| /* |
| * Elliptic curve Diffie-Hellman |
| * |
| * Copyright The Mbed TLS Contributors |
| * SPDX-License-Identifier: Apache-2.0 |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may |
| * not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| /* |
| * References: |
| * |
| * SEC1 http://www.secg.org/index.php?action=secg,docs_secg |
| * RFC 4492 |
| */ |
| |
| #include "common.h" |
| |
| #if defined(MBEDTLS_ECDH_C) |
| |
| #include "mbedtls/ecdh.h" |
| #include "mbedtls/platform_util.h" |
| #include "mbedtls/error.h" |
| |
| #include <string.h> |
| |
| /* Parameter validation macros based on platform_util.h */ |
| #define ECDH_VALIDATE_RET( cond ) \ |
| MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_ECP_BAD_INPUT_DATA ) |
| #define ECDH_VALIDATE( cond ) \ |
| MBEDTLS_INTERNAL_VALIDATE( cond ) |
| |
| #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) |
| typedef mbedtls_ecdh_context mbedtls_ecdh_context_mbed; |
| #endif |
| |
| static mbedtls_ecp_group_id mbedtls_ecdh_grp_id( |
| const mbedtls_ecdh_context *ctx ) |
| { |
| #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) |
| return( ctx->grp.id ); |
| #else |
| return( ctx->grp_id ); |
| #endif |
| } |
| |
| int mbedtls_ecdh_can_do( mbedtls_ecp_group_id gid ) |
| { |
| /* At this time, all groups support ECDH. */ |
| (void) gid; |
| return( 1 ); |
| } |
| |
| #if !defined(MBEDTLS_ECDH_GEN_PUBLIC_ALT) |
| /* |
| * Generate public key (restartable version) |
| * |
| * Note: this internal function relies on its caller preserving the value of |
| * the output parameter 'd' across continuation calls. This would not be |
| * acceptable for a public function but is OK here as we control call sites. |
| */ |
| static int ecdh_gen_public_restartable( mbedtls_ecp_group *grp, |
| mbedtls_mpi *d, mbedtls_ecp_point *Q, |
| int (*f_rng)(void *, unsigned char *, size_t), |
| void *p_rng, |
| mbedtls_ecp_restart_ctx *rs_ctx ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| /* If multiplication is in progress, we already generated a privkey */ |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| if( rs_ctx == NULL || rs_ctx->rsm == NULL ) |
| #endif |
| MBEDTLS_MPI_CHK( mbedtls_ecp_gen_privkey( grp, d, f_rng, p_rng ) ); |
| |
| MBEDTLS_MPI_CHK( mbedtls_ecp_mul_restartable( grp, Q, d, &grp->G, |
| f_rng, p_rng, rs_ctx ) ); |
| |
| cleanup: |
| return( ret ); |
| } |
| |
| /* |
| * Generate public key |
| */ |
| int mbedtls_ecdh_gen_public( mbedtls_ecp_group *grp, mbedtls_mpi *d, mbedtls_ecp_point *Q, |
| int (*f_rng)(void *, unsigned char *, size_t), |
| void *p_rng ) |
| { |
| ECDH_VALIDATE_RET( grp != NULL ); |
| ECDH_VALIDATE_RET( d != NULL ); |
| ECDH_VALIDATE_RET( Q != NULL ); |
| ECDH_VALIDATE_RET( f_rng != NULL ); |
| return( ecdh_gen_public_restartable( grp, d, Q, f_rng, p_rng, NULL ) ); |
| } |
| #endif /* !MBEDTLS_ECDH_GEN_PUBLIC_ALT */ |
| |
| #if !defined(MBEDTLS_ECDH_COMPUTE_SHARED_ALT) |
| /* |
| * Compute shared secret (SEC1 3.3.1) |
| */ |
| static int ecdh_compute_shared_restartable( mbedtls_ecp_group *grp, |
| mbedtls_mpi *z, |
| const mbedtls_ecp_point *Q, const mbedtls_mpi *d, |
| int (*f_rng)(void *, unsigned char *, size_t), |
| void *p_rng, |
| mbedtls_ecp_restart_ctx *rs_ctx ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| mbedtls_ecp_point P; |
| |
| mbedtls_ecp_point_init( &P ); |
| |
| MBEDTLS_MPI_CHK( mbedtls_ecp_mul_restartable( grp, &P, d, Q, |
| f_rng, p_rng, rs_ctx ) ); |
| |
| if( mbedtls_ecp_is_zero( &P ) ) |
| { |
| ret = MBEDTLS_ERR_ECP_BAD_INPUT_DATA; |
