diff options
Diffstat (limited to 'thirdparty/mbedtls/library/dhm.c')
| -rw-r--r-- | thirdparty/mbedtls/library/dhm.c | 663 |
1 files changed, 663 insertions, 0 deletions
diff --git a/thirdparty/mbedtls/library/dhm.c b/thirdparty/mbedtls/library/dhm.c new file mode 100644 index 0000000000..28ac31003c --- /dev/null +++ b/thirdparty/mbedtls/library/dhm.c @@ -0,0 +1,663 @@ +/* + * Diffie-Hellman-Merkle key exchange + * + * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved + * 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. + * + * This file is part of mbed TLS (https://tls.mbed.org) + */ +/* + * 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 + * + */ + +#if !defined(MBEDTLS_CONFIG_FILE) +#include "mbedtls/config.h" +#else +#include MBEDTLS_CONFIG_FILE +#endif + +#if defined(MBEDTLS_DHM_C) + +#include "mbedtls/dhm.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 + +#if defined(MBEDTLS_PLATFORM_C) +#include "mbedtls/platform.h" +#else +#include <stdlib.h> +#include <stdio.h> +#define mbedtls_printf printf +#define mbedtls_calloc calloc +#define mbedtls_free free +#endif + +#if !defined(MBEDTLS_DHM_ALT) +/* Implementation that should never be optimized out by the compiler */ +static void mbedtls_zeroize( void *v, size_t n ) { + volatile unsigned char *p = v; while( n-- ) *p++ = 0; +} + +/* + * 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_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 L, U; + int ret = 0; + + mbedtls_mpi_init( &L ); mbedtls_mpi_init( &U ); + + MBEDTLS_MPI_CHK( mbedtls_mpi_lset( &L, 2 ) ); + MBEDTLS_MPI_CHK( mbedtls_mpi_sub_int( &U, P, 2 ) ); + + if( mbedtls_mpi_cmp_mpi( param, &L ) < 0 || + mbedtls_mpi_cmp_mpi( param, &U ) > 0 ) + { + ret = MBEDTLS_ERR_DHM_BAD_INPUT_DATA; + } + +cleanup: + mbedtls_mpi_free( &L ); mbedtls_mpi_free( &U ); + return( ret ); +} + +void mbedtls_dhm_init( mbedtls_dhm_context *ctx ) +{ + 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; + + 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 ); +} + +/* + * 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, count = 0; + size_t n1, n2, n3; + unsigned char *p; + + if( mbedtls_mpi_cmp_int( &ctx->P, 0 ) == 0 ) + return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); + + /* + * Generate X as large as possible ( < P ) + */ + do + { + MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng ) ); + + while( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 ) + MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->X, 1 ) ); + + if( count++ > 10 ) + return( MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED ); + } + while( dhm_check_range( &ctx->X, &ctx->P ) != 0 ); + + /* + * 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 ); + + /* + * export P, G, GX + */ +#define DHM_MPI_EXPORT( X, n ) \ + do { \ + MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( ( X ), \ + p + 2, \ + ( n ) ) ); \ + *p++ = (unsigned char)( ( n ) >> 8 ); \ + *p++ = (unsigned char)( ( 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 ) + return( MBEDTLS_ERR_DHM_MAKE_PARAMS_FAILED + ret ); + + return( 0 ); +} + +/* + * Set prime modulus and generator + */ +int mbedtls_dhm_set_group( mbedtls_dhm_context *ctx, + const mbedtls_mpi *P, + const mbedtls_mpi *G ) +{ + int ret; + + if( ctx == NULL || P == NULL || G == NULL ) + return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); + + if( ( ret = mbedtls_mpi_copy( &ctx->P, P ) ) != 0 || + ( ret = mbedtls_mpi_copy( &ctx->G, G ) ) != 0 ) + { + return( 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; + + if( ctx == NULL || 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_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, count = 0; + + if( ctx == NULL || olen < 1 || olen > ctx->len ) + return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); + + if( mbedtls_mpi_cmp_int( &ctx->P, 0 ) == 0 ) + return( MBEDTLS_ERR_DHM_BAD_INPUT_DATA ); + + /* + * generate X and calculate GX = G^X mod P + */ + do + { + MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->X, x_size, f_rng, p_rng ) ); + + while( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) >= 0 ) + MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->X, 1 ) ); + + if( count++ > 10 ) + return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED ); + } + while( dhm_check_range( &ctx->X, &ctx->P ) != 0 ); + + 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 ); + + MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( &ctx->GX, output, olen ) ); + +cleanup: + + if( ret != 0 ) + return( MBEDTLS_ERR_DHM_MAKE_PUBLIC_FAILED + ret ); + + return( 0 ); +} + +/* + * 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, count; + + /* + * 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-1 ) */ + count = 0; + do + { + MBEDTLS_MPI_CHK( mbedtls_mpi_fill_random( &ctx->Vi, mbedtls_mpi_size( &ctx->P ), f_rng, p_rng ) ); + + while( mbedtls_mpi_cmp_mpi( &ctx->Vi, &ctx->P ) >= 0 ) + MBEDTLS_MPI_CHK( mbedtls_mpi_shift_r( &ctx->Vi, 1 ) ); + + if( count++ > 10 ) + return( MBEDTLS_ERR_MPI_NOT_ACCEPTABLE ); + } + while( mbedtls_mpi_cmp_int( &ctx->Vi, 1 ) <= 0 ); + + /* Vf = Vi^-X mod P */ + MBEDTLS_MPI_CHK( mbedtls_mpi_inv_mod( &ctx->Vf, &ctx->Vi, &ctx->P ) ); + MBEDTLS_MPI_CHK( mbedtls_mpi_exp_mod( &ctx->Vf, &ctx->Vf, &ctx->X, &ctx->P, &ctx->RP ) ); + +cleanup: + 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_mpi GYb; + + if( ctx == NULL || 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 ) ); + } + + *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_ERR_DHM_CALC_SECRET_FAILED + ret ); + + return( 0 ); +} + +/* + * Free the components of a DHM key + */ +void mbedtls_dhm_free( mbedtls_dhm_context *ctx ) +{ + 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_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; + size_t len; + unsigned char *p, *end; +#if defined(MBEDTLS_PEM_PARSE_C) + mbedtls_pem_context pem; + + 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_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_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_ERR_DHM_INVALID_FORMAT + ret; + goto exit; + } + if ( p != end ) + { + ret = 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_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; + size_t n; + unsigned char *buf; + + if( ( ret = load_file( path, &buf, &n ) ) != 0 ) + return( ret ); + + ret = mbedtls_dhm_parse_dhm( dhm, buf, n ); + + mbedtls_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) + +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"; + +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_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 */ |