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storage: use constant-time comparison for write-enablers and lease-secrets

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Brian Warner 2009-03-22 20:21:28 -07:00
parent 01e2032669
commit 5e8c31c3b6
2 changed files with 9 additions and 5 deletions
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5
src/allmydata/storage/immutable.py
View File

@ -6,6 +6,7 @@ from zope.interface import implements
from allmydata.interfaces import RIBucketWriter, RIBucketReader
from allmydata.util import base32, fileutil, log
from allmydata.util.assertutil import precondition
from allmydata.util.hashutil import constant_time_compare
from allmydata.storage.lease import LeaseInfo
from allmydata.storage.common import UnknownImmutableContainerVersionError, \
DataTooLargeError
@ -142,7 +143,7 @@ class ShareFile:
def renew_lease(self, renew_secret, new_expire_time):
for i,lease in enumerate(self.get_leases()):
if lease.renew_secret == renew_secret:
if constant_time_compare(lease.renew_secret, renew_secret):
# yup. See if we need to update the owner time.
if new_expire_time > lease.expiration_time:
# yes
@ -172,7 +173,7 @@ class ShareFile:
leases = list(self.get_leases())
num_leases_removed = 0
for i,lease in enumerate(leases):
if lease.cancel_secret == cancel_secret:
if constant_time_compare(lease.cancel_secret, cancel_secret):
leases[i] = None
num_leases_removed += 1
if not num_leases_removed:

9
src/allmydata/storage/mutable.py
View File

@ -3,6 +3,7 @@ import os, stat, struct
from allmydata.interfaces import BadWriteEnablerError
from allmydata.util import idlib, log
from allmydata.util.assertutil import precondition
from allmydata.util.hashutil import constant_time_compare
from allmydata.storage.lease import LeaseInfo
from allmydata.storage.common import UnknownMutableContainerVersionError, \
DataTooLargeError
@ -266,7 +267,7 @@ class MutableShareFile:
accepting_nodeids = set()
f = open(self.home, 'rb+')
for (leasenum,lease) in self._enumerate_leases(f):
if lease.renew_secret == renew_secret:
if constant_time_compare(lease.renew_secret, renew_secret):
# yup. See if we need to update the owner time.
if new_expire_time > lease.expiration_time:
# yes
@ -312,7 +313,7 @@ class MutableShareFile:
f = open(self.home, 'rb+')
for (leasenum,lease) in self._enumerate_leases(f):
accepting_nodeids.add(lease.nodeid)
if lease.cancel_secret == cancel_secret:
if constant_time_compare(lease.cancel_secret, cancel_secret):
self._write_lease_record(f, leasenum, blank_lease)
modified += 1
else:
@ -365,7 +366,9 @@ class MutableShareFile:
(real_write_enabler, write_enabler_nodeid) = \
self._read_write_enabler_and_nodeid(f)
f.close()
if write_enabler != real_write_enabler:
# avoid a timing attack
#if write_enabler != real_write_enabler:
if not constant_time_compare(write_enabler, real_write_enabler):
# accomodate share migration by reporting the nodeid used for the
# old write enabler.
self.log(format="bad write enabler on SI %(si)s,"