mbedtls/tests/suites/test_suite_alignment.function

/* BEGIN_HEADER */
#include "../library/alignment.h"

#include <stdint.h>

#if defined(__clang__)
#pragma clang diagnostic ignored "-Wunreachable-code"
#endif
#include <stdio.h>

/*
 * Convert a string of the form "abcd" (case-insensitive) to a uint64_t.
 */
int parse_hex_string( char* hex_string, uint64_t *result )
{
    uint8_t raw[8];
    size_t olen;
    if ( mbedtls_test_unhexify(raw, sizeof(raw), hex_string, &olen) != 0 ) return 0;
    *result = 0;
    for ( size_t i = 0; i < olen; i++ )
    {
        if ( MBEDTLS_IS_BIG_ENDIAN ) {
            *result |= ((uint64_t)raw[i]) << ( i * 8 );
        }
        else
        {
            *result |= ((uint64_t)raw[i]) << ( (olen - i - 1) * 8 );
        }
    }
    return 1;
}

/* END_HEADER */

/* BEGIN_CASE */
void mbedtls_unaligned_access( int size, int offset )
{
    /* Define 64-bit aligned raw byte array */
    uint64_t raw[2];

    /* Populate with known data */
    uint8_t *x = (uint8_t *) raw;
    for ( size_t i = 0; i < sizeof(raw); i++ )
        x[i] = (uint8_t)i;

    TEST_ASSERT( size == 16 || size == 32 || size == 64 );

    uint64_t r = 0;
    switch ( size )
    {
        case 16:
            r = mbedtls_get_unaligned_uint16( x + offset );
            break;
        case 32:
            r = mbedtls_get_unaligned_uint32( x + offset );
            break;
        case 64:
            r = mbedtls_get_unaligned_uint64( x + offset );
            break;
    }

    /* Generate expected result */
    uint64_t expected = 0;
    for ( uint8_t i = 0; i < 8; i++ )
    {
        uint8_t shift;
        if ( MBEDTLS_IS_BIG_ENDIAN )
        {
            /*
            * Similar to little-endian case described below, but the shift needs
            * to be inverted
            */
            shift = 7 - ( i * 8 );
        } else {
            /* example for offset == 1:
            * expected = (( 1 + 0 ) << (0 * 8)) | (( 1 + 1 ) << (1 * 8)) | (( 1 + 2 ) << (2 * 8)))
            *          = (1 << 0) | (2 << 8) | (3 << 16) ...
            *          = 0x0807060504030201
            * x = { 0, 1, 2, 3, ... }
            * ie expected is the value that would be read from x on a LE system, when
            * byte swapping is not performed
            */
            shift = i * 8;
        }
        uint64_t b = offset + i;
        expected |= b << shift;
    }

    /* Mask out excess bits from expected result */
    switch ( size )
    {
        case 16:
            expected &= 0xffff;
            break;
        case 32:
            expected &= 0xffffffff;
            break;
    }

    TEST_EQUAL( r, expected );

    /* Write sentinel to the part of the array we will testing writing to */
    for ( size_t i = 0; i < (size_t) ( size / 8 ); i++ )
    {
        x[i + offset] = 0xff;
    }
    /*
        * Write back to the array with mbedtls_put_unaligned_uint16 and validate
        * that the array is unchanged as a result.
        */
    switch ( size )
    {
        case 16:
            mbedtls_put_unaligned_uint16( x + offset, r );
            break;
        case 32:
            mbedtls_put_unaligned_uint32( x + offset, r );
            break;
        case 64:
            mbedtls_put_unaligned_uint64( x + offset, r );
            break;
    }
    for ( size_t i = 0; i < sizeof(x); i++ )
    {
        TEST_EQUAL( x[i], (uint8_t)i );
    }
}
/* END_CASE */

/* BEGIN_CASE */
void mbedtls_byteswap( char* input_str, int size, char *expected_str )
{
    uint64_t input, expected;
    TEST_ASSERT( parse_hex_string( input_str, &input ) );
    TEST_ASSERT( parse_hex_string( expected_str, &expected ) );

