Software / code / prosody
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tools/generate_format_spec.lua @ 12180:53e0ae770917
util.xml: Do not allow doctypes, comments or processing instructions
Yes. This is as bad as it sounds. CVE pending.
In Prosody itself, this only affects mod_websocket, which uses util.xml
to parse the <open/> frame, thus allowing unauthenticated remote DoS
using Billion Laughs. However, third-party modules using util.xml may
also be affected by this.
This commit installs handlers which disallow the use of doctype
declarations and processing instructions without any escape hatch. It,
by default, also introduces such a handler for comments, however, there
is a way to enable comments nontheless.
This is because util.xml is used to parse human-facing data, where
comments are generally a desirable feature, and also because comments
are generally harmless.
| author | Jonas Schäfer <jonas@wielicki.name> |
|---|---|
| date | Mon, 10 Jan 2022 18:23:54 +0100 |
| parent | 12039:e0a8c5b1ab4f |
| rev | line source |
|---|---|
| 12034 | 1 local format = require"util.format".format; |
|
12037
82f6a0b0a425
tools/generate_format_spec: Apply lua-format to silence luacheck
Kim Alvefur <zash@zash.se>
parents:
12034
diff
changeset
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2 local dump = require"util.serialization".new("oneline") |
| 12034 | 3 local types = { |
| 4 "nil"; | |
| 5 "boolean"; | |
| 6 "number"; | |
| 7 "string"; | |
| 8 "function"; | |
| 9 -- "userdata"; | |
| 10 "thread"; | |
| 11 "table"; | |
| 12 }; | |
| 13 local example_values = { | |
| 14 ["nil"] = { n = 1; nil }; | |
| 15 ["boolean"] = { true; false }; | |
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12037
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tools/generate_format_spec: Apply lua-format to silence luacheck
Kim Alvefur <zash@zash.se>
parents:
12034
diff
changeset
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16 ["number"] = { 97; -12345; 1.5; 73786976294838206464; math.huge; 2147483647 }; |
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82f6a0b0a425
tools/generate_format_spec: Apply lua-format to silence luacheck
Kim Alvefur <zash@zash.se>
parents:
12034
diff
changeset
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17 ["string"] = { "hello"; "foo \1\2\3 bar"; "nödåtgärd"; string.sub("nödåtgärd", 1, -4) }; |
| 12034 | 18 ["function"] = { function() end }; |
| 19 -- ["userdata"] = {}; | |
| 20 ["thread"] = { coroutine.create(function() end) }; | |
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12039
e0a8c5b1ab4f
util.format: Ensure metatable __tostring results are also sanitized
Kim Alvefur <zash@zash.se>
parents:
12037
diff
changeset
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21 ["table"] = { {}, setmetatable({},{__tostring=function ()return "foo \1\2\3 bar"end}) }; |
| 12034 | 22 }; |
| 23 local example_strings = setmetatable({ | |
| 24 ["nil"] = { "nil" }; | |
| 25 ["function"] = { "function() end" }; | |
|
12037
82f6a0b0a425
tools/generate_format_spec: Apply lua-format to silence luacheck
Kim Alvefur <zash@zash.se>
parents:
12034
diff
changeset
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26 ["number"] = { "97"; "-12345"; "1.5"; "73786976294838206464"; "math.huge"; "2147483647" }; |
| 12034 | 27 ["thread"] = { "coroutine.create(function() end)" }; |
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12039
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util.format: Ensure metatable __tostring results are also sanitized
Kim Alvefur <zash@zash.se>
parents:
12037
diff
changeset
|
28 ["table"] = { "{ }", "setmetatable({},{__tostring=function ()return \"foo \\1\\2\\3 bar\"end})" } |
| 12034 | 29 }, { __index = function() return {} end }); |
| 30 for _, lua_type in ipairs(types) do | |
| 31 print(string.format("\t\tdescribe(\"%s\", function ()", lua_type)); | |
| 32 local examples = example_values[lua_type]; | |
| 33 for fmt in ("cdiouxXaAeEfgGqs"):gmatch(".") do | |
| 34 print(string.format("\t\t\tdescribe(\"to %%%s\", function ()", fmt)); | |
| 35 print("\t\t\t\tit(\"works\", function ()"); | |
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tools/generate_format_spec: Apply lua-format to silence luacheck
Kim Alvefur <zash@zash.se>
parents:
12034
diff
changeset
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36 for i = 1, examples.n or #examples do |
| 12034 | 37 local example = examples[i]; |
| 38 if not tostring(example):match("%w+: 0[xX]%x+") then | |
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tools/generate_format_spec: Apply lua-format to silence luacheck
Kim Alvefur <zash@zash.se>
parents:
12034
diff
changeset
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39 print(string.format("\t\t\t\t\tassert.equal(%q, format(%q, %s))", format("%" .. fmt, example), "%" .. fmt, |
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tools/generate_format_spec: Apply lua-format to silence luacheck
Kim Alvefur <zash@zash.se>
parents:
12034
diff
changeset
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40 example_strings[lua_type][i] or dump(example))); |
| 12034 | 41 else |
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tools/generate_format_spec: Apply lua-format to silence luacheck
Kim Alvefur <zash@zash.se>
parents:
12034
diff
changeset
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42 print(string.format("\t\t\t\t\tassert.matches(\"[%s: 0[xX]%%x+]\", format(%q, %s))", lua_type, "%" .. fmt, |
|
82f6a0b0a425
tools/generate_format_spec: Apply lua-format to silence luacheck
Kim Alvefur <zash@zash.se>
parents:
12034
diff
changeset
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43 example_strings[lua_type][i] or dump(example))); |
| 12034 | 44 end |
| 45 end | |
| 46 print("\t\t\t\tend);"); | |
| 47 print("\t\t\tend);"); | |
| 48 print() | |
| 49 end | |
| 50 print("\t\tend);"); | |
| 51 print() | |
| 52 end |
