static int
readVC( tr_handshake * handshake,
struct evbuffer * inbuf )
{
const uint8_t key[VC_LENGTH] = { 0, 0, 0, 0, 0, 0, 0, 0 };
const int key_len = VC_LENGTH;
uint8_t tmp[VC_LENGTH];
/* note: this works w/o having to `unwind' the buffer if
* we read too much, but it is pretty brute-force.
* it would be nice to make this cleaner. */
for( ; ; )
{
if( evbuffer_get_length( inbuf ) < VC_LENGTH )
{
dbgmsg( handshake, "not enough bytes... returning read_more" );
return READ_LATER;
}
memcpy( tmp, evbuffer_pullup( inbuf, key_len ), key_len );
tr_cryptoDecryptInit( handshake->crypto );
tr_cryptoDecrypt( handshake->crypto, key_len, tmp, tmp );
if( !memcmp( tmp, key, key_len ) )
break;
evbuffer_drain( inbuf, 1 );
}
dbgmsg( handshake, "got it!" );
evbuffer_drain( inbuf, key_len );
setState( handshake, AWAITING_CRYPTO_SELECT );
return READ_NOW;
}
void
tr_peerIoReadBytes( tr_peerIo * io,
struct evbuffer * inbuf,
void * bytes,
size_t byteCount )
{
assert( tr_isPeerIo( io ) );
/* FIXME(libevent2): use evbuffer_get_length() */
assert( EVBUFFER_LENGTH( inbuf ) >= byteCount );
switch( io->encryptionMode )
{
case PEER_ENCRYPTION_NONE:
evbuffer_remove( inbuf, bytes, byteCount );
break;
case PEER_ENCRYPTION_RC4:
/* FIXME(libevent2): loop through calls to evbuffer_get_contiguous_space() + evbuffer_drain() */
tr_cryptoDecrypt( io->crypto, byteCount, EVBUFFER_DATA(inbuf), bytes );
evbuffer_drain(inbuf, byteCount );
break;
default:
assert( 0 );
}
}
static int
test_encrypt_decrypt (void)
{
tr_crypto a, b;
uint8_t hash[SHA_DIGEST_LENGTH];
const char test1[] = { "test1" };
char buf11[sizeof (test1)], buf12[sizeof (test1)];
const char test2[] = { "@#)C$@)#(*%bvkdjfhwbc039bc4603756VB3)" };
char buf21[sizeof (test2)], buf22[sizeof (test2)];
int i;
for (i = 0; i < SHA_DIGEST_LENGTH; ++i)
hash[i] = i;
tr_cryptoConstruct (&a, hash, false);
tr_cryptoConstruct (&b, hash, true);
tr_cryptoComputeSecret (&a, tr_cryptoGetMyPublicKey (&b, &i));
tr_cryptoComputeSecret (&b, tr_cryptoGetMyPublicKey (&a, &i));
tr_cryptoEncryptInit (&a);
tr_cryptoEncrypt (&a, sizeof (test1), test1, buf11);
tr_cryptoDecryptInit (&b);
tr_cryptoDecrypt (&b, sizeof (test1), buf11, buf12);
check_streq (test1, buf12);
tr_cryptoEncryptInit (&b);
tr_cryptoEncrypt (&b, sizeof (test2), test2, buf21);
tr_cryptoDecryptInit (&a);
tr_cryptoDecrypt (&a, sizeof (test2), buf21, buf22);
check_streq (test2, buf22);
tr_cryptoDestruct (&b);
tr_cryptoDestruct (&a);
return 0;
}
static int
readHandshake( tr_handshake * handshake,
struct evbuffer * inbuf )
{
uint8_t pstrlen;
uint8_t * pstr;
uint8_t reserved[HANDSHAKE_FLAGS_LEN];
uint8_t hash[SHA_DIGEST_LENGTH];
dbgmsg( handshake, "payload: need %d, got %zu",
INCOMING_HANDSHAKE_LEN, evbuffer_get_length( inbuf ) );
if( evbuffer_get_length( inbuf ) < INCOMING_HANDSHAKE_LEN )
return READ_LATER;
handshake->haveReadAnythingFromPeer = TRUE;
pstrlen = evbuffer_pullup( inbuf, 1 )[0]; /* peek, don't read. We may be
handing inbuf to AWAITING_YA */
if( pstrlen == 19 ) /* unencrypted */
{
tr_peerIoSetEncryption( handshake->io, PEER_ENCRYPTION_NONE );
if( handshake->encryptionMode == TR_ENCRYPTION_REQUIRED )
{
dbgmsg( handshake,
"peer is unencrypted, and we're disallowing that" );
return tr_handshakeDone( handshake, FALSE );
}
}
else /* encrypted or corrupt */
{
tr_peerIoSetEncryption( handshake->io, PEER_ENCRYPTION_RC4 );
if( tr_peerIoIsIncoming( handshake->io ) )
{
dbgmsg( handshake,
"I think peer is sending us an encrypted handshake..." );
setState( handshake, AWAITING_YA );
return READ_NOW;
}
tr_cryptoDecrypt( handshake->crypto, 1, &pstrlen, &pstrlen );
if( pstrlen != 19 )
{
dbgmsg( handshake,
"I think peer has sent us a corrupt handshake..." );
return tr_handshakeDone( handshake, FALSE );
}
}
evbuffer_drain( inbuf, 1 );
/* pstr (BitTorrent) */
pstr = tr_new( uint8_t, pstrlen + 1 );
tr_peerIoReadBytes( handshake->io, inbuf, pstr, pstrlen );
pstr[pstrlen] = '\0';
if( strcmp( (char*)pstr, "BitTorrent protocol" ) )
{
tr_free( pstr );
return tr_handshakeDone( handshake, FALSE );
}
tr_free( pstr );
/* reserved bytes */
tr_peerIoReadBytes( handshake->io, inbuf, reserved, sizeof( reserved ) );
/**
*** Extensions
**/
tr_peerIoEnableLTEP( handshake->io, HANDSHAKE_HAS_LTEP( reserved ) );
tr_peerIoEnableFEXT( handshake->io, HANDSHAKE_HAS_FASTEXT( reserved ) );
tr_peerIoEnableDHT( handshake->io, HANDSHAKE_HAS_DHT( reserved ) );
/* torrent hash */
tr_peerIoReadBytes( handshake->io, inbuf, hash, sizeof( hash ) );
if( tr_peerIoIsIncoming( handshake->io ) )
{
if( !tr_torrentExists( handshake->session, hash ) )
{
dbgmsg( handshake, "peer is trying to connect to us for a torrent we don't have." );
return tr_handshakeDone( handshake, FALSE );
}
else
{
assert( !tr_peerIoHasTorrentHash( handshake->io ) );
tr_peerIoSetTorrentHash( handshake->io, hash );
}
}
else /* outgoing */
{
assert( tr_peerIoHasTorrentHash( handshake->io ) );
if( memcmp( hash, tr_peerIoGetTorrentHash( handshake->io ),
SHA_DIGEST_LENGTH ) )
{
dbgmsg( handshake, "peer returned the wrong hash. wtf?" );
return tr_handshakeDone( handshake, FALSE );
}
}
/**
*** If it's an incoming message, we need to send a response handshake
**/
if( !handshake->haveSentBitTorrentHandshake )
{
uint8_t msg[HANDSHAKE_SIZE];
buildHandshakeMessage( handshake, msg );
tr_peerIoWriteBytes( handshake->io, msg, sizeof( msg ), FALSE );
handshake->haveSentBitTorrentHandshake = 1;
}
setReadState( handshake, AWAITING_PEER_ID );
return READ_NOW;
}
