tlslite/handshakesettings.py
# Authors:
# Trevor Perrin
# Dave Baggett (Arcode Corporation) - cleanup handling of constants
# Yngve Pettersen (ported by Paul Sokolovsky) - TLS 1.2
#
# See the LICENSE file for legal information regarding use of this file.
"""Class for setting handshake parameters."""
from .constants import CertificateType
from .utils import cryptomath
from .utils import cipherfactory
from .utils.compat import ecdsaAllCurves, int_types, ML_KEM_AVAILABLE
from .utils.compression import compression_algo_impls
CIPHER_NAMES = ["chacha20-poly1305",
"aes256gcm", "aes128gcm",
"aes256ccm", "aes128ccm",
"aes256", "aes128",
"3des"]
ALL_CIPHER_NAMES = CIPHER_NAMES + ["chacha20-poly1305_draft00",
"aes128ccm_8", "aes256ccm_8",
"rc4", "null"]
# Don't allow "md5" by default
MAC_NAMES = ["sha", "sha256", "sha384", "aead"]
ALL_MAC_NAMES = MAC_NAMES + ["md5"]
KEY_EXCHANGE_NAMES = ["ecdhe_ecdsa", "rsa", "dhe_rsa", "ecdhe_rsa", "srp_sha",
"srp_sha_rsa", "ecdh_anon", "dh_anon", "dhe_dsa"]
CIPHER_IMPLEMENTATIONS = ["openssl", "pycrypto", "python"]
CERTIFICATE_TYPES = ["x509"]
RSA_SIGNATURE_HASHES = ["sha512", "sha384", "sha256", "sha224", "sha1"]
DSA_SIGNATURE_HASHES = ["sha512", "sha384", "sha256", "sha224", "sha1"]
ECDSA_SIGNATURE_HASHES = ["sha512", "sha384", "sha256", "sha224", "sha1"]
ALL_RSA_SIGNATURE_HASHES = RSA_SIGNATURE_HASHES + ["md5"]
SIGNATURE_SCHEMES = ["Ed25519", "Ed448"]
RSA_SCHEMES = ["pss", "pkcs1"]
CURVE_NAMES = []
if ML_KEM_AVAILABLE:
CURVE_NAMES += ["secp256r1mlkem768", "x25519mlkem768",
"secp384r1mlkem1024"]
# while secp521r1 is the most secure, it's also much slower than the others
# so place it as the last one
CURVE_NAMES += ["x25519", "x448", "secp384r1", "secp256r1",
"secp521r1"]
ALL_CURVE_NAMES = CURVE_NAMES + ["secp256k1", "brainpoolP512r1",
"brainpoolP384r1", "brainpoolP256r1"]
if ecdsaAllCurves:
ALL_CURVE_NAMES += ["secp224r1", "secp192r1"]
ALL_DH_GROUP_NAMES = ["ffdhe2048", "ffdhe3072", "ffdhe4096", "ffdhe6144",
"ffdhe8192"]
CURVE_ALIASES = {"secp256r1": ('NIST256p', 'prime256v1', 'P-256'),
"secp384r1": ('NIST384p', 'P-384'),
"secp521r1": ('NIST521p', 'P-521'),
"secp256k1": ('SECP256k1',),
"secp192r1": ('NIST192p', 'P-192'),
"secp224r1": ('NIST224p', 'P-224'),
"brainpoolP256r1": ('BRAINPOOLP256r1',),
"brainpoolP384r1": ('BRAINPOOLP384r1',),
"brainpoolP512r1": ('BRAINPOOLP512r1',)}
# list of supported groups in TLS 1.3 as per RFC 8446, chapter 4.2.7. (excluding private use here)
TLS13_PERMITTED_GROUPS = ["secp256r1", "secp384r1", "secp521r1",
"x25519", "x448", "ffdhe2048",
"ffdhe3072", "ffdhe4096", "ffdhe6144",
"ffdhe8192", "secp256r1mlkem768", "x25519mlkem768",
"secp384r1mlkem1024"]
KNOWN_VERSIONS = ((3, 0), (3, 1), (3, 2), (3, 3), (3, 4))
TICKET_CIPHERS = ["chacha20-poly1305", "aes256gcm", "aes128gcm", "aes128ccm",
"aes128ccm_8", "aes256ccm", "aes256ccm_8"]
PSK_MODES = ["psk_dhe_ke", "psk_ke"]
ALL_COMPRESSION_ALGOS_SEND = ["zlib"]
if compression_algo_impls["brotli_compress"]:
ALL_COMPRESSION_ALGOS_SEND.append('brotli')
if compression_algo_impls["zstd_compress"]:
ALL_COMPRESSION_ALGOS_SEND.append('zstd')
ALL_COMPRESSION_ALGOS_RECEIVE = ["zlib"]
if compression_algo_impls["brotli_decompress"]:
ALL_COMPRESSION_ALGOS_RECEIVE.append('brotli')
if compression_algo_impls["zstd_decompress"]:
ALL_COMPRESSION_ALGOS_RECEIVE.append('zstd')
class Keypair(object):
"""
Key, certificate and related data.
