def __init__(self, identityStorage, configFilename=None):
"""
:param pyndn.IdentityStorage: A class that stores signing identities and certificates.
:param str configFilename: A configuration file specifying validation rules and network
name settings.
"""
# use the default configuration where possible
# TODO: use environment variable for this, fall back to default
path = os.path.dirname(__file__)
templateFilename = os.path.join(path, '.default.conf')
self._configTemplate = BoostInfoParser()
self._configTemplate.read(templateFilename)
if configFilename is None:
configFilename = templateFilename
certificateCache = CertificateCache()
super(IotPolicyManager, self).__init__(configFilename,
certificateCache)
self._identityStorage = identityStorage
self.setEnvironmentPrefix(None)
self.setTrustRootIdentity(None)
self.setDeviceIdentity(None)
def processConfiguration(self, confFile):
config = BoostInfoParser()
config.read(confFile)
# TODO: handle missing configuration, refactor dict representation
confObj = dict()
try:
confObj["identity"] = config["application/identity"][0].value
confObj["signer"] = config["application/signer"][0].value
except KeyError as e:
msg = "Missing key in configuration: " + str(e)
print msg
return None
return confObj
def __init__(self, configFileName, certificateCache=None,
searchDepth=5, graceInterval=3000, keyTimestampTtl=3600000,
maxTrackedKeys=1000):
super(ConfigPolicyManager, self).__init__()
if certificateCache is None:
self._certificateCache = CertificateCache()
else:
self._certificateCache = certificateCache
self._maxDepth = searchDepth
self._keyGraceInterval = graceInterval
self._keyTimestampTtl = keyTimestampTtl
self._maxTrackedKeys = maxTrackedKeys
# stores the fixed-signer certificate name associated with validation rules
# so we don't keep loading from files
self._fixedCertificateCache = {}
# stores the timestamps for each public key used in command interests to avoid
# replay attacks
# key is public key name, value is last timestamp
self._keyTimestamps = {}
self.config = BoostInfoParser()
self.config.read(configFileName)
self.requiresVerification = True
self._refreshManager = TrustAnchorRefreshManager()
self._loadTrustAnchorCertificates()
def reset(self):
"""
Reset the certificate cache and other fields to the constructor state.
"""
self._certificateCache.reset()
# stores the fixed-signer certificate name associated with validation rules
# so we don't keep loading from files
self._fixedCertificateCache = {}
# stores the timestamps for each public key used in command interests to avoid
# replay attacks
# key is public key name, value is last timestamp
self._keyTimestamps = {}
self.requiresVerification = True
self.config = BoostInfoParser()
self._refreshManager = TrustAnchorRefreshManager()
def reset(self):
"""
Reset the certificate cache and other fields to the constructor state.
"""
self._certificateCache.reset()
# stores the fixed-signer certificate name associated with validation rules
# so we don't keep loading from files
self._fixedCertificateCache = {}
# stores the timestamps for each public key used in command interests to avoid
# replay attacks
# key is public key name, value is last timestamp
self._keyTimestamps = {}
self.requiresVerification = True
self.config = BoostInfoParser()
self._refreshManager = TrustAnchorRefreshManager()
def loadApplications(self, directory=None, override=False):
if not directory:
directory = self._applicationDirectory
if override:
self._applications.clear()
if os.path.exists(directory):
for f in os.listdir(directory):
fullFileName = os.path.join(directory, f)
if os.path.isfile(fullFileName) and f.endswith('.conf'):
appName = f.rstrip('.conf')
if appName in self._applications and not override:
print(
"loadApplications: " + appName +
" already exists, do nothing for configuration file: "
+ fullFileName)
else:
self._applications[appName] = {
"tree": BoostInfoParser(),
"dataPrefix": [],
"version": int(time.time())
}
self._applications[appName]["tree"].read(fullFileName)
data = Data(
Name(self.prefix).append(appName).append(
"_schema").appendVersion(
self._applications[appName]["version"]))
data.setContent(
str(self._applications[appName]["tree"].getRoot()))
self.signData(data)
self._memoryContentCache.add(data)
try:
validatorTree = self._applications[appName][
"tree"]["validator"][0]
for rule in validatorTree["rule"]:
self._applications[appName][
"dataPrefix"].append(rule["id"][0].value)
# TODO: don't swallow any general exceptions, we want to catch only KeyError (make sure) here
except Exception as e:
print(
"loadApplications parse configuration file " +
fullFileName + " : " + str(e))
return
def __init__(self, identityStorage, configFilename=None):
"""
:param pyndn.IdentityStorage: A class that stores signing identities and certificates.
:param str configFilename: A configuration file specifying validation rules and network
name settings.
"""
# use the default configuration where possible
# TODO: use environment variable for this, fall back to default
path = os.path.dirname(__file__)
templateFilename = os.path.join(path, '.default.conf')
self._configTemplate = BoostInfoParser()
self._configTemplate.read(templateFilename)
if configFilename is None:
configFilename = templateFilename
super(IotPolicyManager, self).__init__(identityStorage, configFilename)
self.setEnvironmentPrefix(None)
self.setTrustRootIdentity(None)
self.setDeviceIdentity(None)
self.stop()
else:
self.loop.call_soon(self.displayMenu)
if __name__ == '__main__':
import os
import sys
nArgs = len(sys.argv) - 1
if nArgs == 0:
from pyndn.util.boost_info_parser import BoostInfoParser
fileName = os.path.expanduser('~/.ndn/iot_controller.conf')
config = BoostInfoParser()
config.read(fileName)
deviceName = config["device/controllerName"][0].value
networkName = config["device/environmentPrefix"][0].value
elif nArgs == 2:
networkName = sys.argv[1]
deviceName = sys.argv[2]
else:
print('Usage: {} [network-name controller-name]'.format(sys.argv[0]))
sys.exit(1)
deviceSuffix = Name(deviceName)
networkPrefix = Name(networkName)
n = IotController(deviceSuffix, networkPrefix)
n.start()
class IotPolicyManager(ConfigPolicyManager):
def __init__(self, identityStorage, configFilename=None):
"""
:param pyndn.IdentityStorage: A class that stores signing identities and certificates.
:param str configFilename: A configuration file specifying validation rules and network
name settings.
"""
# use the default configuration where possible
# TODO: use environment variable for this, fall back to default
path = os.path.dirname(__file__)
templateFilename = os.path.join(path, '.default.conf')
self._configTemplate = BoostInfoParser()
self._configTemplate.read(templateFilename)
if configFilename is None:
configFilename = templateFilename
certificateCache = CertificateCache()
super(IotPolicyManager, self).__init__(configFilename, certificateCache)
self._identityStorage = identityStorage
self.setEnvironmentPrefix(None)
self.setTrustRootIdentity(None)
self.setDeviceIdentity(None)
def updateTrustRules(self):
"""
Should be called after either the device identity, trust root or network
prefix is changed.
Not called automatically in case they are all changing (typical for
bootstrapping).
Resets the validation rules if we don't have a trust root or enivronment
"""
validatorTree = self._configTemplate["validator"][0].clone()
if (self._environmentPrefix.size() > 0 and
self._trustRootIdentity.size() > 0 and
self._deviceIdentity.size() > 0):
# don't sneak in a bad identity
if not self._environmentPrefix.match(self._deviceIdentity):
raise SecurityException("Device identity does not belong to configured network!")
environmentUri = self._environmentPrefix.toUri()
deviceUri = self._deviceIdentity.toUri()
for rule in validatorTree["rule"]:
ruleId = rule["id"][0].value
if ruleId == 'Certificate Trust':
#modify the 'Certificate Trust' rule
rule["checker/key-locator/name"][0].value = environmentUri
elif ruleId == 'Command Interests':
rule["filter/name"][0].value = deviceUri
rule["checker/key-locator/name"][0].value = environmentUri
#remove old validation rules from config
# replace with new validator rules
self.config._root.subtrees["validator"] = [validatorTree]
def inferSigningIdentity(self, fromName):
"""
Used to map Data or Interest names to identitites.
:param pyndn.Name fromName: The name of a Data or Interest packet
"""
# works if you have an IotIdentityStorage
return self._identityStorage.inferIdentityForName(fromName)
def setTrustRootIdentity(self, identityName):
"""
: param pyndn.Name identityName: The new identity to trust as the controller.
"""
self._trustRootIdentity = Name(identityName)
def getTrustRootIdentity(self):
"""
: return pyndn.Name: The trusted controller's network name.
"""
return Name(self._trustRootIdentity)
def setEnvironmentPrefix(self, name):
"""
: param pyndn.Name name: The new root of the network namespace (network prefix)
"""
self._environmentPrefix = Name(name)
def getEnvironmentPrefix(self):
"""
:return: The root of the network namespace
:rtype: pyndn.Name
"""
return Name(self._environmentPrefix)
def getDeviceIdentity(self):
return self._deviceIdentity
def setDeviceIdentity(self, identity):
self._deviceIdentity = Name(identity)
def hasRootCertificate(self):
"""
:return: Whether we've downloaded the controller's network certificate
:rtype: boolean
"""
try:
rootCertName = self._identityStorage.getDefaultCertificateNameForIdentity(
self._trustRootIdentity)
except SecurityException:
return False
try:
rootCert = self._identityStorage.getCertificate(rootCertName)
if rootCert is not None:
return True
finally:
return False
def hasRootSignedCertificate(self):
"""
:return: Whether we've received a network certificate from our controller
:rtype: boolean
"""
try:
myCertName = self._identityStorage.getDefaultCertificateNameForIdentity(
self._deviceIdentity)
myCert = self._identityStorage.getCertificate(myCertName)
if self._trustRootIdentity.match(
myCert.getSignature().getKeyLocator().getKeyName()):
return True
except SecurityException:
pass
return False
def removeTrustRules(self):
"""
Resets the network prefix, device identity and trust root identity to
empty values
"""
self.setDeviceIdentity(None)
self.setTrustRootIdentity(None)
self.setEnvironmentPrefix(None)
self.updateTrustRules()
def load(self, filePathOrInputOrConfigSection, inputName=None):
"""
There are three forms of load:
load(filePath) - Load the configuration from the given config file.
load(input, inputName) - Load the configuration from the given input
string.
load(configSection, inputName) - Load the configuration from the given
configSection.
Each of these forms of load replaces any existing configuration.
:param str filePath: The The path of the config file.
:param str input: The contents of the configuration rules, with lines
separated by NL or CR/NL.
:param BoostInfoTree configSection: The configuration section loaded
from the config file. It should have one "validator" section.
:param str inputName: Used for log messages, etc.
