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replaced so that all NSE modules will have strict declared global checking at runtime. This should catch most developer errors early. Please see [1] for further reference into the problem. [1] http://seclists.org/nmap-dev/2009/q3/0070.html
84 lines
2.2 KiB
Lua
84 lines
2.2 KiB
Lua
--- Strict Declared Global library.
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--
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-- Checks for undeclared global variables during runtime execution. This module
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-- places the 'strict' function in the global environment. The strict function
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-- allows a script to add runtime checking so that undeclared globals cause
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-- an error to be raised. This is useful for finding accidental use of globals
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-- when local was intended.
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-- A global variable is considered 'declared' if the script makes an assignment
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-- to the global name (even nil).
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--
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-- @class module
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-- @name strict
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-- @copyright Copyright© Same as Nmap--See http://nmap.org/book/man-legal.html
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local error = error;
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local getfenv = getfenv;
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local lmodule = module;
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local rawset = rawset;
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local rawget = rawget;
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local setfenv = setfenv;
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local type = type;
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local getinfo = debug.getinfo;
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local function what ()
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local d = getinfo(3, "S");
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return d and d.what or "C";
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end
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--- The strict function.
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--
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-- This function adds runtime checking to the global environment for use of
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-- undeclared globals. A global is 'undeclared' if not assigned in the file
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-- (script) scope previously. An error will be raised on use of an undeclared
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-- global.
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function strict ()
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local _G = getfenv(2);
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local mt = getmetatable(_G) or setmetatable(_G, {}) and getmetatable(_G);
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local _newindex, _index = mt.__newindex, mt.__index;
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mt.__declared = {};
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function mt.__newindex (t, n, v)
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if type(_newindex) == "function" then
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_newindex(t, n, v); -- hook it
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end
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if not mt.__declared[n] then
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local w = what();
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if w ~= "main" and w ~= "C" then
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error("assign to undeclared variable '"..n.."'", 2);
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end
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mt.__declared[n] = true;
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end
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rawset(t, n, v);
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end
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function mt.__index (t, n)
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if type(_index) == "function" then
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local v = _index(t, n); -- hook it
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if v ~= nil then return v end
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else
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local v = _index[n];
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if v ~= nil then return v end
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end
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if not mt.__declared[n] and what() ~= "C" then
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error("variable '"..n.."' is not declared", 2);
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end
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return rawget(t, n);
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end
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end
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local strict = strict;
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function module (...)
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local myenv = getfenv(1);
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lmodule(...);
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strict();
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setfenv(2, getfenv(1));
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setfenv(1, myenv);
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end
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return strict;
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