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);

lib/crypto/Kconfig

@@ -82,4 +82,13 @@ config PKCS7_MESSAGE_PARSER
 config PKCS7_VERIFY
 	bool
 
+config MSCODE_PARSER
+	bool "MS authenticode parser"
+	select ASN1_DECODER
+	select ASN1_COMPILER
+	select OID_REGISTRY
+	help
+	  This option provides support for parsing MicroSoft's Authenticode
+	  in pkcs7 message.
+
 endif # ASYMMETRIC_KEY_TYPE

lib/crypto/Makefile

@@ -55,3 +55,15 @@ obj-$(CONFIG_$(SPL_)PKCS7_VERIFY) += pkcs7_verify.o
 
 $(obj)/pkcs7_parser.o: $(obj)/pkcs7.asn1.h
 $(obj)/pkcs7.asn1.o: $(obj)/pkcs7.asn1.c $(obj)/pkcs7.asn1.h
+
+#
+# Signed PE binary-wrapped key handling
+#
+obj-$(CONFIG_$(SPL_)MSCODE_PARSER) += mscode.o
+
+mscode-y := \
+	mscode_parser.o \
+	mscode.asn1.o
+
+$(obj)/mscode_parser.o: $(obj)/mscode.asn1.h $(obj)/mscode.asn1.h
+$(obj)/mscode.asn1.o: $(obj)/mscode.asn1.c $(obj)/mscode.asn1.h

lib/crypto/mscode.asn1

@@ -0,0 +1,28 @@
+--- Microsoft individual code signing data blob parser
+---
+--- Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
+--- Written by David Howells (dhowells@redhat.com)
+---
+--- This program is free software; you can redistribute it and/or
+--- modify it under the terms of the GNU General Public Licence
+--- as published by the Free Software Foundation; either version
+--- 2 of the Licence, or (at your option) any later version.
+---
+
+MSCode ::= SEQUENCE {
+	type			SEQUENCE {
+		contentType	ContentType,
+		parameters	ANY
+	},
+	content			SEQUENCE {
+		digestAlgorithm	DigestAlgorithmIdentifier,
+		digest		OCTET STRING ({ mscode_note_digest })
+	}
+}
+
+ContentType ::= OBJECT IDENTIFIER ({ mscode_note_content_type })
+
+DigestAlgorithmIdentifier ::= SEQUENCE {
+	algorithm   OBJECT IDENTIFIER ({ mscode_note_digest_algo }),
+	parameters  ANY OPTIONAL
+}

lib/crypto/mscode_parser.c

@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Parse a Microsoft Individual Code Signing blob
+ *
+ * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ */
+
+#define pr_fmt(fmt) "MSCODE: "fmt
+#include <linux/kernel.h>
+#ifndef __UBOOT__
+#include <linux/slab.h>
+#endif
+#include <linux/err.h>
+#include <linux/oid_registry.h>
+#include <crypto/pkcs7.h>
+#ifdef __UBOOT__
+#include <crypto/mscode.h>
+#else
+#include "verify_pefile.h"
+#endif
+#include "mscode.asn1.h"
+
+/*
+ * Parse a Microsoft Individual Code Signing blob
+ */
+int mscode_parse(void *_ctx, const void *content_data, size_t data_len,
+		 size_t asn1hdrlen)
+{
+	struct pefile_context *ctx = _ctx;
+
+	content_data -= asn1hdrlen;
+	data_len += asn1hdrlen;
+	pr_devel("Data: %zu [%*ph]\n", data_len, (unsigned)(data_len),
+		 content_data);
+
+	return asn1_ber_decoder(&mscode_decoder, ctx, content_data, data_len);
+}
+
+/*
+ * Check the content type OID
+ */
+int mscode_note_content_type(void *context, size_t hdrlen,
+			     unsigned char tag,
+			     const void *value, size_t vlen)
+{
+	enum OID oid;
+
+	oid = look_up_OID(value, vlen);
+	if (oid == OID__NR) {
+		char buffer[50];
+
+		sprint_oid(value, vlen, buffer, sizeof(buffer));
+		pr_err("Unknown OID: %s\n", buffer);
+		return -EBADMSG;
+	}
+
+	/*
+	 * pesign utility had a bug where it was putting
+	 * OID_msIndividualSPKeyPurpose instead of OID_msPeImageDataObjId
+	 * So allow both OIDs.
+	 */
+	if (oid != OID_msPeImageDataObjId &&
+	    oid != OID_msIndividualSPKeyPurpose) {
+		pr_err("Unexpected content type OID %u\n", oid);
+		return -EBADMSG;
+	}
+
+	return 0;
+}
+
+/*
+ * Note the digest algorithm OID
+ */
+int mscode_note_digest_algo(void *context, size_t hdrlen,
+			    unsigned char tag,
+			    const void *value, size_t vlen)
+{
+	struct pefile_context *ctx = context;
+	char buffer[50];
+	enum OID oid;
+
+	oid = look_up_OID(value, vlen);
+	switch (oid) {
+	case OID_md4:
+		ctx->digest_algo = "md4";
+		break;
+	case OID_md5:
+		ctx->digest_algo = "md5";
+		break;
+	case OID_sha1:
+		ctx->digest_algo = "sha1";
+		break;
+	case OID_sha256:
+		ctx->digest_algo = "sha256";
+		break;
+	case OID_sha384:
+		ctx->digest_algo = "sha384";
+		break;
+	case OID_sha512:
+		ctx->digest_algo = "sha512";
+		break;
+	case OID_sha224:
+		ctx->digest_algo = "sha224";
+		break;
+
+	case OID__NR:
+		sprint_oid(value, vlen, buffer, sizeof(buffer));
+		pr_err("Unknown OID: %s\n", buffer);
+		return -EBADMSG;
+
+	default:
+		pr_err("Unsupported content type: %u\n", oid);
+		return -ENOPKG;
+	}
+
+	return 0;
+}
+
+/*
+ * Note the digest we're guaranteeing with this certificate
+ */
+int mscode_note_digest(void *context, size_t hdrlen,
+		       unsigned char tag,
+		       const void *value, size_t vlen)
+{
+	struct pefile_context *ctx = context;
+
+	ctx->digest = kmemdup(value, vlen, GFP_KERNEL);
+	if (!ctx->digest)
+		return -ENOMEM;
+
+	ctx->digest_len = vlen;
+
+	return 0;
+}