Re: [PATCH 11/18] Hibernate: introduced RSA key-pair to verify signature of snapshot

[joeyli <jlee@suse.com>]

Hi Pavel, 

於 日，2013-08-25 於 18:25 +0200，Pavel Machek 提到：
> On Thu 2013-08-22 19:01:50, Lee, Chun-Yi wrote:
> > Introduced a hibernate_key.c file to query the key pair from EFI variables
> > and maintain key pair for check signature of S4 snapshot image. We
> > loaded the private key when snapshot image stored success.
> > 
> > This patch introduced 2 EFI variables for store the key to sign S4 image and
> > verify signature when S4 wake up. The names and GUID are:
> >   S4SignKey-fe141863-c070-478e-b8a3-878a5dc9ef21
> >   S4WakeKey-fe141863-c070-478e-b8a3-878a5dc9ef21
> > 
> > S4SignKey is used by EFI bootloader to pass the RSA private key that packaged
> > by PKCS#8 format, kernel will read and parser it when system boot and reload
> > it when S4 resume. EFI bootloader need gnerate a new private key when every
> > time system boot.
> > 
> > S4WakeKey is used to pass the RSA public key that packaged by X.509
> > certificate, kernel will read and parser it for check the signature of
> > S4 snapshot image when S4 resume.
> > 
> > The follow-up patch will remove S4SignKey and S4WakeKey after load them
> > to kernel for avoid anyone can access it through efivarfs.
> > 
> > v3:
> > - Load S4 sign key before ExitBootServices.
> >   Load private key before ExitBootServices() then bootloader doesn't need
> >   generate key-pair for each booting:
> >    + Add setup_s4_keys() to eboot.c to load S4 sign key before ExitBootServices.
> >    + Reserve the memory block of sign key data blob in efi.c
> > - In Makefile, moved hibernate_keys.o before hibernate.o for load S4 sign
> >   key before check hibernate image. It makes sure the new sign key will be
> >   transfer to resume target kernel.
> > - Set "depends on EFI_STUB" in Kconfig
> > 
> > v2:
> > Add CONFIG_SNAPSHOT_VERIFICATION for build of hibernate_keys.c depend on
> > Kconfig.
> > 
> > Cc: Matthew Garrett <mjg59@srcf.ucam.org>
> > Cc: Takashi Iwai <tiwai@suse.de>
> > Reviewed-by: Jiri Kosina <jkosina@suse.cz>
> > Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
> 
> 
> > --- a/arch/x86/boot/compressed/eboot.c
> > +++ b/arch/x86/boot/compressed/eboot.c
> > @@ -368,6 +368,91 @@ free_handle:
> >  	return status;
> >  }
> >  
> > +#ifdef CONFIG_SNAPSHOT_VERIFICATION
> > +static efi_status_t setup_s4_keys(struct boot_params *params)
> > +{
> > +	struct setup_data *data;
> > +	unsigned long datasize;
> > +	u32 attr;
> > +	struct efi_s4_key *s4key;
> > +	efi_status_t status;
> > +
> > +	data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
> 
> A bit too many casts.

Thanks.
Yes, here is my mistake, I will remove "unsigned long" cast.

> 
> > @@ -1205,6 +1290,10 @@ struct boot_params *efi_main(void *handle, efi_system_table_t *_table,
> >  
> >  	setup_efi_pci(boot_params);
> >  
> > +#ifdef CONFIG_SNAPSHOT_VERIFICATION
> > +	setup_s4_keys(boot_params);
> > +#endif
> > +
> 
> Move ifdef inside the function?

OK, I will define a dummy function for non-verification situation.

> 
> > @@ -729,6 +792,11 @@ void __init efi_init(void)
> >  
> >  	set_bit(EFI_SYSTEM_TABLES, &x86_efi_facility);
> >  
> > +#ifdef CONFIG_SNAPSHOT_VERIFICATION
> > +	/* keep s4 key from setup_data */
> > +	efi_reserve_s4_skey_data();
> > +#endif
> > +
> 
> Here too.
> 

I will also use dummy function here. 


Thanks
Joey Lee