Merge pull request #1156 from Ryan-Everett-arm/key-derivation-buffer-protection
Add buffer copying to the Key Derivation API
diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index 36601f6..ca10c14 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -5854,10 +5854,12 @@
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) {
@@ -5865,13 +5867,6 @@
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
@@ -5881,6 +5876,16 @@
* 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(BUILTIN_ALG_ANY_HKDF)
@@ -5914,7 +5919,10 @@
{
(void) kdf_alg;
- return PSA_ERROR_BAD_STATE;
+ status = PSA_ERROR_BAD_STATE;
+ LOCAL_OUTPUT_FREE(output_external, output);
+
+ return status;
}
exit:
@@ -5926,8 +5934,12 @@
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;
}
@@ -6907,12 +6919,12 @@
{
psa_status_t status = PSA_SUCCESS;
if (input_len > PSA_HASH_BLOCK_LENGTH(hash_alg)) {
- status = psa_hash_compute(hash_alg, input, input_len, output,
- PSA_HMAC_MAX_HASH_BLOCK_SIZE, output_len);
- } else {
+ return psa_hash_compute(hash_alg, input, input_len, output,
+ PSA_HMAC_MAX_HASH_BLOCK_SIZE, output_len);
+ } else if (input_len > 0) {
memcpy(output, input, input_len);
- *output_len = PSA_HASH_BLOCK_LENGTH(hash_alg);
}
+ *output_len = PSA_HASH_BLOCK_LENGTH(hash_alg);
return status;
}
#endif /* MBEDTLS_PSA_BUILTIN_ALG_PBKDF2_HMAC */
@@ -7146,12 +7158,22 @@
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_integer(
diff --git a/tests/scripts/generate_psa_wrappers.py b/tests/scripts/generate_psa_wrappers.py
index bb372f5..c65603b 100755
--- a/tests/scripts/generate_psa_wrappers.py
+++ b/tests/scripts/generate_psa_wrappers.py
@@ -145,6 +145,9 @@
# 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 14da8ad..728afed 100644
--- a/tests/src/psa_test_wrappers.c
+++ b/tests/src/psa_test_wrappers.c
@@ -646,7 +646,13 @@
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;
}
@@ -688,7 +694,13 @@
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;
}