setpriv man page

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).

The difference between the commands setpriv and su (or runuser) is that setpriv does not use open PAM session and does not ask for password. It's simple non-suid wrapper around execve syscall.

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.
--inh-caps (+|-)cap... or --bounding-set (+|-)cap...
Set the inheritable 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. +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 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.
--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 setuid and setgid 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, or --keep-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 --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.
--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.
-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.

See Also

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

Author

Andy Lutomirski

Availability

The setpriv command is part of the util-linux package and is available from Linux Kernel Archive.

Referenced By

capabilities(7), runuser(1), su(1).

July 2014 util-linux User Commands