712 lines
		
	
	
		
			20 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
		
		
			
		
	
	
			712 lines
		
	
	
		
			20 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
|  | /*
 | ||
|  |  *  Diffie-Hellman-Merkle key exchange | ||
|  |  * | ||
|  |  *  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. | ||
|  |  */ | ||
|  | /*
 | ||
|  |  *  The following sources were referenced in the design of this implementation | ||
|  |  *  of the Diffie-Hellman-Merkle algorithm: | ||
|  |  * | ||
|  |  *  [1] Handbook of Applied Cryptography - 1997, Chapter 12 | ||
|  |  *      Menezes, van Oorschot and Vanstone | ||
|  |  * | ||
|  |  */ | ||
|  | 
 | ||
|  | #include "common.h"
 | ||
|  | 
 | ||
|  | #if defined(MBEDTLS_DHM_C)
 | ||
|  | 
 | ||
|  | #include "mbedtls/dhm.h"
 | ||
|  | #include "mbedtls/platform_util.h"
 | ||
|  | #include "mbedtls/error.h"
 | ||
|  | 
 | ||
|  | #include <string.h>
 | ||
|  | 
 | ||
|  | #if defined(MBEDTLS_PEM_PARSE_C)
 | ||
|  | #include "mbedtls/pem.h"
 | ||
|  | #endif
 | ||
|  | 
 | ||
|  | #if defined(MBEDTLS_ASN1_PARSE_C)
 | ||
|  | #include "mbedtls/asn1.h"
 | ||
|  | #endif
 | ||
|  | 
 | ||
|  | #include "mbedtls/platform.h"
 | ||
|  | 
 | ||
|  | #if !defined(MBEDTLS_DHM_ALT)
 | ||
|  | 
 | ||
|  | #define DHM_VALIDATE_RET( cond )    \
 | ||
|  |     MBEDTLS_INTERNAL_VALIDATE_RET( cond, MBEDTLS_ERR_DHM_BAD_INPUT_DATA ) | ||
|  | #define DHM_VALIDATE( cond )        \
 | ||
|  |     MBEDTLS_INTERNAL_VALIDATE( cond ) | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * helper to validate the mbedtls_mpi size and import it | ||
|  |  */ | ||
|  | static int dhm_read_bignum( mbedtls_mpi *X, | ||
|  |                             unsigned char **p, | ||
|  |                             const unsigned char *end ) | ||
|  | { | ||
|  |     int ret, n; | ||
|  | 
 | ||
|  |     if( end - *p < 2 ) | ||
|  |         return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); | ||
|  | 
 | ||
|  |     n = ( (*p)[0] << 8 ) | (*p)[1]; | ||
|  |     (*p) += 2; | ||
|  | 
 | ||
|  |     if( (int)( end - *p ) < n ) | ||
|  |         return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); | ||
|  | 
 | ||
|  |     if( ( ret = mbedtls_mpi_read_binary( X, *p, n ) ) != 0 ) | ||
|  |         return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_DHM_READ_PARAMS_FAILED, ret ) ); | ||
|  | 
 | ||
|  |     (*p) += n; | ||
|  | 
 | ||
|  |     return( 0 ); | ||
|  | } | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Verify sanity of parameter with regards to P | ||
|  |  * | ||
|  |  * Parameter should be: 2 <= public_param <= P - 2 | ||
|  |  * | ||
|  |  * This means that we need to return an error if | ||
|  |  *              public_param < 2 or public_param > P-2 | ||
|  |  * | ||
|  |  * For more information on the attack, see: | ||
|  |  *  http://www.cl.cam.ac.uk/~rja14/Papers/psandqs.pdf
 | ||
|  |  *  http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2005-2643
 | ||
|  |  */ | ||
|  | static int dhm_check_range( const mbedtls_mpi *param, const mbedtls_mpi *P ) | ||
|  | { | ||
|  |     mbedtls_mpi U; | ||
|  |     int ret = 0; | ||
|  | 
 | ||
|  |     mbedtls_mpi_init( &U ); | ||
|  | 
 | ||
|  |     MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &U, P, 2 ) ); | ||
|  | 
 | ||
|  |     if( mbedtls_mpi_cmp_int( param, 2 ) < 0 || | ||
|  |         mbedtls_mpi_cmp_mpi( param, &U ) > 0 ) | ||
|  |     { | ||
|  |         ret = MBEDTLS_ERR_DHM_BAD_INPUT_DATA; | ||
|  |     } | ||
|  | 
 | ||
|  | cleanup: | ||
|  |     mbedtls_mpi_free( &U ); | ||
