Reduce indentation in ssl_compute_master()

Exit earlier when there's noting to do.

For a small diff, review with 'git show -w'.
This commit is contained in:
Manuel Pégourié-Gonnard 2019-05-03 09:16:16 +02:00 committed by Jarno Lamsa
parent 9951b712bd
commit 85680c49ef

View file

@ -1578,7 +1578,7 @@ static int ssl_set_handshake_prfs( mbedtls_ssl_handshake_params *handshake,
}
/*
* Compute master secret
* Compute master secret if needed
*/
static int ssl_compute_master( mbedtls_ssl_context *ssl )
{
@ -1595,134 +1595,123 @@ static int ssl_compute_master( mbedtls_ssl_context *ssl )
unsigned char session_hash[48];
#endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
/*
* SSLv3:
* master =
* MD5( premaster + SHA1( 'A' + premaster + randbytes ) ) +
* MD5( premaster + SHA1( 'BB' + premaster + randbytes ) ) +
* MD5( premaster + SHA1( 'CCC' + premaster + randbytes ) )
*
* TLSv1+:
* master = PRF( premaster, "master secret", randbytes )[0..47]
*/
/* The label for the KDF used for key expansion.
* This is either "master secret" or "extended master secret"
* depending on whether the Extended Master Secret extension
* is used. */
char const *lbl = "master secret";
/* The salt for the KDF used for key expansion.
* - If the Extended Master Secret extension is not used,
* this is ClientHello.Random + ServerHello.Random
* (see Sect. 8.1 in RFC 5246).
* - If the Extended Master Secret extension is used,
* this is the transcript of the handshake so far.
* (see Sect. 4 in RFC 7627). */
unsigned char const *salt = handshake->randbytes;
size_t salt_len = 64;
if( handshake->resume != 0 )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "no premaster (session resumed)" ) );
return( 0 );
}
else
{
/* The label for the KDF used for key expansion.
* This is either "master secret" or "extended master secret"
* depending on whether the Extended Master Secret extension
* is used. */
char const *lbl = "master secret";
/* The salt for the KDF used for key expansion.
* - If the Extended Master Secret extension is not used,
* this is ClientHello.Random + ServerHello.Random
* (see Sect. 8.1 in RFC 5246).
* - If the Extended Master Secret extension is used,
* this is the transcript of the handshake so far.
* (see Sect. 4 in RFC 7627). */
unsigned char const *salt = handshake->randbytes;
size_t salt_len = 64;
#if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
if( ssl->handshake->extended_ms == MBEDTLS_SSL_EXTENDED_MS_ENABLED )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "using extended master secret" ) );
if( ssl->handshake->extended_ms == MBEDTLS_SSL_EXTENDED_MS_ENABLED )
{
MBEDTLS_SSL_DEBUG_MSG( 3, ( "using extended master secret" ) );
lbl = "extended master secret";
salt = session_hash;
ssl->handshake->calc_verify( ssl, session_hash );
lbl = "extended master secret";
salt = session_hash;
ssl->handshake->calc_verify( ssl, session_hash );
#if defined(MBEDTLS_SSL_PROTO_TLS1_2)
if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
{
if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 )
{
#if defined(MBEDTLS_SHA512_C)
if( ciphersuite_info->mac == MBEDTLS_MD_SHA384 )
{
salt_len = 48;
}
else
#endif /* MBEDTLS_SHA512_C */
salt_len = 32;
if( ciphersuite_info->mac == MBEDTLS_MD_SHA384 )
{
salt_len = 48;
}
else
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
salt_len = 36;
MBEDTLS_SSL_DEBUG_BUF( 3, "session hash", session_hash, salt_len );
#endif /* MBEDTLS_SHA512_C */
salt_len = 32;
}
else
#endif /* MBEDTLS_SSL_PROTO_TLS1_2 */
salt_len = 36;
MBEDTLS_SSL_DEBUG_BUF( 3, "session hash", session_hash, salt_len );
}
