tee: refactor params_from_user()

Break out the memref handling into a separate helper function.
No change in behavior.

Reviewed-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

Author: jenswi-linaro

drivers/tee/tee_core.c

@@ -354,15 +354,64 @@ tee_ioctl_shm_register(struct tee_context *ctx,
 	return ret;
 }
 
+static int param_from_user_memref(struct tee_context *ctx,
+				  struct tee_param_memref *memref,
+				  struct tee_ioctl_param *ip)
+{
+	struct tee_shm *shm;
+
+	/*
+	 * If a NULL pointer is passed to a TA in the TEE,
+	 * the ip.c IOCTL parameters is set to TEE_MEMREF_NULL
+	 * indicating a NULL memory reference.
+	 */
+	if (ip->c != TEE_MEMREF_NULL) {
+		/*
+		 * If we fail to get a pointer to a shared
+		 * memory object (and increase the ref count)
+		 * from an identifier we return an error. All
+		 * pointers that has been added in params have
+		 * an increased ref count. It's the callers
+		 * responibility to do tee_shm_put() on all
+		 * resolved pointers.
+		 */
+		shm = tee_shm_get_from_id(ctx, ip->c);
+		if (IS_ERR(shm))
+			return PTR_ERR(shm);
+
+		/*
+		 * Ensure offset + size does not overflow
+		 * offset and does not overflow the size of
+		 * the referred shared memory object.
+		 */
+		if ((ip->a + ip->b) < ip->a ||
+		    (ip->a + ip->b) > shm->size) {
+			tee_shm_put(shm);
+			return -EINVAL;
+		}
+	} else if (ctx->cap_memref_null) {
+		/* Pass NULL pointer to OP-TEE */
+		shm = NULL;
+	} else {
+		return -EINVAL;
+	}
+
+	memref->shm_offs = ip->a;
+	memref->size = ip->b;
+	memref->shm = shm;
+
+	return 0;
+}
+
 static int params_from_user(struct tee_context *ctx, struct tee_param *params,
 			    size_t num_params,
 			    struct tee_ioctl_param __user *uparams)
 {
 	size_t n;
 
 	for (n = 0; n < num_params; n++) {
-		struct tee_shm *shm;
 		struct tee_ioctl_param ip;
+		int rc;
 
 		if (copy_from_user(&ip, uparams + n, sizeof(ip)))
 			return -EFAULT;
@@ -385,45 +434,10 @@ static int params_from_user(struct tee_context *ctx, struct tee_param *params,
 		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INPUT:
 		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_OUTPUT:
 		case TEE_IOCTL_PARAM_ATTR_TYPE_MEMREF_INOUT:
-			/*
-			 * If a NULL pointer is passed to a TA in the TEE,
-			 * the ip.c IOCTL parameters is set to TEE_MEMREF_NULL
-			 * indicating a NULL memory reference.
-			 */
-			if (ip.c != TEE_MEMREF_NULL) {
-				/*
-				 * If we fail to get a pointer to a shared
-				 * memory object (and increase the ref count)
-				 * from an identifier we return an error. All
-				 * pointers that has been added in params have
-				 * an increased ref count. It's the callers
-				 * responibility to do tee_shm_put() on all
-				 * resolved pointers.
-				 */
-				shm = tee_shm_get_from_id(ctx, ip.c);
-				if (IS_ERR(shm))
-					return PTR_ERR(shm);
-
-				/*
-				 * Ensure offset + size does not overflow
-				 * offset and does not overflow the size of
-				 * the referred shared memory object.
-				 */
-				if ((ip.a + ip.b) < ip.a ||
-				    (ip.a + ip.b) > shm->size) {
-					tee_shm_put(shm);
-					return -EINVAL;
-				}
-			} else if (ctx->cap_memref_null) {
-				/* Pass NULL pointer to OP-TEE */
-				shm = NULL;
-			} else {
-				return -EINVAL;
-			}
-
-			params[n].u.memref.shm_offs = ip.a;
-			params[n].u.memref.size = ip.b;
-			params[n].u.memref.shm = shm;
+			rc = param_from_user_memref(ctx, &params[n].u.memref,
+						    &ip);
+			if (rc)
+				return rc;
 			break;
 		default:
 			/* Unknown attribute */