| goto cleanup; |
| } |
| |
| MBEDTLS_MPI_CHK( mbedtls_mpi_copy( z, &P.X ) ); |
| |
| cleanup: |
| mbedtls_ecp_point_free( &P ); |
| |
| return( ret ); |
| } |
| |
| /* |
| * Compute shared secret (SEC1 3.3.1) |
| */ |
| int mbedtls_ecdh_compute_shared( mbedtls_ecp_group *grp, mbedtls_mpi *z, |
| const mbedtls_ecp_point *Q, const mbedtls_mpi *d, |
| int (*f_rng)(void *, unsigned char *, size_t), |
| void *p_rng ) |
| { |
| ECDH_VALIDATE_RET( grp != NULL ); |
| ECDH_VALIDATE_RET( Q != NULL ); |
| ECDH_VALIDATE_RET( d != NULL ); |
| ECDH_VALIDATE_RET( z != NULL ); |
| return( ecdh_compute_shared_restartable( grp, z, Q, d, |
| f_rng, p_rng, NULL ) ); |
| } |
| #endif /* !MBEDTLS_ECDH_COMPUTE_SHARED_ALT */ |
| |
| static void ecdh_init_internal( mbedtls_ecdh_context_mbed *ctx ) |
| { |
| mbedtls_ecp_group_init( &ctx->grp ); |
| mbedtls_mpi_init( &ctx->d ); |
| mbedtls_ecp_point_init( &ctx->Q ); |
| mbedtls_ecp_point_init( &ctx->Qp ); |
| mbedtls_mpi_init( &ctx->z ); |
| |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| mbedtls_ecp_restart_init( &ctx->rs ); |
| #endif |
| } |
| |
| /* |
| * Initialize context |
| */ |
| void mbedtls_ecdh_init( mbedtls_ecdh_context *ctx ) |
| { |
| ECDH_VALIDATE( ctx != NULL ); |
| |
| #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) |
| ecdh_init_internal( ctx ); |
| mbedtls_ecp_point_init( &ctx->Vi ); |
| mbedtls_ecp_point_init( &ctx->Vf ); |
| mbedtls_mpi_init( &ctx->_d ); |
| #else |
| memset( ctx, 0, sizeof( mbedtls_ecdh_context ) ); |
| |
| ctx->var = MBEDTLS_ECDH_VARIANT_NONE; |
| #endif |
| ctx->point_format = MBEDTLS_ECP_PF_UNCOMPRESSED; |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| ctx->restart_enabled = 0; |
| #endif |
| } |
| |
| static int ecdh_setup_internal( mbedtls_ecdh_context_mbed *ctx, |
| mbedtls_ecp_group_id grp_id ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| ret = mbedtls_ecp_group_load( &ctx->grp, grp_id ); |
| if( ret != 0 ) |
| { |
| return( MBEDTLS_ERR_ECP_FEATURE_UNAVAILABLE ); |
| } |
| |
| return( 0 ); |
| } |
| |
| /* |
| * Setup context |
| */ |
| int mbedtls_ecdh_setup( mbedtls_ecdh_context *ctx, mbedtls_ecp_group_id grp_id ) |
| { |
| ECDH_VALIDATE_RET( ctx != NULL ); |
| |
| #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) |
| return( ecdh_setup_internal( ctx, grp_id ) ); |
| #else |
| switch( grp_id ) |
| { |
| #if defined(MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED) |
| case MBEDTLS_ECP_DP_CURVE25519: |
| ctx->point_format = MBEDTLS_ECP_PF_COMPRESSED; |
| ctx->var = MBEDTLS_ECDH_VARIANT_EVEREST; |
| ctx->grp_id = grp_id; |
| return( mbedtls_everest_setup( &ctx->ctx.everest_ecdh, grp_id ) ); |
| #endif |
| default: |
| ctx->point_format = MBEDTLS_ECP_PF_UNCOMPRESSED; |
| ctx->var = MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0; |
| ctx->grp_id = grp_id; |
| ecdh_init_internal( &ctx->ctx.mbed_ecdh ); |
| return( ecdh_setup_internal( &ctx->ctx.mbed_ecdh, grp_id ) ); |
| } |
| #endif |
| } |
| |
| static void ecdh_free_internal( mbedtls_ecdh_context_mbed *ctx ) |
| { |
| mbedtls_ecp_group_free( &ctx->grp ); |
| mbedtls_mpi_free( &ctx->d ); |
| mbedtls_ecp_point_free( &ctx->Q ); |
| mbedtls_ecp_point_free( &ctx->Qp ); |
| mbedtls_mpi_free( &ctx->z ); |
| |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| mbedtls_ecp_restart_free( &ctx->rs ); |
| #endif |
| } |
| |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| /* |
| * Enable restartable operations for context |
| */ |
| void mbedtls_ecdh_enable_restart( mbedtls_ecdh_context *ctx ) |