Stores also certificate associate data like OCSPs and transparency info.
TODO: add the above
First certificate in certificates needs to match key, remaining should
build a trust path to a root CA.
:vartype key: RSAKey or ECDSAKey
:ivar key: private key
:vartype certificates: list(X509)
:ivar certificates: the certificates to send to peer if the key is selected
for use. The first one MUST include the public key of the ``key``
"""
def __init__(self, key=None, certificates=tuple()):
self.key = key
self.certificates = certificates
def validate(self):
"""Sanity check the keypair."""
if not self.key or not self.certificates:
raise ValueError("Key or certificate missing in Keypair")
class VirtualHost(object):
"""
Configuration of keys and certs for a single virual server.
This class encapsulates keys and certificates for hosts specified by
server_name (SNI) and ALPN extensions.
TODO: support SRP as alternative to certificates
TODO: support PSK as alternative to certificates
:vartype keys: list(Keypair)
:ivar keys: List of certificates and keys to be used in this
virtual host. First keypair able to server ClientHello will be used.
:vartype hostnames: set(bytes)
:ivar hostnames: all the hostnames that server supports
please use :py:meth:`matches_hostname` to verify if the VirtualHost
can serve a request to a given hostname as that allows wildcard hosts
that always reply True.
:vartype trust_anchors: list(X509)
:ivar trust_anchors: list of CA certificates supported for client
certificate authentication, sent in CertificateRequest
:ivar list(bytes) app_protocols: all the application protocols that the
server supports (for ALPN)
"""
def __init__(self):
"""Set up default configuration."""
self.keys = []
self.hostnames = set()
self.trust_anchors = []
self.app_protocols = []
def matches_hostname(self, hostname):
"""Checks if the virtual host can serve hostname"""
return hostname in self.hostnames
def validate(self):
"""Sanity check the settings"""
if not self.keys:
raise ValueError("Virtual host missing keys")
for i in self.keys:
i.validate()
class HandshakeSettings(object):
"""
This class encapsulates various parameters that can be used with
a TLS handshake.
:vartype minKeySize: int
:ivar minKeySize: The minimum bit length for asymmetric keys.
If the other party tries to use SRP, RSA, DSA, or Diffie-Hellman
parameters smaller than this length, an alert will be
signalled. The default is 1023.
:vartype maxKeySize: int
:ivar maxKeySize: The maximum bit length for asymmetric keys.
If the other party tries to use SRP, RSA, DSA, or Diffie-Hellman
parameters larger than this length, an alert will be signalled.
The default is 8193.
:vartype cipherNames: list(str)
:ivar cipherNames: The allowed ciphers.
The allowed values in this list are 'chacha20-poly1305', 'aes256gcm',
'aes128gcm', 'aes256', 'aes128', '3des', 'chacha20-poly1305_draft00',
'null' and
'rc4'. If these settings are used with a client handshake, they
determine the order of the ciphersuites offered in the ClientHello
message.
If these settings are used with a server handshake, the server will
choose whichever ciphersuite matches the earliest entry in this
list.
The default value is list that excludes 'rc4', 'null' and
'chacha20-poly1305_draft00'.
