[PATCH v2 3/6] tee: qcomtee: Allow object invokes from kernel clients

[Harshal Dev <harshal.dev@oss.qualcomm.com>]

From: Amirreza Zarrabi <amirreza.zarrabi@oss.qualcomm.com>

QCOMTEE currently treats UBUF parameters as userspace addresses and
applies userspace restrictions when invoking the root object. This is
not suitable for object invocation requests issued by kernel clients.

Use the kernel_ctx flag to distinguish kernel client requests from
userspace requests. For kernel contexts, do not mark UBUF parameters as
user addresses, and allow permitted root-object operations to proceed
without applying the userspace-only checks.

This allows in-kernel users of tee_client_object_invoke_func() to issue
object invocation requests through the qcomtee backend.

Co-developed-by: Harshal Dev <harshal.dev@oss.qualcomm.com>
Signed-off-by: Harshal Dev <harshal.dev@oss.qualcomm.com>
Signed-off-by: Amirreza Zarrabi <amirreza.zarrabi@oss.qualcomm.com>
---
 drivers/tee/qcomtee/call.c           | 34 +++++++++++++++++++++++-----------
 drivers/tee/qcomtee/qcomtee_object.h |  5 +++--
 include/linux/tee_drv.h              |  5 ++++-
 3 files changed, 30 insertions(+), 14 deletions(-)

diff --git a/drivers/tee/qcomtee/call.c b/drivers/tee/qcomtee/call.c
index 03d33b118f6d..c1bba5fbfa3e 100644
--- a/drivers/tee/qcomtee/call.c
+++ b/drivers/tee/qcomtee/call.c
@@ -202,7 +202,7 @@ int qcomtee_objref_from_arg(struct tee_param *param, struct qcomtee_arg *arg,
  */
 static int qcomtee_params_to_args(struct qcomtee_arg *u,
 				  struct tee_param *params, int num_params,
-				  struct tee_context *ctx)
+				  struct qcomtee_object_invoke_ctx *oic)
 {
 	int i;
 
@@ -210,8 +210,14 @@ static int qcomtee_params_to_args(struct qcomtee_arg *u,
 		switch (params[i].attr) {
 		case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_INPUT:
 		case TEE_IOCTL_PARAM_ATTR_TYPE_UBUF_OUTPUT:
-			u[i].flags = QCOMTEE_ARG_FLAGS_UADDR;
-			u[i].b.uaddr = params[i].u.ubuf.uaddr;
+			u[i].flags = oic->kernel_ctx ? 0 :
+				QCOMTEE_ARG_FLAGS_UADDR;
+
+			if (u[i].flags && QCOMTEE_ARG_FLAGS_UADDR)
+				u[i].b.uaddr = params[i].u.ubuf.uaddr;
+			else
+				u[i].b.addr = params[i].u.ubuf.addr;
+
 			u[i].b.size = params[i].u.ubuf.size;
 
 			if (params[i].attr ==
@@ -223,7 +229,7 @@ static int qcomtee_params_to_args(struct qcomtee_arg *u,
 			break;
 		case TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_INPUT:
 			u[i].type = QCOMTEE_ARG_TYPE_IO;
-			if (qcomtee_objref_to_arg(&u[i], &params[i], ctx))
+			if (qcomtee_objref_to_arg(&u[i], &params[i], oic->ctx))
 				goto out_failed;
 
 			break;
@@ -270,7 +276,7 @@ static int qcomtee_params_to_args(struct qcomtee_arg *u,
  */
 static int qcomtee_params_from_args(struct tee_param *params,
 				    struct qcomtee_arg *u, int num_params,
-				    struct tee_context *ctx)
+				    struct qcomtee_object_invoke_ctx *oic)
 {
 	int i, np;
 
@@ -288,7 +294,8 @@ static int qcomtee_params_from_args(struct tee_param *params,
 			break;
 		case QCOMTEE_ARG_TYPE_OO:
 			/* TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_OUTPUT */
-			if (qcomtee_objref_from_arg(&params[np], &u[np], ctx))
+			if (qcomtee_objref_from_arg(&params[np], &u[np],
+						    oic->ctx))
 				goto out_failed;
 
 			break;
@@ -304,7 +311,7 @@ static int qcomtee_params_from_args(struct tee_param *params,
 	/* Undo qcomtee_objref_from_arg(). */
 	for (i = 0; i < np; i++) {
 		if (params[i].attr == TEE_IOCTL_PARAM_ATTR_TYPE_OBJREF_OUTPUT)
-			qcomtee_context_del_qtee_object(&params[i], ctx);
+			qcomtee_context_del_qtee_object(&params[i], oic->ctx);
 	}
 
