67 lines
2.6 KiB
Markdown
67 lines
2.6 KiB
Markdown
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---
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date: 2022-08-18T03:10:27Z
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draft: false
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aliases: []
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categories: ['documentation', 'various']
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series: ['apprentice']
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tags: ['various', 'useful']
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chroma: true
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toc: true
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title: Linux Desktop Password Reset
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description: Simple guide to reset the password on Linux machines to which you have physical access to the disk.
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---
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Hacking stuff is usually pretty trivial.
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As long as you've got physical access that is.
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And here I'll instruct you on how to reset passwords on a Linux installation.
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Either by booting a live ISO.
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Or by plugging the drive with the installation you'd like to reset some password(s) on into another Linux machine.
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Realistically, repairing a broken installation is pretty similar.
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Although be aware that setting up the chroot may require additional steps.
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And actually fixing it would be harder than just running passwd in chroot on the installation.
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## Setup
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For passwd we don't need any fancy setup, we just need the rootfs mounted, chroot into it and run passwd.
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Run "lsblk" to identify the disk you'll need to mount.
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Then mount it to /mnt.
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Some distros have software that can mount drives automatically to some media folder.
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This is fine for passwd, but for system repair operations you'd want to unmount that if it happens and do the whole setup manually.
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For a system repair chroot setup use these additional mounts to make sure tools interacting with the system work.
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Assuming you mounted the rootfs and potentially the boot/EFI partition to /boot or /boot/efi.
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{{< highlight sh >}}mount -R /sys /mnt/sys
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mount -R /dev /mnt/dev
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mount -B /run /mnt/run
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mount --make-rslave /mnt/sys
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mount --make-rslave /mnt/dev
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mount --make-slave /mnt/run
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mount --types proc /proc /mnt/proc
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{{< /highlight >}}
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The options -R and -B for mount are short hands for \-\-rbind and \-\-bind.
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## Fixing
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For doing the password reset or other operations on the installation other than simple file edits, you just chroot into the installation.
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{{< highlight sh >}}chroot /mnt /bin/bash{{< /highlight >}}
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You may also specify a new shell or one command with options to run in the new root after the path of the root.
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Also \-\-groups with group names and \-\-userspec with names or IDs of the main user and group to use during the chroot.
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Usually you'd want to just chroot using the root user.
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And to all the stuff you need to.
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Like the password reset!
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{{< highlight sh >}}passwd{{< /highlight >}}
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And then exit the chroot shell and proceed with the cleanup before rebooting into the fixed installation.
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{{< highlight sh >}}exit{{< /highlight >}}
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## Cleanup
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Run "umount \-\-recursive" on the rootfs mount point as root.
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{{< highlight sh >}}umount -R /mnt{{< /highlight >}}
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