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Merge pull request #2104 from hanno-arm/iotssl-2071

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Check that integer types don't use padding bits in selftest
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Dave Rodgman 2022-04-11 17:26:08 +01:00 committed by GitHub
commit ed35887fc8
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1 changed files with 74 additions and 0 deletions
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74
programs/test/selftest.c
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@ -49,7 +49,9 @@
#include "mbedtls/ecjpake.h" #include "mbedtls/ecjpake.h"
#include "mbedtls/timing.h" #include "mbedtls/timing.h"
#include "mbedtls/nist_kw.h" #include "mbedtls/nist_kw.h"
#include "mbedtls/debug.h"
#include <limits.h>
#include <string.h> #include <string.h>
#if defined(MBEDTLS_PLATFORM_C) #if defined(MBEDTLS_PLATFORM_C)
@ -360,6 +362,78 @@ int main( int argc, char *argv[] )
mbedtls_exit( MBEDTLS_EXIT_FAILURE ); mbedtls_exit( MBEDTLS_EXIT_FAILURE );
} }
/*
* The C standard allows padding bits in the representation
* of standard integer types, but our code does currently not
* support them.
*
* Here we check that the underlying C implementation doesn't
* use padding bits, and fail cleanly if it does.
*
* The check works by casting the maximum value representable
* by a given integer type into the unpadded integer type of the
* same bit-width and checking that it agrees with the maximum value
* of that unpadded type. For example, for a 4-byte int,
* MAX_INT should be 0x7fffffff in int32_t. This assumes that
* CHAR_BIT == 8, which is checked in check_config.h.
*
* We assume that [u]intxx_t exist and that they don't
* have padding bits, as the standard requires.
*/
#define CHECK_PADDING_SIGNED(TYPE, NAME) \
do \
{ \
if( sizeof( TYPE ) == 2 || sizeof( TYPE ) == 4 || \
sizeof( TYPE ) == 8 ) { \
if( ( sizeof( TYPE ) == 2 && \
(int16_t) NAME ## _MAX != 0x7FFF ) || \
( sizeof( TYPE ) == 4 && \
(int32_t) NAME ## _MAX != 0x7FFFFFFF ) || \
( sizeof( TYPE ) == 8 && \
(int64_t) NAME ## _MAX != 0x7FFFFFFFFFFFFFFF ) ) \
{ \
mbedtls_printf( "Type '" #TYPE "' has padding bits\n" );\
mbedtls_exit( MBEDTLS_EXIT_FAILURE ); \
} \
} else { \
mbedtls_printf( "Padding checks only implemented for types of size 2, 4 or 8" \
" - cannot check type '" #TYPE "' of size %" MBEDTLS_PRINTF_SIZET "\n", \
sizeof( TYPE ) ); \
mbedtls_exit( MBEDTLS_EXIT_FAILURE ); \
} \
} while( 0 )
#define CHECK_PADDING_UNSIGNED(TYPE, NAME) \
do \
{ \
if( ( sizeof( TYPE ) == 2 && \
(uint16_t) NAME ## _MAX != 0xFFFF ) || \
( sizeof( TYPE ) == 4 && \
(uint32_t) NAME ## _MAX != 0xFFFFFFFF ) || \
( sizeof( TYPE ) == 8 && \
(uint64_t) NAME ## _MAX != 0xFFFFFFFFFFFFFFFF ) ) \
{ \
mbedtls_printf( "Type '" #TYPE "' has padding bits\n" ); \
mbedtls_exit( MBEDTLS_EXIT_FAILURE ); \
} \
} while( 0 )
CHECK_PADDING_SIGNED( short, SHRT );
CHECK_PADDING_SIGNED( int, INT );
CHECK_PADDING_SIGNED( long, LONG );
CHECK_PADDING_SIGNED( long long, LLONG );
CHECK_PADDING_SIGNED( ptrdiff_t, PTRDIFF );
CHECK_PADDING_UNSIGNED( unsigned short, USHRT );
CHECK_PADDING_UNSIGNED( unsigned, UINT );
CHECK_PADDING_UNSIGNED( unsigned long, ULONG );
CHECK_PADDING_UNSIGNED( unsigned long long, ULLONG );
CHECK_PADDING_UNSIGNED( size_t, SIZE );
#undef CHECK_PADDING_SIGNED
#undef CHECK_PADDING_UNSIGNED
/* /*
* Make sure we have a snprintf that correctly zero-terminates * Make sure we have a snprintf that correctly zero-terminates
*/ */