1NEWUIDMAP(1)                     User Commands                    NEWUIDMAP(1)
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NAME

6       newuidmap - set the uid mapping of a user namespace
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SYNOPSIS

9       newuidmap pid uid loweruid count [uid loweruid count [ ... ]]
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DESCRIPTION

12       The newuidmap sets /proc/[pid]/uid_map based on its command line
13       arguments and the uids allowed. Subuid delegation can either be managed
14       via /etc/subuid or through the configured NSS subid module. These
15       options are mutually exclusive.
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17       Note that the root user is not exempted from the requirement for a
18       valid /etc/subuid entry.
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20       After the pid argument, newuidmap expects sets of 3 integers:
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22       uid
23           Beginning of the range of UIDs inside the user namespace.
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25       loweruid
26           Beginning of the range of UIDs outside the user namespace.
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28       count
29           Length of the ranges (both inside and outside the user namespace).
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31       newuidmap verifies that the caller is the owner of the process
32       indicated by pid and that for each of the above sets, each of the UIDs
33       in the range [loweruid, loweruid+count) is allowed to the caller
34       according to /etc/subuid before setting /proc/[pid]/uid_map.
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36       Note that newuidmap may be used only once for a given process.
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38       Instead of an integer process id, the first argument may be specified
39       as fd:N, where the integer N is the file descriptor number for the
40       calling process's opened file for /proc/[pid[. In this case, newuidmap
41       will use openat(2) to open the uid_map file under that directory,
42       avoiding a TOCTTOU in case the process exits and the pid is immediately
43       reused.
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OPTIONS

46       There currently are no options to the newuidmap command.
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FILES

49       /etc/subuid
50           List of user's subordinate user IDs.
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52       /proc/[pid]/uid_map
53           Mapping of uids from one between user namespaces.
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SEE ALSO

56       login.defs(5), newusers(8), subuid(5), useradd(8), usermod(8),
57       userdel(8).
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61shadow-utils 4.14.0               10/03/2023                      NEWUIDMAP(1)
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