prosody
c633e1338554
util/uuid.lua

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util/uuid.lua @ 7057:c633e1338554

util.uuid: Use /dev/urandom
author Kim Alvefur <zash@zash.se>
date Wed, 06 Jan 2016 02:46:47 +0100
parent 7010:001b3cff4ed8
child 7061:eda0feeaf759
child 7076:ad9e683b8f0b
comparison
equal deleted inserted replaced
7056:7b0651e4534f 7057:c633e1338554
4 -- 4 --
5 -- This project is MIT/X11 licensed. Please see the 5 -- This project is MIT/X11 licensed. Please see the
6 -- COPYING file in the source package for more information. 6 -- COPYING file in the source package for more information.
7 -- 7 --
8 8
9 9 local error = error;
10 local tostring = tostring; 10 local round_up = math.ceil;
11 local os_time = os.time; 11 local urandom, urandom_err = io.open("/dev/urandom", "r+");
12 local os_clock = os.clock;
13 local sha1 = require "util.hashes".sha1;
14 12
15 module "uuid" 13 module "uuid"
16 14
17 local last_uniq_time = 0;
18 local function uniq_time()
19 local new_uniq_time = os_time();
20 if last_uniq_time >= new_uniq_time then new_uniq_time = last_uniq_time + 1; end
21 last_uniq_time = new_uniq_time;
22 return new_uniq_time;
23 end
24
25 local function new_random(x)
26 return sha1(x..os_clock()..tostring({}), true);
27 end
28
29 local buffer = new_random(uniq_time());
30 local function _seed(x)
31 buffer = new_random(buffer..x);
32 end
33 local function get_nibbles(n) 15 local function get_nibbles(n)
34 if #buffer < n then _seed(uniq_time()); end 16 local binary_random = urandom:read(round_up(n/2));
35 local r = buffer:sub(0, n); 17 local hex_random = binary_random:gsub(".",
36 buffer = buffer:sub(n+1); 18 function (x) return ("%02x"):format(x:byte()) end);
37 return r; 19 return hex_random:sub(1, n);
38 end 20 end
39 local function get_twobits() 21 local function get_twobits()
40 return ("%x"):format(get_nibbles(1):byte() % 4 + 8); 22 return ("%x"):format(urandom:read(1):byte() % 4 + 8);
41 end 23 end
42 24
43 function generate() 25 function generate()
26 if not urandom then
27 error("Unable to obtain a secure random number generator, please see https://prosody.im/doc/random ("..urandom_err..")");
28 end
44 -- generate RFC 4122 complaint UUIDs (version 4 - random) 29 -- generate RFC 4122 complaint UUIDs (version 4 - random)
45 return get_nibbles(8).."-"..get_nibbles(4).."-4"..get_nibbles(3).."-"..(get_twobits())..get_nibbles(3).."-"..get_nibbles(12); 30 return get_nibbles(8).."-"..get_nibbles(4).."-4"..get_nibbles(3).."-"..(get_twobits())..get_nibbles(3).."-"..get_nibbles(12);
46 end 31 end
47 seed = _seed; 32
33 function seed(x)
34 urandom:write(x);
35 urandom:flush();
36 end
48 37
49 return _M; 38 return _M;