def _got_key( (pubkey, privkey) ):
nm.key_generator = SameKeyGenerator(pubkey, privkey)
pubkey_s = pubkey.serialize()
privkey_s = privkey.serialize()
u = uri.WriteableSSKFileURI(ssk_writekey_hash(privkey_s),
ssk_pubkey_fingerprint_hash(pubkey_s))
self._storage_index = u.get_storage_index()
def _got_results_one_share(self, shnum, data, peerid, lp):
self.log(format="_got_results: got shnum #%(shnum)d from peerid %(peerid)s",
shnum=shnum,
peerid=idlib.shortnodeid_b2a(peerid),
level=log.NOISY,
parent=lp)
# this might raise NeedMoreDataError, if the pubkey and signature
# live at some weird offset. That shouldn't happen, so I'm going to
# treat it as a bad share.
(seqnum, root_hash, IV, k, N, segsize, datalength,
pubkey_s, signature, prefix) = unpack_prefix_and_signature(data)
if not self._node.get_pubkey():
fingerprint = hashutil.ssk_pubkey_fingerprint_hash(pubkey_s)
assert len(fingerprint) == 32
if fingerprint != self._node.get_fingerprint():
raise CorruptShareError(peerid, shnum,
"pubkey doesn't match fingerprint")
self._node._populate_pubkey(self._deserialize_pubkey(pubkey_s))
if self._need_privkey:
self._try_to_extract_privkey(data, peerid, shnum, lp)
(ig_version, ig_seqnum, ig_root_hash, ig_IV, ig_k, ig_N,
ig_segsize, ig_datalen, offsets) = unpack_header(data)
offsets_tuple = tuple( [(key,value) for key,value in offsets.items()] )
verinfo = (seqnum, root_hash, IV, segsize, datalength, k, N, prefix,
offsets_tuple)
if verinfo not in self._valid_versions:
# it's a new pair. Verify the signature.
valid = self._node.get_pubkey().verify(prefix, signature)
if not valid:
raise CorruptShareError(peerid, shnum, "signature is invalid")
# ok, it's a valid verinfo. Add it to the list of validated
# versions.
self.log(" found valid version %d-%s from %s-sh%d: %d-%d/%d/%d"
% (seqnum, base32.b2a(root_hash)[:4],
idlib.shortnodeid_b2a(peerid), shnum,
k, N, segsize, datalength),
parent=lp)
self._valid_versions.add(verinfo)
# We now know that this is a valid candidate verinfo.
if (peerid, shnum) in self._servermap.bad_shares:
# we've been told that the rest of the data in this share is
# unusable, so don't add it to the servermap.
self.log("but we've been told this is a bad share",
parent=lp, level=log.UNUSUAL)
return verinfo
# Add the info to our servermap.
timestamp = time.time()
self._servermap.add_new_share(peerid, shnum, verinfo, timestamp)
# and the versionmap
self.versionmap.add(verinfo, (shnum, peerid, timestamp))
return verinfo
def create_with_keys(self, keypair, contents,
version=SDMF_VERSION):
"""Call this to create a brand-new mutable file. It will create the
shares, find homes for them, and upload the initial contents (created
with the same rules as IClient.create_mutable_file() ). Returns a
Deferred that fires (with the MutableFileNode instance you should
use) when it completes.
