Assuming the above is correct, the only question is whether the below will work as it should (the changes to the seed function and the 2 new function - get_rand_bytes
and random_string
):
-- vim:set ts=4 sts=4 sw=4 et:
--- jit-uuid
-- Fast and dependency-free UUID library for LuaJIT/ngx_lua.
-- @module jit-uuid
-- @author Thibault Charbonnier
-- @license MIT
-- @release 0.0.7
local bit = require 'bit'
local tohex = bit.tohex
local band = bit.band
local bor = bit.bor
local _M = {
_VERSION = '0.0.7'
}
----------
-- seeding
----------
-- try to get n_bytes of CSPRNG data, first via /dev/urandom,
-- and then falling back to OpenSSL if necessary
function _M.get_rand_bytes(n_bytes, urandom)
local buf = ffi_new(bytes_buf_t, n_bytes)
ffi_fill(buf, n_bytes, 0x0)
-- only read from urandom if we were explicitly asked
if urandom then
local rc = urandom_bytes(buf, n_bytes)
-- if the read of urandom was successful, we returned true
-- and buf is filled with our bytes, so return it as a string
if rc then
return ffi_str(buf, n_bytes)
end
end
if C.RAND_bytes(buf, n_bytes) == 0 then
-- get error code
local err_code = C.ERR_get_error()
if err_code == 0 then
return nil, "could not get SSL error code from the queue"
end
-- get human-readable error string
C.ERR_load_crypto_strings()
local err = C.ERR_reason_error_string(err_code)
C.ERR_free_strings()
return nil, "could not get random bytes (" ..
"reason:" .. ffi_str(err) .. ") "
end
return ffi_str(buf, n_bytes)
end
do
local char = string.char
local rand = math.random
local encode_base64 = ngx.encode_base64
-- generate a random-looking string by retrieving a chunk of bytes and
-- replacing non-alphanumeric characters with random alphanumeric replacements
-- (we dont care about deriving these bytes securely)
-- this serves to attempt to maintain some backward compatibility with the
-- previous implementation (stripping a UUID of its hyphens), while significantly
-- expanding the size of the keyspace.
local function random_string()
-- get 24 bytes, which will return a 32 char string after encoding
-- this is done in attempt to maintain backwards compatibility as
-- much as possible while improving the strength of this function
return encode_base64(get_rand_bytes(24, true))
:gsub("/", char(rand(48, 57))) -- 0 - 10
:gsub("+", char(rand(65, 90))) -- A - Z
:gsub("=", char(rand(97, 122))) -- a - z
end
_M.random_string = random_string
end
--- Seed the random number generator.
-- Under the hood, this function calls `math.randomseed`.
-- It makes sure to use the most appropriate seeding technique for
-- the current environment, guaranteeing a unique seed.
--
-- To guarantee unique UUIDs, you must have correctly seeded
-- the Lua pseudo-random generator (with `math.randomseed`).
-- You are free to seed it any way you want, but this function
-- can do it for you if you'd like, with some added guarantees.
--
-- @param[type=number] seed (Optional) A seed to use. If none given, will
-- generate one trying to use the most appropriate technique.
-- @treturn number `seed`: the seed given to `math.randomseed`.
-- @usage
-- local uuid = require 'resty.jit-uuid'
-- uuid.seed()
--
-- -- in ngx_lua, seed in the init_worker context:
-- init_worker_by_lua {
-- local uuid = require 'resty.jit-uuid'
-- uuid.seed()
-- }
function _M.seed(seed)
if not seed then
if ngx then
if ngx.worker.pid() == 1 then
seed = _M.random_string()
else
seed = ngx.time() + ngx.worker.pid()
end
elseif package.loaded['socket'] and package.loaded['socket'].gettime then
seed = package.loaded['socket'].gettime()*10000
else
seed = os.time()
end
end
math.randomseed(seed)
return seed
end
-------------
-- validation
-------------
do
if ngx and string.find(ngx.config.nginx_configure(),'--with-pcre-jit',nil,true) then
local type = type
local re_find = ngx.re.find
local regex = '^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$'
--- Validate a string as a UUID.
-- To be considered valid, a UUID must be given in its canonical
-- form (hexadecimal digits including the hyphen characters).
-- This function validates UUIDs disregarding their generation algorithm,
-- and in a case-insensitive manner, but checks the variant field.
--
-- Use JIT PCRE if available in OpenResty or fallbacks on Lua patterns.
--
-- @param[type=string] str String to verify.
-- @treturn boolean `valid`: true if valid UUID, false otherwise.
