is current process tainted by uid or gid
Standard C Library (libc, -lc)
() system call returns 1 if the
process environment or memory address space is considered
“tainted”, and returns 0 otherwise.
A process is tainted if it was created as a result of an
system call which had either of the setuid or setgid bits set (and extra
privileges were given as a result) or if it has changed any of its real,
effective or saved user or group ID's since it began execution.
This system call exists so that library routines (eg: libc, libtermcap) can
reliably determine if it is safe to use information that was obtained from the
user, in particular the results from
should be viewed with suspicion if it is used to control operation.
A “tainted” status is inherited by child processes as a result of
system call (or other library code that calls fork, such as
It is assumed that a program that clears all privileges as it prepares to
execute another will also reset the environment, hence the
“tainted” status will not be passed on. This is important for
programs such as
which begin setuid but need to be able to create an untainted process.
() system call is always
successful, and no return value is reserved to indicate an error.
() system call first appeared in
and was also implemented in