Bug 2093166

Summary: lslogins reports incorrect "Password is locked" status
Product: Red Hat Enterprise Linux 8 Reporter: Sunny Wu <suwu>
Component: util-linuxAssignee: Karel Zak <kzak>
Status: CLOSED ERRATA QA Contact: Radka Brychtova <rskvaril>
Severity: low Docs Contact:
Priority: unspecified    
Version: 8.6CC: kzak
Target Milestone: rcKeywords: Triaged
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: util-linux-2.32.1-36.el8 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of:
: 2094216 (view as bug list) Environment:
Last Closed: 2022-11-08 10:54:48 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:
Embargoed:

Description Sunny Wu 2022-06-03 07:09:05 UTC
Description of problem:

lslogins reports incorrect "Password is locked" status

After an account is locked, `lslogins` reports incorrect "Password is locked" status. `passwd -S` reports status correctly.

~~~
# passwd -l bob
Locking password for user bob.
passwd: Success

# passwd -S bob
bob LK 2022-06-02 0 99999 7 -1 (Password locked.)

# lslogins bob
Username:                           bob                                 
UID:                                1002                                
Gecos field:                                                            
Home directory:                     /home/bob                           
Shell:                              /bin/bash                           
No login:                           no                                  
Password is locked:                 no             <<<<<=====
Password not required:              no                                  
Login by password disabled:         yes                                 
Primary group:                      bob                                 
GID:                                1002                                
Hushed:                             no                                  
Password expiration warn interval:  7                                   
Password changed:                   20:00                               
Maximum change time:                99999                               
Running processes:                  0   
~~~

I think the logic in lslogin.c is incorrect. When account is locked by `passwd -l`, two exclamation marks ("!!") are inserted in front of a password hash. The source code checks for the presence of one exclamation marks ("!").

~~~
lslogins.c

case COL_PWDLOCK:
        if (shadow) {
                if (*shadow->sp_pwdp == '!' && valid_pwd(shadow->sp_pwdp + 1))
                        user->pwd_lock = STATUS_TRUE;
        } else
                user->pwd_lock = STATUS_UNKNOWN;
        break;
~~~

Version-Release number of selected component (if applicable):
util-linux-2.32.1-35.el8.x86_64

How reproducible:
100%

Steps to Reproduce:
~~~
# useradd bob

# passwd bob
Changing password for user bob.
New password: 
Retype new password: 
passwd: all authentication tokens updated successfully.

# passwd -S bob
bob PS 2022-06-02 0 99999 7 -1 (Password set, SHA512 crypt.)

# lslogins bob
Username:                           bob                                 
UID:                                1002                                
Gecos field:                                                            
Home directory:                     /home/bob                           
Shell:                              /bin/bash                           
No login:                           no                                  
Password is locked:                 no                                  
Password not required:              no                                  
Login by password disabled:         no                                  
Primary group:                      bob                                 
GID:                                1002                                
Hushed:                             no                                  
Password expiration warn interval:  7                                   
Password changed:                   20:00                               
Maximum change time:                99999                               
Running processes:                  0                                   

Last logs:

# passwd -l bob
Locking password for user bob.
passwd: Success

# passwd -S bob
bob LK 2022-06-02 0 99999 7 -1 (Password locked.)

# lslogins bob
Username:                           bob                                 
UID:                                1002                                
Gecos field:                                                            
Home directory:                     /home/bob                           
Shell:                              /bin/bash                           
No login:                           no                                  
Password is locked:                 no             <<<<<=====
Password not required:              no                                  
Login by password disabled:         yes            <<<<<=====
Primary group:                      bob                                 
GID:                                1002                                
Hushed:                             no                                  
Password expiration warn interval:  7                                   
Password changed:                   20:00                               
Maximum change time:                99999                               
Running processes:                  0                                   

Last logs:

# cat /etc/passwd | grep bob
bob:x:1002:1002::/home/bob:/bin/bash

# cat /etc/shadow | grep bob
bob:!!$6$.18513c.OKQEXCS/$PcBAvB<...>:19146:0:99999:7:::

# vi /etc/shadow

# cat /etc/shadow | grep bob
bob:!$6$.18513c.OKQEXCS/$PcBAvB<...>:19146:0:99999:7:::

# passwd -S bob
bob LK 2022-06-02 0 99999 7 -1 (Password locked.)

# lslogins bob
Username:                           bob                                 
UID:                                1002                                
Gecos field:                                                            
Home directory:                     /home/bob                           
Shell:                              /bin/bash                           
No login:                           no                                  
Password is locked:                 yes            <<<<<=====
Password not required:              no                                  
Login by password disabled:         no             <<<<<=====
Primary group:                      bob                                 
GID:                                1002                                
Hushed:                             no                                  
Password expiration warn interval:  7                                   
Password changed:                   20:00                               
Maximum change time:                99999                               
Running processes:                  0                                   

Last logs:
~~~

