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
       2020-08-13.  (At that time, the date of the most recent commit that
       was found in the repository was 2020-08-12.)  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)