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4e81083bb4
i2pd/Reseed.cpp
orignal 4e81083bb4 AES256 cipher template
2015-04-01 12:56:41 -04:00

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#include <string.h>
#include <fstream>
#include <sstream>
#include <boost/regex.hpp>
#include <boost/filesystem.hpp>
#include <boost/lexical_cast.hpp>
#include <cryptopp/asn.h>
#include <cryptopp/base64.h>
#include <cryptopp/crc.h>
#include <cryptopp/hmac.h>
#include <cryptopp/zinflate.h>
#include "I2PEndian.h"
#include "Reseed.h"
#include "Log.h"
#include "Identity.h"
#include "CryptoConst.h"
#include "NetDb.h"
#include "util.h"
namespace i2p
{
namespace data
{
static std::vector<std::string> httpReseedHostList = {
// "http://193.150.121.66/netDb/", // unstable
// "http://us.reseed.i2p2.no/", // misconfigured, not serving reseed data
// "http://jp.reseed.i2p2.no/", // Really outdated RIs
"http://netdb.i2p2.no/", // only SU3 (v2) support
"http://i2p.mooo.com/netDb/",
"http://uk.reseed.i2p2.no/",
"http://i2p-netdb.innovatio.no/"
};
//TODO: Remember to add custom port support. Not all serves on 443
static std::vector<std::string> httpsReseedHostList = {
// "https://193.150.121.66/netDb/", // unstable
// "https://i2p-netdb.innovatio.no/",// Vuln to POODLE
"https://netdb.i2p2.no/", // Only SU3 (v2) support
"https://reseed.i2p-projekt.de/", // Only HTTPS
"https://cowpuncher.drollette.com/netdb/", // Only HTTPS and SU3 (v2) support -- will move to a new location
// following hosts are fine but don't support AES256
/*"https://i2p.mooo.com/netDb/",
"https://link.mx24.eu/", // Only HTTPS and SU3 (v2) support
"https://i2pseed.zarrenspry.info/", // Only HTTPS and SU3 (v2) support
"https://ieb9oopo.mooo.com/" // Only HTTPS and SU3 (v2) support*/
};
Reseeder::Reseeder()
{
}
Reseeder::~Reseeder()
{
}
bool Reseeder::reseedNow()
{
// This method is deprecated
try
{
std::string reseedHost = httpReseedHostList[(rand() % httpReseedHostList.size())];
LogPrint("Reseeding from ", reseedHost);
std::string content = i2p::util::http::httpRequest(reseedHost);
if (content == "")
{
LogPrint("Reseed failed");
return false;
}
boost::regex e("<\\s*A\\s+[^>]*href\\s*=\\s*\"([^\"]*)\"", boost::regex::normal | boost::regbase::icase);
boost::sregex_token_iterator i(content.begin(), content.end(), e, 1);
boost::sregex_token_iterator j;
//TODO: Ugly code, try to clean up.
