newgidmap(1) — Linux manual page


NEWGIDMAP(1)                  User Commands                 NEWGIDMAP(1)

NAME         top

       newgidmap - set the gid mapping of a user namespace

SYNOPSIS         top

       newgidmap pid gid lowergid count [gid lowergid count [ ... ]]

DESCRIPTION         top

       The newgidmap sets /proc/[pid]/gid_map based on its command line
       arguments and the gids allowed. Subgid delegation can either be
       managed via /etc/subgid or through the configured NSS subid
       module. These options are mutually exclusive.

       Note that the root group is not exempted from the requirement for
       a valid /etc/subgid entry.

       After the pid argument, newgidmap expects sets of 3 integers:

           Beginning of the range of GIDs inside the user namespace.

           Beginning of the range of GIDs outside the user namespace.

           Length of the ranges (both inside and outside the user

       newgidmap verifies that the caller is the owner of the process
       indicated by pid and that for each of the above sets, each of the
       GIDs in the range [lowergid, lowergid+count) is allowed to the
       caller according to /etc/subgid before setting

       Note that newgidmap may be used only once for a given process.

       Instead of an integer process id, the first argument may be
       specified as fd:N, where the integer N is the file descriptor
       number for the calling process's opened file for /proc/[pid[. In
       this case, newgidmap will use openat(2) to open the gid_map file
       under that directory, avoiding a TOCTTOU in case the process
       exits and the pid is immediately reused.

OPTIONS         top

       There currently are no options to the newgidmap command.

FILES         top

           List of user's subordinate group IDs.

           Mapping of gids from one between user namespaces.

SEE ALSO         top

       login.defs(5), newusers(8), subgid(5), useradd(8), userdel(8),

COLOPHON         top

       This page is part of the shadow-utils (utilities for managing
       accounts and shadow password files) project.  Information about
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       ⟨⟩ on 2023-12-22.  (At that
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shadow-utils 4.11.1            12/22/2023                   NEWGIDMAP(1)

Pages that refer to this page: getsubids(1)unshare(1)mount_setattr(2)subgid(5)subuid(5)user_namespaces(7)