Fixed MTP to work with TWRP

crypto/asymmetric_keys/Kconfig

@@ -0,0 +1,70 @@
+menuconfig ASYMMETRIC_KEY_TYPE
+	tristate "Asymmetric (public-key cryptographic) key type"
+	depends on KEYS
+	help
+	  This option provides support for a key type that holds the data for
+	  the asymmetric keys used for public key cryptographic operations such
+	  as encryption, decryption, signature generation and signature
+	  verification.
+
+if ASYMMETRIC_KEY_TYPE
+
+config ASYMMETRIC_PUBLIC_KEY_SUBTYPE
+	tristate "Asymmetric public-key crypto algorithm subtype"
+	select MPILIB
+	select PUBLIC_KEY_ALGO_RSA
+	select CRYPTO_HASH_INFO
+	help
+	  This option provides support for asymmetric public key type handling.
+	  If signature generation and/or verification are to be used,
+	  appropriate hash algorithms (such as SHA-1) must be available.
+	  ENOPKG will be reported if the requisite algorithm is unavailable.
+
+config PUBLIC_KEY_ALGO_RSA
+	tristate "RSA public-key algorithm"
+	select MPILIB
+	help
+	  This option enables support for the RSA algorithm (PKCS#1, RFC3447).
+
+config X509_CERTIFICATE_PARSER
+	tristate "X.509 certificate parser"
+	depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE
+	select ASN1
+	select OID_REGISTRY
+	help
+	  This option provides support for parsing X.509 format blobs for key
+	  data and provides the ability to instantiate a crypto key from a
+	  public key packet found inside the certificate.
+
+config PKCS7_MESSAGE_PARSER
+	tristate "PKCS#7 message parser"
+	depends on X509_CERTIFICATE_PARSER
+	select ASN1
+	select OID_REGISTRY
+	help
+	  This option provides support for parsing PKCS#7 format messages for
+	  signature data and provides the ability to verify the signature.
+
+config PKCS7_TEST_KEY
+	tristate "PKCS#7 testing key type"
+	depends on PKCS7_MESSAGE_PARSER
+	select SYSTEM_TRUSTED_KEYRING
+	help
+	  This option provides a type of key that can be loaded up from a
+	  PKCS#7 message - provided the message is signed by a trusted key.  If
+	  it is, the PKCS#7 wrapper is discarded and reading the key returns
+	  just the payload.  If it isn't, adding the key will fail with an
+	  error.
+
+	  This is intended for testing the PKCS#7 parser.
+
+config SIGNED_PE_FILE_VERIFICATION
+	bool "Support for PE file signature verification"
+	depends on PKCS7_MESSAGE_PARSER=y
+	select ASN1
+	select OID_REGISTRY
+	help
+	  This option provides support for verifying the signature(s) on a
+	  signed PE binary.
+
+endif # ASYMMETRIC_KEY_TYPE

crypto/asymmetric_keys/Makefile

@@ -0,0 +1,64 @@
+#
+# Makefile for asymmetric cryptographic keys
+#
+
+obj-$(CONFIG_ASYMMETRIC_KEY_TYPE) += asymmetric_keys.o
+
+asymmetric_keys-y := asymmetric_type.o signature.o
+
+obj-$(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += public_key.o
+obj-$(CONFIG_PUBLIC_KEY_ALGO_RSA) += rsa.o
+
+#
+# X.509 Certificate handling
+#
+obj-$(CONFIG_X509_CERTIFICATE_PARSER) += x509_key_parser.o
+x509_key_parser-y := \
+	x509-asn1.o \
+	x509_rsakey-asn1.o \
+	x509_cert_parser.o \
+	x509_public_key.o
+
+$(obj)/x509_cert_parser.o: $(obj)/x509-asn1.h $(obj)/x509_rsakey-asn1.h
+$(obj)/x509-asn1.o: $(obj)/x509-asn1.c $(obj)/x509-asn1.h
+$(obj)/x509_rsakey-asn1.o: $(obj)/x509_rsakey-asn1.c $(obj)/x509_rsakey-asn1.h
+
+clean-files	+= x509-asn1.c x509-asn1.h
+clean-files	+= x509_rsakey-asn1.c x509_rsakey-asn1.h
+
+#
+# PKCS#7 message handling
+#
+obj-$(CONFIG_PKCS7_MESSAGE_PARSER) += pkcs7_message.o
+pkcs7_message-y := \
+	pkcs7-asn1.o \
+	pkcs7_parser.o \
+	pkcs7_trust.o \
+	pkcs7_verify.o
+
+$(obj)/pkcs7_parser.o: $(obj)/pkcs7-asn1.h
+$(obj)/pkcs7-asn1.o: $(obj)/pkcs7-asn1.c $(obj)/pkcs7-asn1.h
+
+clean-files	+= pkcs7-asn1.c pkcs7-asn1.h
+
+#
+# PKCS#7 parser testing key
+#
+obj-$(CONFIG_PKCS7_TEST_KEY) += pkcs7_test_key.o
+pkcs7_test_key-y := \
+	pkcs7_key_type.o
+
+#
+# Signed PE binary-wrapped key handling
+#
+obj-$(CONFIG_SIGNED_PE_FILE_VERIFICATION) += verify_signed_pefile.o
+
+verify_signed_pefile-y := \
+	verify_pefile.o \
+	mscode_parser.o \
+	mscode-asn1.o
+
+$(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

crypto/asymmetric_keys/asymmetric_keys.h

@@ -0,0 +1,18 @@
+/* Internal definitions for asymmetric key type
+ *
+ * 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.
+ */
+
+extern struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id);
+
+static inline
+const struct asymmetric_key_ids *asymmetric_key_ids(const struct key *key)
+{
+	return key->type_data.p[1];
+}

crypto/asymmetric_keys/asymmetric_type.c

@@ -0,0 +1,406 @@
+/* Asymmetric public-key cryptography key type
+ *
+ * See Documentation/security/asymmetric-keys.txt
+ *
+ * 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.
+ */
+#include <keys/asymmetric-subtype.h>
+#include <keys/asymmetric-parser.h>
+#include <linux/seq_file.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/ctype.h>
+#include "asymmetric_keys.h"
+
+MODULE_LICENSE("GPL");
+
+static LIST_HEAD(asymmetric_key_parsers);
+static DECLARE_RWSEM(asymmetric_key_parsers_sem);
+
+/**
+ * asymmetric_key_generate_id: Construct an asymmetric key ID
+ * @val_1: First binary blob
+ * @len_1: Length of first binary blob
+ * @val_2: Second binary blob
+ * @len_2: Length of second binary blob
+ *
+ * Construct an asymmetric key ID from a pair of binary blobs.
+ */
+struct asymmetric_key_id *asymmetric_key_generate_id(const void *val_1,
+						     size_t len_1,
+						     const void *val_2,
+						     size_t len_2)
+{
+	struct asymmetric_key_id *kid;
+
+	kid = kmalloc(sizeof(struct asymmetric_key_id) + len_1 + len_2,
+		      GFP_KERNEL);
+	if (!kid)
+		return ERR_PTR(-ENOMEM);
+	kid->len = len_1 + len_2;
+	memcpy(kid->data, val_1, len_1);
+	memcpy(kid->data + len_1, val_2, len_2);
+	return kid;
+}
+EXPORT_SYMBOL_GPL(asymmetric_key_generate_id);
+
+/**
+ * asymmetric_key_id_same - Return true if two asymmetric keys IDs are the same.
+ * @kid_1, @kid_2: The key IDs to compare
+ */
+bool asymmetric_key_id_same(const struct asymmetric_key_id *kid1,
+			    const struct asymmetric_key_id *kid2)
+{
+	if (!kid1 || !kid2)
+		return false;
+	if (kid1->len != kid2->len)
+		return false;
+	return memcmp(kid1->data, kid2->data, kid1->len) == 0;
+}
+EXPORT_SYMBOL_GPL(asymmetric_key_id_same);
+
+/**
+ * asymmetric_key_id_partial - Return true if two asymmetric keys IDs
+ * partially match
+ * @kid_1, @kid_2: The key IDs to compare
+ */
+bool asymmetric_key_id_partial(const struct asymmetric_key_id *kid1,
+			       const struct asymmetric_key_id *kid2)
+{
+	if (!kid1 || !kid2)
+		return false;
+	if (kid1->len < kid2->len)
+		return false;
+	return memcmp(kid1->data + (kid1->len - kid2->len),
+		      kid2->data, kid2->len) == 0;
+}
+EXPORT_SYMBOL_GPL(asymmetric_key_id_partial);
+
+/**
+ * asymmetric_match_key_ids - Search asymmetric key IDs
+ * @kids: The list of key IDs to check
+ * @match_id: The key ID we're looking for
+ * @match: The match function to use
+ */
+static bool asymmetric_match_key_ids(
+	const struct asymmetric_key_ids *kids,
+	const struct asymmetric_key_id *match_id,
+	bool (*match)(const struct asymmetric_key_id *kid1,
+		      const struct asymmetric_key_id *kid2))
+{
+	int i;
+
+	if (!kids || !match_id)
+		return false;
+	for (i = 0; i < ARRAY_SIZE(kids->id); i++)
+		if (match(kids->id[i], match_id))
+			return true;
+	return false;
+}
+
+/**
+ * asymmetric_key_hex_to_key_id - Convert a hex string into a key ID.
+ * @id: The ID as a hex string.
+ */
+struct asymmetric_key_id *asymmetric_key_hex_to_key_id(const char *id)
+{
+	struct asymmetric_key_id *match_id;
+	size_t hexlen;
+	int ret;
+
+	if (!*id)
+		return ERR_PTR(-EINVAL);
+	hexlen = strlen(id);
+	if (hexlen & 1)
+		return ERR_PTR(-EINVAL);
+
+	match_id = kmalloc(sizeof(struct asymmetric_key_id) + hexlen / 2,
+			   GFP_KERNEL);
+	if (!match_id)
+		return ERR_PTR(-ENOMEM);
+	match_id->len = hexlen / 2;
+	ret = hex2bin(match_id->data, id, hexlen / 2);
+	if (ret < 0) {
+		kfree(match_id);
+		return ERR_PTR(-EINVAL);
+	}
+	return match_id;
+}
+
+/*
+ * Match asymmetric keys by an exact match on an ID.
+ */
+static bool asymmetric_key_cmp(const struct key *key,
+			       const struct key_match_data *match_data)
+{
+	const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
+	const struct asymmetric_key_id *match_id = match_data->preparsed;
+
+	return asymmetric_match_key_ids(kids, match_id,
+					asymmetric_key_id_same);
+}
+
+/*
+ * Match asymmetric keys by a partial match on an IDs.
+ */
+static bool asymmetric_key_cmp_partial(const struct key *key,
+				       const struct key_match_data *match_data)
+{
+	const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
+	const struct asymmetric_key_id *match_id = match_data->preparsed;
+
+	return asymmetric_match_key_ids(kids, match_id,
+					asymmetric_key_id_partial);
+}
+
+/*
+ * Preparse the match criterion.  If we don't set lookup_type and cmp,
+ * the default will be an exact match on the key description.
+ *
+ * There are some specifiers for matching key IDs rather than by the key
+ * description:
+ *
+ *	"id:<id>" - find a key by partial match on any available ID
+ *	"ex:<id>" - find a key by exact match on any available ID
+ *
+ * These have to be searched by iteration rather than by direct lookup because
+ * the key is hashed according to its description.
+ */
+static int asymmetric_key_match_preparse(struct key_match_data *match_data)
+{
+	struct asymmetric_key_id *match_id;
+	const char *spec = match_data->raw_data;
+	const char *id;
+	bool (*cmp)(const struct key *, const struct key_match_data *) =
+		asymmetric_key_cmp;
+
+	if (!spec || !*spec)
+		return -EINVAL;
+	if (spec[0] == 'i' &&
+	    spec[1] == 'd' &&
+	    spec[2] == ':') {
+		id = spec + 3;
+		cmp = asymmetric_key_cmp_partial;
+	} else if (spec[0] == 'e' &&
+		   spec[1] == 'x' &&
+		   spec[2] == ':') {
+		id = spec + 3;
+	} else {
+		goto default_match;
+	}
+
+	match_id = asymmetric_key_hex_to_key_id(id);
+	if (IS_ERR(match_id))
+		return PTR_ERR(match_id);
+
+	match_data->preparsed = match_id;
+	match_data->cmp = cmp;
+	match_data->lookup_type = KEYRING_SEARCH_LOOKUP_ITERATE;
+	return 0;
+
+default_match:
+	return 0;
+}
+
+/*
+ * Free the preparsed the match criterion.
+ */
+static void asymmetric_key_match_free(struct key_match_data *match_data)
+{
+	kfree(match_data->preparsed);
+}
+
+/*
+ * Describe the asymmetric key
+ */
+static void asymmetric_key_describe(const struct key *key, struct seq_file *m)
+{
+	const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
+	const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
+	const struct asymmetric_key_id *kid;
+	const unsigned char *p;
+	int n;
+
+	seq_puts(m, key->description);
+
+	if (subtype) {
+		seq_puts(m, ": ");
+		subtype->describe(key, m);
+
+		if (kids && kids->id[1]) {
+			kid = kids->id[1];
+			seq_putc(m, ' ');
+			n = kid->len;
+			p = kid->data;
+			if (n > 4) {
+				p += n - 4;
+				n = 4;
+			}
+			seq_printf(m, "%*phN", n, p);
+		}
+
+		seq_puts(m, " [");
+		/* put something here to indicate the key's capabilities */
+		seq_putc(m, ']');
+	}
+}
+
+/*
+ * Preparse a asymmetric payload to get format the contents appropriately for the
+ * internal payload to cut down on the number of scans of the data performed.
+ *
+ * We also generate a proposed description from the contents of the key that
+ * can be used to name the key if the user doesn't want to provide one.
+ */
+static int asymmetric_key_preparse(struct key_preparsed_payload *prep)
+{
+	struct asymmetric_key_parser *parser;
+	int ret;
+
+	pr_devel("==>%s()\n", __func__);
+
+	if (prep->datalen == 0)
+		return -EINVAL;
+
+	down_read(&asymmetric_key_parsers_sem);
+
+	ret = -EBADMSG;
+	list_for_each_entry(parser, &asymmetric_key_parsers, link) {
+		pr_debug("Trying parser '%s'\n", parser->name);
+
+		ret = parser->parse(prep);
+		if (ret != -EBADMSG) {
+			pr_debug("Parser recognised the format (ret %d)\n",
+				 ret);
+			break;
+		}
+	}
+
+	up_read(&asymmetric_key_parsers_sem);
+	pr_devel("<==%s() = %d\n", __func__, ret);
+	return ret;
+}
+
+/*
+ * Clean up the preparse data
+ */
+static void asymmetric_key_free_preparse(struct key_preparsed_payload *prep)
+{
+	struct asymmetric_key_subtype *subtype = prep->type_data[0];
+	struct asymmetric_key_ids *kids = prep->type_data[1];
+	int i;
+
+	pr_devel("==>%s()\n", __func__);
+
+	if (subtype) {
+		subtype->destroy(prep->payload[0]);
+		module_put(subtype->owner);
+	}
+	if (kids) {
+		for (i = 0; i < ARRAY_SIZE(kids->id); i++)
+			kfree(kids->id[i]);
+		kfree(kids);
+	}
+	kfree(prep->description);
+}
+
+/*
+ * dispose of the data dangling from the corpse of a asymmetric key
+ */
+static void asymmetric_key_destroy(struct key *key)
+{
+	struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
+	struct asymmetric_key_ids *kids = key->type_data.p[1];
+
+	if (subtype) {
+		subtype->destroy(key->payload.data);
+		module_put(subtype->owner);
+		key->type_data.p[0] = NULL;
+	}
+
+	if (kids) {
+		kfree(kids->id[0]);
+		kfree(kids->id[1]);
+		kfree(kids);
+		key->type_data.p[1] = NULL;
+	}
+}
+
+struct key_type key_type_asymmetric = {
+	.name		= "asymmetric",
+	.preparse	= asymmetric_key_preparse,
+	.free_preparse	= asymmetric_key_free_preparse,
+	.instantiate	= generic_key_instantiate,
+	.match_preparse	= asymmetric_key_match_preparse,
+	.match_free	= asymmetric_key_match_free,
+	.destroy	= asymmetric_key_destroy,
+	.describe	= asymmetric_key_describe,
+};
+EXPORT_SYMBOL_GPL(key_type_asymmetric);
+
+/**
+ * register_asymmetric_key_parser - Register a asymmetric key blob parser
+ * @parser: The parser to register
+ */
+int register_asymmetric_key_parser(struct asymmetric_key_parser *parser)
+{
+	struct asymmetric_key_parser *cursor;
+	int ret;
+
+	down_write(&asymmetric_key_parsers_sem);
+
+	list_for_each_entry(cursor, &asymmetric_key_parsers, link) {
+		if (strcmp(cursor->name, parser->name) == 0) {
+			pr_err("Asymmetric key parser '%s' already registered\n",
+			       parser->name);
+			ret = -EEXIST;
+			goto out;
+		}
+	}
+
+	list_add_tail(&parser->link, &asymmetric_key_parsers);
+
+	pr_notice("Asymmetric key parser '%s' registered\n", parser->name);
+	ret = 0;
+
+out:
+	up_write(&asymmetric_key_parsers_sem);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(register_asymmetric_key_parser);
+
+/**
+ * unregister_asymmetric_key_parser - Unregister a asymmetric key blob parser
+ * @parser: The parser to unregister
+ */
+void unregister_asymmetric_key_parser(struct asymmetric_key_parser *parser)
+{
+	down_write(&asymmetric_key_parsers_sem);
+	list_del(&parser->link);
+	up_write(&asymmetric_key_parsers_sem);
+
+	pr_notice("Asymmetric key parser '%s' unregistered\n", parser->name);
+}
+EXPORT_SYMBOL_GPL(unregister_asymmetric_key_parser);
+
+/*
+ * Module stuff
+ */
+static int __init asymmetric_key_init(void)
+{
+	return register_key_type(&key_type_asymmetric);
+}
+
+static void __exit asymmetric_key_cleanup(void)
+{
+	unregister_key_type(&key_type_asymmetric);
+}
+
+module_init(asymmetric_key_init);
+module_exit(asymmetric_key_cleanup);