-- @usage
-- local uuid = require 'resty.jit-uuid'
--
-- uuid.is_valid 'cbb297c0-a956-486d-ad1d-f9bZZZZZZZZZ' --> false
-- uuid.is_valid 'cbb297c0-a956-486d-dd1d-f9b42df9465a' --> false (invalid variant)
-- uuid.is_valid 'cbb297c0a956486dad1df9b42df9465a' --> false (no dashes)
-- uuid.is_valid 'cbb297c0-a956-486d-ad1d-f9b42df9465a' --> true
function _M.is_valid(str)
-- it has proven itself efficient to first check the length with an
-- evenly distributed set of valid and invalid uuid lengths.
if type(str) ~= 'string' or #str ~= 36 then
return false
end
return re_find(str, regex, 'ioj') ~= nil
end
else
local match = string.match
local d = '[0-9a-fA-F]'
local p = '^' .. table.concat({
d:rep(8),
d:rep(4),
d:rep(4),
'[89ab]' .. d:rep(3),
d:rep(12)
}, '%-') .. '$'
function _M.is_valid(str)
if type(str) ~= 'string' or #str ~= 36 then
return false
end
return match(str, p) ~= nil
end
end
end
----------------
-- v4 generation
----------------
do
local fmt = string.format
local random = math.random
--- Generate a v4 UUID.
-- v4 UUIDs are created from randomly generated numbers.
--
-- @treturn string `uuid`: a v4 (randomly generated) UUID.
-- @usage
-- local uuid = require 'resty.jit-uuid'
--
-- local u1 = uuid() ---> __call metamethod
-- local u2 = uuid.generate_v4()
function _M.generate_v4()
return (fmt('%s%s%s%s-%s%s-%s%s-%s%s-%s%s%s%s%s%s',
tohex(random(0, 255), 2),
tohex(random(0, 255), 2),
tohex(random(0, 255), 2),
tohex(random(0, 255), 2),
tohex(random(0, 255), 2),
tohex(random(0, 255), 2),
tohex(bor(band(random(0, 255), 0x0F), 0x40), 2),
tohex(random(0, 255), 2),
tohex(bor(band(random(0, 255), 0x3F), 0x80), 2),
tohex(random(0, 255), 2),
tohex(random(0, 255), 2),
tohex(random(0, 255), 2),
tohex(random(0, 255), 2),
tohex(random(0, 255), 2),
tohex(random(0, 255), 2),
tohex(random(0, 255), 2)))
end
end
----------------
-- v3/v5 generation
----------------
do
if ngx then
local ffi = require 'ffi'
local tonumber = tonumber
local assert = assert
local error = error
local concat = table.concat
local type = type
local char = string.char
local fmt = string.format
local sub = string.sub
local gmatch = ngx.re.gmatch
local sha1_bin = ngx.sha1_bin
local md5 = ngx.md5
local C = ffi.C
local ffi_new = ffi.new
local ffi_str = ffi.string
local ffi_cast = ffi.cast
local new_tab
do
local ok
ok, new_tab = pcall(require, 'table.new')
if not ok then
new_tab = function(narr, nrec) return {} end
end
end
ffi.cdef [[
typedef unsigned char u_char;
typedef intptr_t ngx_int_t;
u_char * ngx_hex_dump(u_char *dst, const u_char *src, size_t len);
ngx_int_t ngx_hextoi(u_char *line, size_t n);
]]
local str_type = ffi.typeof('uint8_t[?]')
local u_char_type = ffi.typeof('u_char *')
local function bin_tohex(s)
local slen = #s
local blen = slen * 2
local buf = ffi_new(str_type, blen)
C.ngx_hex_dump(buf, s, slen)
return ffi_str(buf, blen)
end
local function hex_to_i(s)
local buf = ffi_cast(u_char_type, s)
local n = tonumber(C.ngx_hextoi(buf, #s))
if n == -1 then
error("could not convert hex to number")
end
return n
end
local buf = new_tab(16, 0)
local function factory(namespace, hash_fn)
if not _M.is_valid(namespace) then
return nil, 'namespace must be a valid UUID'
end
local i = 0
local iter, err = gmatch(namespace, [[([\da-f][\da-f])]])
if not iter then
return nil, 'could not create iter: ' .. err
end
while true do
local m, err = iter()
if err then
return nil, err
end
if not m then
break
end
i = i + 1
buf[i] = char(tonumber(m[0], 16))
end
assert(i == 16, "invalid binary namespace buffer length")
local ns = concat(buf)
return function(name)
if type(name) ~= 'string' then
return nil, 'name must be a string'
end
local hash, ver, var = hash_fn(ns, name)
return (fmt('%s-%s-%s%s-%s%s-%s', sub(hash, 1, 8),
sub(hash, 9, 12),
ver,
sub(hash, 15, 16),
var,
sub(hash, 19, 20),
sub(hash, 21, 32)))
end
end
local function v3_hash(binary, name)
local hash = md5(binary .. name)
return hash,
tohex(bor(band(hex_to_i(sub(hash, 13, 14)), 0x0F), 0x30), 2),
tohex(bor(band(hex_to_i(sub(hash, 17, 18)), 0x3F), 0x80), 2)
end
local function v5_hash(binary, name)
local hash = bin_tohex(sha1_bin(binary .. name))
return hash,
tohex(bor(band(hex_to_i(sub(hash, 13, 14)), 0x0F), 0x50), 2),
tohex(bor(band(hex_to_i(sub(hash, 17, 18)), 0x3F), 0x80), 2)
end
--- Instanciate a v3 UUID factory.