|  |     return( ret ); | ||
|  | } | ||
|  | 
 | ||
|  | void mbedtls_dhm_init( mbedtls_dhm_context *ctx ) | ||
|  | { | ||
|  |     DHM_VALIDATE( ctx != NULL ); | ||
|  |     memset( ctx, 0, sizeof( mbedtls_dhm_context ) ); | ||
|  | } | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Parse the ServerKeyExchange parameters | ||
|  |  */ | ||
|  | int mbedtls_dhm_read_params( mbedtls_dhm_context *ctx, | ||
|  |                      unsigned char **p, | ||
|  |                      const unsigned char *end ) | ||
|  | { | ||
|  |     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | ||
|  |     DHM_VALIDATE_RET( ctx != NULL ); | ||
|  |     DHM_VALIDATE_RET( p != NULL && *p != NULL ); | ||
|  |     DHM_VALIDATE_RET( end != NULL ); | ||
|  | 
 | ||
|  |     if( ( ret = dhm_read_bignum( &ctx->P,  p, end ) ) != 0 || | ||
|  |         ( ret = dhm_read_bignum( &ctx->G,  p, end ) ) != 0 || | ||
|  |         ( ret = dhm_read_bignum( &ctx->GY, p, end ) ) != 0 ) | ||
|  |         return( ret ); | ||
|  | 
 | ||
|  |     if( ( ret = dhm_check_range( &ctx->GY, &ctx->P ) ) != 0 ) | ||
|  |         return( ret ); | ||
|  | 
 | ||
|  |     ctx->len = mbedtls_mpi_size( &ctx->P ); | ||
|  | 
 | ||
|  |     return( 0 ); | ||
|  | } | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Pick a random R in the range [2, M-2] for blinding or key generation. | ||
|  |  */ | ||
|  | static int dhm_random_below( mbedtls_mpi *R, const mbedtls_mpi *M, | ||
|  |                 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) | ||
|  | { | ||
|  |     int ret; | ||
|  | 
 | ||
|  |     MBEDTLS_MPI_CHK( mbedtls_mpi_random( R, 3, M, f_rng, p_rng ) ); | ||
|  |     MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( R, R, 1 ) ); | ||
|  | 
 | ||
|  | cleanup: | ||
|  |     return( ret ); | ||
|  | } | ||
|  | 
 | ||
|  | static int dhm_make_common( mbedtls_dhm_context *ctx, int x_size, | ||
|  |                             int (*f_rng)(void *, unsigned char *, size_t), | ||
|  |                             void *p_rng ) | ||
|  | { | ||
|  |     int ret = 0; | ||
|  | 
 | ||
|  |     if( mbedtls_mpi_cmp_int( &ctx->P, 0 ) == 0 ) | ||
|  |         return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); | ||
|  |     if( x_size < 0 ) | ||
|  |         return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); | ||
|  | 
 | ||
|  |     if( (unsigned) x_size < mbedtls_mpi_size( &ctx->P ) ) | ||
|  |     { | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng ) ); | ||
|  |     } | ||
|  |     else | ||
|  |     { | ||
|  |         /* Generate X as large as possible ( <= P - 2 ) */ | ||
|  |         ret = dhm_random_below( &ctx->X, &ctx->P, f_rng, p_rng ); | ||
|  |         if( ret == MBEDTLS_ERR_MPI_NOT_ACCEPTABLE ) | ||
|  |             return( MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED ); | ||
|  |         if( ret != 0 ) | ||
|  |             return( ret ); | ||
|  |     } | ||
|  | 
 | ||
|  |     /*
 | ||
|  |      * Calculate GX = G^X mod P | ||
|  |      */ | ||
|  |     MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->GX, &ctx->G, &ctx->X, | ||
|  |                           &ctx->P , &ctx->RP ) ); | ||
|  | 
 | ||
|  |     if( ( ret = dhm_check_range( &ctx->GX, &ctx->P ) ) != 0 ) | ||
|  |         return( ret ); | ||
|  | 
 | ||
|  | cleanup: | ||
|  |     return( ret ); | ||
|  | } | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Setup and write the ServerKeyExchange parameters | ||
|  |  */ | ||
|  | int mbedtls_dhm_make_params( mbedtls_dhm_context *ctx, int x_size, | ||