crypto/asymmetric_keys/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
+}

crypto/asymmetric_keys/mscode_parser.c

@@ -0,0 +1,126 @@
+/* Parse a Microsoft Individual Code Signing blob
+ *
+ * Copyright (C) 2014 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.
+ */
+
+#define pr_fmt(fmt) "MSCODE: "fmt
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/oid_registry.h>
+#include <crypto/pkcs7.h>
+#include "verify_pefile.h"
+#include "mscode-asn1.h"
+
+/*
+ * Parse a Microsoft Individual Code Signing blob
+ */
+int mscode_parse(struct pefile_context *ctx)
+{
+	const void *content_data;
+	size_t data_len;
+	int ret;
+
+	ret = pkcs7_get_content_data(ctx->pkcs7, &content_data, &data_len, 1);
+
+	if (ret) {
+		pr_debug("PKCS#7 message does not contain data\n");
+		return ret;
+	}
+
+	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 = HASH_ALGO_MD4;
+		break;
+	case OID_md5:
+		ctx->digest_algo = HASH_ALGO_MD5;
+		break;
+	case OID_sha1:
+		ctx->digest_algo = HASH_ALGO_SHA1;
+		break;
+	case OID_sha256:
+		ctx->digest_algo = HASH_ALGO_SHA256;
+		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 = value;
+	ctx->digest_len = vlen;
+	return 0;
+}

crypto/asymmetric_keys/pkcs7.asn1

@@ -0,0 +1,127 @@
+PKCS7ContentInfo ::= SEQUENCE {
+	contentType	ContentType,
+	content		[0] EXPLICIT SignedData OPTIONAL
+}
+
+ContentType ::= OBJECT IDENTIFIER ({ pkcs7_note_OID })
+
+SignedData ::= SEQUENCE {
+	version			INTEGER,
+	digestAlgorithms	DigestAlgorithmIdentifiers,
+	contentInfo		ContentInfo,
+	certificates		CHOICE {
+		certSet		[0] IMPLICIT ExtendedCertificatesAndCertificates,
+		certSequence	[2] IMPLICIT Certificates
+	} OPTIONAL ({ pkcs7_note_certificate_list }),
+	crls CHOICE {
+		crlSet		[1] IMPLICIT CertificateRevocationLists,
+		crlSequence	[3] IMPLICIT CRLSequence
+	} OPTIONAL,
+	signerInfos		SignerInfos
+}
+
+ContentInfo ::= SEQUENCE {
+	contentType	ContentType,
+	content		[0] EXPLICIT Data OPTIONAL
+}
+
+Data ::= ANY ({ pkcs7_note_data })
+
+DigestAlgorithmIdentifiers ::= CHOICE {
+	daSet			SET OF DigestAlgorithmIdentifier,
+	daSequence		SEQUENCE OF DigestAlgorithmIdentifier
+}
+
+DigestAlgorithmIdentifier ::= SEQUENCE {
+	algorithm   OBJECT IDENTIFIER ({ pkcs7_note_OID }),
+	parameters  ANY OPTIONAL
+}
+
+--
+-- Certificates and certificate lists
+--
+ExtendedCertificatesAndCertificates ::= SET OF ExtendedCertificateOrCertificate
+
+ExtendedCertificateOrCertificate ::= CHOICE {
+  certificate		Certificate,				-- X.509
+  extendedCertificate	[0] IMPLICIT ExtendedCertificate	-- PKCS#6
+}
+
+ExtendedCertificate ::= Certificate -- cheating
+
+Certificates ::= SEQUENCE OF Certificate
+
+CertificateRevocationLists ::= SET OF CertificateList
+
+CertificateList ::= SEQUENCE OF Certificate -- This may be defined incorrectly
+
+CRLSequence ::= SEQUENCE OF CertificateList
+
+Certificate ::= ANY ({ pkcs7_extract_cert }) -- X.509
+
+--
+-- Signer information
+--
+SignerInfos ::= CHOICE {
+	siSet		SET OF SignerInfo,
+	siSequence	SEQUENCE OF SignerInfo
+}
+
+SignerInfo ::= SEQUENCE {
+	version			INTEGER,
+	issuerAndSerialNumber	IssuerAndSerialNumber,
+	digestAlgorithm		DigestAlgorithmIdentifier ({ pkcs7_sig_note_digest_algo }),
+	authenticatedAttributes	CHOICE {
+		aaSet		[0] IMPLICIT SetOfAuthenticatedAttribute
+					({ pkcs7_sig_note_set_of_authattrs }),
+		aaSequence	[2] EXPLICIT SEQUENCE OF AuthenticatedAttribute
+			-- Explicit because easier to compute digest on
+			-- sequence of attributes and then reuse encoded
+			-- sequence in aaSequence.
+	} OPTIONAL,
+	digestEncryptionAlgorithm
+				DigestEncryptionAlgorithmIdentifier ({ pkcs7_sig_note_pkey_algo }),
+	encryptedDigest		EncryptedDigest,
+	unauthenticatedAttributes CHOICE {
+		uaSet		[1] IMPLICIT SET OF UnauthenticatedAttribute,
+		uaSequence	[3] IMPLICIT SEQUENCE OF UnauthenticatedAttribute
+	} OPTIONAL
+} ({ pkcs7_note_signed_info })
+
+IssuerAndSerialNumber ::= SEQUENCE {
+	issuer			Name ({ pkcs7_sig_note_issuer }),
+	serialNumber		CertificateSerialNumber ({ pkcs7_sig_note_serial })
+}
+
+CertificateSerialNumber ::= INTEGER
+
+SetOfAuthenticatedAttribute ::= SET OF AuthenticatedAttribute
+
+AuthenticatedAttribute ::= SEQUENCE {
+	type			OBJECT IDENTIFIER ({ pkcs7_note_OID }),
+	values			SET OF ANY ({ pkcs7_sig_note_authenticated_attr })
+}
+
+UnauthenticatedAttribute ::= SEQUENCE {
+	type			OBJECT IDENTIFIER ({ pkcs7_note_OID }),
+	values			SET OF ANY
+}
+
+DigestEncryptionAlgorithmIdentifier ::= SEQUENCE {
+	algorithm		OBJECT IDENTIFIER ({ pkcs7_note_OID }),
+	parameters		ANY OPTIONAL
+}
+
+EncryptedDigest ::= OCTET STRING ({ pkcs7_sig_note_signature })
+
+---
+--- X.500 Name
+---
+Name ::= SEQUENCE OF RelativeDistinguishedName
+
+RelativeDistinguishedName ::= SET OF AttributeValueAssertion
+
+AttributeValueAssertion ::= SEQUENCE {
+	attributeType		OBJECT IDENTIFIER ({ pkcs7_note_OID }),
+	attributeValue		ANY
+}

crypto/asymmetric_keys/pkcs7_key_type.c

@@ -0,0 +1,98 @@
+/* Testing module to load key from trusted PKCS#7 message
+ *
+ * Copyright (C) 2014 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.
+ */
+
+#define pr_fmt(fmt) "PKCS7key: "fmt
+#include <linux/key.h>
+#include <linux/err.h>
+#include <linux/key-type.h>
+#include <crypto/pkcs7.h>
+#include <keys/user-type.h>
+#include <keys/system_keyring.h>
+#include "pkcs7_parser.h"
+
+/*
+ * Preparse a PKCS#7 wrapped and validated data blob.
+ */
+static int pkcs7_preparse(struct key_preparsed_payload *prep)
+{
+	struct pkcs7_message *pkcs7;
+	const void *data, *saved_prep_data;
+	size_t datalen, saved_prep_datalen;
+	bool trusted;
+	int ret;
+
+	kenter("");
+
+	saved_prep_data = prep->data;
+	saved_prep_datalen = prep->datalen;
+	pkcs7 = pkcs7_parse_message(saved_prep_data, saved_prep_datalen);
+	if (IS_ERR(pkcs7)) {
+		ret = PTR_ERR(pkcs7);
+		goto error;
+	}
+
+	ret = pkcs7_verify(pkcs7);
+	if (ret < 0)
+		goto error_free;
+
+	ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
+	if (ret < 0)
+		goto error_free;
+	if (!trusted)
+		pr_warn("PKCS#7 message doesn't chain back to a trusted key\n");
+
+	ret = pkcs7_get_content_data(pkcs7, &data, &datalen, false);
+	if (ret < 0)
+		goto error_free;
+
+	prep->data = data;
+	prep->datalen = datalen;
+	ret = user_preparse(prep);
+	prep->data = saved_prep_data;
+	prep->datalen = saved_prep_datalen;
+
+error_free:
+	pkcs7_free_message(pkcs7);
+error:
+	kleave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * user defined keys take an arbitrary string as the description and an
+ * arbitrary blob of data as the payload
+ */
+static struct key_type key_type_pkcs7 = {
+	.name			= "pkcs7_test",
+	.preparse		= pkcs7_preparse,
+	.free_preparse		= user_free_preparse,
+	.instantiate		= generic_key_instantiate,
+	.revoke			= user_revoke,
+	.destroy		= user_destroy,
+	.describe		= user_describe,
+	.read			= user_read,
+};
+
+/*
+ * Module stuff
+ */
+static int __init pkcs7_key_init(void)
+{
+	return register_key_type(&key_type_pkcs7);
+}
+
+static void __exit pkcs7_key_cleanup(void)
+{
+	unregister_key_type(&key_type_pkcs7);
+}
+
+module_init(pkcs7_key_init);
+module_exit(pkcs7_key_cleanup);

