Short initializers for multipart operation structures

For each multipart or interruptible operation, define an initializer
function that simulates the minimum that `my_op_t op = {0}` guarantees in C.
That is, initialize most fields to 0, but set the fields that are unions to
a nonzero value. This simulates platforms where initializing a union to
`{0}` only initializes the first member, and thus reading from another
member can yield a nonzero value. In our operation structures, the union's
first member is an unused `dummy`, and the other members are
driver-specific, so we just make the whole union nonzero and this has to be
good enough for the setup functions in the core to cope.

Signed-off-by: Gilles Peskine <[email protected]>

tests/include/test/psa_crypto_helpers.h

@@ -145,6 +145,35 @@ const char *mbedtls_test_helper_is_psa_leaking(void);
     while (0)
 
 
+/** Initializer that doesn't set the embedded union to zero.
+ *
+ * Use this to validate that our code correctly handles platforms where
+ * `{0}` does not initialize a union to all-bits-zero, only the first member.
+ * Such behavior is uncommon, but compliant (see discussion in
+ * https://github.com/Mbed-TLS/mbedtls/issues/9814).
+ * You can portably simulate that behavior by using the `xxx_init_short()`
+ * initializer function instead of `{0}` or an official initializer
+ * `xxx_init()` or `XXX_INIT`.
+ */
+psa_hash_operation_t psa_hash_operation_init_short(void);
+psa_mac_operation_t psa_mac_operation_init_short(void);
+psa_cipher_operation_t psa_cipher_operation_init_short(void);
+psa_aead_operation_t psa_aead_operation_init_short(void);
+psa_key_derivation_operation_t psa_key_derivation_operation_init_short(void);
+psa_pake_operation_t psa_pake_operation_init_short(void);
+psa_sign_hash_interruptible_operation_t psa_sign_hash_interruptible_operation_init_short(void);
+psa_verify_hash_interruptible_operation_t psa_verify_hash_interruptible_operation_init_short(void);
+#if defined(PSA_KEY_AGREEMENT_IOP_INIT)
+psa_key_agreement_iop_t psa_key_agreement_iop_init_short(void);
+#endif
+#if defined(PSA_GENERATE_KEY_IOP_INIT)
+psa_generate_key_iop_t psa_generate_key_iop_init_short(void);
+#endif
+#if defined(PSA_EXPORT_PUBLIC_KEY_IOP_INIT)
+psa_export_public_key_iop_t psa_export_public_key_iop_init_short(void);
+#endif
+
+
 
 #if defined(RECORD_PSA_STATUS_COVERAGE_LOG)
 psa_status_t mbedtls_test_record_status(psa_status_t status,

tests/src/psa_crypto_helpers.c

@@ -98,6 +98,94 @@ const char *mbedtls_test_helper_is_psa_leaking(void)
     return NULL;
 }
 
+
+
+psa_hash_operation_t psa_hash_operation_init_short(void)
+{
+    psa_hash_operation_t operation = {0};
+    memset(&operation.ctx, '!', sizeof(operation.ctx));
+    return operation;
+}
+
+psa_mac_operation_t psa_mac_operation_init_short(void)
+{
+    psa_mac_operation_t operation = {0};
+    memset(&operation.ctx, '!', sizeof(operation.ctx));
+    return operation;
+}
+
+psa_cipher_operation_t psa_cipher_operation_init_short(void)
+{
+    psa_cipher_operation_t operation = {0};
+    memset(&operation.ctx, '!', sizeof(operation.ctx));
+    return operation;
+}
+
+psa_aead_operation_t psa_aead_operation_init_short(void)
+{
+    psa_aead_operation_t operation = {0};
+    memset(&operation.ctx, '!', sizeof(operation.ctx));
+    return operation;
+}
+
+psa_key_derivation_operation_t psa_key_derivation_operation_init_short(void)
+{
+    psa_key_derivation_operation_t operation = {0};
+    memset(&operation.ctx, '!', sizeof(operation.ctx));
+    return operation;
+}
+
+psa_pake_operation_t psa_pake_operation_init_short(void)
+{
+    psa_pake_operation_t operation = {0};
+    memset(&operation.computation_stage, '!', sizeof(operation.computation_stage));
+    memset(&operation.data, '!', sizeof(operation.data));
+    return operation;
+}
+
+psa_sign_hash_interruptible_operation_t psa_sign_hash_interruptible_operation_init_short(void)
+{
+    psa_sign_hash_interruptible_operation_t operation = {0};
+    memset(&operation.ctx, '!', sizeof(operation.ctx));
+    return operation;
+}
+
+psa_verify_hash_interruptible_operation_t psa_verify_hash_interruptible_operation_init_short(void)
+{
+    psa_verify_hash_interruptible_operation_t operation = {0};
+    memset(&operation.ctx, '!', sizeof(operation.ctx));
+    return operation;
+}
+
+#if defined(PSA_KEY_AGREEMENT_IOP_INIT)
+psa_key_agreement_iop_t psa_key_agreement_iop_init_short(void)
+{
+    psa_key_agreement_iop_t operation = {0};
+    memset(&operation.ctx, '!', sizeof(operation.ctx));
+    return operation;
+}
+#endif
+
+#if defined(PSA_GENERATE_KEY_IOP_INIT)
+psa_generate_key_iop_t psa_generate_key_iop_init_short(void)
+{
+    psa_generate_key_iop_t operation = {0};
+    memset(&operation.ctx, '!', sizeof(operation.ctx));
+    return operation;
+}
+#endif
+
+#if defined(PSA_EXPORT_PUBLIC_KEY_IOP_INIT)
+psa_export_public_key_iop_t psa_export_public_key_iop_init_short(void)
+{
+    psa_export_public_key_iop_t operation = {0};
+    memset(&operation.ctx, '!', sizeof(operation.ctx));
+    return operation;
+}
+#endif
+
+
+
 #if defined(RECORD_PSA_STATUS_COVERAGE_LOG)
 /** Name of the file where return statuses are logged by #RECORD_STATUS. */
 #define STATUS_LOG_FILE_NAME "statuses.log"