| { |
| ECDH_VALIDATE( ctx != NULL ); |
| |
| ctx->restart_enabled = 1; |
| } |
| #endif |
| |
| /* |
| * Free context |
| */ |
| void mbedtls_ecdh_free( mbedtls_ecdh_context *ctx ) |
| { |
| if( ctx == NULL ) |
| return; |
| |
| #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) |
| mbedtls_ecp_point_free( &ctx->Vi ); |
| mbedtls_ecp_point_free( &ctx->Vf ); |
| mbedtls_mpi_free( &ctx->_d ); |
| ecdh_free_internal( ctx ); |
| #else |
| switch( ctx->var ) |
| { |
| #if defined(MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED) |
| case MBEDTLS_ECDH_VARIANT_EVEREST: |
| mbedtls_everest_free( &ctx->ctx.everest_ecdh ); |
| break; |
| #endif |
| case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: |
| ecdh_free_internal( &ctx->ctx.mbed_ecdh ); |
| break; |
| default: |
| break; |
| } |
| |
| ctx->point_format = MBEDTLS_ECP_PF_UNCOMPRESSED; |
| ctx->var = MBEDTLS_ECDH_VARIANT_NONE; |
| ctx->grp_id = MBEDTLS_ECP_DP_NONE; |
| #endif |
| } |
| |
| static int ecdh_make_params_internal( mbedtls_ecdh_context_mbed *ctx, |
| size_t *olen, int point_format, |
| unsigned char *buf, size_t blen, |
| int (*f_rng)(void *, |
| unsigned char *, |
| size_t), |
| void *p_rng, |
| int restart_enabled ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| size_t grp_len, pt_len; |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| mbedtls_ecp_restart_ctx *rs_ctx = NULL; |
| #endif |
| |
| if( ctx->grp.pbits == 0 ) |
| return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); |
| |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| if( restart_enabled ) |
| rs_ctx = &ctx->rs; |
| #else |
| (void) restart_enabled; |
| #endif |
| |
| |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| if( ( ret = ecdh_gen_public_restartable( &ctx->grp, &ctx->d, &ctx->Q, |
| f_rng, p_rng, rs_ctx ) ) != 0 ) |
| return( ret ); |
| #else |
| if( ( ret = mbedtls_ecdh_gen_public( &ctx->grp, &ctx->d, &ctx->Q, |
| f_rng, p_rng ) ) != 0 ) |
| return( ret ); |
| #endif /* MBEDTLS_ECP_RESTARTABLE */ |
| |
| if( ( ret = mbedtls_ecp_tls_write_group( &ctx->grp, &grp_len, buf, |
| blen ) ) != 0 ) |
| return( ret ); |
| |
| buf += grp_len; |
| blen -= grp_len; |
| |
| if( ( ret = mbedtls_ecp_tls_write_point( &ctx->grp, &ctx->Q, point_format, |
| &pt_len, buf, blen ) ) != 0 ) |
| return( ret ); |
| |
| *olen = grp_len + pt_len; |
| return( 0 ); |
| } |
| |
| /* |
| * Setup and write the ServerKeyExchange parameters (RFC 4492) |
| * struct { |
| * ECParameters curve_params; |
| * ECPoint public; |
| * } ServerECDHParams; |
| */ |
| int mbedtls_ecdh_make_params( mbedtls_ecdh_context *ctx, size_t *olen, |
| unsigned char *buf, size_t blen, |
| int (*f_rng)(void *, unsigned char *, size_t), |
| void *p_rng ) |
| { |
| int restart_enabled = 0; |
| ECDH_VALIDATE_RET( ctx != NULL ); |
| ECDH_VALIDATE_RET( olen != NULL ); |
| ECDH_VALIDATE_RET( buf != NULL ); |
| ECDH_VALIDATE_RET( f_rng != NULL ); |
| |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| restart_enabled = ctx->restart_enabled; |
| #else |
| (void) restart_enabled; |
| #endif |
| |
| #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) |
| return( ecdh_make_params_internal( ctx, olen, ctx->point_format, buf, blen, |
| f_rng, p_rng, restart_enabled ) ); |
| #else |
| switch( ctx->var ) |
| { |
| #if defined(MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED) |
| case MBEDTLS_ECDH_VARIANT_EVEREST: |
| return( mbedtls_everest_make_params( &ctx->ctx.everest_ecdh, olen, |
| buf, blen, f_rng, p_rng ) ); |
