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Add PSA Crypto driver delegation for hashing functions #4043

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Add PSA Crypto driver delegation for hashing functions #4043

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db1936b
Splice in driver delegation for hashing functions
stevew817 Jan 15, 2021
1b04bb3
Add back the dummy integer for easier initialisation
stevew817 Jan 15, 2021
2618741
Move up invalid context check in clone_hash
stevew817 Jan 15, 2021
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3 changes: 3 additions & 0 deletions ChangeLog.d/psa-crypto-hash-acceleration.txt
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Original file line number Diff line number Diff line change
@@ -0,0 +1,3 @@
Features
* Hashing operations executed through the PSA API can now be accelerated
with a PSA Crypto driver.
5 changes: 3 additions & 2 deletions include/psa/crypto_struct.h
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Original file line number Diff line number Diff line change
Expand Up @@ -90,9 +90,10 @@ typedef struct {
struct psa_hash_operation_s
{
psa_algorithm_t alg;
unsigned int mbedtls_in_use : 1; /* Indicates mbed TLS is handling the operation. */
union
{
unsigned dummy; /* Make the union non-empty even with no supported algorithms. */
psa_operation_driver_context_t driver;
#if defined(MBEDTLS_MD2_C)
mbedtls_md2_context md2;
#endif
Expand All @@ -117,7 +118,7 @@ struct psa_hash_operation_s
} ctx;
};

#define PSA_HASH_OPERATION_INIT {0, {0}}
#define PSA_HASH_OPERATION_INIT {0, 0, {0}}
static inline struct psa_hash_operation_s psa_hash_operation_init( void )
{
const struct psa_hash_operation_s v = PSA_HASH_OPERATION_INIT;
Expand Down
119 changes: 98 additions & 21 deletions library/psa_crypto.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2537,6 +2537,20 @@ static const mbedtls_md_info_t *mbedtls_md_info_from_psa( psa_algorithm_t alg )

psa_status_t psa_hash_abort( psa_hash_operation_t *operation )
{
if( operation->alg == 0 )
{
/* The object has (apparently) been initialized but it is not
* in use. It's ok to call abort on such an object, and there's
* nothing to do. */
return( PSA_SUCCESS );
}

if( operation->mbedtls_in_use == 0 )
{
psa_driver_wrapper_hash_abort( &operation->ctx.driver );
goto exit;
}

switch( operation->alg )
{
case 0:
Expand Down Expand Up @@ -2592,13 +2606,16 @@ psa_status_t psa_hash_abort( psa_hash_operation_t *operation )
default:
return( PSA_ERROR_BAD_STATE );
}

exit:
operation->alg = 0;
return( PSA_SUCCESS );
}

psa_status_t psa_hash_setup( psa_hash_operation_t *operation,
psa_algorithm_t alg )
{
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

/* A context must be freshly initialized before it can be set up. */
Expand All @@ -2607,6 +2624,17 @@ psa_status_t psa_hash_setup( psa_hash_operation_t *operation,
return( PSA_ERROR_BAD_STATE );
}

operation->mbedtls_in_use = 0;
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@ronald-cron-arm ronald-cron-arm Jan 22, 2021 •
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This is not aligned with the organization of the PSA implementation with respect to the PSA driver interface that we are currently trying to move to. The code organization is described in the psa-crypto-implementation-structure.md document in PR #3933 and an example of its application for multi-part operation can be found here (for ciphers).
Thus this is likely that this PR will need some significant refactoring. It is also probably better to not start any refactoring before PR #3933 is merged.

status = psa_driver_wrapper_hash_setup( &operation->ctx.driver,
alg );
if( status != PSA_ERROR_NOT_SUPPORTED )
{
goto exit;
}

/* fell through, try mbed TLS functions */
operation->mbedtls_in_use = 1;

switch( alg )
{
#if defined(MBEDTLS_PSA_BUILTIN_ALG_MD2)
Expand Down Expand Up @@ -2668,24 +2696,39 @@ psa_status_t psa_hash_setup( psa_hash_operation_t *operation,
PSA_ERROR_NOT_SUPPORTED :
PSA_ERROR_INVALID_ARGUMENT );
}
if( ret == 0 )
status = mbedtls_to_psa_error( ret );

exit:
if( status == PSA_SUCCESS )
operation->alg = alg;
else
psa_hash_abort( operation );
return( mbedtls_to_psa_error( ret ) );
return( status );
}

psa_status_t psa_hash_update( psa_hash_operation_t *operation,
const uint8_t *input,
size_t input_length )
{
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;

if ( operation->alg == 0 )
return( PSA_ERROR_BAD_STATE );

