memory leak using cipher:

[bfg]

The following code leaks memory really badly (2G per in 7 seconds)

require "openssl"

secret_key = "secret"
cipher = openssl.get_cipher("RC4")

num = 10000000
i = 1
while i <= num do
        i = i+1

        id = "something"

        encrypted = cipher:encrypt(id, secret_key);
end

Lua environment:

$ uname -a
Linux pipi.dev.interseek.com 3.2.0-8-generic #14-Ubuntu SMP Fri Jan 6 01:56:48 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux

$ lua -v
Lua 5.1.4  Copyright (C) 1994-2008 Lua.org, PUC-Rio

$ luajit-2.0.0-beta9 -v
LuaJIT 2.0.0-beta9 -- Copyright (C) 2005-2011 Mike Pall. http://luajit.org/

$ openssl version
OpenSSL 1.0.0g 18 Jan 2012

Latest lua-openssl master

[zhaozg]

thanks, I will fix it in some days.

[zhaozg]

cipher encrypt/decrypt use EVP_CIPHER_CTX in stack, not in heap, it should be call EVP_CIPHER_CTX_cleanup to free ctx memory.
Please fetch head to fix it.

Thanks!

[bfg]

Great work man! Process now consistently uses 1.9M of RAM!

Thanks ALOT :)

[zhaozg]

:).

Here a advice, if you want to encrypt some important information, such like a password, you should add salt,to get diff cipher text by same plain password.

1. get a cihper
2. get md5 digest
3. generate 8 length salt
4. make key and iv will your salt and password.
5. encrypt data with key and Iv
6. concat magic, salt and encrypted data
7. base64 encode it

local openssl = require'openssl'
require 'base64'

c = openssl.get_cipher('bf')
md = openssl.get_digest('md5')

salt = openssl.random_bytes(8, true) -- generate salt
m = '"abcd"'
key, iv = c:BytesToKey(md,salt,'aa')
cc=c:init(true,key,iv)
e1 = cc:update(m)
bb = e1..cc:final()
print(base64.encode('Salted__'..salt..bb))

---

local openssl = require'openssl'
--base64 is a other lib, please see http://lua-users.org/wiki/BaseSixtyFour
require 'base64'

c = openssl.get_cipher('bf')
md = openssl.get_digest('md5')

--openssl.random_bytes(number length [, boolean strong=false])
---> string, boolean
--Returns a string of the length specified filled with random bytes

salt = openssl.random_bytes(8, true)
m = '"abcd"'
key, iv = c:BytesToKey(md,salt,'aa')

---evp_cipher:init(bool enc, [, string key [,string iv [,engine engimp]]]) => cipher_ctx
---evp_cipher:encrypt_init has renamed to evp_cipher:init
--true means to do encrypt

cc=c:init(true,key,iv)
e1 = cc:update(m)
bb = e1..cc:final()
print(base64.encode('Salted__'..salt..bb))