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

typedef struct
{
    unsigned char *p;
    size_t len;
} entropy_ctx;

int mbedtls_entropy_func( void *data, unsigned char *buf, size_t len )
{
    entropy_ctx *ctx = (entropy_ctx *) data;

    if( len > ctx->len )
        return( -1 );

    memcpy( buf, ctx->p, len );

    ctx->p += len;
    ctx->len -= len;

    return( 0 );
}
/* END_HEADER */

/* BEGIN_DEPENDENCIES
 * depends_on:MBEDTLS_HMAC_DRBG_C
 * END_DEPENDENCIES
 */

/* BEGIN_CASE */
void hmac_drbg_entropy_usage( int md_alg )
{
    unsigned char out[16];
    unsigned char buf[1024];
    const mbedtls_md_info_t *md_info;
    mbedtls_hmac_drbg_context ctx;
    entropy_ctx entropy;
    size_t last_len, i, reps = 10;

    mbedtls_hmac_drbg_init( &ctx );
    memset( buf, 0, sizeof( buf ) );
    memset( out, 0, sizeof( out ) );

    entropy.len = sizeof( buf );
    entropy.p = buf;

    md_info = mbedtls_md_info_from_type( md_alg );
    TEST_ASSERT( md_info != NULL );

    /* Init must use entropy */
    last_len = entropy.len;
    TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_entropy_func, &entropy,
                                 NULL, 0 ) == 0 );
    TEST_ASSERT( entropy.len < last_len );

    /* By default, PR is off and reseed_interval is large,
     * so the next few calls should not use entropy */
    last_len = entropy.len;
    for( i = 0; i < reps; i++ )
    {
        TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) - 4 ) == 0 );
        TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, out, sizeof( out ) - 4,
                                                buf, 16 ) == 0 );
    }
    TEST_ASSERT( entropy.len == last_len );

    /* While at it, make sure we didn't write past the requested length */
    TEST_ASSERT( out[sizeof( out ) - 4] == 0 );
    TEST_ASSERT( out[sizeof( out ) - 3] == 0 );
    TEST_ASSERT( out[sizeof( out ) - 2] == 0 );
    TEST_ASSERT( out[sizeof( out ) - 1] == 0 );

    /* Set reseed_interval to the number of calls done,
     * so the next call should reseed */
    mbedtls_hmac_drbg_set_reseed_interval( &ctx, 2 * reps );
    TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
    TEST_ASSERT( entropy.len < last_len );

    /* The new few calls should not reseed */
    last_len = entropy.len;
    for( i = 0; i < reps / 2; i++ )
    {
        TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
        TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, out, sizeof( out ) ,
                                                buf, 16 ) == 0 );
    }
    TEST_ASSERT( entropy.len == last_len );

    /* Now enable PR, so the next few calls should all reseed */
    mbedtls_hmac_drbg_set_prediction_resistance( &ctx, MBEDTLS_HMAC_DRBG_PR_ON );
    TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
    TEST_ASSERT( entropy.len < last_len );

    /* Finally, check setting entropy_len */
    mbedtls_hmac_drbg_set_entropy_len( &ctx, 42 );
    last_len = entropy.len;
    TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
    TEST_ASSERT( (int) last_len - entropy.len == 42 );

    mbedtls_hmac_drbg_set_entropy_len( &ctx, 13 );
    last_len = entropy.len;
    TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) ) == 0 );
    TEST_ASSERT( (int) last_len - entropy.len == 13 );

exit:
    mbedtls_hmac_drbg_free( &ctx );
}
/* END_CASE */

/* BEGIN_CASE depends_on:MBEDTLS_FS_IO */
void hmac_drbg_seed_file( int md_alg, char *path, int ret )
{
    const mbedtls_md_info_t *md_info;
    mbedtls_hmac_drbg_context ctx;

    mbedtls_hmac_drbg_init( &ctx );

    md_info = mbedtls_md_info_from_type( md_alg );
    TEST_ASSERT( md_info != NULL );

    TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, rnd_std_rand, NULL,
                                 NULL, 0 ) == 0 );

    TEST_ASSERT( mbedtls_hmac_drbg_write_seed_file( &ctx, path ) == ret );
    TEST_ASSERT( mbedtls_hmac_drbg_update_seed_file( &ctx, path ) == ret );

exit:
    mbedtls_hmac_drbg_free( &ctx );
}
/* END_CASE */

/* BEGIN_CASE */
void hmac_drbg_buf( int md_alg )
{
    unsigned char out[16];
    unsigned char buf[100];
    const mbedtls_md_info_t *md_info;
    mbedtls_hmac_drbg_context ctx;
    size_t i;

    mbedtls_hmac_drbg_init( &ctx );
    memset( buf, 0, sizeof( buf ) );
    memset( out, 0, sizeof( out ) );

    md_info = mbedtls_md_info_from_type( md_alg );
    TEST_ASSERT( md_info != NULL );
    TEST_ASSERT( mbedtls_hmac_drbg_seed_buf( &ctx, md_info, buf, sizeof( buf ) ) == 0 );

