cannot log in, password not recognised

thea · 2020-06-04 19:42:11

First off, this is my mistake. I was just out of the hospital, and tired. Shadow was updated, and I simply replaced the former shadow file with the new (pacnew). Rebooted and of course no passwords, so I can't log in, no root either, of course. All I need to do is to rename the old shadow file (now shadow.old), but how to do this? Because I cannot log in, I can't mount a rescue disk. I have access to the grub shell, but I don't know if that could help. Thanks in advance for any useful tips.

jasonwryan · 2020-06-04 19:55:23

Boot from the live media and chroot in, then set your user's password.

Slithery · 2020-06-04 19:56:37

Just boot from the Installation USB, mount your root filesystem and rename the file from there.

seth · 2020-06-04 20:07:31

Or just pass "systemd.unit=rescue.target" to the kernel commandline.
Or "init=/bin/bash".

thea · 2020-06-04 22:54:43

Thanks for the tips! Unfortunately, I can't mount the installation USB, since I can't login, it isn't automatically detected. And the only utility I seem to have is the grub shell.

What exactly is the root password in shadow.pacnew?

loqs · 2020-06-04 23:05:11

Can you select booting from the installation media using the firmwares boot menu? The media needs to be connected when the system boots.

thea · 2020-06-05 07:25:00

OK, thanks, I had forgotten about setting the boot order. So now the installation disk is booted and I have a root@archiso prompt. cd /etc and ls show:
shadow
shadow-

They both appear to be the same.

I have read a bit about editing the shadow file, and about using vipw, which is totally unfamiliar to me. Obviously I am not wanting to make further mistakes here. What should I do now?

jasonwryan · 2020-06-05 07:27:06

Don't edit the file by hand. Use passwd to create a new password for your user.

# edit: from the chroot.

Last edited by jasonwryan (2020-06-05 07:27:51)

thea · 2020-06-05 08:45:53

I tried setting the password, but it failed. I have read the Arch instructions on resetting a lost root password.

In particular:

at prompt root@archiso:
mount /dev/sda1 /mnt
passwd --root /dev/sda1 thea
passwd: cannot chdir to chroot directory /dev/sda1: Not a directory

V1del · 2020-06-05 08:52:41

Your chroot directory to pass to that command would be /mnt not /dev/sda... or just actually chroot into it with arch-chroot and run passwd normally.

thea · 2020-06-05 10:29:34

Thanks V1del! I have a feeling that am working on the wrong filesystem. Here are the results of lsblk:

loop0 /run/archiso/sfs/airootfs
sda disk
sda1 part
sdb disk
sdb1 part /run/archiso/bootmnt
nve0n1 disk
nve0n1p1 part
nve0n1p2 part
nve0n1p3 part
nve0n1p4 part

the boot partition is on nve0n1. sda is a separate (second) hard drive. sdb is an installation USB.

My understanding is that I have to mount the boot file syste. How do I do this?

seth · 2020-06-05 11:21:10

You want to mount the root partition, not the boot partition (the one that holds "/", not "/boot") and you do that by simply creating a mountpoint (eg. /mnt) and mounting it there:

mount /dev/nve0n1p2 /mnt

However and again: you can tell the system to boot a root shell, no password required. See comment #4 and also https://wiki.archlinux.org/index.php/Re … t_password

thea · 2020-06-05 14:41:06

I followed these steps:

mount /dev/nvme0n1p2 /mnt
passwd --root /mnt thea
passwd: Cannot determine your user name.

seth · 2020-06-05 14:44:38

cat /mnt/etc/passwd
grep thea /mnt/etc/passwd

thea · 2020-06-05 14:56:42

cat /mnt/etc/passwd -- no such file

however
cd /mnt
cd /etc
nano passwd

works.
There is no user thea, but there is root:
root:x:0:0::/root:/usr/bin/zsh

Scimmia · 2020-06-05 15:01:33

you cd'ed to /etc on the ISO, what did you expect? Notice that's a full path, not a relative one.

Last edited by Scimmia (2020-06-05 15:02:55)

seth · 2020-06-05 15:03:09

cat /mnt/etc/passwd -- no such file

Most likely means that you failed to mount the root partition.

thea · 2020-06-05 15:11:22

when I try again:
mount /dev/nvme0n1p2 /mnt

I get the message:
mount: /mnt: /dev/nvme0n1p2 already mounted on /mnt.

Scimmia · 2020-06-05 15:11:49

And what's there?

thea · 2020-06-05 15:16:05

cd /mnt
ls

casper-B323-B057 dists pool recovery.conf

seth · 2020-06-05 15:17:10

Well, that's not the root partition.
"lsblk -f"?

thea · 2020-06-05 15:26:45

It's arch, no doubt about that.

here are results of lsblk -f, just for the main drive:
nvme0n1
p1 vfat EFI
p2 vfat RECOVERY /mnt
p3 ext4
p4 swap

I believe the root partition is p3. Does that make sense?

seth · 2020-06-05 15:27:27

Yup.

thea · 2020-06-05 15:35:07

I mounted p3, and set the password for root. This password is still not recognised when I try to login normally.

thea · 2020-06-05 15:59:40

[SOLVED] After identifying the root partition, I chrooted into this partition and used passwd to change the passwords. This was successful and I am now able to login normally. Many thanks to those who assisted me!

Last edited by thea (2020-06-05 16:01:52)

Arch Linux

#1 2020-06-04 19:42:11

cannot log in, password not recognised

#2 2020-06-04 19:55:23

Re: cannot log in, password not recognised

#3 2020-06-04 19:56:37

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#4 2020-06-04 20:07:31

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#5 2020-06-04 22:54:43

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#6 2020-06-04 23:05:11

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#7 2020-06-05 07:25:00

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#8 2020-06-05 07:27:06

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#9 2020-06-05 08:45:53

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#10 2020-06-05 08:52:41

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#11 2020-06-05 10:29:34

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#13 2020-06-05 14:41:06

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