Bugzilla – Bug 119874
failed password in gnome-screensaver takes waaaaaay too long
Last modified: 2006-02-22 16:10:06 UTC
Why is it that gnome-screensaver takes so long to tell me that my password is wrong, but takes less that a second to tell me I'm right? Is the intention to hold me in suspense? Is it searching some unknown password database with deep encryption that must be decrypted to compare passwords? If there is no technical reason for this to occur can we please make that wait much shorter?
I think it's to make a brute-force attempt to guess your password take longer than it would otherwise. It's very useful against net-based attacks; I'm not sure it's necessary for local logins.
Yes, thats what's happening - it a general PAM setting. There is a yast setting, Security and Users -> Local Security, "Delay after Incorrect Login Attempt". Changing the default is a yast team and security team issue. I personally think 3 seconds is too high.
Well, YaST just displays whats in the sysconfig file. I'm not aware that YaST actually defines this value.
It's FAIL_DELAY in /etc/login.defs -> Thorsten, what do you think about changing the default value?
Do I get this right? This is an enhancement according to the standard-value of LOGIN_DELAY in /etc/login.defs? Actually, the default-value was always 3 seconds as long as I can think... but indeed one of the first things I ordinarily do after an installation is to reduce this value. Because for normal purposes it _is_ to high. Would nice to lower this value to, let's say, 1? Assigning this to the yast2-security-maintainer.
I'm all for changing the value, but the wait in gnome-screensaver is definitely longer than 3 seconds. I just typed in the wrong password twice (purposely) and counted the time it took. With a slow count I got 11 and 15 seconds. I can time it more accurately if you like, but it seems there is something else causing a further delay.
I'm not responsible for the default value (YaST doesn't set the default); Thorsten is.
If somebody does not like the default, he can change it. Since there always a few people who don't like a default, I will not change it.
Ok... Thorsten, I don't think this has anything to do with the FAIL_DELAY value, so don't worry about that. I just changed the FAIL_DELAY value to 4, 1, 0 and even 30(!), and there was absolutely no affect what so ever. Afaict this has nothing to do with FAIL_DELAY. In addition, I timed the delay slightly more accurately by using a stop watch. Without fail it took about 11.14 seconds to return the message of "Password check failed!". That is timing from the time I press the [ Enter ] key on the keyboard to the time I get that message. There is something else going on here.
So we should adjust the rest of the report.
gnome-screensaver (and xscreensaver) fail over to also trying the root password, which would add additional time.
That doesn't really explain why it seems to ignore FAIL_DELAY, does it?
Each attempt would presumably have the failed delay - ie your user and the the root user.
I misunderstood, you'd already reduced the delay. Rodrigo, can you check this out?
gnome-screensaver just calls /sbin/unix2_chkpwd command. Maybe that is the one delaying?
Could be - the setup seems a little odd. man unix2_chkpwd indicates it only works with the pam_unix module - shouldn't we just be using the regular pam stuff? OTOH, we (suse distro) apparently wrote this support, so I'm not clear on the history here.
IIRC pam_unix2 is more versatile (NIS+ etc) and not as broken as pam_unix according to it's author. One major application visible difference between the two is that pam_unix2 does not fork authentication helpers by itself to read eg /etc/shadow. You always have to call pam_unix2 with sufficient permissions. Therefore the setgid shadow unix2_chkpwd helper is used. The helper is really only suitable for simple password based authentication though, it doesn't offer a full pam interface.
The fact that it doesn't offer a full pam interface leads me to believe we should no longer be using it because of upcoming active directory and edir support for logins (among other things).
*** Bug 152357 has been marked as a duplicate of this bug. ***
This is fixed in upstream g-s which is now submitted to autobuild