nbdkit-ip-filter(1)

1nbdkit-ip-filter(1)                 NBDKIT                 nbdkit-ip-filter(1)
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NAME

6       nbdkit-ip-filter - filter clients by IP address, process ID, user ID or
7       group ID
8

SYNOPSIS

10        nbdkit --filter=ip PLUGIN [allow=addr[,addr...]]
11                                  [deny=addr[,addr...]]
12

DESCRIPTION

14       "nbdkit-ip-filter" can allow or deny client connections by their IP
15       address.  Usually it is better to control this outside nbdkit, for
16       example using TCP wrappers or a firewall, but this filter can be used
17       if these are not available.
18
19       nbdkit ≥ 1.24 added the ability to filter clients connecting over Unix
20       domain sockets by client process ID, user ID and group ID.  Also this
21       version added support for filtering "AF_VSOCK" sockets by peer CID or
22       port.
23

EXAMPLES

25   Filter by IP address
26        nbdkit --filter=ip [...] allow=127.0.0.1,::1 deny=all
27
28       Allow clients to connect on the loopback IPv4 or loopback IPv6 address,
29       deny all other clients.
30
31        nbdkit --filter=ip [...] deny=8.0.0.0/8
32
33       Allow any client except connections from the IPv4 "8.0.0.0/8" network.
34
35        nbdkit --filter=ip [...] allow=anyipv6 deny=all
36
37       Allow IPv6 clients to connect from anywhere, deny all other sources.
38
39   Filter by Unix domain socket peer
40        nbdkit -U $tmpdir/sock --filter=ip [...] allow=uid:`id -u` deny=all
41
42       Only allow the current user ("id -u") to connect over the socket.
43
44       Layer extra security by creating the socket inside a temporary
45       directory only accessible by the user.
46
47        nbdkit -U $tmpdir/sock --filter=ip [...] allow=gid:`id -g` deny=all
48
49       Allow anyone in the same group as the current user to connect to the
50       Unix domain socket.
51
52       As in the previous example, layer extra security by creating the socket
53       inside a temporary directory only accessible by the group.
54

RULES

56       When a client connects, this filter checks its source address against
57       the allow and deny lists as follows:
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59       1.  If the address matches any in the allow list, permission is
60           granted.
61
62       2.  If the address matches any in the deny list, permission is denied.
63
64       3.  Otherwise permission is granted.
65
66       If either the "allow" or "deny" parameter is not present then it is
67       assumed to be an empty list.  The order in which the parameters appear
68       on the command line does not matter; the allow list is always processed
69       first and the deny list second.
70
71       The "allow" and "deny" parameters each contain a comma-separated list
72       of any of the following:
73
74       all
75       any These keywords (which both have the same meaning) match any source.
76
77       allipv4
78       anyipv4
79           These keywords match any IPv4 address.
80
81       allipv6
82       anyipv6
83           These keywords match any IPv6 address.
84
85       allunix
86       anyunix
87           These keywords match any connection over a Unix domain socket.
88
89       allvsock
90       anyvsock
91           These keywords match any connection over an "AF_VSOCK" socket.
92
93       A.B.C.D
94           This matches the single IPv4 address "A.B.C.D", for example
95           127.0.0.1.
96
97       A.B.C.D/NN
98           This matches the range of IPv4 addresses "A.B.C.D/NN", for example
99           "192.168.2.0/24" or "10.0.0.0/8".
100
101       A:B:...
102           This matches the single IPv6 address "A:B:...".  The usual IPv6
103           address representations can be used (see RFC 5952).
104
105       A:B:.../NN
106           This matches a range of IPv6 addresses "A:B:.../NN".
107
108       pid:PID
109           (nbdkit ≥ 1.24, Linux only)
110
111           This matches the process ID "PID", if the client connects over a
112           Unix domain socket.
113
114           Note that process IDs are recycled so this alone is not secure
115           enough to ensure that only a single desired process can connect.
116           However you could use it as an additional check.
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118       uid:UID
119           (nbdkit ≥ 1.24)
120
121           This matches the numeric user ID "UID", if the client connects over
122           a Unix domain socket.
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124       gid:GID
125           (nbdkit ≥ 1.24)
126
127           This matches the numeric group ID "GID", if the client connects
128           over a Unix domain socket.
129
130       vsock-cid:CID
131       vsock-port:PORT
132           (nbdkit ≥ 1.24)
133
134           These match the CID or port number for "AF_VSOCK" sockets.
135
136   Not filtered
137       If neither the "allow" nor the "deny" parameter is given the filter
138       does nothing.
139
140       Unix domain sockets and "AF_VSOCK" sockets were always unfiltered in
141       nbdkit ≤ 1.22.  In nbdkit ≥ 1.24 the ability to filter them was added.
142
143   Common patterns of usage
144       Permit known good connections and deny everything else:
145
146        nbdkit --filter=ip ... allow=good1,good2,... deny=all
147
148       Block troublemakers but allow everything else:
149
150        nbdkit --filter=ip ... deny=bad1,bad2,...
151

PARAMETERS

153       allow=addr[,...]
154           Set list of allow rules.  This parameter is optional, if omitted
155           the allow list is empty.
156
157       deny=addr[,...]
158           Set list of deny rules.  This parameter is optional, if omitted the
159           deny list is empty.
160

FILES

162       $filterdir/nbdkit-ip-filter.so
163           The filter.
164
165           Use "nbdkit --dump-config" to find the location of $filterdir.
166

VERSION

168       "nbdkit-ip-filter" first appeared in nbdkit 1.18.
169

AUTHORS

175       Richard W.M. Jones
176

COPYRIGHT

178       Copyright (C) 2019-2020 Red Hat Inc.
179

LICENSE

181       Redistribution and use in source and binary forms, with or without
182       modification, are permitted provided that the following conditions are
183       met:
184
185       •   Redistributions of source code must retain the above copyright
186           notice, this list of conditions and the following disclaimer.
187
188       •   Redistributions in binary form must reproduce the above copyright
189           notice, this list of conditions and the following disclaimer in the
190           documentation and/or other materials provided with the
191           distribution.
192
193       •   Neither the name of Red Hat nor the names of its contributors may
194           be used to endorse or promote products derived from this software
195           without specific prior written permission.
196
197       THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS IS'' AND ANY
198       EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
199       IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
200       PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR CONTRIBUTORS BE
201       LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
202       CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
203       SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
204       BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
205       WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
206       OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
207       ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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211nbdkit-1.32.5                     2023-01-03               nbdkit-ip-filter(1)