| #endif |
| case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: |
| return( ecdh_make_params_internal( &ctx->ctx.mbed_ecdh, olen, |
| ctx->point_format, buf, blen, |
| f_rng, p_rng, |
| restart_enabled ) ); |
| default: |
| return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; |
| } |
| #endif |
| } |
| |
| static int ecdh_read_params_internal( mbedtls_ecdh_context_mbed *ctx, |
| const unsigned char **buf, |
| const unsigned char *end ) |
| { |
| return( mbedtls_ecp_tls_read_point( &ctx->grp, &ctx->Qp, buf, |
| end - *buf ) ); |
| } |
| |
| /* |
| * Read the ServerKeyExchange parameters (RFC 4492) |
| * struct { |
| * ECParameters curve_params; |
| * ECPoint public; |
| * } ServerECDHParams; |
| */ |
| int mbedtls_ecdh_read_params( mbedtls_ecdh_context *ctx, |
| const unsigned char **buf, |
| const unsigned char *end ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| mbedtls_ecp_group_id grp_id; |
| ECDH_VALIDATE_RET( ctx != NULL ); |
| ECDH_VALIDATE_RET( buf != NULL ); |
| ECDH_VALIDATE_RET( *buf != NULL ); |
| ECDH_VALIDATE_RET( end != NULL ); |
| |
| if( ( ret = mbedtls_ecp_tls_read_group_id( &grp_id, buf, end - *buf ) ) |
| != 0 ) |
| return( ret ); |
| |
| if( ( ret = mbedtls_ecdh_setup( ctx, grp_id ) ) != 0 ) |
| return( ret ); |
| |
| #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) |
| return( ecdh_read_params_internal( ctx, buf, end ) ); |
| #else |
| switch( ctx->var ) |
| { |
| #if defined(MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED) |
| case MBEDTLS_ECDH_VARIANT_EVEREST: |
| return( mbedtls_everest_read_params( &ctx->ctx.everest_ecdh, |
| buf, end) ); |
| #endif |
| case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: |
| return( ecdh_read_params_internal( &ctx->ctx.mbed_ecdh, |
| buf, end ) ); |
| default: |
| return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; |
| } |
| #endif |
| } |
| |
| static int ecdh_get_params_internal( mbedtls_ecdh_context_mbed *ctx, |
| const mbedtls_ecp_keypair *key, |
| mbedtls_ecdh_side side ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| |
| /* If it's not our key, just import the public part as Qp */ |
| if( side == MBEDTLS_ECDH_THEIRS ) |
| return( mbedtls_ecp_copy( &ctx->Qp, &key->Q ) ); |
| |
| /* Our key: import public (as Q) and private parts */ |
| if( side != MBEDTLS_ECDH_OURS ) |
| return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); |
| |
| if( ( ret = mbedtls_ecp_copy( &ctx->Q, &key->Q ) ) != 0 || |
| ( ret = mbedtls_mpi_copy( &ctx->d, &key->d ) ) != 0 ) |
| return( ret ); |
| |
| return( 0 ); |
| } |
| |
| /* |
| * Get parameters from a keypair |
| */ |
| int mbedtls_ecdh_get_params( mbedtls_ecdh_context *ctx, |
| const mbedtls_ecp_keypair *key, |
| mbedtls_ecdh_side side ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| ECDH_VALIDATE_RET( ctx != NULL ); |
| ECDH_VALIDATE_RET( key != NULL ); |
| ECDH_VALIDATE_RET( side == MBEDTLS_ECDH_OURS || |
| side == MBEDTLS_ECDH_THEIRS ); |
| |
| if( mbedtls_ecdh_grp_id( ctx ) == MBEDTLS_ECP_DP_NONE ) |
| { |
| /* This is the first call to get_params(). Set up the context |
| * for use with the group. */ |
| if( ( ret = mbedtls_ecdh_setup( ctx, key->grp.id ) ) != 0 ) |
| return( ret ); |
| } |
| else |
| { |
| /* This is not the first call to get_params(). Check that the |
| * current key's group is the same as the context's, which was set |
| * from the first key's group. */ |
| if( mbedtls_ecdh_grp_id( ctx ) != key->grp.id ) |
| return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); |
