Add ssl_conf_dhm_min_bitlen()

parent bf27eaac
......@@ -577,6 +577,10 @@ struct mbedtls_ssl_config
unsigned int badmac_limit; /*!< limit of records with a bad MAC */
#endif
#if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_CLI_C)
unsigned int dhm_min_bitlen; /*!< min. bit length of the DHM prime */
#endif
unsigned char max_major_ver; /*!< max. major version used */
unsigned char max_minor_ver; /*!< max. minor version used */
unsigned char min_major_ver; /*!< min. major version used */
......@@ -1477,6 +1481,19 @@ int mbedtls_ssl_conf_dh_param( mbedtls_ssl_config *conf, const char *dhm_P, cons
int mbedtls_ssl_conf_dh_param_ctx( mbedtls_ssl_config *conf, mbedtls_dhm_context *dhm_ctx );
#endif /* MBEDTLS_DHM_C && defined(MBEDTLS_SSL_SRV_C) */
#if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_CLI_C)
/**
* \brief Set the minimum length for Diffie-Hellman parameters.
* (Client-side only.)
* (Default: 1024 bits.)
*
* \param conf SSL configuration
* \param bitlen Minimum bit length of the DHM prime
*/
void mbedtls_ssl_conf_dhm_min_bitlen( mbedtls_ssl_config *conf,
unsigned int bitlen );
#endif /* MBEDTLS_DHM_C && MBEDTLS_SSL_CLI_C */
#if defined(MBEDTLS_SSL_SET_CURVES)
/**
* \brief Set the allowed curves in order of preference.
......
......@@ -1648,10 +1648,11 @@ static int ssl_parse_server_dh_params( mbedtls_ssl_context *ssl, unsigned char *
return( ret );
}
if( ssl->handshake->dhm_ctx.len < 64 ||
ssl->handshake->dhm_ctx.len > 512 )
if( ssl->handshake->dhm_ctx.len * 8 < ssl->conf->dhm_min_bitlen )
{
MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad server key exchange message (DHM length)" ) );
MBEDTLS_SSL_DEBUG_MSG( 1, ( "DHM prime too short: %d < %d",
ssl->handshake->dhm_ctx.len * 8,
ssl->conf->dhm_min_bitlen ) );
return( MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE );
}
......
......@@ -5458,6 +5458,17 @@ int mbedtls_ssl_conf_dh_param_ctx( mbedtls_ssl_config *conf, mbedtls_dhm_context
}
#endif /* MBEDTLS_DHM_C && MBEDTLS_SSL_SRV_C */
#if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_CLI_C)
/*
* Set the minimum length for Diffie-Hellman parameters
*/
void mbedtls_ssl_conf_dhm_min_bitlen( mbedtls_ssl_config *conf,
unsigned int bitlen )
{
conf->dhm_min_bitlen = bitlen;
}
#endif /* MBEDTLS_DHM_C && MBEDTLS_SSL_CLI_C */
#if defined(MBEDTLS_SSL_SET_CURVES)
/*
* Set the allowed elliptic curves
......@@ -6665,6 +6676,10 @@ int mbedtls_ssl_config_defaults( mbedtls_ssl_config *conf,
conf->renego_period[7] = 0x00;
#endif
#if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_CLI_C)
conf->dhm_min_bitlen = 1024;
#endif
#if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_SRV_C)
if( endpoint == MBEDTLS_SSL_IS_SERVER )
{
......
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