On Sat, 15 Dec 2007, Adrian Bunk wrote: > On Wed, Dec 12, 2007 at 05:01:51AM +0000, Hugh Dickins wrote: > > On Tue, 11 Dec 2007, Chuck Ebbert wrote: > > > On 11/28/2007 01:55 PM, Hugh Dickins wrote: > > > > tmpfs was misconverted to __GFP_ZERO in 2.6.11. There's an unusual > > > > case in > > > > which shmem_getpage receives the page from its caller instead of > > > > allocating. > > > > We must cover this case by clear_highpage before SetPageUptodate, as > > > > before. > > > > > > > > Signed-off-by: Hugh Dickins <[EMAIL PROTECTED]> > > > > --- > > > > > > What are the symptoms of the bug this fixes? > > > > I've not seen it in practice, just noticed it while working on that > > area in the code. What's the polite way of describing these things > > in public? It's a vulnerability which might allow an attacker to > > access data from inside the kernel which should have been zeroed - > > in very limited circumstances I'd prefer not to have to devise and > > announce. > > > > It would also be wrong data, so could for example crash any program > > rightly relying on uninitialized static data to be zeroed - in the > > unlikely event that its data was coming via this route (in most setups > > it never can do, perhaps I'd conclude that's true of all setups). It > > has escaped notice for nearly three years, so it's not a commonplace. > > > > Further discussion offline if you like! > > Can we get or is there already a CVE number?
I've not asked for one, so I don't suppose there is one: do go ahead and get one if you wish (though of course it would have been better earlier, so 2.6.22.15 and 2.6.23.10 could have cited it along with their fix: sorry about that). Hugh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
