Merge pull request #1137 from Ryan-Everett-arm/key-management-buffer-protection

Add buffer copying to the Key Management API

library/psa_crypto.c

@@ -1599,13 +1599,14 @@ psa_status_t psa_export_key_internal(
 }
 
 psa_status_t psa_export_key(mbedtls_svc_key_id_t key,
-                            uint8_t *data,
+                            uint8_t *data_external,
                             size_t data_size,
                             size_t *data_length)
 {
     psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
     psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
     psa_key_slot_t *slot;
+    LOCAL_OUTPUT_DECLARE(data_external, data);
 
     /* Reject a zero-length output buffer now, since this can never be a
      * valid key representation. This way we know that data must be a valid
@@ -1630,15 +1631,20 @@ psa_status_t psa_export_key(mbedtls_svc_key_id_t key,
         return status;
     }
 
+    LOCAL_OUTPUT_ALLOC(data_external, data_size, data);
+
     psa_key_attributes_t attributes = {
         .core = slot->attr
     };
     status = psa_driver_wrapper_export_key(&attributes,
                                            slot->key.data, slot->key.bytes,
                                            data, data_size, data_length);
-
+#if defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS)
+exit:
+#endif
     unlock_status = psa_unlock_key_slot(slot);
 
+    LOCAL_OUTPUT_FREE(data_external, data);
     return (status == PSA_SUCCESS) ? unlock_status : status;
 }
 
@@ -1710,7 +1716,7 @@ psa_status_t psa_export_public_key_internal(
 }
 
 psa_status_t psa_export_public_key(mbedtls_svc_key_id_t key,
-                                   uint8_t *data,
+                                   uint8_t *data_external,
                                    size_t data_size,
                                    size_t *data_length)
 {
@@ -1718,6 +1724,7 @@ psa_status_t psa_export_public_key(mbedtls_svc_key_id_t key,
     psa_status_t unlock_status = PSA_ERROR_CORRUPTION_DETECTED;
     psa_key_slot_t *slot;
     psa_key_attributes_t attributes;
+    LOCAL_OUTPUT_DECLARE(data_external, data);
 
     /* Reject a zero-length output buffer now, since this can never be a
      * valid key representation. This way we know that data must be a valid
@@ -1738,6 +1745,8 @@ psa_status_t psa_export_public_key(mbedtls_svc_key_id_t key,
         return status;
     }
 
+    LOCAL_OUTPUT_ALLOC(data_external, data_size, data);
+
     if (!PSA_KEY_TYPE_IS_ASYMMETRIC(slot->attr.type)) {
         status = PSA_ERROR_INVALID_ARGUMENT;
         goto exit;
@@ -1753,6 +1762,7 @@ psa_status_t psa_export_public_key(mbedtls_svc_key_id_t key,
 exit:
     unlock_status = psa_unlock_key_slot(slot);
 
+    LOCAL_OUTPUT_FREE(data_external, data);
     return (status == PSA_SUCCESS) ? unlock_status : status;
 }
 
@@ -2199,11 +2209,12 @@ rsa_exit:
 }
 
 psa_status_t psa_import_key(const psa_key_attributes_t *attributes,
-                            const uint8_t *data,
+                            const uint8_t *data_external,
                             size_t data_length,
                             mbedtls_svc_key_id_t *key)
 {
     psa_status_t status;
+    LOCAL_INPUT_DECLARE(data_external, data);
     psa_key_slot_t *slot = NULL;
     psa_se_drv_table_entry_t *driver = NULL;
     size_t bits;
@@ -2223,6 +2234,8 @@ psa_status_t psa_import_key(const psa_key_attributes_t *attributes,
         return PSA_ERROR_NOT_SUPPORTED;
     }
 
+    LOCAL_INPUT_ALLOC(data_external, data_length, data);
+
     status = psa_start_key_creation(PSA_KEY_CREATION_IMPORT, attributes,
                                     &slot, &driver);
     if (status != PSA_SUCCESS) {
@@ -2277,6 +2290,7 @@ psa_status_t psa_import_key(const psa_key_attributes_t *attributes,
 
     status = psa_finish_key_creation(slot, driver, key);
 exit:
+    LOCAL_INPUT_FREE(data_external, data);
     if (status != PSA_SUCCESS) {
         psa_fail_key_creation(slot, driver);
     }

tests/include/test/psa_crypto_helpers.h

@@ -16,13 +16,6 @@
 #include <psa/crypto.h>
 #endif
 
-#include "test/psa_test_wrappers.h"
-
-#if defined(MBEDTLS_TEST_HOOKS) && defined(MBEDTLS_PSA_CRYPTO_C) \
-    && defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS)
-#include "test/psa_memory_poisoning_wrappers.h"
-#endif
-
 #if defined(MBEDTLS_PSA_CRYPTO_C)
 /** Initialize the PSA Crypto subsystem. */
 #define PSA_INIT() PSA_ASSERT(psa_crypto_init())

tests/scripts/generate_psa_wrappers.py

@@ -145,6 +145,10 @@ class PSAWrapperGenerator(c_wrapper_generator.Base):
         # Proof-of-concept: just instrument one function for now
         if function_name == 'psa_cipher_encrypt':
             return True
+        if function_name in ('psa_import_key',
+                             'psa_export_key',
+                             'psa_export_public_key'):
+            return True
         if function_name in ('psa_sign_message',
                              'psa_verify_message',
                              'psa_sign_hash',

tests/src/psa_test_wrappers.c

@@ -435,7 +435,13 @@ psa_status_t mbedtls_test_wrap_psa_export_key(
     size_t arg2_data_size,
     size_t *arg3_data_length)
 {
+#if defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS)
+    MBEDTLS_TEST_MEMORY_POISON(arg1_data, arg2_data_size);
+#endif /* defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS) */
     psa_status_t status = (psa_export_key)(arg0_key, arg1_data, arg2_data_size, arg3_data_length);
+#if defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS)
+    MBEDTLS_TEST_MEMORY_UNPOISON(arg1_data, arg2_data_size);
+#endif /* defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS) */
     return status;
 }
 
@@ -446,7 +452,13 @@ psa_status_t mbedtls_test_wrap_psa_export_public_key(
     size_t arg2_data_size,
     size_t *arg3_data_length)
 {
+#if defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS)
+    MBEDTLS_TEST_MEMORY_POISON(arg1_data, arg2_data_size);
+#endif /* defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS) */
     psa_status_t status = (psa_export_public_key)(arg0_key, arg1_data, arg2_data_size, arg3_data_length);
+#if defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS)
+    MBEDTLS_TEST_MEMORY_UNPOISON(arg1_data, arg2_data_size);
+#endif /* defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS) */
     return status;
 }
 
@@ -566,7 +578,13 @@ psa_status_t mbedtls_test_wrap_psa_import_key(
     size_t arg2_data_length,
     mbedtls_svc_key_id_t *arg3_key)
 {
+#if defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS)
+    MBEDTLS_TEST_MEMORY_POISON(arg1_data, arg2_data_length);
+#endif /* defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS) */
     psa_status_t status = (psa_import_key)(arg0_attributes, arg1_data, arg2_data_length, arg3_key);
+#if defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS)
+    MBEDTLS_TEST_MEMORY_UNPOISON(arg1_data, arg2_data_length);
+#endif /* defined(MBEDTLS_PSA_COPY_CALLER_BUFFERS) */
     return status;
 }