efi_loader: signature: fix a size check against revocation list

Since the size check against an entry in efi_search_siglist() is
incorrect, this function will never find out a to-be-matched certificate
and its associated revocation time in the signature list.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
diff --git a/lib/efi_loader/efi_signature.c b/lib/efi_loader/efi_signature.c
index e05c471..cd2df46 100644
--- a/lib/efi_loader/efi_signature.c
+++ b/lib/efi_loader/efi_signature.c
@@ -433,10 +433,11 @@
 		 *	time64_t revocation_time;
 		 * };
 		 */
-		if ((sig_data->size == SHA256_SUM_LEN) &&
-		    !memcmp(sig_data->data, hash, SHA256_SUM_LEN)) {
+		if ((sig_data->size >= SHA256_SUM_LEN + sizeof(time64_t)) &&
+		    !memcmp(sig_data->data, msg, SHA256_SUM_LEN)) {
 			memcpy(revoc_time, sig_data->data + SHA256_SUM_LEN,
 			       sizeof(*revoc_time));
+			EFI_PRINT("revocation time: 0x%llx\n", *revoc_time);
 			found = true;
 			goto out;
 		}