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00b3cd10 PG |
1 | #!/usr/bin/env python3 |
2 | ||
3 | """ | |
83f2d71e | 4 | Intra2net 2017 |
00b3cd10 PG |
5 | |
6 | =============================================================================== | |
704ceaa5 | 7 | crypto -- Encryption Layer for the Deltatar Backup |
00b3cd10 PG |
8 | =============================================================================== |
9 | ||
10 | Crypto stack: | |
11 | ||
12 | - AES-GCM for the symmetric encryption; | |
13 | - Scrypt as KDF. | |
14 | ||
15 | References: | |
16 | ||
17 | - NIST Recommendation for Block Cipher Modes of Operation: Galois/Counter | |
18 | Mode (GCM) and GMAC | |
19 | http://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38d.pdf | |
20 | ||
21 | - AES-GCM v1: | |
22 | https://cryptome.org/2014/01/aes-gcm-v1.pdf | |
23 | ||
24 | - Authentication weaknesses in GCM | |
25 | http://csrc.nist.gov/groups/ST/toolkit/BCM/documents/comments/CWC-GCM/Ferguson2.pdf | |
26 | ||
83f2d71e PG |
27 | Trouble with python-cryptography packages: authentication tags can only be |
28 | passed in advance: https://github.com/pyca/cryptography/pull/3421 | |
29 | ||
6d08915c PG |
30 | Errors |
31 | ------------------------------------------------------------------------------- | |
32 | ||
33 | Errors fall into roughly three categories: | |
34 | ||
704ceaa5 | 35 | - Cryptographical errors or invalid data. |
6d08915c PG |
36 | |
37 | - ``InvalidGCMTag`` (decryption failed on account of an invalid GCM | |
38 | tag), | |
39 | - ``InvalidIVFixedPart`` (IV fixed part of object not found in list), | |
f6cd676f | 40 | - ``DuplicateIV`` (the IV of an encrypted object already occurred), |
704ceaa5 PG |
41 | - ``DecryptionError`` (used in CLI decryption for presenting error |
42 | conditions to the user). | |
6d08915c PG |
43 | |
44 | - Incorrect usage of the library. | |
45 | ||
46 | - ``InvalidParameter`` (non-conforming user supplied parameter), | |
47 | - ``InvalidHeader`` (data passed for reading not parsable into header), | |
48 | - ``FormatError`` (cannot handle header or parameter version), | |
49 | - ``RuntimeError``. | |
50 | ||
51 | - Bad internal state. If one of these is encountered it means that a state | |
52 | was reached that shouldn’t occur during normal processing. | |
53 | ||
54 | - ``InternalError``, | |
55 | - ``Unreachable``. | |
56 | ||
57 | Also, ``EndOfFile`` is used as a sentinel to communicate that a stream supplied | |
58 | for reading is exhausted. | |
59 | ||
f6cd676f PG |
60 | Initialization Vectors |
61 | ------------------------------------------------------------------------------- | |
62 | ||
63 | Initialization vectors are checked reuse during the lifetime of a decryptor. | |
704ceaa5 PG |
64 | The fixed counters for metadata files cannot be reused and attempts to do so |
65 | will cause a DuplicateIV error. This means the length of objects encrypted with | |
66 | a metadata counter is capped at 63 GB. | |
67 | ||
68 | For ordinary, non-metadata payload, there is an optional mode with strict IV | |
69 | checking that causes a crypto context to fail if an IV encountered or created | |
70 | was already used for decrypting or encrypting, respectively, an earlier object. | |
71 | Note that this mode can trigger false positives when decrypting non-linearly, | |
72 | e. g. when traversing the same object multiple times. Since the crypto context | |
73 | has no notion of a position in a PDT encrypted archive, this condition must be | |
74 | sorted out downstream. | |
75 | ||
76 | Command Line Utility | |
77 | ------------------------------------------------------------------------------- | |
78 | ||
79 | ``crypto.py`` may be invoked as a script for decrypting, validating, and | |
80 | splitting PDT encrypted files. Consult the usage message for details. | |
81 | ||
82 | Usage examples: | |
83 | ||
84 | Decrypt from stdin using the password ‘foo’: :: | |
85 | ||
86 | $ crypto.py process foo -i - -o - <some-file.tar.gz.pdtcrypt >some-file.tar.gz | |
87 | ||
88 | Output verbose information about the encrypted objects in the archive: :: | |
89 | ||
90 | $ crypto.py process foo -v -i some-file.tar.gz.pdtcrypt -o /dev/null | |
91 | PDT: decrypt from some-file.tar.gz.pdtcrypt | |
92 | PDT: decrypt to /dev/null | |
93 | PDT: source: file some-file.tar.gz.pdtcrypt | |
94 | PDT: sink: file /dev/null | |
95 | PDT: 0 hdr | |
96 | PDT: · version = 1 : 0100 | |
97 | PDT: · paramversion = 1 : 0100 | |
98 | PDT: · nacl : d270 b031 00d1 87e2 c946 610d 7b7f 7e5f | |
99 | PDT: · iv : 02ee 3dd7 a963 1eb1 0100 0000 | |
100 | PDT: · ctsize = 591 : 4f02 0000 0000 0000 | |
101 | PDT: · tag : 5b2d 6d8b 8f82 4842 12fd 0b10 b6e3 369b | |
102 | PDT: 64 decrypt obj no. 1, 591 B | |
103 | PDT: · [64] 0% done, read block (591 B of 591 B remaining) | |
104 | PDT: · decrypt ciphertext 591 B | |
105 | PDT: · decrypt plaintext 591 B | |
106 | PDT: 655 finalize | |
107 | … | |
108 | ||
109 | Also, the mode *scrypt* allows deriving encryption keys. To calculate the | |
110 | encryption key from the password ‘foo’ and the salt of the first object in a | |
111 | PDT encrypted file: :: | |
112 | ||
113 | $ crypto.py scrypt foo -i some-file.pdtcrypt | |
4f6405d6 | 114 | {"paramversion": 1, "salt": "Cqzbk48e3peEjzWto8D0yA==", "key": "JH9EkMwaM4x9F5aim5gK/Q=="} |
704ceaa5 PG |
115 | |
116 | The computed 16 byte key is given in hexadecimal notation in the value to | |
117 | ``hash`` and can be fed into Python’s ``binascii.unhexlify()`` to obtain the | |
118 | corresponding binary representation. | |
119 | ||
120 | Note that in Scrypt hashing mode, no data integrity checks are being performed. | |
121 | If the wrong password is given, a wrong key will be derived. Whether the password | |
122 | was indeed correct can only be determined by decrypting. Note that since PDT | |
123 | archives essentially consist of a stream of independent objects, the salt and | |
124 | other parameters may change. Thus a key derived using above method from the | |
125 | first object doesn’t necessarily apply to any of the subsequent objects. | |
f6cd676f | 126 | |
00b3cd10 PG |
127 | """ |
128 | ||
7b3940e5 | 129 | import base64 |
00b3cd10 | 130 | import binascii |
50710d86 | 131 | import bisect |
00b3cd10 PG |
132 | import ctypes |
133 | import io | |
c46c8670 | 134 | from functools import reduce, partial |
f41973a6 | 135 | import mmap |
00b3cd10 PG |
136 | import os |
137 | import struct | |
138 | import sys | |
139 | import time | |
da82bc58 | 140 | import types |
00b3cd10 PG |
141 | try: |
142 | import enum34 | |
143 | except ImportError as exn: | |
144 | pass | |
145 | ||
146 | if __name__ == "__main__": ## Work around the import mechanism’s lest Python’s | |
147 | pwd = os.getcwd() ## preference for local imports causes a cyclical | |
148 | ## import (crypto → pylibscrypt → […] → ./tarfile → crypto). | |
149 | sys.path = [ p for p in sys.path if p.find ("deltatar") < 0 ] | |
150 | ||
151 | import pylibscrypt | |
152 | from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes | |
153 | from cryptography.hazmat.backends import default_backend | |
15d3eefd | 154 | import cryptography |
00b3cd10 PG |
155 | |
156 | ||
a64085a8 | 157 | __all__ = [ "hdr_make", "hdr_read", "hdr_fmt", "hdr_fmt_pretty" |
b360b772 | 158 | , "scrypt_hashfile" |
3031b7ae PG |
159 | , "PDTCRYPT_HDR_SIZE", "AES_GCM_IV_CNT_DATA" |
160 | , "AES_GCM_IV_CNT_INFOFILE", "AES_GCM_IV_CNT_INDEX" | |
2d6fd8c8 | 161 | ] |
00b3cd10 | 162 | |
a393d9cb PG |
163 | |
164 | ############################################################################### | |
15d3eefd PG |
165 | ## exceptions |
166 | ############################################################################### | |
167 | ||
168 | class EndOfFile (Exception): | |
169 | """Reached EOF.""" | |
ae3d0f2a PG |
170 | remainder = 0 |
171 | msg = 0 | |
8a8ac469 | 172 | def __init__ (self, n=None, msg=None): |
5d394c0d PG |
173 | if n is not None: |
174 | self.remainder = n | |
175 | self.msg = msg | |
15d3eefd | 176 | |
b0078f26 | 177 | |
b12110dd PG |
178 | class InvalidParameter (Exception): |
179 | """Inputs not valid for PDT encryption.""" | |
180 | pass | |
181 | ||
b0078f26 | 182 | |
15d3eefd PG |
183 | class InvalidHeader (Exception): |
184 | """Header not valid.""" | |
185 | pass | |
186 | ||
b0078f26 PG |
187 | |
188 | class InvalidGCMTag (Exception): | |
189 | """ | |
190 | The GCM tag calculated during decryption differs from that in the object | |
191 | header. | |
192 | """ | |
193 | pass | |
194 | ||
195 | ||
26b42ad4 | 196 | class InvalidIVFixedPart (Exception): |
89ec6e2f PG |
197 | """ |
198 | IV fixed part not in supplied list: either the backup is corrupt or the | |
199 | current object does not belong to it. | |
200 | """ | |
26b42ad4 PG |
201 | pass |
202 | ||
b0078f26 | 203 | |
be124bca | 204 | class IVFixedPartError (Exception): |
89ec6e2f PG |
205 | """ |
206 | Error creating a unique IV fixed part: repeated calls to system RNG yielded | |
207 | the same sequence of bytes as the last IV used. | |
208 | """ | |
be124bca PG |
209 | pass |
210 | ||
211 | ||
fac2cfe1 | 212 | class InvalidFileCounter (Exception): |
89ec6e2f PG |
213 | """ |
214 | When encrypting, an attempted reuse of a dedicated counter (info file, | |
215 | index file) was caught. | |
216 | """ | |
fac2cfe1 PG |
217 | pass |
218 | ||
219 | ||
ee6aa239 | 220 | class DuplicateIV (Exception): |
89ec6e2f PG |
221 | """ |
222 | During encryption, the current IV fixed part is identical to an already | |
223 | existing IV (same prefix and file counter). This indicates tampering or | |
224 | programmer error and cannot be recovered from. | |
225 | """ | |
ee6aa239 PG |
226 | pass |
227 | ||
228 | ||
229 | class NonConsecutiveIV (Exception): | |
89ec6e2f PG |
230 | """ |
231 | IVs not numbered consecutively. This is a hard error with strict IV | |
232 | checking. Precludes random access to the encrypted objects. | |
233 | """ | |
ee6aa239 PG |
234 | pass |
235 | ||
236 | ||
b12110dd PG |
237 | class FormatError (Exception): |