//TODO: Try to reduce N number of variables
std::string name;
std::string routerInfo;
std::string tmpUrl;
std::string filename;
std::string ignoreFileSuffix = ".su3";
boost::filesystem::path root = i2p::util::filesystem::GetDataDir();
while (i != j)
{
name = *i++;
if (name.find(ignoreFileSuffix)!=std::string::npos)
continue;
LogPrint("Downloading ", name);
tmpUrl = reseedHost;
tmpUrl.append(name);
routerInfo = i2p::util::http::httpRequest(tmpUrl);
if (routerInfo.size()==0)
continue;
filename = root.string();
#ifndef _WIN32
filename += "/netDb/r";
#else
filename += "\\netDb\\r";
#endif
filename += name.at(11); // first char in id
#ifndef _WIN32
filename.append("/");
#else
filename.append("\\");
#endif
filename.append(name.c_str());
std::ofstream outfile (filename, std::ios::binary);
outfile << routerInfo;
outfile.close();
}
return true;
}
catch (std::exception& ex)
{
//TODO: error reporting
return false;
}
return false;
}
int Reseeder::ReseedNowSU3 ()
{
CryptoPP::AutoSeededRandomPool rnd;
auto ind = rnd.GenerateWord32 (0, httpReseedHostList.size() - 1 + httpsReseedHostList.size () - 1);
std::string reseedHost = (ind < httpReseedHostList.size()) ? httpReseedHostList[ind] :
httpsReseedHostList[ind - httpReseedHostList.size()];
return ReseedFromSU3 (reseedHost, ind >= httpReseedHostList.size());
}
int Reseeder::ReseedFromSU3 (const std::string& host, bool https)
{
std::string url = host + "i2pseeds.su3";
LogPrint (eLogInfo, "Dowloading SU3 from ", host);
std::string su3 = https ? HttpsRequest (url) : i2p::util::http::httpRequest (url);
if (su3.length () > 0)
{
std::stringstream s(su3);
return ProcessSU3Stream (s);
}
else
{
LogPrint (eLogWarning, "SU3 download failed");
return 0;
}
}
int Reseeder::ProcessSU3File (const char * filename)
{
std::ifstream s(filename, std::ifstream::binary);
if (s.is_open ())
return ProcessSU3Stream (s);
else
{
LogPrint (eLogError, "Can't open file ", filename);
return 0;
}
}
const char SU3_MAGIC_NUMBER[]="I2Psu3";
const uint32_t ZIP_HEADER_SIGNATURE = 0x04034B50;
const uint32_t ZIP_CENTRAL_DIRECTORY_HEADER_SIGNATURE = 0x02014B50;
const uint16_t ZIP_BIT_FLAG_DATA_DESCRIPTOR = 0x0008;
int Reseeder::ProcessSU3Stream (std::istream& s)
{
char magicNumber[7];
s.read (magicNumber, 7); // magic number and zero byte 6
if (strcmp (magicNumber, SU3_MAGIC_NUMBER))
{
LogPrint (eLogError, "Unexpected SU3 magic number");
return 0;
}
s.seekg (1, std::ios::cur); // su3 file format version
SigningKeyType signatureType;
s.read ((char *)&signatureType, 2); // signature type
signatureType = be16toh (signatureType);
uint16_t signatureLength;
s.read ((char *)&signatureLength, 2); // signature length
signatureLength = be16toh (signatureLength);
s.seekg (1, std::ios::cur); // unused
uint8_t versionLength;
s.read ((char *)&versionLength, 1); // version length
s.seekg (1, std::ios::cur); // unused
uint8_t signerIDLength;
s.read ((char *)&signerIDLength, 1); // signer ID length
uint64_t contentLength;
s.read ((char *)&contentLength, 8); // content length
contentLength = be64toh (contentLength);
s.seekg (1, std::ios::cur); // unused
uint8_t fileType;
s.read ((char *)&fileType, 1); // file type
if (fileType != 0x00) // zip file
{
LogPrint (eLogError, "Can't handle file type ", (int)fileType);
return 0;
}
s.seekg (1, std::ios::cur); // unused
uint8_t contentType;
s.read ((char *)&contentType, 1); // content type
