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Rename 'constant_time_compare' to 'timing_safe_compare'. refs #2165

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Signed-off-by: Daira Hopwood <daira@jacaranda.org>
This commit is contained in:
Daira Hopwood 2014-02-24 20:21:24 +00:00
parent 04ed7d0705
commit d5651a0d0e
4 changed files with 13 additions and 13 deletions
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6
src/allmydata/storage/immutable.py
View File

@ -6,7 +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.util.hashutil import timing_safe_compare
from allmydata.storage.lease import LeaseInfo
from allmydata.storage.common import UnknownImmutableContainerVersionError, \
DataTooLargeError
@ -141,7 +141,7 @@ class ShareFile:
def renew_lease(self, renew_secret, new_expire_time):
for i,lease in enumerate(self.get_leases()):
if constant_time_compare(lease.renew_secret, renew_secret):
if timing_safe_compare(lease.renew_secret, renew_secret):
# yup. See if we need to update the owner time.
if new_expire_time > lease.expiration_time:
# yes
@ -171,7 +171,7 @@ class ShareFile:
leases = list(self.get_leases())
num_leases_removed = 0
for i,lease in enumerate(leases):
if constant_time_compare(lease.cancel_secret, cancel_secret):
if timing_safe_compare(lease.cancel_secret, cancel_secret):
leases[i] = None
num_leases_removed += 1
if not num_leases_removed:

8
src/allmydata/storage/mutable.py
View File

@ -3,7 +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.util.hashutil import timing_safe_compare
from allmydata.storage.lease import LeaseInfo
from allmydata.storage.common import UnknownMutableContainerVersionError, \
DataTooLargeError
@ -290,7 +290,7 @@ class MutableShareFile:
accepting_nodeids = set()
f = open(self.home, 'rb+')
for (leasenum,lease) in self._enumerate_leases(f):
if constant_time_compare(lease.renew_secret, renew_secret):
if timing_safe_compare(lease.renew_secret, renew_secret):
# yup. See if we need to update the owner time.
if new_expire_time > lease.expiration_time:
# yes
@ -336,7 +336,7 @@ class MutableShareFile:
f = open(self.home, 'rb+')
for (leasenum,lease) in self._enumerate_leases(f):
accepting_nodeids.add(lease.nodeid)
if constant_time_compare(lease.cancel_secret, cancel_secret):
if timing_safe_compare(lease.cancel_secret, cancel_secret):
self._write_lease_record(f, leasenum, blank_lease)
modified += 1
else:
@ -391,7 +391,7 @@ class MutableShareFile:
f.close()
# avoid a timing attack
#if write_enabler != real_write_enabler:
if not constant_time_compare(write_enabler, real_write_enabler):
if not timing_safe_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,"

10
src/allmydata/test/test_util.py
View File

@ -659,11 +659,11 @@ class HashUtilTests(unittest.TestCase):
h2.update("foo")
self.failUnlessEqual(h1, h2.digest())
def test_constant_time_compare(self):
self.failUnless(hashutil.constant_time_compare("a", "a"))
self.failUnless(hashutil.constant_time_compare("ab", "ab"))
self.failIf(hashutil.constant_time_compare("a", "b"))
self.failIf(hashutil.constant_time_compare("a", "aa"))
def test_timing_safe_compare(self):
self.failUnless(hashutil.timing_safe_compare("a", "a"))
self.failUnless(hashutil.timing_safe_compare("ab", "ab"))
self.failIf(hashutil.timing_safe_compare("a", "b"))
self.failIf(hashutil.timing_safe_compare("a", "aa"))
def _testknown(self, hashf, expected_a, *args):
got = hashf(*args)

2
src/allmydata/util/hashutil.py
View File

@ -202,7 +202,7 @@ def ssk_readkey_data_hash(IV, readkey):
def ssk_storage_index_hash(readkey):
return tagged_hash(MUTABLE_STORAGEINDEX_TAG, readkey, KEYLEN)
def constant_time_compare(a, b):
def timing_safe_compare(a, b):
n = os.urandom(8)
return bool(tagged_hash(n, a) == tagged_hash(n, b))