#endif /* MBEDTLS_SSL_EXTENDED_MS_ENABLED */
#if defined(MBEDTLS_USE_PSA_CRYPTO) && \
defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK &&
ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 &&
ssl_use_opaque_psk( ssl ) == 1 )
{
/* Perform PSK-to-MS expansion in a single step. */
psa_status_t status;
psa_algorithm_t alg;
psa_key_handle_t psk;
psa_key_derivation_operation_t derivation =
PSA_KEY_DERIVATION_OPERATION_INIT;
defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
if( ciphersuite_info->key_exchange == MBEDTLS_KEY_EXCHANGE_PSK &&
ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_3 &&
ssl_use_opaque_psk( ssl ) == 1 )
{
/* Perform PSK-to-MS expansion in a single step. */
psa_status_t status;
psa_algorithm_t alg;
psa_key_handle_t psk;
psa_key_derivation_operation_t derivation =
PSA_KEY_DERIVATION_OPERATION_INIT;
MBEDTLS_SSL_DEBUG_MSG( 2, ( "perform PSA-based PSK-to-MS expansion" ) );
MBEDTLS_SSL_DEBUG_MSG( 2, ( "perform PSA-based PSK-to-MS expansion" ) );
psk = ssl->conf->psk_opaque;
if( ssl->handshake->psk_opaque != 0 )
psk = ssl->handshake->psk_opaque;
psk = ssl->conf->psk_opaque;
if( ssl->handshake->psk_opaque != 0 )
psk = ssl->handshake->psk_opaque;
if( ciphersuite_info->mac == MBEDTLS_MD_SHA384 )
alg = PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_384);
else
alg = PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_256);
status = psa_key_derivation( &derivation, psk, alg,
salt, salt_len,
(unsigned char const *) lbl,
(size_t) strlen( lbl ),
master_secret_len );
if( status != PSA_SUCCESS )
{
psa_key_derivation_abort( &derivation );
return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
}
status = psa_key_derivation_output_bytes( &derivation,
session->master,
master_secret_len );
if( status != PSA_SUCCESS )
{
psa_key_derivation_abort( &derivation );
return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
}
status = psa_key_derivation_abort( &derivation );
if( status != PSA_SUCCESS )
return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
}
if( ciphersuite_info->mac == MBEDTLS_MD_SHA384 )
alg = PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_384);
else
#endif
alg = PSA_ALG_TLS12_PSK_TO_MS(PSA_ALG_SHA_256);
status = psa_key_derivation( &derivation, psk, alg,
salt, salt_len,
(unsigned char const *) lbl,
(size_t) strlen( lbl ),
master_secret_len );
if( status != PSA_SUCCESS )
{
ret = handshake->tls_prf( handshake->premaster, handshake->pmslen,
lbl, salt, salt_len,
session->master,
master_secret_len );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "prf", ret );
return( ret );
}
MBEDTLS_SSL_DEBUG_BUF( 3, "premaster secret",
handshake->premaster,
handshake->pmslen );
mbedtls_platform_zeroize( handshake->premaster,
sizeof(handshake->premaster) );
psa_key_derivation_abort( &derivation );
return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
}
status = psa_key_derivation_output_bytes( &derivation,
session->master,
master_secret_len );
if( status != PSA_SUCCESS )
{
psa_key_derivation_abort( &derivation );
return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
}
status = psa_key_derivation_abort( &derivation );
if( status != PSA_SUCCESS )
return( MBEDTLS_ERR_SSL_HW_ACCEL_FAILED );
}
else
#endif
{
ret = handshake->tls_prf( handshake->premaster, handshake->pmslen,
lbl, salt, salt_len,
session->master,
master_secret_len );
if( ret != 0 )
{
MBEDTLS_SSL_DEBUG_RET( 1, "prf", ret );
return( ret );
}
MBEDTLS_SSL_DEBUG_BUF( 3, "premaster secret",
handshake->premaster,
handshake->pmslen );
mbedtls_platform_zeroize( handshake->premaster,
sizeof(handshake->premaster) );
}
return( 0 );