|  |                      unsigned char *output, size_t *olen, | ||
|  |                      int (*f_rng)(void *, unsigned char *, size_t), | ||
|  |                      void *p_rng ) | ||
|  | { | ||
|  |     int ret; | ||
|  |     size_t n1, n2, n3; | ||
|  |     unsigned char *p; | ||
|  |     DHM_VALIDATE_RET( ctx != NULL ); | ||
|  |     DHM_VALIDATE_RET( output != NULL ); | ||
|  |     DHM_VALIDATE_RET( olen != NULL ); | ||
|  |     DHM_VALIDATE_RET( f_rng != NULL ); | ||
|  | 
 | ||
|  |     ret = dhm_make_common( ctx, x_size, f_rng, p_rng ); | ||
|  |     if( ret != 0 ) | ||
|  |         goto cleanup; | ||
|  | 
 | ||
|  |     /*
 | ||
|  |      * Export P, G, GX. RFC 5246 §4.4 states that "leading zero octets are | ||
|  |      * not required". We omit leading zeros for compactness. | ||
|  |      */ | ||
|  | #define DHM_MPI_EXPORT( X, n )                                          \
 | ||
|  |     do {                                                                \ | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( ( X ),               \ | ||
|  |                                                    p + 2,               \ | ||
|  |                                                    ( n ) ) );           \ | ||
|  |         *p++ = MBEDTLS_BYTE_1( n );                                     \ | ||
|  |         *p++ = MBEDTLS_BYTE_0( n );                                     \ | ||
|  |         p += ( n );                                                     \ | ||
|  |     } while( 0 ) | ||
|  | 
 | ||
|  |     n1 = mbedtls_mpi_size( &ctx->P  ); | ||
|  |     n2 = mbedtls_mpi_size( &ctx->G  ); | ||
|  |     n3 = mbedtls_mpi_size( &ctx->GX ); | ||
|  | 
 | ||
|  |     p = output; | ||
|  |     DHM_MPI_EXPORT( &ctx->P , n1 ); | ||
|  |     DHM_MPI_EXPORT( &ctx->G , n2 ); | ||
|  |     DHM_MPI_EXPORT( &ctx->GX, n3 ); | ||
|  | 
 | ||
|  |     *olen = p - output; | ||
|  | 
 | ||
|  |     ctx->len = n1; | ||
|  | 
 | ||
|  | cleanup: | ||
|  |     if( ret != 0 && ret > -128 ) | ||
|  |         ret = MBEDTLS_ERROR_ADD( MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED, ret ); | ||
|  |     return( ret ); | ||
|  | } | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Set prime modulus and generator | ||
|  |  */ | ||
|  | int mbedtls_dhm_set_group( mbedtls_dhm_context *ctx, | ||
|  |                            const mbedtls_mpi *P, | ||
|  |                            const mbedtls_mpi *G ) | ||
|  | { | ||
|  |     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | ||
|  |     DHM_VALIDATE_RET( ctx != NULL ); | ||
|  |     DHM_VALIDATE_RET( P != NULL ); | ||
|  |     DHM_VALIDATE_RET( G != NULL ); | ||
|  | 
 | ||
|  |     if( ( ret = mbedtls_mpi_copy( &ctx->P, P ) ) != 0 || | ||
|  |         ( ret = mbedtls_mpi_copy( &ctx->G, G ) ) != 0 ) | ||
|  |     { | ||
|  |         return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_DHM_SET_GROUP_FAILED, ret ) ); | ||
|  |     } | ||
|  | 
 | ||
|  |     ctx->len = mbedtls_mpi_size( &ctx->P ); | ||
|  |     return( 0 ); | ||
|  | } | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Import the peer's public value G^Y | ||
|  |  */ | ||
|  | int mbedtls_dhm_read_public( mbedtls_dhm_context *ctx, | ||
|  |                      const unsigned char *input, size_t ilen ) | ||
|  | { | ||
|  |     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | ||
|  |     DHM_VALIDATE_RET( ctx != NULL ); | ||
|  |     DHM_VALIDATE_RET( input != NULL ); | ||
|  | 
 | ||
|  |     if( ilen < 1 || ilen > ctx->len ) | ||
|  |         return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); | ||