238 | """Unusable parameters in header.""" | |
239 | pass | |
240 | ||
b0078f26 | 241 | |
15d3eefd | 242 | class DecryptionError (Exception): |
89ec6e2f | 243 | """Error during decryption with ``crypto.py`` on the command line.""" |
15d3eefd PG |
244 | pass |
245 | ||
b0078f26 | 246 | |
70ad9458 | 247 | class Unreachable (Exception): |
89ec6e2f PG |
248 | """ |
249 | Makeshift __builtin_unreachable(); always a programmer error if | |
250 | thrown. | |
251 | """ | |
70ad9458 PG |
252 | pass |
253 | ||
b0078f26 | 254 | |
b12110dd PG |
255 | class InternalError (Exception): |
256 | """Errors not ascribable to bad user inputs or cryptography.""" | |
257 | pass | |
258 | ||
15d3eefd PG |
259 | |
260 | ############################################################################### | |
a393d9cb PG |
261 | ## crypto layer version |
262 | ############################################################################### | |
263 | ||
264 | ENCRYPTION_PARAMETERS = \ | |
c46c8670 | 265 | { 0: \ |
dd23cbc9 PG |
266 | { "kdf": ("dummy", 16) |
267 | , "enc": "passthrough" } | |
c46c8670 | 268 | , 1: \ |
dd23cbc9 PG |
269 | { "kdf": ( "scrypt" |
270 | , { "dkLen" : 16 | |
271 | , "N" : 1 << 16 | |
272 | , "r" : 8 | |
273 | , "p" : 1 | |
274 | , "NaCl_LEN" : 16 }) | |
275 | , "enc": "aes-gcm" } } | |
a393d9cb | 276 | |
00b3cd10 PG |
277 | ############################################################################### |
278 | ## constants | |
279 | ############################################################################### | |
280 | ||
dd47d6a2 | 281 | PDTCRYPT_HDR_MAGIC = b"PDTCRYPT" |
00b3cd10 | 282 | |
dd47d6a2 PG |
283 | PDTCRYPT_HDR_SIZE_MAGIC = 8 # 8 |
284 | PDTCRYPT_HDR_SIZE_VERSION = 2 # 10 | |
285 | PDTCRYPT_HDR_SIZE_PARAMVERSION = 2 # 12 | |
286 | PDTCRYPT_HDR_SIZE_NACL = 16 # 28 | |
287 | PDTCRYPT_HDR_SIZE_IV = 12 # 40 | |
288 | PDTCRYPT_HDR_SIZE_CTSIZE = 8 # 48 | |
289 | PDTCRYPT_HDR_SIZE_TAG = 16 # 64 GCM auth tag | |
00b3cd10 | 290 | |
dd47d6a2 PG |
291 | PDTCRYPT_HDR_SIZE = PDTCRYPT_HDR_SIZE_MAGIC + PDTCRYPT_HDR_SIZE_VERSION \ |
292 | + PDTCRYPT_HDR_SIZE_PARAMVERSION + PDTCRYPT_HDR_SIZE_NACL \ | |
293 | + PDTCRYPT_HDR_SIZE_IV + PDTCRYPT_HDR_SIZE_CTSIZE \ | |
294 | + PDTCRYPT_HDR_SIZE_TAG # = 64 | |
00b3cd10 PG |
295 | |
296 | # precalculate offsets since Python can’t do constant folding over names | |
dd47d6a2 PG |
297 | HDR_OFF_VERSION = PDTCRYPT_HDR_SIZE_MAGIC |
298 | HDR_OFF_PARAMVERSION = HDR_OFF_VERSION + PDTCRYPT_HDR_SIZE_VERSION | |
299 | HDR_OFF_NACL = HDR_OFF_PARAMVERSION + PDTCRYPT_HDR_SIZE_PARAMVERSION | |
300 | HDR_OFF_IV = HDR_OFF_NACL + PDTCRYPT_HDR_SIZE_NACL | |
301 | HDR_OFF_CTSIZE = HDR_OFF_IV + PDTCRYPT_HDR_SIZE_IV | |
302 | HDR_OFF_TAG = HDR_OFF_CTSIZE + PDTCRYPT_HDR_SIZE_CTSIZE | |
00b3cd10 PG |
303 | |
304 | FMT_UINT16_LE = "<H" | |
305 | FMT_UINT64_LE = "<Q" | |
50710d86 | 306 | FMT_I2N_IV = "<8sL" # 8 random bytes ‖ 32 bit counter |
83f2d71e PG |
307 | FMT_I2N_HDR = ("<" # host byte order |
308 | "8s" # magic | |
309 | "H" # version | |
310 | "H" # paramversion | |
311 | "16s" # sodium chloride | |
312 | "12s" # iv | |
3b53fb98 PG |
313 | "Q" # size |
314 | "16s") # GCM tag | |
00b3cd10 PG |
315 | |
316 | # aes+gcm | |
cb7a3911 PG |
317 | AES_GCM_MAX_SIZE = (1 << 36) - (1 << 5) # 2^39 - 2^8 b ≅ 64 GB |
318 | PDTCRYPT_MAX_OBJ_SIZE_DEFAULT = 63 * (1 << 30) # 63 GB | |
319 | PDTCRYPT_MAX_OBJ_SIZE = PDTCRYPT_MAX_OBJ_SIZE_DEFAULT | |
00b3cd10 | 320 | |
3031b7ae PG |
321 | # index and info files are written on-the fly while encrypting so their |
322 | # counters must be available inadvance | |
cb7a3911 PG |
323 | AES_GCM_IV_CNT_INFOFILE = 1 # constant |
324 | AES_GCM_IV_CNT_INDEX = AES_GCM_IV_CNT_INFOFILE + 1 | |
325 | AES_GCM_IV_CNT_DATA = AES_GCM_IV_CNT_INDEX + 1 # also for multivolume | |
326 | AES_GCM_IV_CNT_MAX_DEFAULT = 0xffFFffFF | |
327 | AES_GCM_IV_CNT_MAX = AES_GCM_IV_CNT_MAX_DEFAULT | |
2d6fd8c8 | 328 | |
be124bca PG |
329 | # IV structure and generation |
330 | PDTCRYPT_IV_GEN_MAX_RETRIES = 10 # × | |
331 | PDTCRYPT_IV_FIXEDPART_SIZE = 8 # B | |
332 | PDTCRYPT_IV_COUNTER_SIZE = 4 # B | |
39accaaa | 333 | |
00b3cd10 | 334 | ############################################################################### |
39accaaa | 335 | ## header, trailer |
00b3cd10 PG |
336 | ############################################################################### |
337 | # | |
338 | # Interface: | |
339 | # | |
340 | # struct hdrinfo | |
341 | # { version : u16 | |
342 | # , paramversion : u16 | |
343 | # , nacl : [u8; 16] | |
344 | # , iv : [u8; 12] | |
704ceaa5 PG |
345 | # , ctsize : usize |
346 | # , tag : [u8; 16] } | |
83f2d71e | 347 | # |
00b3cd10 | 348 | # fn hdr_read (f : handle) -> hdrinfo; |
c2d1c3ec | 349 | # fn hdr_make (f : handle, h : hdrinfo) -> IOResult<usize>; |
00b3cd10 PG |
350 | # fn hdr_fmt (h : hdrinfo) -> String; |
351 | # | |
352 | ||
83f2d71e | 353 | def hdr_read (data): |
704ceaa5 PG |
354 | """ |
355 | Read bytes as header structure. | |
356 | ||
357 | If the input could not be interpreted as a header, fail with | |
358 | ``InvalidHeader``. | |
359 | """ | |
83f2d71e | 360 | |
00b3cd10 | 361 | try: |
3b53fb98 | 362 | mag, version, paramversion, nacl, iv, ctsize, tag = \ |
83f2d71e PG |
363 | struct.unpack (FMT_I2N_HDR, data) |
364 | except Exception as exn: | |
15d3eefd PG |
365 | raise InvalidHeader ("error unpacking header from [%r]: %s" |
366 | % (binascii.hexlify (data), str (exn))) | |
00b3cd10 | 367 | |
dd47d6a2 | 368 | if mag != PDTCRYPT_HDR_MAGIC: |
15d3eefd | 369 | raise InvalidHeader ("bad magic in header: expected [%s], got [%s]" |
dd47d6a2 | 370 | % (PDTCRYPT_HDR_MAGIC, mag)) |
00b3cd10 | 371 | |
15d3eefd | 372 | return \ |
00b3cd10 PG |
373 | { "version" : version |
374 | , "paramversion" : paramversion | |
375 | , "nacl" : nacl | |
376 | , "iv" : iv | |
377 | , "ctsize" : ctsize | |
3b53fb98 | 378 | , "tag" : tag |
00b3cd10 PG |
379 | } |
380 | ||
381 | ||
39accaaa | 382 | def hdr_read_stream (instr): |
704ceaa5 PG |
383 | """ |
384 | Read header from stream at the current position. | |
385 | ||
386 | Fail with ``InvalidHeader`` if insufficient bytes were read from the | |
387 | stream, or if the content could not be interpreted as a header. | |
388 | """ | |
dd47d6a2 | 389 | data = instr.read(PDTCRYPT_HDR_SIZE) |
ae3d0f2a | 390 | ldata = len (data) |
8a8ac469 PG |
391 | if ldata == 0: |
392 | raise EndOfFile | |
393 | elif ldata != PDTCRYPT_HDR_SIZE: | |
394 | raise InvalidHeader ("hdr_read_stream: expected %d B, received %d B" | |
395 | % (PDTCRYPT_HDR_SIZE, ldata)) | |
47e27926 | 396 | return hdr_read (data) |
39accaaa PG |
397 | |
398 | ||
3b53fb98 | 399 | def hdr_from_params (version, paramversion, nacl, iv, ctsize, tag): |
704ceaa5 PG |
400 | """ |
401 | Assemble the necessary values into a PDTCRYPT header. | |
402 | ||
403 | :type version: int to fit uint16_t | |
404 | :type paramversion: int to fit uint16_t | |
405 | :type nacl: bytes to fit uint8_t[16] | |
406 | :type iv: bytes to fit uint8_t[12] | |
407 | :type size: int to fit uint64_t | |
408 | :type tag: bytes to fit uint8_t[16] | |
409 | """ | |
dd47d6a2 | 410 | buf = bytearray (PDTCRYPT_HDR_SIZE) |
83f2d71e | 411 | bufv = memoryview (buf) |
00b3cd10 | 412 | |
00b3cd10 | 413 | try: |
83f2d71e | 414 | struct.pack_into (FMT_I2N_HDR, bufv, 0, |
dd47d6a2 | 415 | PDTCRYPT_HDR_MAGIC, |
3b53fb98 | 416 | version, paramversion, nacl, iv, ctsize, tag) |
83f2d71e | 417 | except Exception as exn: |
a83fa4ed | 418 | return False, "error assembling header: %s" % str (exn) |
00b3cd10 | 419 | |
83f2d71e | 420 | return True, bytes (buf) |
00b3cd10 | 421 | |
00b3cd10 | 422 | |
8a990744 PG |
423 | def hdr_make_dummy (s): |
424 | """ | |
425 | Create a header sized block of bytes initialized to a value derived from a | |
426 | string. Used to verify we’ve jumped back correctly to the actual position | |
427 | of the object header. | |
428 | """ | |
429 | c = reduce (lambda a, c: a + ord(c), s, 0) % 0xFF | |
dd47d6a2 | 430 | return bytes (bytearray (struct.pack ("B", c)) * PDTCRYPT_HDR_SIZE) |
8a990744 PG |
431 | |
432 | ||
a393d9cb | 433 | def hdr_make (hdr): |
704ceaa5 PG |
434 | """ |
435 | Assemble a header from the given header structure. | |
436 | """ | |
a393d9cb PG |
437 | return hdr_from_params (version=hdr.get("version"), |
438 | paramversion=hdr.get("paramversion"), | |
439 | nacl=hdr.get("nacl"), iv=hdr.get("iv"), | |
3b53fb98 | 440 | ctsize=hdr.get("ctsize"), tag=hdr.get("tag")) |
a393d9cb PG |
441 | |
442 | ||
83f2d71e | 443 | HDR_FMT = "I2n_header { version: %d, paramversion: %d, nacl: %s[%d]," \ |
89131745 | 444 | " iv: %s[%d], ctsize: %d, tag: %s[%d] }" |
00b3cd10 | 445 | |
83f2d71e | 446 | def hdr_fmt (h): |
704ceaa5 | 447 | """Format a header structure into readable output.""" |
83f2d71e PG |
448 | return HDR_FMT % (h["version"], h["paramversion"], |
449 | binascii.hexlify (h["nacl"]), len(h["nacl"]), | |
450 | binascii.hexlify (h["iv"]), len(h["iv"]), | |
db1f3ac7 PG |
451 | h["ctsize"], |
452 | binascii.hexlify (h["tag"]), len(h["tag"])) | |
00b3cd10 | 453 | |
00b3cd10 | 454 | |
83f2d71e | 455 | def hex_spaced_of_bytes (b): |
704ceaa5 | 456 | """Format bytes object, hexdump style.""" |
83f2d71e PG |
457 | return " ".join ([ "%.2x%.2x" % (c1, c2) |
458 | for c1, c2 in zip (b[0::2], b[1::2]) ]) \ | |
459 | + (len (b) | 1 == len (b) and " %.2x" % b[-1] or "") # odd lengths | |
00b3cd10 | 460 | |
591a722f | 461 | |
3031b7ae PG |
462 | def hdr_iv_counter (h): |
463 | """Extract the variable part of the IV of the given header.""" | |
464 | _fixed, cnt = struct.unpack (FMT_I2N_IV, h ["iv"]) | |
465 | return cnt | |
466 | ||
467 | ||
468 | def hdr_iv_fixed (h): | |
469 | """Extract the fixed part of the IV of the given header.""" | |
470 | fixed, _cnt = struct.unpack (FMT_I2N_IV, h ["iv"]) | |
471 | return fixed | |
472 | ||
473 | ||
83f2d71e | 474 | hdr_dump = hex_spaced_of_bytes |
00b3cd10 | 475 | |
00b3cd10 | 476 | |
15d3eefd PG |
477 | HDR_FMT_PRETTY = \ |
478 | """version = %-4d : %s | |
479 | paramversion = %-4d : %s | |
480 | nacl : %s | |
481 | iv : %s | |
482 | ctsize = %-20d : %s | |
483 | tag : %s | |
