 | ||
382 | def _check_live(me): | |
383 | """Raise an error if the receiver has been closed.""" | |
e3b6c0d3 | 384 | if not me._livep: raise ValueError('database is closed') |
494b719c MW |
385 | |
386 | def _check_write(me): | |
387 | """Raise an error if the receiver is not open for writing.""" | |
388 | me._check_live() | |
e3b6c0d3 | 389 | if not me._writep: raise ValueError('database is read-only') |
494b719c MW |
390 | |
391 | def _check_meta_name(me, name): | |
392 | """ | |
393 | Raise an error unless NAME is a valid name for a metadata item. | |
394 | ||
395 | Metadata names may not start with `$': such names are reserved for | |
396 | password storage. | |
397 | """ | |
398 | if name.startswith('$'): | |
e3b6c0d3 | 399 | raise ValueError("invalid metadata key `%s'" % name) |
494b719c MW |
400 | |
401 | ## Context protocol. | |
402 | ||
403 | def __enter__(me): | |
404 | """Context protocol: make sure the database is closed on exit.""" | |
405 | return me | |
406 | def __exit__(me, exctype, excvalue, exctb): | |
407 | """Context protocol: see `__enter__'.""" | |
053c2659 | 408 | me.close(excvalue is not None) |
494b719c MW |
409 | |
410 | ## Metadata. | |
411 | ||
412 | def get_meta(me, name, default = FAIL): | |
413 | """ | |
414 | Fetch the value for the metadata item NAME. | |
415 | ||
416 | If no such item exists, then return DEFAULT if that was set; otherwise | |
417 | raise a `KeyError'. | |
1726ab40 MW |
418 | |
419 | This calls the subclass's `_get_meta' method, which should return the | |
420 | requested item or return the given DEFAULT value. It may assume that the | |
421 | name is valid and the database is open. | |
494b719c MW |
422 | """ |
423 | me._check_meta_name(name) | |
424 | me._check_live() | |
1726ab40 | 425 | value = me._get_meta(name, default) |
e3b6c0d3 | 426 | if value is StorageBackend.FAIL: raise KeyError(name) |
494b719c MW |
427 | return value |
428 | ||
429 | def put_meta(me, name, value): | |
1726ab40 MW |
430 | """ |
431 | Store VALUE in the metadata item called NAME. | |
432 | ||
433 | This calls the subclass's `_put_meta' method, which may assume that the | |
434 | name is valid and the database is open for writing. | |
435 | """ | |
494b719c MW |
436 | me._check_meta_name(name) |
437 | me._check_write() | |
1726ab40 | 438 | me._put_meta(name, value) |
494b719c MW |
439 | |
440 | def del_meta(me, name): | |
1726ab40 MW |
441 | """ |
442 | Forget about the metadata item with the given NAME. | |
443 | ||
444 | This calls the subclass's `_del_meta' method, which may assume that the | |
445 | name is valid and the database is open for writing. | |
446 | """ | |
494b719c MW |
447 | me._check_meta_name(name) |
448 | me._check_write() | |
1726ab40 | 449 | me._del_meta(name) |
494b719c MW |
450 | |
451 | def iter_meta(me): | |
1726ab40 MW |
452 | """ |
453 | Return an iterator over the name/value metadata items. | |
494b719c | 454 | |
1726ab40 MW |
455 | This calls the subclass's `_iter_meta' method, which may assume that the |
456 | database is open. | |
457 | """ | |
458 | me._check_live() | |
459 | return me._iter_meta() | |
494b719c MW |
460 | |
461 | def get_passwd(me, label): | |
462 | """ | |
463 | Fetch and return the payload stored with the (opaque, binary) LABEL. | |
464 | ||
465 | If there is no such payload then raise `KeyError'. | |
1726ab40 MW |
466 | |
467 | This calls the subclass's `_get_passwd' method, which may assume that the | |
468 | database is open. | |
494b719c MW |
469 | """ |
470 | me._check_live() | |
1726ab40 | 471 | return me._get_passwd(label) |
494b719c MW |
472 | |
473 | def put_passwd(me, label, payload): | |
474 | """ | |
475 | Associate the (opaque, binary) PAYLOAD with the (opaque, binary) LABEL. | |
476 | ||
477 | Any previous payload for LABEL is forgotten. | |
1726ab40 MW |
