Merge pull request #1179 from Ryan-Everett-arm/key-derivation-buffer-protection-backport
[Backport] Add buffer copying to the Key Derivation API
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 78737fd..d30462b 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -4413,10 +4413,12 @@
psa_status_t psa_key_derivation_output_bytes(
psa_key_derivation_operation_t *operation,
- uint8_t *output,
+ uint8_t *output_external,
size_t output_length)
{
psa_status_t status;
+ LOCAL_OUTPUT_DECLARE(output_external, output);
+
psa_algorithm_t kdf_alg = psa_key_derivation_get_kdf_alg(operation);
if (operation->alg == 0) {
@@ -4424,13 +4426,6 @@
return PSA_ERROR_BAD_STATE;
}
- if (output_length > operation->capacity) {
- operation->capacity = 0;
- /* Go through the error path to wipe all confidential data now
- * that the operation object is useless. */
- status = PSA_ERROR_INSUFFICIENT_DATA;
- goto exit;
- }
if (output_length == 0 && operation->capacity == 0) {
/* Edge case: this is a finished operation, and 0 bytes
* were requested. The right error in this case could
@@ -4440,6 +4435,15 @@
* output_length > 0. */
return PSA_ERROR_INSUFFICIENT_DATA;
}
+
+ LOCAL_OUTPUT_ALLOC(output_external, output_length, output);
+ if (output_length > operation->capacity) {
+ operation->capacity = 0;
+ /* Go through the error path to wipe all confidential data now
+ * that the operation object is useless. */
+ status = PSA_ERROR_INSUFFICIENT_DATA;
+ goto exit;
+ }
operation->capacity -= output_length;
#if defined(MBEDTLS_PSA_BUILTIN_ALG_HKDF)
@@ -4461,7 +4465,10 @@
* MBEDTLS_PSA_BUILTIN_ALG_TLS12_PSK_TO_MS */
{
(void) kdf_alg;
- return PSA_ERROR_BAD_STATE;
+ status = PSA_ERROR_BAD_STATE;
+ LOCAL_OUTPUT_FREE(output_external, output);
+
+ return status;
}
exit:
@@ -4473,8 +4480,12 @@
psa_algorithm_t alg = operation->alg;
psa_key_derivation_abort(operation);
operation->alg = alg;
- memset(output, '!', output_length);
+ if (output != NULL) {
+ memset(output, '!', output_length);
+ }
}
+
+ LOCAL_OUTPUT_FREE(output_external, output);
return status;
}
@@ -5025,12 +5036,22 @@
psa_status_t psa_key_derivation_input_bytes(
psa_key_derivation_operation_t *operation,
psa_key_derivation_step_t step,
- const uint8_t *data,
+ const uint8_t *data_external,
size_t data_length)
{
- return psa_key_derivation_input_internal(operation, step,
- PSA_KEY_TYPE_NONE,
- data, data_length);
+ psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
+ LOCAL_INPUT_DECLARE(data_external, data);
+
+ LOCAL_INPUT_ALLOC(data_external, data_length, data);
+
+ status = psa_key_derivation_input_internal(operation, step,
+ PSA_KEY_TYPE_NONE,
+ data, data_length);
+#if defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS)
+exit:
+#endif
+ LOCAL_INPUT_FREE(data_external, data);
+ return status;
}
psa_status_t psa_key_derivation_input_key(
diff --git a/tests/scripts/generate_psa_wrappers.py b/tests/scripts/generate_psa_wrappers.py
index 96b8995..0b7cf44 100755
--- a/tests/scripts/generate_psa_wrappers.py
+++ b/tests/scripts/generate_psa_wrappers.py
@@ -153,6 +153,9 @@
# Proof-of-concept: just instrument one function for now
if function_name == 'psa_cipher_encrypt':
return True
+ if function_name in ('psa_key_derivation_output_bytes',
+ 'psa_key_derivation_input_bytes'):
+ return True
if function_name in ('psa_import_key',
'psa_export_key',
'psa_export_public_key'):
diff --git a/tests/src/psa_test_wrappers.c b/tests/src/psa_test_wrappers.c
index 5382d03..c85b65d 100644
--- a/tests/src/psa_test_wrappers.c
+++ b/tests/src/psa_test_wrappers.c
@@ -472,7 +472,13 @@
const uint8_t *arg2_data,
size_t arg3_data_length)
{
+#if defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS)
+ MBEDTLS_TEST_MEMORY_POISON(arg2_data, arg3_data_length);
+#endif /* defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS) */
psa_status_t status = (psa_key_derivation_input_bytes)(arg0_operation, arg1_step, arg2_data, arg3_data_length);
+#if defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS)
+ MBEDTLS_TEST_MEMORY_UNPOISON(arg2_data, arg3_data_length);
+#endif /* defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS) */
return status;
}
@@ -504,7 +510,13 @@
uint8_t *arg1_output,
size_t arg2_output_length)
{
+#if defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS)
+ MBEDTLS_TEST_MEMORY_POISON(arg1_output, arg2_output_length);
+#endif /* defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS) */
psa_status_t status = (psa_key_derivation_output_bytes)(arg0_operation, arg1_output, arg2_output_length);
+#if defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS)
+ MBEDTLS_TEST_MEMORY_UNPOISON(arg1_output, arg2_output_length);
+#endif /* defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS) */
return status;
}