static int
test_sha1 (void)
{
uint8_t hash[SHA_DIGEST_LENGTH];
tr_sha1 (hash, "test", 4, NULL);
check (memcmp (hash, "\xa9\x4a\x8f\xe5\xcc\xb1\x9b\xa6\x1c\x4c\x08\x73\xd3\x91\xe9\x87\x98\x2f\xbb\xd3", SHA_DIGEST_LENGTH) == 0);
tr_sha1 (hash, "1", 1, "22", 2, "333", 3, NULL);
check (memcmp (hash, "\x1f\x74\x64\x8e\x50\xa6\xa6\x70\x8e\xc5\x4a\xb3\x27\xa1\x63\xd5\x53\x6b\x7c\xed", SHA_DIGEST_LENGTH) == 0);
return 0;
}
tr_bool
tr_ssha1_matches( const char * source, const char * pass )
{
char * salt;
size_t saltlen;
char * hashed;
uint8_t buf[SHA_DIGEST_LENGTH];
tr_bool result;
/* extract the salt */
saltlen = strlen( source ) - 2*SHA_DIGEST_LENGTH-1;
salt = tr_malloc( saltlen );
memcpy( salt, source + 2*SHA_DIGEST_LENGTH+1, saltlen );
/* hash pass + salt */
hashed = tr_malloc( 2*SHA_DIGEST_LENGTH + saltlen + 2 );
tr_sha1( buf, pass, strlen( pass ), salt, saltlen, NULL );
tr_sha1_to_hex( &hashed[1], buf );
memcpy( hashed + 1+2*SHA_DIGEST_LENGTH, salt, saltlen );
hashed[1+2*SHA_DIGEST_LENGTH + saltlen] = '\0';
hashed[0] = '{';
result = strcmp( source, hashed ) == 0 ? TRUE : FALSE;
tr_free( hashed );
tr_free( salt );
return result;
}
char*
tr_ssha1( const void * plaintext )
{
enum { saltval_len = 8,
salter_len = 64 };
static const char * salter = "0123456789"
"abcdefghijklmnopqrstuvwxyz"
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"./";
size_t i;
unsigned char salt[saltval_len];
uint8_t sha[SHA_DIGEST_LENGTH];
char buf[2*SHA_DIGEST_LENGTH + saltval_len + 2];
tr_cryptoRandBuf( salt, saltval_len );
for( i=0; i<saltval_len; ++i )
salt[i] = salter[ salt[i] % salter_len ];
tr_sha1( sha, plaintext, strlen( plaintext ), salt, saltval_len, NULL );
tr_sha1_to_hex( &buf[1], sha );
memcpy( &buf[1+2*SHA_DIGEST_LENGTH], &salt, saltval_len );
buf[1+2*SHA_DIGEST_LENGTH + saltval_len] = '\0';
buf[0] = '{'; /* signal that this is a hash. this makes saving/restoring
easier */
return tr_strdup( &buf );
}
static int
readYa( tr_handshake * handshake,
struct evbuffer * inbuf )
{
uint8_t ya[KEY_LEN];
uint8_t * walk, outbuf[KEY_LEN + PadB_MAXLEN];
const uint8_t *myKey, *secret;
int len;
dbgmsg( handshake, "in readYa... need %d, have %zu",
KEY_LEN, evbuffer_get_length( inbuf ) );
if( evbuffer_get_length( inbuf ) < KEY_LEN )
return READ_LATER;
/* read the incoming peer's public key */
evbuffer_remove( inbuf, ya, KEY_LEN );
secret = tr_cryptoComputeSecret( handshake->crypto, ya );
memcpy( handshake->mySecret, secret, KEY_LEN );
tr_sha1( handshake->myReq1, "req1", 4, secret, KEY_LEN, NULL );
dbgmsg( handshake, "sending B->A: Diffie Hellman Yb, PadB" );
/* send our public key to the peer */
walk = outbuf;
myKey = tr_cryptoGetMyPublicKey( handshake->crypto, &len );
memcpy( walk, myKey, len );
walk += len;
len = tr_cryptoRandInt( PadB_MAXLEN );
tr_cryptoRandBuf( walk, len );
walk += len;
setReadState( handshake, AWAITING_PAD_A );
