On Mon 2015-05-18 14:41:19, Anisse Astier wrote: > On Mon, May 18, 2015 at 1:21 PM, Pavel Machek <pavel@xxxxxx> wrote: > > On Thu 2015-05-14 16:19:47, Anisse Astier wrote: > >> This new config option will sanitize all freed pages. This is a pretty > >> low-level change useful to track some cases of use-after-free, help > >> kernel same-page merging in VM environments, and counter a few info > >> leaks. > > > > Could you document the "few info leaks"? We may want to fix them for > > !SANTIZE_FREED_PAGES case, too... > > > > I wish I could; I'd be sending patches for those info leaks, too. > > What I meant is that this feature can also be used as a general > protection mechanism against a certain class of info leaks; for > example, some drivers allocating pages that were previously used by > other subsystems, and then sending structures to userspace that > contain padding or uninitialized fields, leaking kernel pointers. > Having all pages cleared unconditionally can help a bit in some cases > (hence "a few"), but it's of course not an end-all solution. Ok. So there is class of errors where this helps, but you are not aware of any such errors in kernel, so you can't fix them... Right? > I'll edit the commit and kconfig messages to be more precise. Thanks, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- 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>