"""
(pubkey, privkey) = keypair
self._pubkey, self._privkey = pubkey, privkey
pubkey_s = self._pubkey.serialize()
privkey_s = self._privkey.serialize()
self._writekey = hashutil.ssk_writekey_hash(privkey_s)
self._encprivkey = self._encrypt_privkey(self._writekey, privkey_s)
self._fingerprint = hashutil.ssk_pubkey_fingerprint_hash(pubkey_s)
if version == MDMF_VERSION:
self._uri = WriteableMDMFFileURI(self._writekey, self._fingerprint)
self._protocol_version = version
elif version == SDMF_VERSION:
self._uri = WriteableSSKFileURI(self._writekey, self._fingerprint)
self._protocol_version = version
self._readkey = self._uri.readkey
self._storage_index = self._uri.storage_index
initial_contents = self._get_initial_contents(contents)
return self._upload(initial_contents, None)
def dump_MDMF_share(m, length, options):
from allmydata.mutable.layout import MDMFSlotReadProxy
from allmydata.util import base32, hashutil
from allmydata.uri import MDMFVerifierURI
from allmydata.util.encodingutil import quote_output, to_bytes
offset = m.DATA_OFFSET
out = options.stdout
f = open(options['filename'], "rb")
storage_index = None
shnum = 0
class ShareDumper(MDMFSlotReadProxy):
def _read(self, readvs, force_remote=False, queue=False):
data = []
for (where, length) in readvs:
f.seek(offset + where)
data.append(f.read(length))
return defer.succeed({shnum: data})
p = ShareDumper(None, storage_index, shnum)
def extract(func):
stash = []
# these methods return Deferreds, but we happen to know that they run
# synchronously when not actually talking to a remote server
d = func()
d.addCallback(stash.append)
return stash[0]
verinfo = extract(p.get_verinfo)
encprivkey = extract(p.get_encprivkey)
signature = extract(p.get_signature)
pubkey = extract(p.get_verification_key)
block_hash_tree = extract(p.get_blockhashes)
share_hash_chain = extract(p.get_sharehashes)
f.close()
(seqnum, root_hash, salt_to_use, segsize, datalen, k, N, prefix,
offsets) = verinfo
print(" MDMF contents:", file=out)
print(" seqnum: %d" % seqnum, file=out)
print(" root_hash: %s" % unicode(base32.b2a(root_hash), "utf-8"),
file=out)
#print(" IV: %s" % base32.b2a(IV), file=out)
print(" required_shares: %d" % k, file=out)
print(" total_shares: %d" % N, file=out)
print(" segsize: %d" % segsize, file=out)
print(" datalen: %d" % datalen, file=out)
print(" enc_privkey: %d bytes" % len(encprivkey), file=out)
print(" pubkey: %d bytes" % len(pubkey), file=out)
print(" signature: %d bytes" % len(signature), file=out)
share_hash_ids = ",".join(
[str(hid) for hid in sorted(share_hash_chain.keys())])
print(" share_hash_chain: %s" % share_hash_ids, file=out)
print(" block_hash_tree: %d nodes" % len(block_hash_tree), file=out)
# the storage index isn't stored in the share itself, so we depend upon
# knowing the parent directory name to get it
pieces = options['filename'].split(os.sep)
if len(pieces) >= 2:
piece = to_bytes(pieces[-2])
if base32.could_be_base32_encoded(piece):
storage_index = base32.a2b(piece)
fingerprint = hashutil.ssk_pubkey_fingerprint_hash(pubkey)
u = MDMFVerifierURI(storage_index, fingerprint)
verify_cap = u.to_string()
print(" verify-cap:",
quote_output(verify_cap, quotemarks=False),
file=out)
if options['offsets']:
# NOTE: this offset-calculation code is fragile, and needs to be
# merged with MutableShareFile's internals.
print(file=out)
print(" Section Offsets:", file=out)
def printoffset(name, value, shift=0):
print("%s%.20s: %s (0x%x)" % (" " * shift, name, value, value),
file=out)
printoffset("first lease", m.HEADER_SIZE, 2)
printoffset("share data", m.DATA_OFFSET, 2)
o_seqnum = m.DATA_OFFSET + struct.calcsize(">B")
printoffset("seqnum", o_seqnum, 4)
o_root_hash = m.DATA_OFFSET + struct.calcsize(">BQ")
printoffset("root_hash", o_root_hash, 4)
for k in [
"enc_privkey", "share_hash_chain", "signature",
"verification_key", "verification_key_end", "share_data",
"block_hash_tree", "EOF"
]:
name = {
"share_data": "block data",
"verification_key": "pubkey",
"verification_key_end": "end of pubkey",
"EOF": "end of share data"
}.get(k, k)
offset = m.DATA_OFFSET + offsets[k]
printoffset(name, offset, 4)