478 | |
479 | This calls the subclass's `_put_passwd' method, which may assume that the | |
480 | database is open for writing. | |
494b719c MW |
481 | """ |
482 | me._check_write() | |
1726ab40 | 483 | me._put_passwd(label, payload) |
494b719c MW |
484 | |
485 | def del_passwd(me, label): | |
486 | """ | |
487 | Forget any PAYLOAD associated with the (opaque, binary) LABEL. | |
488 | ||
489 | If there is no such payload then raise `KeyError'. | |
1726ab40 MW |
490 | |
491 | This calls the subclass's `_del_passwd' method, which may assume that the | |
492 | database is open for writing. | |
494b719c MW |
493 | """ |
494 | me._check_write() | |
1d93191e | 495 | me._del_passwd(label) |
494b719c MW |
496 | |
497 | def iter_passwds(me): | |
1726ab40 MW |
498 | """ |
499 | Return an iterator over the stored password label/payload pairs. | |
500 | ||
501 | This calls the subclass's `_iter_passwds' method, which may assume that | |
502 | the database is open. | |
503 | """ | |
494b719c | 504 | me._check_live() |
1726ab40 MW |
505 | return me._iter_passwds() |
506 | ||
8501dc39 MW |
507 | try: import gdbm as _G |
508 | except ImportError: pass | |
509 | else: | |
510 | class GDBMStorageBackend (StorageBackend): | |
511 | """ | |
512 | My instances store password data in a GDBM database. | |
1726ab40 | 513 | |
8501dc39 MW |
514 | Metadata and password entries are mixed into the same database. The key |
515 | for a metadata item is simply its name; the key for a password entry is | |
516 | the entry's label prefixed by `$', since we're guaranteed that no | |
517 | metadata item name begins with `$'. | |
518 | """ | |
1726ab40 | 519 | |
8501dc39 | 520 | NAME = 'gdbm' |
6baae405 | 521 | |
8501dc39 MW |
522 | def _open(me, file, writep): |
523 | try: me._db = _G.open(file, writep and 'w' or 'r') | |
a41fd652 | 524 | except _G.error: raise StorageBackendRefusal(_excval()) |
1726ab40 | 525 | |
8501dc39 | 526 | def _create(me, file): |
18a7521a | 527 | me._db = _G.open(file, 'n', _M600) |
1726ab40 | 528 | |
8501dc39 MW |
529 | def _close(me, abruptp): |
530 | me._db.close() | |
531 | me._db = None | |
1726ab40 | 532 | |
8501dc39 MW |
533 | def _get_meta(me, name, default): |
534 | try: return me._db[name] | |
535 | except KeyError: return default | |
1726ab40 | 536 | |
8501dc39 MW |
537 | def _put_meta(me, name, value): |
538 | me._db[name] = value | |
1726ab40 | 539 | |
8501dc39 MW |
540 | def _del_meta(me, name): |
541 | del me._db[name] | |
1726ab40 | 542 | |
8501dc39 MW |
543 | def _iter_meta(me): |
544 | k = me._db.firstkey() | |
545 | while k is not None: | |
546 | if not k.startswith('$'): yield k, me._db[k] | |
547 | k = me._db.nextkey(k) | |
1726ab40 | 548 | |
8501dc39 MW |
549 | def _get_passwd(me, label): |
550 | return me._db['$' + label] | |
1726ab40 | 551 | |
8501dc39 MW |
552 | def _put_passwd(me, label, payload): |
553 | me._db['$' + label] = payload | |
1726ab40 | 554 | |
8501dc39 MW |
555 | def _del_passwd(me, label): |
556 | del me._db['$' + label] | |
1726ab40 | 557 | |
8501dc39 MW |
558 | def _iter_passwds(me): |
559 | k = me._db.firstkey() | |
560 | while k is not None: | |
561 | if k.startswith('$'): yield k[1:], me._db[k] | |
562 | k = me._db.nextkey(k) | |
494b719c | 563 | |
e92f9aa2 MW |
564 | try: import sqlite3 as _Q |
565 | except ImportError: pass | |
566 | else: | |
567 | class SQLiteStorageBackend (StorageBackend): | |
568 | """ | |
569 | I represent a password database stored in SQLite. | |
570 | ||
571 | Metadata and password items are stored in separate tables, so there's no | |
572 | conflict. Some additional metadata is stored in the `meta' table, with | |
573 | names beginning with `$' so as not to conflict with clients: | |
574 | ||
575 | $version The schema version of the table. | |
576 | """ | |
577 | ||
578 | NAME = 'sqlite' | |