:vartype macNames: list(str)
:ivar macNames: The allowed MAC algorithms.
The allowed values in this list are 'sha384', 'sha256', 'aead', 'sha'
and 'md5'.
The default value is list that excludes 'md5'.
:vartype certificateTypes: list(str)
:ivar certificateTypes: The allowed certificate types.
The only allowed certificate type is 'x509'. This list is only used
with a
client handshake. The client will advertise to the server which
certificate
types are supported, and will check that the server uses one of the
appropriate types.
:vartype minVersion: tuple
:ivar minVersion: The minimum allowed SSL/TLS version.
This variable can be set to (3, 0) for SSL 3.0, (3, 1) for TLS 1.0,
(3, 2) for
TLS 1.1, or (3, 3) for TLS 1.2. If the other party wishes to use a
lower
version, a protocol_version alert will be signalled. The default is
(3, 1).
:vartype maxVersion: tuple
:ivar maxVersion: The maximum allowed SSL/TLS version.
This variable can be set to (3, 0) for SSL 3.0, (3, 1) for TLS 1.0,
(3, 2) for TLS 1.1, or (3, 3) for TLS 1.2. If the other party wishes
to use a
higher version, a protocol_version alert will be signalled. The
default is (3, 3).
.. warning:: Some servers may (improperly) reject clients which offer
support
for TLS 1.1 or higher. In this case, try lowering maxVersion to
(3, 1).
:vartype useExperimentalTackExtension: bool
:ivar useExperimentalTackExtension: Whether to enabled TACK support.
Note that TACK support is not standardized by IETF and uses a temporary
TLS Extension number, so should NOT be used in production software.
:vartype sendFallbackSCSV: bool
:ivar sendFallbackSCSV: Whether to, as a client, send FALLBACK_SCSV.
:vartype rsaSigHashes: list(str)
:ivar rsaSigHashes: List of hashes supported (and advertised as such) for
TLS 1.2 signatures over Server Key Exchange or Certificate Verify with
RSA signature algorithm.
The list is sorted from most wanted to least wanted algorithm.
The allowed hashes are: "md5", "sha1", "sha224", "sha256",
"sha384" and "sha512". The default list does not include md5.
:vartype dsaSigHashes: list(str)
:ivar dsaSigHashes: List of hashes supported (and advertised as such) for
TLS 1.2 signatures over Server Key Exchange or Certificate Verify with
DSA signature algorithm.
The list is sorted from most wanted to least wanted algorithm.
The allowed hashes are: "sha1", "sha224", "sha256",
"sha384" and "sha512".
:vartype ecdsaSigHashes: list(str)
:ivar ecdsaSigHashes: List of hashes supported (and advertised as such) for
TLS 1.2 signatures over Server Key Exchange or Certificate Verify with
ECDSA signature algorithm.
The list is sorted from most wanted to least wanted algorithm.
The allowed hashes are: "sha1", "sha224", "sha256",
"sha384" and "sha512".
:vartype more_sig_schemes: list(str)
:ivar more_sig_schemes: List of additional signatures schemes (ones
that don't use RSA-PKCS#1 v1.5, RSA-PSS, DSA, or ECDSA) to advertise
as supported.
Currently supported are: "Ed25519", and "Ed448".
:vartype eccCurves: list(str)
:ivar eccCurves: List of named curves that are to be advertised as
supported in supported_groups extension.
:vartype useEncryptThenMAC: bool
:ivar useEncryptThenMAC: whether to support the encrypt then MAC extension
from RFC 7366. True by default.
:vartype useExtendedMasterSecret: bool
:ivar useExtendedMasterSecret: whether to support the extended master
secret calculation from RFC 7627. True by default.
:vartype requireExtendedMasterSecret: bool
:ivar requireExtendedMasterSecret: whether to require negotiation of
extended master secret calculation for successful connection. Requires
useExtendedMasterSecret to be set to true. False by default.
:vartype defaultCurve: str
:ivar defaultCurve: curve that will be used by server in case the client
did not advertise support for any curves. It does not have to be the
first curve for eccCurves and may be distinct from curves from that
list.
