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Merged
merged 1 commit into from
Feb 18, 2019
Merged

psa: Check generator validity before read #57

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25 changes: 21 additions & 4 deletions library/psa_crypto.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3621,6 +3621,12 @@ psa_status_t psa_generator_abort( psa_crypto_generator_t *generator )
psa_status_t psa_get_generator_capacity(const psa_crypto_generator_t *generator,
size_t *capacity)
{
if( generator->alg == 0 )
{
/* This is a blank generator. */
return PSA_ERROR_BAD_STATE;
}

*capacity = generator->capacity;
return( PSA_SUCCESS );
}
Expand Down Expand Up @@ -3850,6 +3856,12 @@ psa_status_t psa_generator_read( psa_crypto_generator_t *generator,
{
psa_status_t status;

if( generator->alg == 0 )
{
/* This is a blank generator. */
return PSA_ERROR_BAD_STATE;
}

if( output_length > generator->capacity )
{
generator->capacity = 0;
Expand All @@ -3858,11 +3870,10 @@ psa_status_t psa_generator_read( psa_crypto_generator_t *generator,
status = PSA_ERROR_INSUFFICIENT_DATA;
goto exit;
}
if( output_length == 0 &&
generator->capacity == 0 && generator->alg == 0 )
if( output_length == 0 && generator->capacity == 0 )
{
/* Edge case: this is a blank or finished generator, and 0
* bytes were requested. The right error in this case could
/* Edge case: this is a finished generator, and 0 bytes
* were requested. The right error in this case could
* be either INSUFFICIENT_CAPACITY or BAD_STATE. Return
* INSUFFICIENT_CAPACITY, which is right for a finished
* generator, for consistency with the case when
Expand Down Expand Up @@ -3911,7 +3922,13 @@ psa_status_t psa_generator_read( psa_crypto_generator_t *generator,
exit:
if( status != PSA_SUCCESS )
{
/* Preserve the algorithm upon errors, but clear all sensitive state.
* This allows us to differentiate between exhausted generators and
* blank generators, so we can return PSA_ERROR_BAD_STATE on blank
* generators. */
psa_algorithm_t alg = generator->alg;
psa_generator_abort( generator );
generator->alg = alg;
memset( output, '!', output_length );
}
return( status );
Expand Down
22 changes: 11 additions & 11 deletions tests/suites/test_suite_psa_crypto.function
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Original file line number Diff line number Diff line change
Expand Up @@ -3519,13 +3519,13 @@ void crypto_generator_init( )

memset( &zero, 0, sizeof( zero ) );

/* A default generator should have no capacity. */
PSA_ASSERT( psa_get_generator_capacity( &func, &capacity ) );
TEST_EQUAL( capacity, 0 );
PSA_ASSERT( psa_get_generator_capacity( &init, &capacity ) );
TEST_EQUAL( capacity, 0 );
PSA_ASSERT( psa_get_generator_capacity( &zero, &capacity ) );
TEST_EQUAL( capacity, 0 );
/* A default generator should not be able to report its capacity. */
TEST_EQUAL( psa_get_generator_capacity( &func, &capacity ),
PSA_ERROR_BAD_STATE );
TEST_EQUAL( psa_get_generator_capacity( &init, &capacity ),
PSA_ERROR_BAD_STATE );
TEST_EQUAL( psa_get_generator_capacity( &zero, &capacity ),
PSA_ERROR_BAD_STATE );

/* A default generator should be abortable without error. */
PSA_ASSERT( psa_generator_abort(&func) );
Expand Down Expand Up @@ -3632,18 +3632,18 @@ void test_derive_invalid_generator_tests( )
psa_crypto_generator_t generator = PSA_CRYPTO_GENERATOR_INIT;

TEST_ASSERT( psa_generator_read( &generator, output_buffer, buffer_size )
== PSA_ERROR_INSUFFICIENT_DATA ); // should be PSA_ERROR_BAD_STATE:#183
== PSA_ERROR_BAD_STATE );

TEST_ASSERT( psa_get_generator_capacity( &generator, &capacity )
== PSA_SUCCESS ); // should be PSA_ERROR_BAD_STATE:#183
== PSA_ERROR_BAD_STATE );

PSA_ASSERT( psa_generator_abort( &generator ) );

TEST_ASSERT( psa_generator_read( &generator, output_buffer, buffer_size )
== PSA_ERROR_INSUFFICIENT_DATA ); // should be PSA_ERROR_BAD_STATE:#183
== PSA_ERROR_BAD_STATE );

TEST_ASSERT( psa_get_generator_capacity( &generator, &capacity )
== PSA_SUCCESS );// should be PSA_ERROR_BAD_STATE:#183
== PSA_ERROR_BAD_STATE );

exit:
psa_generator_abort( &generator );
Expand Down