/* Don't require hash implementations to behave correctly on a
* zero-length input, which may have an invalid pointer. */
if( input_length == 0 )
return( PSA_SUCCESS );

if( operation->mbedtls_in_use == 0 )
{
status = psa_driver_wrapper_hash_update( &operation->ctx.driver,
input,
input_length );
goto exit;
}

switch( operation->alg )
{
#if defined(MBEDTLS_PSA_BUILTIN_ALG_MD2)
Expand Down Expand Up @@ -2747,20 +2790,26 @@ psa_status_t psa_hash_update( psa_hash_operation_t *operation,
return( PSA_ERROR_BAD_STATE );
}

if( ret != 0 )
status = mbedtls_to_psa_error( ret );

exit:
if( status != PSA_SUCCESS )
psa_hash_abort( operation );
return( mbedtls_to_psa_error( ret ) );
return( status );
}

psa_status_t psa_hash_finish( psa_hash_operation_t *operation,
uint8_t *hash,
size_t hash_size,
size_t *hash_length )
{
psa_status_t status;
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t actual_hash_length = PSA_HASH_SIZE( operation->alg );

if ( operation->alg == 0 )
return( PSA_ERROR_BAD_STATE );

/* Fill the output buffer with something that isn't a valid hash
* (barring an attack on the hash and deliberately-crafted input),
* in case the caller doesn't check the return status properly. */
Expand All @@ -2776,6 +2825,15 @@ psa_status_t psa_hash_finish( psa_hash_operation_t *operation,
goto exit;
}

if( operation->mbedtls_in_use == 0 )
{
status = psa_driver_wrapper_hash_finish( &operation->ctx.driver,
hash,
hash_size,
hash_length );
goto exit;
}

switch( operation->alg )
{
#if defined(MBEDTLS_PSA_BUILTIN_ALG_MD2)
Expand Down Expand Up @@ -2867,6 +2925,12 @@ psa_status_t psa_hash_compute( psa_algorithm_t alg,
psa_hash_operation_t operation = PSA_HASH_OPERATION_INIT;
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;

status = psa_driver_wrapper_hash_compute( alg, input, input_length,
hash, hash_size, hash_length );

if( status != PSA_ERROR_NOT_SUPPORTED )
return( status );

*hash_length = hash_size;
status = psa_hash_setup( &operation, alg );
if( status != PSA_SUCCESS )
Expand All @@ -2890,33 +2954,44 @@ psa_status_t psa_hash_compare( psa_algorithm_t alg,
const uint8_t *input, size_t input_length,
const uint8_t *hash, size_t hash_length )
{
psa_hash_operation_t operation = PSA_HASH_OPERATION_INIT;
uint8_t actual_hash[MBEDTLS_MD_MAX_SIZE];
size_t actual_hash_length;
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;

status = psa_hash_setup( &operation, alg );
if( status != PSA_SUCCESS )
goto exit;
status = psa_hash_update( &operation, input, input_length );
if( status != PSA_SUCCESS )
goto exit;
status = psa_hash_verify( &operation, hash, hash_length );
if( status != PSA_SUCCESS )
goto exit;
status = psa_hash_compute( alg, input, input_length,
actual_hash, sizeof(actual_hash),
&actual_hash_length );

exit:
if( status == PSA_SUCCESS )
status = psa_hash_abort( &operation );
else
psa_hash_abort( &operation );
return( status );
if( status != PSA_SUCCESS )
return( status );
if( actual_hash_length != hash_length )
return( PSA_ERROR_INVALID_SIGNATURE );
if( safer_memcmp( hash, actual_hash, actual_hash_length ) != 0 )
return( PSA_ERROR_INVALID_SIGNATURE );
return( PSA_SUCCESS );
}

psa_status_t psa_hash_clone( const psa_hash_operation_t *source_operation,
psa_hash_operation_t *target_operation )
{
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;

if( target_operation->alg != 0 )
return( PSA_ERROR_BAD_STATE );

#if defined(MBEDTLS_PSA_CRYPTO_DRIVERS)
if ( source_operation->mbedtls_in_use == 0 )
{
status = psa_driver_wrapper_hash_clone( &source_operation->ctx.driver,
&target_operation->ctx.driver);
if ( status == PSA_SUCCESS )
goto exit;
/* Cloning a hash operation using a driver needs to succeed since only
* that specific driver knows the context structure. */
return( status );
}
#endif

switch( source_operation->alg )
{
case 0:
Expand Down Expand Up @@ -2979,6 +3054,8 @@ psa_status_t psa_hash_clone( const psa_hash_operation_t *source_operation,
return( PSA_ERROR_NOT_SUPPORTED );
}

exit:
target_operation->mbedtls_in_use = source_operation->mbedtls_in_use;
target_operation->alg = source_operation->alg;
return( PSA_SUCCESS );
}
Expand Down
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