"""
if type(filePathOrInputOrConfigSection) is str and inputName == None:
filePath = filePathOrInputOrConfigSection
parser = BoostInfoParser()
parser.read(filePath)
self.load(parser.getRoot(), filePath)
elif (type(filePathOrInputOrConfigSection) is str
and type(inputName) is str):
input = filePathOrInputOrConfigSection
parser = BoostInfoParser()
parser.read(input, inputName)
self.load(parser.getRoot(), inputName)
else:
configSection = filePathOrInputOrConfigSection
if self._isConfigured:
# Reset the previous configuration.
self._shouldBypass = False
self._dataRules = []
self._interestRules = []
self._validator.resetAnchors()
self._validator.resetVerifiedCertificates()
self._isConfigured = True
validatorList = configSection["validator"]
if len(validatorList) != 1:
raise ValidatorConfigError(
"ValidationPolicyConfig: Expected one validator section")
validatorSection = validatorList[0]
# Get the rules.
ruleList = validatorSection["rule"]
for i in range(len(ruleList)):
rule = ConfigRule.create(ruleList[i])
if rule.getIsForInterest():
self._interestRules.append(rule)
else:
self._dataRules.append(rule)
# Get the trust anchors.
trustAnchorList = validatorSection["trust-anchor"]
for i in range(len(trustAnchorList)):
self._processConfigTrustAnchor(trustAnchorList[i], inputName)
class ConfigPolicyManager(PolicyManager):
"""
Create a new ConfigPolicyManager which acts on the rules specified
in the configuration file and downloads unknown certificates when necessary.
:param string configFileName: The path to the configuration file containing
verification rules.
:param CertificateCache certificateCache: (optional) A CertificateCache to
hold known certificates.
:param int searchDepth: (optional) The maximum number of links to follow
when verifying a certificate chain.
:param int graceInterval: (optional) The window of time difference (in
milliseconds) allowed between the timestamp of the first interest signed
with a new public key and the validation time. If omitted, use a default
value.
:param int keyTimestampTtl: (optional) How long a public key's last-used
timestamp is kept in the store (milliseconds). If omitted, use a default
value.
:param int maxTrackedKeys: (optional) The maximum number of public key use
timestamps to track.
"""
def __init__(self, configFileName, certificateCache=None,
searchDepth=5, graceInterval=3000, keyTimestampTtl=3600000,
maxTrackedKeys=1000):
super(ConfigPolicyManager, self).__init__()
if certificateCache is None:
self._certificateCache = CertificateCache()
else:
self._certificateCache = certificateCache
self._maxDepth = searchDepth
self._keyGraceInterval = graceInterval
self._keyTimestampTtl = keyTimestampTtl
self._maxTrackedKeys = maxTrackedKeys
# stores the fixed-signer certificate name associated with validation rules
# so we don't keep loading from files
self._fixedCertificateCache = {}
# stores the timestamps for each public key used in command interests to avoid
# replay attacks
# key is public key name, value is last timestamp
self._keyTimestamps = {}
self.config = BoostInfoParser()
self.config.read(configFileName)
self.requiresVerification = True
self._refreshManager = TrustAnchorRefreshManager()
self._loadTrustAnchorCertificates()
def requireVerify(self, dataOrInterest):
"""
If the configuration file contains the trust anchor 'any',
nothing is verified.
"""
return self.requiresVerification
def checkSigningPolicy(self, dataName, certificateName):
"""
Override to always indicate that the signing certificate name and data
name satisfy the signing policy.
:param Name dataName: The name of data to be signed.
:param Name certificateName: The name of signing certificate.
:return: True to indicate that the signing certificate can be used to
sign the data.
:rtype: boolean
"""
return True
def skipVerifyAndTrust(self, dataOrInterest):
"""
If the configuration file contains the trust anchor 'any',
nothing is verified.
"""
return not self.requiresVerification
def _loadTrustAnchorCertificates(self):
"""
The configuration file allows 'trust anchor' certificates to be preloaded.
The certificates may also be loaded from a directory, and if the 'refresh'
option is set to an interval, the certificates are reloaded at the
specified interval
"""
try:
anchors = self.config["validator/trust-anchor"]
except KeyError:
return
for anchor in anchors:
typeName = anchor["type"][0].getValue()
if typeName == 'file':
certID = anchor["file-name"][0].getValue()
isPath = True
elif typeName == 'base64':
certID = anchor["base64-string"][0].getValue()
isPath = False
elif typeName == "dir":
dirName = anchor["dir"][0].getValue()
try:
refreshPeriodStr = anchor["refresh"][0].getValue()
except KeyError:
refreshPeriod = 0
else:
refreshMatch = re.match('(\d+)([hms])', refreshPeriodStr)
if not refreshMatch:
refreshPeriod = 0
else:
refreshPeriod = int(refreshMatch.group(1))
if refreshMatch.group(2) != 's':
refreshPeriod *= 60
if refreshMatch.group(2) != 'm':
refreshPeriod *= 60
# Convert refreshPeriod from seconds to milliseconds.
self._refreshManager.addDirectory(dirName, refreshPeriod * 1000)
continue
elif typeName == "any":
# this disables all security!
self.requiresVerification = False
break
self._lookupCertificate(certID, isPath)
def _checkSignatureMatch(self, signatureName, objectName, rule):
"""
Once a rule is found to match data or a signed interest, the name in the
KeyLocator must satisfy the condition in the 'checker' section of the rule,
else the data or interest is rejected.
:param Name signatureName: The certificate name from the KeyLocator .
:param Name objectName: The name of the data packet or interest. In the
case of signed interests, this excludes the timestamp, nonce and signature
components.
:param BoostInfoTree rule: The rule from the configuration file that matches
the data or interest.
"""
checker = rule['checker'][0]
checkerType = checker['type'][0].getValue()
if checkerType == 'fixed-signer':
signerInfo = checker['signer'][0]
signerType = signerInfo['type'][0].getValue()
if signerType == 'file':
cert = self._lookupCertificate(signerInfo['file-name'][0].getValue(), True)
elif signerType == 'base64':
cert = self._lookupCertificate(signerInfo['base64-string'][0].getValue(), False)
else:
return False
if cert is None:
return False
else:
return cert.getName().equals(signatureName)
elif checkerType == 'hierarchical':
# this just means the data/interest name has the signing identity as a prefix
# that means everything before 'ksk-?' in the key name
identityRegex = '^([^<KEY>]*)<KEY>(<>*)<ksk-.+><ID-CERT>'
identityMatch = NdnRegexMatcher.match(identityRegex, signatureName)
if identityMatch is not None:
identityPrefix = Name(identityMatch.group(1)).append(Name(identityMatch.group(2)))
return self._matchesRelation(objectName, identityPrefix, 'is-prefix-of')
else:
return False
elif checkerType == 'customized':
keyLocatorInfo = checker['key-locator'][0]
# not checking type - only name is supported
# is this a simple relation?
try:
relationType = keyLocatorInfo['relation'][0].getValue()
except KeyError:
pass
else:
matchName = Name(keyLocatorInfo['name'][0].getValue())
return self._matchesRelation(signatureName, matchName, relationType)
# is this a simple regex?
try:
keyRegex = keyLocatorInfo['regex'][0].getValue()
except KeyError:
pass
else:
return NdnRegexMatcher.match(keyRegex, signatureName) is not None
# is this a hyper-relation?
try:
hyperRelation = keyLocatorInfo['hyper-relation'][0]
except KeyError:
pass
else:
try:
keyRegex = hyperRelation['k-regex'][0].getValue()
keyMatch = NdnRegexMatcher.match(keyRegex, signatureName)
keyExpansion = hyperRelation['k-expand'][0].getValue()
keyMatchPrefix = keyMatch.expand(keyExpansion)
nameRegex = hyperRelation['p-regex'][0].getValue()
nameMatch = NdnRegexMatcher.match(nameRegex, objectName)
nameExpansion = hyperRelation['p-expand'][0].getValue()
nameMatchStr = nameMatch.expand(nameExpansion)
relationType = hyperRelation['h-relation'][0].getValue()
return self._matchesRelation(Name(nameMatchStr), Name(keyMatchPrefix), relationType)
except:
pass
# unknown type
return False
def _lookupCertificate(self, certID, isPath):
"""
This looks up certificates specified as base64-encoded data or file names.
These are cached by filename or encoding to avoid repeated reading of files
or decoding.
"""
try:
certUri = self._fixedCertificateCache[certID]
except KeyError:
if isPath:
# load the certificate data (base64 encoded IdentityCertificate)
cert = TrustAnchorRefreshManager.loadIdentityCertificateFromFile(
certID)
else:
certData = b64decode(certID)
cert = IdentityCertificate()
cert.wireDecode(certData)
certUri = cert.getName()[:-1].toUri()
self._fixedCertificateCache[certID] = certUri
self._certificateCache.insertCertificate(cert)
else:
cert = self._certificateCache.getCertificate(Name(certUri))
return cert
def _findMatchingRule(self, objName, matchType):
"""
Search the configuration file for the first rule that matches the data
or signed interest name. In the case of interests, the name to match
should exclude the timestamp, nonce, and signature components.
:param Name objName: The name to be matched.
:param string matchType: The rule type to match, "data" or "interest".
"""
rules = self.config["validator/rule"]
for r in rules:
if r['for'][0].getValue() == matchType:
passed = True
try:
filters = r['filter']
except KeyError:
# no filters means we pass!
return r
else:
for f in filters:
# don't check the type - it can only be name for now
# we need to see if this is a regex or a relation
try:
regex = f['regex'][0].getValue()
except KeyError:
matchRelation = f['relation'][0].getValue()
matchUri = f['name'][0].getValue()
matchName = Name(matchUri)
passed = self._matchesRelation(objName, matchName, matchRelation)
else:
passed = NdnRegexMatcher.match(regex, objName) is not None
if not passed:
break
if passed:
return r
return None
def _matchesRelation(self, name, matchName, matchRelation):
"""
Determines if a name satisfies the relation to another name, which can
be one of:
'is-prefix-of' - passes if the name is equal to or has the other
name as a prefix
'is-strict-prefix-of' - passes if the name has the other name as a
prefix, and is not equal
'equal' - passes if the two names are equal
"""
passed = False
if matchRelation == 'is-strict-prefix-of':
if matchName.size() == name.size():
passed = False
elif matchName.match(name):
passed = True
elif matchRelation == 'is-prefix-of':
if matchName.match(name):
passed = True
elif matchRelation == 'equal':
if matchName.equals(name):
passed = True
return passed
@staticmethod
def _extractSignature(dataOrInterest, wireFormat=None):
"""
Extract the signature information from the interest name or from the
data packet.
:param dataOrInterest: The object whose signature is needed.
:type dataOrInterest: Data or Interest
:param WireFormat wireFormat: (optional) The wire format used to decode
signature information from the interest name.
"""
if isinstance(dataOrInterest, Data):
return dataOrInterest.getSignature()
elif isinstance(dataOrInterest, Interest):
if wireFormat is None:
# Don't use a default argument since getDefaultWireFormat can change.
wireFormat = WireFormat.getDefaultWireFormat()
try:
signature = wireFormat.decodeSignatureInfoAndValue(
dataOrInterest.getName().get(-2).getValue().buf(),
dataOrInterest.getName().get(-1).getValue().buf())
except (IndexError, ValueError):
return None
return signature
return None
def _interestTimestampIsFresh(self, keyName, timestamp):
"""
Determine whether the timestamp from the interest is newer than the last use
of this key, or within the grace interval on first use.
:param Name keyName: The name of the public key used to sign the interest.
:paramt int timestamp: The timestamp extracted from the interest name.
"""
try:
lastTimestamp = self._keyTimestamps[keyName.toUri()]
except KeyError:
now = Common.getNowMilliseconds()
notBefore = now - self._keyGraceInterval
notAfter = now + self._keyGraceInterval
return timestamp > notBefore and timestamp < notAfter
else:
return timestamp > lastTimestamp
def _updateTimestampForKey(self, keyName, timestamp):
"""
Trim the table size down if necessary, and insert/update the latest
interest signing timestamp for the key.