    /* Check against expected result */
    uint64_t r = 0;
    switch ( size )
    {
        case 16:
            r = MBEDTLS_BSWAP16( input );
            break;
        case 32:
            r = MBEDTLS_BSWAP32( input );
            break;
        case 64:
            r = MBEDTLS_BSWAP64( input );
            break;
        default:
            TEST_ASSERT( ! "size must be 16, 32 or 64" );
    }
    TEST_EQUAL( r, expected );

    /*
     * Check byte by byte by extracting bytes from opposite ends of
     * input and r.
     */
    for ( size_t i = 0; i < (size_t)( size / 8 ); i++ )
    {
        size_t s1 = i * 8;
        size_t s2 = ( ( size / 8 - 1 ) - i ) * 8;
        uint64_t a = ( input & ( (uint64_t)0xff << s1 ) ) >> s1;
        uint64_t b = ( r & ( (uint64_t)0xff << s2 ) ) >> s2;
        TEST_EQUAL( a, b );
    }

    /* Check BSWAP(BSWAP(x)) == x */
    switch ( size )
    {
        case 16:
            r = MBEDTLS_BSWAP16( r );
            TEST_EQUAL( r, input & 0xffff );
            break;
        case 32:
            r = MBEDTLS_BSWAP32( r );
            TEST_EQUAL( r, input & 0xffffffff );
            break;
        case 64:
            r = MBEDTLS_BSWAP64( r );
            TEST_EQUAL( r, input );
            break;
    }
}
/* END_CASE */

/* BEGIN_CASE */
void get_byte()
{
    uint8_t data[16];

    for ( size_t i = 0; i < sizeof(data); i++ )
        data[i] = (uint8_t) i;

    uint64_t u64 = 0x0706050403020100;
    for ( size_t b = 0; b < 8 ; b++ )
    {
        uint8_t expected = b;
        uint8_t actual = b + 1;
        switch ( b )
        {
            case 0:
                actual = MBEDTLS_BYTE_0( u64 );
                break;
            case 1:
                actual = MBEDTLS_BYTE_1( u64 );
                break;
            case 2:
                actual = MBEDTLS_BYTE_2( u64 );
                break;
            case 3:
                actual = MBEDTLS_BYTE_3( u64 );
                break;
            case 4:
                actual = MBEDTLS_BYTE_4( u64 );
                break;
            case 5:
                actual = MBEDTLS_BYTE_5( u64 );
                break;
            case 6:
                actual = MBEDTLS_BYTE_6( u64 );
                break;
            case 7:
                actual = MBEDTLS_BYTE_7( u64 );
                break;
        }
        TEST_EQUAL( actual, expected );
    }

    uint32_t u32 = 0x03020100;
    for ( size_t b = 0; b < 4 ; b++ )
    {
        uint8_t expected = b;
        uint8_t actual = b + 1;
        switch ( b )
        {
            case 0:
                actual = MBEDTLS_BYTE_0( u32 );
                break;
            case 1:
                actual = MBEDTLS_BYTE_1( u32 );
                break;
            case 2:
                actual = MBEDTLS_BYTE_2( u32 );
                break;
            case 3:
                actual = MBEDTLS_BYTE_3( u32 );
                break;
        }
        TEST_EQUAL( actual, expected );
    }

    uint16_t u16 = 0x0100;
    for ( size_t b = 0; b < 2 ; b++ )
    {
        uint8_t expected = b;
        uint8_t actual = b + 1;
        switch ( b )
        {
            case 0:
                actual = MBEDTLS_BYTE_0( u16 );
                break;
            case 1:
                actual = MBEDTLS_BYTE_1( u16 );
                break;
        }
        TEST_EQUAL( actual, expected );
    }

    uint8_t u8 = 0x01;
    uint8_t actual = MBEDTLS_BYTE_0( u8 );
    TEST_EQUAL( actual, u8 );
}
/* END_CASE */

