mirror of
https://github.com/transmission/transmission
synced 2024-12-25 09:13:06 +00:00
(trunk libT) #2658 "encryption improvements" - patch by sadface to make DH handshake ~2x faster. yay!
This commit is contained in:
parent
5df69c898c
commit
196a7ccbb9
1 changed files with 35 additions and 20 deletions
|
@ -69,6 +69,9 @@ tr_sha1( uint8_t * setme,
|
|||
|
||||
#define PRIME_LEN 96
|
||||
|
||||
#define DH_PRIVKEY_LEN_MIN 16
|
||||
#define DH_PRIVKEY_LEN 20
|
||||
|
||||
static const uint8_t dh_P[PRIME_LEN] =
|
||||
{
|
||||
0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC9, 0x0F, 0xDA, 0xA2,
|
||||
|
@ -93,6 +96,7 @@ struct tr_crypto
|
|||
tr_bool mySecretIsSet;
|
||||
uint8_t myPublicKey[KEY_LEN];
|
||||
uint8_t mySecret[KEY_LEN];
|
||||
DH * dh;
|
||||
};
|
||||
|
||||
/**
|
||||
|
@ -108,14 +112,13 @@ struct tr_crypto
|
|||
} \
|
||||
} while( 0 )
|
||||
|
||||
static DH*
|
||||
getSharedDH( void )
|
||||
static void
|
||||
ensureKeyExists( tr_crypto * crypto)
|
||||
{
|
||||
static DH * dh = NULL;
|
||||
|
||||
if( dh == NULL )
|
||||
if( crypto->dh == NULL )
|
||||
{
|
||||
dh = DH_new( );
|
||||
int len, offset;
|
||||
DH * dh = DH_new( );
|
||||
|
||||
dh->p = BN_bin2bn( dh_P, sizeof( dh_P ), NULL );
|
||||
if( dh->p == NULL )
|
||||
|
@ -125,33 +128,39 @@ getSharedDH( void )
|
|||
if( dh->g == NULL )
|
||||
logErrorFromSSL( );
|
||||
|
||||
/* private DH value: strong random BN of DH_PRIVKEY_LEN*8 bits */
|
||||
dh->priv_key = BN_new( );
|
||||
do {
|
||||
if( BN_rand( dh->priv_key, DH_PRIVKEY_LEN * 8, -1, 0 ) != 1 )
|
||||
logErrorFromSSL( );
|
||||
} while ( BN_num_bits( dh->priv_key ) < DH_PRIVKEY_LEN_MIN * 8 );
|
||||
|
||||
if( !DH_generate_key( dh ) )
|
||||
logErrorFromSSL( );
|
||||
}
|
||||
|
||||
return dh;
|
||||
/* DH can generate key sizes that are smaller than the size of
|
||||
P with exponentially decreasing probability, in which case
|
||||
the msb's of myPublicKey need to be zeroed appropriately. */
|
||||
len = BN_num_bytes( dh->pub_key );
|
||||
offset = KEY_LEN - len;
|
||||
assert( len <= KEY_LEN );
|
||||
memset( crypto->myPublicKey, 0, offset );
|
||||
BN_bn2bin( dh->pub_key, crypto->myPublicKey + offset );
|
||||
|
||||
crypto->dh = dh;
|
||||
}
|
||||
}
|
||||
|
||||
tr_crypto *
|
||||
tr_cryptoNew( const uint8_t * torrentHash,
|
||||
int isIncoming )
|
||||
{
|
||||
int len, offset;
|
||||
tr_crypto * crypto;
|
||||
DH * dh = getSharedDH( );
|
||||
|
||||
crypto = tr_new0( tr_crypto, 1 );
|
||||
crypto->isIncoming = isIncoming ? 1 : 0;
|
||||
tr_cryptoSetTorrentHash( crypto, torrentHash );
|
||||
|
||||
/* DH can generate key sizes that are smaller than the size of
|
||||
P with exponentially decreasing probability, in which case
|
||||
the msb's of myPublicKey need to be zeroed appropriately. */
|
||||
len = DH_size( dh );
|
||||
offset = KEY_LEN - len;
|
||||
assert( len <= KEY_LEN );
|
||||
memset( crypto->myPublicKey, 0, offset );
|
||||
BN_bn2bin( dh->pub_key, crypto->myPublicKey + offset );
|
||||
crypto->dh = NULL;
|
||||
|
||||
return crypto;
|
||||
}
|
||||
|
@ -159,6 +168,8 @@ tr_cryptoNew( const uint8_t * torrentHash,
|
|||
void
|
||||
tr_cryptoFree( tr_crypto * crypto )
|
||||
{
|
||||
if( crypto->dh != NULL )
|
||||
DH_free( crypto->dh );
|
||||
tr_free( crypto );
|
||||
}
|
||||
|
||||
|
@ -173,7 +184,10 @@ tr_cryptoComputeSecret( tr_crypto * crypto,
|
|||
int len;
|
||||
uint8_t secret[KEY_LEN];
|
||||
BIGNUM * bn = BN_bin2bn( peerPublicKey, KEY_LEN, NULL );
|
||||
DH * dh = getSharedDH( );
|
||||
DH * dh;
|
||||
|
||||
ensureKeyExists( crypto );
|
||||
dh = crypto->dh;
|
||||
|
||||
assert( DH_size( dh ) == KEY_LEN );
|
||||
|
||||
|
@ -197,6 +211,7 @@ const uint8_t*
|
|||
tr_cryptoGetMyPublicKey( const tr_crypto * crypto,
|
||||
int * setme_len )
|
||||
{
|
||||
ensureKeyExists( (tr_crypto *) crypto );
|
||||
*setme_len = KEY_LEN;
|
||||
return crypto->myPublicKey;
|
||||
}
|
||||
|
|
Loading…
Reference in a new issue