Any key which has not been used within the TTL period is purged. If the
table is still too large, the oldest key is purged.
:param Name keyName: The name of the public key used to sign the interest.
:paramt int timestamp: The timestamp extracted from the interest name.
"""
self._keyTimestamps[keyName.toUri()] = timestamp
if len(self._keyTimestamps) >= self._maxTrackedKeys:
now = Common.getNowMilliseconds()
oldestTimestamp = now
oldestKey = None
trackedKeys = self._keyTimestamps.keys()
for keyUri in trackedKeys:
ts = self._keyTimestamps[keyUri]
if now - ts > self._keyTimestampTtl:
del self._keyTimestamps[keyUri]
elif ts < oldestTimestamp:
oldestTimestamp = ts
oldestKey = keyUri
if len(self._keyTimestamps) > self._maxTrackedKeys:
# have not removed enough
del self._keyTimestamps[oldestKey]
def checkVerificationPolicy(self, dataOrInterest, stepCount, onVerified,
onVerifyFailed, wireFormat = None):
"""
If there is a rule matching the data or interest, and the matching
certificate is missing, download it. If there is no matching rule,
verification fails. Otherwise, verify the signature using the public key
in the IdentityStorage.
:param dataOrInterest: The Data object or interest with the signature to
check.
:type dataOrInterest: Data or Interest
:param int stepCount: The number of verification steps that have been
done, used to track the verification progress.
:param onVerified: If the signature is verified, this calls
onVerified(dataOrInterest).
:type onVerified: function object
:param onVerifyFailed: If the signature check fails, this calls
onVerifyFailed(dataOrInterest).
:type onVerifyFailed: function object
:return: None for no further step for looking up a certificate chain.
:rtype: ValidationRequest
"""
if stepCount > self._maxDepth:
onVerifyFailed(dataOrInterest)
return None
signature = self._extractSignature(dataOrInterest, wireFormat)
# no signature -> fail
if signature is None:
onVerifyFailed(dataOrInterest)
return None
signatureName = signature.getKeyLocator().getKeyName()
# no key name in KeyLocator -> fail
if signatureName.size() == 0:
onVerifyFailed(dataOrInterest)
return None
objectName = dataOrInterest.getName()
matchType = "data"
#for command interests, we need to ignore the last 4 components when matching the name
if isinstance(dataOrInterest, Interest):
objectName = objectName.getPrefix(-4)
matchType = "interest"
# first see if we can find a rule to match this packet
try:
matchedRule = self._findMatchingRule(objectName, matchType)
except:
matchedRule = None
# no matching rule -> fail
if matchedRule is None:
onVerifyFailed(dataOrInterest)
return None
signatureMatches = self._checkSignatureMatch(signatureName, objectName,
matchedRule)
if not signatureMatches:
onVerifyFailed(dataOrInterest)
return None
# before we look up keys, refresh any certificate directories
self._refreshManager.refreshAnchors()
# now finally check that the data or interest was signed correctly
# if we don't actually have the certificate yet, create a
# ValidationRequest for it
foundCert = self._refreshManager.getCertificate(signatureName)
if foundCert is None:
foundCert = self._certificateCache.getCertificate(signatureName)
if foundCert is None:
certificateInterest = Interest(signatureName)
def onCertificateDownloadComplete(certificate):
certificate = IdentityCertificate(certificate)
self._certificateCache.insertCertificate(certificate)
self.checkVerificationPolicy(dataOrInterest, stepCount+1,
onVerified, onVerifyFailed)
nextStep = ValidationRequest(certificateInterest,
onCertificateDownloadComplete, onVerifyFailed,
2, stepCount+1)
return nextStep
# for interests, we must check that the timestamp is fresh enough
# I do this after (possibly) downloading the certificate to avoid
# filling the cache with bad keys
if isinstance(dataOrInterest, Interest):
keyName = foundCert.getPublicKeyName()
timestamp = dataOrInterest.getName().get(-4).toNumber()
if not self._interestTimestampIsFresh(keyName, timestamp):
onVerifyFailed(dataOrInterest)
return None
# certificate is known, verify the signature
if self._verify(signature, dataOrInterest.wireEncode()):
onVerified(dataOrInterest)
if isinstance(dataOrInterest, Interest):
self._updateTimestampForKey(keyName, timestamp)
else:
onVerifyFailed(dataOrInterest)
def _verify(self, signatureInfo, signedBlob):
"""
Check the type of signatureInfo to get the KeyLocator. Look in the
IdentityStorage for the public key with the name in the KeyLocator and
use it to verify the signedBlob. If the public key can't be found,
return false. (This is a generalized method which can verify both a Data
packet and an interest.)
:param Signature signatureInfo: An object of a subclass of Signature,
e.g. Sha256WithRsaSignature.
:param SignedBlob signedBlob: the SignedBlob with the signed portion to
verify.
:return: True if the signature verifies, False if not.
:rtype: boolean
"""
signature = signatureInfo
if not isinstance(signature, Sha256WithRsaSignature):
raise SecurityException(
"ConfigPolicyManager: Signature is not Sha256WithRsaSignature.")
if (signature.getKeyLocator().getType() == KeyLocatorType.KEYNAME):
# Assume the key name is a certificate name.
signatureName = signature.getKeyLocator().getKeyName()
certificate = self._refreshManager.getCertificate(signatureName)
if certificate is None:
certificate = self._certificateCache.getCertificate(signatureName)
if certificate is None:
return False
publicKeyDer = certificate.getPublicKeyInfo().getKeyDer()
if publicKeyDer.isNull():
# Can't find the public key with the name.
return False
return self._verifySha256WithRsaSignature(
signature, signedBlob, publicKeyDer)
else:
# Can't find a key to verify.
return False
def load(self, filePathOrInputOrConfigSection, inputName = None):
"""
There are three forms of load:
load(filePath) - Load the configuration from the given config file.
load(input, inputName) - Load the configuration from the given input
string.
load(configSection, inputName) - Load the configuration from the given
configSection.
Each of these forms of load replaces any existing configuration.
:param str filePath: The The path of the config file.
:param str input: The contents of the configuration rules, with lines
separated by NL or CR/NL.
:param BoostInfoTree configSection: The configuration section loaded
from the config file. It should have one "validator" section.
:param str inputName: Used for log messages, etc.
"""
if type(filePathOrInputOrConfigSection) is str and inputName == None:
filePath = filePathOrInputOrConfigSection
parser = BoostInfoParser()
parser.read(filePath)
self.load(parser.getRoot(), filePath)
elif (type(filePathOrInputOrConfigSection) is str and
type(inputName) is str):
input = filePathOrInputOrConfigSection
parser = BoostInfoParser()
parser.read(input, inputName)
self.load(parser.getRoot(), inputName)
else:
configSection = filePathOrInputOrConfigSection
if self._isConfigured:
# Reset the previous configuration.
self._shouldBypass = False
self._dataRules = []
self._interestRules = []
self._validator.resetAnchors()
self._validator.resetVerifiedCertificates()
self._isConfigured = True
validatorList = configSection["validator"]
if len(validatorList) != 1:
raise ValidatorConfigError(
"ValidationPolicyConfig: Expected one validator section")
validatorSection = validatorList[0]
# Get the rules.
ruleList = validatorSection["rule"]
for i in range(len(ruleList)):
rule = ConfigRule.create(ruleList[i])
if rule.getIsForInterest():
self._interestRules.append(rule)
else:
self._dataRules.append(rule)
# Get the trust anchors.
trustAnchorList = validatorSection["trust-anchor"]
for i in range(len(trustAnchorList)):
self._processConfigTrustAnchor(trustAnchorList[i], inputName)
def updateTrustSchema(self,
appName,
certName,
dataPrefix,
publishNew=False):
if appName in self._applications:
if dataPrefix.toUri() in self._applications[appName]["dataPrefix"]:
print("some key is configured for namespace " +
dataPrefix.toUri() + " for application " + appName +
". Ignoring this request.")
return False
else:
# TODO: Handle malformed conf where validator tree does not exist
validatorNode = self._applications[appName]["tree"][
"validator"][0]
else:
# This application does not previously exist, we create its trust schema
# (and for now, add in static rules for sync data)
self._applications[appName] = {
"tree": BoostInfoParser(),
"dataPrefix": [],
"version": 0
}
validatorNode = self._applications[appName]["tree"].getRoot(
).createSubtree("validator")
trustAnchorNode = validatorNode.createSubtree("trust-anchor")
#trustAnchorNode.createSubtree("type", "file")
#trustAnchorNode.createSubtree("file-name", os.path.expanduser("~/.ndn/iot/root.cert"))
trustAnchorNode.createSubtree("type", "base64")
trustAnchorNode.createSubtree(
"base64-string",
Blob(b64encode(self._rootCertificate.wireEncode().toBytes()),
False).toRawStr())
#create cert verification rule
# TODO: the idea for this would be, if the cert has /home-prefix/<one-component>/KEY/ksk-*/ID-CERT, then it should be signed by fixed controller(s)
# if the cert has /home-prefix/<multiple-components>/KEY/ksk-*/ID-CERT, then it should be checked hierarchically (this is for subdomain support)
certRuleNode = validatorNode.createSubtree("rule")
certRuleNode.createSubtree("id", "Certs")
certRuleNode.createSubtree("for", "data")
filterNode = certRuleNode.createSubtree("filter")
filterNode.createSubtree("type", "regex")
filterNode.createSubtree("regex", "^[^<KEY>]*<KEY><>*<ID-CERT>")
checkerNode = certRuleNode.createSubtree("checker")
# TODO: wait how did my first hierarchical verifier work?
#checkerNode.createSubtree("type", "hierarchical")
checkerNode.createSubtree("type", "customized")
checkerNode.createSubtree("sig-type", "rsa-sha256")
keyLocatorNode = checkerNode.createSubtree("key-locator")
keyLocatorNode.createSubtree("type", "name")
# We don't put cert version in there
keyLocatorNode.createSubtree(
"name",
Name(self.getDefaultCertificateName()).getPrefix(-1).toUri())
keyLocatorNode.createSubtree("relation", "equal")
# Discovery rule: anything that multicasts under my home prefix should be signed, and the signer should have been authorized by root
# TODO: This rule as of right now is over-general
discoveryRuleNode = validatorNode.createSubtree("rule")
discoveryRuleNode.createSubtree("id", "sync-data")
discoveryRuleNode.createSubtree("for", "data")
filterNode = discoveryRuleNode.createSubtree("filter")
filterNode.createSubtree("type", "regex")
filterNode.createSubtree("regex", "^[^<MULTICAST>]*<MULTICAST><>*")
checkerNode = discoveryRuleNode.createSubtree("checker")
