tee: add TEE_IOCTL_PARAM_ATTR_META

Adds TEE_IOCTL_PARAM_ATTR_META which can be used to indicate meta
parameters when communicating with user space. These meta parameters can
be used by supplicant support multiple parallel requests at a time.

Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

drivers/tee/optee/supp.c

@@ -119,6 +119,27 @@ u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params,
 	return ret;
 }
 
+static int supp_check_recv_params(size_t num_params, struct tee_param *params)
+{
+	size_t n;
+
+	/*
+	 * If there's memrefs we need to decrease those as they where
+	 * increased earlier and we'll even refuse to accept any below.
+	 */
+	for (n = 0; n < num_params; n++)
+		if (tee_param_is_memref(params + n) && params[n].u.memref.shm)
+			tee_shm_put(params[n].u.memref.shm);
+
+	/*
+	 * We only expect parameters as TEE_IOCTL_PARAM_ATTR_TYPE_NONE (0).
+	 */
+	for (n = 0; n < num_params; n++)
+		if (params[n].attr)
+			return -EINVAL;
+	return 0;
+}
+
 /**
  * optee_supp_recv() - receive request for supplicant
  * @ctx:	context receiving the request
@@ -137,6 +158,10 @@ int optee_supp_recv(struct tee_context *ctx, u32 *func, u32 *num_params,
 	struct optee_supp *supp = &optee->supp;
 	int rc;
 
+	rc = supp_check_recv_params(*num_params, param);
+	if (rc)
+		return rc;
+
 	/*
 	 * In case two threads in one supplicant is calling this function
 	 * simultaneously we need to protect the data with a mutex which

drivers/tee/tee_core.c

@@ -152,11 +152,11 @@ static int params_from_user(struct tee_context *ctx, struct tee_param *params,
 			return -EFAULT;
 
 		/* All unused attribute bits has to be zero */
-		if (ip.attr & ~TEE_IOCTL_PARAM_ATTR_TYPE_MASK)
+		if (ip.attr & ~TEE_IOCTL_PARAM_ATTR_MASK)
 			return -EINVAL;
 
 		params[n].attr = ip.attr;
-		switch (ip.attr) {
+		switch (ip.attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK) {
 		case TEE_IOCTL_PARAM_ATTR_TYPE_NONE:
 		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
 			break;
@@ -394,8 +394,8 @@ static int params_to_supp(struct tee_context *ctx,
 		struct tee_ioctl_param ip;
 		struct tee_param *p = params + n;
 
-		ip.attr = p->attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK;
-		switch (p->attr) {
+		ip.attr = p->attr;
+		switch (p->attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK) {
 		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INPUT:
 		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
 			ip.a = p->u.value.a;
@@ -459,6 +459,10 @@ static int tee_ioctl_supp_recv(struct tee_context *ctx,
 	if (!params)
 		return -ENOMEM;
 
+	rc = params_from_user(ctx, params, num_params, uarg->params);
+	if (rc)
+		goto out;
+
 	rc = ctx->teedev->desc->ops->supp_recv(ctx, &func, &num_params, params);
 	if (rc)
 		goto out;
@@ -488,11 +492,11 @@ static int params_from_supp(struct tee_param *params, size_t num_params,
 			return -EFAULT;
 
 		/* All unused attribute bits has to be zero */
-		if (ip.attr & ~TEE_IOCTL_PARAM_ATTR_TYPE_MASK)
+		if (ip.attr & ~TEE_IOCTL_PARAM_ATTR_MASK)
 			return -EINVAL;
 
 		p->attr = ip.attr;
-		switch (ip.attr) {
+		switch (ip.attr & TEE_IOCTL_PARAM_ATTR_TYPE_MASK) {
 		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_OUTPUT:
 		case TEE_IOCTL_PARAM_ATTR_TYPE_VALUE_INOUT:
 			/* Only out and in/out values can be updated */

include/uapi/linux/tee.h

@@ -154,6 +154,13 @@ struct tee_ioctl_buf_data {
  */
 #define TEE_IOCTL_PARAM_ATTR_TYPE_MASK		0xff
 
+/* Meta parameter carrying extra information about the message. */
+#define TEE_IOCTL_PARAM_ATTR_META		0x100
+
+/* Mask of all known attr bits */
+#define TEE_IOCTL_PARAM_ATTR_MASK \
+	(TEE_IOCTL_PARAM_ATTR_TYPE_MASK | TEE_IOCTL_PARAM_ATTR_META)
+
 /*
  * Matches TEEC_LOGIN_* in GP TEE Client API
  * Are only defined for GP compliant TEEs