libteec: allow passing settings to session open

Add a new function, TEEC_OpenSession2, that allows a developer to pass
configuration parameters in the form of distinct settings. One of the new
settings is for attaching an arbitrary pointer to the session. This is
useful when an OCALL arrives from the TA and the handler requires
contextual information to proceed that changes depending on which session
the OCALL arrived through.

Having multiple settings in this manner helps reduce the number of
auxiliary functions necessary. Were new functionality to be added in the
future, no new functions would need to be introduced. Instead, one would
only require a new setting.

Signed-off-by: Hernan Gatta <hegatta@microsoft.com>

libteec/src/tee_client_api.c

@@ -669,6 +669,7 @@ TEEC_Result TEEC_OpenSession(TEEC_Context *ctx, TEEC_Session *session,
 	if (res == TEEC_SUCCESS) {
 		session->ctx = ctx;
 		session->session_id = arg->session;
+		session->data_setting.data = NULL;
 	}
 	teec_post_process_operation(operation, params, shm);
 
@@ -680,6 +681,52 @@ TEEC_Result TEEC_OpenSession(TEEC_Context *ctx, TEEC_Session *session,
 	return res;
 }
 
+TEEC_Result TEEC_OpenSession2(TEEC_Context *context,
+			      TEEC_Session *session,
+			      const TEEC_UUID *destination,
+			      uint32_t connectionMethod,
+			      const void *connectionData,
+			      TEEC_Operation *operation,
+			      uint32_t *returnOrigin,
+			      const TEEC_SessionSetting *settings,
+			      uint32_t numSettings)
+{
+	uint32_t n;
+	TEEC_Result res;
+
+	if ((!settings && numSettings) || (settings && !numSettings))
+		return TEEC_ERROR_BAD_PARAMETERS;
+
+	if (settings) {
+		for (n = 0; n < numSettings; n++) {
+			switch (settings[n].type) {
+			case TEEC_SESSION_SETTING_DATA:
+				break;
+			default:
+				return TEEC_ERROR_BAD_PARAMETERS;
+			}
+		}
+	}
+
+	res = TEEC_OpenSession(context, session, destination, connectionMethod,
+			       connectionData, operation, returnOrigin);
+	if (res != TEEC_SUCCESS)
+		return res;
+
+	for (n = 0; n < numSettings; n++) {
+		switch (settings[n].type) {
+		case TEEC_SESSION_SETTING_DATA:
+			session->data_setting.data = settings[n].u.data->data;
+			break;
+		default:
+			/* Not reached */
+			break;
+		}
+	}
+
+	return res;
+}
+
 void TEEC_CloseSession(TEEC_Session *session)
 {
 	struct tee_ioctl_close_session_arg arg;

public/tee_client_api.h

@@ -429,6 +429,38 @@ typedef struct {
 	TEEC_ContextSettingOcall ocall_setting;
 } TEEC_Context;
 
+/**
+ * enum TEEC_SessionSettingType - List of available settings when initializing a
+ * session.
+ */
+typedef enum {
+	TEEC_SESSION_SETTING_DATA = 1
+} TEEC_SessionSettingType;
+
+/**
+ * struct TEEC_SessionSettingData - Setting to attach an arbitrary pointer to a
+ * session; useful when handling OCALLs if per-session data is required by the
+ * OCALL handler.
+ *
+ * @param data  Arbitrary pointer.
+ */
+typedef struct {
+	void *data;
+} TEEC_SessionSettingData;
+
+/**
+ * struct TEEC_SessionSetting - A setting to be used when opening a session.
+ *
+ * @param type  The type of setting this is (i.e., how to interpret the union).
+ * @param u     Union of all possible settings.
+ */
+typedef struct {
+	TEEC_SessionSettingType type;
+	union {
+		const TEEC_SessionSettingData *data;
+	} u;
+} TEEC_SessionSetting;
+
 /**
  * struct TEEC_Session - Represents a connection between a client application
  * and a trusted application.
@@ -437,6 +469,7 @@ typedef struct {
 	/* Implementation defined */
 	TEEC_Context *ctx;
 	uint32_t session_id;
+	TEEC_SessionSettingData data_setting;
 } TEEC_Session;
 
 /**

public/tee_client_api_extensions.h

@@ -72,6 +72,42 @@ TEEC_Result TEEC_InitializeContext2(const char *name, TEEC_Context *ctx,
 				    const TEEC_ContextSetting *settings,
 				    uint32_t numSettings);
 
+/**
+ * TEEC_OpenSession2() - Opens a new session with the specified trusted
+ * application.
+ *
+ * @param context           The initialized TEE context structure in which scope
+ *                          to open the session.
+ * @param session           The session to initialize.
+ * @param destination       A structure identifying the trusted application with
+ *                          which to open a session.
+ * @param connectionMethod  The connection method to use.
+ * @param connectionData    Any data necessary to connect with the chosen
+ *                          connection method. Not supported, should be set to
+ *                          NULL.
+ * @param operation         An operation structure to use in the session. May be
+ *                          set to NULL to signify no operation structure
+ *                          needed.
+ * @param returnOrigin      A parameter which will hold the error origin if this
+ *                          function returns any value other than TEEC_SUCCESS.
+ * @param settings          A list of settings to use to configure the new
+ *                          session, or NULL.
+ * @param numSettings       The number of settings, if any.
+ *
+ * @return TEEC_SUCCESS               Successfully opened a new session.
+ * @return TEEC_ERROR_BAD_PARAMETERS  One or more parameters are wrong.
+ * @return TEEC_Result                Something else failed.
+ */
+TEEC_Result TEEC_OpenSession2(TEEC_Context *context,
+			      TEEC_Session *session,
+			      const TEEC_UUID *destination,
+			      uint32_t connectionMethod,
+			      const void *connectionData,
+			      TEEC_Operation *operation,
+			      uint32_t *returnOrigin,
+			      const TEEC_SessionSetting *settings,
+			      uint32_t numSettings);
+
 #ifdef __cplusplus
 }
 #endif

typedefs.checkpatch

@@ -4,6 +4,9 @@ TEEC_Value
 TEEC_UUID
 TEEC_TempMemoryReference
 TEEC_SharedMemory
+TEEC_SessionSettingType
+TEEC_SessionSettingData
+TEEC_SessionSetting
 TEEC_Session
 TEEC_Result
 TEEC_RegisteredMemoryReference