firewall: fix generation of outgoing rules on webserver
[hcoop/domtool2.git] / src / plugins / firewall.sml
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1(* HCoop Domtool (http://hcoop.sourceforge.net/)
2 * Copyright (c) 2006-2007, Adam Chlipala
93278775 3 * Copyright (c) 2011,2012,2013,2014,2018 Clinton Ebadi
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4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version 2
8 * of the License, or (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 *)
19
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20(* Firewall management *)
21
22(* Contains portions from Fwtool Copyright (C) 2005 Adam Chlipala, GPL v2 or later *)
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23
24structure Firewall :> FIREWALL = struct
25
1a03ee46 26datatype user = User of string
93278775 27
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28datatype fwnode = FirewallNode of string
29
30datatype fwrule = Client of int list * string list
31 | Server of int list * string list
32 | ProxiedServer of int list
33 | LocalServer of int list
34
35type firewall_rules = (user * fwnode * fwrule) list
73b95423 36
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37datatype fwip = FwIPv4
38 | FwIPv6
39
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40structure StringMap = DataStructures.StringMap
41
9a8de137 42fun parseRules () =
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43 let
44 val inf = TextIO.openIn Config.Firewall.firewallRules
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45
46 fun parsePorts ports =
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47 List.mapPartial Int.fromString (String.fields (fn ch => ch = #",") ports)
48 (* Just drop bad ports for now *)
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49
50 fun parseNodes nodes = String.fields (fn ch => ch = #",") nodes
51
1a03ee46 52 fun loop parsedRules =
ec95f39f 53 case TextIO.inputLine inf of
1a03ee46 54 NONE => parsedRules
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55 | SOME line =>
56 case String.tokens Char.isSpace line of
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57 nodes :: uname :: rest =>
58 let
59 val nodes = parseNodes nodes
60 in
61 case rest of
62 "Client" :: ports :: hosts => loop (map (fn node => (User uname, FirewallNode node, Client (parsePorts ports, hosts))) nodes) @ parsedRules
63 | "Server" :: ports :: hosts => loop (map (fn node => (User uname, FirewallNode node, Server (parsePorts ports, hosts))) nodes) @ parsedRules
64 | ["ProxiedServer", ports] => loop (map (fn node => (User uname, FirewallNode node, ProxiedServer (parsePorts ports))) nodes) @ parsedRules
65 | ["LocalServer", ports] => loop (map (fn node => (User uname, FirewallNode node, LocalServer (parsePorts ports))) nodes) @ parsedRules
66 | _ => (print "Invalid config line\n"; loop parsedRules)
67 end
1a03ee46 68 | _ => loop parsedRules
ec95f39f 69 in
1a03ee46 70 loop []
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71 end
72
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73fun formatQueryRule (Client (ports, hosts)) =
74 "Client " ^ String.concatWith "," (map Int.toString ports) ^ " " ^ String.concatWith " " hosts
75 | formatQueryRule (Server (ports, hosts)) =
76 "Server " ^ String.concatWith "," (map Int.toString ports) ^ " " ^ String.concatWith " " hosts
77 | formatQueryRule (ProxiedServer ports) =
78 "ProxiedServer " ^ String.concatWith "," (map Int.toString ports)
79 | formatQueryRule (LocalServer ports) =
80 "LocalServer " ^ String.concatWith "," (map Int.toString ports)
81
82fun query (node, uname) =
1a03ee46 83 (* completely broken *)
f9548f16 84 let
ec95f39f 85 val rules = parseRules ()
f9548f16 86 in
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87 map (fn (_, _, r) => formatQueryRule r)
88 (List.filter (fn (User u, FirewallNode n, _) => u = uname andalso n = node) rules)
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89 end
90
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91fun dnsExists dnsRR dnsRecord =
92 let
93 val dnsRR_string = case dnsRR of
94 FwIPv6 => "AAAA"
95 | FwIPv4 => "A"
96 in
97 (* timeout chosen arbitrarilty, shorter is better if it's reliable *)
98 (* dig outputs true even if the lookup fails, but no output in short mode should work *)