if (contentType != 0x03) // reseed data
{
LogPrint (eLogError, "Unexpected content type ", (int)contentType);
return 0;
}
s.seekg (12, std::ios::cur); // unused
s.seekg (versionLength, std::ios::cur); // skip version
char signerID[256];
s.read (signerID, signerIDLength); // signerID
signerID[signerIDLength] = 0;
//try to verify signature
auto it = m_SigningKeys.find (signerID);
if (it != m_SigningKeys.end ())
{
// TODO: implement all signature types
if (signatureType == SIGNING_KEY_TYPE_RSA_SHA512_4096)
{
size_t pos = s.tellg ();
size_t tbsLen = pos + contentLength;
uint8_t * tbs = new uint8_t[tbsLen];
s.seekg (0, std::ios::beg);
s.read ((char *)tbs, tbsLen);
uint8_t * signature = new uint8_t[signatureLength];
s.read ((char *)signature, signatureLength);
// RSA-raw
i2p::crypto::RSASHA5124096RawVerifier verifier(it->second);
verifier.Update (tbs, tbsLen);
if (!verifier.Verify (signature))
LogPrint (eLogWarning, "SU3 signature verification failed");
delete[] signature;
delete[] tbs;
s.seekg (pos, std::ios::beg);
}
else
LogPrint (eLogWarning, "Signature type ", signatureType, " is not supported");
}
else
LogPrint (eLogWarning, "Certificate for ", signerID, " not loaded");
// handle content
int numFiles = 0;
size_t contentPos = s.tellg ();
while (!s.eof ())
{
uint32_t signature;
s.read ((char *)&signature, 4);
signature = le32toh (signature);
if (signature == ZIP_HEADER_SIGNATURE)
{
// next local file
s.seekg (2, std::ios::cur); // version
uint16_t bitFlag;
s.read ((char *)&bitFlag, 2);
bitFlag = le16toh (bitFlag);
uint16_t compressionMethod;
s.read ((char *)&compressionMethod, 2);
compressionMethod = le16toh (compressionMethod);
s.seekg (4, std::ios::cur); // skip fields we don't care about
uint32_t compressedSize, uncompressedSize;
uint8_t crc32[4];
s.read ((char *)crc32, 4);
s.read ((char *)&compressedSize, 4);
compressedSize = le32toh (compressedSize);
s.read ((char *)&uncompressedSize, 4);
uncompressedSize = le32toh (uncompressedSize);
uint16_t fileNameLength, extraFieldLength;
s.read ((char *)&fileNameLength, 2);
fileNameLength = le16toh (fileNameLength);
s.read ((char *)&extraFieldLength, 2);
extraFieldLength = le16toh (extraFieldLength);
char localFileName[255];
s.read (localFileName, fileNameLength);
localFileName[fileNameLength] = 0;
s.seekg (extraFieldLength, std::ios::cur);
// take care about data desriptor if presented
if (bitFlag & ZIP_BIT_FLAG_DATA_DESCRIPTOR)
{
size_t pos = s.tellg ();
if (!FindZipDataDescriptor (s))
{
LogPrint (eLogError, "SU3 archive data descriptor not found");
return numFiles;
}
s.read ((char *)crc32, 4);
s.read ((char *)&compressedSize, 4);
compressedSize = le32toh (compressedSize) + 4; // ??? we must consider signature as part of compressed data
s.read ((char *)&uncompressedSize, 4);
uncompressedSize = le32toh (uncompressedSize);
// now we know compressed and uncompressed size
s.seekg (pos, std::ios::beg); // back to compressed data
}
LogPrint (eLogDebug, "Proccessing file ", localFileName, " ", compressedSize, " bytes");
if (!compressedSize)
{
LogPrint (eLogWarning, "Unexpected size 0. Skipped");
continue;
}
uint8_t * compressed = new uint8_t[compressedSize];
s.read ((char *)compressed, compressedSize);
if (compressionMethod) // we assume Deflate
{
CryptoPP::Inflator decompressor;
decompressor.Put (compressed, compressedSize);