# TODO: wait how did my first hierarchical verifier work?
#checkerNode.createSubtree("type", "hierarchical")
checkerNode.createSubtree("type", "customized")
checkerNode.createSubtree("sig-type", "rsa-sha256")
keyLocatorNode = checkerNode.createSubtree("key-locator")
keyLocatorNode.createSubtree("type", "name")
keyLocatorNode.createSubtree("regex",
"^[^<KEY>]*<KEY><>*<ID-CERT>")
ruleNode = validatorNode.createSubtree("rule")
ruleNode.createSubtree("id", dataPrefix.toUri())
ruleNode.createSubtree("for", "data")
filterNode = ruleNode.createSubtree("filter")
filterNode.createSubtree("type", "name")
filterNode.createSubtree("name", dataPrefix.toUri())
filterNode.createSubtree("relation", "is-prefix-of")
checkerNode = ruleNode.createSubtree("checker")
checkerNode.createSubtree("type", "customized")
checkerNode.createSubtree("sig-type", "rsa-sha256")
keyLocatorNode = checkerNode.createSubtree("key-locator")
keyLocatorNode.createSubtree("type", "name")
# We don't put cert version in there
keyLocatorNode.createSubtree("name", certName.getPrefix(-1).toUri())
keyLocatorNode.createSubtree("relation", "equal")
if not os.path.exists(self._applicationDirectory):
os.makedirs(self._applicationDirectory)
self._applications[appName]["tree"].write(
os.path.join(self._applicationDirectory, appName + ".conf"))
self._applications[appName]["dataPrefix"].append(dataPrefix.toUri())
self._applications[appName]["version"] = int(time.time())
if publishNew:
# TODO: ideally, this is the trust schema of the application, and does not necessarily carry controller prefix.
# We make it carry controller prefix here so that prefix registration / route setup is easier (implementation workaround)
data = Data(
Name(self.prefix).append(appName).append(
"_schema").appendVersion(
self._applications[appName]["version"]))
data.setContent(str(self._applications[appName]["tree"].getRoot()))
self.signData(data)
self._memoryContentCache.add(data)
return True
self.log.debug(msg)
if __name__ == '__main__':
import sys
import os
# todo - should I enforce the suffix 'gateway'?
nArgs = len(sys.argv) - 1
if nArgs < 2:
from pyndn.util.boost_info_parser import BoostInfoParser
fileName = '/usr/local/etc/ndn/iot_controller.conf'
if nArgs == 1:
fileName = sys.argv[1]
try:
config = BoostInfoParser()
config.read(fileName)
except IOError:
print('Could not read {}, exiting...'.format(fileName))
sys.exit(1)
else:
deviceName = config["device/controllerName"][0].value
networkName = config["device/environmentPrefix"][0].value
elif nArgs == 2:
networkName = sys.argv[1]
deviceName = sys.argv[2]
else:
print('Usage: {} [network-name controller-name]'.format(sys.argv[0]))
sys.exit(1)
try:
class IotPolicyManager(ConfigPolicyManager):
def __init__(self, identityStorage, configFilename=None):
"""
:param pyndn.IdentityStorage: A class that stores signing identities and certificates.
:param str configFilename: A configuration file specifying validation rules and network
name settings.
"""
# use the default configuration where possible
# TODO: use environment variable for this, fall back to default
path = os.path.dirname(__file__)
templateFilename = os.path.join(path, '.default.conf')
self._configTemplate = BoostInfoParser()
self._configTemplate.read(templateFilename)
if configFilename is None:
configFilename = templateFilename
certificateCache = CertificateCache()
super(IotPolicyManager, self).__init__(configFilename,
certificateCache)
self._identityStorage = identityStorage
self.setEnvironmentPrefix(None)
self.setTrustRootIdentity(None)
self.setDeviceIdentity(None)
def updateTrustRules(self):
"""
Should be called after either the device identity, trust root or network
prefix is changed.
Not called automatically in case they are all changing (typical for
bootstrapping).
Resets the validation rules if we don't have a trust root or environment
"""
validatorTree = self._configTemplate["validator"][0].clone()
if (self._environmentPrefix.size() > 0
and self._trustRootIdentity.size() > 0
and self._deviceIdentity.size() > 0):
# don't sneak in a bad identity
if not self._environmentPrefix.match(self._deviceIdentity):
raise SecurityException(
"Device identity does not belong to configured network!")
environmentUri = self._environmentPrefix.toUri()
deviceUri = self._deviceIdentity.toUri()
for rule in validatorTree["rule"]:
ruleId = rule["id"][0].value
if ruleId == 'Certificate Trust':
#modify the 'Certificate Trust' rule
rule["checker/key-locator/name"][0].value = environmentUri
elif ruleId == 'Command Interests':
rule["filter/name"][0].value = deviceUri
rule["checker/key-locator/name"][0].value = environmentUri
#debug for adding trust anchor
# try:
# validatorTree["trust-anchor"][0]["type"][0].value = "base64"
# rootCertificate = self._identityStorage.getCertificate(self._identityStorage.getDefaultCertificateNameForIdentity(self._trustRootIdentity))
# validatorTree["trust-anchor"][0]["base64-string"][0].value = Blob(b64encode(rootCertificate.wireEncode().toBytes()), False).toRawStr()
# except KeyError as e:
# rootCertificate = self._identityStorage.getCertificate(self._identityStorage.getDefaultCertificateNameForIdentity(self._trustRootIdentity))
# treeNode = self.config._root.subtrees["validator"][0].createSubtree("trust-anchor")
# # todo: change this!
# treeNode.createSubtree("type", "file")
# print Blob(b64encode(rootCertificate.wireEncode().toBytes()), False).toRawStr()
# treeNode.createSubtree("file-name", "/home/zhehao/.ndn/.iot.root.cert")
# self._loadTrustAnchorCertificates()
#remove old validation rules from config
# replace with new validator rules
self.config._root.subtrees["validator"] = [validatorTree]
def inferSigningIdentity(self, fromName):
"""
Used to map Data or Interest names to identitites.
:param pyndn.Name fromName: The name of a Data or Interest packet
"""
# works if you have an IotIdentityStorage
return self._identityStorage.inferIdentityForName(fromName)
def setTrustRootIdentity(self, identityName):
"""
: param pyndn.Name identityName: The new identity to trust as the controller.
"""
self._trustRootIdentity = Name(identityName)
def getTrustRootIdentity(self):
"""
: return pyndn.Name: The trusted controller's network name.
"""
return Name(self._trustRootIdentity)
def setEnvironmentPrefix(self, name):
"""
: param pyndn.Name name: The new root of the network namespace (network prefix)
"""
self._environmentPrefix = Name(name)
def getEnvironmentPrefix(self):
"""
:return: The root of the network namespace
:rtype: pyndn.Name
"""
return Name(self._environmentPrefix)
def getDeviceIdentity(self):
return self._deviceIdentity
def setDeviceIdentity(self, identity):
self._deviceIdentity = Name(identity)
def hasRootCertificate(self):
"""
:return: Whether we've downloaded the controller's network certificate
:rtype: boolean
"""
try:
rootCertName = self._identityStorage.getDefaultCertificateNameForIdentity(
self._trustRootIdentity)
except SecurityException:
return False
try:
rootCert = self._identityStorage.getCertificate(rootCertName)
if rootCert is not None:
return True
finally:
return False
def hasRootSignedCertificate(self):
"""
:return: Whether we've received a network certificate from our controller
:rtype: boolean
"""
try:
myCertName = self._identityStorage.getDefaultCertificateNameForIdentity(
self._deviceIdentity)
myCert = self._identityStorage.getCertificate(myCertName)
if self._trustRootIdentity.match(
myCert.getSignature().getKeyLocator().getKeyName()):
return True
except SecurityException:
pass
return False
def removeTrustRules(self):
"""
Resets the network prefix, device identity and trust root identity to
empty values
"""
self.setDeviceIdentity(None)
self.setTrustRootIdentity(None)
self.setEnvironmentPrefix(None)
self.updateTrustRules()
class ConfigPolicyManager(PolicyManager):
"""
Create a new ConfigPolicyManager which will act on the rules specified
in the configuration and download unknown certificates when necessary.
:param str configFileName: (optional) If not null or empty, the path to the
configuration file containing verification rules. Otherwise, you should
separately call load().
:param CertificateCache certificateCache: (optional) A CertificateCache to
hold known certificates.
:param int searchDepth: (optional) The maximum number of links to follow
when verifying a certificate chain.
:param int graceInterval: (optional) The window of time difference (in
milliseconds) allowed between the timestamp of the first interest signed
with a new public key and the validation time. If omitted, use a default
value.
:param int keyTimestampTtl: (optional) How long a public key's last-used
timestamp is kept in the store (milliseconds). If omitted, use a default
value.
:param int maxTrackedKeys: (optional) The maximum number of public key use
timestamps to track.
"""
def __init__(self,
configFileName=None,
certificateCache=None,
searchDepth=5,
graceInterval=3000,
keyTimestampTtl=3600000,
maxTrackedKeys=1000):
super(ConfigPolicyManager, self).__init__()
if certificateCache is None:
self._certificateCache = CertificateCache()
else:
self._certificateCache = certificateCache
self._maxDepth = searchDepth
self._keyGraceInterval = graceInterval
self._keyTimestampTtl = keyTimestampTtl
self._maxTrackedKeys = maxTrackedKeys
self.reset()
if configFileName != None and configFileName != "":
self.load(configFileName)
def reset(self):
"""
Reset the certificate cache and other fields to the constructor state.
"""
self._certificateCache.reset()
# stores the fixed-signer certificate name associated with validation rules
# so we don't keep loading from files
self._fixedCertificateCache = {}
# stores the timestamps for each public key used in command interests to avoid
# replay attacks
# key is public key name, value is last timestamp
self._keyTimestamps = {}
self.requiresVerification = True
self.config = BoostInfoParser()
self._refreshManager = TrustAnchorRefreshManager()
def load(self, configFileNameOrInput, inputName=None):
"""
Call reset() and load the configuration rules from the file name or the
input string. There are two forms:
load(configFileName) reads configFileName from the file system.
load(input, inputName) reads from the input, in which case inputName is
used only for log messages, etc.
:param str configFileName: The path to the file containing configuration
rules.
:param str input: The contents of the configuration rules, with lines
separated by NL or CR/NL.
:param str inputName: Use with input for log messages, etc.
"""
self.reset()
self.config.read(configFileNameOrInput, inputName)
self._loadTrustAnchorCertificates()
def requireVerify(self, dataOrInterest):
"""
If the configuration file contains the trust anchor 'any',
nothing is verified.
"""
return self.requiresVerification
def checkSigningPolicy(self, dataName, certificateName):
"""
Override to always indicate that the signing certificate name and data
name satisfy the signing policy.
:param Name dataName: The name of data to be signed.
:param Name certificateName: The name of signing certificate.
:return: True to indicate that the signing certificate can be used to
sign the data.
:rtype: boolean
"""
return True
def skipVerifyAndTrust(self, dataOrInterest):
"""
If the configuration file contains the trust anchor 'any',
nothing is verified.
"""
return not self.requiresVerification
def _loadTrustAnchorCertificates(self):
"""
The configuration file allows 'trust anchor' certificates to be preloaded.