crypto/asymmetric_keys/pkcs7_parser.c

@@ -0,0 +1,417 @@
+/* PKCS#7 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.
+ */
+
+#define pr_fmt(fmt) "PKCS7: "fmt
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/oid_registry.h>
+#include "public_key.h"
+#include "pkcs7_parser.h"
+#include "pkcs7-asn1.h"
+
+struct pkcs7_parse_context {
+	struct pkcs7_message	*msg;		/* Message being constructed */
+	struct pkcs7_signed_info *sinfo;	/* SignedInfo being constructed */
+	struct pkcs7_signed_info **ppsinfo;
+	struct x509_certificate *certs;		/* Certificate cache */
+	struct x509_certificate **ppcerts;
+	unsigned long	data;			/* Start of data */
+	enum OID	last_oid;		/* Last OID encountered */
+	unsigned	x509_index;
+	unsigned	sinfo_index;
+	const void	*raw_serial;
+	unsigned	raw_serial_size;
+	unsigned	raw_issuer_size;
+	const void	*raw_issuer;
+};
+
+/*
+ * Free a signed information block.
+ */
+static void pkcs7_free_signed_info(struct pkcs7_signed_info *sinfo)
+{
+	if (sinfo) {
+		mpi_free(sinfo->sig.mpi[0]);
+		kfree(sinfo->sig.digest);
+		kfree(sinfo->signing_cert_id);
+		kfree(sinfo);
+	}
+}
+
+/**
+ * pkcs7_free_message - Free a PKCS#7 message
+ * @pkcs7: The PKCS#7 message to free
+ */
+void pkcs7_free_message(struct pkcs7_message *pkcs7)
+{
+	struct x509_certificate *cert;
+	struct pkcs7_signed_info *sinfo;
+
+	if (pkcs7) {
+		while (pkcs7->certs) {
+			cert = pkcs7->certs;
+			pkcs7->certs = cert->next;
+			x509_free_certificate(cert);
+		}
+		while (pkcs7->crl) {
+			cert = pkcs7->crl;
+			pkcs7->crl = cert->next;
+			x509_free_certificate(cert);
+		}
+		while (pkcs7->signed_infos) {
+			sinfo = pkcs7->signed_infos;
+			pkcs7->signed_infos = sinfo->next;
+			pkcs7_free_signed_info(sinfo);
+		}
+		kfree(pkcs7);
+	}
+}
+EXPORT_SYMBOL_GPL(pkcs7_free_message);
+
+/**
+ * pkcs7_parse_message - Parse a PKCS#7 message
+ * @data: The raw binary ASN.1 encoded message to be parsed
+ * @datalen: The size of the encoded message
+ */
+struct pkcs7_message *pkcs7_parse_message(const void *data, size_t datalen)
+{
+	struct pkcs7_parse_context *ctx;
+	struct pkcs7_message *msg = ERR_PTR(-ENOMEM);
+	int ret;
+
+	ctx = kzalloc(sizeof(struct pkcs7_parse_context), GFP_KERNEL);
+	if (!ctx)
+		goto out_no_ctx;
+	ctx->msg = kzalloc(sizeof(struct pkcs7_message), GFP_KERNEL);
+	if (!ctx->msg)
+		goto out_no_msg;
+	ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL);
+	if (!ctx->sinfo)
+		goto out_no_sinfo;
+
+	ctx->data = (unsigned long)data;
+	ctx->ppcerts = &ctx->certs;
+	ctx->ppsinfo = &ctx->msg->signed_infos;
+
+	/* Attempt to decode the signature */
+	ret = asn1_ber_decoder(&pkcs7_decoder, ctx, data, datalen);
+	if (ret < 0) {
+		msg = ERR_PTR(ret);
+		goto out;
+	}
+
+	msg = ctx->msg;
+	ctx->msg = NULL;
+
+out:
+	while (ctx->certs) {
+		struct x509_certificate *cert = ctx->certs;
+		ctx->certs = cert->next;
+		x509_free_certificate(cert);
+	}
+	pkcs7_free_signed_info(ctx->sinfo);
+out_no_sinfo:
+	pkcs7_free_message(ctx->msg);
+out_no_msg:
+	kfree(ctx);
+out_no_ctx:
+	return msg;
+}
+EXPORT_SYMBOL_GPL(pkcs7_parse_message);
+
+/**
+ * pkcs7_get_content_data - Get access to the PKCS#7 content
+ * @pkcs7: The preparsed PKCS#7 message to access
+ * @_data: Place to return a pointer to the data
+ * @_data_len: Place to return the data length
+ * @want_wrapper: True if the ASN.1 object header should be included in the data
+ *
+ * Get access to the data content of the PKCS#7 message, including, optionally,
+ * the header of the ASN.1 object that contains it.  Returns -ENODATA if the
+ * data object was missing from the message.
+ */
+int pkcs7_get_content_data(const struct pkcs7_message *pkcs7,
+			   const void **_data, size_t *_data_len,
+			   bool want_wrapper)
+{
+	size_t wrapper;
+
+	if (!pkcs7->data)
+		return -ENODATA;
+
+	wrapper = want_wrapper ? pkcs7->data_hdrlen : 0;
+	*_data = pkcs7->data - wrapper;
+	*_data_len = pkcs7->data_len + wrapper;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pkcs7_get_content_data);
+
+/*
+ * Note an OID when we find one for later processing when we know how
+ * to interpret it.
+ */
+int pkcs7_note_OID(void *context, size_t hdrlen,
+		   unsigned char tag,
+		   const void *value, size_t vlen)
+{
+	struct pkcs7_parse_context *ctx = context;
+
+	ctx->last_oid = look_up_OID(value, vlen);
+	if (ctx->last_oid == OID__NR) {
+		char buffer[50];
+		sprint_oid(value, vlen, buffer, sizeof(buffer));
+		printk("PKCS7: Unknown OID: [%lu] %s\n",
+		       (unsigned long)value - ctx->data, buffer);
+	}
+	return 0;
+}
+
+/*
+ * Note the digest algorithm for the signature.
+ */
+int pkcs7_sig_note_digest_algo(void *context, size_t hdrlen,
+			       unsigned char tag,
+			       const void *value, size_t vlen)
+{
+	struct pkcs7_parse_context *ctx = context;
+
+	switch (ctx->last_oid) {
+	case OID_md4:
+		ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_MD4;
+		break;
+	case OID_md5:
+		ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_MD5;
+		break;
+	case OID_sha1:
+		ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_SHA1;
+		break;
+	case OID_sha256:
+		ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_SHA256;
+		break;
+	default:
+		printk("Unsupported digest algo: %u\n", ctx->last_oid);
+		return -ENOPKG;
+	}
+	return 0;
+}
+
+/*
+ * Note the public key algorithm for the signature.
+ */
+int pkcs7_sig_note_pkey_algo(void *context, size_t hdrlen,
+			     unsigned char tag,
+			     const void *value, size_t vlen)
+{
+	struct pkcs7_parse_context *ctx = context;
+
+	switch (ctx->last_oid) {
+	case OID_rsaEncryption:
+		ctx->sinfo->sig.pkey_algo = PKEY_ALGO_RSA;
+		break;
+	default:
+		printk("Unsupported pkey algo: %u\n", ctx->last_oid);
+		return -ENOPKG;
+	}
+	return 0;
+}
+
+/*
+ * Extract a certificate and store it in the context.
+ */
+int pkcs7_extract_cert(void *context, size_t hdrlen,
+		       unsigned char tag,
+		       const void *value, size_t vlen)
+{
+	struct pkcs7_parse_context *ctx = context;
+	struct x509_certificate *x509;
+
+	if (tag != ((ASN1_UNIV << 6) | ASN1_CONS_BIT | ASN1_SEQ)) {
+		pr_debug("Cert began with tag %02x at %lu\n",
+			 tag, (unsigned long)ctx - ctx->data);
+		return -EBADMSG;
+	}
+
+	/* We have to correct for the header so that the X.509 parser can start
+	 * from the beginning.  Note that since X.509 stipulates DER, there
+	 * probably shouldn't be an EOC trailer - but it is in PKCS#7 (which
+	 * stipulates BER).
+	 */
+	value -= hdrlen;
+	vlen += hdrlen;
+
+	if (((u8*)value)[1] == 0x80)
+		vlen += 2; /* Indefinite length - there should be an EOC */
+
+	x509 = x509_cert_parse(value, vlen);
+	if (IS_ERR(x509))
+		return PTR_ERR(x509);
+
+	x509->index = ++ctx->x509_index;
+	pr_debug("Got cert %u for %s\n", x509->index, x509->subject);
+	pr_debug("- fingerprint %*phN\n", x509->id->len, x509->id->data);
+
+	*ctx->ppcerts = x509;
+	ctx->ppcerts = &x509->next;
+	return 0;
+}
+
+/*
+ * Save the certificate list
+ */
+int pkcs7_note_certificate_list(void *context, size_t hdrlen,
+				unsigned char tag,
+				const void *value, size_t vlen)
+{
+	struct pkcs7_parse_context *ctx = context;
+
+	pr_devel("Got cert list (%02x)\n", tag);
+
+	*ctx->ppcerts = ctx->msg->certs;
+	ctx->msg->certs = ctx->certs;
+	ctx->certs = NULL;
+	ctx->ppcerts = &ctx->certs;
+	return 0;
+}
+
+/*
+ * Extract the data from the message and store that and its content type OID in
+ * the context.
+ */
+int pkcs7_note_data(void *context, size_t hdrlen,
+		    unsigned char tag,
+		    const void *value, size_t vlen)
+{
+	struct pkcs7_parse_context *ctx = context;
+
+	pr_debug("Got data\n");
+
+	ctx->msg->data = value;
+	ctx->msg->data_len = vlen;
+	ctx->msg->data_hdrlen = hdrlen;
+	ctx->msg->data_type = ctx->last_oid;
+	return 0;
+}
+
+/*
+ * Parse authenticated attributes
+ */
+int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen,
+				      unsigned char tag,
+				      const void *value, size_t vlen)
+{
+	struct pkcs7_parse_context *ctx = context;
+
+	pr_devel("AuthAttr: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value);
+
+	switch (ctx->last_oid) {
+	case OID_messageDigest:
+		if (tag != ASN1_OTS)
+			return -EBADMSG;
+		ctx->sinfo->msgdigest = value;
+		ctx->sinfo->msgdigest_len = vlen;
+		return 0;
+	default:
+		return 0;
+	}
+}
+
+/*
+ * Note the set of auth attributes for digestion purposes [RFC2315 9.3]
+ */
+int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen,
+				    unsigned char tag,
+				    const void *value, size_t vlen)
+{
+	struct pkcs7_parse_context *ctx = context;
+
+	/* We need to switch the 'CONT 0' to a 'SET OF' when we digest */
+	ctx->sinfo->authattrs = value - (hdrlen - 1);
+	ctx->sinfo->authattrs_len = vlen + (hdrlen - 1);
+	return 0;
+}
+
+/*
+ * Note the issuing certificate serial number
+ */
+int pkcs7_sig_note_serial(void *context, size_t hdrlen,
+			  unsigned char tag,
+			  const void *value, size_t vlen)
+{
+	struct pkcs7_parse_context *ctx = context;
+	ctx->raw_serial = value;
+	ctx->raw_serial_size = vlen;
+	return 0;
+}
+
+/*
+ * Note the issuer's name
+ */
+int pkcs7_sig_note_issuer(void *context, size_t hdrlen,
+			  unsigned char tag,
+			  const void *value, size_t vlen)
+{
+	struct pkcs7_parse_context *ctx = context;
+	ctx->raw_issuer = value;
+	ctx->raw_issuer_size = vlen;
+	return 0;
+}
+
+/*
+ * Note the signature data
+ */
+int pkcs7_sig_note_signature(void *context, size_t hdrlen,
+			     unsigned char tag,
+			     const void *value, size_t vlen)
+{
+	struct pkcs7_parse_context *ctx = context;
+	MPI mpi;
+
+	BUG_ON(ctx->sinfo->sig.pkey_algo != PKEY_ALGO_RSA);
+
+	mpi = mpi_read_raw_data(value, vlen);
+	if (!mpi)
+		return -ENOMEM;
+
+	ctx->sinfo->sig.mpi[0] = mpi;
+	ctx->sinfo->sig.nr_mpi = 1;
+	return 0;
+}
+
+/*
+ * Note a signature information block
+ */
+int pkcs7_note_signed_info(void *context, size_t hdrlen,
+			   unsigned char tag,
+			   const void *value, size_t vlen)
+{
+	struct pkcs7_parse_context *ctx = context;
+	struct pkcs7_signed_info *sinfo = ctx->sinfo;
+	struct asymmetric_key_id *kid;
+
+	/* Generate cert issuer + serial number key ID */
+	kid = asymmetric_key_generate_id(ctx->raw_serial,
+					 ctx->raw_serial_size,
+					 ctx->raw_issuer,
+					 ctx->raw_issuer_size);
+	if (IS_ERR(kid))
+		return PTR_ERR(kid);
+
+	sinfo->signing_cert_id = kid;
+	sinfo->index = ++ctx->sinfo_index;
+	*ctx->ppsinfo = sinfo;
+	ctx->ppsinfo = &sinfo->next;
+	ctx->sinfo = kzalloc(sizeof(struct pkcs7_signed_info), GFP_KERNEL);
+	if (!ctx->sinfo)
+		return -ENOMEM;
+	return 0;
+}

crypto/asymmetric_keys/pkcs7_parser.h

@@ -0,0 +1,59 @@
+/* PKCS#7 crypto data parser internal definitions
+ *
+ * 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.
+ */
+
+#include <linux/oid_registry.h>
+#include <crypto/pkcs7.h>
+#include "x509_parser.h"
+
+#define kenter(FMT, ...) \
+	pr_devel("==> %s("FMT")\n", __func__, ##__VA_ARGS__)
+#define kleave(FMT, ...) \
+	pr_devel("<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
+
+struct pkcs7_signed_info {
+	struct pkcs7_signed_info *next;
+	struct x509_certificate *signer; /* Signing certificate (in msg->certs) */
+	unsigned index;
+	bool trusted;
+	bool unsupported_crypto;	/* T if not usable due to missing crypto */
+
+	/* Message digest - the digest of the Content Data (or NULL) */
+	const void	*msgdigest;
+	unsigned	msgdigest_len;
+
+	/* Authenticated Attribute data (or NULL) */
+	unsigned	authattrs_len;
+	const void	*authattrs;
+
+	/* Issuing cert serial number and issuer's name */
+	struct asymmetric_key_id *signing_cert_id;
+
+	/* Message signature.
+	 *
+	 * This contains the generated digest of _either_ the Content Data or
+	 * the Authenticated Attributes [RFC2315 9.3].  If the latter, one of
+	 * the attributes contains the digest of the the Content Data within
+	 * it.
+	 */
+	struct public_key_signature sig;
+};
+
+struct pkcs7_message {
+	struct x509_certificate *certs;	/* Certificate list */
+	struct x509_certificate *crl;	/* Revocation list */
+	struct pkcs7_signed_info *signed_infos;
+
+	/* Content Data (or NULL) */
+	enum OID	data_type;	/* Type of Data */
+	size_t		data_len;	/* Length of Data */
+	size_t		data_hdrlen;	/* Length of Data ASN.1 header */
+	const void	*data;		/* Content Data (or 0) */
+};

crypto/asymmetric_keys/pkcs7_trust.c

@@ -0,0 +1,200 @@
+/* Validate the trust chain of a PKCS#7 message.
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "PKCS7: "fmt
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/asn1.h>
+#include <linux/key.h>
+#include <keys/asymmetric-type.h>
+#include "public_key.h"
+#include "pkcs7_parser.h"
+
+/**
+ * Check the trust on one PKCS#7 SignedInfo block.
+ */
+static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7,
+				    struct pkcs7_signed_info *sinfo,
+				    struct key *trust_keyring)
+{
+	struct public_key_signature *sig = &sinfo->sig;
+	struct x509_certificate *x509, *last = NULL, *p;
+	struct key *key;
+	bool trusted;
+	int ret;
+
+	kenter(",%u,", sinfo->index);
+
+	if (sinfo->unsupported_crypto) {
+		kleave(" = -ENOPKG [cached]");
+		return -ENOPKG;
+	}
+
+	for (x509 = sinfo->signer; x509; x509 = x509->signer) {
+		if (x509->seen) {
+			if (x509->verified) {
+				trusted = x509->trusted;
+				goto verified;
+			}
+			kleave(" = -ENOKEY [cached]");
+			return -ENOKEY;
+		}
+		x509->seen = true;
+
+		/* Look to see if this certificate is present in the trusted
+		 * keys.
+		 */
+		key = x509_request_asymmetric_key(trust_keyring, x509->id,
+						  false);
+		if (!IS_ERR(key)) {
+			/* One of the X.509 certificates in the PKCS#7 message
+			 * is apparently the same as one we already trust.
+			 * Verify that the trusted variant can also validate
+			 * the signature on the descendant.
+			 */
+			pr_devel("sinfo %u: Cert %u as key %x\n",
+				 sinfo->index, x509->index, key_serial(key));
+			goto matched;
+		}
+		if (key == ERR_PTR(-ENOMEM))
+			return -ENOMEM;
+
+		 /* Self-signed certificates form roots of their own, and if we
+		  * don't know them, then we can't accept them.
+		  */
+		if (x509->next == x509) {
+			kleave(" = -ENOKEY [unknown self-signed]");
+			return -ENOKEY;
+		}
+
+		might_sleep();
+		last = x509;
+		sig = &last->sig;
+	}
+
+	/* No match - see if the root certificate has a signer amongst the
+	 * trusted keys.
+	 */
+	if (last && last->authority) {
+		key = x509_request_asymmetric_key(trust_keyring, last->authority,
+						  false);
+		if (!IS_ERR(key)) {
+			x509 = last;
+			pr_devel("sinfo %u: Root cert %u signer is key %x\n",
+				 sinfo->index, x509->index, key_serial(key));
+			goto matched;
+		}
+		if (PTR_ERR(key) != -ENOKEY)
+			return PTR_ERR(key);
+	}
+
+	/* As a last resort, see if we have a trusted public key that matches
+	 * the signed info directly.
+	 */
+	key = x509_request_asymmetric_key(trust_keyring,
+					  sinfo->signing_cert_id,
+					  false);
+	if (!IS_ERR(key)) {
+		pr_devel("sinfo %u: Direct signer is key %x\n",
+			 sinfo->index, key_serial(key));
+		x509 = NULL;
+		goto matched;
+	}
+	if (PTR_ERR(key) != -ENOKEY)
+		return PTR_ERR(key);
+
+	kleave(" = -ENOKEY [no backref]");
+	return -ENOKEY;
+
+matched:
+	ret = verify_signature(key, sig);
+	trusted = test_bit(KEY_FLAG_TRUSTED, &key->flags);
+	key_put(key);
+	if (ret < 0) {
+		if (ret == -ENOMEM)
+			return ret;
+		kleave(" = -EKEYREJECTED [verify %d]", ret);
+		return -EKEYREJECTED;
+	}
+
+verified:
+	if (x509) {
+		x509->verified = true;
+		for (p = sinfo->signer; p != x509; p = p->signer) {
+			p->verified = true;
+			p->trusted = trusted;
+		}
+	}
+	sinfo->trusted = trusted;
+	kleave(" = 0");
+	return 0;
+}
+
+/**
+ * pkcs7_validate_trust - Validate PKCS#7 trust chain
+ * @pkcs7: The PKCS#7 certificate to validate
+ * @trust_keyring: Signing certificates to use as starting points
+ * @_trusted: Set to true if trustworth, false otherwise
+ *
+ * Validate that the certificate chain inside the PKCS#7 message intersects
+ * keys we already know and trust.
+ *
+ * Returns, in order of descending priority:
+ *
+ *  (*) -EKEYREJECTED if a signature failed to match for which we have a valid
+ *	key, or:
+ *
+ *  (*) 0 if at least one signature chain intersects with the keys in the trust
+ *	keyring, or:
+ *
+ *  (*) -ENOPKG if a suitable crypto module couldn't be found for a check on a
+ *	chain.
+ *
+ *  (*) -ENOKEY if we couldn't find a match for any of the signature chains in
+ *	the message.
+ *
+ * May also return -ENOMEM.
+ */
+int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
+			 struct key *trust_keyring,
+			 bool *_trusted)
+{
+	struct pkcs7_signed_info *sinfo;
+	struct x509_certificate *p;
+	int cached_ret = -ENOKEY;
+	int ret;
+
+	for (p = pkcs7->certs; p; p = p->next)
+		p->seen = false;
+
+	for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) {
+		ret = pkcs7_validate_trust_one(pkcs7, sinfo, trust_keyring);
+		switch (ret) {
+		case -ENOKEY:
+			continue;
+		case -ENOPKG:
+			if (cached_ret == -ENOKEY)
+				cached_ret = -ENOPKG;
+			continue;
+		case 0:
+			*_trusted |= sinfo->trusted;
+			cached_ret = 0;
+			continue;
+		default:
+			return ret;
+		}
+	}
+
+	return cached_ret;
+}
+EXPORT_SYMBOL_GPL(pkcs7_validate_trust);

