[PATCH v3 1/2] initmem: introduce CONFIG_INIT_ALL_MEMORY and CONFIG_INIT_ALL_STACK

[Alexander Potapenko]

On Tue, Apr 9, 2019 at 12:15 AM Randy Dunlap <rdunlap at infradead.org> wrote:
>
> On 4/8/19 10:04 AM, Alexander Potapenko wrote:
> > diff --git a/security/Kconfig.initmem b/security/Kconfig.initmem
> > new file mode 100644
> > index 000000000000..5e49a55382ad
> > --- /dev/null
> > +++ b/security/Kconfig.initmem
> > @@ -0,0 +1,29 @@
> > +menu "Initialize all memory"
> > +
> > +config CC_HAS_AUTO_VAR_INIT
> > +     def_bool $(cc-option,-ftrivial-auto-var-init=pattern)
> > +
> > +config INIT_ALL_MEMORY
> > +     bool "Initialize all memory"
> > +     default n
> > +     help
> > +       Enforce memory initialization to mitigate infoleaks and make
> > +       the control-flow bugs depending on uninitialized values more
> > +       deterministic.
> > +
> > +if INIT_ALL_MEMORY
> > +
> > +config INIT_ALL_STACK
> > +     bool "Initialize all stack"
> > +     depends on INIT_ALL_MEMORY
>
> This "depends on" is redundant with the "if INIT_ALL_MEMORY" above it.
Ack, thank you!
> Similar comment for patch 2/2 and INIT_ALL_HEAP.
>
> > +     depends on CC_HAS_AUTO_VAR_INIT || (HAVE_GCC_PLUGINS && PLUGIN_HOSTCC != "")
> > +     select GCC_PLUGINS if !CC_HAS_AUTO_VAR_INIT
> > +     select GCC_PLUGIN_STRUCTLEAK if !CC_HAS_AUTO_VAR_INIT
> > +     select GCC_PLUGIN_STRUCTLEAK_BYREF_ALL if !CC_HAS_AUTO_VAR_INIT
> > +     default y
> > +     help
> > +       Initialize uninitialized stack data with a fixed pattern
> > +       (0x00 in GCC, 0xAA in Clang).
> > +
> > +endif # INIT_ALL_MEMORY
> > +endmenu
>
>
> --
> ~Randy



-- 
Alexander Potapenko
Software Engineer

Google Germany GmbH
Erika-Mann-Straße, 33
80636 München

Geschäftsführer: Paul Manicle, Halimah DeLaine Prado
Registergericht und -nummer: Hamburg, HRB 86891
Sitz der Gesellschaft: Hamburg