Re: [BUG] hfs_find_init() sb->ext_tree NULL pointer dereference

[Clement LECIGNE]

Hi Christoph,

----- Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> On Wed, Jun 08, 2011 at 01:07:55PM +0200, Clement LECIGNE wrote:
> -snip-
> Well, it can't happen in practice.  The extent file always fits into
> the first blocks for a valid extents file.  And yes, you could

If this can't happen then it should be reasonable to ban this case.

> artifically construct a filesystem where this is not true, and if you
> want to be cool call it a security issue.  But in the end anyone who
> mounts untrusted disk images has much worse issues than this, so don't
> do it.

Yes I agree but think about the case we are a simple user on the machine
without root. For example few years ago at my university I was able to
gain root priv thanks to a vulnerability in XFS quite similar to this one
(exploit which does the evil mmap(), plug usb key, automounting, sbam).

Best,

-- 
ClÃment LECIGNE,
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/