Bug 1026921

Summary:	useless similarity check
Product:	Red Hat Enterprise Linux 7	Reporter:	Karel Volný <kvolny>
Component:	libpwquality	Assignee:	Tomas Mraz <tmraz>
Status:	CLOSED WONTFIX	QA Contact:	BaseOS QE Security Team <qe-baseos-security>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	7.0
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
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Fixed In Version:		Doc Type:	Bug Fix
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Clone Of:		Environment:
Last Closed:	2013-11-05 16:48:58 UTC	Type:	Bug
Regression:	---	Mount Type:	---
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Description Karel Volný 2013-11-05 16:23:16 UTC

Description of problem:
I've just wanted to correct wrongly entered password (due to different keyboard layout) but was disallowed to. This makes no sense, as it can be easily workarounded by changing to something completely different at first, then changing to whatever you need, it just annoys the user.

Version-Release number of selected component (if applicable):
passwd-0.79-1.el7

How reproducible:
always

Steps to Reproduce:
1. run passwd (as ordinary user)
2. try to change the password to nearly the same as before just with one character different

Actual results:
you get BAD PASSWORD error and cannot use the new password

Expected results:
the password gets changed

Additional info:

Comment 2 Miloslav Trmač 2013-11-05 16:38:41 UTC

This check happens in *pwquality (... and is configured in system-auth, which Tomáš owns as well.)

Reassigning for him to consider.

FWIW, the workaround you propose can be, and is in some deployments, prevented by setting up a minimal password validity, and potentially remembering more past passwords.

Comment 3 Tomas Mraz 2013-11-05 16:48:38 UTC

You can also set up minimal number of days before you're allowed to change your password again.

The similarity check was there for a very long time and I don't think we should remove it. Basically all the checks in libpwquality/cracklib can be sometimes annoying but with this attitude we could drop pam_pwquality from the system-auth altoghether.