lib: crypto: add mscode_parser

In MS authenticode, pkcs7 should have data in its contentInfo field.
This data is tagged with SpcIndirectData type and, for a signed PE image,
provides a image's message digest as SpcPeImageData.

This parser is used in image authentication to parse the field and
retrieve a message digest.

Imported from linux v5.19-rc, crypto/asymmetric_keys/mscode*.
Checkpatch.pl generates tones of warnings, but those are not fixed
for the sake of maintainability (importing from another source).

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

include/crypto/mscode.h

@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* PE Binary parser bits
+ *
+ * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#include <crypto/pkcs7.h>
+#ifndef __UBOOT__
+#include <crypto/hash_info.h>
+#endif
+
+struct pefile_context {
+#ifndef __UBOOT__
+	unsigned	header_size;
+	unsigned	image_checksum_offset;
+	unsigned	cert_dirent_offset;
+	unsigned	n_data_dirents;
+	unsigned	n_sections;
+	unsigned	certs_size;
+	unsigned	sig_offset;
+	unsigned	sig_len;
+	const struct section_header *secs;
+#endif
+
+	/* PKCS#7 MS Individual Code Signing content */
+	const void	*digest;		/* Digest */
+	unsigned	digest_len;		/* Digest length */
+	const char	*digest_algo;		/* Digest algorithm */
+};
+
+#ifndef __UBOOT__
+#define kenter(FMT, ...)					\
+	pr_devel("==> %s("FMT")\n", __func__, ##__VA_ARGS__)
+#define kleave(FMT, ...) \
+	pr_devel("<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
+#endif
+
+/*
+ * mscode_parser.c
+ */
+extern int mscode_parse(void *_ctx, const void *content_data, size_t data_len,
+			size_t asn1hdrlen);