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diff --git a/docs/0-introduction.md b/docs/0-introduction.md index bb89613..e78c091 100644 --- a/docs/0-introduction.md +++ b/docs/0-introduction.md @@ -1,18 +1,14 @@ -AGL framework overview -====================== +# AGL framework overview -Foreword --------- +## Foreword -This document describes what we intend to do. It may happen that our -current implementation and the content of this document differ. +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 ------------- +## Introduction During the first works in having the security model of Tizen integrated in AGL (Automotive Grade Linux) distribution, it became @@ -21,37 +17,47 @@ 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 +- 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. +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, ...). +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. +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**. +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. +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. +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 +- Implementing Smack LSM +- Implementing Integrity Measurement Architecture +- Implementing Tizen Security Framework The figure below shows the history of these layers. @@ -66,26 +72,32 @@ 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** and **afm-user-daemon**. +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**. +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. +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. +by rewriting the Tizen Application Framework. +Be aware of the previous foreword. <!-- pagebreak --> -Overview --------- + +## 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. + +- APPLICATION installs an other application and then launch it. ![AppFW-APP_install_sequences][AppFW-APP_install_sequences]{style width:70%} @@ -93,115 +105,120 @@ Let follow the sequence of calls: 1. APPLICATION calls its **binder** to install the OTHER application. -2. The binding **afm-main-binding** of the **binder** calls, through +1. The binding **afm-main-binding** of the **binder** calls, through **D-Bus** system, the system daemon to install the OTHER application. -3. The system **D-Bus** checks wether APPLICATION has the permission +1. The system **D-Bus** checks wether APPLICATION has the permission or not to install applications by calling **CYNARA**. -4. The system **D-Bus** transmits the request to **afm-system-daemon**. +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. -5. **afm-system-daemon** calls **SECURITY-MANAGER** for fulfilling +1. **afm-system-daemon** calls **SECURITY-MANAGER** for fulfilling security context of the installed application. -6. **SECURITY-MANAGER** calls **CYNARA** to install initial permissions +1. **SECURITY-MANAGER** calls **CYNARA** to install initial permissions for the application. -7. APPLICATION call its binder to start the nearly installed OTHER application. +1. APPLICATION call its binder to start the nearly installed OTHER application. -8. The binding **afm-main-binding** of the **binder** calls, through +1. The binding **afm-main-binding** of the **binder** calls, through **D-Bus** session, the user daemon to launch the OTHER application. -9. The session **D-Bus** checks wether APPLICATION has the permission +1. The session **D-Bus** checks wether APPLICATION has the permission or not to start an application by calling **CYNARA**. -10. The session **D-Bus** transmits the request to **afm-user-daemon**. +1. The session **D-Bus** transmits the request to **afm-user-daemon**. -11. **afm-user-daemon** checks wether APPLICATION has the permission +1. **afm-user-daemon** checks wether APPLICATION has the permission or not to start the OTHER application **CYNARA**. -12. **afm-user-daemon** uses **SECURITY-MANAGER** features to set +1. **afm-user-daemon** uses **SECURITY-MANAGER** features to set the security context for the OTHER application. -13. **afm-user-daemon** launches the OTHER application. +1. **afm-user-daemon** launches the OTHER application. -This scenario does not cover all the features of the frameworks. +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, +- ***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 +- ***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 +- ***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-system-daemon***: in charge of installing and uninstalling applications. -* ***afm-user-daemon***: in charge of listing applications, querying application details, +- ***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 +- ***afb-binder***: in charge of serving resources and features through an HTTP interface. -* ***afm-main-binding***: This binding allows applications to use the API +- ***afm-main-binding***: This binding allows applications to use the API of the AGL framework. - -Links between the "Security framework" and the "Application 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. +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 ... + +- 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. - +security model/framework. +But it should hide it to the applications. -The security framework ----------------------- +## The security framework -The implemented security model is the security model of Tizen 3. +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** -and **D-Bus** compliant to Cynara. +the [meta-intel]. +It includes: -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. +- **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. - +scan log files and analyse auditing. +This component is still in development. -The application framework -------------------------- +## The application framework The application framework on top of the security framework provides the components to install and uninstall applications @@ -213,18 +230,22 @@ 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. +The basis is kept identical: -This model allows the distribution of HTML, QML and binary applications. +- 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. -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" |