The certificates may also be loaded from a directory, and if the 'refresh'
option is set to an interval, the certificates are reloaded at the
specified interval
"""
try:
anchors = self.config["validator/trust-anchor"]
except KeyError:
return
for anchor in anchors:
typeName = anchor["type"][0].getValue()
if typeName == 'file':
certID = anchor["file-name"][0].getValue()
isPath = True
elif typeName == 'base64':
certID = anchor["base64-string"][0].getValue()
isPath = False
elif typeName == "dir":
dirName = anchor["dir"][0].getValue()
try:
refreshPeriodStr = anchor["refresh"][0].getValue()
except KeyError:
refreshPeriod = 0
else:
refreshMatch = re.match('(\d+)([hms])', refreshPeriodStr)
if not refreshMatch:
refreshPeriod = 0
else:
refreshPeriod = int(refreshMatch.group(1))
if refreshMatch.group(2) != 's':
refreshPeriod *= 60
if refreshMatch.group(2) != 'm':
refreshPeriod *= 60
# Convert refreshPeriod from seconds to milliseconds.
self._refreshManager.addDirectory(dirName,
refreshPeriod * 1000)
continue
elif typeName == "any":
# this disables all security!
self.requiresVerification = False
break
self._lookupCertificate(certID, isPath)
def _checkSignatureMatch(self, signatureName, objectName, rule,
failureReason):
"""
Once a rule is found to match data or a signed interest, the name in the
KeyLocator must satisfy the condition in the 'checker' section of the rule,
else the data or interest is rejected.
:param Name signatureName: The certificate name from the KeyLocator .
:param Name objectName: The name of the data packet or interest. In the
case of signed interests, this excludes the timestamp, nonce and signature
components.
:param BoostInfoTree rule: The rule from the configuration file that matches
the data or interest.
:param Array<str> failureReason: If verification fails, set
failureReason[0] to the failure reason string.
:return: True if matches.
:rtype: bool
"""
checker = rule['checker'][0]
checkerType = checker['type'][0].getValue()
if checkerType == 'fixed-signer':
signerInfo = checker['signer'][0]
signerType = signerInfo['type'][0].getValue()
if signerType == 'file':
cert = self._lookupCertificate(
signerInfo['file-name'][0].getValue(), True)
if cert is None:
failureReason[0] = (
"Can't find fixed-signer certificate file: " +
signerInfo['file-name'][0].getValue())
return False
elif signerType == 'base64':
cert = self._lookupCertificate(
signerInfo['base64-string'][0].getValue(), False)
if cert is None:
failureReason[0] = (
"Can't find fixed-signer certificate base64: " +
signerInfo['base64-string'][0].getValue())
return False
else:
failureReason[0] = ("Unrecognized fixed-signer signerType: " +
signerType)
return False
if cert.getName().equals(signatureName):
return True
else:
failureReason[0] = ("fixed-signer cert name \"" +
cert.getName().toUri() +
"\" does not equal signatureName \"" +
signatureName.toUri() + "\"")
return False
elif checkerType == 'hierarchical':
# this just means the data/interest name has the signing identity as a prefix
# that means everything before 'ksk-?' in the key name
identityRegex = '^([^<KEY>]*)<KEY>(<>*)<ksk-.+><ID-CERT>'
identityMatch = NdnRegexMatcher.match(identityRegex, signatureName)
if identityMatch is not None:
identityPrefix = Name(identityMatch.group(1)).append(
Name(identityMatch.group(2)))
if self._matchesRelation(objectName, identityPrefix,
'is-prefix-of'):
return True
else:
failureReason[0] = ("The hierarchical objectName \"" +
objectName.toUri() +
"\" is not a prefix of \"" +
identityPrefix.toUri() + "\"")
return False
else:
failureReason[0] = ("The hierarchical identityRegex \"" +
identityRegex +
"\" does not match signatureName \"" +
signatureName.toUri() + "\"")
return False
elif checkerType == 'customized':
keyLocatorInfo = checker['key-locator'][0]
# not checking type - only name is supported
# is this a simple relation?
try:
relationType = keyLocatorInfo['relation'][0].getValue()
except KeyError:
pass
else:
matchName = Name(keyLocatorInfo['name'][0].getValue())
if self._matchesRelation(signatureName, matchName,
relationType):
return True
else:
failureReason[0] = ("The custom signatureName \"" +
signatureName.toUri() +
"\" does not match matchName \"" +
matchName.toUri() +
"\" using relation " + relationType)
return False
# is this a simple regex?
try:
keyRegex = keyLocatorInfo['regex'][0].getValue()
except KeyError:
pass
else:
if NdnRegexMatcher.match(keyRegex, signatureName) is not None:
return True
else:
failureReason[0] = (
"The custom signatureName \"" + signatureName.toUri() +
"\" does not regex match simpleKeyRegex \"" +
keyRegex + "\"")
return False
# is this a hyper-relation?
try:
hyperRelation = keyLocatorInfo['hyper-relation'][0]
except KeyError:
pass
else:
keyRegex = hyperRelation.getFirstValue('k-regex')
keyExpansion = hyperRelation.getFirstValue('k-expand')
nameRegex = hyperRelation.getFirstValue('p-regex')
nameExpansion = hyperRelation.getFirstValue('p-expand')
relationType = hyperRelation.getFirstValue('h-relation')
if (keyRegex != None and keyExpansion != None
and nameRegex != None and nameExpansion != None
and relationType != None):
keyMatch = NdnRegexMatcher.match(keyRegex, signatureName)
if keyMatch == None:
failureReason[0] = (
"The custom hyper-relation signatureName \"" +
signatureName.toUri() +
"\" does not match the keyRegex \"" + keyRegex +
"\"")
return False
keyMatchPrefix = keyMatch.expand(keyExpansion)
nameMatch = NdnRegexMatcher.match(nameRegex, objectName)
if nameMatch == None:
failureReason[0] = (
"The custom hyper-relation objectName \"" +
objectName.toUri() +
"\" does not match the nameRegex \"" + nameRegex +
"\"")
return False
nameMatchStr = nameMatch.expand(nameExpansion)
if self._matchesRelation(Name(nameMatchStr),
Name(keyMatchPrefix),
relationType):
return True
else:
failureReason[0] = (
"The custom hyper-relation nameMatch \"" +
nameMatchStr +
"\" does not match the keyMatchPrefix \"" +
keyMatchPrefix + "\" using relation " +
relationType)
return False
failureReason[0] = "Unrecognized checkerType: " + checkerType
return False
def _lookupCertificate(self, certID, isPath):
"""
This looks up certificates specified as base64-encoded data or file names.
These are cached by filename or encoding to avoid repeated reading of files
or decoding.
:return: The certificate object, or None if not found.
:rtype: IdentityCertificate
"""
try:
certUri = self._fixedCertificateCache[certID]
except KeyError:
if isPath:
# load the certificate data (base64 encoded IdentityCertificate)
cert = TrustAnchorRefreshManager.loadIdentityCertificateFromFile(
certID)
else:
certData = b64decode(certID)
cert = IdentityCertificate()
cert.wireDecode(Blob(certData, False))
certUri = cert.getName()[:-1].toUri()
self._fixedCertificateCache[certID] = certUri
self._certificateCache.insertCertificate(cert)
else:
cert = self._certificateCache.getCertificate(Name(certUri))
return cert
def _findMatchingRule(self, objName, matchType):
"""
Search the configuration file for the first rule that matches the data
or signed interest name. In the case of interests, the name to match
should exclude the timestamp, nonce, and signature components.
:param Name objName: The name to be matched.
:param string matchType: The rule type to match, "data" or "interest".
"""
rules = self.config["validator/rule"]
for r in rules:
if r['for'][0].getValue() == matchType:
passed = True
try:
filters = r['filter']
except KeyError:
# no filters means we pass!
return r
else:
for f in filters:
# don't check the type - it can only be name for now
# we need to see if this is a regex or a relation
try:
regex = f['regex'][0].getValue()
except KeyError:
matchRelation = f['relation'][0].getValue()
matchUri = f['name'][0].getValue()
matchName = Name(matchUri)
passed = self._matchesRelation(
objName, matchName, matchRelation)
else:
passed = NdnRegexMatcher.match(regex,
objName) is not None
if not passed:
break
if passed:
return r
return None
@staticmethod
def _matchesRelation(name, matchName, matchRelation):
"""
Determines if a name satisfies the relation to another name, which can
be one of:
'is-prefix-of' - passes if the name is equal to or has the other
name as a prefix
'is-strict-prefix-of' - passes if the name has the other name as a
prefix, and is not equal
'equal' - passes if the two names are equal
"""
passed = False
if matchRelation == 'is-strict-prefix-of':
if matchName.size() == name.size():
passed = False
elif matchName.match(name):
passed = True
elif matchRelation == 'is-prefix-of':
if matchName.match(name):
passed = True
elif matchRelation == 'equal':
if matchName.equals(name):
passed = True
return passed
@staticmethod
def _extractSignature(dataOrInterest, wireFormat=None):
"""
Extract the signature information from the interest name or from the
data packet.
:param dataOrInterest: The object whose signature is needed.
:type dataOrInterest: Data or Interest
:param WireFormat wireFormat: (optional) The wire format used to decode
signature information from the interest name.
"""
if isinstance(dataOrInterest, Data):
return dataOrInterest.getSignature()
elif isinstance(dataOrInterest, Interest):
if wireFormat is None:
# Don't use a default argument since getDefaultWireFormat can change.
wireFormat = WireFormat.getDefaultWireFormat()
try:
signature = wireFormat.decodeSignatureInfoAndValue(
dataOrInterest.getName().get(-2).getValue().buf(),
dataOrInterest.getName().get(-1).getValue().buf(), False)
except (IndexError, ValueError):
return None
return signature
return None
def _interestTimestampIsFresh(self, keyName, timestamp, failureReason):
"""
Determine whether the timestamp from the interest is newer than the last use
of this key, or within the grace interval on first use.
:param Name keyName: The name of the public key used to sign the interest.
:paramt int timestamp: The timestamp extracted from the interest name.
:param Array<str> failureReason: If verification fails, set
failureReason[0] to the failure reason string.
"""
try:
lastTimestamp = self._keyTimestamps[keyName.toUri()]
except KeyError:
now = Common.getNowMilliseconds()
notBefore = now - self._keyGraceInterval
notAfter = now + self._keyGraceInterval
if not (timestamp > notBefore and timestamp < notAfter):
return False
failureReason[0] = (
"The command interest timestamp is not within the first use grace period of "
+ str(self._keyGraceInterval) + " milliseconds.")
else:
return True
else:
if timestamp <= lastTimestamp:
failureReason[0] = (
"The command interest timestamp is not newer than the previous timestamp"
)
return False
else:
return True
def _updateTimestampForKey(self, keyName, timestamp):
"""
Trim the table size down if necessary, and insert/update the latest
interest signing timestamp for the key.
Any key which has not been used within the TTL period is purged. If the
table is still too large, the oldest key is purged.
:param Name keyName: The name of the public key used to sign the interest.
:paramt int timestamp: The timestamp extracted from the interest name.
