setpriv(1) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | NOTES | EXAMPLES | AUTHORS | SEE ALSO | AVAILABILITY | COLOPHON

SETPRIV(1)                    User Commands                   SETPRIV(1)

NAME         top

       setpriv - run a program with different Linux privilege settings

SYNOPSIS         top

       setpriv [options] program [arguments]

DESCRIPTION         top

       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         top

       --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...  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.

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

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

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

              * 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 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 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         top

       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         top

       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

AUTHORS         top

       Andy Lutomirski ⟨luto@amacapital.net⟩

SEE ALSO         top

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

AVAILABILITY         top

       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/⟩.

COLOPHON         top

       This page is part of the util-linux (a random collection of Linux
       utilities) project.  Information about the project can be found
       at ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.  If you
       have a bug report for this manual page, send it to
       util-linux@vger.kernel.org.  This page was obtained from the
       project's upstream Git repository
       ⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
       2021-03-21.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-03-19.)  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

util-linux                      July 2014                     SETPRIV(1)

Pages that refer to this page: runuser(1)su(1)capabilities(7)credentials(7)