Android Security Internals

Chapter 12. Selinux

While previous chapters mentioned Security-Enhanced Linux (SELinux) and its Android integration, our discussion of Android’s security model up until now has focused on Android’s “traditional” sandbox implementation, which relies heavily on Linux’s default discretionary access control (DAC). The Linux DAC is lightweight and well understood, but it has certain disadvantages, most notably the coarse granularity of DAC permissions, the potential for misconfigured programs to leak data, and the inability to apply fine-grained privilege constraints to processes that run as the root user. (While POSIX capabilities, which are implemented as an extension to the traditional DAC in Linux, offer a way to grant only certain privileges to ...