efi_loader: image_loader: verification for all signatures should pass

A signed image may have multiple signatures in
  - each WIN_CERTIFICATE in authenticode, and/or
  - each SignerInfo in pkcs7 SignedData (of WIN_CERTIFICATE)

In the initial implementation of efi_image_authenticate(), the criteria
of verification check for multiple signatures case is a bit ambiguous
and it may cause inconsistent result.

With this patch, we will make sure that verification check in
efi_image_authenticate() should pass against all the signatures.
The only exception would be
  - the case where a digest algorithm used in signature is not supported by
    U-Boot, or
  - the case where parsing some portion of authenticode has failed
In those cases, we don't know how the signature be handled and should
just ignore them.

Please note that, due to this change, efi_signature_verify_with_sigdb()'s
function prototype will be modified, taking "dbx" as well as "db"
instead of outputing a "certificate." If "dbx" is null, the behavior would
be the exact same as before.
The function's name will be changed to efi_signature_verify() once
current efi_signature_verify() has gone due to further improvement
in intermediate certificates support.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>

1 files changed, 7 insertions, 6 deletions

diff --git a/include/efi_loader.h b/include/efi_loader.h
index fc9344c7428..2f9fb112b34 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -765,14 +765,15 @@ struct efi_signature_store {
 struct x509_certificate;
 struct pkcs7_message;
 
-bool efi_signature_verify_cert(struct x509_certificate *cert,
-			       struct efi_signature_store *dbx);
-bool efi_signature_verify_signers(struct pkcs7_message *msg,
-				  struct efi_signature_store *dbx);
+bool efi_signature_verify_one(struct efi_image_regions *regs,
+			      struct pkcs7_message *msg,
+			      struct efi_signature_store *db);
 bool efi_signature_verify_with_sigdb(struct efi_image_regions *regs,
 				     struct pkcs7_message *msg,
-				  struct efi_signature_store *db,
-				  struct x509_certificate **cert);
+				     struct efi_signature_store *db,
+				     struct efi_signature_store *dbx);
+bool efi_signature_check_signers(struct pkcs7_message *msg,
+				 struct efi_signature_store *dbx);
 
 efi_status_t efi_image_region_add(struct efi_image_regions *regs,
 				  const void *start, const void *end,