def _corrupt_crypttext_hash_tree_byte_x221(data, debug=False):
"""Scramble the file data -- the byte at offset 0x221 will have its 7th
(b1) bit flipped.
"""
sharevernum = struct.unpack(">L", data[0x0c:0x0c + 4])[0]
assert sharevernum in (
1, 2
), "This test is designed to corrupt immutable shares of v1 or v2 in specific ways."
if debug:
log.msg("original data: %r" % (data, ))
return data[:0x0c + 0x221] + byteschr(
ord(data[0x0c + 0x221:0x0c + 0x221 + 1]) ^ 0x02) + data[0x0c + 0x2210 +
1:]
def test_odd_sizes(self):
for j in range(2**6):
lib = random.randrange(1, 2**8)
numos = mathutil.div_ceil(lib, 8)
bs = insecurerandstr(numos)
# zero-out unused least-sig bits
if lib % 8:
b = ord(bs[-1:])
b = b >> (8 - (lib % 8))
b = b << (8 - (lib % 8))
bs = bs[:-1] + byteschr(b)
asl = base62.b2a_l(bs, lib)
assert len(
asl) == base62.num_chars_that_this_many_octets_encode_to(
numos
) # the size of the base-62 encoding must be just right
bs2l = base62.a2b_l(asl, lib)
assert len(
bs2l) == numos # the size of the result must be just right
assert bs == bs2l
def _corrupt_share_data_last_byte(data, debug=False):
"""Scramble the file data -- flip all bits of the last byte."""
sharevernum = struct.unpack(">L", data[0x0c:0x0c + 4])[0]
assert sharevernum in (
1, 2
), "This test is designed to corrupt immutable shares of v1 or v2 in specific ways, not v%d." % sharevernum
if sharevernum == 1:
sharedatasize = struct.unpack(">L",
data[0x0c + 0x08:0x0c + 0x08 + 4])[0]
offset = 0x0c + 0x24 + sharedatasize - 1
else:
sharedatasize = struct.unpack(">Q",
data[0x0c + 0x08:0x0c + 0x0c + 8])[0]
offset = 0x0c + 0x44 + sharedatasize - 1
newdata = data[:offset] + byteschr(ord(data[offset:offset + 1])
^ 0xFF) + data[offset + 1:]
if debug:
log.msg(
"testing: flipping all bits of byte at offset %d: %r, newdata: %r"
% (offset, data[offset], newdata[offset]))
return newdata
import string
maketrans = string.maketrans
translate = string.translate
else:
maketrans = bytes.maketrans
translate = bytes.translate
from past.builtins import chr as byteschr
from allmydata.util.mathutil import log_ceil, log_floor
chars = b"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
BASE62CHAR = b'[' + chars + b']'
vals = b''.join([byteschr(i) for i in range(62)])
c2vtranstable = maketrans(chars, vals)
v2ctranstable = maketrans(vals, chars)
identitytranstable = maketrans(chars, chars)
def b2a(os):
"""
@param os the data to be encoded (as bytes)
@return the contents of os in base-62 encoded form, as bytes
"""
cs = b2a_l(os, len(os) * 8)
assert num_octets_that_encode_to_this_many_chars(
len(cs)) == len(os), "%s != %s, numchars: %s" % (
num_octets_that_encode_to_this_many_chars(
def _xor(a, b):
return b"".join([byteschr(c ^ b) for c in a])
def flip_bit(good): # flips the last bit
return good[:-1] + byteschr(ord(good[-1]) ^ 0x01)
def _xor(a, b):
return b"".join([byteschr(c ^ b) for c in future_bytes(a)])