setpriv

SETPRIV(1)                       User Commands                      SETPRIV(1)

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 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.

OPTIONS
       --clear-groups
           Clear supplementary groups.

       -d, --dump
           Dump the current privilege state. This option 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..., --ambient-caps (+|-)cap..., --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.

           Note the following restrictions (detailed in capabilities(7))
           regarding modifications to these capability sets:

           o   A capability can be added to the inheritable set only if it is
               currently present in the bounding set.

           o   A capability can be added to the ambient set only if it is
               currently present in both the permitted and inheritable sets.

           o   Notwithstanding the syntax offered by setpriv, the kernel does
               not permit capabilities to be added to the bounding set.

       If you drop a capability 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 initgroups3. 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 a 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 a 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 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 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 regular 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 status 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.

EXAMPLES
       If you're looking for behavior 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

AUTHORS
       Andy Lutomirski <luto@amacapital.net>

SEE ALSO
       runuser(1), su(1), prctl(2), capabilities(7)

REPORTING BUGS
       For bug reports, use the issue tracker at
       https://github.com/karelzak/util-linux/issues.

AVAILABILITY
       The setpriv command is part of the util-linux package which can be
       downloaded from Linux Kernel Archive
       <https://www.kernel.org/pub/linux/utils/util-linux/>.

util-linux 2.37.2                 2021-06-02                        SETPRIV(1)