optee: add error checks in optee_ffa_do_call_with_arg()

Adds error checking in optee_ffa_do_call_with_arg() for correctness.

Fixes: 4615e5a ("optee: add FF-A support")
Reviewed-by: Sumit Garg <[email protected]>
Signed-off-by: Jens Wiklander <[email protected]>

Author: jenswi-linaro

drivers/tee/optee/ffa_abi.c

@@ -619,9 +619,18 @@ static int optee_ffa_do_call_with_arg(struct tee_context *ctx,
 		.data2 = (u32)(shm->sec_world_id >> 32),
 		.data3 = shm->offset,
 	};
-	struct optee_msg_arg *arg = tee_shm_get_va(shm, 0);
-	unsigned int rpc_arg_offs = OPTEE_MSG_GET_ARG_SIZE(arg->num_params);
-	struct optee_msg_arg *rpc_arg = tee_shm_get_va(shm, rpc_arg_offs);
+	struct optee_msg_arg *arg;
+	unsigned int rpc_arg_offs;
+	struct optee_msg_arg *rpc_arg;
+
+	arg = tee_shm_get_va(shm, 0);
+	if (IS_ERR(arg))
+		return PTR_ERR(arg);
+
+	rpc_arg_offs = OPTEE_MSG_GET_ARG_SIZE(arg->num_params);
+	rpc_arg = tee_shm_get_va(shm, rpc_arg_offs);
+	if (IS_ERR(rpc_arg))
+		return PTR_ERR(rpc_arg);
 
 	return optee_ffa_yielding_call(ctx, &data, rpc_arg);
 }