579 | VERSION = 0 | |
580 | ||
581 | def _open(me, file, writep): | |
582 | try: | |
583 | me._db = _Q.connect(file) | |
584 | ver = me._query_scalar( | |
585 | "SELECT value FROM meta WHERE name = '$version'", | |
586 | "version check") | |
a41fd652 MW |
587 | except (_Q.DatabaseError, _Q.OperationalError): |
588 | raise StorageBackendRefusal(_excval()) | |
e3b6c0d3 | 589 | if ver is None: raise ValueError('database broken (missing $version)') |
e92f9aa2 | 590 | elif ver < me.VERSION: me._upgrade(ver) |
e3b6c0d3 MW |
591 | elif ver > me.VERSION: raise ValueError \ |
592 | ('unknown database schema version (%d > %d)' % (ver, me.VERSION)) | |
e92f9aa2 MW |
593 | |
594 | def _create(me, file): | |
18a7521a | 595 | fd = _OS.open(file, _OS.O_WRONLY | _OS.O_CREAT | _OS.O_EXCL, _M600) |
e92f9aa2 MW |
596 | _OS.close(fd) |
597 | try: | |
598 | me._db = _Q.connect(file) | |
599 | c = me._db.cursor() | |
600 | c.execute(""" | |
601 | CREATE TABLE meta ( | |
602 | name TEXT PRIMARY KEY NOT NULL, | |
603 | value BLOB NOT NULL); | |
604 | """) | |
605 | c.execute(""" | |
606 | CREATE TABLE passwd ( | |
607 | label BLOB PRIMARY KEY NOT NULL, | |
608 | payload BLOB NOT NULL); | |
609 | """) | |
610 | c.execute(""" | |
611 | INSERT INTO meta (name, value) VALUES ('$version', ?); | |
612 | """, [me.VERSION]) | |
613 | except: | |
614 | try: _OS.unlink(file) | |
615 | except OSError: pass | |
616 | raise | |
617 | ||
618 | def _upgrade(me, ver): | |
619 | """Upgrade the database from schema version VER.""" | |
620 | assert False, 'how embarrassing' | |
621 | ||
622 | def _close(me, abruptp): | |
623 | if not abruptp: me._db.commit() | |
624 | me._db.close() | |
625 | me._db = None | |
626 | ||
627 | def _fetch_scalar(me, c, what, default = None): | |
628 | try: row = next(c) | |
629 | except StopIteration: val = default | |
630 | else: val, = row | |
631 | try: row = next(c) | |
632 | except StopIteration: pass | |
e3b6c0d3 | 633 | else: raise ValueError('multiple matching records for %s' % what) |
e92f9aa2 MW |
634 | return val |
635 | ||
636 | def _query_scalar(me, query, what, default = None, args = []): | |
637 | c = me._db.cursor() | |
638 | c.execute(query, args) | |
639 | return me._fetch_scalar(c, what, default) | |
640 | ||
641 | def _get_meta(me, name, default): | |
642 | v = me._query_scalar("SELECT value FROM meta WHERE name = ?", | |
643 | "metadata item `%s'" % name, | |
644 | default = default, args = [name]) | |
645 | if v is default: return v | |
646 | else: return str(v) | |
647 | ||
648 | def _put_meta(me, name, value): | |
649 | c = me._db.cursor() | |
650 | c.execute("INSERT OR REPLACE INTO meta (name, value) VALUES (?, ?)", | |
651 | [name, buffer(value)]) | |
652 | ||
653 | def _del_meta(me, name): | |
654 | c = me._db.cursor() | |
655 | c.execute("DELETE FROM meta WHERE name = ?", [name]) | |
e3b6c0d3 | 656 | if not c.rowcount: raise KeyError(name) |
e92f9aa2 MW |
657 | |
658 | def _iter_meta(me): | |
659 | c = me._db.cursor() | |
660 | c.execute("SELECT name, value FROM meta WHERE name NOT LIKE '$%'") | |
661 | for k, v in c: yield k, str(v) | |
662 | ||
663 | def _get_passwd(me, label): | |
664 | pld = me._query_scalar("SELECT payload FROM passwd WHERE label = ?", | |
665 | "password", default = None, | |
666 | args = [buffer(label)]) | |
e3b6c0d3 | 667 | if pld is None: raise KeyError(label) |
e92f9aa2 MW |
668 | return str(pld) |
669 | ||
670 | def _put_passwd(me, label, payload): | |
671 | c = me._db.cursor() | |
672 | c.execute("INSERT OR REPLACE INTO passwd (label, payload) " | |
673 | "VALUES (?, ?)", | |
674 | [buffer(label), buffer(payload)]) | |
675 | ||
676 | def _del_passwd(me, label): | |
677 | c = me._db.cursor() | |
678 | c.execute("DELETE FROM passwd WHERE label = ?", [label]) | |
e3b6c0d3 | 679 | if not c.rowcount: raise KeyError(label) |