    /* Make sure it never tries to reseed (would segfault otherwise) */
    mbedtls_hmac_drbg_set_reseed_interval( &ctx, 3 );
    mbedtls_hmac_drbg_set_prediction_resistance( &ctx, MBEDTLS_HMAC_DRBG_PR_ON );

    for( i = 0; i < 30; i++ )
        TEST_ASSERT( mbedtls_hmac_drbg_random( &ctx, out, sizeof( out ) ) == 0 );

exit:
    mbedtls_hmac_drbg_free( &ctx );
}
/* END_CASE */

/* BEGIN_CASE */
void hmac_drbg_no_reseed( int md_alg,
                          char *entropy_hex, char *custom_hex,
                          char *add1_hex, char *add2_hex,
                          char *output_hex )
{
    unsigned char data[1024];
    unsigned char entropy[512];
    unsigned char custom[512];
    unsigned char add1[512];
    unsigned char add2[512];
    unsigned char output[512];
    unsigned char my_output[512];
    size_t custom_len, add1_len, add2_len, out_len;
    entropy_ctx p_entropy;
    const mbedtls_md_info_t *md_info;
    mbedtls_hmac_drbg_context ctx;

    mbedtls_hmac_drbg_init( &ctx );
    memset( my_output, 0, sizeof my_output );

    custom_len = unhexify( custom, custom_hex );
    add1_len = unhexify( add1, add1_hex );
    add2_len = unhexify( add2, add2_hex );
    out_len = unhexify( output, output_hex );
    p_entropy.len = unhexify( entropy, entropy_hex );
    p_entropy.p = entropy;

    md_info = mbedtls_md_info_from_type( md_alg );
    TEST_ASSERT( md_info != NULL );

    /* Test the simplified buffer-based variant */
    memcpy( data, entropy, p_entropy.len );
    memcpy( data + p_entropy.len, custom, custom_len );
    TEST_ASSERT( mbedtls_hmac_drbg_seed_buf( &ctx, md_info,
                                     data, p_entropy.len + custom_len ) == 0 );
    TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, out_len,
                                            add1, add1_len ) == 0 );
    TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, out_len,
                                            add2, add2_len ) == 0 );

    /* clear for second run */
    mbedtls_hmac_drbg_free( &ctx );

    TEST_ASSERT( memcmp( my_output, output, out_len ) == 0 );

    /* And now the normal entropy-based variant */
    TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_entropy_func, &p_entropy,
                                 custom, custom_len ) == 0 );
    TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, out_len,
                                            add1, add1_len ) == 0 );
    TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, out_len,
                                            add2, add2_len ) == 0 );
    TEST_ASSERT( memcmp( my_output, output, out_len ) == 0 );

exit:
    mbedtls_hmac_drbg_free( &ctx );
}
/* END_CASE */

/* BEGIN_CASE */
void hmac_drbg_nopr( int md_alg,
                     char *entropy_hex, char *custom_hex,
                     char *add1_hex, char *add2_hex, char *add3_hex,
                     char *output_hex )
{
    unsigned char entropy[512];
    unsigned char custom[512];
    unsigned char add1[512];
    unsigned char add2[512];
    unsigned char add3[512];
    unsigned char output[512];
    unsigned char my_output[512];
    size_t custom_len, add1_len, add2_len, add3_len, out_len;
    entropy_ctx p_entropy;
    const mbedtls_md_info_t *md_info;
    mbedtls_hmac_drbg_context ctx;

    mbedtls_hmac_drbg_init( &ctx );
    memset( my_output, 0, sizeof my_output );

    custom_len = unhexify( custom, custom_hex );
    add1_len = unhexify( add1, add1_hex );
    add2_len = unhexify( add2, add2_hex );
    add3_len = unhexify( add3, add3_hex );
    out_len = unhexify( output, output_hex );
    p_entropy.len = unhexify( entropy, entropy_hex );
    p_entropy.p = entropy;

    md_info = mbedtls_md_info_from_type( md_alg );
    TEST_ASSERT( md_info != NULL );

    TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_entropy_func, &p_entropy,
                                 custom, custom_len ) == 0 );
    TEST_ASSERT( mbedtls_hmac_drbg_reseed( &ctx, add1, add1_len ) == 0 );
    TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, out_len,
                                            add2, add2_len ) == 0 );
    TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, out_len,
                                            add3, add3_len ) == 0 );

    TEST_ASSERT( memcmp( my_output, output, out_len ) == 0 );

exit:
    mbedtls_hmac_drbg_free( &ctx );
}
/* END_CASE */

/* BEGIN_CASE */
void hmac_drbg_pr( int md_alg,
                   char *entropy_hex, char *custom_hex,
                   char *add1_hex, char *add2_hex,
                   char *output_hex )
{
    unsigned char entropy[512];
    unsigned char custom[512];
    unsigned char add1[512];
    unsigned char add2[512];
    unsigned char output[512];
    unsigned char my_output[512];
    size_t custom_len, add1_len, add2_len, out_len;
    entropy_ctx p_entropy;
    const mbedtls_md_info_t *md_info;
    mbedtls_hmac_drbg_context ctx;

    mbedtls_hmac_drbg_init( &ctx );
    memset( my_output, 0, sizeof my_output );

    custom_len = unhexify( custom, custom_hex );
    add1_len = unhexify( add1, add1_hex );
    add2_len = unhexify( add2, add2_hex );
    out_len = unhexify( output, output_hex );
    p_entropy.len = unhexify( entropy, entropy_hex );
    p_entropy.p = entropy;

    md_info = mbedtls_md_info_from_type( md_alg );
    TEST_ASSERT( md_info != NULL );

    TEST_ASSERT( mbedtls_hmac_drbg_seed( &ctx, md_info, mbedtls_entropy_func, &p_entropy,
                                 custom, custom_len ) == 0 );
    mbedtls_hmac_drbg_set_prediction_resistance( &ctx, MBEDTLS_HMAC_DRBG_PR_ON );
    TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, out_len,
                                            add1, add1_len ) == 0 );
    TEST_ASSERT( mbedtls_hmac_drbg_random_with_add( &ctx, my_output, out_len,
                                            add2, add2_len ) == 0 );

    TEST_ASSERT( memcmp( my_output, output, out_len ) == 0 );

exit:
    mbedtls_hmac_drbg_free( &ctx );
}
/* END_CASE */

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