setfsgid
Hurricane Electric Internet Services
NAME
setfsgid - set group identity used for file system checks
SYNOPSIS
int setfsgid(uid_t fsgid)
DESCRIPTION
setfsgid sets the group ID that the Linux kernel uses to
check for all accesses to the file system. Normally, the
value of fsgid will shadow the value of the effective
group ID. In fact, whenever the effective group ID is
changed, fsgid will also be changed to new value of effec-
tive group ID.
An explict call to setfsgid is usually only used by pro-
grams such as the Linux NFS server that need to change
what group ID is used for file access without a corre-
sponding change in the real and effective group IDs. A
change in the normal group IDs for a program such as the
NFS server is a security hole that can expose it to
unwanted signals from other group IDs.
setfsgid will only succeed if the caller is the superuser
or if fsgid matches either the real group ID, effective
group ID, saved group ID, or the current value of fsgid.
RETURN VALUE
On success, the previous value of fsgid is returned. On
error, the current value of fsgid is returned.
CONFORMING TO
setfsgid is Linux specific.
BUGS
No error messages of any kind are returned to the caller.
At the very least, EPERM should be returned when the call
fails.
SEE ALSO
setfsuid(2)
Hurricane Electric Internet Services
Copyright (C) 1998
Hurricane Electric.
All Rights Reserved.