-- @function factory_v3
-- Creates a closure generating namespaced v3 UUIDs.
-- @param[type=string] namespace (must be a valid UUID according to `is_valid`)
-- @treturn function `factory`: a v3 UUID generator.
-- @treturn string `err`: a string describing an error
-- @usage
-- local uuid = require 'resty.jit-uuid'
--
-- local fact = assert(uuid.factory_v3('e6ebd542-06ae-11e6-8e82-bba81706b27d'))
--
-- local u1 = fact('hello')
-- ---> 3db7a435-8c56-359d-a563-1b69e6802c78
--
-- local u2 = fact('foobar')
-- ---> e8d3eeba-7723-3b72-bbc5-8f598afa6773
function _M.factory_v3(namespace)
return factory(namespace, v3_hash)
end
--- Instanciate a v5 UUID factory.
-- @function factory_v5
-- Creates a closure generating namespaced v5 UUIDs.
-- @param[type=string] namespace (must be a valid UUID according to `is_valid`)
-- @treturn function `factory`: a v5 UUID generator.
-- @treturn string `err`: a string describing an error
-- @usage
-- local uuid = require 'resty.jit-uuid'
--
-- local fact = assert(uuid.factory_v5('e6ebd542-06ae-11e6-8e82-bba81706b27d'))
--
-- local u1 = fact('hello')
-- ---> 4850816f-1658-5890-8bfd-1ed14251f1f0
--
-- local u2 = fact('foobar')
-- ---> c9be99fc-326b-5066-bdba-dcd31a6d01ab
function _M.factory_v5(namespace)
return factory(namespace, v5_hash)
end
--- Generate a v3 UUID.
-- v3 UUIDs are created from a namespace and a name (a UUID and a string).
-- The same name and namespace result in the same UUID. The same name and
-- different namespaces result in different UUIDs, and vice-versa.
-- The resulting UUID is derived using MD5 hashing.
--
-- This is a sugar function which instanciates a short-lived v3 UUID factory.
-- It is an expensive operation, and intensive generation using the same
-- namespaces should prefer allocating their own long-lived factory with
-- `factory_v3`.
--
-- @param[type=string] namespace (must be a valid UUID according to `is_valid`)
-- @param[type=string] name
-- @treturn string `uuid`: a v3 (namespaced) UUID.
-- @treturn string `err`: a string describing an error
-- @usage
-- local uuid = require 'resty.jit-uuid'
--
-- local u = uuid.generate_v3('e6ebd542-06ae-11e6-8e82-bba81706b27d', 'hello')
-- ---> 3db7a435-8c56-359d-a563-1b69e6802c78
function _M.generate_v3(namespace, name)
local fact, err = _M.factory_v3(namespace)
if not fact then
return nil, err
end
return fact(name)
end
--- Generate a v5 UUID.
-- v5 UUIDs are created from a namespace and a name (a UUID and a string).
-- The same name and namespace result in the same UUID. The same name and
-- different namespaces result in different UUIDs, and vice-versa.
-- The resulting UUID is derived using SHA-1 hashing.
--
-- This is a sugar function which instanciates a short-lived v5 UUID factory.
-- It is an expensive operation, and intensive generation using the same
-- namespaces should prefer allocating their own long-lived factory with
-- `factory_v5`.
--
-- @param[type=string] namespace (must be a valid UUID according to `is_valid`)
-- @param[type=string] name
-- @treturn string `uuid`: a v5 (namespaced) UUID.
-- @treturn string `err`: a string describing an error
-- @usage
-- local uuid = require 'resty.jit-uuid'
--
-- local u = uuid.generate_v5('e6ebd542-06ae-11e6-8e82-bba81706b27d', 'hello')
-- ---> 4850816f-1658-5890-8bfd-1ed14251f1f0
function _M.generate_v5(namespace, name)
local fact, err = _M.factory_v5(namespace)
if not fact then
return nil, err
end
return fact(name)
end
else
function _M.factory_v3() error('v3 UUID generation only supported in ngx_lua', 2) end
function _M.generate_v3() error('v3 UUID generation only supported in ngx_lua', 2) end
function _M.factory_v5() error('v5 UUID generation only supported in ngx_lua', 2) end
function _M.generate_v5() error('v5 UUID generation only supported in ngx_lua', 2) end
end
end
return setmetatable(_M, {
__call = _M.generate_v4
})
Thank you.