|  | 
 | ||
|  |     if( ( ret = mbedtls_mpi_read_binary( &ctx->GY, input, ilen ) ) != 0 ) | ||
|  |         return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_DHM_READ_PUBLIC_FAILED, ret ) ); | ||
|  | 
 | ||
|  |     return( 0 ); | ||
|  | } | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Create own private value X and export G^X | ||
|  |  */ | ||
|  | int mbedtls_dhm_make_public( mbedtls_dhm_context *ctx, int x_size, | ||
|  |                      unsigned char *output, size_t olen, | ||
|  |                      int (*f_rng)(void *, unsigned char *, size_t), | ||
|  |                      void *p_rng ) | ||
|  | { | ||
|  |     int ret; | ||
|  |     DHM_VALIDATE_RET( ctx != NULL ); | ||
|  |     DHM_VALIDATE_RET( output != NULL ); | ||
|  |     DHM_VALIDATE_RET( f_rng != NULL ); | ||
|  | 
 | ||
|  |     if( olen < 1 || olen > ctx->len ) | ||
|  |         return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); | ||
|  | 
 | ||
|  |     ret = dhm_make_common( ctx, x_size, f_rng, p_rng ); | ||
|  |     if( ret == MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED ) | ||
|  |         return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED ); | ||
|  |     if( ret != 0 ) | ||
|  |         goto cleanup; | ||
|  | 
 | ||
|  |     MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->GX, output, olen ) ); | ||
|  | 
 | ||
|  | cleanup: | ||
|  |     if( ret != 0 && ret > -128 ) | ||
|  |         ret = MBEDTLS_ERROR_ADD( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED, ret ); | ||
|  |     return( ret ); | ||
|  | } | ||
|  | 
 | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Use the blinding method and optimisation suggested in section 10 of: | ||
|  |  *  KOCHER, Paul C. Timing attacks on implementations of Diffie-Hellman, RSA, | ||
|  |  *  DSS, and other systems. In : Advances in Cryptology-CRYPTO'96. Springer | ||
|  |  *  Berlin Heidelberg, 1996. p. 104-113. | ||
|  |  */ | ||
|  | static int dhm_update_blinding( mbedtls_dhm_context *ctx, | ||
|  |                     int (*f_rng)(void *, unsigned char *, size_t), void *p_rng ) | ||
|  | { | ||
|  |     int ret; | ||
|  |     mbedtls_mpi R; | ||
|  | 
 | ||
|  |     mbedtls_mpi_init( &R ); | ||
|  | 
 | ||
|  |     /*
 | ||
|  |      * Don't use any blinding the first time a particular X is used, | ||
|  |      * but remember it to use blinding next time. | ||
|  |      */ | ||
|  |     if( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->pX ) != 0 ) | ||
|  |     { | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &ctx->pX, &ctx->X ) ); | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->Vi, 1 ) ); | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &ctx->Vf, 1 ) ); | ||
|  | 
 | ||
|  |         return( 0 ); | ||
|  |     } | ||
|  | 
 | ||
|  |     /*
 | ||
|  |      * Ok, we need blinding. Can we re-use existing values? | ||
|  |      * If yes, just update them by squaring them. | ||
|  |      */ | ||
|  |     if( mbedtls_mpi_cmp_int( &ctx->Vi, 1 ) != 0 ) | ||
|  |     { | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vi, &ctx->Vi, &ctx->Vi ) ); | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vi, &ctx->Vi, &ctx->P ) ); | ||
|  | 
 | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vf, &ctx->Vf, &ctx->Vf ) ); | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vf, &ctx->Vf, &ctx->P ) ); | ||
|  | 
 | ||
|  |         return( 0 ); | ||
|  |     } | ||
|  | 
 | ||
|  |     /*
 | ||
|  |      * We need to generate blinding values from scratch | ||
|  |      */ | ||
|  | 
 | ||
