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>

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;
+}