e92f9aa2 MW |
680 | |
681 | def _iter_passwds(me): | |
682 | c = me._db.cursor() | |
683 | c.execute("SELECT label, payload FROM passwd") | |
684 | for k, v in c: yield str(k), str(v) | |
685 | ||
af861fb7 MW |
686 | class PlainTextBackend (StorageBackend): |
687 | """ | |
688 | I'm a utility base class for storage backends which use plain text files. | |
689 | ||
690 | I provide subclasses with the following capabilities. | |
691 | ||
692 | * Creating files, with given modes, optionally ensuring that the file | |
693 | doesn't exist already. | |
694 | ||
695 | * Parsing flat text files, checking leading magic, skipping comments, and | |
696 | providing standard encodings of troublesome characters and binary | |
697 | strings in metadata and password records. See below. | |
698 | ||
699 | * Maintenance of metadata and password records in in-memory dictionaries, | |
700 | with ready implementations of the necessary StorageBackend subclass | |
701 | responsibility methods. (Subclasses can override these if they want to | |
702 | make different arrangements.) | |
703 | ||
704 | Metadata records are written with an optional prefix string chosen by the | |
705 | caller, followed by a `NAME=VALUE' pair. The NAME is form-urlencoded and | |
706 | prefixed with `!' if it contains strange characters; the VALUE is base64- | |
707 | encoded (without the pointless trailing `=' padding) and prefixed with `?' | |
708 | if necessary. | |
709 | ||
710 | Password records are written with an optional prefix string chosen by the | |
711 | caller, followed by a LABEL=PAYLOAD pair, both of which are base64-encoded | |
712 | (without padding). | |
713 | ||
714 | The following attributes are available for subclasses: | |
715 | ||
716 | _meta Dictionary mapping metadata item names to their values. | |
717 | Populated by `_parse_meta' and managed by `_get_meta' and | |
718 | friends. | |
719 | ||
720 | _pw Dictionary mapping password labels to encrypted payloads. | |
721 | Populated by `_parse_passwd' and managed by `_get_passwd' and | |
722 | friends. | |
723 | ||
724 | _dirtyp Boolean: set if either of the dictionaries has been modified. | |
725 | """ | |
726 | ||
727 | def __init__(me, *args, **kw): | |
728 | """ | |
729 | Hook for initialization. | |
730 | ||
731 | Sets up the published instance attributes. | |
732 | """ | |
733 | me._meta = {} | |
734 | me._pw = {} | |
735 | me._dirtyp = False | |
736 | super(PlainTextBackend, me).__init__(*args, **kw) | |
737 | ||
18a7521a | 738 | def _create_file(me, file, mode = _M600, freshp = False): |
af861fb7 MW |
739 | """ |
740 | Make sure FILE exists, creating it with the given MODE if necessary. | |
741 | ||
742 | If FRESHP is true, then make sure the file did not exist previously. | |
743 | Return a file object for the newly created file. | |
744 | """ | |
745 | flags = _OS.O_CREAT | _OS.O_WRONLY | |
746 | if freshp: flags |= _OS.O_EXCL | |
747 | else: flags |= _OS.O_TRUNC | |
748 | fd = _OS.open(file, flags, mode) | |
749 | return _OS.fdopen(fd, 'w') | |
750 | ||
751 | def _mark_dirty(me): | |
752 | """ | |
753 | Set the `_dirtyp' flag. | |
754 | ||
755 | Subclasses might find it useful to intercept this method. | |
756 | """ | |
757 | me._dirtyp = True | |
758 | ||
759 | def _eqsplit(me, line): | |
760 | """ | |
761 | Extract the KEY, VALUE pair from a LINE of the form `KEY=VALUE'. | |
762 | ||
763 | Raise `ValueError' if there is no `=' in the LINE. | |
764 | """ | |
765 | eq = line.index('=') | |
766 | return line[:eq], line[eq + 1:] | |
767 | ||
768 | def _parse_file(me, file, magic = None): | |
769 | """ | |
770 | Parse a FILE. | |
771 | ||
772 | Specifically: | |
773 | ||
774 | * Raise `StorageBackendRefusal' if that the first line doesn't match | |
775 | MAGIC (if provided). MAGIC should not contain the terminating | |
