Re: Safer ways to write an ISO onto USB stick [was Re: Repair partition after dd]

[David Christensen <dpchrist@holgerdanske.com>]

On 7/14/21 3:47 AM, Thomas Schmitt wrote:
> Hi,
>
> Brian wrote:
> > It would be nice to avoid having to have root privileges in order
> > to do 'cp <ISO> /dev/sdX' with a USB stick. A udev rule under
> > /etc/udev/rules.d/ could be a solution:
> >
> >    SUBSYSTEM=="block", ATTRS{removable}=="1", GROUP="floppy"
>
> This could have prevented the mishap, indeed, provided that /dev/sda is
> an internal SATA disk.
>
> But i think that the criterion of being "removable" does not sufficiently
> characterize a valid target for dd-ing an installation ISO, although
> being an internal disk is a strong indication for being not the right one.
>
> It is rather about the current content of the USB stick or memory card
> which should be considered.
> Best is to make an unambiguous relation between the physical stick in the
> user's hand and the target device file.
>
> My proposal for a mitigation of the currently dangerous situation is to
> see on
>    https://wiki.debian.org/XorrisoDdTarget
>
>
> Have a nice day :)
>
> Thomas


I think we've all made painful mistakes with /dev/sd* device nodes. 
Beyond identifying disks, partitions, filesystems, etc., with dmesg(1), 
lsusb(1), parted(8), e2label(8), I have developed the habit of using 
/dev/disk/by-id/* device nodes whenever possible.


David