153 lines
4.3 KiB
Plaintext
153 lines
4.3 KiB
Plaintext
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(*
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Module: Hosts_Access
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Parses /etc/hosts.{allow,deny}
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Author: Raphael Pinson <raphink@gmail.com>
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About: Reference
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This lens tries to keep as close as possible to `man 5 hosts_access` and `man 5 hosts_options` where possible.
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About: License
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This file is licenced under the LGPL v2+, like the rest of Augeas.
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About: Lens Usage
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To be documented
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About: Configuration files
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This lens applies to /etc/hosts.{allow,deny}. See <filter>.
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*)
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module Hosts_Access =
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autoload xfm
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(************************************************************************
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* Group: USEFUL PRIMITIVES
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*************************************************************************)
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(* View: colon *)
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let colon = del /[ \t]*(\\\\[ \t]*\n[ \t]+)?:[ \t]*(\\\\[ \t]*\n[ \t]+)?/ ": "
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(* Variable: comma_sep *)
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let comma_sep = /([ \t]|(\\\\\n))*,([ \t]|(\\\\\n))*/
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(* Variable: ws_sep *)
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let ws_sep = / +/
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(* View: list_sep *)
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let list_sep = del ( comma_sep | ws_sep ) ", "
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(* View: list_item *)
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let list_item = store ( Rx.word - /EXCEPT/i )
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(* View: client_host_item
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Allows @ for netgroups, supports [ipv6] syntax *)
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let client_host_item =
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let client_hostname_rx = /[A-Za-z0-9_.@?*-][A-Za-z0-9_.?*-]*/ in
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let client_ipv6_rx = "[" . /[A-Za-z0-9:?*%]+/ . "]" in
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let client_host_rx = client_hostname_rx | client_ipv6_rx in
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let netmask = [ Util.del_str "/" . label "netmask" . store Rx.word ] in
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store ( client_host_rx - /EXCEPT/i ) . netmask?
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(* View: client_file_item *)
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let client_file_item =
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let client_file_rx = /\/[^ \t\n,:]+/ in
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store ( client_file_rx - /EXCEPT/i )
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(* Variable: option_kw
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Since either an option or a shell command can be given, use an explicit list
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of known options to avoid misinterpreting a command as an option *)
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let option_kw = "severity"
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| "spawn"
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| "twist"
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| "keepalive"
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| "linger"
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| "rfc931"
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| "banners"
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| "nice"
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| "setenv"
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| "umask"
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| "user"
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| /allow/i
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| /deny/i
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(* Variable: shell_command_rx *)
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let shell_command_rx = /[^ \t\n:][^\n]*[^ \t\n]|[^ \t\n:\\\\]/
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- ( option_kw . /.*/ )
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(* View: sto_to_colon
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Allows escaped colon sequences *)
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let sto_to_colon = store /[^ \t\n:=][^\n:]*((\\\\:|\\\\[ \t]*\n[ \t]+)[^\n:]*)*[^ \\\t\n:]|[^ \t\n:\\\\]/
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(* View: except
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* The except operator makes it possible to write very compact rules.
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*)
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let except (lns:lens) = [ label "except" . Sep.space
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. del /except/i "EXCEPT"
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. Sep.space . lns ]
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(************************************************************************
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* Group: ENTRY TYPES
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*************************************************************************)
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(* View: daemon *)
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let daemon =
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let host = [ label "host"
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. Util.del_str "@"
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. list_item ] in
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[ label "process"
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. list_item
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. host? ]
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(* View: daemon_list
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A list of <daemon>s *)
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let daemon_list = Build.opt_list daemon list_sep
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(* View: client *)
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let client =
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let user = [ label "user"
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. list_item
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. Util.del_str "@" ] in
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[ label "client"
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. user?
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. client_host_item ]
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(* View: client_file *)
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let client_file = [ label "file" . client_file_item ]
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(* View: client_list
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A list of <client>s *)
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let client_list = Build.opt_list ( client | client_file ) list_sep
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(* View: option
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Optional extensions defined in hosts_options(5) *)
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let option = [ key option_kw
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. ( del /([ \t]*=[ \t]*|[ \t]+)/ " " . sto_to_colon )? ]
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(* View: shell_command *)
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let shell_command = [ label "shell_command"
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. store shell_command_rx ]
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(* View: entry *)
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let entry = [ seq "line"
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. daemon_list
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. (except daemon_list)?
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. colon
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. client_list
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. (except client_list)?
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. ( (colon . option)+ | (colon . shell_command)? )
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. Util.eol ]
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(************************************************************************
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* Group: LENS AND FILTER
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*************************************************************************)
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(* View: lns *)
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let lns = (Util.empty | Util.comment | entry)*
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(* View: filter *)
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let filter = incl "/etc/hosts.allow"
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. incl "/etc/hosts.deny"
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let xfm = transform lns filter
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