def corrupt_share(options):
import random
from allmydata.storage.mutable import MutableShareFile
from allmydata.storage.immutable import ShareFile
from allmydata.mutable.layout import unpack_header
from allmydata.immutable.layout import ReadBucketProxy
out = options.stdout
fn = options['filename']
assert options["offset"] == "block-random", "other offsets not implemented"
# first, what kind of share is it?
def flip_bit(start, end):
offset = random.randrange(start, end)
bit = random.randrange(0, 8)
print("[%d..%d): %d.b%d" % (start, end, offset, bit), file=out)
f = open(fn, "rb+")
f.seek(offset)
d = f.read(1)
d = bchr(ord(d) ^ 0x01)
f.seek(offset)
f.write(d)
f.close()
with open(fn, "rb") as f:
prefix = f.read(32)
if MutableShareFile.is_valid_header(prefix):
# mutable
m = MutableShareFile(fn)
with open(fn, "rb") as f:
f.seek(m.DATA_OFFSET)
# Read enough data to get a mutable header to unpack.
data = f.read(2000)
# make sure this slot contains an SMDF share
assert data[
0:1] == b"\x00", "non-SDMF mutable shares not supported"
f.close()
(version, ig_seqnum, ig_roothash, ig_IV, ig_k, ig_N, ig_segsize,
ig_datalen, offsets) = unpack_header(data)
assert version == 0, "we only handle v0 SDMF files"
start = m.DATA_OFFSET + offsets["share_data"]
end = m.DATA_OFFSET + offsets["enc_privkey"]
flip_bit(start, end)
else:
# otherwise assume it's immutable
f = ShareFile(fn)
bp = ReadBucketProxy(None, None, '')
offsets = bp._parse_offsets(f.read_share_data(0, 0x24))
start = f._data_offset + offsets["data"]
end = f._data_offset + offsets["plaintext_hash_tree"]
flip_bit(start, end)
def corrupt_share(options):
import random
from allmydata.storage.mutable import MutableShareFile
from allmydata.storage.immutable import ShareFile
from allmydata.mutable.layout import unpack_header
from allmydata.immutable.layout import ReadBucketProxy
out = options.stdout
fn = options['filename']
assert options["offset"] == "block-random", "other offsets not implemented"
# first, what kind of share is it?
def flip_bit(start, end):
offset = random.randrange(start, end)
bit = random.randrange(0, 8)
print >>out, "[%d..%d): %d.b%d" % (start, end, offset, bit)
f = open(fn, "rb+")
f.seek(offset)
d = f.read(1)
d = chr(ord(d) ^ 0x01)
f.seek(offset)
f.write(d)
f.close()
f = open(fn, "rb")
prefix = f.read(32)
f.close()
if prefix == MutableShareFile.MAGIC:
# mutable
m = MutableShareFile(fn)
f = open(fn, "rb")
f.seek(m.DATA_OFFSET)
data = f.read(2000)
# make sure this slot contains an SMDF share
assert data[0] == "\x00", "non-SDMF mutable shares not supported"
f.close()
(version, ig_seqnum, ig_roothash, ig_IV, ig_k, ig_N, ig_segsize,
ig_datalen, offsets) = unpack_header(data)
assert version == 0, "we only handle v0 SDMF files"
start = m.DATA_OFFSET + offsets["share_data"]
end = m.DATA_OFFSET + offsets["enc_privkey"]
flip_bit(start, end)
else:
# otherwise assume it's immutable
f = ShareFile(fn)
bp = ReadBucketProxy(None, '', '')
offsets = bp._parse_offsets(f.read_share_data(0, 0x24))
start = f._data_offset + offsets["data"]
end = f._data_offset + offsets["plaintext_hash_tree"]
flip_bit(start, end)