| } |
| |
| #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) |
| return( ecdh_get_params_internal( ctx, key, side ) ); |
| #else |
| switch( ctx->var ) |
| { |
| #if defined(MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED) |
| case MBEDTLS_ECDH_VARIANT_EVEREST: |
| { |
| mbedtls_everest_ecdh_side s = side == MBEDTLS_ECDH_OURS ? |
| MBEDTLS_EVEREST_ECDH_OURS : |
| MBEDTLS_EVEREST_ECDH_THEIRS; |
| return( mbedtls_everest_get_params( &ctx->ctx.everest_ecdh, |
| key, s) ); |
| } |
| #endif |
| case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: |
| return( ecdh_get_params_internal( &ctx->ctx.mbed_ecdh, |
| key, side ) ); |
| default: |
| return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; |
| } |
| #endif |
| } |
| |
| static int ecdh_make_public_internal( mbedtls_ecdh_context_mbed *ctx, |
| size_t *olen, int point_format, |
| unsigned char *buf, size_t blen, |
| int (*f_rng)(void *, |
| unsigned char *, |
| size_t), |
| void *p_rng, |
| int restart_enabled ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| mbedtls_ecp_restart_ctx *rs_ctx = NULL; |
| #endif |
| |
| if( ctx->grp.pbits == 0 ) |
| return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); |
| |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| if( restart_enabled ) |
| rs_ctx = &ctx->rs; |
| #else |
| (void) restart_enabled; |
| #endif |
| |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| if( ( ret = ecdh_gen_public_restartable( &ctx->grp, &ctx->d, &ctx->Q, |
| f_rng, p_rng, rs_ctx ) ) != 0 ) |
| return( ret ); |
| #else |
| if( ( ret = mbedtls_ecdh_gen_public( &ctx->grp, &ctx->d, &ctx->Q, |
| f_rng, p_rng ) ) != 0 ) |
| return( ret ); |
| #endif /* MBEDTLS_ECP_RESTARTABLE */ |
| |
| return mbedtls_ecp_tls_write_point( &ctx->grp, &ctx->Q, point_format, olen, |
| buf, blen ); |
| } |
| |
| /* |
| * Setup and export the client public value |
| */ |
| int mbedtls_ecdh_make_public( mbedtls_ecdh_context *ctx, size_t *olen, |
| unsigned char *buf, size_t blen, |
| int (*f_rng)(void *, unsigned char *, size_t), |
| void *p_rng ) |
| { |
| int restart_enabled = 0; |
| ECDH_VALIDATE_RET( ctx != NULL ); |
| ECDH_VALIDATE_RET( olen != NULL ); |
| ECDH_VALIDATE_RET( buf != NULL ); |
| ECDH_VALIDATE_RET( f_rng != NULL ); |
| |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| restart_enabled = ctx->restart_enabled; |
| #endif |
| |
| #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) |
| return( ecdh_make_public_internal( ctx, olen, ctx->point_format, buf, blen, |
| f_rng, p_rng, restart_enabled ) ); |
| #else |
| switch( ctx->var ) |
| { |
| #if defined(MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED) |
| case MBEDTLS_ECDH_VARIANT_EVEREST: |
| return( mbedtls_everest_make_public( &ctx->ctx.everest_ecdh, olen, |
| buf, blen, f_rng, p_rng ) ); |
| #endif |
| case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: |
| return( ecdh_make_public_internal( &ctx->ctx.mbed_ecdh, olen, |
| ctx->point_format, buf, blen, |
| f_rng, p_rng, |
| restart_enabled ) ); |
| default: |
| return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; |
| } |
| #endif |
| } |
| |
| static int ecdh_read_public_internal( mbedtls_ecdh_context_mbed *ctx, |
| const unsigned char *buf, size_t blen ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| const unsigned char *p = buf; |
| |
| if( ( ret = mbedtls_ecp_tls_read_point( &ctx->grp, &ctx->Qp, &p, |
| blen ) ) != 0 ) |
| return( ret ); |
| |
| if( (size_t)( p - buf ) != blen ) |
