/* BEGIN_HEADER */
#include "mbedtls/dhm.h"

/* Sanity checks on a Diffie-Hellman parameter: check the length-value
 * syntax and check that the value is the expected one (taken from the
 * DHM context by the caller). */
static int check_dhm_param_output( const mbedtls_mpi *expected,
                                   const unsigned char *buffer,
                                   size_t size,
                                   size_t *offset )
{
    size_t n;
    mbedtls_mpi actual;
    int ok = 0;
    mbedtls_mpi_init( &actual );

    ++mbedtls_test_info.step;

    TEST_ASSERT( size >= *offset + 2 );
    n = ( buffer[*offset] << 8 ) | buffer[*offset + 1];
    *offset += 2;
    /* The DHM param output from Mbed TLS has leading zeros stripped, as
     * permitted but not required by RFC 5246 \S4.4. */
    TEST_EQUAL( n, mbedtls_mpi_size( expected ) );
    TEST_ASSERT( size >= *offset + n );
    TEST_EQUAL( 0, mbedtls_mpi_read_binary( &actual, buffer + *offset, n ) );
    TEST_EQUAL( 0, mbedtls_mpi_cmp_mpi( expected, &actual ) );
    *offset += n;

    ok = 1;
exit:
    mbedtls_mpi_free( &actual );
    return( ok );
}

/* Sanity checks on Diffie-Hellman parameters: syntax, range, and comparison
 * against the context. */
static int check_dhm_params( const mbedtls_dhm_context *ctx,
                             size_t x_size,
                             const unsigned char *ske, size_t ske_len )
{
    size_t offset = 0;

    /* Check that ctx->X and ctx->GX are within range. */
    TEST_ASSERT( mbedtls_mpi_cmp_int( &ctx->X, 1 ) > 0 );
    TEST_ASSERT( mbedtls_mpi_cmp_mpi( &ctx->X, &ctx->P ) < 0 );
    TEST_ASSERT( mbedtls_mpi_size( &ctx->X ) <= x_size );
    TEST_ASSERT( mbedtls_mpi_cmp_int( &ctx->GX, 1 ) > 0 );
    TEST_ASSERT( mbedtls_mpi_cmp_mpi( &ctx->GX, &ctx->P ) < 0 );

    /* Check ske: it must contain P, G and G^X, each prefixed with a
     * 2-byte size. */
    if( !check_dhm_param_output( &ctx->P, ske, ske_len, &offset ) )
        goto exit;
    if( !check_dhm_param_output( &ctx->G, ske, ske_len, &offset ) )
        goto exit;
    if( !check_dhm_param_output( &ctx->GX, ske, ske_len, &offset ) )
        goto exit;
    TEST_EQUAL( offset, ske_len );

    return( 1 );
exit:
    return( 0 );
}

/* END_HEADER */

/* BEGIN_DEPENDENCIES
 * depends_on:MBEDTLS_DHM_C:MBEDTLS_BIGNUM_C
 * END_DEPENDENCIES
 */

/* BEGIN_CASE */
void dhm_do_dhm( int radix_P, char *input_P, int x_size,
                 int radix_G, char *input_G, int result )
{
    mbedtls_dhm_context ctx_srv;
    mbedtls_dhm_context ctx_cli;
    unsigned char ske[1000];
    unsigned char *p = ske;
    unsigned char pub_cli[1000];
    unsigned char sec_srv[1000];
    unsigned char sec_cli[1000];
    size_t ske_len = 0;
    size_t pub_cli_len = 0;
    size_t sec_srv_len;
    size_t sec_cli_len;
    int i;
    mbedtls_test_rnd_pseudo_info rnd_info;

    mbedtls_dhm_init( &ctx_srv );
    mbedtls_dhm_init( &ctx_cli );
    memset( ske, 0x00, 1000 );
    memset( pub_cli, 0x00, 1000 );
    memset( sec_srv, 0x00, 1000 );
    memset( sec_cli, 0x00, 1000 );
    memset( &rnd_info, 0x00, sizeof( mbedtls_test_rnd_pseudo_info ) );

    /*
     * Set params
     */
    TEST_ASSERT( mbedtls_mpi_read_string( &ctx_srv.P, radix_P, input_P ) == 0 );
    TEST_ASSERT( mbedtls_mpi_read_string( &ctx_srv.G, radix_G, input_G ) == 0 );
    pub_cli_len = mbedtls_mpi_size( &ctx_srv.P );

    /*
     * First key exchange
     */
    mbedtls_test_set_step( 10 );
    TEST_ASSERT( mbedtls_dhm_make_params( &ctx_srv, x_size, ske, &ske_len,
                                          &mbedtls_test_rnd_pseudo_rand,
                                          &rnd_info ) == result );
    if ( result != 0 )
        goto exit;
    if( !check_dhm_params( &ctx_srv, x_size, ske, ske_len ) )
        goto exit;

    ske[ske_len++] = 0;
    ske[ske_len++] = 0;
    TEST_ASSERT( mbedtls_dhm_read_params( &ctx_cli, &p, ske + ske_len ) == 0 );

    TEST_ASSERT( mbedtls_dhm_make_public( &ctx_cli, x_size, pub_cli, pub_cli_len,
                                          &mbedtls_test_rnd_pseudo_rand,
                                          &rnd_info ) == 0 );
    TEST_ASSERT( mbedtls_dhm_read_public( &ctx_srv, pub_cli, pub_cli_len ) == 0 );

    TEST_ASSERT( mbedtls_dhm_calc_secret( &ctx_srv, sec_srv, sizeof( sec_srv ),
                                          &sec_srv_len,
                                          &mbedtls_test_rnd_pseudo_rand,
                                          &rnd_info ) == 0 );
    TEST_ASSERT( mbedtls_dhm_calc_secret( &ctx_cli, sec_cli, sizeof( sec_cli ), &sec_cli_len, NULL, NULL ) == 0 );