|  |     /* Vi = random( 2, P-2 ) */ | ||
|  |     MBEDTLS_MPI_CHK( dhm_random_below( &ctx->Vi, &ctx->P, f_rng, p_rng ) ); | ||
|  | 
 | ||
|  |     /* Vf = Vi^-X mod P
 | ||
|  |      * First compute Vi^-1 = R * (R Vi)^-1, (avoiding leaks from inv_mod), | ||
|  |      * then elevate to the Xth power. */ | ||
|  |     MBEDTLS_MPI_CHK( dhm_random_below( &R, &ctx->P, f_rng, p_rng ) ); | ||
|  |     MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vf, &ctx->Vi, &R ) ); | ||
|  |     MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vf, &ctx->Vf, &ctx->P ) ); | ||
|  |     MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->Vf, &ctx->Vf, &ctx->P ) ); | ||
|  |     MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->Vf, &ctx->Vf, &R ) ); | ||
|  |     MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->Vf, &ctx->Vf, &ctx->P ) ); | ||
|  | 
 | ||
|  |     MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->Vf, &ctx->Vf, &ctx->X, &ctx->P, &ctx->RP ) ); | ||
|  | 
 | ||
|  | cleanup: | ||
|  |     mbedtls_mpi_free( &R ); | ||
|  | 
 | ||
|  |     return( ret ); | ||
|  | } | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Derive and export the shared secret (G^Y)^X mod P | ||
|  |  */ | ||
|  | int mbedtls_dhm_calc_secret( mbedtls_dhm_context *ctx, | ||
|  |                      unsigned char *output, size_t output_size, size_t *olen, | ||
|  |                      int (*f_rng)(void *, unsigned char *, size_t), | ||
|  |                      void *p_rng ) | ||
|  | { | ||
|  |     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | ||
|  |     mbedtls_mpi GYb; | ||
|  |     DHM_VALIDATE_RET( ctx != NULL ); | ||
|  |     DHM_VALIDATE_RET( output != NULL ); | ||
|  |     DHM_VALIDATE_RET( olen != NULL ); | ||
|  | 
 | ||
|  |     if( output_size < ctx->len ) | ||
|  |         return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); | ||
|  | 
 | ||
|  |     if( ( ret = dhm_check_range( &ctx->GY, &ctx->P ) ) != 0 ) | ||
|  |         return( ret ); | ||
|  | 
 | ||
|  |     mbedtls_mpi_init( &GYb ); | ||
|  | 
 | ||
|  |     /* Blind peer's value */ | ||
|  |     if( f_rng != NULL ) | ||
|  |     { | ||
|  |         MBEDTLS_MPI_CHK( dhm_update_blinding( ctx, f_rng, p_rng ) ); | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &GYb, &ctx->GY, &ctx->Vi ) ); | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &GYb, &GYb, &ctx->P ) ); | ||
|  |     } | ||
|  |     else | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_copy( &GYb, &ctx->GY ) ); | ||
|  | 
 | ||
|  |     /* Do modular exponentiation */ | ||
|  |     MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->K, &GYb, &ctx->X, | ||
|  |                           &ctx->P, &ctx->RP ) ); | ||
|  | 
 | ||
|  |     /* Unblind secret value */ | ||
|  |     if( f_rng != NULL ) | ||
|  |     { | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_mul_mpi( &ctx->K, &ctx->K, &ctx->Vf ) ); | ||
|  |         MBEDTLS_MPI_CHK( mbedtls_mpi_mod_mpi( &ctx->K, &ctx->K, &ctx->P ) ); | ||
|  |     } | ||
|  | 
 | ||
|  |     /* Output the secret without any leading zero byte. This is mandatory
 | ||
|  |      * for TLS per RFC 5246 §8.1.2. */ | ||
|  |     *olen = mbedtls_mpi_size( &ctx->K ); | ||
|  |     MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->K, output, *olen ) ); | ||
|  | 
 | ||
|  | cleanup: | ||
|  |     mbedtls_mpi_free( &GYb ); | ||
|  | 
 | ||
|  |     if( ret != 0 ) | ||
|  |         return( MBEDTLS_ERROR_ADD( MBEDTLS_ERR_DHM_CALC_SECRET_FAILED, ret ) ); | ||
|  | 
 | ||
|  |     return( 0 ); | ||