crypto/asymmetric_keys/pkcs7_verify.c

@@ -0,0 +1,361 @@
+/* Verify the signature on a PKCS#7 message.
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "PKCS7: "fmt
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/asn1.h>
+#include <crypto/hash.h>
+#include "public_key.h"
+#include "pkcs7_parser.h"
+
+/*
+ * Digest the relevant parts of the PKCS#7 data
+ */
+static int pkcs7_digest(struct pkcs7_message *pkcs7,
+			struct pkcs7_signed_info *sinfo)
+{
+	struct crypto_shash *tfm;
+	struct shash_desc *desc;
+	size_t digest_size, desc_size;
+	void *digest;
+	int ret;
+
+	kenter(",%u,%u", sinfo->index, sinfo->sig.pkey_hash_algo);
+
+	if (sinfo->sig.pkey_hash_algo >= PKEY_HASH__LAST ||
+	    !hash_algo_name[sinfo->sig.pkey_hash_algo])
+		return -ENOPKG;
+
+	/* Allocate the hashing algorithm we're going to need and find out how
+	 * big the hash operational data will be.
+	 */
+	tfm = crypto_alloc_shash(hash_algo_name[sinfo->sig.pkey_hash_algo],
+				 0, 0);
+	if (IS_ERR(tfm))
+		return (PTR_ERR(tfm) == -ENOENT) ? -ENOPKG : PTR_ERR(tfm);
+
+	desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
+	sinfo->sig.digest_size = digest_size = crypto_shash_digestsize(tfm);
+
+	ret = -ENOMEM;
+	digest = kzalloc(digest_size + desc_size, GFP_KERNEL);
+	if (!digest)
+		goto error_no_desc;
+
+	desc = digest + digest_size;
+	desc->tfm   = tfm;
+	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	/* Digest the message [RFC2315 9.3] */
+	ret = crypto_shash_init(desc);
+	if (ret < 0)
+		goto error;
+	ret = crypto_shash_finup(desc, pkcs7->data, pkcs7->data_len, digest);
+	if (ret < 0)
+		goto error;
+	pr_devel("MsgDigest = [%*ph]\n", 8, digest);
+
+	/* However, if there are authenticated attributes, there must be a
+	 * message digest attribute amongst them which corresponds to the
+	 * digest we just calculated.
+	 */
+	if (sinfo->msgdigest) {
+		u8 tag;
+
+		if (sinfo->msgdigest_len != sinfo->sig.digest_size) {
+			pr_debug("Sig %u: Invalid digest size (%u)\n",
+				 sinfo->index, sinfo->msgdigest_len);
+			ret = -EBADMSG;
+			goto error;
+		}
+
+		if (memcmp(digest, sinfo->msgdigest, sinfo->msgdigest_len) != 0) {
+			pr_debug("Sig %u: Message digest doesn't match\n",
+				 sinfo->index);
+			ret = -EKEYREJECTED;
+			goto error;
+		}
+
+		/* We then calculate anew, using the authenticated attributes
+		 * as the contents of the digest instead.  Note that we need to
+		 * convert the attributes from a CONT.0 into a SET before we
+		 * hash it.
+		 */
+		memset(digest, 0, sinfo->sig.digest_size);
+
+		ret = crypto_shash_init(desc);
+		if (ret < 0)
+			goto error;
+		tag = ASN1_CONS_BIT | ASN1_SET;
+		ret = crypto_shash_update(desc, &tag, 1);
+		if (ret < 0)
+			goto error;
+		ret = crypto_shash_finup(desc, sinfo->authattrs,
+					 sinfo->authattrs_len, digest);
+		if (ret < 0)
+			goto error;
+		pr_devel("AADigest = [%*ph]\n", 8, digest);
+	}
+
+	sinfo->sig.digest = digest;
+	digest = NULL;
+
+error:
+	kfree(digest);
+error_no_desc:
+	crypto_free_shash(tfm);
+	kleave(" = %d", ret);
+	return ret;
+}
+
+/*
+ * Find the key (X.509 certificate) to use to verify a PKCS#7 message.  PKCS#7
+ * uses the issuer's name and the issuing certificate serial number for
+ * matching purposes.  These must match the certificate issuer's name (not
+ * subject's name) and the certificate serial number [RFC 2315 6.7].
+ */
+static int pkcs7_find_key(struct pkcs7_message *pkcs7,
+			  struct pkcs7_signed_info *sinfo)
+{
+	struct x509_certificate *x509;
+	unsigned certix = 1;
+
+	kenter("%u", sinfo->index);
+
+	for (x509 = pkcs7->certs; x509; x509 = x509->next, certix++) {
+		/* I'm _assuming_ that the generator of the PKCS#7 message will
+		 * encode the fields from the X.509 cert in the same way in the
+		 * PKCS#7 message - but I can't be 100% sure of that.  It's
+		 * possible this will need element-by-element comparison.
+		 */
+		if (!asymmetric_key_id_same(x509->id, sinfo->signing_cert_id))
+			continue;
+		pr_devel("Sig %u: Found cert serial match X.509[%u]\n",
+			 sinfo->index, certix);
+
+		if (x509->pub->pkey_algo != sinfo->sig.pkey_algo) {
+			pr_warn("Sig %u: X.509 algo and PKCS#7 sig algo don't match\n",
+				sinfo->index);
+			continue;
+		}
+
+		sinfo->signer = x509;
+		return 0;
+	}
+
+	/* The relevant X.509 cert isn't found here, but it might be found in
+	 * the trust keyring.
+	 */
+	pr_debug("Sig %u: Issuing X.509 cert not found (#%*phN)\n",
+		 sinfo->index,
+		 sinfo->signing_cert_id->len, sinfo->signing_cert_id->data);
+	return 0;
+}
+
+/*
+ * Verify the internal certificate chain as best we can.
+ */
+static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7,
+				  struct pkcs7_signed_info *sinfo)
+{
+	struct x509_certificate *x509 = sinfo->signer, *p;
+	int ret;
+
+	kenter("");
+
+	for (p = pkcs7->certs; p; p = p->next)
+		p->seen = false;
+
+	for (;;) {
+		pr_debug("verify %s: %*phN\n",
+			 x509->subject,
+			 x509->raw_serial_size, x509->raw_serial);
+		x509->seen = true;
+		ret = x509_get_sig_params(x509);
+		if (ret < 0)
+			goto maybe_missing_crypto_in_x509;
+
+		pr_debug("- issuer %s\n", x509->issuer);
+		if (x509->authority)
+			pr_debug("- authkeyid %*phN\n",
+				 x509->authority->len, x509->authority->data);
+
+		if (!x509->authority ||
+		    strcmp(x509->subject, x509->issuer) == 0) {
+			/* If there's no authority certificate specified, then
+			 * the certificate must be self-signed and is the root
+			 * of the chain.  Likewise if the cert is its own
+			 * authority.
+			 */
+			pr_debug("- no auth?\n");
+			if (x509->raw_subject_size != x509->raw_issuer_size ||
+			    memcmp(x509->raw_subject, x509->raw_issuer,
+				   x509->raw_issuer_size) != 0)
+				return 0;
+
+			ret = x509_check_signature(x509->pub, x509);
+			if (ret < 0)
+				goto maybe_missing_crypto_in_x509;
+			x509->signer = x509;
+			pr_debug("- self-signed\n");
+			return 0;
+		}
+
+		/* Look through the X.509 certificates in the PKCS#7 message's
+		 * list to see if the next one is there.
+		 */
+		pr_debug("- want %*phN\n",
+			 x509->authority->len, x509->authority->data);
+		for (p = pkcs7->certs; p; p = p->next) {
+			if (!p->skid)
+				continue;
+			pr_debug("- cmp [%u] %*phN\n",
+				 p->index, p->skid->len, p->skid->data);
+			if (asymmetric_key_id_same(p->skid, x509->authority))
+				goto found_issuer;
+		}
+
+		/* We didn't find the root of this chain */
+		pr_debug("- top\n");
+		return 0;
+
+	found_issuer:
+		pr_debug("- subject %s\n", p->subject);
+		if (p->seen) {
+			pr_warn("Sig %u: X.509 chain contains loop\n",
+				sinfo->index);
+			return 0;
+		}
+		ret = x509_check_signature(p->pub, x509);
+		if (ret < 0)
+			return ret;
+		x509->signer = p;
+		if (x509 == p) {
+			pr_debug("- self-signed\n");
+			return 0;
+		}
+		x509 = p;
+		might_sleep();
+	}
+
+maybe_missing_crypto_in_x509:
+	/* Just prune the certificate chain at this point if we lack some
+	 * crypto module to go further.  Note, however, we don't want to set
+	 * sinfo->missing_crypto as the signed info block may still be
+	 * validatable against an X.509 cert lower in the chain that we have a
+	 * trusted copy of.
+	 */
+	if (ret == -ENOPKG)
+		return 0;
+	return ret;
+}
+
+/*
+ * Verify one signed information block from a PKCS#7 message.
+ */
+static int pkcs7_verify_one(struct pkcs7_message *pkcs7,
+			    struct pkcs7_signed_info *sinfo)
+{
+	int ret;
+
+	kenter(",%u", sinfo->index);
+
+	/* First of all, digest the data in the PKCS#7 message and the
+	 * signed information block
+	 */
+	ret = pkcs7_digest(pkcs7, sinfo);
+	if (ret < 0)
+		return ret;
+
+	/* Find the key for the signature if there is one */
+	ret = pkcs7_find_key(pkcs7, sinfo);
+	if (ret < 0)
+		return ret;
+
+	if (!sinfo->signer)
+		return 0;
+
+	pr_devel("Using X.509[%u] for sig %u\n",
+		 sinfo->signer->index, sinfo->index);
+
+	/* Verify the PKCS#7 binary against the key */
+	ret = public_key_verify_signature(sinfo->signer->pub, &sinfo->sig);
+	if (ret < 0)
+		return ret;
+
+	pr_devel("Verified signature %u\n", sinfo->index);
+
+	/* Verify the internal certificate chain */
+	return pkcs7_verify_sig_chain(pkcs7, sinfo);
+}
+
+/**
+ * pkcs7_verify - Verify a PKCS#7 message
+ * @pkcs7: The PKCS#7 message to be verified
+ *
+ * Verify a PKCS#7 message is internally consistent - that is, the data digest
+ * matches the digest in the AuthAttrs and any signature in the message or one
+ * of the X.509 certificates it carries that matches another X.509 cert in the
+ * message can be verified.
+ *
+ * This does not look to match the contents of the PKCS#7 message against any
+ * external public keys.
+ *
+ * Returns, in order of descending priority:
+ *
+ *  (*) -EKEYREJECTED if a signature failed to match for which we found an
+ *	appropriate X.509 certificate, or:
+ *
+ *  (*) -EBADMSG if some part of the message was invalid, or:
+ *
+ *  (*) -ENOPKG if none of the signature chains are verifiable because suitable
+ *	crypto modules couldn't be found, or:
+ *
+ *  (*) 0 if all the signature chains that don't incur -ENOPKG can be verified
+ *	(note that a signature chain may be of zero length), or:
+ */
+int pkcs7_verify(struct pkcs7_message *pkcs7)
+{
+	struct pkcs7_signed_info *sinfo;
+	struct x509_certificate *x509;
+	int enopkg = -ENOPKG;
+	int ret, n;
+
+	kenter("");
+
+	for (n = 0, x509 = pkcs7->certs; x509; x509 = x509->next, n++) {
+		ret = x509_get_sig_params(x509);
+		if (ret < 0)
+			return ret;
+		pr_debug("X.509[%u] %*phN\n",
+			 n, x509->authority->len, x509->authority->data);
+	}
+
+	for (sinfo = pkcs7->signed_infos; sinfo; sinfo = sinfo->next) {
+		ret = pkcs7_verify_one(pkcs7, sinfo);
+		if (ret < 0) {
+			if (ret == -ENOPKG) {
+				sinfo->unsupported_crypto = true;
+				continue;
+			}
+			kleave(" = %d", ret);
+			return ret;
+		}
+		enopkg = 0;
+	}
+
+	kleave(" = %d", enopkg);
+	return enopkg;
+}
+EXPORT_SYMBOL_GPL(pkcs7_verify);

