mirror of
https://github.com/Mbed-TLS/mbedtls.git
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add key_share extension
Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
This commit is contained in:
Jerry Yu
parent
7236994aa9
commit
56fc07f7ae
@ -31,6 +31,7 @@
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#include "mbedtls/ecdh.h"
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#include "mbedtls/platform_util.h"
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#include "mbedtls/error.h"
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#include "ssl_misc.h"
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#include <string.h>
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@ -726,4 +727,88 @@ int mbedtls_ecdh_calc_secret( mbedtls_ecdh_context *ctx, size_t *olen,
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#endif
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}
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#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
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static int ecdh_tls13_make_params_internal( mbedtls_ecdh_context_mbed *ctx,
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size_t *olen, int point_format,
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unsigned char *buf, size_t blen,
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int ( *f_rng )( void *,
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unsigned char *,
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size_t),
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void *p_rng, int restart_enabled )
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{
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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#if defined(MBEDTLS_ECP_RESTARTABLE)
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mbedtls_ecp_restart_ctx *rs_ctx = NULL;
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#endif
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if( ctx->grp.pbits == 0 )
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return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA );
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#if defined(MBEDTLS_ECP_RESTARTABLE)
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if( restart_enabled )
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rs_ctx = &ctx->rs;
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#else
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(void) restart_enabled;
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#endif
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#if defined(MBEDTLS_ECP_RESTARTABLE)
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if( ( ret = ecdh_gen_public_restartable( &ctx->grp, &ctx->d, &ctx->Q,
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f_rng, p_rng, rs_ctx ) ) != 0 )
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return( ret );
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#else
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if( ( ret = mbedtls_ecdh_gen_public( &ctx->grp, &ctx->d, &ctx->Q,
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f_rng, p_rng ) ) != 0 )
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return( ret );
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#endif /* MBEDTLS_ECP_RESTARTABLE */
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ret = mbedtls_ecp_point_write_binary( &ctx->grp, &ctx->Q, point_format,
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olen, buf, blen );
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if( ret != 0 )
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return( ret );
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return( 0 );
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}
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int mbedtls_ecdh_tls13_make_params( mbedtls_ecdh_context *ctx, size_t *olen,
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unsigned char *buf, size_t blen,
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int ( *f_rng )( void *, unsigned char *, size_t ),
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void *p_rng )
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{
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int restart_enabled = 0;
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ECDH_VALIDATE_RET( ctx != NULL );
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ECDH_VALIDATE_RET( olen != NULL );
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ECDH_VALIDATE_RET( buf != NULL );
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ECDH_VALIDATE_RET( f_rng != NULL );
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#if defined(MBEDTLS_ECP_RESTARTABLE)
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restart_enabled = ctx->restart_enabled;
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#else
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(void) restart_enabled;
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#endif
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#if defined(MBEDTLS_ECDH_LEGACY_CONTEXT)
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return( ecdh_tls13_make_params_internal( ctx, olen, ctx->point_format, buf, blen,
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f_rng, p_rng, restart_enabled ) );
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#else
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switch( ctx->var )
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{
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#if defined(MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED)
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case MBEDTLS_ECDH_VARIANT_EVEREST:
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return( mbedtls_everest_make_params( &ctx->ctx.everest_ecdh, olen,
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buf, blen, f_rng, p_rng ) );
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#endif
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case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0:
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return( ecdh_tls13_make_params_internal( &ctx->ctx.mbed_ecdh, olen,
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ctx->point_format, buf, blen,
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f_rng, p_rng,
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restart_enabled ) );
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default:
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return MBEDTLS_ERR_ECP_BAD_INPUT_DATA;
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}
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#endif
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}
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#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
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#endif /* MBEDTLS_ECDH_C */
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@ -649,6 +649,16 @@ struct mbedtls_ssl_handshake_params
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void (*calc_finished)(mbedtls_ssl_context *, unsigned char *, int);
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mbedtls_ssl_tls_prf_cb *tls_prf;
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#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
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uint16_t offered_group_id; /* The NamedGroup value for the group
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* that is being used for ephemeral
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* key exchange.
