Bug 1038910

Summary:	fprintd: do not show password if user enters one
Product:	Red Hat Enterprise Linux 6	Reporter:	Ratul Gupta <ratulg>
Component:	util-linux-ng	Assignee:	Karel Zak <kzak>
Status:	CLOSED NOTABUG	QA Contact:	qe-baseos-daemons
Severity:	medium	Docs Contact:
Priority:	unspecified
Version:	6.6	CC:	tpelka
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2015-06-03 11:16:55 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:

Description Ratul Gupta 2013-12-06 06:42:03 UTC

Description of problem: 
Users are useg to entering passwords at login prompts and the like.
It would be nice if libpam-fprintd could swallow the input like
password prompts do, instead of prominentally displaying the user's password
if they type it in.

References:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=731382

Additional Information:
Also affects rhel-7, fedora-all.

Comment 2 Bastien Nocera 2014-03-25 07:16:50 UTC

This is a design problem with PAM, worked around by various front-ends (most preeminently gdm, which uses multiple PAM stacks).

Given that this risks breaking a number of PAM front-ends, and concern all PAM modules (say, smartcard logins), this should be fixed in PAM if at all.

Comment 3 Tomas Mraz 2014-03-25 08:54:44 UTC

PAM library on itself does not have any knowledge about the environment it operates in. I don't really see a way how PAM library could mitigate this. I suppose it might be reasonable to workaround it in the login by switching off the TTY echo before calling pam_authenticate. However there would be a possibility of breaking other modules which might potentially ask for additional non-password information which is supposed to be echoed.

Comment 4 Karel Zak 2015-06-03 11:16:55 UTC

Closing... 

I don't think we want to play any nasty games with ECHO in login(1) to avoid situation when user accidentally enters a password when there is no password prompt.

It's unreal wish to be resistant to all possible use-cases and user mistakes. It's user responsibility to be careful with password...