|  | } | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Free the components of a DHM key | ||
|  |  */ | ||
|  | void mbedtls_dhm_free( mbedtls_dhm_context *ctx ) | ||
|  | { | ||
|  |     if( ctx == NULL ) | ||
|  |         return; | ||
|  | 
 | ||
|  |     mbedtls_mpi_free( &ctx->pX ); | ||
|  |     mbedtls_mpi_free( &ctx->Vf ); | ||
|  |     mbedtls_mpi_free( &ctx->Vi ); | ||
|  |     mbedtls_mpi_free( &ctx->RP ); | ||
|  |     mbedtls_mpi_free( &ctx->K  ); | ||
|  |     mbedtls_mpi_free( &ctx->GY ); | ||
|  |     mbedtls_mpi_free( &ctx->GX ); | ||
|  |     mbedtls_mpi_free( &ctx->X  ); | ||
|  |     mbedtls_mpi_free( &ctx->G  ); | ||
|  |     mbedtls_mpi_free( &ctx->P  ); | ||
|  | 
 | ||
|  |     mbedtls_platform_zeroize( ctx, sizeof( mbedtls_dhm_context ) ); | ||
|  | } | ||
|  | 
 | ||
|  | #if defined(MBEDTLS_ASN1_PARSE_C)
 | ||
|  | /*
 | ||
|  |  * Parse DHM parameters | ||
|  |  */ | ||
|  | int mbedtls_dhm_parse_dhm( mbedtls_dhm_context *dhm, const unsigned char *dhmin, | ||
|  |                    size_t dhminlen ) | ||
|  | { | ||
|  |     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | ||
|  |     size_t len; | ||
|  |     unsigned char *p, *end; | ||
|  | #if defined(MBEDTLS_PEM_PARSE_C)
 | ||
|  |     mbedtls_pem_context pem; | ||
|  | #endif /* MBEDTLS_PEM_PARSE_C */
 | ||
|  | 
 | ||
|  |     DHM_VALIDATE_RET( dhm != NULL ); | ||
|  |     DHM_VALIDATE_RET( dhmin != NULL ); | ||
|  | 
 | ||
|  | #if defined(MBEDTLS_PEM_PARSE_C)
 | ||
|  |     mbedtls_pem_init( &pem ); | ||
|  | 
 | ||
|  |     /* Avoid calling mbedtls_pem_read_buffer() on non-null-terminated string */ | ||
|  |     if( dhminlen == 0 || dhmin[dhminlen - 1] != '\0' ) | ||
|  |         ret = MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT; | ||
|  |     else | ||
|  |         ret = mbedtls_pem_read_buffer( &pem, | ||
|  |                                "-----BEGIN DH PARAMETERS-----", | ||
|  |                                "-----END DH PARAMETERS-----", | ||
|  |                                dhmin, NULL, 0, &dhminlen ); | ||
|  | 
 | ||
|  |     if( ret == 0 ) | ||
|  |     { | ||
|  |         /*
 | ||
|  |          * Was PEM encoded | ||
|  |          */ | ||
|  |         dhminlen = pem.buflen; | ||
|  |     } | ||
|  |     else if( ret != MBEDTLS_ERR_PEM_NO_HEADER_FOOTER_PRESENT ) | ||
|  |         goto exit; | ||
|  | 
 | ||
|  |     p = ( ret == 0 ) ? pem.buf : (unsigned char *) dhmin; | ||
|  | #else
 | ||
|  |     p = (unsigned char *) dhmin; | ||
|  | #endif /* MBEDTLS_PEM_PARSE_C */
 | ||
|  |     end = p + dhminlen; | ||
|  | 
 | ||
|  |     /*
 | ||
|  |      *  DHParams ::= SEQUENCE { | ||
|  |      *      prime              INTEGER,  -- P | ||
|  |      *      generator          INTEGER,  -- g | ||
|  |      *      privateValueLength INTEGER OPTIONAL | ||
|  |      *  } | ||
|  |      */ | ||
|  |     if( ( ret = mbedtls_asn1_get_tag( &p, end, &len, | ||
|  |             MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) ) != 0 ) | ||
|  |     { | ||
|  |         ret = MBEDTLS_ERROR_ADD( MBEDTLS_ERR_DHM_INVALID_FORMAT, ret ); | ||
|  |         goto exit; | ||
|  |     } | ||
|  | 
 | ||
|  |     end = p + len; | ||
|  | 
 | ||
|  |     if( ( ret = mbedtls_asn1_get_mpi( &p, end, &dhm->P  ) ) != 0 || | ||
|  |         ( ret = mbedtls_asn1_get_mpi( &p, end, &dhm->G ) ) != 0 ) | ||
|  |     { | ||
|  |         ret = MBEDTLS_ERROR_ADD( MBEDTLS_ERR_DHM_INVALID_FORMAT, ret ); | ||
|  |         goto exit; | ||
|  |     } | ||
|  | 
 | ||
|  |     if( p != end ) | ||
|  |     { | ||
|  |         /* This might be the optional privateValueLength.