tr_peerIoWriteBytes( handshake->io, outbuf, walk - outbuf, FALSE );
return READ_NOW;
}
bool tr_dh_secret_derive(tr_dh_secret_t raw_handle, void const* prepend_data, size_t prepend_data_size, void const* append_data,
size_t append_data_size, uint8_t* hash)
{
TR_ASSERT(raw_handle != NULL);
TR_ASSERT(hash != NULL);
struct tr_dh_secret* handle = raw_handle;
return tr_sha1(hash, prepend_data == NULL ? "" : prepend_data, prepend_data == NULL ? 0 : (int)prepend_data_size,
handle->key, (int)handle->key_length, append_data, append_data == NULL ? 0 : (int)append_data_size, NULL);
}
static int
readCryptoProvide( tr_handshake * handshake,
struct evbuffer * inbuf )
{
/* HASH('req2', SKEY) xor HASH('req3', S), ENCRYPT(VC, crypto_provide,
len(PadC)) */
int i;
uint8_t vc_in[VC_LENGTH];
uint8_t req2[SHA_DIGEST_LENGTH];
uint8_t req3[SHA_DIGEST_LENGTH];
uint8_t obfuscatedTorrentHash[SHA_DIGEST_LENGTH];
uint16_t padc_len = 0;
uint32_t crypto_provide = 0;
const size_t needlen = SHA_DIGEST_LENGTH /* HASH('req1',s) */
+ SHA_DIGEST_LENGTH /* HASH('req2', SKEY) xor
HASH('req3', S) */
+ VC_LENGTH
+ sizeof( crypto_provide )
+ sizeof( padc_len );
tr_torrent * tor = NULL;
if( evbuffer_get_length( inbuf ) < needlen )
return READ_LATER;
/* TODO: confirm they sent HASH('req1',S) here? */
evbuffer_drain( inbuf, SHA_DIGEST_LENGTH );
/* This next piece is HASH('req2', SKEY) xor HASH('req3', S) ...
* we can get the first half of that (the obufscatedTorrentHash)
* by building the latter and xor'ing it with what the peer sent us */
dbgmsg( handshake, "reading obfuscated torrent hash..." );
evbuffer_remove( inbuf, req2, SHA_DIGEST_LENGTH );
tr_sha1( req3, "req3", 4, handshake->mySecret, KEY_LEN, NULL );
for( i = 0; i < SHA_DIGEST_LENGTH; ++i )
obfuscatedTorrentHash[i] = req2[i] ^ req3[i];
if(( tor = tr_torrentFindFromObfuscatedHash( handshake->session, obfuscatedTorrentHash )))
{
const tr_bool clientIsSeed = tr_torrentIsSeed( tor );
const tr_bool peerIsSeed = tr_peerMgrPeerIsSeed( tor, tr_peerIoGetAddress( handshake->io, NULL ) );
dbgmsg( handshake, "got INCOMING connection's encrypted handshake for torrent [%s]",
tr_torrentName( tor ) );
tr_peerIoSetTorrentHash( handshake->io, tor->info.hash );
if( clientIsSeed && peerIsSeed )
{
dbgmsg( handshake, "another seed tried to reconnect to us!" );
return tr_handshakeDone( handshake, FALSE );
}
}
else
{
dbgmsg( handshake, "can't find that torrent..." );
return tr_handshakeDone( handshake, FALSE );
}
/* next part: ENCRYPT(VC, crypto_provide, len(PadC), */
tr_cryptoDecryptInit( handshake->crypto );
tr_peerIoReadBytes( handshake->io, inbuf, vc_in, VC_LENGTH );
tr_peerIoReadUint32( handshake->io, inbuf, &crypto_provide );
handshake->crypto_provide = crypto_provide;
dbgmsg( handshake, "crypto_provide is %d", (int)crypto_provide );
tr_peerIoReadUint16( handshake->io, inbuf, &padc_len );
