Bug 154030

Summary: pam_nologin locks out root as well as nonroot users
Product: Red Hat Enterprise Linux 4 Reporter: Brad Smith <brads>
Component: pamAssignee: Tomas Mraz <tmraz>
Status: CLOSED ERRATA QA Contact: Jay Turner <jturner>
Severity: high Docs Contact:
Priority: medium    
Version: 4.0CC: mark.nelson, srevivo
Target Milestone: ---   
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Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: pam-0.77-66.5 Doc Type: Bug Fix
Doc Text:
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Clone Of: Environment:
Last Closed: 2005-06-16 11:04:22 UTC Type: ---
Regression: --- Mount Type: ---
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Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Flags
Strace of mingetty denying root access while /etc/nologin exists
none
ltrace of mingetty denying root access when /etc/nologin exists none

Description Brad Smith 2005-04-06 17:28:29 UTC 
Description of problem:
According to past experience and the current pam documetation, the presense of a /etc/nologin file should prevent nonroot logins but still permit root access. However, this does not appear to be the case. 

Version-Release number of selected component (if applicable):
pam-0.77-65.1

How reproducible:
Always. To reproduce:
1) Create /etc/nologin
2) Attempt to login as root via a virtual console. Access will be denied. For any user a line like the following will be appended to /var/log/secure:

Apr  5 21:04:54 marco login[3570]: Please ignore underlying account module

Note that ssh logins as root will still succeed. This is because sshd handles interpretation of /etc/nologin internally and ignores the pam_nologin reference in /etc/pam.d/sshd (so I think that line might be superfluous). 

I will attach an strace and an ltrace of a mingetty instance failing to allow root access while /etc/nologin exists. The problem appears to be in pam_setcred(), near the end of the ltrace. However, I can't troubleshoot it much beyond that.
Comment 1 Brad Smith 2005-04-06 17:30:15 UTC 
Created attachment 112766 [details]
Strace of mingetty denying root access while /etc/nologin exists
Comment 2 Brad Smith 2005-04-06 17:31:24 UTC 
Created attachment 112767 [details]
ltrace of mingetty denying root access when /etc/nologin exists
Comment 3 Brad Smith 2005-04-06 17:33:01 UTC 
Sorry about the formatting. So much for my experiment with using links. =:\
Comment 4 Tomas Mraz 2005-04-06 17:45:07 UTC 
duplicate of bug 143750

Patch is already included in the scheduled pam update for U1.
Comment 5 Tomas Mraz 2005-04-19 15:25:31 UTC 
*** Bug 155357 has been marked as a duplicate of this bug. ***