:vartype keyShares: list(str)
:ivar keyShares: list of TLS 1.3 key shares to include in Client Hello
:vartype padding_cb: func
:ivar padding_cb: Callback to function computing number of padding bytes
for TLS 1.3. Signature is cb_func(msg_size, content_type, max_size).
:vartype pskConfigs: list(tuple(bytearray, bytearray, bytearray))
:ivar pskConfigs: list of tuples, first element of the tuple is the
human readable, UTF-8 encoded, "identity" of the associated secret
(bytearray, can be empty for TLS 1.2 and earlier), second element is
the binary secret (bytearray), third is an optional parameter
specifying the PRF hash to be used in TLS 1.3 (``sha256`` or
``sha384``, with ``sha256`` being the default)
:vartype ticketKeys: list(bytearray)
:ivar ticketKeys: keys to be used for encrypting and decrypting session
tickets. First entry is the encryption key for new tickets and the
default decryption key, subsequent entries are the fallback keys
allowing for key rollover. The keys need to be of size appropriate
for a selected cipher in ticketCipher, 32 bytes for 'aes256gcm' and
'chacha20-poly1305', 16 bytes for 'aes128-gcm'.
New keys should be generated regularly and replace old ones. Key use
time should generally not be longer than 24h and key life-time should
not be longer than 48h.
Leave empty to disable session ticket support on server side.
:vartype ticketCipher: str
:ivar ticketCipher: name of the cipher used for encrypting the session
tickets. 'aes256gcm' by default, 'aes128gcm' or 'chacha20-poly1305'
alternatively.
:vartype ticketLifetime: int
:ivar ticketLifetime: maximum allowed lifetime of ticket encryption key,
in seconds. 1 day by default
:vartype ticket_count: int
:ivar ticket_count: number of tickets the server will send to the client
after establishing the connection in TLS 1.3. If a positive integer,
it enabled support for ticket based resumption in TLS 1.2 and earlier.
:vartype psk_modes: list(str)
:ivar psk_modes: acceptable modes for the PSK key exchange in TLS 1.3
:ivar int max_early_data: maximum number of bytes acceptable for 0-RTT
early_data processing. In other words, how many bytes will the server
try to process, but ignore, in case the Client Hello includes
early_data extension.
:vartype use_heartbeat_extension: bool
:ivar use_heartbeat_extension: whether to support heartbeat extension from
RFC 6520. True by default.
:vartype heartbeat_response_callback: func
:ivar heartbeat_response_callback: Callback to function when Heartbeat
response is received.
:vartype ~.record_size_limit: int
:ivar ~.record_size_limit: maximum size of records we are willing to process
(value advertised to the other side). It must not be larger than
2**14+1 (the maximum for TLS 1.3) and will be reduced to 2**14 if TLS
1.2 or lower is the highest enabled version. Must not be set to values
smaller than 64. Set to None to disable support for the extension.
See also: RFC 8449.
:vartype keyExchangeNames: list
:ivar keyExchangeNames: Enabled key exchange types for the connection,
influences selected cipher suites.
:vartype certificate_compression_send: list(str)
:ivar certificate_compression_send: a list of compression algorithms that
will be used to compress the certificate if compress_cerificate(27)
extension is supported in the handshake. This option is for when a
certificate was send/compressed by this peer.
:vartype certificate_compression_receive: list(str)
:ivar certificate_compression_receive: a list of compression algorithms
that will be used to compress the certificate if
compress_cerificate(27) extension is supported in the handshake. This
option is for when a certificate was received/decompressed by this
peer.
"""
def _init_key_settings(self):
"""Create default variables for key-related settings."""
self.minKeySize = 1023
self.maxKeySize = 8193
self.rsaSigHashes = list(RSA_SIGNATURE_HASHES)
self.rsaSchemes = list(RSA_SCHEMES)
self.dsaSigHashes = list(DSA_SIGNATURE_HASHES)
self.virtual_hosts = []
# DH key settings
self.eccCurves = list(CURVE_NAMES)
self.dhParams = None
self.dhGroups = list(ALL_DH_GROUP_NAMES)
self.defaultCurve = "secp256r1"
if ML_KEM_AVAILABLE:
self.keyShares = ["x25519mlkem768"]
else:
self.keyShares = []
self.keyShares += ["secp256r1", "x25519"]
self.padding_cb = None
self.use_heartbeat_extension = True
self.heartbeat_response_callback = None
def _init_misc_extensions(self):
"""Default variables for assorted extensions."""