99 case Slave.runOutput (Config.Firewall.dig, ["+short", "+timeout=3", "-t", dnsRR_string, dnsRecord]) of
100 (_, SOME s) => (case Domain.validDomain (substring (s, 0, size s - 2)) of (* delete trailing . from cname *)
101 true => dnsExists dnsRR s (* dig will return CNAME, must recurse *)
102 | false => true) (* maybe also double check ip? use size s - 1 if so! *)
103
104 | (_, NONE) => false
105 end
106
794c19ea 107fun fermVariable x = String.isPrefix "$" x
93278775 108fun filterHosts (hosts, ipv6) =
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109 List.filter (fn host => fermVariable host
110 orelse (case ipv6 of FwIPv6 => Domain.validIpv6 host
111 | FwIPv4 => Domain.validIp host)
112 orelse dnsExists ipv6 host)
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113 hosts
114
115
1a03ee46 116fun formatPorts ports = "(" ^ String.concatWith " " (map Int.toString ports) ^ ")"
93278775 117fun formatHosts (hosts, ipv6) = "(" ^ String.concatWith " " (filterHosts (hosts, ipv6)) ^ ")"
1a03ee46 118
93278775 119fun formatOutputRule (Client (ports, hosts), ipv6) = "dport " ^ formatPorts ports ^ (case hosts of
1a03ee46 120 [] => ""
93278775 121 | _ => " daddr " ^ formatHosts (hosts, ipv6)) ^ " ACCEPT;"
f3b84aff 122 | formatOutputRule _ = ""
1a03ee46 123
93278775 124fun formatInputRule (Server (ports, hosts), ipv6) = "dport " ^ formatPorts ports ^ (case hosts of
1a03ee46 125 [] => ""
93278775 126 | _ => " saddr " ^ formatHosts (hosts, ipv6)) ^ " ACCEPT;"
f3b84aff 127 | formatInputRule _ = ""
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128
129type ferm_lines = { input_rules : (string list) DataStructures.StringMap.map,
93278775 130 output_rules : (string list) DataStructures.StringMap.map }
1a03ee46 131
93278775 132fun generateNodeFermRules rules =
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133 let
134 fun filter_node_rules rules =
93278775 135 List.filter (fn (uname, FirewallNode node, rule) => node = Slave.hostname () orelse case rule of
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136 ProxiedServer _ => List.exists (fn (h,_) => h = Slave.hostname ()) Config.Apache.webNodes_all
137 | _ => false)
138 rules
f9548f16 139
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140 val inputLines = ref StringMap.empty
141 val outputLines = ref StringMap.empty
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142 val inputLines_v6 = ref StringMap.empty
143 val outputLines_v6 = ref StringMap.empty
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144
145 fun confLine r (User uname, line) =
146 let
147 val line = "\t" ^ line ^ "\n"
148 val lines = case StringMap.find (!r, uname) of
149 NONE => []
150 | SOME lines => lines
151 in
152 r := StringMap.insert (!r, uname, line :: lines)
153 end
154
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155 fun confLine_in (uname, rule) = confLine inputLines (uname, formatInputRule (rule, FwIPv4))
156 fun confLine_out (uname, rule) = confLine outputLines (uname, formatOutputRule (rule, FwIPv4))
157 fun confLine_in_v6 (uname, rule) = confLine inputLines_v6 (uname, formatInputRule (rule, FwIPv6))
158 fun confLine_out_v6 (uname, rule) = confLine outputLines_v6 (uname, formatOutputRule (rule, FwIPv6))
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159
160 fun insertConfLine (uname, ruleNode, rule) =
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161 let
162 val fwnode_domain = fn FirewallNode node => node ^ "." ^ Config.defaultDomain
163 in
164 case rule of
165 Client (ports, hosts) => (confLine_out (uname, rule); confLine_out_v6 (uname, rule))
166 | Server (ports, hosts) => (confLine_in (uname, rule); confLine_in_v6 (uname, rule))
167 | LocalServer ports => (insertConfLine (uname, ruleNode, Client (ports, ["127.0.0.1/8"]));
168 insertConfLine (uname, ruleNode, Server (ports, ["127.0.0.1/8"]));
169 insertConfLine (uname, ruleNode, Client (ports, [":::1"]));
170 insertConfLine (uname, ruleNode, Server (ports, [":::1"])))
171 | ProxiedServer ports => if (fn FirewallNode r => r) ruleNode = Slave.hostname () then
172 (insertConfLine (uname, ruleNode, Server (ports, ["$WEBNODES"]));
173 insertConfLine (uname, ruleNode, Client (ports, [fwnode_domain ruleNode])))
174 else (* we are a web server *)
175 (insertConfLine (uname, ruleNode, Client (ports, [fwnode_domain ruleNode]));
