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. I'll edit the commit and kconfig messages to be more precise. Regards, Anisse -- 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>