root access on bootup when core-files not found?

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root access on bootup when core-files not found?

Simon Campese
Hello,

I recently set up a fresh, fully luks-encrypted debian machine (testing
release) with a typo in my crypttab (for a system critical partition)
using the lenny RC2 installer.
After a reboot, the system tries to open the mistyped partition to be
mounted on the critical path (in this case /var) but doesn't succeed. It
then tries to su a maintenance shell (which it can't, as I disabled root
logins), prints an error message (similar to "su failed, root login
disabled") and then nevertheles drops to a root shell (without me entering
a password).

As I am quite new to Debian, this might be wanted behaviour but common
sense tells me otherwise. I had root access to all mounted partitions so
far without authenticating.

I currently don't have time to investigate further but nevertheless
thought that this could be of interest. By my understanding this behaviour
should be reproduceable without using luks (by just deliberately placing
an invalid "critical"-mountpoint into fstab or even by deleting a
"critical" system directory and then trying to boot, both with disabled
root-logins).


Apologies for this incomplete posting,

Simon


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Re: root access on bootup when core-files not found?

Simon Campese
Just answered the question myself: The system entered single user mode and
that cleary IS wanted behaviour...


Sorry for bothering,

Simon

Simon Campese wrote:

> Hello,
>
> I recently set up a fresh, fully luks-encrypted debian machine (testing
> release) with a typo in my crypttab (for a system critical partition)
> using the lenny RC2 installer.
> After a reboot, the system tries to open the mistyped partition to be
> mounted on the critical path (in this case /var) but doesn't succeed. It
> then tries to su a maintenance shell (which it can't, as I disabled root
> logins), prints an error message (similar to "su failed, root login
> disabled") and then nevertheles drops to a root shell (without me entering
> a password).
>
> As I am quite new to Debian, this might be wanted behaviour but common
> sense tells me otherwise. I had root access to all mounted partitions so
> far without authenticating.
>
> I currently don't have time to investigate further but nevertheless
> thought that this could be of interest. By my understanding this behaviour
> should be reproduceable without using luks (by just deliberately placing
> an invalid "critical"-mountpoint into fstab or even by deleting a
> "critical" system directory and then trying to boot, both with disabled
> root-logins).
>
>
> Apologies for this incomplete posting,
>
> Simon
>
>
> --
> To UNSUBSCRIBE, email to [hidden email]
> with a subject of "unsubscribe". Trouble? Contact
> [hidden email]
>
>


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