Now that we are aware that file contexts are stored as extended attributes, how do we ensure that files receive the correct label when they are written or modified? For that, a number of guidelines exist, ranging from inheritance rules to explicit commands, to set a SELinux context on a file system resource.
By default, the SELinux security subsystem uses context inheritance to identify which context should be assigned to a file (or directory, socket, and so on) when it is created. A file created in a directory with a var_t context will be assigned the var_t context as well. This means that inheritance is based on the parent directory and not on the context of the executing process.
There are a few exceptions to this though:
In the case of SELinux-aware applications, the application can force the context of a file to be different (assuming the SELinux policy allows it, of course). As this is completely within the realm of the software...