1ACCESS.CONF(5) Linux-PAM Manual ACCESS.CONF(5)
2
6 access.conf - the login access control table file
7
9 The /etc/security/access.conf file specifies (user/group, host),
10 (user/group, network/netmask), (user/group, tty), (user/group,
11 X-$DISPLAY-value), or (user/group, pam-service-name) combinations for
12 which a login will be either accepted or refused.
13 When someone logs in, the file access.conf is scanned for the first
15 entry that matches the (user/group, host) or (user/group,
16 network/netmask) combination, or, in case of non-networked logins, the
17 first entry that matches the (user/group, tty) combination, or in the
18 case of non-networked logins without a tty, the first entry that
19 matches the (user/group, X-$DISPLAY-value) or (user/group,
20 pam-service-name/) combination. The permissions field of that table
21 entry determines whether the login will be accepted or refused.
22 Each line of the login access control table has three fields separated
24 by a ":" character (colon):
25 permission:users/groups:origins
27 The first field, the permission field, can be either a "+" character
29 (plus) for access granted or a "-" character (minus) for access denied.
30 The second field, the users/group field, should be a list of one or
32 more login names, group names, or ALL (which always matches). To
33 differentiate user entries from group entries, group entries should be
34 written with brackets, e.g. (group).
35 The third field, the origins field, should be a list of one or more tty
37 names (for non-networked logins), X $DISPLAY values or PAM service
38 names (for non-networked logins without a tty), host names, domain
39 names (begin with "."), host addresses, internet network numbers (end
40 with "."), internet network addresses with network mask (where network
41 mask can be a decimal number or an internet address also), ALL (which
42 always matches) or LOCAL. The LOCAL keyword matches if and only if
43 pam_get_item(3), when called with an item_type of PAM_RHOST, returns
44 NULL or an empty string (and therefore the origins field is compared
45 against the return value of pam_get_item(3) called with an item_type of
46 PAM_TTY or, absent that, PAM_SERVICE).
47 If supported by the system you can use @netgroupname in host or user
49 patterns. The @@netgroupname syntax is supported in the user pattern
50 only and it makes the local system hostname to be passed to the
51 netgroup match call in addition to the user name. This might not work
52 correctly on some libc implementations causing the match to always
53 fail.
54 The EXCEPT operator makes it possible to write very compact rules.
56 If the nodefgroup is not set, the group file is searched when a name
58 does not match that of the logged-in user. Only groups are matched in
59 which users are explicitly listed. However the PAM module does not look
60 at the primary group id of a user.
61 The "#" character at start of line (no space at front) can be used to
63 mark this line as a comment line.
64
66 These are some example lines which might be specified in
67 /etc/security/access.conf.
68 User root should be allowed to get access via cron, X11 terminal :0,
70 tty1, ..., tty5, tty6.
71 +:root:crond :0 tty1 tty2 tty3 tty4 tty5 tty6
73 User root should be allowed to get access from hosts which own the IPv4
75 addresses. This does not mean that the connection have to be a IPv4
76 one, a IPv6 connection from a host with one of this IPv4 addresses does
77 work, too.
78 +:root:192.168.200.1 192.168.200.4 192.168.200.9
80 +:root:127.0.0.1
82 User root should get access from network 192.168.201. where the term
84 will be evaluated by string matching. But it might be better to use
85 network/netmask instead. The same meaning of 192.168.201. is
86 192.168.201.0/24 or 192.168.201.0/255.255.255.0.
87 +:root:192.168.201.
89 User root should be able to have access from hosts foo1.bar.org and
91 foo2.bar.org (uses string matching also).
92 +:root:foo1.bar.org foo2.bar.org
94 User root should be able to have access from domain foo.bar.org (uses
96 string matching also).
97 +:root:.foo.bar.org
99 User root should be denied to get access from all other sources.
101 -:root:ALL
103 User foo and members of netgroup admins should be allowed to get access
105 from all sources. This will only work if netgroup service is available.
106 +:@admins foo:ALL
108 User john and foo should get access from IPv6 host address.
110 +:john foo:2001:db8:0:101::1
112 User john should get access from IPv6 net/mask.
114 +:john:2001:db8:0:101::/64
116 Members of group wheel should be allowed to get access from all
118 sources.
119 +:(wheel):ALL
121 Disallow console logins to all but the shutdown, sync and all other
123 accounts, which are a member of the wheel group.
124 -:ALL EXCEPT (wheel) shutdown sync:LOCAL
126 All other users should be denied to get access from all sources.
128 -:ALL:ALL
130
132 The default separators of list items in a field are space, ',', and
133 tabulator characters. Thus conveniently if spaces are put at the
134 beginning and the end of the fields they are ignored. However if the
135 list separator is changed with the listsep option, the spaces will
136 become part of the actual item and the line will be most probably
137 ignored. For this reason, it is not recommended to put spaces around
138 the ':' characters.
139
141 pam_access(8), pam.d(5), pam(8)
142
144 Original login.access(5) manual was provided by Guido van Rooij which
145 was renamed to access.conf(5) to reflect relation to default config
146 file.
147 Network address / netmask description and example text was introduced
149 by Mike Becher <mike.becher@lrz-muenchen.de>.
150Linux-PAM Manual 09/03/2021 ACCESS.CONF(5)