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On load, use cadence for counter increase
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Change data cipher default to xchacha20

Issue linuxboot#7
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@tasket
tasket committed Aug 26, 2021
1 parent 74ea044 commit 74c915f
Showing 1 changed file with 44 additions and 41 deletions.
85 changes: 44 additions & 41 deletions wyng
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Original file line number Diff line number Diff line change
Expand Up @@ -85,12 +85,12 @@ class ArchiveSet:
return

# init metadata crypto
if True: #### self.salt_f:
if not mcrypto and not passphrase: passphrase = ask_passphrase()
if not mcrypto:
self.mcrypto = mcrypto = DataCryptography("aes-256-siv", self.confpath+".salt",
slot=1, passphrase=passphrase[:])
###elif check options.crypto and/or passphrase, throw exception
if not mcrypto and not passphrase: passphrase = ask_passphrase()
if not mcrypto:
assert passphrase and passphrase != bytes(len(passphrase))
self.mcrypto = mcrypto \
= DataCryptography("aes-256-siv", self.confpath+".salt",
slot=1, passphrase=passphrase[:])

# decode archive.ini file
with open(self.confpath, "rb") as f: buf = f.read(self.max_conf_sz)
Expand All @@ -111,9 +111,9 @@ class ArchiveSet:
# init data crypto
if mcrypto and not self.datacrypto:
assert passphrase and passphrase != bytes(len(passphrase))
self.datacrypto= datacrypto = DataCryptography(self.data_cipher, mcrypto.keyfile,
slot=0, passphrase=passphrase)
self.datacrypto.ctcadence = 20
self.datacrypto = datacrypto \
= DataCryptography(self.data_cipher, mcrypto.keyfile, slot=0,
passphrase=passphrase, cadence=20)

if mcrypto:
# use higest known counter values
Expand All @@ -126,7 +126,7 @@ class ArchiveSet:

# load volume metadata objects
for key, value in cp["volumes"].items():
vid, hashval = value.split(" ", maxsplit=1) ; assert vid.startswith("Vol_")
vid, hashval = value.split(" ", maxsplit=1)
# conditions when a volume must be loaded:
# - allvols flag is set
# - in_process flag from an unfinished action
Expand All @@ -146,6 +146,7 @@ class ArchiveSet:

def save_conf(self, ext=""):
c = self.conf['var'] ; mcrypto = self.mcrypto
c['uuid'] = self.uuid if self.uuid else str(uuid.uuid4())
c['updated_at'] = self.updated_at = str(time.time())
c['format_ver'] = str(format_version)
c['chunksize'] = str(self.chunksize)
Expand All @@ -157,10 +158,11 @@ class ArchiveSet:
c['destsys'] = self.destsys # move
c['destdir'] = self.destdir
c['destmountpoint'] = self.destmountpoint
c['uuid'] = self.uuid if self.uuid else str(uuid.uuid4())
c['data_cipher'] = self.data_cipher
if self.mcrypto:
self.mci_count = mcrypto.counter ; self.dataci_count = self.datacrypto.counter
c['data_cipher'] = self.data_cipher
if self.datacrypto.counter > self.datacrypto.ctstart:
self.dataci_count = self.datacrypto.counter
self.mci_count = mcrypto.counter
c['dataci_count']= str(self.dataci_count)
c['mci_count'] = str(self.mci_count)
self.conf['in_process'] = { x: ln if type(ln) is str else ":|".join(ln)
Expand Down Expand Up @@ -542,17 +544,17 @@ class DataCryptography():
crypto_ciphers = {"aes-256-siv", "aes-256-cbc", "xchacha20"}


def __init__(self, ci_type, keyfile, slot, passphrase, init=False):
def __init__(self, ci_type, keyfile, slot, passphrase, cadence=1, init=False):
assert passphrase is None or type(passphrase) == bytearray
assert ci_type in self.crypto_ciphers
assert cadence > 0 and ci_type in self.crypto_ciphers
if not issubclass(type(keyfile), io.IOBase):
if not exists(keyfile): open(keyfile, "wb").close()
keyfile = open(keyfile, "r+b")

