On 07/09/17 at 07:11am, Kees Cook wrote:
> On Sun, Jul 9, 2017 at 5:37 AM, Baoquan He <b...@redhat.com> wrote:
> > Signed-off-by: Baoquan He <b...@redhat.com>
> > +/* Marks if efi mirror regions have been found and handled. */
> > +static bool efi_mirror_found;
>
> I think this is only ever checked once? How about having
> process_efi_entries return bool to indicate if mirror was found? Also,
> that function should be behind #ifdef. Let's do something like this:
>
>
> > +
> > +static void process_efi_entries(unsigned long minimum,
> > + unsigned long image_size)
>
> #ifdef CONFIG_EFI
> /* Returns true if mirror region found (and further scanning should stop) */
Well, here it might be not like that. The mirror regions could be multiple,
we need find and process each of them to add slots.
> static bool process_efi_entries(...)
> {
> ...
> }
> #else
> static inline bool process_efi_entries(...)
> {
> return false;
> }
> #endif
>
> Then:
>
> > +#ifdef CONFIG_EFI
> > + process_efi_entries(minimum, image_size);
> > + if (efi_mirror_found)
> > + return slots_fetch_random();
> > +#endif
>
> Can become:
>
> if (process_efi_entries(minimum, image_size))
> return slots_fetch_random()
>
> and no #ifndef needed here.
>
> > +
> > process_e820_entries(minimum, image_size);
> > return slots_fetch_random();
> > }
> > @@ -652,7 +708,7 @@ void choose_random_location(unsigned long input,
> > */
> > min_addr = min(*output, 512UL << 20);
> >
> > - /* Walk e820 and find a random address. */
> > + /* Walk available memory entries to find a random address. */
> > random_addr = find_random_phys_addr(min_addr, output_size);
> > if (!random_addr) {
> > warn("Physical KASLR disabled: no suitable memory region!");
> > --
> > 2.5.5
> >
>
> Otherwise, if the EFI logic is good, this looks sensible.
>
> Thanks for splitting up the patches!
>
> -Kees
>
> --
> Kees Cook
> Pixel Security
