I'm using Arch Linux on a single-user workstation with LXDE and lxde-session autologin to the regular user. I then "su" or "sudo" to root privileges, and try to run "useradd."
useradd fails on my system. This system was re-installed from scratch less than a year ago, and has had regular "pacman -Syu" run on it. I don't do much custom system administration; mainly run LXDE and vim/gcc/make as my regular user account. useradd also fails when pacman tries to run it.
I recently ran into a problem where both mariadb and percona-server would fail to start on the system after installation, and tracked it down to the mysql user not being properly created. Trying to run useradd manually, I find that that utility has broken. Googling around, people suggest this might be a problem with /etc/shadow or confg files in /etc/pam.d/, so I looked into that.
The error I get is: useradd: PAM: Authentication service cannot retrieve authentication info
Running strace on useradd, it seems quite capable of opening /etc/shadow and /etc/passwd, and getuid() returns 0 for "root":
open("/etc/pam.d/other", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=127, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1a7c0eb000
read(3, "#%PAM-1.0\nauth\t\trequired\tpam_uni"..., 4096) = 127
read(3, "", 4096) = 0
close(3) = 0
munmap(0x7f1a7c0eb000, 4096) = 0
getuid() = 0
getuid() = 0
open("/etc/login.defs", O_RDONLY) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=5519, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1a7c0eb000
read(3, "#\n# /etc/login.defs - Configurat"..., 4096) = 4096
read(3, "gular users using chfn - use\n# a"..., 4096) = 1423
read(3, "", 4096) = 0
close(3) = 0
munmap(0x7f1a7c0eb000, 4096) = 0
open("/etc/passwd", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=610, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1a7c0eb000
read(3, "root:x:0:0:root:/root:/bin/bash\n"..., 4096) = 610
close(3) = 0
munmap(0x7f1a7c0eb000, 4096) = 0
geteuid() = 0
open("/etc/shadow", O_RDONLY|O_CLOEXEC) = 3
fstat(3, {st_mode=S_IFREG|0600, st_size=413, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7f1a7c0eb000
read(3, "root:x::::::\nbin:x:14871::::::\nd"..., 4096) = 413
read(3, "", 4096) = 0
close(3) = 0
munmap(0x7f1a7c0eb000, 4096) = 0
write(2, "useradd: PAM: Authentication ser"..., 73useradd: PAM: Authentication service cannot retrieve authentication info
) = 73
The config files look fine:
[root@robot1 jwatte]# cat /etc/pam.d/useradd
#%PAM-1.0
auth sufficient pam_rootok.so
auth required pam_unix.so
account required pam_unix.so
session required pam_unix.so
password required pam_permit.so
[root@robot1 jwatte]# cat /etc/pam.d/other
#%PAM-1.0
auth required pam_unix.so
account required pam_unix.so
password required pam_unix.so
session required pam_unix.so
[root@robot1 jwatte]#
How do I take the next step in resolving and debugging this issue? Is there any debug I can find anywhere about why PAM decides this should fail? Good-old /var/log/auth.log doesn't exist anymore, and journalctl -b is not very helpful:
May 17 09:52:15 robot1 sudo[676]: pam_unix(sudo:session): session opened for user root by jwatte(uid=0)
May 17 09:52:15 robot1 useradd[677]: Authentication service cannot retrieve authentication info
May 17 09:52:15 robot1 useradd[677]: failed adding user 'mysql', data deleted
I still can't get much information out of PAM -- specifically, which module fails, at what step? I've read the code for useradd, and the code for PAM (AAAUUGH! THE GOGGLES! THEY DO NOTHING!) I ended up adding pam_warn.so to "others" and "useradd" for the "account" action, and I got one (1) more line into the journalctl:
May 17 11:04:54 robot1 useradd[29944]: pam_warn(useradd:account): function=[pam_sm_acct_mgmt] service=[useradd] terminal=[<unknown>] user=[root] ruser=[<unknown>] rhost=[<unknown>]
Does it matter that terminal, ruser, and rhost are unknown? How would I found out?