self.keyfile = keyfile ; self.ci_type = ci_type
self.key = None ; kbits = self.crypto_key_bits
self.slot = slot ; self.counter = None ; self.ctcadence = 1
self.get_rnd = get_random_bytes
self.slot = slot ; self.counter = self.ctstart = None
self.ctcadence = cadence ; self.get_rnd = get_random_bytes

if ci_type == "aes-256-cbc":
# FIX: Probably requires IV encryption with different non-data key
Expand Down Expand Up @@ -591,20 +593,19 @@ class DataCryptography():
if init:
self.key = self.new_key(passphrase)
else:
keyfile.seek(self.slot_offset)
self.counter = int.from_bytes(keyfile.read(self.countsz), byteorder="big") + 1
keyfile.seek(self.slot_offset) ; ctbytes = keyfile.read(self.countsz)
self.counter = self.ctstart = cadence - 1 + int.from_bytes(ctbytes, "big")
salt = keyfile.read(self.key_sz) ; assert len(salt) == self.key_sz
self.key = self.derive_key(salt, passphrase)


def __del__(self):
self.save_counter()
if self.counter and self.counter > self.ctstart: self.save_counter()
if self.key: clear_array(self.key)


# Key file binary format: counter=8B, key=key_sz
def new_key(self, passphrase):
salt = self.get_rnd(self.key_sz) ; self.counter = 0
salt = self.get_rnd(self.key_sz) ; self.counter = self.ctstart = 0
self.keyfile.seek(self.slot_offset) ; self.keyfile.write(bytes(self.countsz) + salt)
return self.derive_key(salt, passphrase)

Expand All @@ -622,16 +623,15 @@ class DataCryptography():
# A random 'bolster' block is added as a prefix to the plaintext buffer;
# A random padding is also used and 'buf' must be prefixed by len % blk_sz (1 byte)
def _enc_aes_256_cbc_rndpad(self, buf):
iv = self.get_rnd(self.rndivsz) + self.counter.to_bytes(self.countsz, "big")
blk_sz = self.blk_sz
cipher = self.AES_new(self.key, self.mode, iv=iv)
pad_sz = blk_sz - (len(buf) % blk_sz) & self.ps_mask
blk_sz = self.blk_sz ; pad_sz = blk_sz - (len(buf) % blk_sz) & self.ps_mask
if pad_sz: buf += self.get_rnd(pad_sz)

plaintxt= self.get_rnd(blk_sz) + buf
buf = cipher.encrypt(plaintxt) + pad_sz.to_bytes(1,"big")
self.save_counter() ; self.counter += len(plaintxt) // blk_sz
plaintxt= self.get_rnd(blk_sz) + buf ; self.counter += len(plaintxt) // blk_sz
if self.counter > self.max_count: raise ValueError("Key exhaustion.")
iv = self.get_rnd(self.rndivsz) + self.counter.to_bytes(self.countsz, "big")
cipher = self.AES_new(self.key, self.mode, iv=iv)
buf = cipher.encrypt(plaintxt) + pad_sz.to_bytes(1,"big")
self.save_counter()
return iv + buf

# Decrypt aes-256-cbc:
Expand All @@ -646,12 +646,12 @@ class DataCryptography():

# Encrypt aes-256-siv:
def _enc_aes_256_siv(self, buf):
self.counter += 1
if self.counter > self.max_count: raise ValueError("Key exhaustion.")
nonce = self.get_rnd(self.randomsz) + self.counter.to_bytes(self.countsz, "big")
cipher = self.AES_new(self.key, self.mode, nonce=nonce)
buf, ci_tag = cipher.encrypt_and_digest(buf)
if self.counter % self.ctcadence == 0: self.save_counter()
self.counter += 1
if self.counter > self.max_count: raise ValueError("Key exhaustion.")
return nonce + ci_tag + buf