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*
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* On the client: Defaults to the first
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* entry in the client's group list,
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* but can be overwritten by the HRR. */
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#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
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mbedtls_ssl_ciphersuite_t const *ciphersuite_info;
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size_t pmslen; /*!< premaster length */
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@ -1491,6 +1501,16 @@ int mbedtls_ssl_tls13_write_sig_alg_ext( mbedtls_ssl_context *ssl,
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unsigned char *buf,
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unsigned char *end,
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size_t *olen);
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#if defined(MBEDTLS_ECDH_C)
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/*
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* TLS 1.3 version of mbedtls_ecdh_make_params in ecdh.h
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*/
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int mbedtls_ecdh_tls13_make_params( mbedtls_ecdh_context *ctx, size_t *olen,
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unsigned char *buf, size_t blen,
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int ( *f_rng )( void *, unsigned char *, size_t ),
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void *p_rng );
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#endif /* MBEDTLS_ECDH_C */
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#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
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#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
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@ -28,7 +28,8 @@
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#include <string.h>
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#include "ssl_misc.h"
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#include <mbedtls/debug.h>
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#include "mbedtls/debug.h"
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#include "mbedtls/error.h"
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#define CLIENT_HELLO_RANDOM_LEN 32
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@ -257,24 +258,212 @@ static int ssl_tls13_write_supported_groups_ext( mbedtls_ssl_context *ssl,
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return( ret );
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}
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static int ssl_tls13_write_key_shares_ext( mbedtls_ssl_context *ssl,
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unsigned char *buf,
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unsigned char *end,
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size_t *olen )
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/*
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* Functions for writing key_share extension.
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*/
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#if defined(MBEDTLS_ECDH_C)
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static int ssl_key_share_gen_and_write_ecdhe( mbedtls_ssl_context *ssl,
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uint16_t named_group,
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unsigned char *buf,
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unsigned char *end,
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size_t *olen )
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{
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((void) ssl);
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((void) buf);
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((void) end);
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*olen = 0;
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "key share extension is not available" ) );
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int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
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const mbedtls_ecp_curve_info *curve_info =
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mbedtls_ecp_curve_info_from_tls_id( named_group );
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if( curve_info == NULL )
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return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "offer curve %s", curve_info->name ) );
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if( ( ret = mbedtls_ecdh_setup( &ssl->handshake->ecdh_ctx,
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curve_info->grp_id ) ) != 0 )
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{
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MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecp_group_load", ret );
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return( ret );
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}
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ret = mbedtls_ecdh_tls13_make_params( &ssl->handshake->ecdh_ctx, olen,
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buf, end - buf,
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ssl->conf->f_rng, ssl->conf->p_rng );
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if( ret != 0 )
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{
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MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_tls13_make_params", ret );
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return( ret );
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}
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MBEDTLS_SSL_DEBUG_ECDH( 3, &ssl->handshake->ecdh_ctx,
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MBEDTLS_DEBUG_ECDH_Q );
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return( 0 );
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}
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#endif /* MBEDTLS_ECDH_C */
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static int ssl_named_group_get_default_id( mbedtls_ssl_context *ssl,
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uint16_t *named_group_id )
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{
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int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
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/* Pick first entry of curve list.
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*
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* TODO: When we introduce PQC KEMs, we'll have a NamedGroup
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* list instead, and can just return its first element.
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*/
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/* Check if ecdhe named groups are available and pick first entry */
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#if defined(MBEDTLS_ECDH_C)
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#if !defined(MBEDTLS_ECP_C)
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((void) ssl);
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#endif
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#if defined(MBEDTLS_ECP_C)
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for ( const mbedtls_ecp_group_id * grp_id = ssl->conf->curve_list;
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*grp_id != MBEDTLS_ECP_DP_NONE;
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grp_id++ )
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{
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const mbedtls_ecp_curve_info *info;
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info = mbedtls_ecp_curve_info_from_grp_id( *grp_id );
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#else
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for ( const mbedtls_ecp_curve_info *info = mbedtls_ecp_curve_list();
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info->grp_id != MBEDTLS_ECP_DP_NONE;
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info++ )
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{
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#endif
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if( info != NULL && mbedtls_ssl_named_group_is_ecdhe( info->tls_id ) )
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{
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*named_group_id = info->tls_id;
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return( 0 );
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}
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}
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#else
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((void) ssl);
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((void) named_group_id);
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#endif /* MBEDTLS_ECDH_C */
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/*
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* Add DHE named groups here.
