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:

           •   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 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.

       --landlock-access access
           Enable landlock restrictions for a specific set of system accesses. To allow specific subgroups of
           accesses use --landlock-rule.

           Block all filesystem access:

           setpriv --landlock-access fs

           Block all file deletions and directory creations:

           setpriv --landlock-access fs:remove-file,make-dir

           For a complete set of supported access categories use setpriv --help.

       --landlock-rule rule
           Allow one specific access from the categories blocked by --landlock-access.

           The syntax is as follows:

           --landlock-rule $ruletype:$access:$rulearg

           For example grant file read access to everything under /boot:

           --landlock-rule path-beneath:read-file:/boot

       --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.

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

       -V, --version
           Print version 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) landlock(7)

REPORTING BUGS

       For bug reports, use the issue tracker at https://github.com/util-linux/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/>.