f = open(options['filename'], "rb")
printoffset("extra leases", m._read_extra_lease_offset(f) + 4, 2)
f.close()
print(file=out)
def dump_SDMF_share(m, length, options):
from allmydata.mutable.layout import unpack_share, unpack_header
from allmydata.mutable.common import NeedMoreDataError
from allmydata.util import base32, hashutil
from allmydata.uri import SSKVerifierURI
from allmydata.util.encodingutil import quote_output, to_bytes
offset = m.DATA_OFFSET
out = options.stdout
f = open(options['filename'], "rb")
f.seek(offset)
data = f.read(min(length, 2000))
f.close()
try:
pieces = unpack_share(data)
except NeedMoreDataError as e:
# retry once with the larger size
size = e.needed_bytes
f = open(options['filename'], "rb")
f.seek(offset)
data = f.read(min(length, size))
f.close()
pieces = unpack_share(data)
(seqnum, root_hash, IV, k, N, segsize, datalen, pubkey, signature,
share_hash_chain, block_hash_tree, share_data, enc_privkey) = pieces
(ig_version, ig_seqnum, ig_roothash, ig_IV, ig_k, ig_N, ig_segsize,
ig_datalen, offsets) = unpack_header(data)
print(" SDMF contents:", file=out)
print(" seqnum: %d" % seqnum, file=out)
print(" root_hash: %s" % unicode(base32.b2a(root_hash), "utf-8"),
file=out)
print(" IV: %s" % unicode(base32.b2a(IV), "utf-8"), file=out)
print(" required_shares: %d" % k, file=out)
print(" total_shares: %d" % N, file=out)
print(" segsize: %d" % segsize, file=out)
print(" datalen: %d" % datalen, file=out)
print(" enc_privkey: %d bytes" % len(enc_privkey), file=out)
print(" pubkey: %d bytes" % len(pubkey), file=out)
print(" signature: %d bytes" % len(signature), file=out)
share_hash_ids = ",".join(
sorted([str(hid) for hid in share_hash_chain.keys()]))
print(" share_hash_chain: %s" % share_hash_ids, file=out)
print(" block_hash_tree: %d nodes" % len(block_hash_tree), file=out)
# the storage index isn't stored in the share itself, so we depend upon
# knowing the parent directory name to get it
pieces = options['filename'].split(os.sep)
if len(pieces) >= 2:
piece = to_bytes(pieces[-2])
if base32.could_be_base32_encoded(piece):
storage_index = base32.a2b(piece)
fingerprint = hashutil.ssk_pubkey_fingerprint_hash(pubkey)
u = SSKVerifierURI(storage_index, fingerprint)
verify_cap = u.to_string()
print(" verify-cap:",
quote_output(verify_cap, quotemarks=False),
file=out)
if options['offsets']:
# NOTE: this offset-calculation code is fragile, and needs to be
# merged with MutableShareFile's internals.
print(file=out)
print(" Section Offsets:", file=out)
def printoffset(name, value, shift=0):
print("%s%20s: %s (0x%x)" % (" " * shift, name, value, value),
file=out)
printoffset("first lease", m.HEADER_SIZE)
printoffset("share data", m.DATA_OFFSET)
o_seqnum = m.DATA_OFFSET + struct.calcsize(">B")
printoffset("seqnum", o_seqnum, 2)
o_root_hash = m.DATA_OFFSET + struct.calcsize(">BQ")
printoffset("root_hash", o_root_hash, 2)
for k in [
"signature", "share_hash_chain", "block_hash_tree",
"share_data", "enc_privkey", "EOF"
]:
name = {
"share_data": "block data",
"EOF": "end of share data"
}.get(k, k)
offset = m.DATA_OFFSET + offsets[k]
printoffset(name, offset, 2)
f = open(options['filename'], "rb")
printoffset("extra leases", m._read_extra_lease_offset(f) + 4)
f.close()
print(file=out)
print >>out, " enc_privkey: %d bytes" % len(enc_privkey)
print >>out, " pubkey: %d bytes" % len(pubkey)
print >>out, " signature: %d bytes" % len(signature)
share_hash_ids = ",".join(sorted([str(hid)
for hid in share_hash_chain.keys()]))
print >>out, " share_hash_chain: %s" % share_hash_ids
print >>out, " block_hash_tree: %d nodes" % len(block_hash_tree)
# the storage index isn't stored in the share itself, so we depend upon
# knowing the parent directory name to get it
pieces = options['filename'].split(os.sep)
if len(pieces) >= 2:
piece = to_str(pieces[-2])
if base32.could_be_base32_encoded(piece):
storage_index = base32.a2b(piece)
fingerprint = hashutil.ssk_pubkey_fingerprint_hash(pubkey)
u = SSKVerifierURI(storage_index, fingerprint)
verify_cap = u.to_string()
print >>out, " verify-cap:", quote_output(verify_cap, quotemarks=False)
if options['offsets']:
