Bug 198160

Summary:	Should have hash files for lastlog and faillog
Product:	[Fedora] Fedora	Reporter:	Russell Coker <russell>
Component:	pam	Assignee:	Tomas Mraz <tmraz>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	rawhide	CC:	bughunt, k.georgiou
Target Milestone:	---	Keywords:	FutureFeature
Target Release:	---
Hardware:	All
OS:	Linux
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Fixed In Version:		Doc Type:	Enhancement
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2010-12-06 11:16:11 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Russell Coker 2006-07-10 12:28:42 UTC

The lastlog and faillog files deliver inadequate performance when there are 
UID numbers in the >500,000,000 range.  A test on a Pentium-M 1.7GHz showed 
the "faillog" program taking over a minute of CPU time.

faillog is in the shadow-utils package but I'm filing the bug report against 
pam because of pam_tally.so and other modules that use it.

A hacky solution would be to have the same format of the faillog and lastlog 
files (with holes) but to have a hash table in a separate file that indicates 
which parts of the files are not holes.

I think that the best long-term solution is to migrate to a new file format 
and break compatibility (as we did with utmp).

Comment 1 David Tonhofer 2009-01-18 23:08:25 UTC

I second the motion to have a non-sparse representation of "faillog". For problems with the sparse representation of "lastlog", see bug#146214.

Comment 2 Tomas Mraz 2010-12-06 11:16:11 UTC

pam_faillock uses a different data structure - a file per user in a /var/run/faillock directory. This should be reasonably scalable.