83f2d71e | 484 | """ |
00b3cd10 | 485 | |
83f2d71e | 486 | def hdr_fmt_pretty (h): |
704ceaa5 PG |
487 | """ |
488 | Format header structure into multi-line representation of its contents and | |
489 | their raw representation. (Omit the implicit “PDTCRYPT” magic bytes that | |
490 | precede every header.) | |
491 | """ | |
83f2d71e PG |
492 | return HDR_FMT_PRETTY \ |
493 | % (h["version"], | |
494 | hex_spaced_of_bytes (struct.pack (FMT_UINT16_LE, h["version"])), | |
495 | h["paramversion"], | |
496 | hex_spaced_of_bytes (struct.pack (FMT_UINT16_LE, h["paramversion"])), | |
497 | hex_spaced_of_bytes (h["nacl"]), | |
498 | hex_spaced_of_bytes (h["iv"]), | |
499 | h["ctsize"], | |
15d3eefd PG |
500 | hex_spaced_of_bytes (struct.pack (FMT_UINT64_LE, h["ctsize"])), |
501 | hex_spaced_of_bytes (h["tag"])) | |
00b3cd10 | 502 | |
f6cd676f PG |
503 | IV_FMT = "((f %s) (c %d))" |
504 | ||
505 | def iv_fmt (iv): | |
704ceaa5 | 506 | """Format the two components of an IV in a readable fashion.""" |
f6cd676f PG |
507 | fixed, cnt = struct.unpack (FMT_I2N_IV, iv) |
508 | return IV_FMT % (binascii.hexlify (fixed), cnt) | |
509 | ||
00b3cd10 | 510 | |
00b3cd10 | 511 | ############################################################################### |
f41973a6 PG |
512 | ## restoration |
513 | ############################################################################### | |
514 | ||
515 | class Location (object): | |
516 | n = 0 | |
517 | offset = 0 | |
518 | ||
519 | def restore_loc_fmt (loc): | |
520 | return "%d off:%d" \ | |
521 | % (loc.n, loc.offset) | |
522 | ||
523 | def locate_hdr_candidates (fd): | |
524 | """ | |
525 | Walk over instances of the magic string in the payload, collecting their | |
526 | positions. If the offset of the first found instance is not zero, the file | |
527 | begins with leading garbage. | |
528 | ||
529 | :return: The list of offsets in the file. | |
530 | """ | |
531 | cands = [] | |
532 | ||
533 | mm = mmap.mmap(fd, 0, mmap.MAP_SHARED, mmap.PROT_READ) | |
534 | pos = 0 | |
535 | while True: | |
536 | pos = mm.find (PDTCRYPT_HDR_MAGIC, pos) | |
537 | if pos == -1: | |
538 | break | |
539 | cands.append (pos) | |
540 | pos += 1 | |
541 | ||
542 | return cands | |
543 | ||
544 | ||
545 | ############################################################################### | |
6178061e PG |
546 | ## passthrough / null encryption |
547 | ############################################################################### | |
548 | ||
549 | class PassthroughCipher (object): | |
550 | ||
551 | tag = struct.pack ("<QQ", 0, 0) | |
552 | ||
553 | def __init__ (self) : pass | |
554 | ||
555 | def update (self, b) : return b | |
556 | ||
50710d86 | 557 | def finalize (self) : return b"" |
6178061e PG |
558 | |
559 | def finalize_with_tag (self, _) : return b"" | |
560 | ||
561 | ############################################################################### | |
a393d9cb | 562 | ## convenience wrapper |
00b3cd10 PG |
563 | ############################################################################### |
564 | ||
c46c8670 PG |
565 | |
566 | def kdf_dummy (klen, password, _nacl): | |
704ceaa5 PG |
567 | """ |
568 | Fake KDF for testing purposes that is called when parameter version zero is | |
569 | encountered. | |
570 | """ | |
c46c8670 PG |
571 | q, r = divmod (klen, len (password)) |
572 | if isinstance (password, bytes) is False: | |
573 | password = password.encode () | |
574 | return password * q + password [:r], b"" | |
575 | ||
576 | ||
577 | SCRYPT_KEY_MEMO = { } # static because needed for both the info file and the archive | |
578 | ||
579 | ||
580 | def kdf_scrypt (params, password, nacl): | |
704ceaa5 PG |
581 | """ |
582 | Wrapper for the Scrypt KDF, corresponds to parameter version one. The | |
583 | computation result is memoized based on the inputs to facilitate spawning | |
584 | multiple encryption contexts. | |
585 | """ | |
c46c8670 PG |
586 | N = params["N"] |
587 | r = params["r"] | |
588 | p = params["p"] | |
589 | dkLen = params["dkLen"] | |
590 | ||
591 | if nacl is None: | |
592 | nacl = os.urandom (params["NaCl_LEN"]) | |
593 | ||
594 | key_parms = (password, nacl, N, r, p, dkLen) | |
595 | global SCRYPT_KEY_MEMO | |
596 | if key_parms not in SCRYPT_KEY_MEMO: | |
597 | SCRYPT_KEY_MEMO [key_parms] = \ | |
598 | pylibscrypt.scrypt (password, nacl, N, r, p, dkLen) | |
599 | return SCRYPT_KEY_MEMO [key_parms], nacl | |
a64085a8 PG |
600 | |
601 | ||
da82bc58 | 602 | def kdf_by_version (paramversion=None, defs=None): |
704ceaa5 PG |
603 | """ |
604 | Pick the KDF handler corresponding to the parameter version or the | |
605 | definition set. | |
606 | ||
607 | :rtype: function (password : str, nacl : str) -> str | |
608 | """ | |
da82bc58 PG |
609 | if paramversion is not None: |
610 | defs = ENCRYPTION_PARAMETERS.get(paramversion, None) | |
a64085a8 | 611 | if defs is None: |
1ed44e7b PG |
612 | raise InvalidParameter ("no encryption parameters for version %r" |
613 | % paramversion) | |
a64085a8 | 614 | (kdf, params) = defs["kdf"] |
c46c8670 PG |
615 | fn = None |
616 | if kdf == "scrypt" : fn = kdf_scrypt | |
617 | if kdf == "dummy" : fn = kdf_dummy | |
618 | if fn is None: | |
a64085a8 | 619 | raise ValueError ("key derivation method %r unknown" % kdf) |
c46c8670 | 620 | return partial (fn, params) |
a64085a8 PG |
621 | |
622 | ||
b360b772 PG |
623 | ############################################################################### |
624 | ## SCRYPT hashing | |
625 | ############################################################################### | |
626 | ||
627 | def scrypt_hashsource (pw, ins): | |
628 | """ | |
629 | Calculate the SCRYPT hash from the password and the information contained | |
630 | in the first header found in ``ins``. | |
631 | ||
632 | This does not validate whether the first object is encrypted correctly. | |
633 | """ | |
c1ecc2e2 PG |
634 | if isinstance (pw, str) is True: |
635 | pw = str.encode (pw) | |
636 | elif isinstance (pw, bytes) is False: | |
637 | raise InvalidParameter ("password must be a string, not %s" | |
638 | % type (password)) | |
639 | if isinstance (ins, io.BufferedReader) is False and \ | |
640 | isinstance (ins, io.FileIO) is False: | |
641 | raise InvalidParameter ("file to hash must be opened in “binary” mode") | |
b360b772 PG |
642 | hdr = None |
643 | try: | |
644 | hdr = hdr_read_stream (ins) | |
645 | except EndOfFile as exn: | |
646 | noise ("PDT: malformed input: end of file reading first object header") | |
647 | noise ("PDT:") | |
648 | return 1 | |
649 | ||
650 | nacl = hdr ["nacl"] | |
651 | pver = hdr ["paramversion"] | |
652 | if PDTCRYPT_VERBOSE is True: | |
653 | noise ("PDT: salt of first object : %s" % binascii.hexlify (nacl)) | |
654 | noise ("PDT: parameter version of archive : %d" % pver) | |
655 | ||
656 | try: | |
657 | defs = ENCRYPTION_PARAMETERS.get(pver, None) | |
658 | kdfname, params = defs ["kdf"] | |
659 | if kdfname != "scrypt": | |
660 | noise ("PDT: input is not an SCRYPT archive") | |
661 | noise ("") | |
662 | return 1 | |
663 | kdf = kdf_by_version (None, defs) | |
664 | except ValueError as exn: | |
665 | noise ("PDT: object has unknown parameter version %d" % pver) | |
666 | ||
667 | hsh, _void = kdf (pw, nacl) | |
668 | ||
c1ecc2e2 | 669 | return hsh, nacl, hdr ["version"], pver |
b360b772 PG |
670 | |
671 | ||
672 | def scrypt_hashfile (pw, fname): | |
704ceaa5 PG |
673 | """ |
674 | Calculate the SCRYPT hash from the password and the information contained | |
675 | in the first header found in the given file. The header is read only at | |
676 | offset zero. | |
677 | """ | |
b360b772 | 678 | with deptdcrypt_mk_stream (PDTCRYPT_SOURCE, fname or "-") as ins: |
c1ecc2e2 | 679 | hsh, _void, _void, _void = scrypt_hashsource (pw, ins) |
b360b772 PG |
680 | return hsh |
681 | ||
682 | ||
683 | ############################################################################### | |
684 | ## AES-GCM context | |
685 | ############################################################################### | |
686 | ||
a393d9cb PG |
687 | class Crypto (object): |
688 | """ | |
689 | Encryption context to remain alive throughout an entire tarfile pass. | |
690 | """ | |
6178061e | 691 | enc = None |
a393d9cb PG |
692 | nacl = None |
693 | key = None | |
50710d86 PG |
694 | cnt = None # file counter (uint32_t != 0) |
695 | iv = None # current IV | |
30019abf PG |
696 | fixed = None # accu for 64 bit fixed parts of IV |
697 | used_ivs = None # tracks IVs | |
698 | strict_ivs = False # if True, panic on duplicate object IV | |
48db09ba PG |
699 | password = None |
700 | paramversion = None | |
633b18a9 PG |
701 | stats = { "in" : 0 |
702 | , "out" : 0 | |
703 | , "obj" : 0 } | |
fa47412e | 704 | |
fa47412e PG |
705 | ctsize = -1 |
706 | ptsize = -1 | |
3031b7ae PG |
707 | info_counter_used = False |
708 | index_counter_used = False | |
a393d9cb | 709 | |
a64085a8 | 710 | def __init__ (self, *al, **akv): |
30019abf | 711 | self.used_ivs = set () |
a64085a8 | 712 | self.set_parameters (*al, **akv) |
39accaaa PG |
713 | |
714 | ||
704ceaa5 | 715 | def next_fixed (self): |
be124bca | 716 | # NOP for decryption |
50710d86 PG |
717 | pass |
718 | ||
719 | ||
720 | def set_object_counter (self, cnt=None): | |
704ceaa5 PG |
721 | """ |
722 | Safely set the internal counter of encrypted objects. Numerous | |
723 | constraints apply: | |
724 | ||
725 | The same counter may not be reused in combination with one IV fixed | |
726 | part. This is validated elsewhere in the IV handling. | |
727 | ||
728 | Counter zero is invalid. The first two counters are reserved for | |
729 | metadata. The implementation does not allow for splitting metadata | |
730 | files over multiple encrypted objects. (This would be possible by | |
731 | assigning new fixed parts.) Thus in a Deltatar backup there is at most | |
732 | one object with a counter value of one and two. On creation of a | |
733 | context, the initial counter may be chosen. The globals | |
734 | ``AES_GCM_IV_CNT_INFOFILE`` and ``AES_GCM_IV_CNT_INDEX`` can be used to | |
