Patent Application
20080072276
Execution of applications may be carried out using a VM 18 (e.g., Common Language Runtime, ECMA runtime, etc.). A security manager 20 allows the VM 18, at runtime, to configure the rights to one or more permissions (e.g., User Interface, Web Access, Printing, etc.) allowed to an application based on application characteristics (e.g., code group). The VM 18 and security managers 20 are generally known in the art. A novel aspect of the system includes the use of concurrent multiple assembly caches (24-28) by a single application. A Resource Installer 22 may be used to install resources (e.g., assembly files) into one or more assembly caches 24-28.
An application may include one or more assemblies needed for the application to run properly. One or more applications may share their assemblies with other applications running on the computer. Assemblies and/or application resources may be installed into assembly caches 24-28 to facilitate this sharing between applications while conserving their own security policies. Like the one or more applications they are used for, assemblies may come from various sources including, but not limited to, internet, intranet, local computer, remote server, and/or readable media. The assembly caches may be used to separately store assemblies into respective caches based on the source from which the assembly came, along with other factors that may be determined by a security policy. For example, an Internet assembly cache may be created with security policy and permissions relating to assemblies from the Internet.
A security policy may consist of a series of permissions and rights from various policy levels. An assembly's granted and refused permission sets are resolved, at runtime, by the security manager 20 using the permissions found in all (or some) policy levels including enterprise, machine, user and application domain policy levels. Policy levels are applied based on the membership of the assembly with defined identity, publisher, source (e.g., URL, website), origin (e.g., Internet, Intranet) and/or other information. Each policy level that an assembly belongs to may define permissions. The combination of permissions may be referred to as a permission set. Rights may also be assigned according to policy level and/or other assembly information.
An assembly cache may be associated with any security policy. In fact, each assembly caches may be associated with a different security policy. The security policy may be a combination of permissions from one or more of an enterprise, machine, user or application domain policy level. Policies and permissions on the enterprise level may apply to all (or some) computers of the network. Unique machines on the network may require a machine policy and permissions that are not addressed under enterprise policy. A user policy and permissions may apply to an individual user that logs in to the computer. Application level policy and permissions may be defined by the application developer to ensure optimal functionalities of the application. The combination of enterprise, machine, user, application, and/or other policies determine the set of permissions a security policy may enforce for an assembly cache. A security policy may be predetermined and characterized by name.
The permissions assigned to an application at runtime may be compared to the permission set of an assembly cache. Rights may be further enforced upon access. Thus, one or more applications operating according to the same or similar permissions set (security policy) may share resources from a commonly shared assembly cache without having to create private resource directories for each application. Additionally, the application(s) may be restricted from accessing secure shared resources for which they do not have the appropriate permissions and permissions rights.
One or more applications may access one or more of the assembly caches during runtime. By way of example, application code originating from the Internet (e.g., unsecured source) may have limited permissions with respect to actions that may be performed. An application can potentially access assemblies from any cache based on the security manager's (20) restriction which, intersect the application permission set with the one from the assembly cache, and any other restriction of assembly itself could have. This prevents the application from being granted elevated rights. In another example, an application at runtime may be fully trusted and have unrestricted rights on permissions to perform any number of actions. An attempt by the fully trusted application to access an assembly cache with less trusted resources may, at first glance, seem unproductive since the fully trusted application would not be able to perform all the actions necessary for proper function of the application. The security policy of the assembly cache would not allow all the requested permissions to execute. However, this functions to contain un-trusted, or semi-trusted, code because it makes sure that the application will not supply permissions higher than what the assembly cache provides.
Each assembly cache may further have configurable rules for assembly resolution (e.g. cache priority), assembly retention (e.g., Internet cache), and assembly creation (e.g. transparent cache, cache using digital signatures). The rules may aid in keeping assembly caches up to date with current application running on a system and for maximizing use of shared memory.
In order to reduce the performance impact of delays introduced with multiple assembly caches, some instances of the multiple assembly caches may be implemented using a flat naming structure. Shared assemblies stored in the assembly cache may be called from other code named using name, version, culture, and public key token, among other things, in one long string rather than in complicated hierarchical directories of the prior art. Thus, for some multiple assembly caches the assemblies are simple, faster to browse, and easier to cache.
In the foregoing specification, the invention has been described with reference to specific embodiments thereof. Various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.