 | ||
|  |          * If so, we can cleanly discard it */ | ||
|  |         mbedtls_mpi rec; | ||
|  |         mbedtls_mpi_init( &rec ); | ||
|  |         ret = mbedtls_asn1_get_mpi( &p, end, &rec ); | ||
|  |         mbedtls_mpi_free( &rec ); | ||
|  |         if ( ret != 0 ) | ||
|  |         { | ||
|  |             ret = MBEDTLS_ERROR_ADD( MBEDTLS_ERR_DHM_INVALID_FORMAT, ret ); | ||
|  |             goto exit; | ||
|  |         } | ||
|  |         if ( p != end ) | ||
|  |         { | ||
|  |             ret = MBEDTLS_ERROR_ADD( MBEDTLS_ERR_DHM_INVALID_FORMAT, | ||
|  |                 MBEDTLS_ERR_ASN1_LENGTH_MISMATCH ); | ||
|  |             goto exit; | ||
|  |         } | ||
|  |     } | ||
|  | 
 | ||
|  |     ret = 0; | ||
|  | 
 | ||
|  |     dhm->len = mbedtls_mpi_size( &dhm->P ); | ||
|  | 
 | ||
|  | exit: | ||
|  | #if defined(MBEDTLS_PEM_PARSE_C)
 | ||
|  |     mbedtls_pem_free( &pem ); | ||
|  | #endif
 | ||
|  |     if( ret != 0 ) | ||
|  |         mbedtls_dhm_free( dhm ); | ||
|  | 
 | ||
|  |     return( ret ); | ||
|  | } | ||
|  | 
 | ||
|  | #if defined(MBEDTLS_FS_IO)
 | ||
|  | /*
 | ||
|  |  * Load all data from a file into a given buffer. | ||
|  |  * | ||
|  |  * The file is expected to contain either PEM or DER encoded data. | ||
|  |  * A terminating null byte is always appended. It is included in the announced | ||
|  |  * length only if the data looks like it is PEM encoded. | ||
|  |  */ | ||
|  | static int load_file( const char *path, unsigned char **buf, size_t *n ) | ||
|  | { | ||
|  |     FILE *f; | ||
|  |     long size; | ||
|  | 
 | ||
|  |     if( ( f = fopen( path, "rb" ) ) == NULL ) | ||
|  |         return( MBEDTLS_ERR_DHM_FILE_IO_ERROR ); | ||
|  | 
 | ||
|  |     fseek( f, 0, SEEK_END ); | ||
|  |     if( ( size = ftell( f ) ) == -1 ) | ||
|  |     { | ||
|  |         fclose( f ); | ||
|  |         return( MBEDTLS_ERR_DHM_FILE_IO_ERROR ); | ||
|  |     } | ||
|  |     fseek( f, 0, SEEK_SET ); | ||
|  | 
 | ||
|  |     *n = (size_t) size; | ||
|  | 
 | ||
|  |     if( *n + 1 == 0 || | ||
|  |         ( *buf = mbedtls_calloc( 1, *n + 1 ) ) == NULL ) | ||
|  |     { | ||
|  |         fclose( f ); | ||
|  |         return( MBEDTLS_ERR_DHM_ALLOC_FAILED ); | ||
|  |     } | ||
|  | 
 | ||
|  |     if( fread( *buf, 1, *n, f ) != *n ) | ||
|  |     { | ||
|  |         fclose( f ); | ||
|  | 
 | ||
|  |         mbedtls_platform_zeroize( *buf, *n + 1 ); | ||
|  |         mbedtls_free( *buf ); | ||
|  | 
 | ||
|  |         return( MBEDTLS_ERR_DHM_FILE_IO_ERROR ); | ||
|  |     } | ||
|  | 
 | ||
|  |     fclose( f ); | ||
|  | 
 | ||
|  |     (*buf)[*n] = '\0'; | ||
|  | 
 | ||
|  |     if( strstr( (const char *) *buf, "-----BEGIN " ) != NULL ) | ||
|  |         ++*n; | ||
|  | 
 | ||
|  |     return( 0 ); | ||
|  | } | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Load and parse DHM parameters | ||
|  |  */ | ||
|  | int mbedtls_dhm_parse_dhmfile( mbedtls_dhm_context *dhm, const char *path ) | ||
|  | { | ||
|  |     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | ||
|  |     size_t n; | ||
|  |     unsigned char *buf; | ||
|  |     DHM_VALIDATE_RET( dhm != NULL ); | ||
|  |     DHM_VALIDATE_RET( path != NULL ); | ||
|  | 
 | ||