"""
self._keyTimestamps[keyName.toUri()] = timestamp
if len(self._keyTimestamps) >= self._maxTrackedKeys:
now = Common.getNowMilliseconds()
oldestTimestamp = now
oldestKey = None
trackedKeys = self._keyTimestamps.keys()
for keyUri in trackedKeys:
ts = self._keyTimestamps[keyUri]
if now - ts > self._keyTimestampTtl:
del self._keyTimestamps[keyUri]
elif ts < oldestTimestamp:
oldestTimestamp = ts
oldestKey = keyUri
if len(self._keyTimestamps) > self._maxTrackedKeys:
# have not removed enough
del self._keyTimestamps[oldestKey]
def checkVerificationPolicy(self,
dataOrInterest,
stepCount,
onVerified,
onValidationFailed,
wireFormat=None):
"""
If there is a rule matching the data or interest, and the matching
certificate is missing, download it. If there is no matching rule,
verification fails. Otherwise, verify the signature using the public key
in the IdentityStorage.
:param dataOrInterest: The Data object or interest with the signature to
check.
:type dataOrInterest: Data or Interest
:param int stepCount: The number of verification steps that have been
done, used to track the verification progress.
:param onVerified: If the signature is verified, this calls
onVerified(dataOrInterest).
NOTE: The library will log any exceptions raised by this callback, but
for better error handling the callback should catch and properly
handle any exceptions.
:type onVerified: function object
:param onValidationFailed: If the signature check fails, this calls
onValidationFailed(dataOrInterest, reason).
NOTE: The library will log any exceptions raised by this callback, but
for better error handling the callback should catch and properly
handle any exceptions.
:type onValidationFailed: function object
:return: None for no further step for looking up a certificate chain.
:rtype: ValidationRequest
"""
if stepCount > self._maxDepth:
try:
onValidationFailed(
dataOrInterest, "The verification stepCount " + stepCount +
" exceeded the maxDepth " + self._maxDepth)
except:
logging.exception("Error in onValidationFailed")
return None
signature = self._extractSignature(dataOrInterest, wireFormat)
# no signature -> fail
if signature is None:
try:
onValidationFailed(
dataOrInterest, "Cannot extract the signature from " +
dataOrInterest.getName().toUri())
except:
logging.exception("Error in onValidationFailed")
return None
if not KeyLocator.canGetFromSignature(signature):
# We only support signature types with key locators.
try:
onValidationFailed(
dataOrInterest,
"The signature type does not support a KeyLocator")
except:
logging.exception("Error in onValidationFailed")
return None
keyLocator = None
try:
keyLocator = KeyLocator.getFromSignature(signature)
except Exception as ex:
# No key locator -> fail.
try:
onValidationFailed(
dataOrInterest,
"Error in KeyLocator.getFromSignature: " + str(ex))
except:
logging.exception("Error in onValidationFailed")
return None
signatureName = keyLocator.getKeyName()
# no key name in KeyLocator -> fail
if signatureName.size() == 0:
try:
onValidationFailed(
dataOrInterest,
"The signature KeyLocator doesn't have a key name")
except:
logging.exception("Error in onValidationFailed")
return None
objectName = dataOrInterest.getName()
matchType = "data"
#for command interests, we need to ignore the last 4 components when matching the name
if isinstance(dataOrInterest, Interest):
objectName = objectName.getPrefix(-4)
matchType = "interest"
# first see if we can find a rule to match this packet
try:
matchedRule = self._findMatchingRule(objectName, matchType)
except:
matchedRule = None
# no matching rule -> fail
if matchedRule is None:
try:
onValidationFailed(
dataOrInterest,
"No matching rule found for " + objectName.toUri())
except:
logging.exception("Error in onValidationFailed")
return None
failureReason = ["unknown"]
signatureMatches = self._checkSignatureMatch(signatureName, objectName,
matchedRule,
failureReason)
if not signatureMatches:
try:
onValidationFailed(dataOrInterest, failureReason[0])
except:
logging.exception("Error in onValidationFailed")
return None
# before we look up keys, refresh any certificate directories
self._refreshManager.refreshAnchors()
# now finally check that the data or interest was signed correctly
# if we don't actually have the certificate yet, create a
# ValidationRequest for it
foundCert = self._refreshManager.getCertificate(signatureName)
if foundCert is None:
foundCert = self._certificateCache.getCertificate(signatureName)
if foundCert is None:
certificateInterest = Interest(signatureName)
def onCertificateDownloadComplete(data):
try:
certificate = IdentityCertificate(data)
except:
try:
onValidationFailed(
dataOrInterest, "Cannot decode certificate " +
data.getName().toUri())
except:
logging.exception("Error in onValidationFailed")
return None
self._certificateCache.insertCertificate(certificate)
self.checkVerificationPolicy(dataOrInterest, stepCount + 1,
onVerified, onValidationFailed)
nextStep = ValidationRequest(certificateInterest,
onCertificateDownloadComplete,
onValidationFailed, 2, stepCount + 1)
return nextStep
# for interests, we must check that the timestamp is fresh enough
# I do this after (possibly) downloading the certificate to avoid
# filling the cache with bad keys
if isinstance(dataOrInterest, Interest):
keyName = foundCert.getPublicKeyName()
timestamp = dataOrInterest.getName().get(-4).toNumber()
if not self._interestTimestampIsFresh(keyName, timestamp,
failureReason):
try:
onValidationFailed(dataOrInterest, failureReason[0])
except:
logging.exception("Error in onValidationFailed")
return None
# certificate is known, verify the signature
if self._verify(signature, dataOrInterest.wireEncode(), failureReason):
try:
onVerified(dataOrInterest)
except:
logging.exception("Error in onVerified")
if isinstance(dataOrInterest, Interest):
self._updateTimestampForKey(keyName, timestamp)
else:
try:
onValidationFailed(dataOrInterest, failureReason[0])
except:
logging.exception("Error in onValidationFailed")
def _verify(self, signatureInfo, signedBlob, failureReason):
"""
Check the type of signatureInfo to get the KeyLocator. Look in the
IdentityStorage for the public key with the name in the KeyLocator and
use it to verify the signedBlob. If the public key can't be found,
return false. (This is a generalized method which can verify both a Data
packet and an interest.)
:param Signature signatureInfo: An object of a subclass of Signature,
e.g. Sha256WithRsaSignature.
:param SignedBlob signedBlob: the SignedBlob with the signed portion to
verify.
:param Array<str> failureReason: If verification fails, set
failureReason[0] to the failure reason string.
:return: True if the signature verifies, False if not.
:rtype: boolean
"""
# We have already checked once that there is a key locator.
keyLocator = KeyLocator.getFromSignature(signatureInfo)
if (keyLocator.getType() == KeyLocatorType.KEYNAME):
# Assume the key name is a certificate name.
signatureName = keyLocator.getKeyName()
certificate = self._refreshManager.getCertificate(signatureName)
if certificate is None:
certificate = self._certificateCache.getCertificate(
signatureName)
if certificate is None:
failureReason[0] = ("Cannot find a certificate with name " +
signatureName.toUri())
return False
publicKeyDer = certificate.getPublicKeyInfo().getKeyDer()
if publicKeyDer.isNull():
# We don't expect this to happen.
failureReason[0] = (
"There is no public key in the certificate with name " +
certificate.getName().toUri())
return False
if self.verifySignature(signatureInfo, signedBlob, publicKeyDer):
return True
else:
failureReason[0] = (
"The signature did not verify with the given public key")
return False
else:
failureReason[0] = "The KeyLocator does not have a key name"
return False
class ConfigPolicyManager(PolicyManager):
"""
Create a new ConfigPolicyManager which will act on the rules specified
in the configuration and download unknown certificates when necessary.
If certificateCache is a CertificateCache (or omitted) this creates a
security v1 PolicyManager to verify certificates in format v1. To verify
certificates in format v2, use a CertificateCacheV2 for the certificateCache.
:param str configFileName: (optional) If not None or empty, the path to the
configuration file containing verification rules. Otherwise, you should
separately call load().
:param certificateCache: (optional) A CertificateCache to hold known
certificates. If certificateCache is a CertificateCache (or omitted
or None) this creates a security v1 PolicyManager to verify certificates
in format v1. If this is a CertificateCacheV2, verify certificates in
format v2. If omitted or None, create an internal v1 CertificateCache.
:type certificateCache: CertificateCache or CertificateCacheV2
:param int searchDepth: (optional) The maximum number of links to follow
when verifying a certificate chain.
:param int graceInterval: (optional) The window of time difference (in
milliseconds) allowed between the timestamp of the first interest signed
with a new public key and the validation time. If omitted, use a default
value.
:param int keyTimestampTtl: (optional) How long a public key's last-used
timestamp is kept in the store (milliseconds). If omitted, use a default
value.
:param int maxTrackedKeys: (optional) The maximum number of public key use
timestamps to track.
"""
def __init__(self, configFileName = None, certificateCache = None,
searchDepth=5, graceInterval=3000, keyTimestampTtl=3600000,
maxTrackedKeys=1000):
super(ConfigPolicyManager, self).__init__()
if certificateCache is None:
certificateCache = CertificateCache()
# _certificateCacheV2 will be replaced below, but set it here to make pylint happy.
self._certificateCacheV2 = CertificateCacheV2()
if isinstance(certificateCache, CertificateCache):
self._isSecurityV1 = True
self._certificateCache = certificateCache
self._certificateCacheV2 = None
else:
self._isSecurityV1 = False
self._certificateCache = None
self._certificateCacheV2 = certificateCache
self._maxDepth = searchDepth
self._keyGraceInterval = graceInterval
self._keyTimestampTtl = keyTimestampTtl
self._maxTrackedKeys = maxTrackedKeys
self.reset()
if configFileName != None and configFileName != "":
self.load(configFileName)
def reset(self):
"""
Reset the certificate cache and other fields to the constructor state.
"""
if self._isSecurityV1:
self._certificateCache.reset()
else:
self._certificateCacheV2.clear()
# stores the fixed-signer certificate name associated with validation rules
# so we don't keep loading from files
self._fixedCertificateCache = {}
# stores the timestamps for each public key used in command interests to avoid
# replay attacks
# key is public key name, value is last timestamp
self._keyTimestamps = {}
self.requiresVerification = True
self.config = BoostInfoParser()
self._refreshManager = TrustAnchorRefreshManager(self._isSecurityV1)
def load(self, configFileNameOrInput, inputName = None):
"""
Call reset() and load the configuration rules from the file name or the
input string. There are two forms:
load(configFileName) reads configFileName from the file system.
load(input, inputName) reads from the input, in which case inputName is
used only for log messages, etc.
:param str configFileName: The path to the file containing configuration
rules.
:param str input: The contents of the configuration rules, with lines
separated by NL or CR/NL.
:param str inputName: Use with input for log messages, etc.
"""
self.reset()
self.config.read(configFileNameOrInput, inputName)
self._loadTrustAnchorCertificates()
def requireVerify(self, dataOrInterest):
"""
If the configuration file contains the trust anchor 'any',
nothing is verified.
"""
return self.requiresVerification
def checkSigningPolicy(self, dataName, certificateName):
"""
Override to always indicate that the signing certificate name and data
name satisfy the signing policy.
:param Name dataName: The name of data to be signed.
:param Name certificateName: The name of signing certificate.
:return: True to indicate that the signing certificate can be used to
sign the data.
:rtype: boolean
"""
return True
def skipVerifyAndTrust(self, dataOrInterest):
"""
If the configuration file contains the trust anchor 'any',
nothing is verified.
"""
return not self.requiresVerification
def _loadTrustAnchorCertificates(self):
"""
The configuration file allows 'trust anchor' certificates to be preloaded.