735 | request one of the reserved values. If one of these values has been | |
736 | used, any further attempt of setting the counter to that value will | |
737 | be rejected with an ``InvalidFileCounter`` exception. | |
738 | ||
739 | Out of bounds values (i. e. below one and more than the maximum of 2³²) | |
740 | cause an ``InvalidParameter`` exception to be thrown. | |
741 | """ | |
50710d86 PG |
742 | if cnt is None: |
743 | self.cnt = AES_GCM_IV_CNT_DATA | |
744 | return | |
745 | if cnt == 0 or cnt > AES_GCM_IV_CNT_MAX + 1: | |
b12110dd PG |
746 | raise InvalidParameter ("invalid counter value %d requested: " |
747 | "acceptable values are from 1 to %d" | |
748 | % (cnt, AES_GCM_IV_CNT_MAX)) | |
50710d86 PG |
749 | if cnt == AES_GCM_IV_CNT_INFOFILE: |
750 | if self.info_counter_used is True: | |
fac2cfe1 PG |
751 | raise InvalidFileCounter ("attempted to reuse info file " |
752 | "counter %d: must be unique" % cnt) | |
50710d86 | 753 | self.info_counter_used = True |
3031b7ae PG |
754 | elif cnt == AES_GCM_IV_CNT_INDEX: |
755 | if self.index_counter_used is True: | |
fac2cfe1 PG |
756 | raise InvalidFileCounter ("attempted to reuse index file " |
757 | " counter %d: must be unique" % cnt) | |
3031b7ae | 758 | self.index_counter_used = True |
50710d86 PG |
759 | if cnt <= AES_GCM_IV_CNT_MAX: |
760 | self.cnt = cnt | |
761 | return | |
762 | # cnt == AES_GCM_IV_CNT_MAX + 1 → wrap | |
763 | self.cnt = AES_GCM_IV_CNT_DATA | |
704ceaa5 | 764 | self.next_fixed () |
50710d86 PG |
765 | |
766 | ||
1f3fd7b0 | 767 | def set_parameters (self, password=None, key=None, paramversion=None, |
be124bca | 768 | nacl=None, counter=None, strict_ivs=False): |
704ceaa5 PG |
769 | """ |
770 | Configure the internal state of a crypto context. Not intended for | |
771 | external use. | |
772 | """ | |
be124bca | 773 | self.next_fixed () |
50710d86 | 774 | self.set_object_counter (counter) |
30019abf PG |
775 | self.strict_ivs = strict_ivs |
776 | ||
a83fa4ed PG |
777 | if paramversion is not None: |
778 | self.paramversion = paramversion | |
779 | ||
1f3fd7b0 PG |
780 | if key is not None: |
781 | self.key, self.nacl = key, nacl | |
782 | return | |
783 | ||
a83fa4ed PG |
784 | if password is not None: |
785 | if isinstance (password, bytes) is False: | |
786 | password = str.encode (password) | |
787 | self.password = password | |
788 | if paramversion is None and nacl is None: | |
789 | # postpone key setup until first header is available | |
790 | return | |
791 | kdf = kdf_by_version (paramversion) | |
792 | if kdf is not None: | |
793 | self.key, self.nacl = kdf (password, nacl) | |
fa47412e | 794 | |
39accaaa | 795 | |
39accaaa | 796 | def process (self, buf): |
704ceaa5 PG |
797 | """ |
798 | Encrypt / decrypt a buffer. Invokes the ``.update()`` method on the | |
799 | wrapped encryptor or decryptor, respectively. | |
800 | ||
801 | The Cryptography exception ``AlreadyFinalized`` is translated to an | |
802 | ``InternalError`` at this point. It may occur in sound code when the GC | |
803 | closes an encrypting stream after an error. Everywhere else it must be | |
804 | treated as a bug. | |
805 | """ | |
cb7a3911 PG |
806 | if self.enc is None: |
807 | raise RuntimeError ("process: context not initialized") | |
808 | self.stats ["in"] += len (buf) | |
fac2cfe1 PG |
809 | try: |
810 | out = self.enc.update (buf) | |
811 | except cryptography.exceptions.AlreadyFinalized as exn: | |
812 | raise InternalError (exn) | |
cb7a3911 PG |
813 | self.stats ["out"] += len (out) |
814 | return out | |
39accaaa PG |
815 | |
816 | ||
30019abf | 817 | def next (self, password, paramversion, nacl, iv): |
704ceaa5 PG |
818 | """ |
819 | Prepare for encrypting another object: Reset the data counters and | |
820 | change the configuration in case one of the variable parameters differs | |
821 | from the last object. Also check the IV for duplicates and error out | |
822 | if strict checking was requested. | |
823 | """ | |
fa47412e PG |
824 | self.ctsize = 0 |
825 | self.ptsize = 0 | |
826 | self.stats ["obj"] += 1 | |
30019abf PG |
827 | |
828 | self.check_duplicate_iv (iv) | |
829 | ||
6178061e PG |
830 | if ( self.paramversion != paramversion |
831 | or self.password != password | |
832 | or self.nacl != nacl): | |
1f3fd7b0 | 833 | self.set_parameters (password=password, paramversion=paramversion, |
30019abf PG |
834 | nacl=nacl, strict_ivs=self.strict_ivs) |
835 | ||
836 | ||
837 | def check_duplicate_iv (self, iv): | |
704ceaa5 PG |
838 | """ |
839 | Add an IV (the 12 byte representation as in the header) to the list. With | |
840 | strict checking enabled, this will throw a ``DuplicateIV``. Depending on | |
841 | the context, this may indicate a serious error (IV reuse). | |
842 | """ | |
30019abf PG |
843 | if self.strict_ivs is True and iv in self.used_ivs: |
844 | raise DuplicateIV ("iv %s was reused" % iv_fmt (iv)) | |
845 | # vi has not been used before; add to collection | |
846 | self.used_ivs.add (iv) | |
fa47412e PG |
847 | |
848 | ||
633b18a9 | 849 | def counters (self): |
704ceaa5 PG |
850 | """ |
851 | Access the data counters. | |
852 | """ | |
633b18a9 PG |
853 | return self.stats ["obj"], self.stats ["in"], self.stats ["out"] |
854 | ||
855 | ||
8de91f4f PG |
856 | def drop (self): |
857 | """ | |
858 | Clear the current context regardless of its finalization state. The | |
859 | next operation must be ``.next()``. | |
860 | """ | |
861 | self.enc = None | |
862 | ||
863 | ||
39accaaa PG |
864 | class Encrypt (Crypto): |
865 | ||
48db09ba PG |
866 | lastinfo = None |
867 | version = None | |
72a42219 | 868 | paramenc = None |
50710d86 | 869 | |
1f3fd7b0 | 870 | def __init__ (self, version, paramversion, password=None, key=None, nacl=None, |
30019abf | 871 | counter=AES_GCM_IV_CNT_DATA, strict_ivs=True): |
704ceaa5 PG |
872 | """ |
873 | The ctor will throw immediately if one of the parameters does not conform | |
874 | to our expectations. | |
875 | ||
876 | counter=AES_GCM_IV_CNT_DATA, strict_ivs=True): | |
877 | :type version: int to fit uint16_t | |
878 | :type paramversion: int to fit uint16_t | |
879 | :param password: mutually exclusive with ``key`` | |
880 | :type password: bytes | |
881 | :param key: mutually exclusive with ``password`` | |
882 | :type key: bytes | |
883 | :type nacl: bytes | |
884 | :type counter: initial object counter the values | |
885 | ``AES_GCM_IV_CNT_INFOFILE`` and | |
886 | ``AES_GCM_IV_CNT_INDEX`` are unique in each backup set | |
887 | and cannot be reused even with different fixed parts. | |
888 | :type strict_ivs: bool | |
889 | """ | |
1f3fd7b0 PG |
890 | if password is None and key is None \ |
891 | or password is not None and key is not None : | |
892 | raise InvalidParameter ("__init__: need either key or password") | |
893 | ||
894 | if key is not None: | |
895 | if isinstance (key, bytes) is False: | |
896 | raise InvalidParameter ("__init__: key must be provided as " | |
897 | "bytes, not %s" % type (key)) | |
898 | if nacl is None: | |
899 | raise InvalidParameter ("__init__: salt must be provided along " | |
900 | "with encryption key") | |
901 | else: # password, no key | |
902 | if isinstance (password, str) is False: | |
903 | raise InvalidParameter ("__init__: password must be a string, not %s" | |
904 | % type (password)) | |
905 | if len (password) == 0: | |
906 | raise InvalidParameter ("__init__: supplied empty password but not " | |
907 | "permitted for PDT encrypted files") | |
36b9932a PG |
908 | # version |
909 | if isinstance (version, int) is False: | |
910 | raise InvalidParameter ("__init__: version number must be an " | |
911 | "integer, not %s" % type (version)) | |
912 | if version < 0: | |
913 | raise InvalidParameter ("__init__: version number must be a " | |
914 | "nonnegative integer, not %d" % version) | |
915 | # paramversion | |
916 | if isinstance (paramversion, int) is False: | |
917 | raise InvalidParameter ("__init__: crypto parameter version number " | |
918 | "must be an integer, not %s" | |
919 | % type (paramversion)) | |
920 | if paramversion < 0: | |
921 | raise InvalidParameter ("__init__: crypto parameter version number " | |
922 | "must be a nonnegative integer, not %d" | |
923 | % paramversion) | |
924 | # salt | |
925 | if nacl is not None: | |
926 | if isinstance (nacl, bytes) is False: | |
927 | raise InvalidParameter ("__init__: salt given, but of type %s " | |
928 | "instead of bytes" % type (nacl)) | |
929 | # salt length would depend on the actual encryption so it can’t be | |
930 | # validated at this point | |
b12110dd | 931 | self.fixed = [ ] |
48db09ba PG |
932 | self.version = version |
933 | self.paramenc = ENCRYPTION_PARAMETERS.get (paramversion) ["enc"] | |
72a42219 | 934 | |
1f3fd7b0 | 935 | super().__init__ (password, key, paramversion, nacl, counter=counter, |
30019abf | 936 | strict_ivs=strict_ivs) |
a393d9cb PG |
937 | |
938 | ||
be124bca PG |
939 | def next_fixed (self, retries=PDTCRYPT_IV_GEN_MAX_RETRIES): |
940 | """ | |
941 | Generate the next IV fixed part by reading eight bytes from | |
942 | ``/dev/urandom``. The buffer so obtained is tested against the fixed | |
943 | parts used so far to prevent accidental reuse of IVs. After a | |
944 | configurable number of attempts to create a unique fixed part, it will | |
945 | refuse to continue with an ``IVFixedPartError``. This is unlikely to | |
946 | ever happen on a normal system but may detect an issue with the random | |
947 | generator. | |
948 | ||
949 | The list of fixed parts that were used by the context at hand can be | |
950 | accessed through the ``.fixed`` list. Its last element is the fixed | |
951 | part currently in use. | |
952 | """ | |
953 | i = 0 | |
954 | while i < retries: | |
955 | fp = os.urandom (PDTCRYPT_IV_FIXEDPART_SIZE) | |
956 | if fp not in self.fixed: | |
957 | self.fixed.append (fp) | |
958 | return | |
959 | i += 1 | |
960 | raise IVFixedPartError ("error obtaining a unique IV fixed part from " | |
961 | "/dev/urandom; giving up after %d tries" % i) | |
962 | ||
963 | ||
a393d9cb | 964 | def iv_make (self): |
