Man page - subgid(5)

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Package:  passwd
apt-get install passwd

Manuals in package:
• chsh(1)
• gpasswd(1)
• gshadow(5)
• groupmod(8)
• grpconv(8)
• usermod(8)
• passwd(1)
• grpunconv(8)
• subgid(5)
• vipw(8)
• pwck(8)
• useradd(8)
• expiry(1)
• chfn(1)
• chage(1)
• pwconv(8)
• groupadd(8)
• passwd(5)
• subuid(5)
• vigr(8)
• chgpasswd(8)
• shadowconfig(8)
• groupdel(8)
• pwunconv(8)
• shadow(5)
• chpasswd(8)
• newusers(8)
• grpck(8)
• userdel(8)
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Manual

SUBGID

NOM
DESCRIPTION
LOCAL SUBORDINATE DELEGATION
FICHIERS
VOIR AUSSI

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NOM

subgid - the configuration for subordinate group ids

DESCRIPTION

Subgid authorizes a group id to map ranges of group ids from its namespace into child namespaces.

The delegation of the subordinate gids can be configured via the subid field in /etc/nsswitch.conf file. Only one value can be set as the delegation source. Setting this field to files configures the delegation of gids to /etc/subgid. Setting any other value treats the delegation as a plugin following with a name of the form libsubid_$value.so . If the value or plugin is missing, then the subordinate gid delegation falls back to files .

Note, that newusers , useradd , and usermod will only create entries in /etc/subgid if subid delegation is managed via subid files.

LOCAL SUBORDINATE DELEGATION

Each line in /etc/subgid contains a user name and a range of subordinate group ids that user is allowed to use. This is specified with three fields delimited by colons (« : »). These fields are:

• login name or UID

• numerical subordinate group ID

• numerical subordinate group ID count

This file specifies the group IDs that ordinary users can use, with the newgidmap command, to configure gid mapping in a user namespace.

Multiple ranges may be specified per user.

When large number of entries (10000-100000 or more) are defined in /etc/subgid, parsing performance penalty will become noticeable. In this case it is recommended to use UIDs instead of login names. Benchmarks have shown speed-ups up to 20x.

FICHIERS

/etc/subgid

IDs des groupes subalternes d'un utilisateur.

/etc/subgid-

Backup file for /etc/subgid.

VOIR AUSSI

login.defs (5), newgidmap (1), newuidmap (1), newusers (8), subuid (5), useradd (8), userdel (8), usermod (8), user_namespaces (7).

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