776 | newline. | |
777 | ||
778 | * Ignore comments (beginning `#') and blank lines. | |
779 | ||
780 | * Call `_parse_line' (provided by the subclass) for other lines. | |
781 | """ | |
782 | with open(file, 'r') as f: | |
783 | if magic is not None: | |
784 | if f.readline().rstrip('\n') != magic: raise StorageBackendRefusal | |
785 | for line in f: | |
786 | line = line.rstrip('\n') | |
787 | if not line or line.startswith('#'): continue | |
788 | me._parse_line(line) | |
789 | ||
18a7521a | 790 | def _write_file(me, file, writebody, mode = _M600, magic = None): |
af861fb7 MW |
791 | """ |
792 | Update FILE atomically. | |
793 | ||
794 | The newly created file will have the given MODE. If MAGIC is given, then | |
795 | write that as the first line. Calls WRITEBODY(F) to write the main body | |
796 | of the file where F is a file object for the new file. | |
797 | """ | |
798 | new = file + '.new' | |
799 | with me._create_file(new, mode) as f: | |
800 | if magic is not None: f.write(magic + '\n') | |
801 | writebody(f) | |
802 | _OS.rename(new, file) | |
803 | ||
804 | def _parse_meta(me, line): | |
805 | """Parse LINE as a metadata NAME=VALUE pair, and updates `_meta'.""" | |
806 | k, v = me._eqsplit(line) | |
807 | me._meta[_dec_metaname(k)] = _dec_metaval(v) | |
808 | ||
809 | def _write_meta(me, f, prefix = ''): | |
810 | """Write the metadata records to F, each with the given PREFIX.""" | |
811 | f.write('\n## Metadata.\n') | |
82910fd3 | 812 | for k, v in _iteritems(me._meta): |
af861fb7 MW |
813 | f.write('%s%s=%s\n' % (prefix, _enc_metaname(k), _enc_metaval(v))) |
814 | ||
815 | def _get_meta(me, name, default): | |
816 | return me._meta.get(name, default) | |
817 | def _put_meta(me, name, value): | |
818 | me._mark_dirty() | |
819 | me._meta[name] = value | |
820 | def _del_meta(me, name): | |
821 | me._mark_dirty() | |
822 | del me._meta[name] | |
823 | def _iter_meta(me): | |
82910fd3 | 824 | return _iteritems(me._meta) |
af861fb7 MW |
825 | |
826 | def _parse_passwd(me, line): | |
827 | """Parse LINE as a password LABEL=PAYLOAD pair, and updates `_pw'.""" | |
828 | k, v = me._eqsplit(line) | |
829 | me._pw[_unb64(k)] = _unb64(v) | |
830 | ||
831 | def _write_passwd(me, f, prefix = ''): | |
832 | """Write the password records to F, each with the given PREFIX.""" | |
833 | f.write('\n## Password data.\n') | |
82910fd3 | 834 | for k, v in _iteritems(me._pw): |
af861fb7 MW |
835 | f.write('%s%s=%s\n' % (prefix, _b64(k), _b64(v))) |
836 | ||
837 | def _get_passwd(me, label): | |
838 | return me._pw[str(label)] | |
839 | def _put_passwd(me, label, payload): | |
840 | me._mark_dirty() | |
841 | me._pw[str(label)] = payload | |
842 | def _del_passwd(me, label): | |
843 | me._mark_dirty() | |
844 | del me._pw[str(label)] | |
845 | def _iter_passwds(me): | |
82910fd3 | 846 | return _iteritems(me._pw) |
af861fb7 MW |
847 | |
848 | class FlatFileStorageBackend (PlainTextBackend): | |
849 | """ | |
850 | I maintain a password database in a plain text file. | |
851 | ||
852 | The text file consists of lines, as follows. | |
853 | ||
854 | * Empty lines, and lines beginning with `#' (in the leftmost column only) | |
855 | are ignored. | |
856 | ||
857 | * Lines of the form `$LABEL=PAYLOAD' store password data. Both LABEL and | |
858 | PAYLOAD are base64-encoded, without `=' padding. | |
859 | ||
860 | * Lines of the form `NAME=VALUE' store metadata. If the NAME contains | |
861 | characters other than alphanumerics, hyphens, underscores, and colons, | |
862 | then it is form-urlencoded, and prefixed wth `!'. If the VALUE | |
863 | contains such characters, then it is base64-encoded, without `=' | |
864 | padding, and prefixed with `?'. | |
865 | ||
866 | * Other lines are erroneous. | |
867 | ||
