Re: [RFC 1/1] LSM ptags: Add tagging of processes

[Tetsuo Handa]

Jose Bollo wrote:
> The fact is that ptags is seat behind the implementation of the special
> files in /proc/PID/attr/.. Thus, it has to return an allocated buffer.
> I'm not aware of what kind of allocation is possible to use for this
> subsystem. Is it possible to use vmalloc? I dont know.

If you replace kfree() with kvfree() in proc_pid_attr_read() in fs/proc/base.c ,
you will be able to use vmalloc(). However, proc_pid_attr_write() accepts only
PAGE_SIZE bytes from the beginning. If you want to use attributes longer than
PAGE_SIZE bytes, I think that you will need to use a different interface because
implementing I/O protocol for ptags which reads/writes PAGE_SIZE bytes chunk
at a time using /proc/PID/attr/ interface is not userspace friendly.