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* Check if ecdhe named groups are available and pick first entry
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*/
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return( ret );
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}
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/*
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* ssl_tls13_write_key_share_ext
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*
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* Structure of key_share extension in ClientHelo:
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*
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* struct {
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* NamedGroup group;
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* opaque key_exchange<1..2^16-1>;
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* } KeyShareEntry;
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* struct {
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* KeyShareEntry client_shares<0..2^16-1>;
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* } KeyShareClientHello;
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*/
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static int ssl_tls13_write_key_share_ext( mbedtls_ssl_context *ssl,
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unsigned char *buf,
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unsigned char *end,
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size_t *olen )
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{
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unsigned char *p = buf;
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unsigned char *client_shares_ptr; /* Start of client_shares */
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uint16_t group_id;
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int ret = MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE;
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*olen = 0;
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if( !mbedtls_ssl_conf_tls13_some_ephemeral_enabled( ssl ) )
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return( 0 );
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/* Check if we have space for headers and length fields:
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* - extension_type (2 bytes)
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* - extension_data_length (2 bytes)
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* - client_shares_length (2 bytes)
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*/
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MBEDTLS_SSL_CHK_BUF_PTR( p, end, 6 );
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p += 6;
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MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello: adding key share extension" ) );
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/* HRR could already have requested something else. */
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group_id = ssl->handshake->offered_group_id;
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if( !mbedtls_ssl_named_group_is_ecdhe( group_id ) &&
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!mbedtls_ssl_named_group_is_dhe( group_id ) )
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{
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MBEDTLS_SSL_PROC_CHK( ssl_named_group_get_default_id( ssl,
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&group_id ) );
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}
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/*
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* Dispatch to type-specific key generation function.
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*
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* So far, we're only supporting ECDHE. With the introduction
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* of PQC KEMs, we'll want to have multiple branches, one per
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* type of KEM, and dispatch to the corresponding crypto. And
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* only one key share entry is allowed.
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*/
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client_shares_ptr = p;
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#if defined(MBEDTLS_ECDH_C)
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if( mbedtls_ssl_named_group_is_ecdhe( group_id ) )
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{
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/* Pointer of group */
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unsigned char *group_id_ptr = p;
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/* Length of key_exchange */
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size_t key_exchange_len;
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/* Check there is space for header of KeyShareEntry
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* - group (2 bytes)
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* - key_exchange_length (2 bytes)
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*/
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MBEDTLS_SSL_CHK_BUF_PTR( p, end, 4 );
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p += 4;
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ret = ssl_key_share_gen_and_write_ecdhe( ssl, group_id,
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p, end,
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&key_exchange_len );
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p += key_exchange_len;
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if( ret != 0 )
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return( ret );
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/* Write group */
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MBEDTLS_PUT_UINT16_BE( group_id, group_id_ptr, 0 );
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/* Write key_exchange_length */
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MBEDTLS_PUT_UINT16_BE( key_exchange_len, group_id_ptr, 2 );
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}
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else
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#endif /* MBEDTLS_ECDH_C */
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if( 0 /* other KEMs? */ )
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{
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/* Do something */
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}
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else
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return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
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/* Write extension_type */
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MBEDTLS_PUT_UINT16_BE( MBEDTLS_TLS_EXT_KEY_SHARE, buf, 0 );
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/* Write extension_data_length */
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MBEDTLS_PUT_UINT16_BE( p - client_shares_ptr + 2, buf, 2 );
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/* Write client_shares_length */
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MBEDTLS_PUT_UINT16_BE( p - client_shares_ptr, buf, 4 );
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/* Update offered_group_id field */
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ssl->handshake->offered_group_id = group_id;
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/* Output the total length of key_share extension. */
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*olen = p - buf;
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MBEDTLS_SSL_DEBUG_BUF( 3, "client hello, key_share extension", buf, *olen );
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ssl->handshake->extensions_present |= MBEDTLS_SSL_EXT_KEY_SHARE;
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cleanup:
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return( ret );
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}
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#endif /* MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED */
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/*
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* Functions for writing ClientHello message.
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*/
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/* Write cipher_suites
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* CipherSuite cipher_suites<2..2^16-2>;
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*/
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@ -464,7 +653,7 @@ static int ssl_tls13_write_client_hello_body( mbedtls_ssl_context *ssl,
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* 3) Or, in case all ciphers are supported ( which includes #1 and #2
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* from above )
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*/
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ret = ssl_tls13_write_key_shares_ext( ssl, p, end, &output_len );
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ret = ssl_tls13_write_key_share_ext( ssl, p, end, &output_len );
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if( ret != 0 )
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return( ret );
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p += output_len;
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