kern.geom.debugflags=16 does NOT allow me to write to device
Test Rat
ttsestt at gmail.com
Sun Aug 7 07:32:37 UTC 2011
Peter Schuller <peter.schuller at infidyne.com> writes:
[...]
> In addition, geom(4) still has:
>
> 0x10 (allow foot shooting)
> Allow writing to Rank 1 providers. This would, for example,
> allow the super‐user to overwrite the MBR on the root disk or
> write random sectors elsewhere to a mounted disk. The implica‐
> tions are obvious.
>
> In addition, geom/geom_subr.c has:
>
> /* If foot-shooting is enabled, any open on rank#1 is OK */
> if ((g_debugflags & 16) && pp->geom->rank == 1)
> ;
>
> I wonder if the problem is that it's not of rank 1 because I'm writing
> to the slice's first second rather than the MBR... That's now feeling
> pretty likely and can perhaps explain lots of confusion that seems to
> exist based on Googling.
[...]
The issue still seems unanswered. For example, this guide
http://wiki.freebsd.org/RootOnZFS/ZFSBootPartition
silently avoids explaining why zroot on MBR & BSD should be exported.
If gpart is ever fixed I still think shooting the foot on rank > 1 is
useful for things like testing FS for corruption without accidentally
destroying partition table if operating on rank == 1.
More information about the freebsd-fs
mailing list