868 | The file is rewritten from scratch when it's changed: any existing | |
869 | commentary is lost, and items may be reordered. There is no file locking, | |
870 | but the file is updated atomically, by renaming. | |
871 | ||
872 | It is expected that the FlatFileStorageBackend is used mostly for | |
873 | diagnostics and transfer, rather than for a live system. | |
874 | """ | |
875 | ||
876 | NAME = 'flat' | |
877 | PRIO = 0 | |
878 | MAGIC = '### pwsafe password database' | |
879 | ||
880 | def _open(me, file, writep): | |
881 | if not _OS.path.isfile(file): raise StorageBackendRefusal | |
882 | me._parse_file(file, magic = me.MAGIC) | |
883 | def _parse_line(me, line): | |
884 | if line.startswith('$'): me._parse_passwd(line[1:]) | |
885 | else: me._parse_meta(line) | |
886 | ||
887 | def _create(me, file): | |
888 | with me._create_file(file, freshp = True) as f: pass | |
889 | me._file = file | |
890 | me._mark_dirty() | |
891 | ||
892 | def _close(me, abruptp): | |
893 | if not abruptp and me._dirtyp: | |
894 | me._write_file(me._file, me._write_body, magic = me.MAGIC) | |
895 | ||
896 | def _write_body(me, f): | |
897 | me._write_meta(f) | |
898 | me._write_passwd(f, '$') | |
899 | ||
b61e9efe MW |
900 | class DirectoryStorageBackend (PlainTextBackend): |
901 | """ | |
902 | I maintain a password database in a directory, with one file per password. | |
903 | ||
904 | This makes password databases easy to maintain in a revision-control system | |
905 | such as Git. | |
906 | ||
907 | The directory is structured as follows. | |
908 | ||
909 | dir/meta Contains metadata, similar to the `FlatFileBackend'. | |
910 | ||
911 | dir/pw/LABEL Contains the (raw binary) payload for the given password | |
912 | LABEL (base64-encoded, without the useless `=' padding, and | |
913 | with `/' replaced by `.'). | |
914 | ||
915 | dir/tmp/ Contains temporary files used by the implementation. | |
916 | """ | |
917 | ||
918 | NAME = 'dir' | |
919 | METAMAGIC = '### pwsafe password directory metadata' | |
920 | ||
921 | def _open(me, file, writep): | |
922 | if not _OS.path.isdir(file) or \ | |
923 | not _OS.path.isdir(_OS.path.join(file, 'pw')) or \ | |
924 | not _OS.path.isdir(_OS.path.join(file, 'tmp')) or \ | |
925 | not _OS.path.isfile(_OS.path.join(file, 'meta')): | |
926 | raise StorageBackendRefusal | |
927 | me._dir = file | |
928 | me._parse_file(_OS.path.join(file, 'meta'), magic = me.METAMAGIC) | |
929 | def _parse_line(me, line): | |
930 | me._parse_meta(line) | |
931 | ||
932 | def _create(me, file): | |
18a7521a MW |
933 | _OS.mkdir(file, _M700) |
934 | _OS.mkdir(_OS.path.join(file, 'pw'), _M700) | |
935 | _OS.mkdir(_OS.path.join(file, 'tmp'), _M700) | |
b61e9efe MW |
936 | me._mark_dirty() |
937 | me._dir = file | |
938 | ||
939 | def _close(me, abruptp): | |
940 | if not abruptp and me._dirtyp: | |
941 | me._write_file(_OS.path.join(me._dir, 'meta'), | |
942 | me._write_meta, magic = me.METAMAGIC) | |
943 | ||
944 | def _pwfile(me, label, dir = 'pw'): | |
945 | return _OS.path.join(me._dir, dir, _b64(label).replace('/', '.')) | |
946 | def _get_passwd(me, label): | |
947 | try: | |
948 | f = open(me._pwfile(label), 'rb') | |
a41fd652 MW |
949 | except (OSError, IOError): |
950 | if _excval().errno == _E.ENOENT: raise KeyError(label) | |
b61e9efe MW |
951 | else: raise |
952 | with f: return f.read() | |
953 | def _put_passwd(me, label, payload): | |
954 | new = me._pwfile(label, 'tmp') | |
18a7521a | 955 | fd = _OS.open(new, _OS.O_WRONLY | _OS.O_CREAT | _OS.O_TRUNC, _M600) |
b61e9efe MW |
956 | _OS.close(fd) |
957 | with open(new, 'wb') as f: f.write(payload) | |
958 | _OS.rename(new, me._pwfile(label)) | |
959 | def _del_passwd(me, label): | |
960 | try: | |
961 | _OS.remove(me._pwfile(label)) | |
a41fd652 MW |
962 | except (OSError, IOError): |