176 insertConfLine (User "www-data", ruleNode, Client (ports, [fwnode_domain ruleNode])))
177 end
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178
179 val _ = map insertConfLine (filter_node_rules rules)
180 in
181 { input_rules = !inputLines,
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182 output_rules = !outputLines,
183 input6_rules = !inputLines_v6,
184 output6_rules = !outputLines_v6 }
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185
186
187 end
188
189fun generateFirewallConfig rules =
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190 (* rule generation must happen on the node (mandating the even
191 service users be pts users would make it possible to do on the
192 server, but that's not happening any time soon) *)
ec95f39f 193 let
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194 val users_tcp_out_conf = TextIO.openOut (Config.Firewall.firewallDir ^ "/users_tcp_out.conf")
195 val users_tcp_in_conf = TextIO.openOut (Config.Firewall.firewallDir ^ "/users_tcp_in.conf")
1a03ee46 196
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197 val users_tcp6_out_conf = TextIO.openOut (Config.Firewall.firewallDir ^ "/users_tcp6_out.conf")
198 val users_tcp6_in_conf = TextIO.openOut (Config.Firewall.firewallDir ^ "/users_tcp6_in.conf")
93278775 199
1a03ee46 200 val nodeFermRules = generateNodeFermRules rules
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201
202 fun write_tcp_in_conf_preamble outf =
203 (* no ipv6 support yet, but use @ipfilter() in ferm to prepare *)
204 TextIO.output (outf, String.concat ["@def $WEBNODES = @ipfilter((",
205 (String.concatWith " " (List.map (fn (_, ip) => ip)
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206 (List.filter (fn (node, _) => List.exists (fn (n) => n = node) (List.map (fn (node, _) => node) (Config.Apache.webNodes_all @ Config.Apache.webNodes_admin)))
207 Config.nodeIps))),
93278775 208 "));\n\n"])
1a03ee46 209
93278775 210 fun writeUserInRules tcp_inf (uname, lines) =
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211 (* We can't match the user when listening; SELinux or
212 similar would let us manage this with better
213 granularity.*)
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214 let
215 val _ = SysWord.toInt (Posix.ProcEnv.uidToWord (Posix.SysDB.Passwd.uid (Posix.SysDB.getpwnam uname)))
216 in
1933c596 217 TextIO.output (tcp_inf, "proto tcp mod comment comment \"user:" ^ uname ^ "\" {\n");
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218 TextIO.output (tcp_inf, concat lines);
219 TextIO.output (tcp_inf, "\n}\n\n")
220 end handle OS.SysErr _ => print "Invalid user in firewall config, skipping.\n" (* no sense in opening ports for bad users *)
1a03ee46 221
1933c596 222 fun writeUserOutRules tcp_outf (uname, lines) =
acef55cc 223 let
1a03ee46 224 val uid = SysWord.toInt (Posix.ProcEnv.uidToWord (Posix.SysDB.Passwd.uid (Posix.SysDB.getpwnam uname)))
acef55cc 225 in
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226 TextIO.output (tcp_outf, "mod owner uid-owner " ^ (Int.toString uid) ^ " mod comment comment \"user:" ^ uname ^ "\" proto tcp {\n");
227 TextIO.output (tcp_outf, concat lines);
228 TextIO.output (tcp_outf, "\nDROP;\n}\n\n")
1a03ee46 229 end handle OS.SysErr _ => print "Invalid user in firewall config, skipping.\n"
93278775 230
ec95f39f 231 in
1a03ee46 232 write_tcp_in_conf_preamble (users_tcp_in_conf);
1933c596 233 StringMap.appi (writeUserOutRules users_tcp_out_conf) (#output_rules nodeFermRules);
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234 StringMap.appi (writeUserInRules users_tcp_in_conf) (#input_rules nodeFermRules);
235
236 write_tcp_in_conf_preamble (users_tcp6_in_conf);
1933c596 237 StringMap.appi (writeUserOutRules users_tcp6_out_conf) (#output6_rules nodeFermRules);
93278775 238 StringMap.appi (writeUserInRules users_tcp6_in_conf) (#input6_rules nodeFermRules);
f9548f16 239
ec95f39f 240 TextIO.closeOut users_tcp_out_conf;
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241 TextIO.closeOut users_tcp_in_conf;
242
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243 TextIO.closeOut users_tcp6_out_conf;
244 TextIO.closeOut users_tcp6_in_conf;
245
73b95423 246 true
ec95f39f 247 end
73b95423 248
1933c596 249
93278775 250fun publishConfig _ =
73b95423 251 Slave.shell [Config.Firewall.reload]
f9548f16 252end