pefile: Parse the "Microsoft individual code signing" data blob

The PKCS#7 certificate should contain a "Microsoft individual code signing"
data blob as its signed content.  This blob contains a digest of the signed
content of the PE binary and the OID of the digest algorithm used (typically
SHA256).

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
diff --git a/crypto/asymmetric_keys/Makefile b/crypto/asymmetric_keys/Makefile
index 3e4de52..e47fcd9 100644
--- a/crypto/asymmetric_keys/Makefile
+++ b/crypto/asymmetric_keys/Makefile
@@ -54,4 +54,11 @@
 obj-$(CONFIG_SIGNED_PE_FILE_VERIFICATION) += verify_signed_pefile.o
 
 verify_signed_pefile-y := \
-	verify_pefile.o
+	verify_pefile.o \
+	mscode_parser.o \
+	mscode-asn1.o
+
+$(obj)/mscode_parser.o: $(obj)/mscode-asn1.h $(obj)/mscode-asn1.h
+$(obj)/mscode-asn1.o: $(obj)/mscode-asn1.c $(obj)/mscode-asn1.h
+
+clean-files	+= mscode-asn1.c mscode-asn1.h