704ceaa5 PG |
965 | """ |
966 | Construct a 12-bytes IV from the current fixed part and the object | |
967 | counter. | |
968 | """ | |
b12110dd | 969 | return struct.pack(FMT_I2N_IV, self.fixed [-1], self.cnt) |
a393d9cb PG |
970 | |
971 | ||
cb7a3911 | 972 | def next (self, filename=None, counter=None): |
704ceaa5 PG |
973 | """ |
974 | Prepare for encrypting the next incoming object. Update the counter | |
975 | and put together the IV, possibly changing prefixes. Then create the | |
976 | new encryptor. | |
977 | ||
978 | The argument ``counter`` can be used to specify a file counter for this | |
979 | object. Unless it is one of the reserved values, the counter of | |
980 | subsequent objects will be computed from this one. | |
981 | ||
982 | If this is the first object in a series, ``filename`` is required, | |
983 | otherwise it is reused if not present. The value is used to derive a | |
984 | header sized placeholder to use until after encryption when all the | |
985 | inputs to construct the final header are available. This is then | |
986 | matched in ``.done()`` against the value found at the position of the | |
987 | header. The motivation for this extra check is primarily to assist | |
988 | format debugging: It makes stray headers easy to spot in malformed | |
989 | PDTCRYPT files. | |
990 | """ | |
cb7a3911 PG |
991 | if filename is None: |
992 | if self.lastinfo is None: | |
993 | raise InvalidParameter ("next: filename is mandatory for " | |
994 | "first object") | |
995 | filename, _dummy = self.lastinfo | |
996 | else: | |
997 | if isinstance (filename, str) is False: | |
998 | raise InvalidParameter ("next: filename must be a string, no %s" | |
999 | % type (filename)) | |
3031b7ae PG |
1000 | if counter is not None: |
1001 | if isinstance (counter, int) is False: | |
1002 | raise InvalidParameter ("next: the supplied counter is of " | |
1003 | "invalid type %s; please pass an " | |
1004 | "integer instead" % type (counter)) | |
1005 | self.set_object_counter (counter) | |
fac2cfe1 | 1006 | |
50710d86 | 1007 | self.iv = self.iv_make () |
72a42219 | 1008 | if self.paramenc == "aes-gcm": |
6178061e PG |
1009 | self.enc = Cipher \ |
1010 | ( algorithms.AES (self.key) | |
1011 | , modes.GCM (self.iv) | |
1012 | , backend = default_backend ()) \ | |
1013 | .encryptor () | |
72a42219 | 1014 | elif self.paramenc == "passthrough": |
6178061e PG |
1015 | self.enc = PassthroughCipher () |
1016 | else: | |
b12110dd PG |
1017 | raise InvalidParameter ("next: parameter version %d not known" |
1018 | % self.paramversion) | |
48db09ba PG |
1019 | hdrdum = hdr_make_dummy (filename) |
1020 | self.lastinfo = (filename, hdrdum) | |
30019abf | 1021 | super().next (self.password, self.paramversion, self.nacl, self.iv) |
72a42219 | 1022 | |
3031b7ae | 1023 | self.set_object_counter (self.cnt + 1) |
48db09ba | 1024 | return hdrdum |
a393d9cb | 1025 | |
a393d9cb | 1026 | |
cd77dadb | 1027 | def done (self, cmpdata): |
704ceaa5 PG |
1028 | """ |
1029 | Complete encryption of an object. After this has been called, attempts | |
1030 | of encrypting further data will cause an error until ``.next()`` is | |
1031 | invoked properly. | |
1032 | ||
1033 | Returns a 64 bytes buffer containing the object header including all | |
1034 | values including the “late” ones e. g. the ciphertext size and the | |
1035 | GCM tag. | |
1036 | """ | |
36b9932a PG |
1037 | if isinstance (cmpdata, bytes) is False: |
1038 | raise InvalidParameter ("done: comparison input expected as bytes, " | |
1039 | "not %s" % type (cmpdata)) | |
cb7a3911 PG |
1040 | if self.lastinfo is None: |
1041 | raise RuntimeError ("done: encryption context not initialized") | |
48db09ba PG |
1042 | filename, hdrdum = self.lastinfo |
1043 | if cmpdata != hdrdum: | |
b12110dd PG |
1044 | raise RuntimeError ("done: bad sync of header for object %d: " |
1045 | "preliminary data does not match; this likely " | |
1046 | "indicates a wrongly repositioned stream" | |
1047 | % self.cnt) | |
6178061e | 1048 | data = self.enc.finalize () |
633b18a9 | 1049 | self.stats ["out"] += len (data) |
cd77dadb | 1050 | self.ctsize += len (data) |
48db09ba PG |
1051 | ok, hdr = hdr_from_params (self.version, self.paramversion, self.nacl, |
1052 | self.iv, self.ctsize, self.enc.tag) | |
8a990744 | 1053 | if ok is False: |
b12110dd PG |
1054 | raise InternalError ("error constructing header: %r" % hdr) |
1055 | return data, hdr, self.fixed | |
a393d9cb | 1056 | |
a393d9cb | 1057 | |
cd77dadb | 1058 | def process (self, buf): |
704ceaa5 PG |
1059 | """ |
1060 | Encrypt a chunk of plaintext with the active encryptor. Returns the | |
1061 | size of the input consumed. This **must** be checked downstream. If the | |
1062 | maximum possible object size has been reached, the current context must | |
1063 | be finalized and a new one established before any further data can be | |
1064 | encrypted. The second argument is the remainder of the plaintext that | |
1065 | was not encrypted for the caller to use immediately after the new | |
1066 | context is ready. | |
1067 | """ | |
36b9932a PG |
1068 | if isinstance (buf, bytes) is False: |
1069 | raise InvalidParameter ("process: expected byte buffer, not %s" | |
1070 | % type (buf)) | |
cb7a3911 PG |
1071 | bsize = len (buf) |
1072 | newptsize = self.ptsize + bsize | |
1073 | diff = newptsize - PDTCRYPT_MAX_OBJ_SIZE | |
1074 | if diff > 0: | |
1075 | bsize -= diff | |
1076 | newptsize = PDTCRYPT_MAX_OBJ_SIZE | |
1077 | self.ptsize = newptsize | |
1078 | data = super().process (buf [:bsize]) | |
cd77dadb | 1079 | self.ctsize += len (data) |
cb7a3911 | 1080 | return bsize, data |
cd77dadb PG |
1081 | |
1082 | ||
39accaaa | 1083 | class Decrypt (Crypto): |
a393d9cb | 1084 | |
3031b7ae | 1085 | tag = None # GCM tag, part of header |
3031b7ae | 1086 | last_iv = None # check consecutive ivs in strict mode |
39accaaa | 1087 | |
1f3fd7b0 | 1088 | def __init__ (self, password=None, key=None, counter=None, fixedparts=None, |
ee6aa239 | 1089 | strict_ivs=False): |
704ceaa5 PG |
1090 | """ |
1091 | Sanitizing ctor for the decryption context. ``fixedparts`` specifies a | |
1092 | list of IV fixed parts accepted during decryption. If a fixed part is | |
1093 | encountered that is not in the list, decryption will fail. | |
1094 | ||
1095 | :param password: mutually exclusive with ``key`` | |
1096 | :type password: bytes | |
1097 | :param key: mutually exclusive with ``password`` | |
1098 | :type key: bytes | |
1099 | :type counter: initial object counter the values | |
1100 | ``AES_GCM_IV_CNT_INFOFILE`` and | |
1101 | ``AES_GCM_IV_CNT_INDEX`` are unique in each backup set | |
1102 | and cannot be reused even with different fixed parts. | |
1103 | :type fixedparts: bytes list | |
1104 | """ | |
1f3fd7b0 PG |
1105 | if password is None and key is None \ |
1106 | or password is not None and key is not None : | |
1107 | raise InvalidParameter ("__init__: need either key or password") | |
1108 | ||
1109 | if key is not None: | |
1110 | if isinstance (key, bytes) is False: | |
1111 | raise InvalidParameter ("__init__: key must be provided as " | |
1112 | "bytes, not %s" % type (key)) | |
1113 | else: # password, no key | |
1114 | if isinstance (password, str) is False: | |
1115 | raise InvalidParameter ("__init__: password must be a string, not %s" | |
1116 | % type (password)) | |
1117 | if len (password) == 0: | |
1118 | raise InvalidParameter ("__init__: supplied empty password but not " | |
1119 | "permitted for PDT encrypted files") | |
36b9932a | 1120 | # fixed parts |
50710d86 | 1121 | if fixedparts is not None: |
36b9932a PG |
1122 | if isinstance (fixedparts, list) is False: |
1123 | raise InvalidParameter ("__init__: IV fixed parts must be " | |
1124 | "supplied as list, not %s" | |
1125 | % type (fixedparts)) | |
b12110dd PG |
1126 | self.fixed = fixedparts |
1127 | self.fixed.sort () | |
ee6aa239 | 1128 | |
a83fa4ed PG |
1129 | super().__init__ (password=password, key=key, counter=counter, |
1130 | strict_ivs=strict_ivs) | |
39accaaa PG |
1131 | |
1132 | ||
b12110dd | 1133 | def valid_fixed_part (self, iv): |
704ceaa5 PG |
1134 | """ |
1135 | Check if a fixed part was already seen. | |
1136 | """ | |
50710d86 | 1137 | # check if fixed part is known |
b12110dd PG |
1138 | fixed, _cnt = struct.unpack (FMT_I2N_IV, iv) |
1139 | i = bisect.bisect_left (self.fixed, fixed) | |
1140 | return i != len (self.fixed) and self.fixed [i] == fixed | |
50710d86 PG |
1141 | |
1142 | ||
ee6aa239 | 1143 | def check_consecutive_iv (self, iv): |
704ceaa5 PG |
1144 | """ |
1145 | Check whether the counter part of the given IV is indeed the successor | |
1146 | of the currently present counter. This should always be the case for | |
1147 | the objects in a well formed PDT archive but should not be enforced | |
1148 | when decrypting out-of-order. | |
1149 | """ | |
ee6aa239 | 1150 | fixed, cnt = struct.unpack (FMT_I2N_IV, iv) |
3031b7ae PG |
1151 | if self.strict_ivs is True \ |
1152 | and self.last_iv is not None \ | |
ee6aa239 PG |
1153 | and self.last_iv [0] == fixed \ |
1154 | and self.last_iv [1] != cnt - 1: | |
f6cd676f | 1155 | raise NonConsecutiveIV ("iv %s counter not successor of " |
ee6aa239 | 1156 | "last object (expected %d, found %d)" |
f6cd676f | 1157 | % (iv_fmt (self.last_iv [1]), cnt)) |
ee6aa239 PG |
1158 | self.last_iv = (iv, cnt) |
1159 | ||
1160 | ||
79782fa9 | 1161 | def next (self, hdr): |
704ceaa5 PG |
1162 | """ |
1163 | Start decrypting the next object. The PDTCRYPT header for the object | |
1164 | can be given either as already parsed object or as bytes. | |
1165 | """ | |
dccfe104 PG |
1166 | if isinstance (hdr, bytes) is True: |
1167 | hdr = hdr_read (hdr) | |
36b9932a PG |
1168 | elif isinstance (hdr, dict) is False: |
1169 | # this won’t catch malformed specs though | |
1170 | raise InvalidParameter ("next: wrong type of parameter hdr: " | |
1171 | "expected bytes or spec, got %s" | |
fbfda3d4 | 1172 | % type (hdr)) |
36b9932a PG |
1173 | try: |
1174 | paramversion = hdr ["paramversion"] | |
