NAME¶
issetugid
—
is current process tainted by uid or gid
changes
LIBRARY¶
Standard C Library (libc, -lc)
SYNOPSIS¶
#include
<unistd.h>
int
issetugid
(
void);
DESCRIPTION¶
The
issetugid
() 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
execve(2) 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
getenv(3)
should be viewed with suspicion if it is used to control operation.
A “tainted” status is inherited by child processes as a result of
the
fork(2) system call (or other library code
that calls fork, such as
popen(3)).
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
su(1) which begin setuid but
need to be able to create an untainted process.
ERRORS¶
The
issetugid
() system call is always
successful, and no return value is reserved to indicate an error.
SEE ALSO¶
execve(2),
fork(2),
setegid(2),
seteuid(2),
setgid(2),
setregid(2),
setreuid(2),
setuid(2)
HISTORY¶
The
issetugid
() system call first appeared in
OpenBSD 2.0 and was also implemented in
FreeBSD 3.0.