|  |     if( ( ret = load_file( path, &buf, &n ) ) != 0 ) | ||
|  |         return( ret ); | ||
|  | 
 | ||
|  |     ret = mbedtls_dhm_parse_dhm( dhm, buf, n ); | ||
|  | 
 | ||
|  |     mbedtls_platform_zeroize( buf, n ); | ||
|  |     mbedtls_free( buf ); | ||
|  | 
 | ||
|  |     return( ret ); | ||
|  | } | ||
|  | #endif /* MBEDTLS_FS_IO */
 | ||
|  | #endif /* MBEDTLS_ASN1_PARSE_C */
 | ||
|  | #endif /* MBEDTLS_DHM_ALT */
 | ||
|  | 
 | ||
|  | #if defined(MBEDTLS_SELF_TEST)
 | ||
|  | 
 | ||
|  | #if defined(MBEDTLS_PEM_PARSE_C)
 | ||
|  | static const char mbedtls_test_dhm_params[] = | ||
|  | "-----BEGIN DH PARAMETERS-----\r\n" | ||
|  | "MIGHAoGBAJ419DBEOgmQTzo5qXl5fQcN9TN455wkOL7052HzxxRVMyhYmwQcgJvh\r\n" | ||
|  | "1sa18fyfR9OiVEMYglOpkqVoGLN7qd5aQNNi5W7/C+VBdHTBJcGZJyyP5B3qcz32\r\n" | ||
|  | "9mLJKudlVudV0Qxk5qUJaPZ/xupz0NyoVpviuiBOI1gNi8ovSXWzAgEC\r\n" | ||
|  | "-----END DH PARAMETERS-----\r\n"; | ||
|  | #else /* MBEDTLS_PEM_PARSE_C */
 | ||
|  | static const char mbedtls_test_dhm_params[] = { | ||
|  |   0x30, 0x81, 0x87, 0x02, 0x81, 0x81, 0x00, 0x9e, 0x35, 0xf4, 0x30, 0x44, | ||
|  |   0x3a, 0x09, 0x90, 0x4f, 0x3a, 0x39, 0xa9, 0x79, 0x79, 0x7d, 0x07, 0x0d, | ||
|  |   0xf5, 0x33, 0x78, 0xe7, 0x9c, 0x24, 0x38, 0xbe, 0xf4, 0xe7, 0x61, 0xf3, | ||
|  |   0xc7, 0x14, 0x55, 0x33, 0x28, 0x58, 0x9b, 0x04, 0x1c, 0x80, 0x9b, 0xe1, | ||
|  |   0xd6, 0xc6, 0xb5, 0xf1, 0xfc, 0x9f, 0x47, 0xd3, 0xa2, 0x54, 0x43, 0x18, | ||
|  |   0x82, 0x53, 0xa9, 0x92, 0xa5, 0x68, 0x18, 0xb3, 0x7b, 0xa9, 0xde, 0x5a, | ||
|  |   0x40, 0xd3, 0x62, 0xe5, 0x6e, 0xff, 0x0b, 0xe5, 0x41, 0x74, 0x74, 0xc1, | ||
|  |   0x25, 0xc1, 0x99, 0x27, 0x2c, 0x8f, 0xe4, 0x1d, 0xea, 0x73, 0x3d, 0xf6, | ||
|  |   0xf6, 0x62, 0xc9, 0x2a, 0xe7, 0x65, 0x56, 0xe7, 0x55, 0xd1, 0x0c, 0x64, | ||
|  |   0xe6, 0xa5, 0x09, 0x68, 0xf6, 0x7f, 0xc6, 0xea, 0x73, 0xd0, 0xdc, 0xa8, | ||
|  |   0x56, 0x9b, 0xe2, 0xba, 0x20, 0x4e, 0x23, 0x58, 0x0d, 0x8b, 0xca, 0x2f, | ||
|  |   0x49, 0x75, 0xb3, 0x02, 0x01, 0x02 }; | ||
|  | #endif /* MBEDTLS_PEM_PARSE_C */
 | ||
|  | 
 | ||
|  | static const size_t mbedtls_test_dhm_params_len = sizeof( mbedtls_test_dhm_params ); | ||
|  | 
 | ||
|  | /*
 | ||
|  |  * Checkup routine | ||
|  |  */ | ||
|  | int mbedtls_dhm_self_test( int verbose ) | ||
|  | { | ||
|  |     int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED; | ||
|  |     mbedtls_dhm_context dhm; | ||
|  | 
 | ||
|  |     mbedtls_dhm_init( &dhm ); | ||
|  | 
 | ||
|  |     if( verbose != 0 ) | ||
|  |         mbedtls_printf( "  DHM parameter load: " ); | ||
|  | 
 | ||
|  |     if( ( ret = mbedtls_dhm_parse_dhm( &dhm, | ||
|  |                     (const unsigned char *) mbedtls_test_dhm_params, | ||
|  |                     mbedtls_test_dhm_params_len ) ) != 0 ) | ||
|  |     { | ||
|  |         if( verbose != 0 ) | ||
|  |             mbedtls_printf( "failed\n" ); | ||
|  | 
 | ||
|  |         ret = 1; | ||
|  |         goto exit; | ||
|  |     } | ||
|  | 
 | ||
|  |     if( verbose != 0 ) | ||
|  |         mbedtls_printf( "passed\n\n" ); | ||
|  | 
 | ||
|  | exit: | ||
|  |     mbedtls_dhm_free( &dhm ); | ||
|  | 
 | ||
|  |     return( ret ); | ||
|  | } | ||
|  | 
 | ||
|  | #endif /* MBEDTLS_SELF_TEST */
 | ||
|  | 
 | ||
|  | #endif /* MBEDTLS_DHM_C */
 |