Re: [PATCH] make kernel ignore bogus partitions

[Andrew Morton <akpm@osdl.org>]

"Mike Miller (OS Dev)" <mikem@beardog.cca.cpqcorp.net> wrote:
>
> On Tue, May 09, 2006 at 12:41:38PM -0700, Andrew Morton wrote:
> > "Mike Miller (OS Dev)" <mikem@beardog.cca.cpqcorp.net> wrote:
> > >
> > > Patch 1/1
> > > Sometimes partitions claim to be larger than the reported capacity of a
> > > disk device. This patch makes the kernel ignore those partitions.
> > > 
> > > Signed-off-by: Mike Miller <mike.miller@hp.com>
> > > Signed-off-by: Stephen Cameron <steve.cameron@hp.com>
> > > 
> > > Please consider this for inclusion.
> > > 
> > > 
> > >  fs/partitions/check.c |    5 +++++
> > >  1 files changed, 5 insertions(+)
> > > 
> > > --- linux-2.6.14/fs/partitions/check.c~partition_vs_capacity	2006-01-06 09:32:14.000000000 -0600
> > > +++ linux-2.6.14-root/fs/partitions/check.c	2006-01-06 11:24:50.000000000 -0600
> > > @@ -382,6 +382,11 @@ int rescan_partitions(struct gendisk *di
> > >  		sector_t from = state->parts[p].from;
> > >  		if (!size)
> > >  			continue;
> > > +		if (from+size-1 > get_capacity(disk)) {
> > > +			printk(" %s: p%d exceeds device capacity, ignoring.\n", 
> > > +				disk->disk_name, p);
> > > +			continue;
> > > +		}
> > >  		add_partition(disk, p, from, size);
> > >  #ifdef CONFIG_BLK_DEV_MD
> > >  		if (state->parts[p].flags)
> > 
> > Shouldn't that be
> > 
> > 	if (from+size > get_capacity(disk)) {
> > 
> > ?
> > 
> Since the partition size is 0-based this is correct:
> 
> 	if (from+size-1 > get_capacity(disk)) {
> 

Don't think so.

If `from' is 0 and `size' is 1025 and get_capacity() is 1024 then we have

	if (1024 > 1024)

which returns false.