1175 | nacl = hdr ["nacl"] | |
1176 | iv = hdr ["iv"] | |
1177 | tag = hdr ["tag"] | |
1178 | except KeyError: | |
1179 | raise InvalidHeader ("next: not a header %r" % hdr) | |
1180 | ||
30019abf | 1181 | super().next (self.password, paramversion, nacl, iv) |
b12110dd | 1182 | if self.fixed is not None and self.valid_fixed_part (iv) is False: |
f6cd676f PG |
1183 | raise InvalidIVFixedPart ("iv %s has invalid fixed part" |
1184 | % iv_fmt (iv)) | |
3031b7ae | 1185 | self.check_consecutive_iv (iv) |
ee6aa239 | 1186 | |
36b9932a | 1187 | self.tag = tag |
b12110dd PG |
1188 | defs = ENCRYPTION_PARAMETERS.get (paramversion, None) |
1189 | if defs is None: | |
1190 | raise FormatError ("header contains unknown parameter version %d; " | |
1191 | "maybe the file was created by a more recent " | |
1192 | "version of Deltatar" % paramversion) | |
50710d86 | 1193 | enc = defs ["enc"] |
6178061e PG |
1194 | if enc == "aes-gcm": |
1195 | self.enc = Cipher \ | |
1196 | ( algorithms.AES (self.key) | |
36b9932a | 1197 | , modes.GCM (iv, tag=self.tag) |
6178061e PG |
1198 | , backend = default_backend ()) \ |
1199 | . decryptor () | |
1200 | elif enc == "passthrough": | |
1201 | self.enc = PassthroughCipher () | |
1202 | else: | |
b12110dd PG |
1203 | raise InternalError ("encryption parameter set %d refers to unknown " |
1204 | "mode %r" % (paramversion, enc)) | |
f484f2d1 | 1205 | self.set_object_counter (self.cnt + 1) |
39accaaa PG |
1206 | |
1207 | ||
db1f3ac7 | 1208 | def done (self, tag=None): |
704ceaa5 PG |
1209 | """ |
1210 | Stop decryption of the current object and finalize it with the active | |
1211 | context. This will throw an *InvalidGCMTag* exception to indicate that | |
1212 | the authentication tag does not match the data. If the tag is correct, | |
1213 | the rest of the plaintext is returned. | |
1214 | """ | |
633b18a9 | 1215 | data = b"" |
db1f3ac7 PG |
1216 | try: |
1217 | if tag is None: | |
f484f2d1 | 1218 | data = self.enc.finalize () |
db1f3ac7 | 1219 | else: |
36b9932a PG |
1220 | if isinstance (tag, bytes) is False: |
1221 | raise InvalidParameter ("done: wrong type of parameter " | |
1222 | "tag: expected bytes, got %s" | |
1223 | % type (tag)) | |
f484f2d1 | 1224 | data = self.enc.finalize_with_tag (self.tag) |
b0078f26 | 1225 | except cryptography.exceptions.InvalidTag: |
f08c604b | 1226 | raise InvalidGCMTag ("done: tag mismatch of object %d: %s " |
b0078f26 | 1227 | "rejected by finalize ()" |
f08c604b | 1228 | % (self.cnt, binascii.hexlify (self.tag))) |
50710d86 | 1229 | self.ctsize += len (data) |
633b18a9 | 1230 | self.stats ["out"] += len (data) |
b0078f26 | 1231 | return data |
00b3cd10 PG |
1232 | |
1233 | ||
47e27926 | 1234 | def process (self, buf): |
704ceaa5 PG |
1235 | """ |
1236 | Decrypt the bytes object *buf* with the active decryptor. | |
1237 | """ | |
36b9932a PG |
1238 | if isinstance (buf, bytes) is False: |
1239 | raise InvalidParameter ("process: expected byte buffer, not %s" | |
1240 | % type (buf)) | |
47e27926 PG |
1241 | self.ctsize += len (buf) |
1242 | data = super().process (buf) | |
1243 | self.ptsize += len (data) | |
1244 | return data | |
1245 | ||
1246 | ||
00b3cd10 | 1247 | ############################################################################### |
770173c5 PG |
1248 | ## testing helpers |
1249 | ############################################################################### | |
1250 | ||
cb7a3911 | 1251 | def _patch_global (glob, vow, n=None): |
770173c5 PG |
1252 | """ |
1253 | Adapt upper file counter bound for testing IV logic. Completely unsafe. | |
1254 | """ | |
1255 | assert vow == "I am fully aware that this will void my warranty." | |
cb7a3911 PG |
1256 | r = globals () [glob] |
1257 | if n is None: | |
1258 | n = globals () [glob + "_DEFAULT"] | |
1259 | globals () [glob] = n | |
770173c5 PG |
1260 | return r |
1261 | ||
cb7a3911 PG |
1262 | _testing_set_AES_GCM_IV_CNT_MAX = \ |
1263 | partial (_patch_global, "AES_GCM_IV_CNT_MAX") | |
1264 | ||
1265 | _testing_set_PDTCRYPT_MAX_OBJ_SIZE = \ | |
1266 | partial (_patch_global, "PDTCRYPT_MAX_OBJ_SIZE") | |
1267 | ||
770173c5 | 1268 | ############################################################################### |
00b3cd10 PG |
1269 | ## freestanding invocation |
1270 | ############################################################################### | |
1271 | ||
da82bc58 PG |
1272 | PDTCRYPT_SUB_PROCESS = 0 |
1273 | PDTCRYPT_SUB_SCRYPT = 1 | |
f41973a6 | 1274 | PDTCRYPT_SUB_SCAN = 2 |
da82bc58 PG |
1275 | |
1276 | PDTCRYPT_SUB = \ | |
1277 | { "process" : PDTCRYPT_SUB_PROCESS | |
f41973a6 PG |
1278 | , "scrypt" : PDTCRYPT_SUB_SCRYPT |
1279 | , "scan" : PDTCRYPT_SUB_SCAN } | |
da82bc58 | 1280 | |
a83fa4ed PG |
1281 | PDTCRYPT_SECRET_PW = 0 |
1282 | PDTCRYPT_SECRET_KEY = 1 | |
1283 | ||
e3abcdf0 PG |
1284 | PDTCRYPT_DECRYPT = 1 << 0 # decrypt archive with password |
1285 | PDTCRYPT_SPLIT = 1 << 1 # split archive into individual objects | |
da82bc58 | 1286 | PDTCRYPT_HASH = 1 << 2 # output scrypt hash for file and given password |
e3abcdf0 PG |
1287 | |
1288 | PDTCRYPT_SPLITNAME = "pdtcrypt-object-%d.bin" | |
1289 | ||
70ad9458 | 1290 | PDTCRYPT_VERBOSE = False |
ee6aa239 | 1291 | PDTCRYPT_STRICTIVS = False |
b07633d3 | 1292 | PDTCRYPT_OVERWRITE = False |
15d3eefd | 1293 | PDTCRYPT_BLOCKSIZE = 1 << 12 |
70ad9458 PG |
1294 | PDTCRYPT_SINK = 0 |
1295 | PDTCRYPT_SOURCE = 1 | |
1296 | SELF = None | |
1297 | ||
77058bab PG |
1298 | PDTCRYPT_DEFAULT_VER = 1 |
1299 | PDTCRYPT_DEFAULT_PVER = 1 | |
1300 | ||
7b3940e5 PG |
1301 | # scrypt hashing output control |
1302 | PDTCRYPT_SCRYPT_INTRANATOR = 0 | |
1303 | PDTCRYPT_SCRYPT_PARAMETERS = 1 | |
4f6405d6 | 1304 | PDTCRYPT_SCRYPT_DEFAULT = PDTCRYPT_SCRYPT_INTRANATOR |
7b3940e5 PG |
1305 | |
1306 | PDTCRYPT_SCRYPT_FORMAT = \ | |
1307 | { "i2n" : PDTCRYPT_SCRYPT_INTRANATOR | |
1308 | , "params" : PDTCRYPT_SCRYPT_PARAMETERS } | |
1309 | ||
4c62ddc0 | 1310 | PDTCRYPT_TT_COLUMNS = 80 # assume standard terminal |
15d3eefd PG |
1311 | |
1312 | class PDTDecryptionError (Exception): | |
1313 | """Decryption failed.""" | |
1314 | ||
e3abcdf0 PG |
1315 | class PDTSplitError (Exception): |
1316 | """Decryption failed.""" | |
1317 | ||
15d3eefd PG |
1318 | |
1319 | def noise (*a, **b): | |
591a722f | 1320 | print (file=sys.stderr, *a, **b) |
15d3eefd PG |
1321 | |
1322 | ||
89e1073c PG |
1323 | class PassthroughDecryptor (object): |
1324 | ||
1325 | curhdr = None # write current header on first data write | |
1326 | ||
1327 | def __init__ (self): | |
1328 | if PDTCRYPT_VERBOSE is True: | |
1329 | noise ("PDT: no encryption; data passthrough") | |
1330 | ||
1331 | def next (self, hdr): | |
1332 | ok, curhdr = hdr_make (hdr) | |
1333 | if ok is False: | |
1334 | raise PDTDecryptionError ("bad header %r" % hdr) | |
1335 | self.curhdr = curhdr | |
1336 | ||
1337 | def done (self): | |
1338 | if self.curhdr is not None: | |
1339 | return self.curhdr | |
1340 | return b"" | |
1341 | ||
1342 | def process (self, d): | |
1343 | if self.curhdr is not None: | |
1344 | d = self.curhdr + d | |
1345 | self.curhdr = None | |
1346 | return d | |
1347 | ||
1348 | ||
a83fa4ed | 1349 | def depdtcrypt (mode, secret, ins, outs): |
15d3eefd | 1350 | """ |
a83fa4ed PG |
1351 | Remove PDTCRYPT layer from all objects encrypted with the secret. Used on a |
1352 | Deltatar backup this will yield a (possibly Gzip compressed) tarball. | |
15d3eefd PG |
1353 | """ |
1354 | ctleft = -1 # length of ciphertext to consume | |
1355 | ctcurrent = 0 # total ciphertext of current object | |
15d3eefd PG |
1356 | total_obj = 0 # total number of objects read |
1357 | total_pt = 0 # total plaintext bytes | |
1358 | total_ct = 0 # total ciphertext bytes | |
1359 | total_read = 0 # total bytes read | |
e3abcdf0 PG |
1360 | outfile = None # Python file object for output |
1361 | ||
89e1073c | 1362 | if mode & PDTCRYPT_DECRYPT: # decryptor |
a83fa4ed PG |
1363 | ks = secret [0] |
1364 | if ks == PDTCRYPT_SECRET_PW: | |
1365 | decr = Decrypt (password=secret [1], strict_ivs=PDTCRYPT_STRICTIVS) | |
1366 | elif ks == PDTCRYPT_SECRET_KEY: | |
1367 | key = binascii.unhexlify (secret [1]) | |
1368 | decr = Decrypt (key=key, strict_ivs=PDTCRYPT_STRICTIVS) | |
1369 | else: | |
1370 | raise InternalError ("‘%d’ does not specify a valid kind of secret" | |
1371 | % ks) | |
89e1073c PG |
1372 | else: |
1373 | decr = PassthroughDecryptor () | |
1374 | ||
e3abcdf0 PG |
1375 | def nextout (_): |
1376 | """Dummy for non-split mode: output file does not vary.""" | |
1377 | return outs | |
1378 | ||
1379 | if mode & PDTCRYPT_SPLIT: | |
1380 | def nextout (outfile): | |
1381 | """ | |
1382 | We were passed an fd as outs for accessing the destination | |
1383 | directory where extracted archive components are supposed | |
1384 | to end up in. | |
1385 | """ | |
1386 | ||
1387 | if outfile is None: | |
1388 | if PDTCRYPT_VERBOSE is True: | |
1389 | noise ("PDT: no output file to close at this point") | |
77058bab PG |
1390 | else: |
1391 | if PDTCRYPT_VERBOSE is True: | |
1392 | noise ("PDT: release output file %r" % outfile) | |
e3abcdf0 PG |
1393 | # cleanup happens automatically by the GC; the next |
1394 | # line will error out on account of an invalid fd | |
1395 | #outfile.close () | |
1396 | ||
1397 | assert total_obj > 0 | |
1398 | fname = PDTCRYPT_SPLITNAME % total_obj | |
1399 | try: | |
b07633d3 PG |
1400 | oflags = os.O_CREAT | os.O_WRONLY |
1401 | if PDTCRYPT_OVERWRITE is True: | |
1402 | oflags |= os.O_TRUNC | |
1403 | else: | |
1404 | oflags |= os.O_EXCL | |
1405 | outfd = os.open (fname, oflags, 0o600, dir_fd=outs) | |
e3abcdf0 PG |
1406 | if PDTCRYPT_VERBOSE is True: |
1407 | noise ("PDT: new output file %s → %d" % (fname, outfd)) | |
1408 | except FileExistsError as exn: | |
1409 | noise ("PDT: refusing to overwrite existing file %s" % fname) | |
1410 | noise ("") | |
1411 | raise PDTSplitError ("destination file %s already exists" | |
1412 | % fname) | |
1413 | ||
1414 | return os.fdopen (outfd, "wb", closefd=True) | |
1415 | ||
15d3eefd | 1416 | |
47d22679 | 1417 | def tell (s): |
