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util/format.lua @ 12943:297b4cfcc3d9
util.jsonschema: Ignore some new tests in test suite
These seem to be using absolute URI references, Not Yet Implemented
author | Kim Alvefur <zash@zash.se> |
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date | Sat, 11 Mar 2023 12:01:17 +0100 |
parent | 12781:22066b02887f |
child | 12975:d10957394a3c |
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-- -- A string.format wrapper that gracefully handles invalid arguments since -- certain format string and argument combinations may cause errors or other -- issues like log spoofing -- -- Provides some protection from e.g. CAPEC-135, CWE-117, CWE-134, CWE-93 local tostring = tostring; local unpack = table.unpack; local pack = table.pack; local valid_utf8 = require "util.encodings".utf8.valid; local type = type; local dump = require "util.serialization".new("debug"); local num_type = math.type; -- In Lua 5.3+ these formats throw an error if given a float local expects_integer = { c = true, d = true, i = true, o = true, u = true, X = true, x = true, }; -- In Lua 5.2 these throw an error given a negative number local expects_positive = { o = true; u = true; x = true; X = true }; -- Printable Unicode replacements for control characters local control_symbols = { -- 0x00 .. 0x1F --> U+2400 .. U+241F, 0x7F --> U+2421 ["\000"] = "\226\144\128", ["\001"] = "\226\144\129", ["\002"] = "\226\144\130", ["\003"] = "\226\144\131", ["\004"] = "\226\144\132", ["\005"] = "\226\144\133", ["\006"] = "\226\144\134", ["\007"] = "\226\144\135", ["\008"] = "\226\144\136", ["\009"] = "\226\144\137", ["\010"] = "\226\144\138", ["\011"] = "\226\144\139", ["\012"] = "\226\144\140", ["\013"] = "\226\144\141", ["\014"] = "\226\144\142", ["\015"] = "\226\144\143", ["\016"] = "\226\144\144", ["\017"] = "\226\144\145", ["\018"] = "\226\144\146", ["\019"] = "\226\144\147", ["\020"] = "\226\144\148", ["\021"] = "\226\144\149", ["\022"] = "\226\144\150", ["\023"] = "\226\144\151", ["\024"] = "\226\144\152", ["\025"] = "\226\144\153", ["\026"] = "\226\144\154", ["\027"] = "\226\144\155", ["\028"] = "\226\144\156", ["\029"] = "\226\144\157", ["\030"] = "\226\144\158", ["\031"] = "\226\144\159", ["\127"] = "\226\144\161", }; local supports_p = pcall(string.format, "%p", ""); -- >= Lua 5.4 local function format(formatstring, ...) local args = pack(...); local args_length = args.n; -- format specifier spec: -- 1. Start: '%%' -- 2. Flags: '[%-%+ #0]' -- 3. Width: '%d?%d?' -- 4. Precision: '%.?%d?%d?' -- 5. Option: '[cdiouxXaAeEfgGqs%%]' -- -- The options c, d, E, e, f, g, G, i, o, u, X, and x all expect a number as argument, whereas q and s expect a string. -- This function does not accept string values containing embedded zeros, except as arguments to the q option. -- a and A are only in Lua 5.2+ -- Lua 5.4 adds a p format that produces a pointer -- process each format specifier local i = 0; formatstring = formatstring:gsub("%%[^cdiouxXaAeEfgGpqs%%]*[cdiouxXaAeEfgGpqs%%]", function(spec) if spec == "%%" then return end i = i + 1; local arg = args[i]; if arg == nil then args[i] = "nil"; return "(%s)"; end local option = spec:sub(-1); local t = type(arg); if option == "s" and t == "string" and not arg:find("[%z\1-\31\128-\255]") then -- No UTF-8 or control characters, assumed to be the common case. return elseif t == "number" then if option == "g" or (option == "d" and num_type(arg) == "integer") then return end elseif option == "s" and t ~= "string" then arg = tostring(arg); t = "string"; end if option ~= "s" and option ~= "q" and option ~= "p" then -- all other options expect numbers if t ~= "number" then -- arg isn't number as expected? arg = tostring(arg); option = "s"; spec = "[%s]"; t = "string"; elseif expects_integer[option] and num_type(arg) ~= "integer" then args[i] = tostring(arg); return "[%s]"; elseif expects_positive[option] and arg < 0 then args[i] = tostring(arg); return "[%s]"; else return -- acceptable number end end if option == "p" and not supports_p then arg = tostring(arg); option = "s"; spec = "[%s]"; t = "string"; end if t == "string" and option ~= "p" then if not valid_utf8(arg) then option = "q"; elseif option ~= "q" then -- gets fully escaped in the next block -- Prevent funny things with ASCII control characters and ANSI escape codes (CWE-117) -- Also ensure embedded newlines can't look like another log line (CWE-93) args[i] = arg:gsub("[%z\1-\8\11-\31\127]", control_symbols):gsub("\n\t?", "\n\t"); return spec; end end if option == "q" then args[i] = dump(arg); return "%s"; end if option == "p" and (t == "boolean" or t == "number") then args[i] = tostring(arg); return "[%s]"; end end); -- process extra args while i < args_length do i = i + 1; local arg = args[i]; if arg == nil then args[i] = "(nil)"; else args[i] = tostring(arg):gsub("[%z\1-\8\11-\31\127]", control_symbols):gsub("\n\t?", "\n\t"); end formatstring = formatstring .. " [%s]" end return formatstring:format(unpack(args)); end return { format = format; };