The certificates may also be loaded from a directory, and if the 'refresh'
option is set to an interval, the certificates are reloaded at the
specified interval
"""
try:
anchors = self.config["validator/trust-anchor"]
except KeyError:
return
for anchor in anchors:
typeName = anchor["type"][0].getValue()
if typeName == 'file':
certID = anchor["file-name"][0].getValue()
isPath = True
elif typeName == 'base64':
certID = anchor["base64-string"][0].getValue()
isPath = False
elif typeName == "dir":
dirName = anchor["dir"][0].getValue()
try:
refreshPeriodStr = anchor["refresh"][0].getValue()
except KeyError:
refreshPeriod = 0
else:
refreshMatch = re.match('(\\d+)([hms])', refreshPeriodStr)
if not refreshMatch:
refreshPeriod = 0
else:
refreshPeriod = int(refreshMatch.group(1))
if refreshMatch.group(2) != 's':
refreshPeriod *= 60
if refreshMatch.group(2) != 'm':
refreshPeriod *= 60
# Convert refreshPeriod from seconds to milliseconds.
self._refreshManager.addDirectory(dirName, refreshPeriod * 1000)
continue
elif typeName == "any":
# this disables all security!
self.requiresVerification = False
break
if self._isSecurityV1:
self._lookupCertificate(certID, isPath)
else:
self._lookupCertificateV2(certID, isPath)
def _checkSignatureMatch(self, signatureName, objectName, rule, failureReason):
"""
Once a rule is found to match data or a signed interest, the name in the
KeyLocator must satisfy the condition in the 'checker' section of the rule,
else the data or interest is rejected.
:param Name signatureName: The certificate name from the KeyLocator .
:param Name objectName: The name of the data packet or interest. In the
case of signed interests, this excludes the timestamp, nonce and signature
components.
:param BoostInfoTree rule: The rule from the configuration file that matches
the data or interest.
:param Array<str> failureReason: If verification fails, set
failureReason[0] to the failure reason string.
:return: True if matches.
:rtype: bool
"""
checker = rule['checker'][0]
checkerType = checker['type'][0].getValue()
if checkerType == 'fixed-signer':
signerInfo = checker['signer'][0]
signerType = signerInfo['type'][0].getValue()
if signerType == 'file':
if self._isSecurityV1:
cert = self._lookupCertificate(
signerInfo['file-name'][0].getValue(), True)
if cert is None:
failureReason[0] = (
"Can't find fixed-signer certificate file: " +
signerInfo['file-name'][0].getValue())
return False
else:
cert = self._lookupCertificateV2(
signerInfo['file-name'][0].getValue(), True)
if cert is None:
failureReason[0] = (
"Can't find fixed-signer certificate file: " +
signerInfo['file-name'][0].getValue())
return False
elif signerType == 'base64':
if self._isSecurityV1:
cert = self._lookupCertificate(
signerInfo['base64-string'][0].getValue(), False)
if cert is None:
failureReason[0] = (
"Can't find fixed-signer certificate base64: " +
signerInfo['base64-string'][0].getValue())
return False
else:
cert = self._lookupCertificateV2(
signerInfo['base64-string'][0].getValue(), False)
if cert is None:
failureReason[0] = (
"Can't find fixed-signer certificate base64: " +
signerInfo['base64-string'][0].getValue())
return False
else:
failureReason[0] = ("Unrecognized fixed-signer signerType: " +
signerType)
return False
if cert.getName().equals(signatureName):
return True
else:
failureReason[0] = ("fixed-signer cert name \"" +
cert.getName().toUri() + "\" does not equal signatureName \"" +
signatureName.toUri() + "\"")
return False
elif checkerType == 'hierarchical':
# this just means the data/interest name has the signing identity as a prefix
# that means everything before 'ksk-?' in the key name
identityRegex = '^([^<KEY>]*)<KEY>(<>*)<ksk-.+><ID-CERT>'
identityMatch = NdnRegexTopMatcher(identityRegex)
if identityMatch.match(signatureName):
identityPrefix = identityMatch.expand("\\1").append(
identityMatch.expand("\\2"))
if self._matchesRelation(objectName, identityPrefix, 'is-prefix-of'):
return True
else:
failureReason[0] = ("The hierarchical objectName \"" +
objectName.toUri() + "\" is not a prefix of \"" +
identityPrefix.toUri() + "\"")
return False
if not self._isSecurityV1:
# Check for a security v2 key name.
identityRegex2 = "^(<>*)<KEY><>$"
identityMatch2 = NdnRegexTopMatcher(identityRegex2)
if identityMatch2.match(signatureName):
identityPrefix = identityMatch2.expand("\\1")
if self._matchesRelation(objectName, identityPrefix, 'is-prefix-of'):
return True
else:
failureReason[0] = ("The hierarchical objectName \"" +
objectName.toUri() + "\" is not a prefix of \"" +
identityPrefix.toUri() + "\"")
return False
failureReason[0] = ("The hierarchical identityRegex \"" +
identityRegex + "\" does not match signatureName \"" +
signatureName.toUri() + "\"")
return False
elif checkerType == 'customized':
keyLocatorInfo = checker['key-locator'][0]
# not checking type - only name is supported
# is this a simple relation?
relationType = keyLocatorInfo.getFirstValue("relation")
if relationType != None:
matchName = Name(keyLocatorInfo['name'][0].getValue())
if self._matchesRelation(signatureName, matchName, relationType):
return True
else:
failureReason[0] = ("The custom signatureName \"" +
signatureName.toUri() + "\" does not match matchName \"" +
matchName.toUri() + "\" using relation " + relationType)
return False
# Is this a simple regex?
simpleKeyRegex = keyLocatorInfo.getFirstValue("regex")
if simpleKeyRegex != None:
if NdnRegexTopMatcher(simpleKeyRegex).match(signatureName):
return True
else:
failureReason[0] = ("The custom signatureName \"" +
signatureName.toUri() +
"\" does not regex match simpleKeyRegex \"" +
simpleKeyRegex + "\"")
return False
# is this a hyper-relation?
hyperRelationList = keyLocatorInfo["hyper-relation"]
if len(hyperRelationList) >= 1:
hyperRelation = hyperRelationList[0]
keyRegex = hyperRelation.getFirstValue('k-regex')
keyExpansion = hyperRelation.getFirstValue('k-expand')
nameRegex = hyperRelation.getFirstValue('p-regex')
nameExpansion = hyperRelation.getFirstValue('p-expand')
relationType = hyperRelation.getFirstValue('h-relation')
if (keyRegex != None and keyExpansion != None and
nameRegex != None and nameExpansion != None and
relationType != None):
keyMatch = NdnRegexTopMatcher(keyRegex)
if not keyMatch.match(signatureName):
failureReason[0] = (
"The custom hyper-relation signatureName \"" +
signatureName.toUri() +
"\" does not match the keyRegex \"" + keyRegex + "\"")
return False
keyMatchPrefix = keyMatch.expand(keyExpansion)
nameMatch = NdnRegexTopMatcher(nameRegex)
if not nameMatch.match(objectName):
failureReason[0] = (
"The custom hyper-relation objectName \"" +
objectName.toUri() +
"\" does not match the nameRegex \"" + nameRegex + "\"")
return False
nameMatchExpansion = nameMatch.expand(nameExpansion)
if self._matchesRelation(
nameMatchExpansion, keyMatchPrefix, relationType):
return True
else:
failureReason[0] = (
"The custom hyper-relation nameMatch \"" +
nameMatchExpansion.toUri() +
"\" does not match the keyMatchPrefix \"" +
keyMatchPrefix.toUri() + "\" using relation " +
relationType)
return False
failureReason[0] = "Unrecognized checkerType: " + checkerType
return False
def _lookupCertificate(self, certID, isPath):
"""
This looks up certificates specified as base64-encoded data or file names.
These are cached by filename or encoding to avoid repeated reading of files
or decoding.
:return: The certificate object, or None if not found.
:rtype: IdentityCertificate
"""
if not self._isSecurityV1:
raise SecurityException(
"lookupCertificate: For security v2, use lookupCertificateV2()")
try:
certUri = self._fixedCertificateCache[certID]
except KeyError:
if isPath:
# load the certificate data (base64 encoded IdentityCertificate)
cert = TrustAnchorRefreshManager.loadIdentityCertificateFromFile(
certID)
else:
certData = b64decode(certID)
cert = IdentityCertificate()
cert.wireDecode(Blob(certData, False))
certUri = cert.getName()[:-1].toUri()
self._fixedCertificateCache[certID] = certUri
self._certificateCache.insertCertificate(cert)
else:
cert = self._certificateCache.getCertificate(Name(certUri))
return cert
def _lookupCertificateV2(self, certID, isPath):
"""
This looks up certificates specified as base64-encoded data or file
names. These are cached by filename or encoding to avoid repeated
reading of files or decoding.
:return: The CertificateV2, or None if not found.
:rtype: CertificateV2
"""
if self._isSecurityV1:
raise SecurityException(
"lookupCertificateV2: For security v1, use lookupCertificate()")
try:
certUri = self._fixedCertificateCache[certID]
except KeyError:
if isPath:
# load the certificate data (base64 encoded IdentityCertificate)
cert = TrustAnchorRefreshManager.loadCertificateV2FromFile(
certID)
else:
certData = b64decode(certID)
cert = CertificateV2()
cert.wireDecode(Blob(certData, False))
certUri = cert.getName()[:-1].toUri()
self._fixedCertificateCache[certID] = certUri
self._certificateCacheV2.insert(cert)
else:
cert = self._certificateCacheV2.find(Name(certUri))
return cert
def _findMatchingRule(self, objName, matchType):
"""
Search the configuration file for the first rule that matches the data
or signed interest name. In the case of interests, the name to match
should exclude the timestamp, nonce, and signature components.
:param Name objName: The name to be matched.
:param string matchType: The rule type to match, "data" or "interest".
"""
rules = self.config["validator/rule"]
for r in rules:
if r['for'][0].getValue() == matchType:
passed = True
try:
filters = r['filter']
except KeyError:
# no filters means we pass!
return r
else:
for f in filters:
# don't check the type - it can only be name for now
# we need to see if this is a regex or a relation
regexPattern = f.getFirstValue("regex")
if regexPattern == None:
matchRelation =f.getFirstValue("relation")
matchUri = f.getFirstValue("name")
matchName = Name(matchUri)
passed = self._matchesRelation(objName, matchName, matchRelation)
else:
passed = NdnRegexTopMatcher(regexPattern).match(objName)
if not passed:
break
if passed:
return r
return None
@staticmethod
def _matchesRelation(name, matchName, matchRelation):
"""
Determines if a name satisfies the relation to another name, which can
be one of:
'is-prefix-of' - passes if the name is equal to or has the other
name as a prefix
'is-strict-prefix-of' - passes if the name has the other name as a
prefix, and is not equal
'equal' - passes if the two names are equal
"""
passed = False
if matchRelation == 'is-strict-prefix-of':
if matchName.size() == name.size():
passed = False
elif matchName.match(name):
passed = True
elif matchRelation == 'is-prefix-of':
if matchName.match(name):
passed = True
elif matchRelation == 'equal':
if matchName.equals(name):
passed = True
return passed
@staticmethod
def _extractSignature(dataOrInterest, wireFormat=None):
"""
Extract the signature information from the interest name or from the
data packet.