decompressor.MessageEnd();
if (decompressor.MaxRetrievable () <= uncompressedSize)
{
uint8_t * uncompressed = new uint8_t[uncompressedSize];
decompressor.Get (uncompressed, uncompressedSize);
if (CryptoPP::CRC32().VerifyDigest (crc32, uncompressed, uncompressedSize))
{
i2p::data::netdb.AddRouterInfo (uncompressed, uncompressedSize);
numFiles++;
}
else
LogPrint (eLogError, "CRC32 verification failed");
delete[] uncompressed;
}
else
LogPrint (eLogError, "Actual uncompressed size ", decompressor.MaxRetrievable (), " exceed ", uncompressedSize, " from header");
}
else // no compression
{
i2p::data::netdb.AddRouterInfo (compressed, compressedSize);
numFiles++;
}
delete[] compressed;
if (bitFlag & ZIP_BIT_FLAG_DATA_DESCRIPTOR)
s.seekg (12, std::ios::cur); // skip data descriptor section if presented (12 = 16 - 4)
}
else
{
if (signature != ZIP_CENTRAL_DIRECTORY_HEADER_SIGNATURE)
LogPrint (eLogWarning, "Missing zip central directory header");
break; // no more files
}
size_t end = s.tellg ();
if (end - contentPos >= contentLength)
break; // we are beyond contentLength
}
return numFiles;
}
const uint8_t ZIP_DATA_DESCRIPTOR_SIGNATURE[] = { 0x50, 0x4B, 0x07, 0x08 };
bool Reseeder::FindZipDataDescriptor (std::istream& s)
{
size_t nextInd = 0;
while (!s.eof ())
{
uint8_t nextByte;
s.read ((char *)&nextByte, 1);
if (nextByte == ZIP_DATA_DESCRIPTOR_SIGNATURE[nextInd])
{
nextInd++;
if (nextInd >= sizeof (ZIP_DATA_DESCRIPTOR_SIGNATURE))
return true;
}
else
nextInd = 0;
}
return false;
}
const char CERTIFICATE_HEADER[] = "-----BEGIN CERTIFICATE-----";
const char CERTIFICATE_FOOTER[] = "-----END CERTIFICATE-----";
void Reseeder::LoadCertificate (const std::string& filename)
{
std::ifstream s(filename, std::ifstream::binary);
if (s.is_open ())
{
s.seekg (0, std::ios::end);
size_t len = s.tellg ();
s.seekg (0, std::ios::beg);
char buf[2048];
s.read (buf, len);
std::string cert (buf, len);
// assume file in pem format
auto pos1 = cert.find (CERTIFICATE_HEADER);
auto pos2 = cert.find (CERTIFICATE_FOOTER);
if (pos1 == std::string::npos || pos2 == std::string::npos)
{
LogPrint (eLogError, "Malformed certificate file");
return;
}
pos1 += strlen (CERTIFICATE_HEADER);
pos2 -= pos1;
std::string base64 = cert.substr (pos1, pos2);
CryptoPP::ByteQueue queue;
CryptoPP::Base64Decoder decoder; // regular base64 rather than I2P
decoder.Attach (new CryptoPP::Redirector (queue));
decoder.Put ((const uint8_t *)base64.data(), base64.length());
decoder.MessageEnd ();
LoadCertificate (queue);
}
else
LogPrint (eLogError, "Can't open certificate file ", filename);
}
std::string Reseeder::LoadCertificate (CryptoPP::ByteQueue& queue)
{
// extract X.509
CryptoPP::BERSequenceDecoder x509Cert (queue);
CryptoPP::BERSequenceDecoder tbsCert (x509Cert);
// version
uint32_t ver;
CryptoPP::BERGeneralDecoder context (tbsCert, CryptoPP::CONTEXT_SPECIFIC | CryptoPP::CONSTRUCTED);
CryptoPP::BERDecodeUnsigned<uint32_t>(context, ver, CryptoPP::INTEGER);
// serial
CryptoPP::Integer serial;
serial.BERDecode(tbsCert);
// signature
CryptoPP::BERSequenceDecoder signature (tbsCert);
signature.SkipAll();
// issuer
std::string name;
CryptoPP::BERSequenceDecoder issuer (tbsCert);
{
CryptoPP::BERSetDecoder c (issuer); c.SkipAll();
CryptoPP::BERSetDecoder st (issuer); st.SkipAll();
CryptoPP::BERSetDecoder l (issuer); l.SkipAll();
CryptoPP::BERSetDecoder o (issuer); o.SkipAll();