self.certificateTypes = list(CERTIFICATE_TYPES)
self.useExperimentalTackExtension = False
self.sendFallbackSCSV = False
self.useEncryptThenMAC = True
self.ecdsaSigHashes = list(ECDSA_SIGNATURE_HASHES)
self.more_sig_schemes = list(SIGNATURE_SCHEMES)
self.usePaddingExtension = True
self.useExtendedMasterSecret = True
self.requireExtendedMasterSecret = False
# PSKs
self.pskConfigs = []
self.psk_modes = list(PSK_MODES)
# session tickets
self.ticketKeys = []
self.ticketCipher = "aes256gcm"
self.ticketLifetime = 24 * 60 * 60
self.max_early_data = 2 ** 14 + 16 # full record + tag
# send two tickets so that client can quickly ramp up number of
# resumed connections (as tickets are single-use in TLS 1.3
self.ticket_count = 2
self.record_size_limit = 2**14 + 1 # TLS 1.3 includes content type
# Certificate compression
self.certificate_compression_send = list(ALL_COMPRESSION_ALGOS_SEND)
self.certificate_compression_receive = \
list(ALL_COMPRESSION_ALGOS_RECEIVE)
def __init__(self):
"""Initialise default values for settings."""
self._init_key_settings()
self._init_misc_extensions()
self.minVersion = (3, 1)
self.maxVersion = (3, 4)
self.versions = [(3, 4), (3, 3), (3, 2), (3, 1)]
self.cipherNames = list(CIPHER_NAMES)
self.macNames = list(MAC_NAMES)
self.keyExchangeNames = list(KEY_EXCHANGE_NAMES)
self.cipherImplementations = list(CIPHER_IMPLEMENTATIONS)
@staticmethod
def _sanityCheckKeySizes(other):
"""Check if key size limits are sane"""
if other.minKeySize < 512:
raise ValueError("minKeySize too small")
if other.minKeySize > 16384:
raise ValueError("minKeySize too large")
if other.maxKeySize < 512:
raise ValueError("maxKeySize too small")
if other.maxKeySize > 16384:
raise ValueError("maxKeySize too large")
if other.maxKeySize < other.minKeySize:
raise ValueError("maxKeySize smaller than minKeySize")
# check also keys of virtual hosts
for i in other.virtual_hosts:
i.validate()
@staticmethod
def _not_matching(values, sieve):
"""Return list of items from values that are not in sieve."""
return [val for val in values if val not in sieve]
@staticmethod
def _sanityCheckCipherSettings(other):
"""Check if specified cipher settings are known."""
not_matching = HandshakeSettings._not_matching
unknownCiph = not_matching(other.cipherNames, ALL_CIPHER_NAMES)
if unknownCiph:
raise ValueError("Unknown cipher name: {0}".format(unknownCiph))
unknownMac = not_matching(other.macNames, ALL_MAC_NAMES)
if unknownMac:
raise ValueError("Unknown MAC name: {0}".format(unknownMac))
unknownKex = not_matching(other.keyExchangeNames, KEY_EXCHANGE_NAMES)
if unknownKex:
raise ValueError("Unknown key exchange name: {0}"
.format(unknownKex))
unknownImpl = not_matching(other.cipherImplementations,
CIPHER_IMPLEMENTATIONS)
if unknownImpl:
raise ValueError("Unknown cipher implementation: {0}"
.format(unknownImpl))
@staticmethod
def _sanityCheckECDHSettings(other):
"""Check ECDHE settings if they are sane."""
