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Economy => Services => Topic started by: theymos on June 03, 2012, 06:01:26 AM


Title: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: theymos on June 03, 2012, 06:01:26 AM
The forum will pay 40 BTC for a patch to SMF version 1.1.16 upgrading password hash security.

You should use these PHP functions I've written for doing the actual hashing:

Code:
//salted SHA-256 with 7500 rounds
define('CRYPT_PARAMS', '$5$rounds=7500$');

//get $bytes bytes of secure random binary data
function urandom($bytes)
{
	$file = fopen('/dev/urandom', 'rb');
	$result = fread($file, $bytes);
	fclose($file);
	if(strlen($result) < $bytes)
		die('urandom byte length mismatch');
	return $result;
}

//hash and salt a new password for insertion into the database
function newpass($pass)
{ 
	return crypt($pass, CRYPT_PARAMS . base64_encode(urandom(12)) . '$');
}

//compare a provided password with the hash in the database
function password_is_valid($entered_password, $db_hash)
{
	return crypt($entered_password, $db_hash) === $db_hash;
}

//old password comparison:
//sha1(strtolower($user) . $entered_password) == $db_hash
//new password comparison:
//password_is_valid($entered_password, $db_hash)

You need to do this:
- In LogInOut.php, upgrade SMF SHA-1 hashes to these new hashes automatically. Also, update any passwords that pass password_is_valid() but have a different CRYPT_PARAMS prefix than is being used currently.
- Change all old password comparisons to the new method.
- Wherever passwords are updated, use newpass() instead of SMF's method.
- Thoroughly test all aspects of this modification. I am mostly paying someone to do this change instead of doing it myself because bugs in this would create a huge mess and I therefore want someone more experienced in software testing to do it.

Hint: SMF has a "salt" column in the database and a "passwordSalt" variable, but these aren't actually used for password hashing. You only need to deal with the "passwd" column/variable.

PM me or post here if you're interested. I will pick the best candidate in a week or two. You should only apply if you're already pretty well-trusted in the community.

(Do not post in this thread about how you prefer another hashing method.)

Title: Re: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: M4v3R on June 07, 2012, 11:42:34 AM
I have some experience with SMF v1.1 mods, and I run a Bitcoin exchange (built with PHP) which already uses proper password security. So I can provide the extension you need.

Title: Re: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: publio on June 07, 2012, 08:01:45 PM
If you're creating salts, you may want to use a CSPRNG.  So, you want /dev/random instead of urandom.

Title: Re: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: theymos on June 07, 2012, 08:24:42 PM
Quote from: publio on June 07, 2012, 08:01:45 PM
If you're creating salts, you may want to use a CSPRNG.  So, you want /dev/random instead of urandom.

/dev/urandom is more than sufficient. It's not very important for the salt to be unpredictable.

Title: Re: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: publio on June 08, 2012, 12:08:47 AM
It's considered best practice to use CSPRNGs for any cryptography, including salts.  Predictable salts may offer protection against rainbow tables..  Maybe it protects against "theoretical attacks"?

Take a look at this page:
http://books.google.com/books?id=QJNoykS0Tv4C&lpg=PT199&ots=JN9mj5AsnT&dq=salt+csprng&pg=PT199&redir_esc=y#v=onepage&q&f=false (http://books.google.com/books?id=QJNoykS0Tv4C&lpg=PT199&ots=JN9mj5AsnT&dq=salt+csprng&pg=PT199&redir_esc=y#v=onepage&q&f=false)

It turns out that urandom is also cryptographically secure. :D The php function, mt_rand(), for example, is not.

Title: Re: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: live627 on June 12, 2012, 08:51:36 PM
Do you want a direct file edit or a modification format that the package manager can use? I'm comfortable with both; however, the latter could be a no-go for you for obvious security reasons.

Title: Re: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: AndyRossy on June 13, 2012, 12:33:40 AM
has the candidate for this been chosen yet theymos?

Title: Re: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: theymos on June 13, 2012, 01:02:32 AM
Quote from: AndyRossy on June 13, 2012, 12:33:40 AM
has the candidate for this been chosen yet theymos?

No.

Quote from: live627 on June 12, 2012, 08:51:36 PM
Do you want a direct file edit or a modification format that the package manager can use? I'm comfortable with both; however, the latter could be a no-go for you for obvious security reasons.

Either is fine. I was thinking a non-modification patch, since that seems much easier to write.

Title: Re: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: live627 on June 13, 2012, 03:37:09 AM
I'm willing to do this.

Title: Re: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: error on June 16, 2012, 03:09:26 PM
Just saw this post. I've taken a quick look and I believe I can do this as an SMF mod. Among my other qualifications I help run another SMF forum (http://bbs.freetalklive.com/profile/?u=1551) you may have heard of.

Title: Re: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: theymos on June 18, 2012, 04:10:40 AM
I've offered the job to error.

Thanks to all applicants for your interest!

Title: Re: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: error on July 11, 2012, 12:42:39 AM
This probably doesn't even need to be said, but theymos paid on time and in full. Not to mention it was a pleasure to work with him on this little project. I'm happy, and I am standing by in case there are any unforeseen issues.

Title: Re: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: theymos on July 11, 2012, 12:53:27 AM
Quote from: error on July 11, 2012, 12:42:39 AM
This probably doesn't even need to be said, but theymos paid on time and in full. Not to mention it was a pleasure to work with him on this little project. I'm happy, and I am standing by in case there are any unforeseen issues.

Thank you for your nice work on this.

Title: Re: SMF modification needed -- upgrade password hash security -- 40 BTC
Post by: Maged on July 11, 2012, 07:31:42 AM
Fantastic job on this, both of you!


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