963 | if _excval().errno == _E.ENOENT: raise KeyError(label) | |
b61e9efe MW |
964 | else: raise |
965 | def _iter_passwds(me): | |
966 | pw = _OS.path.join(me._dir, 'pw') | |
967 | for i in _OS.listdir(pw): | |
968 | with open(_OS.path.join(pw, i), 'rb') as f: pld = f.read() | |
969 | yield _unb64(i.replace('.', '/')), pld | |
970 | ||
494b719c | 971 | ###-------------------------------------------------------------------------- |
d1c45f5c | 972 | ### Password storage. |
43c09851 | 973 | |
43c09851 | 974 | class PW (object): |
d1c45f5c MW |
975 | """ |
976 | I represent a secure (ish) password store. | |
977 | ||
978 | I can store short secrets, associated with textual names, in a way which | |
979 | doesn't leak too much information about them. | |
980 | ||
2119e334 | 981 | I implement (some of) the Python mapping protocol. |
d1c45f5c | 982 | |
494b719c MW |
983 | I keep track of everything using a StorageBackend object. This contains |
984 | password entries, identified by cryptographic labels, and a number of | |
985 | metadata items. | |
d1c45f5c MW |
986 | |
987 | cipher Names the Catacomb cipher selected. | |
988 | ||
989 | hash Names the Catacomb hash function selected. | |
990 | ||
991 | key Cipher and MAC keys, each prefixed by a 16-bit big-endian | |
992 | length and concatenated, encrypted using the master | |
993 | passphrase. | |
994 | ||
995 | mac Names the Catacomb message authentication code selected. | |
996 | ||
997 | magic A magic string for obscuring password tag names. | |
998 | ||
999 | salt The salt for hashing the passphrase. | |
1000 | ||
1001 | tag The master passphrase's tag, for the Pixie's benefit. | |
1002 | ||
494b719c MW |
1003 | Password entries are assigned labels of the form `$' || H(MAGIC || TAG); |
1004 | the corresponding value consists of a pair (TAG, PASSWD), prefixed with | |
1005 | 16-bit lengths, concatenated, padded to a multiple of 256 octets, and | |
1006 | encrypted using the stored keys. | |
d1c45f5c MW |
1007 | """ |
1008 | ||
4a35c9a7 | 1009 | def __init__(me, file, writep = False): |
d1c45f5c | 1010 | """ |
494b719c | 1011 | Initialize a PW object from the database in FILE. |
d1c45f5c | 1012 | |
494b719c MW |
1013 | If WRITEP is false (the default) then the database is opened read-only; |
1014 | if true then it may be written. Requests the database password from the | |
1015 | Pixie, which may cause interaction. | |
d1c45f5c MW |
1016 | """ |
1017 | ||
1018 | ## Open the database. | |
6baae405 | 1019 | me.db = StorageBackend.open(file, writep) |
d1c45f5c MW |
1020 | |
1021 | ## Find out what crypto to use. | |
494b719c MW |
1022 | c = _C.gcciphers[me.db.get_meta('cipher')] |
1023 | h = _C.gchashes[me.db.get_meta('hash')] | |
1024 | m = _C.gcmacs[me.db.get_meta('mac')] | |
d1c45f5c MW |
1025 | |
1026 | ## Request the passphrase and extract the master keys. | |
494b719c MW |
1027 | tag = me.db.get_meta('tag') |
1028 | ppk = PPK(_C.ppread(tag), c, h, m, me.db.get_meta('salt')) | |
43c09851 | 1029 | try: |
494b719c | 1030 | b = _C.ReadBuffer(ppk.decrypt(me.db.get_meta('key'))) |
43c09851 | 1031 | except DecryptError: |
1032 | _C.ppcancel(tag) | |
1033 | raise | |
9a7b948f MW |
1034 | me.ck = b.getblk16() |
1035 | me.mk = b.getblk16() | |
e3b6c0d3 | 1036 | if not b.endp: raise ValueError('trailing junk') |
d1c45f5c MW |
1037 | |
1038 | ## Set the key, and stash it and the tag-hashing secret. | |
43c09851 | 1039 | me.k = Crypto(c, h, m, me.ck, me.mk) |
494b719c | 1040 | me.magic = me.k.decrypt(me.db.get_meta('magic')) |
d1c45f5c | 1041 | |
09b8041d | 1042 | @classmethod |
6baae405 | 1043 | def create(cls, dbcls, file, tag, c, h, m): |
09b8041d | 1044 | """ |
6baae405 | 1045 | Create and initialize a new database FILE using StorageBackend DBCLS. |
09b8041d MW |
1046 | |
1047 | We want a GCipher subclass C, a GHash subclass H, and a GMAC subclass M; | |