crypto/asymmetric_keys/public_key.c

@@ -0,0 +1,129 @@
+/* In-software asymmetric public-key crypto subtype
+ *
+ * See Documentation/crypto/asymmetric-keys.txt
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "PKEY: "fmt
+#include <linux/module.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <keys/asymmetric-subtype.h>
+#include "public_key.h"
+
+MODULE_LICENSE("GPL");
+
+const char *const pkey_algo_name[PKEY_ALGO__LAST] = {
+	[PKEY_ALGO_DSA]		= "DSA",
+	[PKEY_ALGO_RSA]		= "RSA",
+};
+EXPORT_SYMBOL_GPL(pkey_algo_name);
+
+const struct public_key_algorithm *pkey_algo[PKEY_ALGO__LAST] = {
+#if defined(CONFIG_PUBLIC_KEY_ALGO_RSA) || \
+	defined(CONFIG_PUBLIC_KEY_ALGO_RSA_MODULE)
+	[PKEY_ALGO_RSA]		= &RSA_public_key_algorithm,
+#endif
+};
+EXPORT_SYMBOL_GPL(pkey_algo);
+
+const char *const pkey_id_type_name[PKEY_ID_TYPE__LAST] = {
+	[PKEY_ID_PGP]		= "PGP",
+	[PKEY_ID_X509]		= "X509",
+};
+EXPORT_SYMBOL_GPL(pkey_id_type_name);
+
+/*
+ * Provide a part of a description of the key for /proc/keys.
+ */
+static void public_key_describe(const struct key *asymmetric_key,
+				struct seq_file *m)
+{
+	struct public_key *key = asymmetric_key->payload.data;
+
+	if (key)
+		seq_printf(m, "%s.%s",
+			   pkey_id_type_name[key->id_type], key->algo->name);
+}
+
+/*
+ * Destroy a public key algorithm key.
+ */
+void public_key_destroy(void *payload)
+{
+	struct public_key *key = payload;
+	int i;
+
+	if (key) {
+		for (i = 0; i < ARRAY_SIZE(key->mpi); i++)
+			mpi_free(key->mpi[i]);
+		kfree(key);
+	}
+}
+EXPORT_SYMBOL_GPL(public_key_destroy);
+
+/*
+ * Verify a signature using a public key.
+ */
+int public_key_verify_signature(const struct public_key *pk,
+				const struct public_key_signature *sig)
+{
+	const struct public_key_algorithm *algo;
+
+	BUG_ON(!pk);
+	BUG_ON(!pk->mpi[0]);
+	BUG_ON(!pk->mpi[1]);
+	BUG_ON(!sig);
+	BUG_ON(!sig->digest);
+	BUG_ON(!sig->mpi[0]);
+
+	algo = pk->algo;
+	if (!algo) {
+		if (pk->pkey_algo >= PKEY_ALGO__LAST)
+			return -ENOPKG;
+		algo = pkey_algo[pk->pkey_algo];
+		if (!algo)
+			return -ENOPKG;
+	}
+
+	if (!algo->verify_signature)
+		return -ENOTSUPP;
+
+	if (sig->nr_mpi != algo->n_sig_mpi) {
+		pr_debug("Signature has %u MPI not %u\n",
+			 sig->nr_mpi, algo->n_sig_mpi);
+		return -EINVAL;
+	}
+
+	return algo->verify_signature(pk, sig);
+}
+EXPORT_SYMBOL_GPL(public_key_verify_signature);
+
+static int public_key_verify_signature_2(const struct key *key,
+					 const struct public_key_signature *sig)
+{
+	const struct public_key *pk = key->payload.data;
+	return public_key_verify_signature(pk, sig);
+}
+
+/*
+ * Public key algorithm asymmetric key subtype
+ */
+struct asymmetric_key_subtype public_key_subtype = {
+	.owner			= THIS_MODULE,
+	.name			= "public_key",
+	.name_len		= sizeof("public_key") - 1,
+	.describe		= public_key_describe,
+	.destroy		= public_key_destroy,
+	.verify_signature	= public_key_verify_signature_2,
+};
+EXPORT_SYMBOL_GPL(public_key_subtype);

crypto/asymmetric_keys/public_key.h

@@ -0,0 +1,36 @@
+/* Public key algorithm internals
+ *
+ * See Documentation/crypto/asymmetric-keys.txt
+ *
+ * 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.
+ */
+
+#include <crypto/public_key.h>
+
+extern struct asymmetric_key_subtype public_key_subtype;
+
+/*
+ * Public key algorithm definition.
+ */
+struct public_key_algorithm {
+	const char	*name;
+	u8		n_pub_mpi;	/* Number of MPIs in public key */
+	u8		n_sec_mpi;	/* Number of MPIs in secret key */
+	u8		n_sig_mpi;	/* Number of MPIs in a signature */
+	int (*verify_signature)(const struct public_key *key,
+				const struct public_key_signature *sig);
+};
+
+extern const struct public_key_algorithm RSA_public_key_algorithm;
+
+/*
+ * public_key.c
+ */
+extern int public_key_verify_signature(const struct public_key *pk,
+				       const struct public_key_signature *sig);

crypto/asymmetric_keys/rsa.c

@@ -0,0 +1,278 @@
+/* RSA asymmetric public-key algorithm [RFC3447]
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "RSA: "fmt
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <crypto/algapi.h>
+#include "public_key.h"
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("RSA Public Key Algorithm");
+
+#define kenter(FMT, ...) \
+	pr_devel("==> %s("FMT")\n", __func__, ##__VA_ARGS__)
+#define kleave(FMT, ...) \
+	pr_devel("<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
+
+/*
+ * Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2].
+ */
+static const u8 RSA_digest_info_MD5[] = {
+	0x30, 0x20, 0x30, 0x0C, 0x06, 0x08,
+	0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05, /* OID */
+	0x05, 0x00, 0x04, 0x10
+};
+
+static const u8 RSA_digest_info_SHA1[] = {
+	0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
+	0x2B, 0x0E, 0x03, 0x02, 0x1A,
+	0x05, 0x00, 0x04, 0x14
+};
+
+static const u8 RSA_digest_info_RIPE_MD_160[] = {
+	0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
+	0x2B, 0x24, 0x03, 0x02, 0x01,
+	0x05, 0x00, 0x04, 0x14
+};
+
+static const u8 RSA_digest_info_SHA224[] = {
+	0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
+	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
+	0x05, 0x00, 0x04, 0x1C
+};
+
+static const u8 RSA_digest_info_SHA256[] = {
+	0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
+	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
+	0x05, 0x00, 0x04, 0x20
+};
+
+static const u8 RSA_digest_info_SHA384[] = {
+	0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
+	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
+	0x05, 0x00, 0x04, 0x30
+};
+
+static const u8 RSA_digest_info_SHA512[] = {
+	0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
+	0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
+	0x05, 0x00, 0x04, 0x40
+};
+
+static const struct {
+	const u8 *data;
+	size_t size;
+} RSA_ASN1_templates[PKEY_HASH__LAST] = {
+#define _(X) { RSA_digest_info_##X, sizeof(RSA_digest_info_##X) }
+	[HASH_ALGO_MD5]		= _(MD5),
+	[HASH_ALGO_SHA1]	= _(SHA1),
+	[HASH_ALGO_RIPE_MD_160]	= _(RIPE_MD_160),
+	[HASH_ALGO_SHA256]	= _(SHA256),
+	[HASH_ALGO_SHA384]	= _(SHA384),
+	[HASH_ALGO_SHA512]	= _(SHA512),
+	[HASH_ALGO_SHA224]	= _(SHA224),
+#undef _
+};
+
+/*
+ * RSAVP1() function [RFC3447 sec 5.2.2]
+ */
+static int RSAVP1(const struct public_key *key, MPI s, MPI *_m)
+{
+	MPI m;
+	int ret;
+
+	/* (1) Validate 0 <= s < n */
+	if (mpi_cmp_ui(s, 0) < 0) {
+		kleave(" = -EBADMSG [s < 0]");
+		return -EBADMSG;
+	}
+	if (mpi_cmp(s, key->rsa.n) >= 0) {
+		kleave(" = -EBADMSG [s >= n]");
+		return -EBADMSG;
+	}
+
+	m = mpi_alloc(0);
+	if (!m)
+		return -ENOMEM;
+
+	/* (2) m = s^e mod n */
+	ret = mpi_powm(m, s, key->rsa.e, key->rsa.n);
+	if (ret < 0) {
+		mpi_free(m);
+		return ret;
+	}
+
+	*_m = m;
+	return 0;
+}
+
+/*
+ * Integer to Octet String conversion [RFC3447 sec 4.1]
+ */
+static int RSA_I2OSP(MPI x, size_t xLen, u8 **_X)
+{
+	unsigned X_size, x_size;
+	int X_sign;
+	u8 *X;
+
+	/* Make sure the string is the right length.  The number should begin
+	 * with { 0x00, 0x01, ... } so we have to account for 15 leading zero
+	 * bits not being reported by MPI.
+	 */
+	x_size = mpi_get_nbits(x);
+	pr_devel("size(x)=%u xLen*8=%zu\n", x_size, xLen * 8);
+	if (x_size != xLen * 8 - 15)
+		return -ERANGE;
+
+	X = mpi_get_buffer(x, &X_size, &X_sign);
+	if (!X)
+		return -ENOMEM;
+	if (X_sign < 0) {
+		kfree(X);
+		return -EBADMSG;
+	}
+	if (X_size != xLen - 1) {
+		kfree(X);
+		return -EBADMSG;
+	}
+
+	*_X = X;
+	return 0;
+}
+
+/*
+ * Perform the RSA signature verification.
+ * @H: Value of hash of data and metadata
+ * @EM: The computed signature value
+ * @k: The size of EM (EM[0] is an invalid location but should hold 0x00)
+ * @hash_size: The size of H
+ * @asn1_template: The DigestInfo ASN.1 template
+ * @asn1_size: Size of asm1_template[]
+ */
+static int RSA_verify(const u8 *H, const u8 *EM, size_t k, size_t hash_size,
+		      const u8 *asn1_template, size_t asn1_size)
+{
+	unsigned PS_end, T_offset, i;
+
+	kenter(",,%zu,%zu,%zu", k, hash_size, asn1_size);
+
+	if (k < 2 + 1 + asn1_size + hash_size)
+		return -EBADMSG;
+
+	/* Decode the EMSA-PKCS1-v1_5 */
+	if (EM[1] != 0x01) {
+		kleave(" = -EBADMSG [EM[1] == %02u]", EM[1]);
+		return -EBADMSG;
+	}
+
+	T_offset = k - (asn1_size + hash_size);
+	PS_end = T_offset - 1;
+	if (EM[PS_end] != 0x00) {
+		kleave(" = -EBADMSG [EM[T-1] == %02u]", EM[PS_end]);
+		return -EBADMSG;
+	}
+
+	for (i = 2; i < PS_end; i++) {
+		if (EM[i] != 0xff) {
+			kleave(" = -EBADMSG [EM[PS%x] == %02u]", i - 2, EM[i]);
+			return -EBADMSG;
+		}
+	}
+
+	if (crypto_memneq(asn1_template, EM + T_offset, asn1_size) != 0) {
+		kleave(" = -EBADMSG [EM[T] ASN.1 mismatch]");
+		return -EBADMSG;
+	}
+
+	if (crypto_memneq(H, EM + T_offset + asn1_size, hash_size) != 0) {
+		kleave(" = -EKEYREJECTED [EM[T] hash mismatch]");
+		return -EKEYREJECTED;
+	}
+
+	kleave(" = 0");
+	return 0;
+}
+
+/*
+ * Perform the verification step [RFC3447 sec 8.2.2].
+ */
+static int RSA_verify_signature(const struct public_key *key,
+				const struct public_key_signature *sig)
+{
+	size_t tsize;
+	int ret;
+
+	/* Variables as per RFC3447 sec 8.2.2 */
+	const u8 *H = sig->digest;
+	u8 *EM = NULL;
+	MPI m = NULL;
+	size_t k;
+
+	kenter("");
+
+	if (!RSA_ASN1_templates[sig->pkey_hash_algo].data)
+		return -ENOTSUPP;
+
+	/* (1) Check the signature size against the public key modulus size */
+	k = mpi_get_nbits(key->rsa.n);
+	tsize = mpi_get_nbits(sig->rsa.s);
+
+	/* According to RFC 4880 sec 3.2, length of MPI is computed starting
+	 * from most significant bit.  So the RFC 3447 sec 8.2.2 size check
+	 * must be relaxed to conform with shorter signatures - so we fail here
+	 * only if signature length is longer than modulus size.
+	 */
+	pr_devel("step 1: k=%zu size(S)=%zu\n", k, tsize);
+	if (k < tsize) {
+		ret = -EBADMSG;
+		goto error;
+	}
+
+	/* Round up and convert to octets */
+	k = (k + 7) / 8;
+
+	/* (2b) Apply the RSAVP1 verification primitive to the public key */
+	ret = RSAVP1(key, sig->rsa.s, &m);
+	if (ret < 0)
+		goto error;
+
+	/* (2c) Convert the message representative (m) to an encoded message
+	 *      (EM) of length k octets.
+	 *
+	 *      NOTE!  The leading zero byte is suppressed by MPI, so we pass a
+	 *      pointer to the _preceding_ byte to RSA_verify()!
+	 */
+	ret = RSA_I2OSP(m, k, &EM);
+	if (ret < 0)
+		goto error;
+
+	ret = RSA_verify(H, EM - 1, k, sig->digest_size,
+			 RSA_ASN1_templates[sig->pkey_hash_algo].data,
+			 RSA_ASN1_templates[sig->pkey_hash_algo].size);
+
+error:
+	kfree(EM);
+	mpi_free(m);
+	kleave(" = %d", ret);
+	return ret;
+}
+
+const struct public_key_algorithm RSA_public_key_algorithm = {
+	.name		= "RSA",
+	.n_pub_mpi	= 2,
+	.n_sec_mpi	= 3,
+	.n_sig_mpi	= 1,
+	.verify_signature = RSA_verify_signature,
+};
+EXPORT_SYMBOL_GPL(RSA_public_key_algorithm);

crypto/asymmetric_keys/signature.c

@@ -0,0 +1,50 @@
+/* Signature verification with an asymmetric key
+ *
+ * See Documentation/security/asymmetric-keys.txt
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "SIG: "fmt
+#include <keys/asymmetric-subtype.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <crypto/public_key.h>
+#include "asymmetric_keys.h"
+
+/**
+ * verify_signature - Initiate the use of an asymmetric key to verify a signature
+ * @key: The asymmetric key to verify against
+ * @sig: The signature to check
+ *
+ * Returns 0 if successful or else an error.
+ */
+int verify_signature(const struct key *key,
+		     const struct public_key_signature *sig)
+{
+	const struct asymmetric_key_subtype *subtype;
+	int ret;
+
+	pr_devel("==>%s()\n", __func__);
+
+	if (key->type != &key_type_asymmetric)
+		return -EINVAL;
+	subtype = asymmetric_key_subtype(key);
+	if (!subtype ||
+	    !key->payload.data)
+		return -EINVAL;
+	if (!subtype->verify_signature)
+		return -ENOTSUPP;
+
+	ret = subtype->verify_signature(key, sig);
+
+	pr_devel("<==%s() = %d\n", __func__, ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(verify_signature);