/* BEGIN_CASE */
void unaligned_access_endian_aware(int size, int offset, int big_endian )
{
    TEST_ASSERT( size == 16 || size == 24 || size == 32 || size == 64 );
    TEST_ASSERT( offset >= 0 && offset < 8 );

    /* Define 64-bit aligned raw byte array */
    uint64_t raw[2];
    /* Populate with known data: x == { 0, 1, 2, ... } */
    uint8_t *x = (uint8_t *) raw;
    for ( size_t i = 0; i < sizeof(raw); i++ )
        x[i] = (uint8_t) i;

    uint64_t read = 0;
    if ( big_endian )
    {
        switch ( size )
        {
            case 16:
                read = MBEDTLS_GET_UINT16_BE( x, offset );
                break;
            case 24:
                read = MBEDTLS_GET_UINT24_BE( x, offset );
                break;
            case 32:
                read = MBEDTLS_GET_UINT32_BE( x, offset );
                break;
            case 64:
                read = MBEDTLS_GET_UINT64_BE( x, offset );
                break;
        }
    }
    else
    {
        switch ( size )
        {
            case 16:
                read = MBEDTLS_GET_UINT16_LE( x, offset );
                break;
            case 24:
                read = MBEDTLS_GET_UINT24_LE( x, offset );
                break;
            case 32:
                read = MBEDTLS_GET_UINT32_LE( x, offset );
                break;
            case 64:
                read = MBEDTLS_GET_UINT64_LE( x, offset );
                break;
        }
    }

    /* Build up expected value byte by byte, in either big or little endian format */
    uint64_t expected = 0;
    for ( size_t i = 0; i < (size_t)(size / 8); i++ )
    {
        uint64_t b = x[i + offset];
        uint8_t shift = (big_endian) ? (8 * ((size / 8 - 1) - i)) : (8 * i);
        expected |= b << shift;
    }

    /* Verify read */
    TEST_EQUAL( read, expected );

    /* Test writing back to memory. First write sentiel */
    for ( size_t i = 0; i < (size_t)(size / 8); i++ )
    {
        x[i + offset] = 0xff;
    }
    /* Overwrite sentinel with endian-aware write macro */
    if ( big_endian )
    {
        switch ( size )
        {
            case 16:
                MBEDTLS_PUT_UINT16_BE( read, x, offset );
                break;
            case 24:
                MBEDTLS_PUT_UINT24_BE( read, x, offset );
                break;
            case 32:
                MBEDTLS_PUT_UINT32_BE( read, x, offset );
                break;
            case 64:
                MBEDTLS_PUT_UINT64_BE( read, x, offset );
                break;
        }
    }
    else
    {
        switch ( size )
        {
            case 16:
                MBEDTLS_PUT_UINT16_LE( read, x, offset );
                break;
                case 24:
                MBEDTLS_PUT_UINT24_LE( read, x, offset );
                break;
            case 32:
                MBEDTLS_PUT_UINT32_LE( read, x, offset );
                break;
            case 64:
                MBEDTLS_PUT_UINT64_LE( read, x, offset );
                break;
        }
    }

    /* Verify write - check memory is correct */
    for ( size_t i = 0; i < sizeof(raw); i++ )
        TEST_EQUAL( x[i], (uint8_t) i );
}
/* END_CASE */

/* BEGIN_CASE */
void mbedtls_is_big_endian()
{
    uint16_t check = 0x1234;
    uint8_t* p = (uint8_t*) &check;

    if ( MBEDTLS_IS_BIG_ENDIAN )
    {
        /* Big-endian: data stored MSB first, i.e. p == { 0x12, 0x34 } */
        TEST_EQUAL( p[0], 0x12 );
        TEST_EQUAL( p[1], 0x34 );
    }
    else
    {
        /* Little-endian: data stored LSB first, i.e. p == { 0x34, 0x12 } */
        TEST_EQUAL( p[0], 0x34 );
        TEST_EQUAL( p[1], 0x12 );
    }
}
/* END_CASE */