I think this would be a "temporary root", rather than something like CF-AutoRoot that gains persistence by modifying the system itself.

The ironic part is that since DirtyCOW is a kernel bug they could probably modify the exploit to disable SELinux from inside the kernel (or load a module that disables SELinux). But they're just trying to use the PoC as the only thing you can get from the exploit.

I suspect you got much the same back in the microcomputer era. Just look at the various phreaker stuff salvaged from BBSs.

What's the difference between "I can become the root user on my phone whenever I want" and "My phone is rooted"?

Note: I'm asking as a GNU/Linux user, not as a phone user.

Thanks!

edit: Apparently SETUID is disabled on Android:

  ... using kernel features that help block privilege escalation (e.g. NOSUID, NO_NEW_PRIVS).

also: https://unix.stackexchange.com/a/250806/95938

What are these different "methods" listed in the table here?

https://github.com/dirtycow/dirtycow.github.io/wiki/PoCs

Can one of those methods allow me to write to some file in /etc? (Which is enough to grant me the access I want, unless selinux is just MAGIC.)

You would need to be able to `setenforce 0 `. A properly configured SELinux context can prevent you from doing that however we are starting to finally see some reports of dirtyc0w successfuly leading to `SELinux status: permissive` and permanent root.

Maybe pseudo-sudo?