# NOTE: this offset-calculation code is fragile, and needs to be
# merged with MutableShareFile's internals.
print >>out
print >>out, " Section Offsets:"
def printoffset(name, value, shift=0):
print >>out, "%s%20s: %s (0x%x)" % (" "*shift, name, value, value)
printoffset("first lease", m.HEADER_SIZE)
printoffset("share data", m.DATA_OFFSET)
o_seqnum = m.DATA_OFFSET + struct.calcsize(">B")
printoffset("seqnum", o_seqnum, 2)
def dump_MDMF_share(m, length, options):
from allmydata.mutable.layout import MDMFSlotReadProxy
from allmydata.util import base32, hashutil
from allmydata.uri import MDMFVerifierURI
from allmydata.util.encodingutil import quote_output, to_str
offset = m.DATA_OFFSET
out = options.stdout
f = open(options['filename'], "rb")
storage_index = None; shnum = 0
class ShareDumper(MDMFSlotReadProxy):
def _read(self, readvs, force_remote=False, queue=False):
data = []
for (where,length) in readvs:
f.seek(offset+where)
data.append(f.read(length))
return defer.succeed({shnum: data})
p = ShareDumper(None, storage_index, shnum)
def extract(func):
stash = []
# these methods return Deferreds, but we happen to know that they run
# synchronously when not actually talking to a remote server
d = func()
d.addCallback(stash.append)
return stash[0]
verinfo = extract(p.get_verinfo)
encprivkey = extract(p.get_encprivkey)
signature = extract(p.get_signature)
pubkey = extract(p.get_verification_key)
block_hash_tree = extract(p.get_blockhashes)
share_hash_chain = extract(p.get_sharehashes)
f.close()
(seqnum, root_hash, salt_to_use, segsize, datalen, k, N, prefix,
offsets) = verinfo
print >>out, " MDMF contents:"
print >>out, " seqnum: %d" % seqnum
print >>out, " root_hash: %s" % base32.b2a(root_hash)
#print >>out, " IV: %s" % base32.b2a(IV)
print >>out, " required_shares: %d" % k
print >>out, " total_shares: %d" % N
print >>out, " segsize: %d" % segsize
print >>out, " datalen: %d" % datalen
print >>out, " enc_privkey: %d bytes" % len(encprivkey)
print >>out, " pubkey: %d bytes" % len(pubkey)
print >>out, " signature: %d bytes" % len(signature)
share_hash_ids = ",".join([str(hid)
for hid in sorted(share_hash_chain.keys())])
print >>out, " share_hash_chain: %s" % share_hash_ids
print >>out, " block_hash_tree: %d nodes" % len(block_hash_tree)
# the storage index isn't stored in the share itself, so we depend upon
# knowing the parent directory name to get it
pieces = options['filename'].split(os.sep)
if len(pieces) >= 2:
piece = to_str(pieces[-2])
if base32.could_be_base32_encoded(piece):
storage_index = base32.a2b(piece)
fingerprint = hashutil.ssk_pubkey_fingerprint_hash(pubkey)
u = MDMFVerifierURI(storage_index, fingerprint)
verify_cap = u.to_string()
print >>out, " verify-cap:", quote_output(verify_cap, quotemarks=False)
if options['offsets']:
