[stgt] [PATCH 2/2] tgt-admin: check if device is mounted on /

[Tomasz Chmielewski]

Eli Dorfman schrieb:
> On Mon, Sep 1, 2008 at 4:31 PM, Tomasz Chmielewski <mangoo at wpkg.org> wrote:
>> Doron Shoham schrieb:
>>> check if device is mounted on / before allocating it
>> I'm not very familiar with distributed filesystems, like GFS2 or OCFS2 - but
>> what if someone wants to use them?
>>
>> Can't it be that in such case underlying device is mounted on the target as
>> well?
>>
> In any case target's system disk should not be allocated to the initiator.
> The purpose of this patch is to deny such allocation.

Generally, any filesystem mounted on the target should not be allocated 
to initiators. Disallowing / (i.e., /dev/sda1), but allowing /usr (i.e., 
/dev/sda2) or swap is certainly not a good idea.

The info can be fetched from /etc/mtab (unless we have a system with 
read-only /etc, where /etc/mtab could be a link to /proc/mounts - I 
think /proc/mounts doesn't always show an underlying device where rootfs 
sits). Also, parsing /proc/swaps would be useful.

But what if someone has rootfs on /dev/mtd0, mtd0 consists of /dev/sda1 
and /dev/sdb1 - and wants to allocate /dev/sdb to initiators? Not to say 
LVM, dm-crypt devices, etc... - it looks like there are lots of 
possibilities for an admin to break the system ;)


If someone is brave (or uses a distributed fs on the target) and really 
wants to allow initiators access to a mounted filesystem, we could add a 
separate option for that ("allow-mounted")?
Although I guess it wouldn't have many users today.


-- 
Tomasz Chmielewski
http://wpkg.org



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