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diff --git a/docs/3_Developer_Guides/1_Application_Framework/0_Introduction.md b/docs/3_Developer_Guides/1_Application_Framework/0_Introduction.md deleted file mode 100644 index efc31ee..0000000 --- a/docs/3_Developer_Guides/1_Application_Framework/0_Introduction.md +++ /dev/null @@ -1,261 +0,0 @@ ---- -title: Introduction ---- - -## Foreword - -This document describes what we intend to do. -It may happen that our current implementation and the content of this document differ. - -In case of differences, it is assumed that this document is right and the implementation is wrong. - -## Introduction - -During the first works in having the security model of Tizen integrated in AGL -(Automotive Grade Linux) distribution, it became quickly obvious that the count -of components specific to Tizen to integrate was huge. - -Here is a minimal list of what was needed: - -- platform/appfw/app-installers -- platform/core/security/cert-svc -- platform/core/appfw/ail -- platform/core/appfw/aul-1 -- platform/core/appfw/libslp-db-util -- platform/core/appfw/pkgmgr-info -- platform/core/appfw/slp-pkgmgr - -But this list isn't complete because many dependencies are hidden. -Those hidden dependencies are including some common libraries but also many -tizen specific sub-components: - -- iniparser -- bundle -- dlog, -- libtzplatform-config -- db-util -- vconf-buxton -- ... - -This is an issue because AGL is not expected to be Tizen. -Taking it would either need to patch it for removing unwanted components or to take all of them. - -However, a careful study of the core components of the security framework -of Tizen showed that their dependencies to Tizen are light (and since some -of our work, there is no more dependency to tizen). -Those components are : - -- **cynara** -- **security-manager** -- **D-Bus aware of cynara** - -Luckily, these core security components of Tizen are provided -by [meta-intel-iot-security][meta-intel], a set of yocto layers. -These layers were created by Intel to isolate Tizen specific security -components from the initial port of Tizen to Yocto. -The 3 layers are providing components for: - -- Implementing Smack LSM -- Implementing Integrity Measurement Architecture -- Implementing Tizen Security Framework - -The figure below shows the history of these layers. - - - -We took the decision to use these security layers that provide the -basis of the Tizen security, the security framework. - -For the components of the application framework, built top of -the security framework, instead of pulling the huge set of packages -from Tizen, we decided to refit it by developing a tiny set of -components that would implement the same behaviour but without all -the dependencies and with minor architectural improvements for AGL. - -These components are : - -- **afm-system-daemon** -- **afm-user-daemon** - -They provides infrastructure for installing, uninstalling, -launching, terminating, pausing and resuming applications in -a multi user secure environment. - -A third component exists in the framework, the binder **afb-daemon**. -The binder provides the easiest way to provide secured API for -any tier. -Currently, the use of the binder is not absolutely mandatory. - -This documentation explains the framework created by IoT.bzh -by rewriting the Tizen Application Framework. -Be aware of the previous foreword. - -## Overview - -The figure below shows the major components of the framework -and their interactions going through the following scenario: - -- APPLICATION installs an other application and then launch it. -  - -Let follow the sequence of calls: - -1. APPLICATION calls its **binder** to install the OTHER application. - -1. The binding **afm-main-binding** of the **binder** calls, through - **D-Bus** system, the system daemon to install the OTHER application. - -1. The system **D-Bus** checks wether APPLICATION has the permission - or not to install applications by calling **CYNARA**. - -1. The system **D-Bus** transmits the request to **afm-system-daemon**. - - **afm-system-daemon** checks the application to install, its - signatures and rights and install it. - -1. **afm-system-daemon** calls **SECURITY-MANAGER** for fulfilling - security context of the installed application. - -1. **SECURITY-MANAGER** calls **CYNARA** to install initial permissions - for the application. - -1. APPLICATION call its binder to start the nearly installed OTHER application. - -1. The binding **afm-main-binding** of the **binder** calls, through - **D-Bus** session, the user daemon to launch the OTHER application. - -1. The session **D-Bus** checks wether APPLICATION has the permission - or not to start an application by calling **CYNARA**. - -1. The session **D-Bus** transmits the request to **afm-user-daemon**. - -1. **afm-user-daemon** checks wether APPLICATION has the permission - or not to start the OTHER application **CYNARA**. - -1. **afm-user-daemon** uses **SECURITY-MANAGER** features to set - the security context for the OTHER application. - -1. **afm-user-daemon** launches the OTHER application. - -This scenario does not cover all the features of the frameworks. -Shortly because details will be revealed in the next chapters, -the components are: - -- ***SECURITY-MANAGER***: in charge of setting Smack contexts and rules, - of setting groups, and, of creating initial content of *CYNARA* rules - for applications. - -- ***CYNARA***: in charge of handling API access permissions by users and by - applications. - -- ***D-Bus***: in charge of checking security of messaging. The usual D-Bus - security rules are enhanced by *CYNARA* checking rules. - -- ***afm-system-daemon***: in charge of installing and uninstalling applications. - -- ***afm-user-daemon***: in charge of listing applications, querying application details, - starting, terminating, pausing, resuming applications and their instances - for a given user context. - -- ***afb-binder***: in charge of serving resources and features through an - HTTP interface. - -- ***afm-main-binding***: This binding allows applications to use the API - of the AGL framework. - -## Links between the "Security framework" and the "Application framework" - -The security framework refers to the security model used to ensure -security and to the tools that are provided for implementing that model. - -The security model refers to how DAC (Discretionary Access Control), -MAC (Mandatory Access Control) and Capabilities are used by the system -to ensure security and privacy. -It also includes features of reporting using audit features and by managing -logs and alerts. - -The application framework manages the applications: - -- installing -- uninstalling -- starting -- pausing -- listing -- ... - -The application framework uses the security model/framework -to ensure the security and the privacy of the applications that -it manages. - -The application framework must be compliant with the underlying -security model/framework. -But it should hide it to the applications. - -## The security framework - -The implemented security model is the security model of Tizen 3. -This model is described [here][tizen-secu-3]. - -The security framework then comes from Tizen 3 but through -the [meta-intel]. -It includes: - -- **Security-Manager** -- **Cynara** -- **D-Bus** compliant to Cynara. - -Two patches are applied to the security-manager. -The goal of these patches is to remove specific dependencies with Tizen packages that are not needed by AGL. -None of these patches adds or removes any behaviour. - -**In theory, the security framework/model is an implementation details -that should not impact the layers above the application framework**. - -The security framework of Tizen provides "nice lad" a valuable component to -scan log files and analyse auditing. -This component is still in development. - -## The application framework - -The application framework on top of the security framework -provides the components to install and uninstall applications -and to run it in a secured environment. - -The goal is to manage applications and to hide the details of -the security framework to the applications. - -For the reasons explained in introduction, we did not used the -application framework of Tizen as is but used an adaptation of it. - -The basis is kept identical: - -- The applications are distributed in a digitally signed container that must - match the specifications of widgets (web applications). - -This is described by the technical recommendations [widgets] and -[widgets-digsig] of the W3 consortium. - -This model allows: - -- The distribution of HTML, QML and binary applications. -- The management of signatures of the widget packages. - -This basis is not meant as being rigid and it can be extended in the -future to include for example incremental delivery. - -[meta-intel]: https://github.com/01org/meta-intel-iot-security "A collection of layers providing security technologies" -[widgets]: http://www.w3.org/TR/widgets "Packaged Web Apps" -[widgets-digsig]: http://www.w3.org/TR/widgets-digsig "XML Digital Signatures for Widgets" -[libxml2]: http://xmlsoft.org/html/index.html "libxml2" -[openssl]: https://www.openssl.org "OpenSSL" -[xmlsec]: https://www.aleksey.com/xmlsec "XMLSec" -[json-c]: https://github.com/json-c/json-c "JSON-c" -[d-bus]: http://www.freedesktop.org/wiki/Software/dbus "D-Bus" -[libzip]: http://www.nih.at/libzip "libzip" -[cmake]: https://cmake.org "CMake" -[security-manager]: https://wiki.tizen.org/wiki/Security/Tizen_3.X_Security_Manager "Security-Manager" -[app-manifest]: http://www.w3.org/TR/appmanifest "Web App Manifest" -[tizen-security]: https://wiki.tizen.org/wiki/Security "Tizen security home page" -[tizen-secu-3]: https://wiki.tizen.org/wiki/Security/Tizen_3.X_Overview "Tizen 3 security overview" -[AppFW-APP_install_sequences]: images/AppFW-APP_install_sequences.svg -[Security_model_history]: images/Security_model_history.svg
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