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Simple Machines Blogs => Developers' Blog => Topic started by: Sesquipedalian on December 28, 2019, 03:31:53 AM

Title: SMF 2.0.16+ cookie changes
Post by: Sesquipedalian on December 28, 2019, 03:31:53 AM
Hello all!

With SMF 2.0.16 we have introduced an important security change for our cookies. This change will also be in the next release of SMF 2.1.

We now generate an HMAC (https://en.wikipedia.org/wiki/HMAC) for parts of the cookie using an authentication sercet only known by the server. This prevents forgeries of the cookie by any would-be attacker.

This change breaks backwards compatibility with cookies for 2.0.15 and below. Therefore, integrations and modifications that need to tap into SMF's cookie will need to be updated.

To support both the new and the old cookie hashes, you may use this code:


require_once($sourcedir . '/Load.php');

// Use strong cookie
if (function_exists('get_auth_secret'))
$hashed_password = hash_hmac('sha1', sha1($user_info['passwd'] . $user_info['password_salt']), get_auth_secret());
// Fallback for older versions
else
$hashed_password = sha1($user_info['passwd'] . $user_info['password_salt']);


The get_auth_secret() function, which is part of Load.php, was introduced in 2.0.16 to ease the generation and retrieval of the authentication secret. If that function exists, your code will know that it should use the new password hash in the cookie. If it does not, your code should use the old hash.

Because we know that not all mods can be updated immediately, we've included a setting in the 2.0.16 admin control panel to allow the admin to disable the new cookie security for the sake of backwards compatibility with outdated mods. This setting is only available when a mod that uses the 'integrate_verify_user' hook is installed. This setting will be removed in future versions of SMF; it is only intended as a stop-gap measure until mod authors have time to update their code.

Thanks for reading!
Title: Re: SMF 2.0.16+ cookie changes
Post by: Skhilled on December 28, 2019, 09:05:03 AM
Thanks for your hard work. :)
Title: Re: SMF 2.0.16+ cookie changes
Post by: Rock Lee on December 28, 2019, 09:01:19 PM
Thanks for all the work, I think so far I don't use any mod that uses those lines (I have to see if any will give problems).


Regards!
Title: Re: SMF 2.0.16+ cookie changes
Post by: Rob Lightbody on December 29, 2019, 11:58:22 AM
Thanks for this post.  It explains why my Coppermine Gallery has stopped working.

I want to temporarily use your function to disable the new cookie security, to allow me to get Coppermine updated - I can see the checkbox "Use basic cookie authentication" but its disabled ?

Keep up the good work team, and thanks for the support so far.
Title: Re: SMF 2.0.16+ cookie changes
Post by: Shambles on December 29, 2019, 04:19:41 PM
Quote
... I can see the checkbox "Use basic cookie authentication" but its disabled ? ...

Indeed - the new cookie stuff seems to have disabled TapaTalk access.  How is this new authentication checkbox controlled?
Title: Re: SMF 2.0.16+ cookie changes
Post by: SleePy on December 29, 2019, 04:58:10 PM
The setting is only supposed to be enabled if another integration has triggered 'integrate_verify_user'.
You can directly add it to your Settings.php though to bypass this:
Code: [Select]
$cookie_no_auth_secret = true;

You will be logged out again after changing this.
Title: Re: SMF 2.0.16+ cookie changes
Post by: rbradbury on December 29, 2019, 05:25:02 PM
Thanks for the quick reply.

I added the code to Settings.php but the 'Use basic cookie authentication' checkbox remained greyed out
Title: Re: SMF 2.0.16+ cookie changes
Post by: GL700Wing on December 29, 2019, 06:45:54 PM
The setting is only supposed to be enabled if another integration has triggered 'integrate_verify_user'.
You can directly add it to your Settings.php though to bypass this:
Code: [Select]
$cookie_no_auth_secret = true;

You will be logged out again after changing this.
I made this change via Administration Center » Server Settings » Cookies and Sessions in the hope of also getting my Coppermine bridge to work again but now whenever I try to login to SMF I get the error message "You were unable to login. Please check your cookie settings."