# Decrypt aes-256-siv:
Expand All @@ -663,12 +663,12 @@ class DataCryptography():

# Encrypt [X]ChaCha20:
def _enc_chacha20(self, buf):
self.counter += 1
if self.counter > self.max_count: raise ValueError("Key exhaustion.")
nonce = self.get_rnd(self.randomsz) + self.counter.to_bytes(self.countsz, "big")
cipher = self.ChaCha20_new(key=self.key, nonce=nonce)
buf = cipher.encrypt(buf)
if self.counter % self.ctcadence == 0: self.save_counter()
self.counter += 1
if self.counter > self.max_count: raise ValueError("Key exhaustion.")
return nonce + buf

# Decrypt [X]ChaCha20:
Expand Down Expand Up @@ -898,16 +898,16 @@ def arch_init(aset):
passphrase=passphrase, init=True)

elif aset.data_cipher != "off":
raise ValueError("Unknown cipher.")
raise ValueError("Invalid cipher option.")

print(); print("Encryption =", aset.data_cipher)
print(); print("Encryption :", aset.data_cipher)

if options.hashtype:
if options.hashtype not in hash_funcs:
x_it(1, "Hash function '"+options.hashtype+"' is not available on this system.")
aset.hashtype = options.hashtype

print("Hashing =", aset.hashtype)
print("Hashing :", aset.hashtype)

if options.compression:
if ":" in options.compression:
Expand All @@ -920,7 +920,7 @@ def arch_init(aset):
x_it(1, "Invalid compression spec.")
aset.compression = compression ; aset.compr_level = compr_level

print("Compression = %s:%s" % (aset.compression, aset.compr_level))
print("Compression : %s:%s" % (aset.compression, aset.compr_level))

if options.chfactor:
# accepts an exponent from 1 to 6
Expand Down Expand Up @@ -1136,7 +1136,7 @@ def get_configs_remote():
assert isinstance(mcrypto, DataCryptography) and isinstance(datacrypto, DataCryptography)

# Initial auth successful! Fetch + auth volume metadata...
mcrypto = new_aset.mcrypto ; datacrypto = new_aset.datacrypto
#mcrypto = new_aset.mcrypto ; datacrypto = new_aset.datacrypto
recv_list= [(x.split()[0]+"/volinfo", ArchiveSet.max_volinfosz)
for x in new_aset.conf["volumes"].values()]
fetch_file_blobs(recv_list)
Expand Down Expand Up @@ -3132,7 +3132,7 @@ def cleanup():

# Constants / Globals
prog_name = "wyng"
prog_version = "0.4.0wip" ; prog_date = "20210823"
prog_version = "0.4.0wip" ; prog_date = "20210824"
format_version = 3 ; debug = False ; tmpdir = None

# Disk block size:
Expand Down Expand Up @@ -3204,7 +3204,7 @@ parser.add_argument("--remap", action="store_true", default=False, help="Remap s
parser.add_argument("--local", default="", help="Init: LVM vg/pool containing source volumes")
parser.add_argument("--dest", default="", help="Init: type:location of archive")
parser.add_argument("--subdir", default="", help="Init: optional subdir for --dest")
parser.add_argument("--encrypt", default="aes-256-siv", help="Init: compression type:level")
parser.add_argument("--encrypt", default="xchacha20", help="Init: compression type:level")
parser.add_argument("--compression", default="", help="Init: compression type:level")
parser.add_argument("--hashtype", default="", help="Init: hash function type")
parser.add_argument("--chunk-factor", dest="chfactor", type=int,
Expand Down Expand Up @@ -3298,7 +3298,10 @@ if not dest_online and (options.remap or options.from_arch \
if options.from_arch:
aset = get_configs_remote()

print("Archive last updated:", aset.updated_at)
# Display archive update time as local time
arch_dt_raw = datetime.datetime.fromtimestamp(float(aset.updated_at), datetime.timezone.utc)
arch_dt = arch_dt_raw.astimezone().isoformat(sep=u" ")
sys.stderr.write("Archive last updated %s (%s)\n" % (arch_dt[:-6], arch_dt[-6:]))

# Set 'l_vols' to reference selected volgroup and check for orphan snapshots
if aset.vgname in volgroups: l_vols = volgroups[aset.vgname].lvs
Expand Down

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