CryptoPP::BERSetDecoder ou (issuer); ou.SkipAll();
CryptoPP::BERSetDecoder cn (issuer);
{
CryptoPP::BERSequenceDecoder attributes (cn);
{
CryptoPP::BERGeneralDecoder ident(attributes, CryptoPP::OBJECT_IDENTIFIER);
ident.SkipAll ();
CryptoPP::BERDecodeTextString (attributes, name, CryptoPP::UTF8_STRING);
}
}
}
issuer.SkipAll();
// validity
CryptoPP::BERSequenceDecoder validity (tbsCert);
validity.SkipAll();
// subject
CryptoPP::BERSequenceDecoder subject (tbsCert);
subject.SkipAll();
// public key
CryptoPP::BERSequenceDecoder publicKey (tbsCert);
{
CryptoPP::BERSequenceDecoder ident (publicKey);
ident.SkipAll ();
CryptoPP::BERGeneralDecoder key (publicKey, CryptoPP::BIT_STRING);
key.Skip (1); // FIXME: probably bug in crypto++
CryptoPP::BERSequenceDecoder keyPair (key);
CryptoPP::Integer n;
n.BERDecode (keyPair);
if (name.length () > 0)
{
PublicKey value;
n.Encode (value, 512);
m_SigningKeys[name] = value;
}
else
LogPrint (eLogWarning, "Unknown issuer. Skipped");
}
publicKey.SkipAll();
tbsCert.SkipAll();
x509Cert.SkipAll();
return name;
}
void Reseeder::LoadCertificates ()
{
boost::filesystem::path reseedDir = i2p::util::filesystem::GetCertificatesDir() / "reseed";
if (!boost::filesystem::exists (reseedDir))
{
LogPrint (eLogWarning, "Reseed certificates not loaded. ", reseedDir, " doesn't exist");
return;
}
int numCertificates = 0;
boost::filesystem::directory_iterator end; // empty
for (boost::filesystem::directory_iterator it (reseedDir); it != end; ++it)
{
if (boost::filesystem::is_regular_file (it->status()) && it->path ().extension () == ".crt")
{
LoadCertificate (it->path ().string ());
numCertificates++;
}
}
LogPrint (eLogInfo, numCertificates, " certificates loaded");
}
std::string Reseeder::HttpsRequest (const std::string& address)
{
i2p::util::http::url u(address);
TlsSession session (u.host_, 443);
// send request
std::stringstream ss;
ss << "GET " << u.path_ << " HTTP/1.1\r\nHost: " << u.host_
<< "\r\nAccept: */*\r\n" << "User-Agent: Wget/1.11.4\r\n" << "Connection: close\r\n\r\n";
session.Send ((uint8_t *)ss.str ().c_str (), ss.str ().length ());
// read response
std::stringstream rs;
while (session.Receive (rs))
;
return i2p::util::http::GetHttpContent (rs);
}
//-------------------------------------------------------------
template<class Hash>
class TlsCipher_AES_256_CBC: public TlsCipher
{
public:
TlsCipher_AES_256_CBC (uint8_t * masterSecret, uint8_t * random): // master secret - 48 bytes, random - 64 bytes
m_Seqn (0)
{
uint8_t keys[128]; // clientMACKey(32 or 20), serverMACKey(32 or 20), clientKey(32), serverKey(32)
// expand master secret
TlsSession::PRF (masterSecret, "key expansion", random, 64, 128, keys);
memcpy (m_MacKey, keys, Hash::DIGESTSIZE);
m_Encryption.SetKey (keys + 2*Hash::DIGESTSIZE);
m_Decryption.SetKey (keys + 2*Hash::DIGESTSIZE + 32);
}
void CalculateMAC (uint8_t type, const uint8_t * buf, size_t len, uint8_t * mac)
{
uint8_t header[13]; // seqn (8) + type (1) + version (2) + length (2)
htobe64buf (header, m_Seqn);
header[8] = type; header[9] = 3; header[10] = 3; // 3,3 means TLS 1.2
htobe16buf (header + 11, len);
CryptoPP::HMAC<Hash> hmac (m_MacKey, Hash::DIGESTSIZE);
hmac.Update (header, 13);
hmac.Update (buf, len);
hmac.Final (mac);
m_Seqn++;
}
size_t Encrypt (const uint8_t * in, size_t len, const uint8_t * mac, uint8_t * out)
{
size_t size = 0;