dbgmsg( handshake, "padc is %d", (int)padc_len );
handshake->pad_c_len = padc_len;
setState( handshake, AWAITING_PAD_C );
return READ_NOW;
}
static int
readYb( tr_handshake * handshake, struct evbuffer * inbuf )
{
int isEncrypted;
const uint8_t * secret;
uint8_t yb[KEY_LEN];
struct evbuffer * outbuf;
size_t needlen = HANDSHAKE_NAME_LEN;
if( evbuffer_get_length( inbuf ) < needlen )
return READ_LATER;
isEncrypted = memcmp( evbuffer_pullup( inbuf, HANDSHAKE_NAME_LEN ), HANDSHAKE_NAME, HANDSHAKE_NAME_LEN );
if( isEncrypted )
{
needlen = KEY_LEN;
if( evbuffer_get_length( inbuf ) < needlen )
return READ_LATER;
}
dbgmsg( handshake, "got a %s handshake",
( isEncrypted ? "encrypted" : "plaintext" ) );
tr_peerIoSetEncryption( handshake->io, isEncrypted ? PEER_ENCRYPTION_RC4
: PEER_ENCRYPTION_NONE );
if( !isEncrypted )
{
setState( handshake, AWAITING_HANDSHAKE );
return READ_NOW;
}
handshake->haveReadAnythingFromPeer = TRUE;
/* compute the secret */
evbuffer_remove( inbuf, yb, KEY_LEN );
secret = tr_cryptoComputeSecret( handshake->crypto, yb );
memcpy( handshake->mySecret, secret, KEY_LEN );
/* now send these: HASH('req1', S), HASH('req2', SKEY) xor HASH('req3', S),
* ENCRYPT(VC, crypto_provide, len(PadC), PadC, len(IA)), ENCRYPT(IA) */
outbuf = evbuffer_new( );
/* HASH('req1', S) */
{
uint8_t req1[SHA_DIGEST_LENGTH];
tr_sha1( req1, "req1", 4, secret, KEY_LEN, NULL );
evbuffer_add( outbuf, req1, SHA_DIGEST_LENGTH );
}
/* HASH('req2', SKEY) xor HASH('req3', S) */
{
int i;
uint8_t req2[SHA_DIGEST_LENGTH];
uint8_t req3[SHA_DIGEST_LENGTH];
uint8_t buf[SHA_DIGEST_LENGTH];
tr_sha1( req2, "req2", 4,
tr_cryptoGetTorrentHash( handshake->crypto ),
SHA_DIGEST_LENGTH, NULL );
tr_sha1( req3, "req3", 4, secret, KEY_LEN, NULL );
for( i = 0; i < SHA_DIGEST_LENGTH; ++i )
buf[i] = req2[i] ^ req3[i];
evbuffer_add( outbuf, buf, SHA_DIGEST_LENGTH );
}
/* ENCRYPT(VC, crypto_provide, len(PadC), PadC
* PadC is reserved for future extensions to the handshake...
* standard practice at this time is for it to be zero-length */
{
uint8_t vc[VC_LENGTH] = { 0, 0, 0, 0, 0, 0, 0, 0 };
tr_peerIoWriteBuf( handshake->io, outbuf, FALSE );
tr_cryptoEncryptInit( handshake->crypto );
tr_peerIoSetEncryption( handshake->io, PEER_ENCRYPTION_RC4 );
evbuffer_add ( outbuf, vc, VC_LENGTH );
evbuffer_add_uint32 ( outbuf, getCryptoProvide( handshake ) );
evbuffer_add_uint16 ( outbuf, 0 );
}
/* ENCRYPT len(IA)), ENCRYPT(IA) */
{
uint8_t msg[HANDSHAKE_SIZE];
buildHandshakeMessage( handshake, msg );
evbuffer_add_uint16 ( outbuf, sizeof( msg ) );
evbuffer_add ( outbuf, msg, sizeof( msg ) );
handshake->haveSentBitTorrentHandshake = 1;
}
/* send it */
tr_cryptoDecryptInit( handshake->crypto );
setReadState( handshake, AWAITING_VC );
tr_peerIoWriteBuf( handshake->io, outbuf, FALSE );
/* cleanup */
evbuffer_free( outbuf );
return READ_LATER;
}