    TEST_ASSERT( sec_srv_len == sec_cli_len );
    TEST_ASSERT( sec_srv_len != 0 );
    TEST_ASSERT( memcmp( sec_srv, sec_cli, sec_srv_len ) == 0 );

    /* Re-do calc_secret on server a few times to test update of blinding values */
    for( i = 0; i < 3; i++ )
    {
        mbedtls_test_set_step( 20 + i );
        sec_srv_len = 1000;
        TEST_ASSERT( mbedtls_dhm_calc_secret( &ctx_srv, sec_srv,
                                              sizeof( sec_srv ), &sec_srv_len,
                                              &mbedtls_test_rnd_pseudo_rand,
                                              &rnd_info ) == 0 );

        TEST_ASSERT( sec_srv_len == sec_cli_len );
        TEST_ASSERT( sec_srv_len != 0 );
        TEST_ASSERT( memcmp( sec_srv, sec_cli, sec_srv_len ) == 0 );
    }

    /*
     * Second key exchange to test change of blinding values on server
     */
    p = ske;

    mbedtls_test_set_step( 30 );
    TEST_ASSERT( mbedtls_dhm_make_params( &ctx_srv, x_size, ske, &ske_len,
                                          &mbedtls_test_rnd_pseudo_rand,
                                          &rnd_info ) == 0 );
    if( !check_dhm_params( &ctx_srv, x_size, ske, ske_len ) )
        goto exit;
    ske[ske_len++] = 0;
    ske[ske_len++] = 0;
    TEST_ASSERT( mbedtls_dhm_read_params( &ctx_cli, &p, ske + ske_len ) == 0 );

    TEST_ASSERT( mbedtls_dhm_make_public( &ctx_cli, x_size, pub_cli, pub_cli_len,
                                          &mbedtls_test_rnd_pseudo_rand,
                                          &rnd_info ) == 0 );
    TEST_ASSERT( mbedtls_dhm_read_public( &ctx_srv, pub_cli, pub_cli_len ) == 0 );

    TEST_ASSERT( mbedtls_dhm_calc_secret( &ctx_srv, sec_srv, sizeof( sec_srv ),
                                          &sec_srv_len,
                                          &mbedtls_test_rnd_pseudo_rand,
                                          &rnd_info ) == 0 );
    TEST_ASSERT( mbedtls_dhm_calc_secret( &ctx_cli, sec_cli, sizeof( sec_cli ), &sec_cli_len, NULL, NULL ) == 0 );

    TEST_ASSERT( sec_srv_len == sec_cli_len );
    TEST_ASSERT( sec_srv_len != 0 );
    TEST_ASSERT( memcmp( sec_srv, sec_cli, sec_srv_len ) == 0 );

exit:
    mbedtls_dhm_free( &ctx_srv );
    mbedtls_dhm_free( &ctx_cli );
}
/* END_CASE */

/* BEGIN_CASE */
void dhm_make_public( int P_bytes, int radix_G, char *input_G, int result )
{
    mbedtls_mpi P, G;
    mbedtls_dhm_context ctx;
    unsigned char output[MBEDTLS_MPI_MAX_SIZE];

    mbedtls_mpi_init( &P );
    mbedtls_mpi_init( &G );
    mbedtls_dhm_init( &ctx );

    TEST_ASSERT( mbedtls_mpi_lset( &P, 1 ) == 0 );
    TEST_ASSERT( mbedtls_mpi_shift_l( &P, ( P_bytes * 8 ) - 1 ) == 0 );
    TEST_ASSERT( mbedtls_mpi_set_bit( &P, 0, 1 ) == 0 );

    TEST_ASSERT( mbedtls_mpi_read_string( &G, radix_G, input_G ) == 0 );

    TEST_ASSERT( mbedtls_dhm_set_group( &ctx, &P, &G ) == 0 );
    TEST_ASSERT( mbedtls_dhm_make_public( &ctx, (int) mbedtls_mpi_size( &P ),
                                          output, sizeof(output),
                                          &mbedtls_test_rnd_pseudo_rand,
                                          NULL ) == result );

exit:
    mbedtls_mpi_free( &P );
    mbedtls_mpi_free( &G );
    mbedtls_dhm_free( &ctx );
}
/* END_CASE */

/* BEGIN_CASE depends_on:MBEDTLS_FS_IO */
void dhm_file( char * filename, char * p, char * g, int len )
{
    mbedtls_dhm_context ctx;
    mbedtls_mpi P, G;

    mbedtls_dhm_init( &ctx );
    mbedtls_mpi_init( &P ); mbedtls_mpi_init( &G );

    TEST_ASSERT( mbedtls_mpi_read_string( &P, 16, p ) == 0 );
    TEST_ASSERT( mbedtls_mpi_read_string( &G, 16, g ) == 0 );

    TEST_ASSERT( mbedtls_dhm_parse_dhmfile( &ctx, filename ) == 0 );

    TEST_ASSERT( ctx.len == (size_t) len );
    TEST_ASSERT( mbedtls_mpi_cmp_mpi( &ctx.P, &P ) == 0 );
    TEST_ASSERT( mbedtls_mpi_cmp_mpi( &ctx.G, &G ) == 0 );

exit:
    mbedtls_mpi_free( &P ); mbedtls_mpi_free( &G );
    mbedtls_dhm_free( &ctx );
}
/* END_CASE */

/* BEGIN_CASE depends_on:MBEDTLS_SELF_TEST */
void dhm_selftest(  )
{
    TEST_ASSERT( mbedtls_dhm_self_test( 1 ) == 0 );
}
/* END_CASE */