Re: mount loop devices not works in schroot

[Srinuvasan Arjunan <srinuvasanasv@gmail.com>]

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On Thursday, January 18, 2024 at 1:26:32 PM UTC+5:30 Jan Kiszka wrote:

On 18.01.24 08:16, Srinuvasan Arjunan wrote: 
> Hi All, 
> 
>              Presently we migrated the chroot to sbuildchroot and one of 
> my image creation part i try to mount some temporary file system as a 
> loop device and do create volumes and other stuffs. 
> 
> Here i could see am not able to mount the file system as a loop device 
> specifically in chroot. 
> 
> reproduce steps: 
>   
> 1. chroot into the created session  
> 2. dd if=/dev/zero of=ext4.img bs=4k count=2048 
> 3.mkfs.ext4 ext4.img 
> 4. mnt=$(mktemp -d) 
> 5.  mount -o loop 'ext4.img' "${mnt}" 
> 
> when i mount this ext4.img as a loop devices it throws the below error: 
> Error: "mount: /tmp/tmp.7oJoEpL0vt: mount failed: Operation not 
permitted."  
> 
> But the above steps are working fine in my host machine. 
> 
> I hope we need to install the loop module in chroot or any other 
> suggestion that would be helpful to mount loop devices in schroot 
sessions. 
> 
> Note:  losetup also not works in schroot. 
> 

I don't think you can run such stuff in the schroot, and you will surely 
not be able to once we fully de-privilege the build. That's why I 
suggested to you already to get rid of this loop-mount requirement. 

Jan 

-- 
Siemens AG, Technology 
Linux Expert Center



Thanks jan for your quick reply, but still i didn't get this line "and you 
will surely
not be able to once we fully de-privilege the build"

Can you please provide more information on the above line

but i could see this was working fine in existing BUILDCHROOT.

Many thanks,
Srinu 

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