b09a99eb | 1418 | """ESPIPE is normal on non-seekable stdio stream.""" |
47d22679 PG |
1419 | try: |
1420 | return s.tell () | |
1421 | except OSError as exn: | |
b09a99eb | 1422 | if exn.errno == os.errno.ESPIPE: |
47d22679 PG |
1423 | return -1 |
1424 | ||
e3abcdf0 | 1425 | def out (pt, outfile): |
15d3eefd PG |
1426 | npt = len (pt) |
1427 | nonlocal total_pt | |
1428 | total_pt += npt | |
70ad9458 | 1429 | if PDTCRYPT_VERBOSE is True: |
15d3eefd PG |
1430 | noise ("PDT:\t· decrypt plaintext %d B" % (npt)) |
1431 | try: | |
e3abcdf0 | 1432 | nn = outfile.write (pt) |
15d3eefd PG |
1433 | except OSError as exn: # probably ENOSPC |
1434 | raise DecryptionError ("error (%s)" % exn) | |
1435 | if nn != npt: | |
1436 | raise DecryptionError ("write aborted after %d of %d B" % (nn, npt)) | |
1437 | ||
1438 | while True: | |
1439 | if ctleft <= 0: | |
1440 | # current object completed; in a valid archive this marks either | |
1441 | # the start of a new header or the end of the input | |
1442 | if ctleft == 0: # current object requires finalization | |
70ad9458 | 1443 | if PDTCRYPT_VERBOSE is True: |
47d22679 | 1444 | noise ("PDT: %d finalize" % tell (ins)) |
5d394c0d PG |
1445 | try: |
1446 | pt = decr.done () | |
1447 | except InvalidGCMTag as exn: | |
f08c604b PG |
1448 | raise DecryptionError ("error finalizing object %d (%d B): " |
1449 | "%r" % (total_obj, len (pt), exn)) \ | |
1450 | from exn | |
e3abcdf0 | 1451 | out (pt, outfile) |
70ad9458 | 1452 | if PDTCRYPT_VERBOSE is True: |
15d3eefd PG |
1453 | noise ("PDT:\t· object validated") |
1454 | ||
70ad9458 | 1455 | if PDTCRYPT_VERBOSE is True: |
47d22679 | 1456 | noise ("PDT: %d hdr" % tell (ins)) |
15d3eefd PG |
1457 | try: |
1458 | hdr = hdr_read_stream (ins) | |
dd47d6a2 | 1459 | total_read += PDTCRYPT_HDR_SIZE |
ae3d0f2a PG |
1460 | except EndOfFile as exn: |
1461 | total_read += exn.remainder | |
dd47d6a2 | 1462 | if total_ct + total_obj * PDTCRYPT_HDR_SIZE != total_read: |
15d3eefd PG |
1463 | raise PDTDecryptionError ("ciphertext processed (%d B) plus " |
1464 | "overhead (%d × %d B) does not match " | |
1465 | "the number of bytes read (%d )" | |
dd47d6a2 | 1466 | % (total_ct, total_obj, PDTCRYPT_HDR_SIZE, |
15d3eefd PG |
1467 | total_read)) |
1468 | # the single good exit | |
1469 | return total_read, total_obj, total_ct, total_pt | |
1470 | except InvalidHeader as exn: | |
1471 | raise PDTDecryptionError ("invalid header at position %d in %r " | |
ee6aa239 | 1472 | "(%s)" % (tell (ins), exn, ins)) |
70ad9458 | 1473 | if PDTCRYPT_VERBOSE is True: |
15d3eefd PG |
1474 | pretty = hdr_fmt_pretty (hdr) |
1475 | noise (reduce (lambda a, e: (a + "\n" if a else "") + "PDT:\t· " + e, | |
1476 | pretty.splitlines (), "")) | |
1477 | ctcurrent = ctleft = hdr ["ctsize"] | |
89e1073c | 1478 | |
15d3eefd | 1479 | decr.next (hdr) |
e3abcdf0 PG |
1480 | |
1481 | total_obj += 1 # used in file counter with split mode | |
1482 | ||
1483 | # finalization complete or skipped in case of first object in | |
1484 | # stream; create a new output file if necessary | |
1485 | outfile = nextout (outfile) | |
15d3eefd | 1486 | |
70ad9458 | 1487 | if PDTCRYPT_VERBOSE is True: |
15d3eefd | 1488 | noise ("PDT: %d decrypt obj no. %d, %d B" |
47d22679 | 1489 | % (tell (ins), total_obj, ctleft)) |
15d3eefd PG |
1490 | |
1491 | # always allocate a new buffer since python-cryptography doesn’t allow | |
1492 | # passing a bytearray :/ | |
1493 | nexpect = min (ctleft, PDTCRYPT_BLOCKSIZE) | |
70ad9458 | 1494 | if PDTCRYPT_VERBOSE is True: |
15d3eefd | 1495 | noise ("PDT:\t· [%d] %d%% done, read block (%d B of %d B remaining)" |
47d22679 | 1496 | % (tell (ins), |
15d3eefd PG |
1497 | 100 - ctleft * 100 / (ctcurrent > 0 and ctcurrent or 1), |
1498 | nexpect, ctleft)) | |
1499 | ct = ins.read (nexpect) | |
1500 | nct = len (ct) | |
1501 | if nct < nexpect: | |
47d22679 | 1502 | off = tell (ins) |
ae3d0f2a PG |
1503 | raise EndOfFile (nct, |
1504 | "hit EOF after %d of %d B in block [%d:%d); " | |
15d3eefd PG |
1505 | "%d B ciphertext remaining for object no %d" |
1506 | % (nct, nexpect, off, off + nexpect, ctleft, | |
1507 | total_obj)) | |
1508 | ctleft -= nct | |
1509 | total_ct += nct | |
1510 | total_read += nct | |
1511 | ||
70ad9458 | 1512 | if PDTCRYPT_VERBOSE is True: |
15d3eefd PG |
1513 | noise ("PDT:\t· decrypt ciphertext %d B" % (nct)) |
1514 | pt = decr.process (ct) | |
e3abcdf0 | 1515 | out (pt, outfile) |
15d3eefd | 1516 | |
d6c15a52 | 1517 | |
70ad9458 | 1518 | def deptdcrypt_mk_stream (kind, path): |
d6c15a52 | 1519 | """Create stream from file or stdio descriptor.""" |
70ad9458 | 1520 | if kind == PDTCRYPT_SINK: |
d6c15a52 | 1521 | if path == "-": |
70ad9458 | 1522 | if PDTCRYPT_VERBOSE is True: noise ("PDT: sink: stdout") |
d6c15a52 PG |
1523 | return sys.stdout.buffer |
1524 | else: | |
70ad9458 | 1525 | if PDTCRYPT_VERBOSE is True: noise ("PDT: sink: file %s" % path) |
d6c15a52 | 1526 | return io.FileIO (path, "w") |
70ad9458 | 1527 | if kind == PDTCRYPT_SOURCE: |
d6c15a52 | 1528 | if path == "-": |
70ad9458 | 1529 | if PDTCRYPT_VERBOSE is True: noise ("PDT: source: stdin") |
d6c15a52 PG |
1530 | return sys.stdin.buffer |
1531 | else: | |
70ad9458 | 1532 | if PDTCRYPT_VERBOSE is True: noise ("PDT: source: file %s" % path) |
d6c15a52 PG |
1533 | return io.FileIO (path, "r") |
1534 | ||
1535 | raise ValueError ("bogus stream “%s” / %s" % (kind, path)) | |
1536 | ||
15d3eefd | 1537 | |
a83fa4ed | 1538 | def mode_depdtcrypt (mode, secret, ins, outs): |
da82bc58 PG |
1539 | try: |
1540 | total_read, total_obj, total_ct, total_pt = \ | |
a83fa4ed | 1541 | depdtcrypt (mode, secret, ins, outs) |
da82bc58 PG |
1542 | except DecryptionError as exn: |
1543 | noise ("PDT: Decryption failed:") | |
1544 | noise ("PDT:") | |
1545 | noise ("PDT: “%s”" % exn) | |
1546 | noise ("PDT:") | |
a83fa4ed | 1547 | noise ("PDT: Did you specify the correct key / password?") |
da82bc58 PG |
1548 | noise ("") |
1549 | return 1 | |
1550 | except PDTSplitError as exn: | |
1551 | noise ("PDT: Split operation failed:") | |
1552 | noise ("PDT:") | |
1553 | noise ("PDT: “%s”" % exn) | |
1554 | noise ("PDT:") | |
a83fa4ed | 1555 | noise ("PDT: Hint: target directory should be empty.") |
da82bc58 PG |
1556 | noise ("") |
1557 | return 1 | |
1558 | ||
1559 | if PDTCRYPT_VERBOSE is True: | |
1560 | noise ("PDT: decryption successful" ) | |
1561 | noise ("PDT: %.10d bytes read" % total_read) | |
1562 | noise ("PDT: %.10d objects decrypted" % total_obj ) | |
1563 | noise ("PDT: %.10d bytes ciphertext" % total_ct ) | |
1564 | noise ("PDT: %.10d bytes plaintext" % total_pt ) | |
1565 | noise ("" ) | |
1566 | ||
1567 | return 0 | |
1568 | ||
1569 | ||
7b3940e5 | 1570 | def mode_scrypt (pw, ins=None, nacl=None, fmt=PDTCRYPT_SCRYPT_INTRANATOR): |
77058bab | 1571 | hsh = None |
7b3940e5 | 1572 | paramversion = PDTCRYPT_DEFAULT_PVER |
77058bab PG |
1573 | if ins is not None: |
1574 | hsh, nacl, version, paramversion = scrypt_hashsource (pw, ins) | |
1575 | defs = ENCRYPTION_PARAMETERS.get(paramversion, None) | |
1576 | else: | |
1577 | nacl = binascii.unhexlify (nacl) | |
7b3940e5 | 1578 | defs = ENCRYPTION_PARAMETERS.get(paramversion, None) |
77058bab PG |
1579 | version = PDTCRYPT_DEFAULT_VER |
1580 | ||
1581 | kdfname, params = defs ["kdf"] | |
1582 | if hsh is None: | |
1583 | kdf = kdf_by_version (None, defs) | |
1584 | hsh, _void = kdf (pw, nacl) | |
da82bc58 PG |
1585 | |
1586 | import json | |
7b3940e5 PG |
1587 | |
1588 | if fmt == PDTCRYPT_SCRYPT_INTRANATOR: | |
1589 | out = json.dumps ({ "salt" : base64.b64encode (nacl).decode () | |
1590 | , "key" : base64.b64encode (hsh) .decode () | |
1591 | , "paramversion" : paramversion }) | |
1592 | elif fmt == PDTCRYPT_SCRYPT_PARAMETERS: | |
1593 | out = json.dumps ({ "salt" : binascii.hexlify (nacl).decode () | |
1594 | , "key" : binascii.hexlify (hsh) .decode () | |
1595 | , "version" : version | |
1596 | , "scrypt_params" : { "N" : params ["N"] | |
1597 | , "r" : params ["r"] | |
1598 | , "p" : params ["p"] | |
1599 | , "dkLen" : params ["dkLen"] } }) | |
1600 | else: | |
1601 | raise RuntimeError ("bad scrypt output scheme %r" % fmt) | |
1602 | ||
da82bc58 PG |
1603 | print (out) |
1604 | ||
1605 | ||
4c62ddc0 PG |
1606 | def noise_output_candidates (cands, indent=8, cols=PDTCRYPT_TT_COLUMNS): |
1607 | """ | |
1608 | Print a list of offsets without garbling the terminal too much. | |
1609 | ||
1610 | The indent is counted from column zero; if it is wide enough, the “PDT: ” | |
1611 | marker will be prepended, considered part of the indentation. | |
1612 | """ | |
1613 | wd = cols - 1 | |
1614 | nc = len (cands) | |
1615 | idt = " " * indent if indent < 5 else "PDT: " + " " * (indent - 5) | |
1616 | line = idt | |
1617 | lpos = indent | |
1618 | sep = "," | |
1619 | lsep = len (sep) | |
1620 | init = True # prevent leading separator | |
1621 | ||
1622 | if indent >= wd: | |
1623 | raise ValueError ("the requested indentation exceeds the line " | |
1624 | "width by %d" % (indent - wd)) | |
1625 | ||
1626 | for n in cands: | |
1627 | ns = "%d" % n | |
1628 | lns = len (ns) | |
1629 | if init is False: | |
1630 | line += sep | |
1631 | lpos += lsep | |
1632 | ||
1633 | lpos += lns | |
1634 | if lpos > wd: # line break | |
1635 | noise (line) | |
1636 | line = idt | |
1637 | lpos = indent + lns | |
1638 | elif init is True: | |
1639 | init = False | |
1640 | else: # space | |
1641 | line += ' ' | |
1642 | lpos += 1 | |
1643 | ||
1644 | line += ns | |
1645 | ||
1646 | if lpos != indent: | |
1647 | noise (line) | |
1648 | ||
1649 | ||
f41973a6 PG |
1650 | def mode_scan (pw, fname, nacl=None): |
1651 | """ | |
1652 | Dissect a binary file, looking for PDTCRYPT headers and objects. | |
1653 | """ | |
1654 | try: | |
1655 | fd = os.open (fname, os.O_RDONLY) | |
1656 | except FileNotFoundError: | |
1657 | noise ("PDT: failed to open %s readonly" % fname) | |
1658 | noise ("") | |
1659 | usage (err=True) | |
1660 | ||
1661 | try: | |
1662 | if PDTCRYPT_VERBOSE is True: | |
1663 | noise ("PDT: scan for potential sync points") | |
1664 | cands = locate_hdr_candidates (fd) | |
