Re: [kernel-hardening] Re: [PATCH v6 03/11] mm, x86: Add support for eXclusive Page Frame Ownership (XPFO)

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Dave,

On Mon, Nov 13, 2017 at 02:46:25PM -0800, Dave Hansen wrote:
> On 11/13/2017 02:20 PM, Dave Hansen wrote:
> > On 11/09/2017 05:09 PM, Tycho Andersen wrote:
> >> which I guess is from the additional flags in grow_dev_page() somewhere down
> >> the stack. Anyway... it seems this is a kernel allocation that's using
> >> MIGRATE_MOVABLE, so perhaps we need some more fine tuned heuristic than just
> >> all MOVABLE allocations are un-mapped via xpfo, and all the others are mapped.
> >>
> >> Do you have any ideas?
> > 
> > It still has to do a kmap() or kmap_atomic() to be able to access it.  I
> > thought you hooked into that.  Why isn't that path getting hit for these?
> 
> Oh, this looks to be accessing data mapped by a buffer_head.  It
> (rudely) accesses data via:
> 
> void set_bh_page(struct buffer_head *bh,
> ...
> 	bh->b_data = page_address(page) + offset;

Ah, yes. I guess there will be many bugs like this :). Anyway, I'll
try to cook up a patch.

Thanks!

Tycho

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>



[Index of Archives]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]
  Powered by Linux