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Revision as of 21:44, 1 February 2011

SingleSignOn Architecture Subsystem Architecture Specification

Contents 1 Document control 1.1 References 1.2 Glossary 1.3 Summary of changes in current version 2 Architecture 2.1 Licensing and IPR view 2.2 Configurability 2.3 Packages 3 Performance 3.1 General Performance Considerations 3.2 Memory 3.3 Runtime 3.4 Power Consumption 4 Security 5 Open items

Document control

References

Tag	Document name	Repository (with hyperlinks)
[ArchGoals]	Architecture Goals	[xxx]
[SystemModel]	Maemo System Model	[xxx]
[PDBv2]	Package database	[xxx]

Glossary

Acronym or term	Description
API	Application Programming Interface
SASL	Simple Authentication and Security Layer

Summary of changes in current version

Update of changed figures and descriptions.

Architecture

Licensing and IPR view

signond component is licensed as GPLv2 due to dependencies. SSO client library is licensed as LGPLv2.1.

Authentication plugins are proprietary, except the built-in plaintext and SASL plugins. SASL plugin is based on open source component.

There are no suitable available open source solutions, which would match the requirements even closely.

Configurability

Locations for database and plugins can be configured during compilation time.

Packages

Package	ver	doc	dev	dbg
libsignon-qt	0	doc	dev	dbg
libsignon-glib	1	doc	dev	dbg
signond	0	doc	dev	dbg
signon-plugins			dev
signon-passwordplugin
signon-saslplugin			dev
signon-doc
signonui-informer-extension
libsignon-ui	0	doc	dev	dbg
signon-ui				dbg
keychain-ui				dbg

Table 3: Packages provided

Performance

General Performance Considerations

• Plugin system provides flexibility to add features
• Data set is limited by user credentials
• Typically users have less than 100 accounts with credentials
• Some operations require remote server responses and time performance is not critical issue
• Long operations are asynchronous by default

Memory

	Explanation	Size [kB]
Flash/OneNAND	Program & library files	2048
Flash/eMMC	Credential database	4096
RAM/Idle	Signond daemon	850
RAM/Peak	Signon-ui	3048

Runtime

• One daemon running
• In typical use case 2-6 DBUS messages are sent
• Token renewal is periodic, depending on service
• Started on demand
• Application start time not affected

Power Consumption

Daemon is in sleep when applications do not need authentication. Power consumption is minimal.

Security

SignOn is huge security risk. It is storing user credentials which should be kept safe. This could also include credit card numbers etc.

- Features that require high (admin / root) permissions or are a part of trusted computing base (kernel, etc.)

- User data or personally identifiable information (PII) is handled

- Network connections are used or relied on

- Externally supplied data is being processed

- Financial transactions are processed or billable events are created

- Cryptographic functionality (algorithms, random number generators, protocols) are used or a 'security feature' is being implemented

• Operational environment of a component or expectations of its operation change

A table below is depicting executables and their credentials.

Credentials required by Single Sign-On subsystem executables

Executable	Credential
signond	UID::root
signond	GID::root
signond	CAP::setuid
signond	CAP::dac_override
signond	CAP::sys_module
signond	CAP::sys_admin
signond	CAP::mknod
signond	CAP::ipc_lock
signond	*::sso-encryption-token
signonpluginprocess	UID::signon
signonpluginprocess	GID::signon

Open items

#	Item	Status	Description
1	Locked device	closed	Should encrypted filesystem be closed when device is locked?
2	DBUS id	closed	How to obtain unique identifier of D-BUS peer. Officially not yet supported by Security Framework.
3	Lock code	closed	Device lock code setting/getting is not defined.
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