# NOTE: this offset-calculation code is fragile, and needs to be
# merged with MutableShareFile's internals.
print >>out
print >>out, " Section Offsets:"
def printoffset(name, value, shift=0):
print >>out, "%s%.20s: %s (0x%x)" % (" "*shift, name, value, value)
printoffset("first lease", m.HEADER_SIZE, 2)
printoffset("share data", m.DATA_OFFSET, 2)
o_seqnum = m.DATA_OFFSET + struct.calcsize(">B")
printoffset("seqnum", o_seqnum, 4)
o_root_hash = m.DATA_OFFSET + struct.calcsize(">BQ")
printoffset("root_hash", o_root_hash, 4)
for k in ["enc_privkey", "share_hash_chain", "signature",
"verification_key", "verification_key_end",
"share_data", "block_hash_tree", "EOF"]:
name = {"share_data": "block data",
"verification_key": "pubkey",
"verification_key_end": "end of pubkey",
"EOF": "end of share data"}.get(k,k)
offset = m.DATA_OFFSET + offsets[k]
printoffset(name, offset, 4)
f = open(options['filename'], "rb")
printoffset("extra leases", m._read_extra_lease_offset(f) + 4, 2)
f.close()
print >>out
print >>out, " enc_privkey: %d bytes" % len(enc_privkey)
print >>out, " pubkey: %d bytes" % len(pubkey)
print >>out, " signature: %d bytes" % len(signature)
share_hash_ids = ",".join(sorted([str(hid)
for hid in share_hash_chain.keys()]))
print >>out, " share_hash_chain: %s" % share_hash_ids
print >>out, " block_hash_tree: %d nodes" % len(block_hash_tree)
# the storage index isn't stored in the share itself, so we depend upon
# knowing the parent directory name to get it
pieces = options['filename'].split(os.sep)
if len(pieces) >= 2:
piece = to_str(pieces[-2])
if base32.could_be_base32_encoded(piece):
storage_index = base32.a2b(piece)
fingerprint = hashutil.ssk_pubkey_fingerprint_hash(pubkey)
u = SSKVerifierURI(storage_index, fingerprint)
verify_cap = u.to_string()
print >>out, " verify-cap:", quote_output(verify_cap, quotemarks=False)
if options['offsets']:
# NOTE: this offset-calculation code is fragile, and needs to be
# merged with MutableShareFile's internals.
print >>out
print >>out, " Section Offsets:"
def printoffset(name, value, shift=0):
print >>out, "%s%20s: %s (0x%x)" % (" "*shift, name, value, value)
printoffset("first lease", m.HEADER_SIZE)
printoffset("share data", m.DATA_OFFSET)
o_seqnum = m.DATA_OFFSET + struct.calcsize(">B")
printoffset("seqnum", o_seqnum, 2)
class MutableFileNode:
implements(IMutableFileNode, ICheckable)
def __init__(self, storage_broker, secret_holder,
default_encoding_parameters, history):
self._storage_broker = storage_broker
self._secret_holder = secret_holder
self._default_encoding_parameters = default_encoding_parameters
self._history = history
self._pubkey = None # filled in upon first read
self._privkey = None # filled in if we're mutable
# we keep track of the last encoding parameters that we use. These
# are updated upon retrieve, and used by publish. If we publish
# without ever reading (i.e. overwrite()), then we use these values.
self._required_shares = default_encoding_parameters["k"]
self._total_shares = default_encoding_parameters["n"]
self._sharemap = {} # known shares, shnum-to-[nodeids]
self._cache = ResponseCache()
self._most_recent_size = None
# all users of this MutableFileNode go through the serializer. This
# takes advantage of the fact that Deferreds discard the callbacks
# that they're done with, so we can keep using the same Deferred
# forever without consuming more and more memory.
self._serializer = defer.succeed(None)
def __repr__(self):
if hasattr(self, '_uri'):
return "<%s %x %s %s>" % (self.__class__.__name__, id(self),
self.is_readonly() and 'RO'
or 'RW', self._uri.abbrev())
else:
return "<%s %x %s %s>" % (self.__class__.__name__, id(self), None,
None)
def init_from_cap(self, filecap):
# we have the URI, but we have not yet retrieved the public
# verification key, nor things like 'k' or 'N'. If and when someone
# wants to get our contents, we'll pull from shares and fill those
# in.
assert isinstance(filecap, (ReadonlySSKFileURI, WriteableSSKFileURI))
self._uri = filecap
self._writekey = None
if isinstance(filecap, WriteableSSKFileURI):
self._writekey = self._uri.writekey
self._readkey = self._uri.readkey
self._storage_index = self._uri.storage_index
self._fingerprint = self._uri.fingerprint
# the following values are learned during Retrieval
# self._pubkey
# self._required_shares
# self._total_shares
# and these are needed for Publish. They are filled in by Retrieval
# if possible, otherwise by the first peer that Publish talks to.
self._privkey = None
self._encprivkey = None
return self
def create_with_keys(self, (pubkey, privkey), contents):
"""Call this to create a brand-new mutable file. It will create the
shares, find homes for them, and upload the initial contents (created
with the same rules as IClient.create_mutable_file() ). Returns a
Deferred that fires (with the MutableFileNode instance you should
use) when it completes.