 	/* Release any IO and OO objects not processed. */
@@ -357,7 +364,8 @@ static int qcomtee_params_check(struct tee_param *params, int num_params)
 }
 
 /* Check if an operation on ROOT_QCOMTEE_OBJECT from userspace is permitted. */
-static int qcomtee_root_object_check(u32 op, struct tee_param *params,
+static int qcomtee_root_object_check(struct qcomtee_object_invoke_ctx *oic,
+				     u32 op, struct tee_param *params,
 				     int num_params)
 {
 	/* Some privileged operations recognized by QTEE. */
@@ -366,6 +374,9 @@ static int qcomtee_root_object_check(u32 op, struct tee_param *params,
 	    op == QCOMTEE_ROOT_OP_ADCI_SHUTDOWN)
 		return -EINVAL;
 
+	if (oic->kernel_ctx)
+		return 0;
+
 	/*
 	 * QCOMTEE_ROOT_OP_REG_WITH_CREDENTIALS is to register with QTEE
 	 * by passing a credential object as input OBJREF. TEE_OBJREF_NULL as a
@@ -429,7 +440,8 @@ static int qcomtee_object_invoke(struct tee_context *ctx,
 	/* Get an object to invoke. */
 	if (arg->id == TEE_OBJREF_NULL) {
 		/* Use ROOT if TEE_OBJREF_NULL is invoked. */
-		if (qcomtee_root_object_check(arg->op, params, arg->num_params))
+		if (qcomtee_root_object_check(oic, arg->op, params,
+					      arg->num_params))
 			return -EINVAL;
 
 		object = ROOT_QCOMTEE_OBJECT;
@@ -437,7 +449,7 @@ static int qcomtee_object_invoke(struct tee_context *ctx,
 		return -EINVAL;
 	}
 
-	ret = qcomtee_params_to_args(u, params, arg->num_params, ctx);
+	ret = qcomtee_params_to_args(u, params, arg->num_params, oic);
 	if (ret)
 		goto out;
 
@@ -455,7 +467,7 @@ static int qcomtee_object_invoke(struct tee_context *ctx,
 
 	if (!result) {
 		/* Assume service is UNAVAIL if unable to process the result. */
-		if (qcomtee_params_from_args(params, u, arg->num_params, ctx))
+		if (qcomtee_params_from_args(params, u, arg->num_params, oic))
 			result = QCOMTEE_MSG_ERROR_UNAVAIL;
 	} else {
 		/*
diff --git a/drivers/tee/qcomtee/qcomtee_object.h b/drivers/tee/qcomtee/qcomtee_object.h
index 2528d07e4576..7bd6e23b038c 100644
--- a/drivers/tee/qcomtee/qcomtee_object.h
+++ b/drivers/tee/qcomtee/qcomtee_object.h
@@ -112,8 +112,9 @@ struct qcomtee_buffer {
  * @b: address and size if the type of argument is a buffer.
  * @o: object instance if the type of argument is an object.
  *
- * &qcomtee_arg.flags only accepts %QCOMTEE_ARG_FLAGS_UADDR for now, which
- * states that &qcomtee_arg.b contains a userspace address in uaddr.
++ * If %QCOMTEE_ARG_FLAGS_UADDR is set in &qcomtee_arg.flags then it implies
++ * that &qcomtee_arg.b contains a userspace address in uaddr.
++ * Otherwise, &qcomtee_arg.b contains a kernel address in addr.
  */
 struct qcomtee_arg {
 	enum qcomtee_arg_type type;
diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h
index ca99c6b747a8..71d0536db60e 100644
--- a/include/linux/tee_drv.h
+++ b/include/linux/tee_drv.h
@@ -83,7 +83,10 @@ struct tee_param_memref {
 };
 
 struct tee_param_ubuf {
-	void __user *uaddr;
+	union {
+		void *addr;
+		void __user *uaddr;
+	};
 	size_t size;
 };
 

-- 
2.34.1