[PATCH v4 03/11] efi_loader: capsule: add back efi_get_public_key_data()

[Masami Hiramatsu]

Hi Simon,

2021年10月15日(金) 9:40 Simon Glass <sjg at chromium.org>:
>
> Hi Takahiro,
>
> On Thu, 7 Oct 2021 at 00:25, AKASHI Takahiro <takahiro.akashi at linaro.org> wrote:
> >
> > The commit 47a25e81d35c ("Revert "efi_capsule: Move signature from DTB to
> > .rodata"") failed to revert the removal of efi_get_public_key_data().
> >
> > Add back this function and move it under lib/efi_loader so that other
> > platforms can utilize it. It is now declared as a weak function so that
> > it can be replaced with a platform-specific implementation.
> >
> > Fixes: 47a25e81d35c ("Revert "efi_capsule: Move signature from DTB to
> >         .rodata"")
> > Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
> > ---
> >  lib/efi_loader/efi_capsule.c | 36 ++++++++++++++++++++++++++++++++++++
> >  1 file changed, 36 insertions(+)
> >
> > diff --git a/lib/efi_loader/efi_capsule.c b/lib/efi_loader/efi_capsule.c
> > index b75e4bcba1a9..44f5da61a9be 100644
> > --- a/lib/efi_loader/efi_capsule.c
> > +++ b/lib/efi_loader/efi_capsule.c
> > @@ -11,15 +11,20 @@
> >  #include <common.h>
> >  #include <efi_loader.h>
> >  #include <efi_variable.h>
> > +#include <env.h>
> > +#include <fdtdec.h>
> >  #include <fs.h>
> >  #include <malloc.h>
> >  #include <mapmem.h>
> >  #include <sort.h>
> > +#include <asm/global_data.h>
> >
> >  #include <crypto/pkcs7.h>
> >  #include <crypto/pkcs7_parser.h>
> >  #include <linux/err.h>
> >
> > +DECLARE_GLOBAL_DATA_PTR;
> > +
> >  const efi_guid_t efi_guid_capsule_report = EFI_CAPSULE_REPORT_GUID;
> >  static const efi_guid_t efi_guid_firmware_management_capsule_id =
> >                 EFI_FIRMWARE_MANAGEMENT_CAPSULE_ID_GUID;
> > @@ -251,6 +256,37 @@ out:
> >  }
> >
> >  #if defined(CONFIG_EFI_CAPSULE_AUTHENTICATE)
> > +int __weak efi_get_public_key_data(void **pkey, efi_uintn_t *pkey_len)
>
> I don't think this should be weak. What other way is there of handling
> this and why would it be platform-specific?

I have a question about the current design of the capsule auth key.
If the platform has its own key-storage, how can the platform use the
platform specific storage? Does such platform load the key from the storage
and generate the dtb node in the platform initialization code? (or
device driver?)

Thank you,


>
> > +{
> > +       const void *fdt_blob = gd->fdt_blob;
> > +       const void *blob;
> > +       const char *cnode_name = "capsule-key";
> > +       const char *snode_name = "signature";
> > +       int sig_node;
> > +       int len;
> > +
> > +       sig_node = fdt_subnode_offset(fdt_blob, 0, snode_name);
> > +       if (sig_node < 0) {
> > +               log_err("Unable to get signature node offset\n");
> > +
> > +               return -FDT_ERR_NOTFOUND;
> > +       }
> > +
> > +       blob = fdt_getprop(fdt_blob, sig_node, cnode_name, &len);
> > +
> > +       if (!blob || len < 0) {
> > +               log_err("Unable to get capsule-key value\n");
> > +               *pkey = NULL;
> > +               *pkey_len = 0;
> > +
> > +               return -FDT_ERR_NOTFOUND;
> > +       }
> > +
> > +       *pkey = (void *)blob;
> > +       *pkey_len = len;
> > +
> > +       return 0;
> > +}
> >
> >  efi_status_t efi_capsule_authenticate(const void *capsule, efi_uintn_t capsule_size,
> >                                       void **image, efi_uintn_t *image_size)
> > --
> > 2.33.0
> >
>
> Regards,
> Simon



--
Masami Hiramatsu