Commit ab24010b authored by Manuel Pégourié-Gonnard's avatar Manuel Pégourié-Gonnard
Browse files

Enforce our choice of allowed curves.

parent 7f38ed0b
......@@ -1168,7 +1168,10 @@ int ssl_set_dh_param_ctx( ssl_context *ssl, dhm_context *dhm_ctx );
* list of available certificates instead.
*
* On client: this affects the list of curves offered for any
* use. The server can override our preferences.
* use. The server can override our preference order.
*
* Both sides: limits the set of curves used by peer to the
* listed curves for any use (ECDH(E), certificates).
*
* \param ssl SSL context
* \param curves Ordered list of allowed curves,
......@@ -1589,6 +1592,10 @@ pk_type_t ssl_pk_alg_from_sig( unsigned char sig );
md_type_t ssl_md_alg_from_hash( unsigned char hash );
#if defined(POLARSSL_SSL_SET_CURVES)
int ssl_curve_is_acceptable( const ssl_context *ssl, ecp_group_id grp_id );
#endif
#if defined(POLARSSL_X509_CRT_PARSE_C)
static inline pk_context *ssl_own_key( ssl_context *ssl )
{
......
......@@ -1125,14 +1125,17 @@ static int ssl_parse_server_dh_params( ssl_context *ssl, unsigned char **p,
defined(POLARSSL_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
static int ssl_check_server_ecdh_params( const ssl_context *ssl )
{
// TODO: print name instead
SSL_DEBUG_MSG( 2, ( "ECDH curve size: %d",
(int) ssl->handshake->ecdh_ctx.grp.nbits ) );
#if defined(POLARSSL_SSL_ECP_SET_CURVES)
if( ! ssl_curve_is_acceptable( ssl, ssl->handshake->ecdh_ctx.grp.id ) )
#else
if( ssl->handshake->ecdh_ctx.grp.nbits < 163 ||
ssl->handshake->ecdh_ctx.grp.nbits > 521 )
{
#endif
return( -1 );
}
SSL_DEBUG_ECP( 3, "ECDH: Qp", &ssl->handshake->ecdh_ctx.Qp );
......@@ -1167,7 +1170,7 @@ static int ssl_parse_server_ecdh_params( ssl_context *ssl,
if( ssl_check_server_ecdh_params( ssl ) != 0 )
{
SSL_DEBUG_MSG( 1, ( "bad server key exchange message (ECDH length)" ) );
SSL_DEBUG_MSG( 1, ( "bad server key exchange message (ECDHE curve)" ) );
return( POLARSSL_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
}
......@@ -1355,7 +1358,7 @@ static int ssl_get_ecdh_params_from_cert( ssl_context *ssl )
if( ssl_check_server_ecdh_params( ssl ) != 0 )
{
SSL_DEBUG_MSG( 1, ( "bad server certificate (ECDH length)" ) );
SSL_DEBUG_MSG( 1, ( "bad server certificate (ECDH curve)" ) );
return( POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE );
}
......@@ -1397,7 +1400,11 @@ static int ssl_parse_server_key_exchange( ssl_context *ssl )
if( ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDH_RSA ||
ciphersuite_info->key_exchange == POLARSSL_KEY_EXCHANGE_ECDH_ECDSA )
{
ssl_get_ecdh_params_from_cert( ssl );
if( ( ret = ssl_get_ecdh_params_from_cert( ssl ) ) != 0 )
{
SSL_DEBUG_RET( 1, "ssl_get_ecdh_params_from_cert", ret );
return( ret );
}
SSL_DEBUG_MSG( 2, ( "<= skip parse server key exchange" ) );
ssl->state++;
......
......@@ -2664,7 +2664,23 @@ int ssl_parse_certificate( ssl_context *ssl )
ssl->f_vrfy, ssl->p_vrfy );
if( ret != 0 )
{
SSL_DEBUG_RET( 1, "x509_verify_cert", ret );
}
#if defined(POLARSSL_SSL_SET_CURVES)
else
{
pk_context *pk = &ssl->session_negotiate->peer_cert->pk;
/* If certificate uses an EC key, make sure the curve is OK */
if( pk_can_do( pk, POLARSSL_PK_ECKEY ) &&
! ssl_curve_is_acceptable( ssl, pk_ec( *pk )->grp.id ) )
{
SSL_DEBUG_MSG( 1, ( "bad server certificate (EC key curve)" ) );
ret = POLARSSL_ERR_SSL_BAD_HS_CERTIFICATE;
}
}
#endif
if( ssl->authmode != SSL_VERIFY_REQUIRED )
ret = 0;
......@@ -4625,3 +4641,19 @@ md_type_t ssl_md_alg_from_hash( unsigned char hash )
#endif
#if defined(POLARSSL_SSL_SET_CURVES)
/*
* Check is a curve proposed by the peer is in our list.
* Return 1 if we're willing to use it, 0 otherwise.
*/
int ssl_curve_is_acceptable( const ssl_context *ssl, ecp_group_id grp_id )
{
const ecp_group_id *gid;
for( gid = ssl->curve_list; *gid != POLARSSL_ECP_DP_NONE; gid++ )
if( *gid == grp_id )
return( 1 );
return( 0 );
}
#endif
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