On 07/04/17 at 04:00pm, Thomas Gleixner wrote:
> On Tue, 4 Jul 2017, Baoquan He wrote:
> > +/* Marks if efi mirror regions have been found and handled. */
> > +static bool efi_mirror_found;
> > +
> > +static void process_efi_entry(unsigned long minimum, unsigned long
> > image_size)
> > +{
> > + struct efi_info *e = &boot_params->efi_info;
> > + struct mem_vector region;
> > + efi_memory_desc_t *md;
> > + unsigned long pmap;
> > + char *signature;
> > + u32 nr_desc;
> > + int i;
> > +
> > +
> > +#ifdef CONFIG_EFI
> > + signature = (char *)&boot_params->efi_info.efi_loader_signature;
> > +#endif
>
> So if CONFIG_EFI=n you happily dereference the uninitialized signature
> pointer ...
Right, this is a mistake. Thanks for pointing it out. I should have
checked if the pointer is NULL.
In fact I just referred to code in setup_arch(). Now I have a question,
though CONFIG_EFI=y but efi firmware is not enabled,
boot_params.efi_info.efi_loader_signature should be initilized to 0.
Then below code is also problematic.
#ifdef CONFIG_EFI
if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
EFI32_LOADER_SIGNATURE, 4)) {
set_bit(EFI_BOOT, &efi.flags);
} else if (!strncmp((char *)&boot_params.efi_info.efi_loader_signature,
EFI64_LOADER_SIGNATURE, 4)) {
set_bit(EFI_BOOT, &efi.flags);
set_bit(EFI_64BIT, &efi.flags);
}
if (efi_enabled(EFI_BOOT))
efi_memblock_x86_reserve_range();
#endif
>
> Why is process_efi_entry() invoked at all if EFI is not enabled?
Yeah, and it's better to check if CONFIG_EFI is enabled before
invocation of process_efi_entry(). Let me change it as below and repost.
Thanks again for looking into this patchset.
+#ifdef CONFIG_EFI
process_efi_entry(minimum, image_size);
+#endif
>
> > + if (strncmp(signature, EFI32_LOADER_SIGNATURE, 4) &&
> > + strncmp(signature, EFI64_LOADER_SIGNATURE, 4))
> > + return;
> > +
>
> Thanks,
>
> tglx