not_matching = HandshakeSettings._not_matching
unknownCurve = not_matching(other.eccCurves, ALL_CURVE_NAMES)
if unknownCurve:
raise ValueError("Unknown ECC Curve name: {0}"
.format(unknownCurve))
if other.defaultCurve not in ALL_CURVE_NAMES:
raise ValueError("Unknown default ECC Curve name: {0}"
.format(other.defaultCurve))
nonAdvertisedGroup = [val for val in other.keyShares
if val not in other.eccCurves and
val not in other.dhGroups]
if nonAdvertisedGroup:
raise ValueError("Key shares for not enabled groups specified: {0}"
.format(nonAdvertisedGroup))
unknownSigHash = not_matching(other.ecdsaSigHashes,
ECDSA_SIGNATURE_HASHES)
if unknownSigHash:
raise ValueError("Unknown ECDSA signature hash: '{0}'".\
format(unknownSigHash))
unknownSigHash = not_matching(other.more_sig_schemes,
SIGNATURE_SCHEMES)
if unknownSigHash:
raise ValueError("Unkonwn more_sig_schemes specified: '{0}'"
.format(unknownSigHash))
unknownDHGroup = not_matching(other.dhGroups, ALL_DH_GROUP_NAMES)
if unknownDHGroup:
raise ValueError("Unknown FFDHE group name: '{0}'"
.format(unknownDHGroup))
# TLS 1.3 limits the allowed groups (RFC 8446,ch. 4.2.7.)
if other.maxVersion == (3, 4):
forbiddenGroup = HandshakeSettings._not_matching(other.eccCurves, TLS13_PERMITTED_GROUPS)
if forbiddenGroup:
raise ValueError("The following enabled groups are forbidden in TLS 1.3: {0}"
.format(forbiddenGroup))
@staticmethod
def _sanityCheckDHSettings(other):
"""Check if (EC)DHE settings are sane."""
not_matching = HandshakeSettings._not_matching
HandshakeSettings._sanityCheckECDHSettings(other)
unknownKeyShare = [val for val in other.keyShares
if val not in ALL_DH_GROUP_NAMES and
val not in ALL_CURVE_NAMES]
if unknownKeyShare:
raise ValueError("Unknown key share: '{0}'"
.format(unknownKeyShare))
if other.dhParams and (len(other.dhParams) != 2 or
not isinstance(other.dhParams[0], int_types) or
not isinstance(other.dhParams[1], int_types)):
raise ValueError("DH parameters need to be a tuple of integers")
@staticmethod
def _sanityCheckPrimitivesNames(other):
"""Check if specified cryptographic primitive names are known"""
HandshakeSettings._sanityCheckCipherSettings(other)
HandshakeSettings._sanityCheckDHSettings(other)
not_matching = HandshakeSettings._not_matching
unknownType = not_matching(other.certificateTypes, CERTIFICATE_TYPES)
if unknownType:
raise ValueError("Unknown certificate type: {0}"
.format(unknownType))
unknownSigHash = not_matching(other.rsaSigHashes,
ALL_RSA_SIGNATURE_HASHES)
if unknownSigHash:
raise ValueError("Unknown RSA signature hash: '{0}'"
.format(unknownSigHash))
unknownRSAPad = not_matching(other.rsaSchemes, RSA_SCHEMES)
if unknownRSAPad:
raise ValueError("Unknown RSA padding mode: '{0}'"
.format(unknownRSAPad))
unknownSigHash = not_matching(other.dsaSigHashes,
DSA_SIGNATURE_HASHES)
if unknownSigHash:
raise ValueError("Unknown DSA signature hash: '{0}'"
.format(unknownSigHash))
if not other.rsaSigHashes and not other.ecdsaSigHashes and \
not other.dsaSigHashes and not other.more_sig_schemes and \
other.maxVersion >= (3, 3):
raise ValueError("TLS 1.2 requires signature algorithms to be set")
@staticmethod
def _sanityCheckProtocolVersions(other):
"""Check if set protocol version are sane"""
if other.minVersion > other.maxVersion:
raise ValueError("Versions set incorrectly")
if other.minVersion not in KNOWN_VERSIONS:
raise ValueError("minVersion set incorrectly")
if other.maxVersion not in KNOWN_VERSIONS:
raise ValueError("maxVersion set incorrectly")
if other.maxVersion < (3, 4):
other.versions = [i for i in other.versions if i < (3, 4)]
@staticmethod
def _sanityCheckEMSExtension(other):
"""Check if settings for EMS are sane."""