Actual results:
"Password is locked" shows "no" when account is locked.

Expected results:
"Password is locked" shows "yes" when account is locked.

Additional info:

Comment 1 Karel Zak 2022-06-07 07:20:11 UTC
Good catch. It seems the lslogins code follows shadow(5) documentation rather than a real way of how passed(1) works.

Fixed in upstream repository:
https://github.com/util-linux/util-linux/commit/c51cba1e838ae7e36a843ec785543492bb8737cd

Comment 8 errata-xmlrpc 2022-11-08 10:54:48 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (util-linux bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2022:7783

Comment 9 Sunny Wu 2022-12-23 15:16:48 UTC
What is the definition of "Login by password disabled"?

Password hash field of shadow file of a new user account without password defined contains "!!". The user is not (and should not be able) to login with password. The status of this check item has been changed to "no" in util-linux-2.32.1-38.

=========================
RHEL8.6:

# rpm -qa | grep util-linux
util-linux-2.32.1-35.el8.x86_64

# useradd test-user

# grep test-user /etc/passwd
test-user:x:1003:1003::/home/test-user:/bin/bash

# grep test-user /etc/shadow
test-user:!!:19349:0:99999:7:::

# lslogins test-user
Username:                           test-user                           
UID:                                1003                                
Gecos field:                                                            
Home directory:                     /home/test-user                     
Shell:                              /bin/bash                           
No login:                           no                                  
Password is locked:                 no                                  
Password not required:              no                                  
Login by password disabled:         yes                                 
Primary group:                      test-user                           
GID:                                1003                                
Hushed:                             no                                  
Password expiration warn interval:  7                                   
Password changed:                   19:00                               
Maximum change time:                99999                               
Running processes:                  0                                   

Last logs:

=====
RHEL8.7:

# rpm -qa | grep util-linux
util-linux-2.32.1-38.el8.x86_64

# useradd test-user

# grep test-user /etc/passwd
test-user:x:1004:1004::/home/test-user:/bin/bash

# grep test-user /etc/shadow
test-user:!!:19349:0:99999:7:::

# lslogins test-user
Username:                           test-user                           
UID:                                1004                                
Gecos field:                                                            
Home directory:                     /home/test-user                     
Shell:                              /bin/bash                           
No login:                           no                                  
Password is locked:                 yes                                 
Password not required (empty):      yes                                 
Login by password disabled:         no                                  
Primary group:                      test-user                           
GID:                                1004                                
Hushed:                             no                                  
Password expiration warn interval:  7                                   
Password changed:                   10:00                               
Maximum change time:                99999                               
Running processes:                  0                                   

Last logs:

Comment 11 Karel Zak 2023-07-17 10:57:24 UTC
(In reply to Sunny Wu from comment #9)
> What is the definition of "Login by password disabled"?

This field is pretty confusing from the beginning (sorry for that). It checks the validity of the password (and valid is also an empty password)
independently on "!" or "*" prefixes in the password field. This is a mistake because it's interpreted by users as 
the final conclusion about the login by a password. The description is wrong.

Maybe the best would be to introduce new info about the validity of the hash (independently of prefix) and keep "Login by password disabled" as real final conclusion about login. Something like:

 Password is locked: yes
 Password hash is valid: no
 Password not required (empty): yes
 Login by password disabled: yes

for "!!".

Does it make more sense?