crypto/asymmetric_keys/verify_pefile.c

@@ -0,0 +1,474 @@
+/* Parse a signed PE binary
+ *
+ * Copyright (C) 2014 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.
+ */
+
+#define pr_fmt(fmt) "PEFILE: "fmt
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/pe.h>
+#include <linux/asn1.h>
+#include <crypto/pkcs7.h>
+#include <crypto/hash.h>
+#include "verify_pefile.h"
+
+/*
+ * Parse a PE binary.
+ */
+static int pefile_parse_binary(const void *pebuf, unsigned int pelen,
+			       struct pefile_context *ctx)
+{
+	const struct mz_hdr *mz = pebuf;
+	const struct pe_hdr *pe;
+	const struct pe32_opt_hdr *pe32;
+	const struct pe32plus_opt_hdr *pe64;
+	const struct data_directory *ddir;
+	const struct data_dirent *dde;
+	const struct section_header *secs, *sec;
+	size_t cursor, datalen = pelen;
+
+	kenter("");
+
+#define chkaddr(base, x, s)						\
+	do {								\
+		if ((x) < base || (s) >= datalen || (x) > datalen - (s)) \
+			return -ELIBBAD;				\
+	} while (0)
+
+	chkaddr(0, 0, sizeof(*mz));
+	if (mz->magic != MZ_MAGIC)
+		return -ELIBBAD;
+	cursor = sizeof(*mz);
+
+	chkaddr(cursor, mz->peaddr, sizeof(*pe));
+	pe = pebuf + mz->peaddr;
+	if (pe->magic != PE_MAGIC)
+		return -ELIBBAD;
+	cursor = mz->peaddr + sizeof(*pe);
+
+	chkaddr(0, cursor, sizeof(pe32->magic));
+	pe32 = pebuf + cursor;
+	pe64 = pebuf + cursor;
+
+	switch (pe32->magic) {
+	case PE_OPT_MAGIC_PE32:
+		chkaddr(0, cursor, sizeof(*pe32));
+		ctx->image_checksum_offset =
+			(unsigned long)&pe32->csum - (unsigned long)pebuf;
+		ctx->header_size = pe32->header_size;
+		cursor += sizeof(*pe32);
+		ctx->n_data_dirents = pe32->data_dirs;
+		break;
+
+	case PE_OPT_MAGIC_PE32PLUS:
+		chkaddr(0, cursor, sizeof(*pe64));
+		ctx->image_checksum_offset =
+			(unsigned long)&pe64->csum - (unsigned long)pebuf;
+		ctx->header_size = pe64->header_size;
+		cursor += sizeof(*pe64);
+		ctx->n_data_dirents = pe64->data_dirs;
+		break;
+
+	default:
+		pr_debug("Unknown PEOPT magic = %04hx\n", pe32->magic);
+		return -ELIBBAD;
+	}
+
+	pr_debug("checksum @ %x\n", ctx->image_checksum_offset);
+	pr_debug("header size = %x\n", ctx->header_size);
+
+	if (cursor >= ctx->header_size || ctx->header_size >= datalen)
+		return -ELIBBAD;
+
+	if (ctx->n_data_dirents > (ctx->header_size - cursor) / sizeof(*dde))
+		return -ELIBBAD;
+
+	ddir = pebuf + cursor;
+	cursor += sizeof(*dde) * ctx->n_data_dirents;
+
+	ctx->cert_dirent_offset =
+		(unsigned long)&ddir->certs - (unsigned long)pebuf;
+	ctx->certs_size = ddir->certs.size;
+
+	if (!ddir->certs.virtual_address || !ddir->certs.size) {
+		pr_debug("Unsigned PE binary\n");
+		return -EKEYREJECTED;
+	}
+
+	chkaddr(ctx->header_size, ddir->certs.virtual_address,
+		ddir->certs.size);
+	ctx->sig_offset = ddir->certs.virtual_address;
+	ctx->sig_len = ddir->certs.size;
+	pr_debug("cert = %x @%x [%*ph]\n",
+		 ctx->sig_len, ctx->sig_offset,
+		 ctx->sig_len, pebuf + ctx->sig_offset);
+
+	ctx->n_sections = pe->sections;
+	if (ctx->n_sections > (ctx->header_size - cursor) / sizeof(*sec))
+		return -ELIBBAD;
+	ctx->secs = secs = pebuf + cursor;
+
+	return 0;
+}
+
+/*
+ * Check and strip the PE wrapper from around the signature and check that the
+ * remnant looks something like PKCS#7.
+ */
+static int pefile_strip_sig_wrapper(const void *pebuf,
+				    struct pefile_context *ctx)
+{
+	struct win_certificate wrapper;
+	const u8 *pkcs7;
+	unsigned len;
+
+	if (ctx->sig_len < sizeof(wrapper)) {
+		pr_debug("Signature wrapper too short\n");
+		return -ELIBBAD;
+	}
+
+	memcpy(&wrapper, pebuf + ctx->sig_offset, sizeof(wrapper));
+	pr_debug("sig wrapper = { %x, %x, %x }\n",
+		 wrapper.length, wrapper.revision, wrapper.cert_type);
+
+	/* Both pesign and sbsign round up the length of certificate table
+	 * (in optional header data directories) to 8 byte alignment.
+	 */
+	if (round_up(wrapper.length, 8) != ctx->sig_len) {
+		pr_debug("Signature wrapper len wrong\n");
+		return -ELIBBAD;
+	}
+	if (wrapper.revision != WIN_CERT_REVISION_2_0) {
+		pr_debug("Signature is not revision 2.0\n");
+		return -ENOTSUPP;
+	}
+	if (wrapper.cert_type != WIN_CERT_TYPE_PKCS_SIGNED_DATA) {
+		pr_debug("Signature certificate type is not PKCS\n");
+		return -ENOTSUPP;
+	}
+
+	/* It looks like the pkcs signature length in wrapper->length and the
+	 * size obtained from the data dir entries, which lists the total size
+	 * of certificate table, are both aligned to an octaword boundary, so
+	 * we may have to deal with some padding.
+	 */
+	ctx->sig_len = wrapper.length;
+	ctx->sig_offset += sizeof(wrapper);
+	ctx->sig_len -= sizeof(wrapper);
+	if (ctx->sig_len < 4) {
+		pr_debug("Signature data missing\n");
+		return -EKEYREJECTED;
+	}
+
+	/* What's left should be a PKCS#7 cert */
+	pkcs7 = pebuf + ctx->sig_offset;
+	if (pkcs7[0] != (ASN1_CONS_BIT | ASN1_SEQ))
+		goto not_pkcs7;
+
+	switch (pkcs7[1]) {
+	case 0 ... 0x7f:
+		len = pkcs7[1] + 2;
+		goto check_len;
+	case ASN1_INDEFINITE_LENGTH:
+		return 0;
+	case 0x81:
+		len = pkcs7[2] + 3;
+		goto check_len;
+	case 0x82:
+		len = ((pkcs7[2] << 8) | pkcs7[3]) + 4;
+		goto check_len;
+	case 0x83 ... 0xff:
+		return -EMSGSIZE;
+	default:
+		goto not_pkcs7;
+	}
+
+check_len:
+	if (len <= ctx->sig_len) {
+		/* There may be padding */
+		ctx->sig_len = len;
+		return 0;
+	}
+not_pkcs7:
+	pr_debug("Signature data not PKCS#7\n");
+	return -ELIBBAD;
+}
+
+/*
+ * Compare two sections for canonicalisation.
+ */
+static int pefile_compare_shdrs(const void *a, const void *b)
+{
+	const struct section_header *shdra = a;
+	const struct section_header *shdrb = b;
+	int rc;
+
+	if (shdra->data_addr > shdrb->data_addr)
+		return 1;
+	if (shdrb->data_addr > shdra->data_addr)
+		return -1;
+
+	if (shdra->virtual_address > shdrb->virtual_address)
+		return 1;
+	if (shdrb->virtual_address > shdra->virtual_address)
+		return -1;
+
+	rc = strcmp(shdra->name, shdrb->name);
+	if (rc != 0)
+		return rc;
+
+	if (shdra->virtual_size > shdrb->virtual_size)
+		return 1;
+	if (shdrb->virtual_size > shdra->virtual_size)
+		return -1;
+
+	if (shdra->raw_data_size > shdrb->raw_data_size)
+		return 1;
+	if (shdrb->raw_data_size > shdra->raw_data_size)
+		return -1;
+
+	return 0;
+}
+
+/*
+ * Load the contents of the PE binary into the digest, leaving out the image
+ * checksum and the certificate data block.
+ */
+static int pefile_digest_pe_contents(const void *pebuf, unsigned int pelen,
+				     struct pefile_context *ctx,
+				     struct shash_desc *desc)
+{
+	unsigned *canon, tmp, loop, i, hashed_bytes;
+	int ret;
+
+	/* Digest the header and data directory, but leave out the image
+	 * checksum and the data dirent for the signature.
+	 */
+	ret = crypto_shash_update(desc, pebuf, ctx->image_checksum_offset);
+	if (ret < 0)
+		return ret;
+
+	tmp = ctx->image_checksum_offset + sizeof(uint32_t);
+	ret = crypto_shash_update(desc, pebuf + tmp,
+				  ctx->cert_dirent_offset - tmp);
+	if (ret < 0)
+		return ret;
+
+	tmp = ctx->cert_dirent_offset + sizeof(struct data_dirent);
+	ret = crypto_shash_update(desc, pebuf + tmp, ctx->header_size - tmp);
+	if (ret < 0)
+		return ret;
+
+	canon = kcalloc(ctx->n_sections, sizeof(unsigned), GFP_KERNEL);
+	if (!canon)
+		return -ENOMEM;
+
+	/* We have to canonicalise the section table, so we perform an
+	 * insertion sort.
+	 */
+	canon[0] = 0;
+	for (loop = 1; loop < ctx->n_sections; loop++) {
+		for (i = 0; i < loop; i++) {
+			if (pefile_compare_shdrs(&ctx->secs[canon[i]],
+						 &ctx->secs[loop]) > 0) {
+				memmove(&canon[i + 1], &canon[i],
+					(loop - i) * sizeof(canon[0]));
+				break;
+			}
+		}
+		canon[i] = loop;
+	}
+
+	hashed_bytes = ctx->header_size;
+	for (loop = 0; loop < ctx->n_sections; loop++) {
+		i = canon[loop];
+		if (ctx->secs[i].raw_data_size == 0)
+			continue;
+		ret = crypto_shash_update(desc,
+					  pebuf + ctx->secs[i].data_addr,
+					  ctx->secs[i].raw_data_size);
+		if (ret < 0) {
+			kfree(canon);
+			return ret;
+		}
+		hashed_bytes += ctx->secs[i].raw_data_size;
+	}
+	kfree(canon);
+
+	if (pelen > hashed_bytes) {
+		tmp = hashed_bytes + ctx->certs_size;
+		ret = crypto_shash_update(desc,
+					  pebuf + hashed_bytes,
+					  pelen - tmp);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+
+/*
+ * Digest the contents of the PE binary, leaving out the image checksum and the
+ * certificate data block.
+ */
+static int pefile_digest_pe(const void *pebuf, unsigned int pelen,
+			    struct pefile_context *ctx)
+{
+	struct crypto_shash *tfm;
+	struct shash_desc *desc;
+	size_t digest_size, desc_size;
+	void *digest;
+	int ret;
+
+	kenter(",%u", ctx->digest_algo);
+
+	/* Allocate the hashing algorithm we're going to need and find out how
+	 * big the hash operational data will be.
+	 */
+	tfm = crypto_alloc_shash(hash_algo_name[ctx->digest_algo], 0, 0);
+	if (IS_ERR(tfm))
+		return (PTR_ERR(tfm) == -ENOENT) ? -ENOPKG : PTR_ERR(tfm);
+
+	desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
+	digest_size = crypto_shash_digestsize(tfm);
+
+	if (digest_size != ctx->digest_len) {
+		pr_debug("Digest size mismatch (%zx != %x)\n",
+			 digest_size, ctx->digest_len);
+		ret = -EBADMSG;
+		goto error_no_desc;
+	}
+	pr_debug("Digest: desc=%zu size=%zu\n", desc_size, digest_size);
+
+	ret = -ENOMEM;
+	desc = kzalloc(desc_size + digest_size, GFP_KERNEL);
+	if (!desc)
+		goto error_no_desc;
+
+	desc->tfm   = tfm;
+	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+	ret = crypto_shash_init(desc);
+	if (ret < 0)
+		goto error;
+
+	ret = pefile_digest_pe_contents(pebuf, pelen, ctx, desc);
+	if (ret < 0)
+		goto error;
+
+	digest = (void *)desc + desc_size;
+	ret = crypto_shash_final(desc, digest);
+	if (ret < 0)
+		goto error;
+
+	pr_debug("Digest calc = [%*ph]\n", ctx->digest_len, digest);
+
+	/* Check that the PE file digest matches that in the MSCODE part of the
+	 * PKCS#7 certificate.
+	 */
+	if (memcmp(digest, ctx->digest, ctx->digest_len) != 0) {
+		pr_debug("Digest mismatch\n");
+		ret = -EKEYREJECTED;
+	} else {
+		pr_debug("The digests match!\n");
+	}
+
+error:
+	kfree(desc);
+error_no_desc:
+	crypto_free_shash(tfm);
+	kleave(" = %d", ret);
+	return ret;
+}
+
+/**
+ * verify_pefile_signature - Verify the signature on a PE binary image
+ * @pebuf: Buffer containing the PE binary image
+ * @pelen: Length of the binary image
+ * @trust_keyring: Signing certificates to use as starting points
+ * @_trusted: Set to true if trustworth, false otherwise
+ *
+ * Validate that the certificate chain inside the PKCS#7 message inside the PE
+ * binary image intersects keys we already know and trust.
+ *
+ * Returns, in order of descending priority:
+ *
+ *  (*) -ELIBBAD if the image cannot be parsed, or:
+ *
+ *  (*) -EKEYREJECTED if a signature failed to match for which we have a valid
+ *	key, or:
+ *
+ *  (*) 0 if at least one signature chain intersects with the keys in the trust
+ *	keyring, or:
+ *
+ *  (*) -ENOPKG if a suitable crypto module couldn't be found for a check on a
+ *	chain.
+ *
+ *  (*) -ENOKEY if we couldn't find a match for any of the signature chains in
+ *	the message.
+ *
+ * May also return -ENOMEM.
+ */
+int verify_pefile_signature(const void *pebuf, unsigned pelen,
+			    struct key *trusted_keyring, bool *_trusted)
+{
+	struct pkcs7_message *pkcs7;
+	struct pefile_context ctx;
+	const void *data;
+	size_t datalen;
+	int ret;
+
+	kenter("");
+
+	memset(&ctx, 0, sizeof(ctx));
+	ret = pefile_parse_binary(pebuf, pelen, &ctx);
+	if (ret < 0)
+		return ret;
+
+	ret = pefile_strip_sig_wrapper(pebuf, &ctx);
+	if (ret < 0)
+		return ret;
+
+	pkcs7 = pkcs7_parse_message(pebuf + ctx.sig_offset, ctx.sig_len);
+	if (IS_ERR(pkcs7))
+		return PTR_ERR(pkcs7);
+	ctx.pkcs7 = pkcs7;
+
+	ret = pkcs7_get_content_data(ctx.pkcs7, &data, &datalen, false);
+	if (ret < 0 || datalen == 0) {
+		pr_devel("PKCS#7 message does not contain data\n");
+		ret = -EBADMSG;
+		goto error;
+	}
+
+	ret = mscode_parse(&ctx);
+	if (ret < 0)
+		goto error;
+
+	pr_debug("Digest: %u [%*ph]\n",
+		 ctx.digest_len, ctx.digest_len, ctx.digest);
+
+	/* Generate the digest and check against the PKCS7 certificate
+	 * contents.
+	 */
+	ret = pefile_digest_pe(pebuf, pelen, &ctx);
+	if (ret < 0)
+		goto error;
+
+	ret = pkcs7_verify(pkcs7);
+	if (ret < 0)
+		goto error;
+
+	ret = pkcs7_validate_trust(pkcs7, trusted_keyring, _trusted);
+
+error:
+	pkcs7_free_message(ctx.pkcs7);
+	return ret;
+}

crypto/asymmetric_keys/verify_pefile.h

@@ -0,0 +1,42 @@
+/* PE Binary parser bits
+ *
+ * Copyright (C) 2014 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.
+ */
+
+#include <linux/verify_pefile.h>
+#include <crypto/pkcs7.h>
+#include <crypto/hash_info.h>
+
+struct pefile_context {
+	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;
+	struct pkcs7_message *pkcs7;
+
+	/* PKCS#7 MS Individual Code Signing content */
+	const void	*digest;		/* Digest */
+	unsigned	digest_len;		/* Digest length */
+	enum hash_algo	digest_algo;		/* Digest algorithm */
+};
+
+#define kenter(FMT, ...)					\
+	pr_devel("==> %s("FMT")\n", __func__, ##__VA_ARGS__)
+#define kleave(FMT, ...) \
+	pr_devel("<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
+
+/*
+ * mscode_parser.c
+ */
+extern int mscode_parse(struct pefile_context *ctx);

