prosody-modules
3092ae96c1f0
mod_compression_unsafe/mod_compression_unsafe.lua

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mod_compression_unsafe/mod_compression_unsafe.lua @ 2776:3092ae96c1f0

mod_compression: Rename to mod_compression_unsafe and add security note
author Matthew Wild <mwild1@gmail.com>
date Tue, 26 Sep 2017 14:08:39 +0100
parent 2482:mod_compression/mod_compression.lua@c96a53b0b820
child 2794:d42e9da671fd
comparison
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2775:8407137c0a3b 2776:3092ae96c1f0
1 -- Prosody IM
2 -- Copyright (C) 2009-2012 Tobias Markmann
3 --
4 -- This project is MIT/X11 licensed. Please see the
5 -- COPYING file in the source package for more information.
6 --
7
8 local st = require "util.stanza";
9 local zlib = require "zlib";
10 local pcall = pcall;
11 local tostring = tostring;
12
13 local xmlns_compression_feature = "http://jabber.org/features/compress"
14 local xmlns_compression_protocol = "http://jabber.org/protocol/compress"
15 local xmlns_stream = "http://etherx.jabber.org/streams";
16 local compression_stream_feature = st.stanza("compression", {xmlns=xmlns_compression_feature}):tag("method"):text("zlib"):up();
17 local add_filter = require "util.filters".add_filter;
18
19 local compression_level = module:get_option_number("compression_level", 7);
20
21 if not compression_level or compression_level < 1 or compression_level > 9 then
22 module:log("warn", "Invalid compression level in config: %s", tostring(compression_level));
23 module:log("warn", "Module loading aborted. Compression won't be available.");
24 return;
25 end
26
27 module:hook("stream-features", function(event)
28 local origin, features = event.origin, event.features;
29 if not origin.compressed and origin.type == "c2s" then
30 features:add_child(compression_stream_feature);
31 end
32 end);
33
34 module:hook("s2s-stream-features", function(event)
35 local origin, features = event.origin, event.features;
36 if not origin.compressed and origin.type == "s2sin" then
37 features:add_child(compression_stream_feature);
38 end
39 end);
40
41 -- Hook to activate compression if remote server supports it.
42 module:hook_stanza(xmlns_stream, "features",
43 function (session, stanza)
44 if not session.compressed and session.type == "s2sout" then
45 -- does remote server support compression?
46 local comp_st = stanza:get_child("compression", xmlns_compression_feature);
47 if comp_st then
48 -- do we support the mechanism
49 for a in comp_st:childtags("method") do
50 local algorithm = a:get_text();
51 if algorithm == "zlib" then
52 session.sends2s(st.stanza("compress", {xmlns=xmlns_compression_protocol}):tag("method"):text("zlib"))
53 session.log("debug", "Enabled compression using zlib.")
54 return true;
55 end
56 end
57 session.log("debug", "Remote server supports no compression algorithm we support.")
58 end
59 end
60 end
61 , 250);
62
63
64 -- returns either nil or a fully functional ready to use inflate stream
65 local function get_deflate_stream(session)
66 local status, deflate_stream = pcall(zlib.deflate, compression_level);
67 if status == false then
68 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
69 (session.sends2s or session.send)(error_st);
70 session.log("error", "Failed to create zlib.deflate filter.");
71 module:log("error", "%s", tostring(deflate_stream));
72 return
73 end
74 return deflate_stream
75 end
76
77 -- returns either nil or a fully functional ready to use inflate stream
78 local function get_inflate_stream(session)
79 local status, inflate_stream = pcall(zlib.inflate);
80 if status == false then
81 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
82 (session.sends2s or session.send)(error_st);
83 session.log("error", "Failed to create zlib.inflate filter.");
84 module:log("error", "%s", tostring(inflate_stream));
85 return
86 end
87 return inflate_stream
88 end
89
90 -- setup compression for a stream
91 local function setup_compression(session, deflate_stream)
92 add_filter(session, "bytes/out", function(t)
93 local status, compressed, eof = pcall(deflate_stream, tostring(t), 'sync');
94 if status == false then
95 module:log("warn", "%s", tostring(compressed));
96 session:close({
97 condition = "undefined-condition";
98 text = compressed;
99 extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
100 });
101 return;
102 end
103 return compressed;
104 end);
105 end
106
107 -- setup decompression for a stream
108 local function setup_decompression(session, inflate_stream)
109 add_filter(session, "bytes/in", function(data)
110 local status, decompressed, eof = pcall(inflate_stream, data);
111 if status == false then
112 module:log("warn", "%s", tostring(decompressed));
113 session:close({
114 condition = "undefined-condition";
115 text = decompressed;
116 extra = st.stanza("failure", {xmlns="http://jabber.org/protocol/compress"}):tag("processing-failed");
117 });
118 return;
119 end
120 return decompressed;
121 end);
122 end
123
124 module:hook("stanza/http://jabber.org/protocol/compress:compressed", function(event)
125 local session = event.origin;
126
127 if session.type == "s2sout" then
128 session.log("debug", "Activating compression...")
129 -- create deflate and inflate streams
130 local deflate_stream = get_deflate_stream(session);
131 if not deflate_stream then return true; end
132
133 local inflate_stream = get_inflate_stream(session);
134 if not inflate_stream then return true; end
135
136 -- setup compression for session.w
137 setup_compression(session, deflate_stream);
138
139 -- setup decompression for session.data
140 setup_decompression(session, inflate_stream);
141 session:reset_stream();
142 session:open_stream(session.from_host, session.to_host);
143 session.compressed = true;
144 return true;
145 end
146 end);
147
148 module:hook("stanza/http://jabber.org/protocol/compress:failure", function(event)
149 local err = event.stanza:get_child();
150 (event.origin.log or module._log)("warn", "Compression setup failed (%s)", err and err.name or "unknown reason");
151 return true;
152 end);
153
154 module:hook("stanza/http://jabber.org/protocol/compress:compress", function(event)
155 local session, stanza = event.origin, event.stanza;
156
157 if session.type == "c2s" or session.type == "s2sin" then
158 -- fail if we are already compressed
159 if session.compressed then
160 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed");
161 (session.sends2s or session.send)(error_st);
162 session.log("debug", "Client tried to establish another compression layer.");
163 return true;
164 end
165
166 -- checking if the compression method is supported
167 local method = stanza:get_child_text("method");
168 if method == "zlib" then
169 session.log("debug", "zlib compression enabled.");
170
171 -- create deflate and inflate streams
172 local deflate_stream = get_deflate_stream(session);
173 if not deflate_stream then return true; end
174
175 local inflate_stream = get_inflate_stream(session);
176 if not inflate_stream then return true; end
177
178 (session.sends2s or session.send)(st.stanza("compressed", {xmlns=xmlns_compression_protocol}));
179 session:reset_stream();
180
181 -- setup compression for session.w
182 setup_compression(session, deflate_stream);
183
184 -- setup decompression for session.data
185 setup_decompression(session, inflate_stream);
186
187 session.compressed = true;
188 elseif method then
189 session.log("debug", "%s compression selected, but we don't support it.", tostring(method));
190 local error_st = st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("unsupported-method");
191 (session.sends2s or session.send)(error_st);
192 else
193 (session.sends2s or session.send)(st.stanza("failure", {xmlns=xmlns_compression_protocol}):tag("setup-failed"));
194 end
195 return true;
196 end
197 end);
198