The only way I could get back into my forum was to manually edit Settings.php and remove/comment out the line $cookie_no_auth_secret = 1;.


Edit: On another forum enabling this setting did not cause any issues as far as logging into SMF was concerned but it didn't resolve the Coppermine bridging issue ...
Title: Re: SMF 2.0.16+ cookie changes
Post by: lurkalot on December 29, 2019, 07:18:56 PM
The setting is only supposed to be enabled if another integration has triggered 'integrate_verify_user'.
You can directly add it to your Settings.php though to bypass this:
Code: [Select]
$cookie_no_auth_secret = true;

You will be logged out again after changing this.
I made this change via Administration Center » Server Settings » Cookies and Sessions in the hope of also getting my Coppermine bridge to work again but now whenever I try to login to SMF I get the error message "You were unable to login. Please check your cookie settings."

The only way I could get back into my forum was to manually edit Settings.php and remove/comment out the line $cookie_no_auth_secret = 1;.


Edit: On another forum enabling this setting did not cause any issues as far as logging into SMF was concerned but it didn't resolve the Coppermine bridging issue ...

Regarding the Coppermine bridge.  There's two new bridge files you can download to resolve this, uploaded tonight.  One for Coppermine 1.5.x https://forum.coppermine-gallery.net/index.php/topic,80028.msg387612.html#msg387612

and one for Coppermine 1.6.x https://forum.coppermine-gallery.net/index.php/topic,77951.msg387613.html#msg387613
Title: Re: SMF 2.0.16+ cookie changes
Post by: KittyGalore on December 29, 2019, 07:27:09 PM
Thanks for the quick reply.

I added the code to Settings.php but the 'Use basic cookie authentication' checkbox remained greyed out
If you change it from disabled to enabled in the Mangeserver.php it won't be greyed out.
Title: Re: SMF 2.0.16+ cookie changes
Post by: GL700Wing on December 29, 2019, 07:36:08 PM
Regarding the Coppermine bridge.  There's two new bridge files you can download to resolve this, uploaded tonight.  One for Coppermine 1.5.x https://forum.coppermine-gallery.net/index.php/topic,80028.msg387612.html#msg387612

and one for Coppermine 1.6.x https://forum.coppermine-gallery.net/index.php/topic,77951.msg387613.html#msg387613
Perfect - worked like a charm!  Thanks!!
Title: Re: SMF 2.0.16+ cookie changes
Post by: Rock Lee on December 30, 2019, 08:35:45 PM
The setting is only supposed to be enabled if another integration has triggered 'integrate_verify_user'.
You can directly add it to your Settings.php though to bypass this:
Code: [Select]
$cookie_no_auth_secret = true;

You will be logged out again after changing this.

No effect, I could not log in (at least with a secondary account) I had to comment on the entire line to allow me to enter ... I would have to do tests with a new user if the same happens but only applies to old users.


Regards!
Title: Re: SMF 2.0.16+ cookie changes
Post by: Sesquipedalian on December 31, 2019, 01:26:51 AM
We'll be simplifying the logic that controls this in 2.0.18.

In the meantime, if manually adding $cookie_no_auth_secret = 1; to your Settings.php isn't enough to make this work as you want, try also adding an entry for 'integrate_verify_user' to the settings table in your database, and give it a dummy value, as shown in the attached image.
Title: Re: SMF 2.0.16+ cookie changes
Post by: Rock Lee on December 31, 2019, 07:58:33 AM
In a new forum it doesn't give me problems but if I update my site, doing tests if I put in value 0 there is no problem but when I can be on my computer I make the change you suggest me! Thank you @Sesquipedalian
Title: Re: SMF 2.0.16+ cookie changes
Post by: aegersz on February 11, 2020, 11:48:54 AM
I followed your instructions and disabled the checkbox as required but the SA Chat mod still failes to run.

Any thoughts ?

All I could think about were the cookie changes and I have posted in the mod.