crypto/asymmetric_keys/x509.asn1

@@ -0,0 +1,60 @@
+Certificate ::= SEQUENCE {
+	tbsCertificate		TBSCertificate ({ x509_note_tbs_certificate }),
+	signatureAlgorithm	AlgorithmIdentifier,
+	signature		BIT STRING ({ x509_note_signature })
+	}
+
+TBSCertificate ::= SEQUENCE {
+	version           [ 0 ]	Version DEFAULT,
+	serialNumber		CertificateSerialNumber ({ x509_note_serial }),
+	signature		AlgorithmIdentifier ({ x509_note_pkey_algo }),
+	issuer			Name ({ x509_note_issuer }),
+	validity		Validity,
+	subject			Name ({ x509_note_subject }),
+	subjectPublicKeyInfo	SubjectPublicKeyInfo,
+	issuerUniqueID    [ 1 ]	IMPLICIT UniqueIdentifier OPTIONAL,
+	subjectUniqueID   [ 2 ]	IMPLICIT UniqueIdentifier OPTIONAL,
+	extensions        [ 3 ]	Extensions OPTIONAL
+	}
+
+Version ::= INTEGER
+CertificateSerialNumber ::= INTEGER
+
+AlgorithmIdentifier ::= SEQUENCE {
+	algorithm		OBJECT IDENTIFIER ({ x509_note_OID }),
+	parameters		ANY OPTIONAL
+}
+
+Name ::= SEQUENCE OF RelativeDistinguishedName
+
+RelativeDistinguishedName ::= SET OF AttributeValueAssertion
+
+AttributeValueAssertion ::= SEQUENCE {
+	attributeType		OBJECT IDENTIFIER ({ x509_note_OID }),
+	attributeValue		ANY ({ x509_extract_name_segment })
+	}
+
+Validity ::= SEQUENCE {
+	notBefore		Time ({ x509_note_not_before }),
+	notAfter		Time ({ x509_note_not_after })
+	}
+
+Time ::= CHOICE {
+	utcTime			UTCTime,
+	generalTime		GeneralizedTime
+	}
+
+SubjectPublicKeyInfo ::= SEQUENCE {
+	algorithm		AlgorithmIdentifier,
+	subjectPublicKey	BIT STRING ({ x509_extract_key_data })
+	}
+
+UniqueIdentifier ::= BIT STRING
+
+Extensions ::= SEQUENCE OF Extension
+
+Extension ::= SEQUENCE {
+	extnid			OBJECT IDENTIFIER ({ x509_note_OID }),
+	critical		BOOLEAN DEFAULT,
+	extnValue		OCTET STRING ({ x509_process_extension })
+	}

crypto/asymmetric_keys/x509_cert_parser.c

@@ -0,0 +1,571 @@
+/* X.509 certificate 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.
+ */
+
+#define pr_fmt(fmt) "X.509: "fmt
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/oid_registry.h>
+#include "public_key.h"
+#include "x509_parser.h"
+#include "x509-asn1.h"
+#include "x509_rsakey-asn1.h"
+
+struct x509_parse_context {
+	struct x509_certificate	*cert;		/* Certificate being constructed */
+	unsigned long	data;			/* Start of data */
+	const void	*cert_start;		/* Start of cert content */
+	const void	*key;			/* Key data */
+	size_t		key_size;		/* Size of key data */
+	enum OID	last_oid;		/* Last OID encountered */
+	enum OID	algo_oid;		/* Algorithm OID */
+	unsigned char	nr_mpi;			/* Number of MPIs stored */
+	u8		o_size;			/* Size of organizationName (O) */
+	u8		cn_size;		/* Size of commonName (CN) */
+	u8		email_size;		/* Size of emailAddress */
+	u16		o_offset;		/* Offset of organizationName (O) */
+	u16		cn_offset;		/* Offset of commonName (CN) */
+	u16		email_offset;		/* Offset of emailAddress */
+};
+
+/*
+ * Free an X.509 certificate
+ */
+void x509_free_certificate(struct x509_certificate *cert)
+{
+	if (cert) {
+		public_key_destroy(cert->pub);
+		kfree(cert->issuer);
+		kfree(cert->subject);
+		kfree(cert->id);
+		kfree(cert->skid);
+		kfree(cert->authority);
+		kfree(cert->sig.digest);
+		mpi_free(cert->sig.rsa.s);
+		kfree(cert);
+	}
+}
+EXPORT_SYMBOL_GPL(x509_free_certificate);
+
+/*
+ * Parse an X.509 certificate
+ */
+struct x509_certificate *x509_cert_parse(const void *data, size_t datalen)
+{
+	struct x509_certificate *cert;
+	struct x509_parse_context *ctx;
+	struct asymmetric_key_id *kid;
+	long ret;
+
+	ret = -ENOMEM;
+	cert = kzalloc(sizeof(struct x509_certificate), GFP_KERNEL);
+	if (!cert)
+		goto error_no_cert;
+	cert->pub = kzalloc(sizeof(struct public_key), GFP_KERNEL);
+	if (!cert->pub)
+		goto error_no_ctx;
+	ctx = kzalloc(sizeof(struct x509_parse_context), GFP_KERNEL);
+	if (!ctx)
+		goto error_no_ctx;
+
+	ctx->cert = cert;
+	ctx->data = (unsigned long)data;
+
+	/* Attempt to decode the certificate */
+	ret = asn1_ber_decoder(&x509_decoder, ctx, data, datalen);
+	if (ret < 0)
+		goto error_decode;
+
+	/* Decode the public key */
+	ret = asn1_ber_decoder(&x509_rsakey_decoder, ctx,
+			       ctx->key, ctx->key_size);
+	if (ret < 0)
+		goto error_decode;
+
+	/* Generate cert issuer + serial number key ID */
+	kid = asymmetric_key_generate_id(cert->raw_serial,
+					 cert->raw_serial_size,
+					 cert->raw_issuer,
+					 cert->raw_issuer_size);
+	if (IS_ERR(kid)) {
+		ret = PTR_ERR(kid);
+		goto error_decode;
+	}
+	cert->id = kid;
+
+	kfree(ctx);
+	return cert;
+
+error_decode:
+	kfree(ctx);
+error_no_ctx:
+	x509_free_certificate(cert);
+error_no_cert:
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(x509_cert_parse);
+
+/*
+ * Note an OID when we find one for later processing when we know how
+ * to interpret it.
+ */
+int x509_note_OID(void *context, size_t hdrlen,
+	     unsigned char tag,
+	     const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+
+	ctx->last_oid = look_up_OID(value, vlen);
+	if (ctx->last_oid == OID__NR) {
+		char buffer[50];
+		sprint_oid(value, vlen, buffer, sizeof(buffer));
+		pr_debug("Unknown OID: [%lu] %s\n",
+			 (unsigned long)value - ctx->data, buffer);
+	}
+	return 0;
+}
+
+/*
+ * Save the position of the TBS data so that we can check the signature over it
+ * later.
+ */
+int x509_note_tbs_certificate(void *context, size_t hdrlen,
+			      unsigned char tag,
+			      const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+
+	pr_debug("x509_note_tbs_certificate(,%zu,%02x,%ld,%zu)!\n",
+		 hdrlen, tag, (unsigned long)value - ctx->data, vlen);
+
+	ctx->cert->tbs = value - hdrlen;
+	ctx->cert->tbs_size = vlen + hdrlen;
+	return 0;
+}
+
+/*
+ * Record the public key algorithm
+ */
+int x509_note_pkey_algo(void *context, size_t hdrlen,
+			unsigned char tag,
+			const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+
+	pr_debug("PubKey Algo: %u\n", ctx->last_oid);
+
+	switch (ctx->last_oid) {
+	case OID_md2WithRSAEncryption:
+	case OID_md3WithRSAEncryption:
+	default:
+		return -ENOPKG; /* Unsupported combination */
+
+	case OID_md4WithRSAEncryption:
+		ctx->cert->sig.pkey_hash_algo = HASH_ALGO_MD5;
+		ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA;
+		break;
+
+	case OID_sha1WithRSAEncryption:
+		ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA1;
+		ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA;
+		break;
+
+	case OID_sha256WithRSAEncryption:
+		ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA256;
+		ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA;
+		break;
+
+	case OID_sha384WithRSAEncryption:
+		ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA384;
+		ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA;
+		break;
+
+	case OID_sha512WithRSAEncryption:
+		ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA512;
+		ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA;
+		break;
+
+	case OID_sha224WithRSAEncryption:
+		ctx->cert->sig.pkey_hash_algo = HASH_ALGO_SHA224;
+		ctx->cert->sig.pkey_algo = PKEY_ALGO_RSA;
+		break;
+	}
+
+	ctx->algo_oid = ctx->last_oid;
+	return 0;
+}
+
+/*
+ * Note the whereabouts and type of the signature.
+ */
+int x509_note_signature(void *context, size_t hdrlen,
+			unsigned char tag,
+			const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+
+	pr_debug("Signature type: %u size %zu\n", ctx->last_oid, vlen);
+
+	if (ctx->last_oid != ctx->algo_oid) {
+		pr_warn("Got cert with pkey (%u) and sig (%u) algorithm OIDs\n",
+			ctx->algo_oid, ctx->last_oid);
+		return -EINVAL;
+	}
+
+	ctx->cert->raw_sig = value;
+	ctx->cert->raw_sig_size = vlen;
+	return 0;
+}
+
+/*
+ * Note the certificate serial number
+ */
+int x509_note_serial(void *context, size_t hdrlen,
+		     unsigned char tag,
+		     const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+	ctx->cert->raw_serial = value;
+	ctx->cert->raw_serial_size = vlen;
+	return 0;
+}
+
+/*
+ * Note some of the name segments from which we'll fabricate a name.
+ */
+int x509_extract_name_segment(void *context, size_t hdrlen,
+			      unsigned char tag,
+			      const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+
+	switch (ctx->last_oid) {
+	case OID_commonName:
+		ctx->cn_size = vlen;
+		ctx->cn_offset = (unsigned long)value - ctx->data;
+		break;
+	case OID_organizationName:
+		ctx->o_size = vlen;
+		ctx->o_offset = (unsigned long)value - ctx->data;
+		break;
+	case OID_email_address:
+		ctx->email_size = vlen;
+		ctx->email_offset = (unsigned long)value - ctx->data;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/*
+ * Fabricate and save the issuer and subject names
+ */
+static int x509_fabricate_name(struct x509_parse_context *ctx, size_t hdrlen,
+			       unsigned char tag,
+			       char **_name, size_t vlen)
+{
+	const void *name, *data = (const void *)ctx->data;
+	size_t namesize;
+	char *buffer;
+
+	if (*_name)
+		return -EINVAL;
+
+	/* Empty name string if no material */
+	if (!ctx->cn_size && !ctx->o_size && !ctx->email_size) {
+		buffer = kmalloc(1, GFP_KERNEL);
+		if (!buffer)
+			return -ENOMEM;
+		buffer[0] = 0;
+		goto done;
+	}
+
+	if (ctx->cn_size && ctx->o_size) {
+		/* Consider combining O and CN, but use only the CN if it is
+		 * prefixed by the O, or a significant portion thereof.
+		 */
+		namesize = ctx->cn_size;
+		name = data + ctx->cn_offset;
+		if (ctx->cn_size >= ctx->o_size &&
+		    memcmp(data + ctx->cn_offset, data + ctx->o_offset,
+			   ctx->o_size) == 0)
+			goto single_component;
+		if (ctx->cn_size >= 7 &&
+		    ctx->o_size >= 7 &&
+		    memcmp(data + ctx->cn_offset, data + ctx->o_offset, 7) == 0)
+			goto single_component;
+
+		buffer = kmalloc(ctx->o_size + 2 + ctx->cn_size + 1,
+				 GFP_KERNEL);
+		if (!buffer)
+			return -ENOMEM;
+
+		memcpy(buffer,
+		       data + ctx->o_offset, ctx->o_size);
+		buffer[ctx->o_size + 0] = ':';
+		buffer[ctx->o_size + 1] = ' ';
+		memcpy(buffer + ctx->o_size + 2,
+		       data + ctx->cn_offset, ctx->cn_size);
+		buffer[ctx->o_size + 2 + ctx->cn_size] = 0;
+		goto done;
+
+	} else if (ctx->cn_size) {
+		namesize = ctx->cn_size;
+		name = data + ctx->cn_offset;
+	} else if (ctx->o_size) {
+		namesize = ctx->o_size;
+		name = data + ctx->o_offset;
+	} else {
+		namesize = ctx->email_size;
+		name = data + ctx->email_offset;
+	}
+
+single_component:
+	buffer = kmalloc(namesize + 1, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+	memcpy(buffer, name, namesize);
+	buffer[namesize] = 0;
+
+done:
+	*_name = buffer;
+	ctx->cn_size = 0;
+	ctx->o_size = 0;
+	ctx->email_size = 0;
+	return 0;
+}
+
+int x509_note_issuer(void *context, size_t hdrlen,
+		     unsigned char tag,
+		     const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+	ctx->cert->raw_issuer = value;
+	ctx->cert->raw_issuer_size = vlen;
+	return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->issuer, vlen);
+}
+
+int x509_note_subject(void *context, size_t hdrlen,
+		      unsigned char tag,
+		      const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+	ctx->cert->raw_subject = value;
+	ctx->cert->raw_subject_size = vlen;
+	return x509_fabricate_name(ctx, hdrlen, tag, &ctx->cert->subject, vlen);
+}
+
+/*
+ * Extract the data for the public key algorithm
+ */
+int x509_extract_key_data(void *context, size_t hdrlen,
+			  unsigned char tag,
+			  const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+
+	if (ctx->last_oid != OID_rsaEncryption)
+		return -ENOPKG;
+
+	ctx->cert->pub->pkey_algo = PKEY_ALGO_RSA;
+
+	/* Discard the BIT STRING metadata */
+	ctx->key = value + 1;
+	ctx->key_size = vlen - 1;
+	return 0;
+}
+
+/*
+ * Extract a RSA public key value
+ */
+int rsa_extract_mpi(void *context, size_t hdrlen,
+		    unsigned char tag,
+		    const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+	MPI mpi;
+
+	if (ctx->nr_mpi >= ARRAY_SIZE(ctx->cert->pub->mpi)) {
+		pr_err("Too many public key MPIs in certificate\n");
+		return -EBADMSG;
+	}
+
+	mpi = mpi_read_raw_data(value, vlen);
+	if (!mpi)
+		return -ENOMEM;
+
+	ctx->cert->pub->mpi[ctx->nr_mpi++] = mpi;
+	return 0;
+}
+
+/* The keyIdentifier in AuthorityKeyIdentifier SEQUENCE is tag(CONT,PRIM,0) */
+#define SEQ_TAG_KEYID (ASN1_CONT << 6)
+
+/*
+ * Process certificate extensions that are used to qualify the certificate.
+ */
+int x509_process_extension(void *context, size_t hdrlen,
+			   unsigned char tag,
+			   const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+	struct asymmetric_key_id *kid;
+	const unsigned char *v = value;
+	int i;
+
+	pr_debug("Extension: %u\n", ctx->last_oid);
+
+	if (ctx->last_oid == OID_subjectKeyIdentifier) {
+		/* Get hold of the key fingerprint */
+		if (ctx->cert->skid || vlen < 3)
+			return -EBADMSG;
+		if (v[0] != ASN1_OTS || v[1] != vlen - 2)
+			return -EBADMSG;
+		v += 2;
+		vlen -= 2;
+
+		ctx->cert->raw_skid_size = vlen;
+		ctx->cert->raw_skid = v;
+		kid = asymmetric_key_generate_id(ctx->cert->raw_subject,
+						 ctx->cert->raw_subject_size,
+						 v, vlen);
+		if (IS_ERR(kid))
+			return PTR_ERR(kid);
+		ctx->cert->skid = kid;
+		pr_debug("subjkeyid %*phN\n", kid->len, kid->data);
+		return 0;
+	}
+
+	if (ctx->last_oid == OID_authorityKeyIdentifier) {
+		/* Get hold of the CA key fingerprint */
+		if (ctx->cert->authority || vlen < 5)
+			return -EBADMSG;
+
+		/* Authority Key Identifier must be a Constructed SEQUENCE */
+		if (v[0] != (ASN1_SEQ | (ASN1_CONS << 5)))
+			return -EBADMSG;
+
+		/* Authority Key Identifier is not indefinite length */
+		if (unlikely(vlen == ASN1_INDEFINITE_LENGTH))
+			return -EBADMSG;
+
+		if (vlen < ASN1_INDEFINITE_LENGTH) {
+			/* Short Form length */
+			if (v[1] != vlen - 2 ||
+			    v[2] != SEQ_TAG_KEYID ||
+			    v[3] > vlen - 4)
+				return -EBADMSG;
+
+			vlen = v[3];
+			v += 4;
+		} else {
+			/* Long Form length */
+			size_t seq_len = 0;
+			size_t sub = v[1] - ASN1_INDEFINITE_LENGTH;
+
+			if (sub > 2)
+				return -EBADMSG;
+
+			/* calculate the length from subsequent octets */
+			v += 2;
+			for (i = 0; i < sub; i++) {
+				seq_len <<= 8;
+				seq_len |= v[i];
+			}
+
+			if (seq_len != vlen - 2 - sub ||
+			    v[sub] != SEQ_TAG_KEYID ||
+			    v[sub + 1] > vlen - 4 - sub)
+				return -EBADMSG;
+
+			vlen = v[sub + 1];
+			v += (sub + 2);
+		}
+
+		kid = asymmetric_key_generate_id(ctx->cert->raw_issuer,
+						 ctx->cert->raw_issuer_size,
+						 v, vlen);
+		if (IS_ERR(kid))
+			return PTR_ERR(kid);
+		pr_debug("authkeyid %*phN\n", kid->len, kid->data);
+		ctx->cert->authority = kid;
+		return 0;
+	}
+
+	return 0;
+}
+
+/*
+ * Record a certificate time.
+ */
+static int x509_note_time(struct tm *tm,  size_t hdrlen,
+			  unsigned char tag,
+			  const unsigned char *value, size_t vlen)
+{
+	const unsigned char *p = value;
+
+#define dec2bin(X) ((X) - '0')
+#define DD2bin(P) ({ unsigned x = dec2bin(P[0]) * 10 + dec2bin(P[1]); P += 2; x; })
+
+	if (tag == ASN1_UNITIM) {
+		/* UTCTime: YYMMDDHHMMSSZ */
+		if (vlen != 13)
+			goto unsupported_time;
+		tm->tm_year = DD2bin(p);
+		if (tm->tm_year >= 50)
+			tm->tm_year += 1900;
+		else
+			tm->tm_year += 2000;
+	} else if (tag == ASN1_GENTIM) {
+		/* GenTime: YYYYMMDDHHMMSSZ */
+		if (vlen != 15)
+			goto unsupported_time;
+		tm->tm_year = DD2bin(p) * 100 + DD2bin(p);
+	} else {
+		goto unsupported_time;
+	}
+
+	tm->tm_year -= 1900;
+	tm->tm_mon  = DD2bin(p) - 1;
+	tm->tm_mday = DD2bin(p);
+	tm->tm_hour = DD2bin(p);
+	tm->tm_min  = DD2bin(p);
+	tm->tm_sec  = DD2bin(p);
+
+	if (*p != 'Z')
+		goto unsupported_time;
+
+	return 0;
+
+unsupported_time:
+	pr_debug("Got unsupported time [tag %02x]: '%*.*s'\n",
+		 tag, (int)vlen, (int)vlen, value);
+	return -EBADMSG;
+}
+
+int x509_note_not_before(void *context, size_t hdrlen,
+			 unsigned char tag,
+			 const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+	return x509_note_time(&ctx->cert->valid_from, hdrlen, tag, value, vlen);
+}
+
+int x509_note_not_after(void *context, size_t hdrlen,
+			unsigned char tag,
+			const void *value, size_t vlen)
+{
+	struct x509_parse_context *ctx = context;
+	return x509_note_time(&ctx->cert->valid_to, hdrlen, tag, value, vlen);
+}