:param dataOrInterest: The object whose signature is needed.
:type dataOrInterest: Data or Interest
:param WireFormat wireFormat: (optional) The wire format used to decode
signature information from the interest name.
"""
if isinstance(dataOrInterest, Data):
return dataOrInterest.getSignature()
elif isinstance(dataOrInterest, Interest):
if wireFormat is None:
# Don't use a default argument since getDefaultWireFormat can change.
wireFormat = WireFormat.getDefaultWireFormat()
try:
signature = wireFormat.decodeSignatureInfoAndValue(
dataOrInterest.getName().get(-2).getValue().buf(),
dataOrInterest.getName().get(-1).getValue().buf(), False)
except (IndexError, ValueError):
return None
return signature
return None
def _interestTimestampIsFresh(self, keyName, timestamp, failureReason):
"""
Determine whether the timestamp from the interest is newer than the last use
of this key, or within the grace interval on first use.
:param Name keyName: The name of the public key used to sign the interest.
:paramt int timestamp: The timestamp extracted from the interest name.
:param Array<str> failureReason: If verification fails, set
failureReason[0] to the failure reason string.
"""
try:
lastTimestamp = self._keyTimestamps[keyName.toUri()]
except KeyError:
now = Common.getNowMilliseconds()
notBefore = now - self._keyGraceInterval
notAfter = now + self._keyGraceInterval
if not (timestamp > notBefore and timestamp < notAfter):
return False
failureReason[0] = (
"The command interest timestamp is not within the first use grace period of " +
str(self._keyGraceInterval) + " milliseconds.")
else:
return True
else:
if timestamp <= lastTimestamp:
failureReason[0] = (
"The command interest timestamp is not newer than the previous timestamp")
return False
else:
return True
def _updateTimestampForKey(self, keyName, timestamp):
"""
Trim the table size down if necessary, and insert/update the latest
interest signing timestamp for the key.
Any key which has not been used within the TTL period is purged. If the
table is still too large, the oldest key is purged.
:param Name keyName: The name of the public key used to sign the interest.
:paramt int timestamp: The timestamp extracted from the interest name.
"""
self._keyTimestamps[keyName.toUri()] = timestamp
if len(self._keyTimestamps) >= self._maxTrackedKeys:
now = Common.getNowMilliseconds()
oldestTimestamp = now
oldestKey = None
trackedKeys = self._keyTimestamps.keys()
for keyUri in trackedKeys:
ts = self._keyTimestamps[keyUri]
if now - ts > self._keyTimestampTtl:
del self._keyTimestamps[keyUri]
elif ts < oldestTimestamp:
oldestTimestamp = ts
oldestKey = keyUri
if len(self._keyTimestamps) > self._maxTrackedKeys:
# have not removed enough
del self._keyTimestamps[oldestKey]
def checkVerificationPolicy(self, dataOrInterest, stepCount, onVerified,
onValidationFailed, wireFormat = None):
"""
If there is a rule matching the data or interest, and the matching
certificate is missing, download it. If there is no matching rule,
verification fails. Otherwise, verify the signature using the public key
in the IdentityStorage.
:param dataOrInterest: The Data object or interest with the signature to
check.
:type dataOrInterest: Data or Interest
:param int stepCount: The number of verification steps that have been
done, used to track the verification progress.
:param onVerified: If the signature is verified, this calls
onVerified(dataOrInterest).
NOTE: The library will log any exceptions raised by this callback, but
for better error handling the callback should catch and properly
handle any exceptions.
:type onVerified: function object
:param onValidationFailed: If the signature check fails, this calls
onValidationFailed(dataOrInterest, reason).
NOTE: The library will log any exceptions raised by this callback, but
for better error handling the callback should catch and properly
handle any exceptions.
:type onValidationFailed: function object
:return: None for no further step for looking up a certificate chain.
:rtype: ValidationRequest
"""
objectName = dataOrInterest.getName()
matchType = "data"
# For command interests, we need to ignore the last 4 components when
# matching the name.
if isinstance(dataOrInterest, Interest):
objectName = objectName.getPrefix(-4)
matchType = "interest"
signature = self._extractSignature(dataOrInterest, wireFormat)
# no signature -> fail
if signature is None:
try:
onValidationFailed(
dataOrInterest, "Cannot extract the signature from " +
dataOrInterest.getName().toUri())
except:
logging.exception("Error in onValidationFailed")
return None
failureReason = ["unknown"]
certificateInterest = self._getCertificateInterest(
stepCount, matchType, objectName, signature, failureReason)
if certificateInterest is None:
try:
onValidationFailed(dataOrInterest, failureReason[0])
except:
logging.exception("Error in onValidationFailed")
return None
if certificateInterest.getName().size() > 0:
def onCertificateDownloadComplete(data):
if self._isSecurityV1:
try:
certificate = IdentityCertificate(data)
except:
try:
onValidationFailed(
dataOrInterest, "Cannot decode certificate " +
data.getName().toUri())
except:
logging.exception("Error in onValidationFailed")
return None
self._certificateCache.insertCertificate(certificate)
else:
try:
certificate = CertificateV2(data)
except:
try:
onValidationFailed(
dataOrInterest, "Cannot decode certificate " +
data.getName().toUri())
except:
logging.exception("Error in onValidationFailed")
return None
self._certificateCacheV2.insert(certificate)
self.checkVerificationPolicy(dataOrInterest, stepCount+1,
onVerified, onValidationFailed)
return ValidationRequest(certificateInterest,
onCertificateDownloadComplete, onValidationFailed,
2, stepCount+1)
# For interests, we must check that the timestamp is fresh enough.
# This is done after (possibly) downloading the certificate to avoid
# filling the cache with bad keys.
if isinstance(dataOrInterest, Interest):
signatureName = KeyLocator.getFromSignature(signature).getKeyName()
if self._isSecurityV1:
keyName = IdentityCertificate.certificateNameToPublicKeyName(
signatureName)
else:
keyName = signatureName
timestamp = dataOrInterest.getName().get(-4).toNumber()
if not self._interestTimestampIsFresh(
keyName, timestamp, failureReason):
try:
onValidationFailed(dataOrInterest, failureReason[0])
except:
logging.exception("Error in onValidationFailed")
return None
# Certificate is known. Verify the signature.
# wireEncode returns the cached encoding if available.
if self._verify(signature, dataOrInterest.wireEncode(), failureReason):
try:
onVerified(dataOrInterest)
except:
logging.exception("Error in onVerified")
if isinstance(dataOrInterest, Interest):
self._updateTimestampForKey(keyName, timestamp)
else:
try:
onValidationFailed(dataOrInterest, failureReason[0])
except:
logging.exception("Error in onValidationFailed")
def _getCertificateInterest(self, stepCount, matchType, objectName,
signature, failureReason):
"""
This is a helper for checkVerificationPolicy to verify the rule and
return a certificate interest to fetch the next certificate in the
hierarchy if needed.
:param int stepCount: The number of verification steps that have been
done, used to track the verification progress.
:param str matchType: Either "data" or "interest".
:param Name objectName: The name of the data or interest packet.
:param Signature signature: The Signature object for the data or
interest packet.
:param Array<str> failureReason: If can't determine the interest, set
failureReason[0] to the failure reason.
:return: None if can't determine the interest, otherwise the interest
for the ValidationRequest to fetch the next certificate. However, if
the interest has an empty name, the validation succeeded and no need
to fetch a certificate.
:rtype: Interest
"""
if stepCount > self._maxDepth:
failureReason[0] = ("The verification stepCount " + stepCount +
" exceeded the maxDepth " + self._maxDepth)
return None
# First see if we can find a rule to match this packet.
try:
matchedRule = self._findMatchingRule(objectName, matchType)
except:
matchedRule = None
# No matching rule -> fail.
if matchedRule is None:
failureReason[0] = "No matching rule found for " + objectName.toUri()
return None
if not KeyLocator.canGetFromSignature(signature):
# We only support signature types with key locators.
failureReason[0] = "The signature type does not support a KeyLocator"
return None
keyLocator = KeyLocator.getFromSignature(signature)
signatureName = keyLocator.getKeyName()
# No key name in KeyLocator -> fail.
if signatureName.size() == 0:
failureReason[0] = "The signature KeyLocator doesn't have a key name"
return None
signatureMatches = self._checkSignatureMatch(
signatureName, objectName, matchedRule, failureReason)
if not signatureMatches:
return None
# Before we look up keys, refresh any certificate directories.
self._refreshManager.refreshAnchors()
# If we don't actually have the certificate yet, return a
# certificateInterest for it.
if self._isSecurityV1:
foundCert = self._refreshManager.getCertificate(signatureName)
if foundCert is None:
foundCert = self._certificateCache.getCertificate(signatureName)
if foundCert is None:
return Interest(signatureName)
else:
foundCert = self._refreshManager.getCertificateV2(signatureName)
if foundCert is None:
foundCert = self._certificateCacheV2.find(signatureName)
if foundCert is None:
return Interest(signatureName)
return Interest()
def _verify(self, signatureInfo, signedBlob, failureReason):
"""
Check the type of signatureInfo to get the KeyLocator. Look in the
IdentityStorage for the public key with the name in the KeyLocator and
use it to verify the signedBlob. If the public key can't be found,
return false. (This is a generalized method which can verify both a Data
packet and an interest.)
:param Signature signatureInfo: An object of a subclass of Signature,
e.g. Sha256WithRsaSignature.
:param SignedBlob signedBlob: the SignedBlob with the signed portion to
verify.
:param Array<str> failureReason: If verification fails, set
failureReason[0] to the failure reason string.
:return: True if the signature verifies, False if not.
:rtype: boolean
"""
# We have already checked once that there is a key locator.
keyLocator = KeyLocator.getFromSignature(signatureInfo)
if (keyLocator.getType() == KeyLocatorType.KEYNAME):
# Assume the key name is a certificate name.
signatureName = keyLocator.getKeyName()
if self._isSecurityV1:
certificate = self._refreshManager.getCertificate(signatureName)
if certificate is None:
certificate = self._certificateCache.getCertificate(
signatureName)
if certificate is None:
failureReason[0] = ("Cannot find a certificate with name " +
signatureName.toUri())
return False
publicKeyDer = certificate.getPublicKeyInfo().getKeyDer()
if publicKeyDer.isNull():
# We don't expect this to happen.
failureReason[0] = (
"There is no public key in the certificate with name " +
certificate.getName().toUri())
return False
else:
certificate = self._refreshManager.getCertificateV2(signatureName)
if certificate is None:
certificate = self._certificateCacheV2.find(
signatureName)
if certificate is None:
failureReason[0] = ("Cannot find a certificate with name " +
signatureName.toUri())
return False
try:
publicKeyDer = certificate.getPublicKey()
except:
# We don't expect this to happen.
failureReason[0] = (
"There is no public key in the certificate with name " +
certificate.getName().toUri())
return False
if self.verifySignature(signatureInfo, signedBlob, publicKeyDer):
return True
else:
failureReason[0] = (
"The signature did not verify with the given public key")
return False
else:
failureReason[0] = "The KeyLocator does not have a key name"
return False