m_Rnd.GenerateBlock (out, 16); // iv
size += 16;
m_Encryption.SetIV (out);
memcpy (out + size, in, len);
size += len;
memcpy (out + size, mac, Hash::DIGESTSIZE);
size += Hash::DIGESTSIZE;
uint8_t paddingSize = size + 1;
paddingSize &= 0x0F; // %16
if (paddingSize > 0) paddingSize = 16 - paddingSize;
memset (out + size, paddingSize, paddingSize + 1); // paddind and last byte are equal to padding size
size += paddingSize + 1;
m_Encryption.Encrypt (out + 16, size - 16, out + 16);
return size;
}
size_t Decrypt (uint8_t * buf, size_t len) // payload is buf + 16
{
m_Decryption.SetIV (buf);
m_Decryption.Decrypt (buf + 16, len - 16, buf + 16);
return len - 16 - Hash::DIGESTSIZE - buf[len -1] - 1; // IV(16), mac(32 or 20) and padding
}
private:
uint64_t m_Seqn;
CryptoPP::AutoSeededRandomPool m_Rnd;
i2p::crypto::CBCEncryption m_Encryption;
i2p::crypto::CBCDecryption m_Decryption;
uint8_t m_MacKey[Hash::DIGESTSIZE]; // client
};
TlsSession::TlsSession (const std::string& host, int port):
m_Cipher (nullptr)
{
m_Site.connect(host, boost::lexical_cast<std::string>(port));
if (m_Site.good ())
{
Handshake ();
}
else
LogPrint (eLogError, "Can't connect to ", host, ":", port);
}
TlsSession::~TlsSession ()
{
delete m_Cipher;
}
void TlsSession::Handshake ()
{
static uint8_t clientHello[] =
{
0x16, // handshake
0x03, 0x03, // version (TLS 1.2)
0x00, 0x2F, // length of handshake
// handshake
0x01, // handshake type (client hello)
0x00, 0x00, 0x2B, // length of handshake payload
// client hello
0x03, 0x03, // highest version supported (TLS 1.2)
0x45, 0xFA, 0x01, 0x19, 0x74, 0x55, 0x18, 0x36,
0x42, 0x05, 0xC1, 0xDD, 0x4A, 0x21, 0x80, 0x80,
0xEC, 0x37, 0x11, 0x93, 0x16, 0xF4, 0x66, 0x00,
0x12, 0x67, 0xAB, 0xBA, 0xFF, 0x29, 0x13, 0x9E, // 32 random bytes
0x00, // session id length
0x00, 0x02, // chiper suites length
0x00, 0x3D, // RSA_WITH_AES_256_CBC_SHA256
0x01, // compression methods length
0x00, // no compression
0x00, 0x00 // extensions length
};
static uint8_t changeCipherSpecs[] =
{
0x14, // change cipher specs
0x03, 0x03, // version (TLS 1.2)
0x00, 0x01, // length
0x01 // type
};
static uint8_t finished[] =
{
0x16, // handshake
0x03, 0x03, // version (TLS 1.2)
0x00, 0x50, // length of handshake (80 bytes)
// handshake (encrypted)
// unencrypted context
// 0x14 handshake type (finished)
// 0x00, 0x00, 0x0C length of handshake payload
// 12 bytes of verified data
};
// send ClientHello
m_Site.write ((char *)clientHello, sizeof (clientHello));
m_FinishedHash.Update (clientHello + 5, sizeof (clientHello) - 5);
// read ServerHello
uint8_t type;
m_Site.read ((char *)&type, 1);
uint16_t version;
m_Site.read ((char *)&version, 2);
uint16_t length;
m_Site.read ((char *)&length, 2);
length = be16toh (length);
char * serverHello = new char[length];
m_Site.read (serverHello, length);
m_FinishedHash.Update ((uint8_t *)serverHello, length);
uint8_t serverRandom[32];
if (serverHello[0] == 0x02) // handshake type server hello
memcpy (serverRandom, serverHello + 6, 32);
else
LogPrint (eLogError, "Unexpected handshake type ", (int)serverHello[0]);
delete[] serverHello;
// read Certificate
m_Site.read ((char *)&type, 1);
m_Site.read ((char *)&version, 2);
m_Site.read ((char *)&length, 2);
length = be16toh (length);
char * certificate = new char[length];
m_Site.read (certificate, length);
m_FinishedHash.Update ((uint8_t *)certificate, length);
