diff options
Diffstat (limited to 'src/ssl/rec_read.cpp')
| -rw-r--r-- | src/ssl/rec_read.cpp | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/src/ssl/rec_read.cpp b/src/ssl/rec_read.cpp new file mode 100644 index 000000000..95059dbf2 --- /dev/null +++ b/src/ssl/rec_read.cpp @@ -0,0 +1,204 @@ +/** +* TLS Record Reading +* (C) 2004-2006 Jack Lloyd +* +* Released under the terms of the Botan license +*/ + +#include <botan/tls_record.h> +#include <botan/lookup.h> +#include <botan/loadstor.h> +#include <botan/internal/debug.h> + +namespace Botan { + +/** +* Record_Reader Constructor +*/ +Record_Reader::Record_Reader(Socket& sock) : socket(sock) + { + reset(); + } + +/** +* Reset the state +*/ +void Record_Reader::reset() + { + compress.reset(); + cipher.reset(); + mac.reset(); + do_compress = false; + mac_size = pad_amount = 0; + major = minor = 0; + seq_no = 0; + } + +/** +* Set the version to use +*/ +void Record_Reader::set_version(Version_Code version) + { + if(version != SSL_V3 && version != TLS_V10) + throw Invalid_Argument("Record_Reader: Invalid protocol version"); + + major = (version >> 8) & 0xFF; + minor = (version & 0xFF); + } + +/** +* Set the compression algorithm +*/ +void Record_Reader::set_compressor(Filter* compressor) + { + compress.append(compressor); + do_compress = true; + } + +/** +* Set the keys for reading +*/ +void Record_Reader::set_keys(const CipherSuite& suite, const SessionKeys& keys, + Connection_Side side) + { + cipher.reset(); + mac.reset(); + + SymmetricKey mac_key, cipher_key; + InitializationVector iv; + + if(side == CLIENT) + { + cipher_key = keys.server_cipher_key(); + iv = keys.server_iv(); + mac_key = keys.server_mac_key(); + } + else + { + cipher_key = keys.client_cipher_key(); + iv = keys.client_iv(); + mac_key = keys.client_mac_key(); + } + + const std::string cipher_algo = suite.cipher_algo(); + const std::string mac_algo = suite.mac_algo(); + + if(have_block_cipher(cipher_algo)) + { + cipher.append(get_cipher( + cipher_algo + "/CBC/NoPadding", + cipher_key, iv, DECRYPTION) + ); + pad_amount = block_size_of(cipher_algo); + } + else if(have_stream_cipher(cipher_algo)) + { + cipher.append(get_cipher(cipher_algo, cipher_key, DECRYPTION)); + pad_amount = 0; + } + else + throw Invalid_Argument("Record_Reader: Unknown cipher " + cipher_algo); + + if(have_hash(mac_algo)) + { + if(major == 3 && minor == 0) + mac.append(new MAC_Filter("SSL3-MAC(" + mac_algo + ")", mac_key)); + else + mac.append(new MAC_Filter("HMAC(" + mac_algo + ")", mac_key)); + + mac_size = output_length_of(mac_algo); + } + else + throw Invalid_Argument("Record_Reader: Unknown hash " + mac_algo); + } + +/** +* Retrieve the next record +*/ +SecureVector<byte> Record_Reader::get_record(byte& msg_type) + { + byte header[5] = { 0 }; + + u32bit got = socket.read(header, sizeof(header)); + + if(got == 0) + { + msg_type = CONNECTION_CLOSED; + return SecureVector<byte>(); + } + else if(got != sizeof(header)) + throw Decoding_Error("Record_Reader: Record truncated"); + + msg_type = header[0]; + + const u16bit version = make_u16bit(header[1], header[2]); + + if(major && (header[1] != major || header[2] != minor)) + throw TLS_Exception(PROTOCOL_VERSION, + "Record_Reader: Got unexpected version"); + + SecureVector<byte> buffer(make_u16bit(header[3], header[4])); + if(socket.read(buffer, buffer.size()) != buffer.size()) + throw Decoding_Error("Record_Reader: Record truncated"); + + if(mac_size == 0) + return buffer; + + cipher.process_msg(buffer); + SecureVector<byte> plaintext = cipher.read_all(Pipe::LAST_MESSAGE); + + u32bit pad_size = 0; + if(pad_amount) + { + byte pad_value = plaintext[plaintext.size()-1]; + pad_size = pad_value + 1; + + if(version == SSL_V3) + { + if(pad_value > pad_amount) + throw TLS_Exception(BAD_RECORD_MAC, + "Record_Reader: Bad padding"); + } + else + { + for(u32bit j = 0; j != pad_size; j++) + if(plaintext[plaintext.size()-j-1] != pad_value) + throw TLS_Exception(BAD_RECORD_MAC, + "Record_Reader: Bad padding"); + } + } + + if(plaintext.size() < mac_size + pad_size) + throw Decoding_Error("Record_Reader: Record truncated"); + + const u32bit mac_offset = plaintext.size() - (mac_size + pad_size); + SecureVector<byte> recieved_mac(plaintext.begin() + mac_offset, + mac_size); + + const u16bit plain_length = plaintext.size() - (mac_size + pad_size); + + mac.start_msg(); + for(u32bit j = 0; j != 8; j++) + mac.write(get_byte(j, seq_no)); + mac.write(msg_type); + + if(version != SSL_V3) + for(u32bit j = 0; j != 2; j++) + mac.write(get_byte(j, version)); + + for(u32bit j = 0; j != 2; j++) + mac.write(get_byte(j, plain_length)); + mac.write(plaintext, plain_length); + mac.end_msg(); + + ++seq_no; + + SecureVector<byte> computed_mac = mac.read_all(Pipe::LAST_MESSAGE); + + if(recieved_mac != computed_mac) + throw TLS_Exception(BAD_RECORD_MAC, "Record_Reader: MAC failure"); + + return SecureVector<byte>(plaintext, mac_offset); + } + +} |