generate/derive key ext: pass method_data_length rather than method_length
Instead of passing the size of the whole structure, just pass the data
length and let the implementation worry about adding the size of the
structure. The intent with passing the structure size was to allow
the client code in a client-server implementation to know nothing
about the structure and just copy the bytes to the server. But that was not
really a useful consideration since the application has to know the
structure layout, so it has to be available in the client implementation's
headers. Passing the method data length makes life simpler for everyone by
not having to worry about possible padding at the end of the structure, and
removes a potential error condition
(method_length < sizeof(psa_key_generation_method_t)).
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 98823de..3c328c4 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -6027,12 +6027,12 @@
static int psa_key_generation_method_is_default(
const psa_key_generation_method_t *method,
- size_t method_length)
+ size_t method_data_length)
{
- if (method_length != sizeof(*method)) {
+ if (method->flags != 0) {
return 0;
}
- if (method->flags != 0) {
+ if (method_data_length != 0) {
return 0;
}
return 1;
@@ -6042,7 +6042,7 @@
const psa_key_attributes_t *attributes,
psa_key_derivation_operation_t *operation,
const psa_key_generation_method_t *method,
- size_t method_length,
+ size_t method_data_length,
mbedtls_svc_key_id_t *key)
{
psa_status_t status;
@@ -6057,10 +6057,7 @@
return PSA_ERROR_INVALID_ARGUMENT;
}
- if (method_length < sizeof(*method)) {
- return PSA_ERROR_INVALID_ARGUMENT;
- }
- if (!psa_key_generation_method_is_default(method, method_length)) {
+ if (!psa_key_generation_method_is_default(method, method_data_length)) {
return PSA_ERROR_INVALID_ARGUMENT;
}
@@ -6100,10 +6097,9 @@
psa_key_derivation_operation_t *operation,
mbedtls_svc_key_id_t *key)
{
- return psa_key_derivation_output_key_ext(
- attributes, operation,
- &default_method, sizeof(default_method),
- key);
+ return psa_key_derivation_output_key_ext(attributes, operation,
+ &default_method, 0,
+ key);
}
@@ -7501,7 +7497,7 @@
psa_status_t psa_generate_key_internal(
const psa_key_attributes_t *attributes,
- const psa_key_generation_method_t *method, size_t method_length,
+ const psa_key_generation_method_t *method, size_t method_data_length,
uint8_t *key_buffer, size_t key_buffer_size, size_t *key_buffer_length)
{
psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
@@ -7509,7 +7505,7 @@
/* Only used for RSA */
(void) method;
- (void) method_length;
+ (void) method_data_length;
if ((attributes->domain_parameters == NULL) &&
(attributes->domain_parameters_size != 0)) {
@@ -7536,9 +7532,8 @@
* that mbedtls_psa_rsa_generate_key() gets e via a new
* parameter instead. */
psa_key_attributes_t override_attributes = *attributes;
- if (method_length > sizeof(*method)) {
- override_attributes.domain_parameters_size =
- method_length - offsetof(psa_key_generation_method_t, data);
+ if (method_data_length != 0) {
+ override_attributes.domain_parameters_size = method_data_length;
override_attributes.domain_parameters = (uint8_t *) &method->data;
}
return mbedtls_psa_rsa_generate_key(&override_attributes,
@@ -7575,7 +7570,7 @@
psa_status_t psa_generate_key_ext(const psa_key_attributes_t *attributes,
const psa_key_generation_method_t *method,
- size_t method_length,
+ size_t method_data_length,
mbedtls_svc_key_id_t *key)
{
psa_status_t status;
@@ -7596,10 +7591,6 @@
return PSA_ERROR_INVALID_ARGUMENT;
}
- if (method_length < sizeof(*method)) {
- return PSA_ERROR_INVALID_ARGUMENT;
- }
-
#if defined(PSA_WANT_KEY_TYPE_RSA_KEY_PAIR_GENERATE)
if (attributes->core.type == PSA_KEY_TYPE_RSA_KEY_PAIR) {
if (method->flags != 0) {
@@ -7607,7 +7598,7 @@
}
} else
#endif
- if (!psa_key_generation_method_is_default(method, method_length)) {
+ if (!psa_key_generation_method_is_default(method, method_data_length)) {
return PSA_ERROR_INVALID_ARGUMENT;
}
@@ -7648,7 +7639,7 @@
}
status = psa_driver_wrapper_generate_key(attributes,
- method, method_length,
+ method, method_data_length,
slot->key.data, slot->key.bytes,
&slot->key.bytes);
if (status != PSA_SUCCESS) {
@@ -7670,7 +7661,7 @@
mbedtls_svc_key_id_t *key)
{
return psa_generate_key_ext(attributes,
- &default_method, sizeof(default_method),
+ &default_method, 0,
key);
}