1SETPRIV(1)                       User Commands                      SETPRIV(1)
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NAME

6       setpriv - run a program with different Linux privilege settings
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SYNOPSIS

9       setpriv [options] program [arguments]
10

DESCRIPTION

12       Sets or queries various Linux privilege settings that are inherited
13       across execve(2).
14
15       In comparison to su(1) and runuser(1), setpriv neither uses PAM, nor
16       does it prompt for a password. It is a simple, non-set-user-ID wrapper
17       around execve(2), and can be used to drop privileges in the same way as
18       setuidgid(8) from daemontools, chpst(8) from runit, or similar tools
19       shipped by other service managers.
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OPTIONS

22       --clear-groups
23           Clear supplementary groups.
24
25       -d, --dump
26           Dump the current privilege state. This option can be specified more
27           than once to show extra, mostly useless, information. Incompatible
28           with all other options.
29
30       --groups group...
31           Set supplementary groups. The argument is a comma-separated list of
32           GIDs or names.
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34       --inh-caps (+|-)cap..., --ambient-caps (+|-)cap..., --bounding-set
35       (+|-)cap...
36           Set the inheritable capabilities, ambient capabilities or the
37           capability bounding set. See capabilities(7). The argument is a
38           comma-separated list of +cap and -cap entries, which add or remove
39           an entry respectively. cap can either be a human-readable name as
40           seen in capabilities(7) without the cap_ prefix or of the format
41           cap_N, where N is the internal capability index used by Linux. +all
42           and -all can be used to add or remove all caps.
43
44           The set of capabilities starts out as the current inheritable set
45           for --inh-caps, the current ambient set for --ambient-caps and the
46           current bounding set for --bounding-set.
47
48           Note the following restrictions (detailed in capabilities(7))
49           regarding modifications to these capability sets:
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51           •   A capability can be added to the inheritable set only if it is
52               currently present in the bounding set.
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54           •   A capability can be added to the ambient set only if it is
55               currently present in both the permitted and inheritable sets.
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57           •   Notwithstanding the syntax offered by setpriv, the kernel does
58               not permit capabilities to be added to the bounding set.
59
60       If you drop a capability from the bounding set without also dropping it
61       from the inheritable set, you are likely to become confused. Do not do
62       that.
63
64       --keep-groups
65           Preserve supplementary groups. Only useful in conjunction with
66           --rgid, --egid, or --regid.
67
68       --init-groups
69           Initialize supplementary groups using initgroups3. Only useful in
70           conjunction with --ruid or --reuid.
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72       --list-caps
73           List all known capabilities. This option must be specified alone.
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75       --no-new-privs
76           Set the no_new_privs bit. With this bit set, execve(2) will not
77           grant new privileges. For example, the set-user-ID and set-group-ID
78           bits as well as file capabilities will be disabled. (Executing
79           binaries with these bits set will still work, but they will not
80           gain privileges. Certain LSMs, especially AppArmor, may result in
81           failures to execute certain programs.) This bit is inherited by
82           child processes and cannot be unset. See prctl(2) and
83           Documentation/prctl/no_new_privs.txt in the Linux kernel source.
84
85           The no_new_privs bit is supported since Linux 3.5.
86
87       --rgid gid, --egid gid, --regid gid
88           Set the real, effective, or both GIDs. The gid argument can be
89           given as a textual group name.
90
91           For safety, you must specify one of --clear-groups, --groups,
92           --keep-groups, or --init-groups if you set any primary gid.
93
94       --ruid uid, --euid uid, --reuid uid
95           Set the real, effective, or both UIDs. The uid argument can be
96           given as a textual login name.
97
98           Setting a uid or gid does not change capabilities, although the
99           exec call at the end might change capabilities. This means that, if
100           you are root, you probably want to do something like:
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102           setpriv --reuid=1000 --regid=1000 --inh-caps=-all
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104       --securebits (+|-)securebit...
105           Set or clear securebits. The argument is a comma-separated list.
106           The valid securebits are noroot, noroot_locked, no_setuid_fixup,
107           no_setuid_fixup_locked, and keep_caps_locked. keep_caps is cleared
108           by execve(2) and is therefore not allowed.
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110       --pdeathsig keep|clear|<signal>
111           Keep, clear or set the parent death signal. Some LSMs, most notably
112           SELinux and AppArmor, clear the signal when the process'
113           credentials change. Using --pdeathsig keep will restore the parent
114           death signal after changing credentials to remedy that situation.
115
116       --selinux-label label
117           Request a particular SELinux transition (using a transition on
118           exec, not dyntrans). This will fail and cause setpriv to abort if
119           SELinux is not in use, and the transition may be ignored or cause
120           execve(2) to fail at SELinux’s whim. (In particular, this is
121           unlikely to work in conjunction with no_new_privs.) This is similar
122           to runcon(1).
123
124       --apparmor-profile profile
125           Request a particular AppArmor profile (using a transition on exec).
126           This will fail and cause setpriv to abort if AppArmor is not in
127           use, and the transition may be ignored or cause execve(2) to fail
128           at AppArmor’s whim.
129
130       --reset-env
131           Clears all the environment variables except TERM; initializes the
132           environment variables HOME, SHELL, USER, LOGNAME according to the
133           user’s passwd entry; sets PATH to /usr/local/bin:/bin:/usr/bin for
134           a regular user and to
135           /usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin for
136           root.
137
138           The environment variable PATH may be different on systems where
139           /bin and /sbin are merged into /usr. The environment variable SHELL
140           defaults to /bin/sh if none is given in the user’s passwd entry.
141
142       -h, --help
143           Display help text and exit.
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145       -V, --version
146           Print version and exit.
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NOTES

149       If applying any specified option fails, program will not be run and
150       setpriv will return with exit status 127.
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152       Be careful with this tool — it may have unexpected security
153       consequences. For example, setting no_new_privs and then execing a
154       program that is SELinux-confined (as this tool would do) may prevent
155       the SELinux restrictions from taking effect.
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EXAMPLES

158       If you’re looking for behavior similar to su(1)/runuser(1), or sudo(8)
159       (without the -g option), try something like:
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161       setpriv --reuid=1000 --regid=1000 --init-groups
162
163       If you want to mimic daemontools' setuid(8), try:
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165       setpriv --reuid=1000 --regid=1000 --clear-groups
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AUTHORS

168       Andy Lutomirski <luto@amacapital.net>
169

SEE ALSO

171       runuser(1), su(1), prctl(2), capabilities(7)
172

REPORTING BUGS

174       For bug reports, use the issue tracker at
175       https://github.com/util-linux/util-linux/issues.
176

AVAILABILITY

178       The setpriv command is part of the util-linux package which can be
179       downloaded from Linux Kernel Archive
180       <https://www.kernel.org/pub/linux/utils/util-linux/>.
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184util-linux 2.38                   2022-02-17                        SETPRIV(1)
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