if other.useExtendedMasterSecret not in (True, False):
raise ValueError("useExtendedMasterSecret must be True or False")
if other.requireExtendedMasterSecret not in (True, False):
raise ValueError("requireExtendedMasterSecret must be True "
"or False")
if other.requireExtendedMasterSecret and \
not other.useExtendedMasterSecret:
raise ValueError("requireExtendedMasterSecret requires "
"useExtendedMasterSecret")
@staticmethod
def _sanityCheckExtensions(other):
"""Check if set extension settings are sane"""
not_matching = HandshakeSettings._not_matching
if other.useEncryptThenMAC not in (True, False):
raise ValueError("useEncryptThenMAC can only be True or False")
if other.usePaddingExtension not in (True, False):
raise ValueError("usePaddingExtension must be True or False")
if other.use_heartbeat_extension not in (True, False):
raise ValueError("use_heartbeat_extension must be True or False")
if other.heartbeat_response_callback and not other.use_heartbeat_extension:
raise ValueError("heartbeat_response_callback requires "
"use_heartbeat_extension")
if other.record_size_limit is not None and \
not 64 <= other.record_size_limit <= 2**14 + 1:
raise ValueError("record_size_limit cannot exceed 2**14+1 bytes")
HandshakeSettings._sanityCheckEMSExtension(other)
if other.certificate_compression_send:
try:
unknownAlgos = not_matching(
other.certificate_compression_send,
ALL_COMPRESSION_ALGOS_SEND)
except TypeError:
raise ValueError("certificate_compression must be an iterable "
"of strings")
if unknownAlgos:
raise ValueError("Unknown compression algorithm: '{0}'"
.format(unknownAlgos))
if other.certificate_compression_receive:
try:
unknownAlgos = not_matching(
other.certificate_compression_receive,
ALL_COMPRESSION_ALGOS_RECEIVE)
except TypeError:
raise ValueError("certificate_compression must be an iterable "
"of strings")
if unknownAlgos:
raise ValueError("Unknown compression algorithm: '{0}'"
.format(unknownAlgos))
@staticmethod
def _not_allowed_len(values, sieve):
"""Return True if length of any item in values is not in sieve."""
sieve = set(sieve)
return any(len(i) not in sieve for i in values)
@staticmethod
def _sanityCheckPsks(other):
"""Check if the set PSKs are sane."""
if HandshakeSettings._not_allowed_len(other.pskConfigs, [2, 3]):
raise ValueError("pskConfigs items must be a 2 or 3-element"
"tuples")
badHashes = [i[2] for i in other.pskConfigs if
len(i) == 3 and i[2] not in set(['sha256', 'sha384'])]
if badHashes:
raise ValueError("pskConfigs include invalid hash specifications: "
"{0}".format(badHashes))
bad_psk_modes = [i for i in other.psk_modes if
i not in PSK_MODES]
if bad_psk_modes:
raise ValueError("psk_modes includes invalid key exchange modes: "
"{0}".format(bad_psk_modes))
@staticmethod
def _sanityCheckTicketSettings(other):
"""Check if the session ticket settings are sane."""
if other.ticketCipher not in TICKET_CIPHERS:
raise ValueError("Invalid cipher for session ticket encryption: "
"{0}".format(other.ticketCipher))
if HandshakeSettings._not_allowed_len(other.ticketKeys, [16, 32]):
raise ValueError("Session ticket encryption keys must be 16 or 32"
"bytes long")
if not 0 < other.ticketLifetime <= 7 * 24 * 60 * 60:
raise ValueError("Ticket lifetime must be a positive integer "
"smaller or equal 604800 (7 days)")
# while not ticket setting per-se, it is related to session tickets
if not 0 < other.max_early_data <= 2**64:
raise ValueError("max_early_data must be between 0 and 2GiB")
if not 0 <= other.ticket_count < 2**16:
raise ValueError("Incorrect amount for number of new session "
"tickets to send")
def _copy_cipher_settings(self, other):
"""Copy values related to cipher selection."""