1665 | if len (cands) == 0: | |
1666 | noise ("PDT: scan complete: input does not contain potential PDT " | |
1667 | "headers; giving up.") | |
1668 | return -1 | |
1669 | if PDTCRYPT_VERBOSE is True: | |
4c62ddc0 PG |
1670 | noise ("PDT: scan complete: found %d candidates:" % len (cands)) |
1671 | noise_output_candidates (cands) | |
f41973a6 PG |
1672 | finally: |
1673 | os.close (fd) | |
1674 | ||
7b3940e5 | 1675 | |
70ad9458 PG |
1676 | def usage (err=False): |
1677 | out = print | |
1678 | if err is True: | |
1679 | out = noise | |
5afcb45d | 1680 | indent = ' ' * len (SELF) |
da82bc58 | 1681 | out ("usage: %s SUBCOMMAND { --help" % SELF) |
5afcb45d | 1682 | out (" %s | [ -v ] { -p PASSWORD | -k KEY }" % indent) |
77058bab PG |
1683 | out (" %s [ { -i | --in } { - | SOURCE } ]" % indent) |
1684 | out (" %s [ { -n | --nacl } { SALT } ]" % indent) | |
1685 | out (" %s [ { -o | --out } { - | DESTINATION } ]" % indent) | |
1686 | out (" %s [ -D | --no-decrypt ] [ -S | --split ]" % indent) | |
7b3940e5 | 1687 | out (" %s [ -f | --format ]" % indent) |
70ad9458 PG |
1688 | out ("") |
1689 | out ("\twhere") | |
da82bc58 PG |
1690 | out ("\t\tSUBCOMMAND main mode: { process | scrypt }") |
1691 | out ("\t\t where:") | |
1692 | out ("\t\t process: extract objects from PDT archive") | |
1693 | out ("\t\t scrypt: calculate hash from password and first object") | |
a83fa4ed PG |
1694 | out ("\t\t-p PASSWORD password to derive the encryption key from") |
1695 | out ("\t\t-k KEY encryption key as 16 bytes in hexadecimal notation") | |
e3abcdf0 | 1696 | out ("\t\t-s enforce strict handling of initialization vectors") |
70ad9458 PG |
1697 | out ("\t\t-i SOURCE file name to read from") |
1698 | out ("\t\t-o DESTINATION file to write output to") | |
77058bab | 1699 | out ("\t\t-n SALT provide salt for scrypt mode in hex encoding") |
70ad9458 | 1700 | out ("\t\t-v print extra info") |
e3abcdf0 PG |
1701 | out ("\t\t-S split into files at object boundaries; this") |
1702 | out ("\t\t requires DESTINATION to refer to directory") | |
1703 | out ("\t\t-D PDT header and ciphertext passthrough") | |
7b3940e5 | 1704 | out ("\t\t-f format of SCRYPT hash output (“default” or “parameters”)") |
70ad9458 PG |
1705 | out ("") |
1706 | out ("\tinstead of filenames, “-” may used to specify stdin / stdout") | |
1707 | out ("") | |
1708 | sys.exit ((err is True) and 42 or 0) | |
1709 | ||
1710 | ||
a83fa4ed PG |
1711 | def bail (msg): |
1712 | noise (msg) | |
1713 | noise ("") | |
1714 | usage (err=True) | |
1715 | raise Unreachable | |
1716 | ||
1717 | ||
70ad9458 PG |
1718 | def parse_argv (argv): |
1719 | global SELF | |
7b3940e5 PG |
1720 | mode = PDTCRYPT_DECRYPT |
1721 | secret = None | |
1722 | insspec = None | |
1723 | outsspec = None | |
1724 | nacl = None | |
4f6405d6 | 1725 | scrypt_format = PDTCRYPT_SCRYPT_DEFAULT |
70ad9458 PG |
1726 | |
1727 | argvi = iter (argv) | |
1728 | SELF = os.path.basename (next (argvi)) | |
1729 | ||
da82bc58 PG |
1730 | try: |
1731 | rawsubcmd = next (argvi) | |
1732 | subcommand = PDTCRYPT_SUB [rawsubcmd] | |
1733 | except StopIteration: | |
a83fa4ed | 1734 | bail ("ERROR: subcommand required") |
da82bc58 | 1735 | except KeyError: |
a83fa4ed | 1736 | bail ("ERROR: invalid subcommand “%s” specified" % rawsubcmd) |
da82bc58 | 1737 | |
59d74e2b PG |
1738 | def checked_arg (): |
1739 | nonlocal argvi | |
1740 | try: | |
1741 | return next (argvi) | |
1742 | except StopIteration: | |
1743 | bail ("ERROR: argument list incomplete") | |
1744 | ||
a83fa4ed PG |
1745 | def checked_secret (t, arg): |
1746 | nonlocal secret | |
1747 | if secret is None: | |
1748 | secret = (t, arg) | |
da82bc58 | 1749 | else: |
a83fa4ed | 1750 | bail ("ERROR: encountered “%s” but secret already given" % arg) |
da82bc58 | 1751 | |
70ad9458 PG |
1752 | for arg in argvi: |
1753 | if arg in [ "-h", "--help" ]: | |
1754 | usage () | |
1755 | raise Unreachable | |
1756 | elif arg in [ "-v", "--verbose", "--wtf" ]: | |
1757 | global PDTCRYPT_VERBOSE | |
1758 | PDTCRYPT_VERBOSE = True | |
1759 | elif arg in [ "-i", "--in", "--source" ]: | |
59d74e2b | 1760 | insspec = checked_arg () |
70ad9458 | 1761 | if PDTCRYPT_VERBOSE is True: noise ("PDT: decrypt from %s" % insspec) |
a83fa4ed | 1762 | elif arg in [ "-p", "--password" ]: |
59d74e2b | 1763 | arg = checked_arg () |
a83fa4ed PG |
1764 | checked_secret (PDTCRYPT_SECRET_PW, arg) |
1765 | if PDTCRYPT_VERBOSE is True: noise ("PDT: decrypting with password") | |
70ad9458 | 1766 | else: |
da82bc58 PG |
1767 | if subcommand == PDTCRYPT_SUB_PROCESS: |
1768 | if arg in [ "-s", "--strict-ivs" ]: | |
1769 | global PDTCRYPT_STRICTIVS | |
1770 | PDTCRYPT_STRICTIVS = True | |
77058bab PG |
1771 | elif arg in [ "-o", "--out", "--dest", "--sink" ]: |
1772 | outsspec = checked_arg () | |
1773 | if PDTCRYPT_VERBOSE is True: noise ("PDT: decrypt to %s" % outsspec) | |
da82bc58 PG |
1774 | elif arg in [ "-f", "--force" ]: |
1775 | global PDTCRYPT_OVERWRITE | |
1776 | PDTCRYPT_OVERWRITE = True | |
1777 | if PDTCRYPT_VERBOSE is True: noise ("PDT: overwrite existing files") | |
1778 | elif arg in [ "-S", "--split" ]: | |
1779 | mode |= PDTCRYPT_SPLIT | |
1780 | if PDTCRYPT_VERBOSE is True: noise ("PDT: split files") | |
1781 | elif arg in [ "-D", "--no-decrypt" ]: | |
1782 | mode &= ~PDTCRYPT_DECRYPT | |
1783 | if PDTCRYPT_VERBOSE is True: noise ("PDT: not decrypting") | |
a83fa4ed | 1784 | elif arg in [ "-k", "--key" ]: |
59d74e2b | 1785 | arg = checked_arg () |
a83fa4ed PG |
1786 | checked_secret (PDTCRYPT_SECRET_KEY, arg) |
1787 | if PDTCRYPT_VERBOSE is True: noise ("PDT: decrypting with key") | |
da82bc58 | 1788 | else: |
a83fa4ed | 1789 | bail ("ERROR: unexpected positional argument “%s”" % arg) |
da82bc58 | 1790 | elif subcommand == PDTCRYPT_SUB_SCRYPT: |
77058bab PG |
1791 | if arg in [ "-n", "--nacl", "--salt" ]: |
1792 | nacl = checked_arg () | |
1793 | if PDTCRYPT_VERBOSE is True: noise ("PDT: salt key with %s" % nacl) | |
7b3940e5 PG |
1794 | elif arg in [ "-f", "--format" ]: |
1795 | arg = checked_arg () | |
1796 | try: | |
1797 | scrypt_format = PDTCRYPT_SCRYPT_FORMAT [arg] | |
1798 | except KeyError: | |
1799 | bail ("ERROR: invalid scrypt output format %s" % arg) | |
1800 | if PDTCRYPT_VERBOSE is True: | |
1801 | noise ("PDT: scrypt output format “%s”" % scrypt_format) | |
77058bab PG |
1802 | else: |
1803 | bail ("ERROR: unexpected positional argument “%s”" % arg) | |
f41973a6 PG |
1804 | elif subcommand == PDTCRYPT_SUB_SCAN: |
1805 | pass | |
70ad9458 | 1806 | |
a83fa4ed | 1807 | if secret is None: |
ecb9676d | 1808 | if PDTCRYPT_VERBOSE is True: |
a83fa4ed | 1809 | noise ("ERROR: no password or key specified, trying $PDTCRYPT_PASSWORD") |
ecb9676d PG |
1810 | epw = os.getenv ("PDTCRYPT_PASSWORD") |
1811 | if epw is not None: | |
a83fa4ed PG |
1812 | checked_secret (PDTCRYPT_SECRET_PW, epw.strip ()) |
1813 | ||
1814 | if secret is None: | |
1815 | if PDTCRYPT_VERBOSE is True: | |
1816 | noise ("ERROR: no password or key specified, trying $PDTCRYPT_KEY") | |
1817 | ek = os.getenv ("PDTCRYPT_KEY") | |
1818 | if ek is not None: | |
1819 | checked_secret (PDTCRYPT_SECRET_KEY, ek.strip ()) | |
ecb9676d | 1820 | |
a83fa4ed | 1821 | if secret is None: |
da82bc58 | 1822 | if subcommand == PDTCRYPT_SUB_SCRYPT: |
a83fa4ed | 1823 | bail ("ERROR: scrypt hash mode requested but no password given") |
da82bc58 | 1824 | elif mode & PDTCRYPT_DECRYPT: |
a83fa4ed PG |
1825 | bail ("ERROR: encryption requested but no password given") |
1826 | ||
f41973a6 PG |
1827 | if subcommand == PDTCRYPT_SUB_SCAN: |
1828 | if insspec is None: | |
1829 | bail ("ERROR: please supply an input file for scanning") | |
1830 | if insspec == '-': | |
1831 | bail ("ERROR: input must be seekable; please specify a file") | |
1832 | return True, partial (mode_scan, secret [1].encode (), insspec, nacl) | |
1833 | ||
77058bab PG |
1834 | if subcommand == PDTCRYPT_SUB_SCRYPT: |
1835 | if secret [0] == PDTCRYPT_SECRET_KEY: | |
1836 | bail ("ERROR: scrypt mode requires a password") | |
1837 | if insspec is not None and nacl is not None \ | |
1838 | or insspec is None and nacl is None : | |
1839 | bail ("ERROR: please supply either an input file or " | |
1840 | "the salt") | |
70ad9458 PG |
1841 | |
1842 | # default to stdout | |
77058bab PG |
1843 | ins = None |
1844 | if insspec is not None or subcommand != PDTCRYPT_SUB_SCRYPT: | |
1845 | ins = deptdcrypt_mk_stream (PDTCRYPT_SOURCE, insspec or "-") | |
da82bc58 PG |
1846 | |
1847 | if subcommand == PDTCRYPT_SUB_SCRYPT: | |
7b3940e5 PG |
1848 | return True, partial (mode_scrypt, secret [1].encode (), ins, nacl, |
1849 | fmt=scrypt_format) | |
da82bc58 | 1850 | |
e3abcdf0 PG |
1851 | if mode & PDTCRYPT_SPLIT: # destination must be directory |
1852 | if outsspec is None or outsspec == "-": | |
a83fa4ed | 1853 | bail ("ERROR: split mode is incompatible with stdout sink") |
e3abcdf0 PG |
1854 | |
1855 | try: | |
1856 | try: | |
1857 | os.makedirs (outsspec, 0o700) | |
1858 | except FileExistsError: | |
1859 | # if it’s a directory with appropriate perms, everything is | |
1860 | # good; otherwise, below invocation of open(2) will fail | |
1861 | pass | |
1862 | outs = os.open (outsspec, os.O_DIRECTORY, 0o600) | |
1863 | except FileNotFoundError as exn: | |
a83fa4ed | 1864 | bail ("ERROR: cannot create target directory “%s”" % outsspec) |
e3abcdf0 | 1865 | except NotADirectoryError as exn: |
a83fa4ed | 1866 | bail ("ERROR: target path “%s” is not a directory" % outsspec) |
da82bc58 | 1867 | |
e3abcdf0 | 1868 | else: |
89e1073c | 1869 | outs = deptdcrypt_mk_stream (PDTCRYPT_SINK, outsspec or "-") |
da82bc58 | 1870 | |
a83fa4ed | 1871 | return True, partial (mode_depdtcrypt, mode, secret, ins, outs) |
15d3eefd PG |
1872 | |
1873 | ||
00b3cd10 | 1874 | def main (argv): |
da82bc58 | 1875 | ok, runner = parse_argv (argv) |
f08c604b | 1876 | |
da82bc58 | 1877 | if ok is True: return runner () |
15d3eefd | 1878 | |
da82bc58 | 1879 | return 1 |
f08c604b | 1880 | |
00b3cd10 PG |
1881 | |
1882 | if __name__ == "__main__": | |
1883 | sys.exit (main (sys.argv)) | |
1884 |