"""
self._pubkey, self._privkey = pubkey, privkey
pubkey_s = self._pubkey.serialize()
privkey_s = self._privkey.serialize()
self._writekey = hashutil.ssk_writekey_hash(privkey_s)
self._encprivkey = self._encrypt_privkey(self._writekey, privkey_s)
self._fingerprint = hashutil.ssk_pubkey_fingerprint_hash(pubkey_s)
self._uri = WriteableSSKFileURI(self._writekey, self._fingerprint)
self._readkey = self._uri.readkey
self._storage_index = self._uri.storage_index
initial_contents = self._get_initial_contents(contents)
return self._upload(initial_contents, None)
def dump_SDMF_share(m, length, options):
from allmydata.mutable.layout import unpack_share, unpack_header
from allmydata.mutable.common import NeedMoreDataError
from allmydata.util import base32, hashutil
from allmydata.uri import SSKVerifierURI
from allmydata.util.encodingutil import quote_output, to_str
offset = m.DATA_OFFSET
out = options.stdout
f = open(options['filename'], "rb")
f.seek(offset)
data = f.read(min(length, 2000))
f.close()
try:
pieces = unpack_share(data)
except NeedMoreDataError as e:
# retry once with the larger size
size = e.needed_bytes
f = open(options['filename'], "rb")
f.seek(offset)
data = f.read(min(length, size))
f.close()
pieces = unpack_share(data)
(seqnum, root_hash, IV, k, N, segsize, datalen,
pubkey, signature, share_hash_chain, block_hash_tree,
share_data, enc_privkey) = pieces
(ig_version, ig_seqnum, ig_roothash, ig_IV, ig_k, ig_N, ig_segsize,
ig_datalen, offsets) = unpack_header(data)
print(" SDMF contents:", file=out)
print(" seqnum: %d" % seqnum, file=out)
print(" root_hash: %s" % base32.b2a(root_hash), file=out)
print(" IV: %s" % base32.b2a(IV), file=out)
print(" required_shares: %d" % k, file=out)
print(" total_shares: %d" % N, file=out)
print(" segsize: %d" % segsize, file=out)
print(" datalen: %d" % datalen, file=out)
print(" enc_privkey: %d bytes" % len(enc_privkey), file=out)
print(" pubkey: %d bytes" % len(pubkey), file=out)
print(" signature: %d bytes" % len(signature), file=out)
share_hash_ids = ",".join(sorted([str(hid)
for hid in share_hash_chain.keys()]))
print(" share_hash_chain: %s" % share_hash_ids, file=out)
print(" block_hash_tree: %d nodes" % len(block_hash_tree), file=out)
# the storage index isn't stored in the share itself, so we depend upon
# knowing the parent directory name to get it
pieces = options['filename'].split(os.sep)
if len(pieces) >= 2:
piece = to_str(pieces[-2])
if base32.could_be_base32_encoded(piece):
storage_index = base32.a2b(piece)
fingerprint = hashutil.ssk_pubkey_fingerprint_hash(pubkey)
u = SSKVerifierURI(storage_index, fingerprint)
verify_cap = u.to_string()
print(" verify-cap:", quote_output(verify_cap, quotemarks=False), file=out)
if options['offsets']:
# NOTE: this offset-calculation code is fragile, and needs to be
# merged with MutableShareFile's internals.
print(file=out)
print(" Section Offsets:", file=out)
def printoffset(name, value, shift=0):
print("%s%20s: %s (0x%x)" % (" "*shift, name, value, value), file=out)
printoffset("first lease", m.HEADER_SIZE)
printoffset("share data", m.DATA_OFFSET)
o_seqnum = m.DATA_OFFSET + struct.calcsize(">B")
printoffset("seqnum", o_seqnum, 2)
o_root_hash = m.DATA_OFFSET + struct.calcsize(">BQ")
printoffset("root_hash", o_root_hash, 2)
for k in ["signature", "share_hash_chain", "block_hash_tree",
"share_data",
"enc_privkey", "EOF"]:
name = {"share_data": "block data",
"EOF": "end of share data"}.get(k,k)
offset = m.DATA_OFFSET + offsets[k]
printoffset(name, offset, 2)
f = open(options['filename'], "rb")
printoffset("extra leases", m._read_extra_lease_offset(f) + 4)
f.close()
print(file=out)