other.cipherNames = self.cipherNames
other.macNames = self.macNames
other.keyExchangeNames = self.keyExchangeNames
other.cipherImplementations = self.cipherImplementations
other.minVersion = self.minVersion
other.maxVersion = self.maxVersion
other.versions = self.versions
def _copy_extension_settings(self, other):
"""Copy values of settings related to extensions."""
other.useExtendedMasterSecret = self.useExtendedMasterSecret
other.requireExtendedMasterSecret = self.requireExtendedMasterSecret
other.useExperimentalTackExtension = self.useExperimentalTackExtension
other.sendFallbackSCSV = self.sendFallbackSCSV
other.useEncryptThenMAC = self.useEncryptThenMAC
other.usePaddingExtension = self.usePaddingExtension
# session tickets
other.padding_cb = self.padding_cb
other.ticketKeys = self.ticketKeys
other.ticketCipher = self.ticketCipher
other.ticketLifetime = self.ticketLifetime
other.max_early_data = self.max_early_data
other.ticket_count = self.ticket_count
other.record_size_limit = self.record_size_limit
other.certificate_compression_send = self.certificate_compression_send
other.certificate_compression_receive = \
self.certificate_compression_receive
@staticmethod
def _remove_all_matches(values, needle):
"""Remove all instances of needle from values."""
values[:] = (i for i in values if i != needle)
def _sanity_check_ciphers(self, other):
"""Remove unsupported ciphers in current configuration."""
if not cipherfactory.tripleDESPresent:
other.cipherNames = other.cipherNames[:]
self._remove_all_matches(other.cipherNames, "3des")
if not other.cipherNames:
raise ValueError("No supported ciphers")
def _sanity_check_implementations(self, other):
"""Remove all backends that are not loaded."""
if not cryptomath.m2cryptoLoaded:
self._remove_all_matches(other.cipherImplementations, "openssl")
if not cryptomath.pycryptoLoaded:
self._remove_all_matches(other.cipherImplementations, "pycrypto")
if not other.cipherImplementations:
raise ValueError("No supported cipher implementations")
def _copy_key_settings(self, other):
"""Copy key-related settings."""
other.minKeySize = self.minKeySize
other.maxKeySize = self.maxKeySize
other.certificateTypes = self.certificateTypes
other.rsaSigHashes = self.rsaSigHashes
other.rsaSchemes = self.rsaSchemes
other.dsaSigHashes = self.dsaSigHashes
other.ecdsaSigHashes = self.ecdsaSigHashes
other.more_sig_schemes = self.more_sig_schemes
other.virtual_hosts = self.virtual_hosts
# DH key params
other.eccCurves = self.eccCurves
other.dhParams = self.dhParams
other.dhGroups = self.dhGroups
other.defaultCurve = self.defaultCurve
other.keyShares = self.keyShares
other.use_heartbeat_extension = self.use_heartbeat_extension
other.heartbeat_response_callback = self.heartbeat_response_callback
def validate(self):
"""
Validate the settings, filter out unsupported ciphersuites and return
a copy of object. Does not modify the original object.
:rtype: HandshakeSettings
:returns: a self-consistent copy of settings
:raises ValueError: when settings are invalid, insecure or unsupported.
"""
other = HandshakeSettings()
self._copy_cipher_settings(other)
self._copy_extension_settings(other)
self._copy_key_settings(other)
other.pskConfigs = self.pskConfigs
other.psk_modes = self.psk_modes
if not other.certificateTypes:
raise ValueError("No supported certificate types")
self._sanityCheckKeySizes(other)
self._sanityCheckPrimitivesNames(other)
self._sanityCheckProtocolVersions(other)
self._sanityCheckExtensions(other)
if other.maxVersion < (3, 3):
# No sha-2 and AEAD pre TLS 1.2
other.macNames = [e for e in self.macNames if
e == "sha" or e == "md5"]
self._sanityCheckPsks(other)
self._sanityCheckTicketSettings(other)
self._sanity_check_implementations(other)
self._sanity_check_ciphers(other)
return other
def getCertificateTypes(self):
"""Get list of certificate types as IDs"""
ret = []
for ct in self.certificateTypes:
if ct == "x509":
ret.append(CertificateType.x509)
else:
raise AssertionError()
return ret