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Diffstat (limited to 'libmproxy/contrib/tls/_constructs.py')
| -rw-r--r-- | libmproxy/contrib/tls/_constructs.py | 213 |
1 files changed, 213 insertions, 0 deletions
diff --git a/libmproxy/contrib/tls/_constructs.py b/libmproxy/contrib/tls/_constructs.py new file mode 100644 index 00000000..49661efb --- /dev/null +++ b/libmproxy/contrib/tls/_constructs.py @@ -0,0 +1,213 @@ +# This file is dual licensed under the terms of the Apache License, Version +# 2.0, and the BSD License. See the LICENSE file in the root of this repository +# for complete details. + +from __future__ import absolute_import, division, print_function + +from construct import Array, Bytes, Struct, UBInt16, UBInt32, UBInt8, PascalString, Embed, \ + TunnelAdapter, GreedyRange, Switch + +from .utils import UBInt24 + +ProtocolVersion = Struct( + "version", + UBInt8("major"), + UBInt8("minor"), +) + +TLSPlaintext = Struct( + "TLSPlaintext", + UBInt8("type"), + ProtocolVersion, + UBInt16("length"), # TODO: Reject packets with length > 2 ** 14 + Bytes("fragment", lambda ctx: ctx.length), +) + +TLSCompressed = Struct( + "TLSCompressed", + UBInt8("type"), + ProtocolVersion, + UBInt16("length"), # TODO: Reject packets with length > 2 ** 14 + 1024 + Bytes("fragment", lambda ctx: ctx.length), +) + +TLSCiphertext = Struct( + "TLSCiphertext", + UBInt8("type"), + ProtocolVersion, + UBInt16("length"), # TODO: Reject packets with length > 2 ** 14 + 2048 + Bytes("fragment", lambda ctx: ctx.length), +) + +Random = Struct( + "random", + UBInt32("gmt_unix_time"), + Bytes("random_bytes", 28), +) + +SessionID = Struct( + "session_id", + UBInt8("length"), + Bytes("session_id", lambda ctx: ctx.length), +) + +CipherSuites = Struct( + "cipher_suites", + UBInt16("length"), # TODO: Reject packets of length 0 + Array(lambda ctx: ctx.length // 2, UBInt16("cipher_suites")), +) + +CompressionMethods = Struct( + "compression_methods", + UBInt8("length"), # TODO: Reject packets of length 0 + Array(lambda ctx: ctx.length, UBInt8("compression_methods")), +) + +ServerName = Struct( + "", + UBInt8("type"), + PascalString("name", length_field=UBInt16("length")), +) + +SNIExtension = Struct( + "", + TunnelAdapter( + PascalString("server_names", length_field=UBInt16("length")), + TunnelAdapter( + PascalString("", length_field=UBInt16("length")), + GreedyRange(ServerName) + ), + ), +) + +ALPNExtension = Struct( + "", + TunnelAdapter( + PascalString("alpn_protocols", length_field=UBInt16("length")), + TunnelAdapter( + PascalString("", length_field=UBInt16("length")), + GreedyRange(PascalString("name")) + ), + ), +) + +UnknownExtension = Struct( + "", + PascalString("bytes", length_field=UBInt16("extensions_length")) +) + +Extension = Struct( + "Extension", + UBInt16("type"), + Embed( + Switch( + "data", lambda ctx: ctx.type, + { + 0x00: SNIExtension, + 0x10: ALPNExtension + }, + default=UnknownExtension + ) + ) +) + +extensions = TunnelAdapter( + PascalString("extensions", length_field=UBInt16("extensions_length")), + GreedyRange(Extension) +) + +ClientHello = Struct( + "ClientHello", + ProtocolVersion, + Random, + SessionID, + CipherSuites, + CompressionMethods, + extensions, +) + +ServerHello = Struct( + "ServerHello", + ProtocolVersion, + Random, + SessionID, + Bytes("cipher_suite", 2), + UBInt8("compression_method"), + extensions, +) + +ClientCertificateType = Struct( + "certificate_types", + UBInt8("length"), # TODO: Reject packets of length 0 + Array(lambda ctx: ctx.length, UBInt8("certificate_types")), +) + +SignatureAndHashAlgorithm = Struct( + "algorithms", + UBInt8("hash"), + UBInt8("signature"), +) + +SupportedSignatureAlgorithms = Struct( + "supported_signature_algorithms", + UBInt16("supported_signature_algorithms_length"), + # TODO: Reject packets of length 0 + Array( + lambda ctx: ctx.supported_signature_algorithms_length / 2, + SignatureAndHashAlgorithm, + ), +) + +DistinguishedName = Struct( + "certificate_authorities", + UBInt16("length"), + Bytes("certificate_authorities", lambda ctx: ctx.length), +) + +CertificateRequest = Struct( + "CertificateRequest", + ClientCertificateType, + SupportedSignatureAlgorithms, + DistinguishedName, +) + +ServerDHParams = Struct( + "ServerDHParams", + UBInt16("dh_p_length"), + Bytes("dh_p", lambda ctx: ctx.dh_p_length), + UBInt16("dh_g_length"), + Bytes("dh_g", lambda ctx: ctx.dh_g_length), + UBInt16("dh_Ys_length"), + Bytes("dh_Ys", lambda ctx: ctx.dh_Ys_length), +) + +PreMasterSecret = Struct( + "pre_master_secret", + ProtocolVersion, + Bytes("random_bytes", 46), +) + +ASN1Cert = Struct( + "ASN1Cert", + UBInt32("length"), # TODO: Reject packets with length not in 1..2^24-1 + Bytes("asn1_cert", lambda ctx: ctx.length), +) + +Certificate = Struct( + "Certificate", # TODO: Reject packets with length > 2 ** 24 - 1 + UBInt32("certificates_length"), + Bytes("certificates_bytes", lambda ctx: ctx.certificates_length), +) + +Handshake = Struct( + "Handshake", + UBInt8("msg_type"), + UBInt24("length"), # TODO: Reject packets with length > 2 ** 24 + Bytes("body", lambda ctx: ctx.length), +) + +Alert = Struct( + "Alert", + UBInt8("level"), + UBInt8("description"), +) |