- #FAST CHROMIUM BASED BROWSER SOFTWARE#
- #FAST CHROMIUM BASED BROWSER CODE#
- #FAST CHROMIUM BASED BROWSER DOWNLOAD#
Blocking APIs always validate that they run in a context that allows blocking.
It would be a shame if the entire UI would freeze while the browser tries to write a file, or a single tab waits for server response.Īny blocking task that runs in the browser must be marked as such, and it would usually run in a dedicated thread. In order to maintain a fluid user experience, the browser doesn’t allow blocking/synchronous operations to run everywhere. Mojo's top level design, taken from the official documentation Blocking/Non blocking threads it doesn’t allow passing file path objects if the receiver might not have permissions to it now or later on). It also allows validations that the browser uses for security (e.g. Mojo is relatively similar to other IPC systems, but is unique for its ability to pass object handles - such as file descriptors and file handles. That way, when we upload a file, the renderer process asks the browser for the file’s contents - and the renderer doesn’t need to actually access the filesystem. Nowadays, the different components of Chromium communicate with each other almost only using Mojo.
#FAST CHROMIUM BASED BROWSER CODE#
Mojo is the successor of a legacy IPC system, which barely exists as most code was migrated. To make it simple, it allows components (within the same process or not) to communicate with each other over predefined messages, in different languages. Mojo is a platform-agnostic collection of runtime libraries, providing inter process communication primitives, a messaging format and a binding system.
#FAST CHROMIUM BASED BROWSER DOWNLOAD#
But how do they work together? If tabs are sandboxed and cannot access most of the operating system’s features, how can we listen to music or download files? It all starts with a bit of mojo. So we’ve got different logics in different processes, and some of them are tightly restricted. It has a browser process, some utility processes, a tab process for each tab and an extension process. In this example, we can see a browser with 2 tabs. You can view your own browser’s processes by opening the browser’s task manager:
Extension Processes - each extension runs in its own process. The network service is an example of such process, and it's responsible for, as you can guess, network operations Utility/Service processes - Provide specific capabilities as a service. In Chromium, a different renderer instance is created per frame (tab, iframe, etc), usually in its own process Frame/Tab processes - The renderer of the tab itself. It is not sandboxed, provides capabilities via its interfaces and acts as a broker between different processes The browser process - The main broker of the engine. So what kind of processes do we have? Here are some notable examples To be as fast as it can, it uses more operating system resources. As more “services” or logical components are moved out of the browser process, it is more likely to recover from errors and crashes - it might be possible to just relaunch the service seamlessly. This separation is also good for the user’s experience. This makes exploiting the browser much harder, as in most cases you will have to chain multiple vulnerabilities in order to gain control of the whole browser Also, different types of processes have different privileges. Different sites will run in different renderers who have different processes. In Chromium, a renderer doesn’t run in the main browser’s process. It’s harder to isolate threads, so the browser leverages operating system’s features and isolates processes. If we run all of our code in the same process, exploiting one part can lead to code execution all over the browser. But why are they all needed?įirst of all, for security reasons. One of the most commonly known facts about Chromium based browsers is that they have lots of processes. There are other types of plugins supported, we will cover some of them later on. In Chromium, extensions run in their own process. They allow adding capabilities to the web platform by third parties. Built mostly with web technologies such as HTML, CSS, JavaScript, etc. #FAST CHROMIUM BASED BROWSER SOFTWARE#
Extensions - Software plugins for the web browser. Implemented differently per operating system. Usually implemented by restricting process privileges via operating system features. Sandboxing - The concept of isolating and limiting a component. 
Used for communication between the different processes and components of the browser.
Mojo - Chromium’s IPC (Inter Process Communication) system. Some APIs are exposed globally across the browser, some are limited to specific components (e.g. Chrome API - JS events and functions that the browser exposes. V8 - The JavaScript engine used in Chromium. Renderer - Usually refers to a process running the rendering engine. It was forked from Apple’s WebKit in 2013. Blink - The rendering engine used in Chromium. It takes the tags and implements their behavior. Rendering Engine - The component responsible to parse and transform HTML to what we see as web pages.
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