Ubuntu Manpage: setpriv - run a program with different Linux privilege settings

Provided by: util-linux_2.34-0.1ubuntu9.6_amd64

NAME

       setpriv - run a program with different Linux privilege settings

SYNOPSIS

       setpriv [options] program [arguments]

DESCRIPTION

       Sets or queries various Linux privilege settings that are inherited across execve(2).

       In comparison to su(1) and runuser(1), setpriv(1) neither uses PAM, nor does it prompt for
       a password.  It is a simple, non-set-user-ID wrapper around execve(2), and can be used  to
       drop  privileges in the same way as setuidgid(8) from daemontools, chpst(8) from runit, or
       similar tools shipped by other service managers.

OPTION

--clear-groups
Clear supplementary groups.

-d, --dump
Dump current privilege state. Can be specified more than once to show extra,
mostly useless, information. Incompatible with all other options.

--groups group...
Set supplementary groups. The argument is a comma-separated list of GIDs or names.

--inh-caps (+|-)cap... or --ambient-caps (+|-)cap... or --bounding-set (+|-)cap...
Set the inheritable capabilities, ambient capabilities or the capability bounding
set. See capabilities(7). The argument is a comma-separated list of +cap and -cap
entries, which add or remove an entry respectively. cap can either be a human-
readable name as seen in capabilities(7) without the cap_ prefix or of the format
cap_N, where N is the internal capability index used by Linux. +all and -all can
be used to add or remove all caps. The set of capabilities starts out as the
current inheritable set for --inh-caps, the current ambient set for --ambient-caps
and the current bounding set for --bounding-set. If you drop something from the
bounding set without also dropping it from the inheritable set, you are likely to
become confused. Do not do that.

--keep-groups
Preserve supplementary groups. Only useful in conjunction with --rgid, --egid, or
--regid.

--init-groups
Initialize supplementary groups using initgroups(3). Only useful in conjunction
with --ruid or --reuid.

--list-caps
List all known capabilities. This option must be specified alone.

--no-new-privs
Set the no_new_privs bit. With this bit set, execve(2) will not grant new
privileges. For example, the set-user-ID and set-group-ID bits as well as file
capabilities will be disabled. (Executing binaries with these bits set will still
work, but they will not gain privileges. Certain LSMs, especially AppArmor, may
result in failures to execute certain programs.) This bit is inherited by child
processes and cannot be unset. See prctl(2) and Documentation/prctl/no_new_
privs.txt in the Linux kernel source.

The no_new_privs bit is supported since Linux 3.5.

--rgid gid, --egid gid, --regid gid
Set the real, effective, or both GIDs. The gid argument can be given as textual
group name.

For safety, you must specify one of --clear-groups, --groups, --keep-groups, or
--init-groups if you set any primary gid.

--ruid uid, --euid uid, --reuid uid
Set the real, effective, or both UIDs. The uid argument can be given as textual
login name.

Setting a uid or gid does not change capabilities, although the exec call at the
end might change capabilities. This means that, if you are root, you probably want
to do something like:

setpriv --reuid=1000 --regid=1000 --inh-caps=-all

--securebits (+|-)securebit...
Set or clear securebits. The argument is a comma-separated list. The valid
securebits are noroot, noroot_locked, no_setuid_fixup, no_setuid_fixup_locked, and
keep_caps_locked. keep_caps is cleared by execve(2) and is therefore not allowed.

--pdeathsig keep|clear|<signal>
Keep, clear or set the parent death signal. Some LSMs, most notably SELinux and
AppArmor, clear the signal when the process' credentials change. Using --pdeathsig
keep will restore the parent death signal after changing credentials to remedy that
situation.

--selinux-label label
Request a particular SELinux transition (using a transition on exec, not dyntrans).
This will fail and cause setpriv(1) to abort if SELinux is not in use, and the
transition may be ignored or cause execve(2) to fail at SELinux's whim. (In
particular, this is unlikely to work in conjunction with no_new_privs.) This is
similar to runcon(1).

--apparmor-profile profile
Request a particular AppArmor profile (using a transition on exec). This will fail
and cause setpriv(1) to abort if AppArmor is not in use, and the transition may be
ignored or cause execve(2) to fail at AppArmor's whim.

--reset-env
Clears all the environment variables except TERM; initializes the environment
variables HOME, SHELL, USER, LOGNAME according to the user's passwd entry; sets
PATH to /usr/local/bin:/bin:/usr/bin for a regual user and to
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin for root.

The environment variable PATH may be different on systems where /bin and /sbin are
merged into /usr. The environment variable SHELL defaults to /bin/sh if none is
given in the user's passwd entry.

-V, --version
Display version information and exit.

-h, --help
Display help text and exit.

NOTES

       If  applying  any  specified option fails, program will not be run and setpriv will return
       with exit code 127.

       Be careful with this tool -- it may have unexpected security consequences.   For  example,
       setting  no_new_privs  and  then  execing a program that is SELinux-confined (as this tool
       would do) may prevent the SELinux restrictions from taking effect.

EXAMPLE

       If you're looking for behaviour similar to su(1)/runuser(1), or sudo(8)  (without  the  -g
       option), try something like:

           setpriv --reuid=1000 --regid=1000 --init-groups

       If you want to mimic daemontools' setuid(8), try:

           setpriv --reuid=1000 --regid=1000 --clear-groups

AUTHOR

       Andy Lutomirski ⟨luto@amacapital.net⟩

AVAILABILITY

       The  setpriv  command is part of the util-linux package and is available from Linux Kernel
       Archive ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.