1048 | and a Pixie passphrase TAG. | |
1049 | ||
1050 | This doesn't return a working object: it just creates the database file | |
1051 | and gets out of the way. | |
1052 | """ | |
1053 | ||
1054 | ## Set up the cryptography. | |
1055 | pp = _C.ppread(tag, _C.PMODE_VERIFY) | |
1056 | ppk = PPK(pp, c, h, m) | |
1057 | ck = _C.rand.block(c.keysz.default) | |
1058 | mk = _C.rand.block(c.keysz.default) | |
1059 | k = Crypto(c, h, m, ck, mk) | |
1060 | ||
1061 | ## Set up and initialize the database. | |
494b719c | 1062 | kct = ppk.encrypt(_C.WriteBuffer().putblk16(ck).putblk16(mk)) |
6baae405 | 1063 | with dbcls.create(file) as db: |
494b719c MW |
1064 | db.put_meta('tag', tag) |
1065 | db.put_meta('salt', ppk.salt) | |
1066 | db.put_meta('cipher', c.name) | |
1067 | db.put_meta('hash', h.name) | |
1068 | db.put_meta('mac', m.name) | |
1069 | db.put_meta('key', kct) | |
1070 | db.put_meta('magic', k.encrypt(_C.rand.block(h.hashsz))) | |
09b8041d | 1071 | |
43c09851 | 1072 | def keyxform(me, key): |
494b719c MW |
1073 | """Transform the KEY (actually a password tag) into a password label.""" |
1074 | return me.k.h().hash(me.magic).hash(key).done() | |
d1c45f5c | 1075 | |
43c09851 | 1076 | def changepp(me): |
d1c45f5c MW |
1077 | """ |
1078 | Change the database password. | |
1079 | ||
1080 | Requests the new password from the Pixie, which will probably cause | |
1081 | interaction. | |
1082 | """ | |
494b719c | 1083 | tag = me.db.get_meta('tag') |
43c09851 | 1084 | _C.ppcancel(tag) |
1085 | ppk = PPK(_C.ppread(tag, _C.PMODE_VERIFY), | |
d1c45f5c | 1086 | me.k.c.__class__, me.k.h, me.k.m.__class__) |
494b719c MW |
1087 | kct = ppk.encrypt(_C.WriteBuffer().putblk16(me.ck).putblk16(me.mk)) |
1088 | me.db.put_meta('key', kct) | |
1089 | me.db.put_meta('salt', ppk.salt) | |
d1c45f5c | 1090 | |
43c09851 | 1091 | def pack(me, key, value): |
494b719c | 1092 | """Pack the KEY and VALUE into a ciphertext, and return it.""" |
9a7b948f MW |
1093 | b = _C.WriteBuffer() |
1094 | b.putblk16(key).putblk16(value) | |
1095 | b.zero(((b.size + 255) & ~255) - b.size) | |
1096 | return me.k.encrypt(b) | |
d1c45f5c MW |
1097 | |
1098 | def unpack(me, ct): | |
1099 | """ | |
1100 | Unpack a ciphertext CT and return a (KEY, VALUE) pair. | |
1101 | ||
1102 | Might raise DecryptError, of course. | |
1103 | """ | |
9a7b948f MW |
1104 | b = _C.ReadBuffer(me.k.decrypt(ct)) |
1105 | key = b.getblk16() | |
1106 | value = b.getblk16() | |
43c09851 | 1107 | return key, value |
d1c45f5c MW |
1108 | |
1109 | ## Mapping protocol. | |
1110 | ||
43c09851 | 1111 | def __getitem__(me, key): |
494b719c MW |
1112 | """Return the password for the given KEY.""" |
1113 | try: return me.unpack(me.db.get_passwd(me.keyxform(key)))[1] | |
e3b6c0d3 | 1114 | except KeyError: raise KeyError(key) |
d1c45f5c | 1115 | |
43c09851 | 1116 | def __setitem__(me, key, value): |
494b719c MW |
1117 | """Associate the password VALUE with the KEY.""" |
1118 | me.db.put_passwd(me.keyxform(key), me.pack(key, value)) | |
d1c45f5c | 1119 | |
43c09851 | 1120 | def __delitem__(me, key): |
494b719c MW |
1121 | """Forget all about the KEY.""" |
1122 | try: me.db.del_passwd(me.keyxform(key)) | |
e3b6c0d3 | 1123 | except KeyError: raise KeyError(key) |
d1c45f5c | 1124 | |
43c09851 | 1125 | def __iter__(me): |
494b719c MW |
1126 | """Iterate over the known password tags.""" |
1127 | for _, pld in me.db.iter_passwds(): | |
1128 | yield me.unpack(pld)[0] | |
43c09851 | 1129 | |
5bf6e9f5 MW |
1130 | ## Context protocol. |
1131 | ||
1132 | def __enter__(me): | |
1133 | return me | |
1134 | def __exit__(me, excty, excval, exctb): | |
053c2659 | 1135 | me.db.close(excval is not None) |
5bf6e9f5 | 1136 | |
d1c45f5c | 1137 | ###----- That's all, folks -------------------------------------------------- |