CryptoPP::RSA::PublicKey publicKey;
// 0 - handshake type
// 1 - 3 - handshake payload length
// 4 - 6 - length of array of certificates
// 7 - 9 - length of certificate
if (certificate[0] == 0x0B) // handshake type certificate
publicKey = ExtractPublicKey ((uint8_t *)certificate + 10, length - 10);
else
LogPrint (eLogError, "Unexpected handshake type ", (int)certificate[0]);
delete[] certificate;
// read ServerHelloDone
m_Site.read ((char *)&type, 1);
m_Site.read ((char *)&version, 2);
m_Site.read ((char *)&length, 2);
length = be16toh (length);
char * serverHelloDone = new char[length];
m_Site.read (serverHelloDone, length);
m_FinishedHash.Update ((uint8_t *)serverHelloDone, length);
if (serverHelloDone[0] != 0x0E) // handshake type hello done
LogPrint (eLogError, "Unexpected handshake type ", (int)serverHelloDone[0]);
delete[] serverHelloDone;
// our turn now
// generate secret key
uint8_t secret[48];
secret[0] = 3; secret[1] = 3; // version
CryptoPP::AutoSeededRandomPool rnd;
rnd.GenerateBlock (secret + 2, 46); // 46 random bytes
// encrypt RSA
CryptoPP::RSAES_PKCS1v15_Encryptor encryptor(publicKey);
size_t encryptedLen = encryptor.CiphertextLength (48); // number of bytes for encrypted 48 bytes, usually 256 (2048 bits key)
uint8_t * encrypted = new uint8_t[encryptedLen + 2]; // + 2 bytes for length
htobe16buf (encrypted, encryptedLen); // first two bytes means length
encryptor.Encrypt (rnd, secret, 48, encrypted + 2);
// send ClientKeyExchange
// 0x10 - handshake type "client key exchange"
SendHandshakeMsg (0x10, encrypted, encryptedLen + 2);
delete[] encrypted;
// send ChangeCipherSpecs
m_Site.write ((char *)changeCipherSpecs, sizeof (changeCipherSpecs));
// calculate master secret
uint8_t masterSecret[48], random[64];
memcpy (random, clientHello + 11, 32);
memcpy (random + 32, serverRandom, 32);
PRF (secret, "master secret", random, 64, 48, masterSecret);
// invert random for keys
memcpy (random, serverRandom, 32);
memcpy (random + 32, clientHello + 11, 32);
// create cipher
m_Cipher = new TlsCipher_AES_256_CBC<CryptoPP::SHA256> (masterSecret, random);
// send finished
uint8_t finishedHashDigest[32], finishedPayload[40], encryptedPayload[80];
finishedPayload[0] = 0x14; // handshake type (finished)
finishedPayload[1] = 0; finishedPayload[2] = 0; finishedPayload[3] = 0x0C; // 12 bytes
m_FinishedHash.Final (finishedHashDigest);
PRF (masterSecret, "client finished", finishedHashDigest, 32, 12, finishedPayload + 4);
uint8_t mac[32];
m_Cipher->CalculateMAC (0x16, finishedPayload, 16, mac);
size_t encryptedPayloadSize = m_Cipher->Encrypt (finishedPayload, 16, mac, encryptedPayload);
m_Site.write ((char *)finished, sizeof (finished));
m_Site.write ((char *)encryptedPayload, encryptedPayloadSize);
// read ChangeCipherSpecs
uint8_t changeCipherSpecs1[6];
m_Site.read ((char *)changeCipherSpecs1, 6);
// read finished
m_Site.read ((char *)&type, 1);
m_Site.read ((char *)&version, 2);
m_Site.read ((char *)&length, 2);
length = be16toh (length);
char * finished1 = new char[length];
m_Site.read (finished1, length);
delete[] finished1;
}
void TlsSession::SendHandshakeMsg (uint8_t handshakeType, uint8_t * data, size_t len)
{
uint8_t handshakeHeader[9];
handshakeHeader[0] = 0x16; // handshake
handshakeHeader[1] = 0x03; handshakeHeader[2] = 0x03; // version is always TLS 1.2 (3,3)