| return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); |
| |
| return( 0 ); |
| } |
| |
| /* |
| * Parse and import the client's public value |
| */ |
| int mbedtls_ecdh_read_public( mbedtls_ecdh_context *ctx, |
| const unsigned char *buf, size_t blen ) |
| { |
| ECDH_VALIDATE_RET( ctx != NULL ); |
| ECDH_VALIDATE_RET( buf != NULL ); |
| |
| #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) |
| return( ecdh_read_public_internal( ctx, buf, blen ) ); |
| #else |
| switch( ctx->var ) |
| { |
| #if defined(MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED) |
| case MBEDTLS_ECDH_VARIANT_EVEREST: |
| return( mbedtls_everest_read_public( &ctx->ctx.everest_ecdh, |
| buf, blen ) ); |
| #endif |
| case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: |
| return( ecdh_read_public_internal( &ctx->ctx.mbed_ecdh, |
| buf, blen ) ); |
| default: |
| return MBEDTLS_ERR_ECP_BAD_INPUT_DATA; |
| } |
| #endif |
| } |
| |
| static int ecdh_calc_secret_internal( mbedtls_ecdh_context_mbed *ctx, |
| size_t *olen, unsigned char *buf, |
| size_t blen, |
| int (*f_rng)(void *, |
| unsigned char *, |
| size_t), |
| void *p_rng, |
| int restart_enabled ) |
| { |
| int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| mbedtls_ecp_restart_ctx *rs_ctx = NULL; |
| #endif |
| |
| if( ctx == NULL || ctx->grp.pbits == 0 ) |
| return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); |
| |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| if( restart_enabled ) |
| rs_ctx = &ctx->rs; |
| #else |
| (void) restart_enabled; |
| #endif |
| |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| if( ( ret = ecdh_compute_shared_restartable( &ctx->grp, &ctx->z, &ctx->Qp, |
| &ctx->d, f_rng, p_rng, |
| rs_ctx ) ) != 0 ) |
| { |
| return( ret ); |
| } |
| #else |
| if( ( ret = mbedtls_ecdh_compute_shared( &ctx->grp, &ctx->z, &ctx->Qp, |
| &ctx->d, f_rng, p_rng ) ) != 0 ) |
| { |
| return( ret ); |
| } |
| #endif /* MBEDTLS_ECP_RESTARTABLE */ |
| |
| if( mbedtls_mpi_size( &ctx->z ) > blen ) |
| return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); |
| |
| *olen = ctx->grp.pbits / 8 + ( ( ctx->grp.pbits % 8 ) != 0 ); |
| |
| if( mbedtls_ecp_get_type( &ctx->grp ) == MBEDTLS_ECP_TYPE_MONTGOMERY ) |
| return mbedtls_mpi_write_binary_le( &ctx->z, buf, *olen ); |
| |
| return mbedtls_mpi_write_binary( &ctx->z, buf, *olen ); |
| } |
| |
| /* |
| * Derive and export the shared secret |
| */ |
| int mbedtls_ecdh_calc_secret( mbedtls_ecdh_context *ctx, size_t *olen, |
| unsigned char *buf, size_t blen, |
| int (*f_rng)(void *, unsigned char *, size_t), |
| void *p_rng ) |
| { |
| int restart_enabled = 0; |
| ECDH_VALIDATE_RET( ctx != NULL ); |
| ECDH_VALIDATE_RET( olen != NULL ); |
| ECDH_VALIDATE_RET( buf != NULL ); |
| |
| #if defined(MBEDTLS_ECP_RESTARTABLE) |
| restart_enabled = ctx->restart_enabled; |
| #endif |
| |
| #if defined(MBEDTLS_ECDH_LEGACY_CONTEXT) |
| return( ecdh_calc_secret_internal( ctx, olen, buf, blen, f_rng, p_rng, |
| restart_enabled ) ); |
| #else |
| switch( ctx->var ) |
| { |
| #if defined(MBEDTLS_ECDH_VARIANT_EVEREST_ENABLED) |
| case MBEDTLS_ECDH_VARIANT_EVEREST: |
| return( mbedtls_everest_calc_secret( &ctx->ctx.everest_ecdh, olen, |
| buf, blen, f_rng, p_rng ) ); |
| #endif |
| case MBEDTLS_ECDH_VARIANT_MBEDTLS_2_0: |
| return( ecdh_calc_secret_internal( &ctx->ctx.mbed_ecdh, olen, buf, |
| blen, f_rng, p_rng, |
| restart_enabled ) ); |
| default: |
| return( MBEDTLS_ERR_ECP_BAD_INPUT_DATA ); |
| } |
| #endif |
| } |
| #endif /* MBEDTLS_ECDH_C */ |
