Why the PF_SUPERPRIV flag is cleared?

rohan puri rohan.puri15 at gmail.com
Thu Sep 8 06:09:30 EDT 2011


    When forking a child process, the copy_process() function will by
default clear the PF_SUPERPRIV flag, which indicates whether a process
use superuser privileges. That means a  superuser process will create
a child process does not has superuser privileges. I think the child
process of a superuser process should also be a superuser one, while
the child process of a normal process by default should also be a
normal one (except that the setuid bit of the child executable is turn
on). In both cases it is not necessary that the PF_SUPERPRIV flag to
be cleared.  So, I wonder why the PF_SUPERPRIV flag is cleared by


This flag PF_SUPERPRI, indicates used superuser privileges and not use
superuser privileges. Which in any case, INDEPENDENT of all the processes
which have superuser privileges, whether they had used them or not and for
those processes which do not have superuser privileges needs to be cleared
for the child of them (since the child process has been just created and at
this point in time it has not used the superuser privileges) Its a kind of
initialization you can think of.

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