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(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

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

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/⟩.



util-linux                         July 2014                        SETPRIV(1)