htobe16buf (handshakeHeader + 3, len + 4); // length of payload
//payload starts
handshakeHeader[5] = handshakeType; // handshake type
handshakeHeader[6] = 0; // highest byte of payload length is always zero
htobe16buf (handshakeHeader + 7, len); // length of data
m_Site.write ((char *)handshakeHeader, 9);
m_FinishedHash.Update (handshakeHeader + 5, 4); // only payload counts
m_Site.write ((char *)data, len);
m_FinishedHash.Update (data, len);
}
void TlsSession::PRF (const uint8_t * secret, const char * label, const uint8_t * random, size_t randomLen,
size_t len, uint8_t * buf)
{
// secret is assumed 48 bytes
// random is not more than 64 bytes
CryptoPP::HMAC<CryptoPP::SHA256> hmac (secret, 48);
uint8_t seed[96]; size_t seedLen;
seedLen = strlen (label);
memcpy (seed, label, seedLen);
memcpy (seed + seedLen, random, randomLen);
seedLen += randomLen;
size_t offset = 0;
uint8_t a[128];
hmac.CalculateDigest (a, seed, seedLen);
while (offset < len)
{
memcpy (a + 32, seed, seedLen);
hmac.CalculateDigest (buf + offset, a, seedLen + 32);
offset += 32;
hmac.CalculateDigest (a, a, 32);
}
}
CryptoPP::RSA::PublicKey TlsSession::ExtractPublicKey (const uint8_t * certificate, size_t len)
{
CryptoPP::ByteQueue queue;
queue.Put (certificate, len);
queue.MessageEnd ();
// extract X.509
CryptoPP::BERSequenceDecoder x509Cert (queue);
CryptoPP::BERSequenceDecoder tbsCert (x509Cert);
// version
uint32_t ver;
CryptoPP::BERGeneralDecoder context (tbsCert, CryptoPP::CONTEXT_SPECIFIC | CryptoPP::CONSTRUCTED);
CryptoPP::BERDecodeUnsigned<uint32_t>(context, ver, CryptoPP::INTEGER);
// serial
CryptoPP::Integer serial;
serial.BERDecode(tbsCert);
// signature
CryptoPP::BERSequenceDecoder signature (tbsCert);
signature.SkipAll();
// issuer
CryptoPP::BERSequenceDecoder issuer (tbsCert);
issuer.SkipAll();
// validity
CryptoPP::BERSequenceDecoder validity (tbsCert);
validity.SkipAll();
// subject
CryptoPP::BERSequenceDecoder subject (tbsCert);
subject.SkipAll();
// public key
CryptoPP::BERSequenceDecoder publicKey (tbsCert);
CryptoPP::BERSequenceDecoder ident (publicKey);
ident.SkipAll ();
CryptoPP::BERGeneralDecoder key (publicKey, CryptoPP::BIT_STRING);
key.Skip (1); // FIXME: probably bug in crypto++
CryptoPP::BERSequenceDecoder keyPair (key);
CryptoPP::Integer n, e;
n.BERDecode (keyPair);
e.BERDecode (keyPair);
CryptoPP::RSA::PublicKey ret;
ret.Initialize (n, e);
return ret;
}
void TlsSession::Send (const uint8_t * buf, size_t len)
{
uint8_t * out = new uint8_t[len + 64 + 5]; // 64 = 32 mac + 16 iv + upto 16 padding, 5 = header
out[0] = 0x17; // application data
out[1] = 0x03; out[2] = 0x03; // version
uint8_t mac[32];
m_Cipher->CalculateMAC (0x17, buf, len, mac);
size_t encryptedLen = m_Cipher->Encrypt (buf, len, mac, out + 5);
htobe16buf (out + 3, encryptedLen);
m_Site.write ((char *)out, encryptedLen + 5);
delete[] out;
}
bool TlsSession::Receive (std::ostream& rs)
{
if (m_Site.eof ()) return false;
uint8_t type; uint16_t version, length;
m_Site.read ((char *)&type, 1);
m_Site.read ((char *)&version, 2);
m_Site.read ((char *)&length, 2);
length = be16toh (length);
uint8_t * buf = new uint8_t[length];
m_Site.read ((char *)buf, length);
size_t decryptedLen = m_Cipher->Decrypt (buf, length);
rs.write ((char *)buf + 16, decryptedLen);
delete[] buf;
return true;
}
}
}
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