Information flow analysis

Another analytical investigation of SELinux policy is information flow analysis. Unlike domain transitions, which look at how one domain can gain a certain set of permissions through transitions toward other domains, information flow analysis looks at how a domain could leak (purposefully or not) information toward another domain.

Information flow analysis is performed by looking at all operations that occur between two types. A source type can be read by a domain, which subsequently can write information to another type. This simple approach is a two-step flow analysis.

However, it is not as simple as just checking read and write operations (although that is of course perfectly possible). Information can be leaked through file names, file descriptors, and more. Information flow analysis must take all these approaches into account.

Using apol for information flow analysis

After loading a SELinux policy, select Information Flow Analysis as the analysis method. The following...