crypto/asymmetric_keys/x509_parser.h

@@ -0,0 +1,57 @@
+/* X.509 certificate parser internal definitions
+ *
+ * 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.
+ */
+
+#include <linux/time.h>
+#include <crypto/public_key.h>
+
+struct x509_certificate {
+	struct x509_certificate *next;
+	struct x509_certificate *signer;	/* Certificate that signed this one */
+	struct public_key *pub;			/* Public key details */
+	struct public_key_signature sig;	/* Signature parameters */
+	char		*issuer;		/* Name of certificate issuer */
+	char		*subject;		/* Name of certificate subject */
+	struct asymmetric_key_id *id;		/* Serial number + issuer */
+	struct asymmetric_key_id *skid;		/* Subject + subjectKeyId (optional) */
+	struct asymmetric_key_id *authority;	/* Authority key identifier (optional) */
+	struct tm	valid_from;
+	struct tm	valid_to;
+	const void	*tbs;			/* Signed data */
+	unsigned	tbs_size;		/* Size of signed data */
+	unsigned	raw_sig_size;		/* Size of sigature */
+	const void	*raw_sig;		/* Signature data */
+	const void	*raw_serial;		/* Raw serial number in ASN.1 */
+	unsigned	raw_serial_size;
+	unsigned	raw_issuer_size;
+	const void	*raw_issuer;		/* Raw issuer name in ASN.1 */
+	const void	*raw_subject;		/* Raw subject name in ASN.1 */
+	unsigned	raw_subject_size;
+	unsigned	raw_skid_size;
+	const void	*raw_skid;		/* Raw subjectKeyId in ASN.1 */
+	unsigned	index;
+	bool		seen;			/* Infinite recursion prevention */
+	bool		verified;
+	bool		trusted;
+	bool		unsupported_crypto;	/* T if can't be verified due to missing crypto */
+};
+
+/*
+ * x509_cert_parser.c
+ */
+extern void x509_free_certificate(struct x509_certificate *cert);
+extern struct x509_certificate *x509_cert_parse(const void *data, size_t datalen);
+
+/*
+ * x509_public_key.c
+ */
+extern int x509_get_sig_params(struct x509_certificate *cert);
+extern int x509_check_signature(const struct public_key *pub,
+				struct x509_certificate *cert);

crypto/asymmetric_keys/x509_public_key.c

@@ -0,0 +1,364 @@
+/* Instantiate a public key crypto key from an X.509 Certificate
+ *
+ * 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.
+ */
+
+#define pr_fmt(fmt) "X.509: "fmt
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/mpi.h>
+#include <linux/asn1_decoder.h>
+#include <keys/asymmetric-subtype.h>
+#include <keys/asymmetric-parser.h>
+#include <keys/system_keyring.h>
+#include <crypto/hash.h>
+#include "asymmetric_keys.h"
+#include "public_key.h"
+#include "x509_parser.h"
+
+static bool use_builtin_keys;
+static struct asymmetric_key_id *ca_keyid;
+
+#ifndef MODULE
+static int __init ca_keys_setup(char *str)
+{
+	if (!str)		/* default system keyring */
+		return 1;
+
+	if (strncmp(str, "id:", 3) == 0) {
+		struct asymmetric_key_id *p;
+		p = asymmetric_key_hex_to_key_id(str + 3);
+		if (p == ERR_PTR(-EINVAL))
+			pr_err("Unparsable hex string in ca_keys\n");
+		else if (!IS_ERR(p))
+			ca_keyid = p;	/* owner key 'id:xxxxxx' */
+	} else if (strcmp(str, "builtin") == 0) {
+		use_builtin_keys = true;
+	}
+
+	return 1;
+}
+__setup("ca_keys=", ca_keys_setup);
+#endif
+
+/**
+ * x509_request_asymmetric_key - Request a key by X.509 certificate params.
+ * @keyring: The keys to search.
+ * @kid: The key ID.
+ * @partial: Use partial match if true, exact if false.
+ *
+ * Find a key in the given keyring by subject name and key ID.  These might,
+ * for instance, be the issuer name and the authority key ID of an X.509
+ * certificate that needs to be verified.
+ */
+struct key *x509_request_asymmetric_key(struct key *keyring,
+					const struct asymmetric_key_id *kid,
+					bool partial)
+{
+	key_ref_t key;
+	char *id, *p;
+
+	/* Construct an identifier "id:<keyid>". */
+	p = id = kmalloc(2 + 1 + kid->len * 2 + 1, GFP_KERNEL);
+	if (!id)
+		return ERR_PTR(-ENOMEM);
+
+	if (partial) {
+		*p++ = 'i';
+		*p++ = 'd';
+	} else {
+		*p++ = 'e';
+		*p++ = 'x';
+	}
+	*p++ = ':';
+	p = bin2hex(p, kid->data, kid->len);
+	*p = 0;
+
+	pr_debug("Look up: \"%s\"\n", id);
+
+	key = keyring_search(make_key_ref(keyring, 1),
+			     &key_type_asymmetric, id);
+	if (IS_ERR(key))
+		pr_debug("Request for key '%s' err %ld\n", id, PTR_ERR(key));
+	kfree(id);
+
+	if (IS_ERR(key)) {
+		switch (PTR_ERR(key)) {
+			/* Hide some search errors */
+		case -EACCES:
+		case -ENOTDIR:
+		case -EAGAIN:
+			return ERR_PTR(-ENOKEY);
+		default:
+			return ERR_CAST(key);
+		}
+	}
+
+	pr_devel("<==%s() = 0 [%x]\n", __func__,
+		 key_serial(key_ref_to_ptr(key)));
+	return key_ref_to_ptr(key);
+}
+EXPORT_SYMBOL_GPL(x509_request_asymmetric_key);
+
+/*
+ * Set up the signature parameters in an X.509 certificate.  This involves
+ * digesting the signed data and extracting the signature.
+ */
+int x509_get_sig_params(struct x509_certificate *cert)
+{
+	struct crypto_shash *tfm;
+	struct shash_desc *desc;
+	size_t digest_size, desc_size;
+	void *digest;
+	int ret;
+
+	pr_devel("==>%s()\n", __func__);
+
+	if (cert->unsupported_crypto)
+		return -ENOPKG;
+	if (cert->sig.rsa.s)
+		return 0;
+
+	cert->sig.rsa.s = mpi_read_raw_data(cert->raw_sig, cert->raw_sig_size);
+	if (!cert->sig.rsa.s)
+		return -ENOMEM;
+	cert->sig.nr_mpi = 1;
+
+	/* Allocate the hashing algorithm we're going to need and find out how
+	 * big the hash operational data will be.
+	 */
+	tfm = crypto_alloc_shash(hash_algo_name[cert->sig.pkey_hash_algo], 0, 0);
+	if (IS_ERR(tfm)) {
+		if (PTR_ERR(tfm) == -ENOENT) {
+			cert->unsupported_crypto = true;
+			return -ENOPKG;
+		}
+		return PTR_ERR(tfm);
+	}
+
+	desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
+	digest_size = crypto_shash_digestsize(tfm);
+
+	/* We allocate the hash operational data storage on the end of the
+	 * digest storage space.
+	 */
+	ret = -ENOMEM;
+	digest = kzalloc(digest_size + desc_size, GFP_KERNEL);
+	if (!digest)
+		goto error;
+
+	cert->sig.digest = digest;
+	cert->sig.digest_size = digest_size;
+
+	desc = digest + digest_size;
+	desc->tfm = tfm;
+	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	ret = crypto_shash_init(desc);
+	if (ret < 0)
+		goto error;
+	might_sleep();
+	ret = crypto_shash_finup(desc, cert->tbs, cert->tbs_size, digest);
+error:
+	crypto_free_shash(tfm);
+	pr_devel("<==%s() = %d\n", __func__, ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(x509_get_sig_params);
+
+/*
+ * Check the signature on a certificate using the provided public key
+ */
+int x509_check_signature(const struct public_key *pub,
+			 struct x509_certificate *cert)
+{
+	int ret;
+
+	pr_devel("==>%s()\n", __func__);
+
+	ret = x509_get_sig_params(cert);
+	if (ret < 0)
+		return ret;
+
+	ret = public_key_verify_signature(pub, &cert->sig);
+	if (ret == -ENOPKG)
+		cert->unsupported_crypto = true;
+	pr_debug("Cert Verification: %d\n", ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(x509_check_signature);
+
+/*
+ * Check the new certificate against the ones in the trust keyring.  If one of
+ * those is the signing key and validates the new certificate, then mark the
+ * new certificate as being trusted.
+ *
+ * Return 0 if the new certificate was successfully validated, 1 if we couldn't
+ * find a matching parent certificate in the trusted list and an error if there
+ * is a matching certificate but the signature check fails.
+ */
+static int x509_validate_trust(struct x509_certificate *cert,
+			       struct key *trust_keyring)
+{
+	struct key *key;
+	int ret = 1;
+
+	if (!trust_keyring)
+		return -EOPNOTSUPP;
+
+	if (ca_keyid && !asymmetric_key_id_partial(cert->authority, ca_keyid))
+		return -EPERM;
+
+	key = x509_request_asymmetric_key(trust_keyring, cert->authority,
+					  false);
+	if (!IS_ERR(key))  {
+		if (!use_builtin_keys
+		    || test_bit(KEY_FLAG_BUILTIN, &key->flags))
+			ret = x509_check_signature(key->payload.data, cert);
+		key_put(key);
+	}
+	return ret;
+}
+
+/*
+ * Attempt to parse a data blob for a key as an X509 certificate.
+ */
+static int x509_key_preparse(struct key_preparsed_payload *prep)
+{
+	struct asymmetric_key_ids *kids;
+	struct x509_certificate *cert;
+	const char *q;
+	size_t srlen, sulen;
+	char *desc = NULL, *p;
+	int ret;
+
+	cert = x509_cert_parse(prep->data, prep->datalen);
+	if (IS_ERR(cert))
+		return PTR_ERR(cert);
+
+	pr_devel("Cert Issuer: %s\n", cert->issuer);
+	pr_devel("Cert Subject: %s\n", cert->subject);
+
+	if (cert->pub->pkey_algo >= PKEY_ALGO__LAST ||
+	    cert->sig.pkey_algo >= PKEY_ALGO__LAST ||
+	    cert->sig.pkey_hash_algo >= PKEY_HASH__LAST ||
+	    !pkey_algo[cert->pub->pkey_algo] ||
+	    !pkey_algo[cert->sig.pkey_algo] ||
+	    !hash_algo_name[cert->sig.pkey_hash_algo]) {
+		ret = -ENOPKG;
+		goto error_free_cert;
+	}
+
+	pr_devel("Cert Key Algo: %s\n", pkey_algo_name[cert->pub->pkey_algo]);
+	pr_devel("Cert Valid From: %04ld-%02d-%02d %02d:%02d:%02d\n",
+		 cert->valid_from.tm_year + 1900, cert->valid_from.tm_mon + 1,
+		 cert->valid_from.tm_mday, cert->valid_from.tm_hour,
+		 cert->valid_from.tm_min,  cert->valid_from.tm_sec);
+	pr_devel("Cert Valid To: %04ld-%02d-%02d %02d:%02d:%02d\n",
+		 cert->valid_to.tm_year + 1900, cert->valid_to.tm_mon + 1,
+		 cert->valid_to.tm_mday, cert->valid_to.tm_hour,
+		 cert->valid_to.tm_min,  cert->valid_to.tm_sec);
+	pr_devel("Cert Signature: %s + %s\n",
+		 pkey_algo_name[cert->sig.pkey_algo],
+		 hash_algo_name[cert->sig.pkey_hash_algo]);
+
+	cert->pub->algo = pkey_algo[cert->pub->pkey_algo];
+	cert->pub->id_type = PKEY_ID_X509;
+
+	/* Check the signature on the key if it appears to be self-signed */
+	if (!cert->authority ||
+	    asymmetric_key_id_same(cert->skid, cert->authority)) {
+		ret = x509_check_signature(cert->pub, cert); /* self-signed */
+		if (ret < 0)
+			goto error_free_cert;
+	} else if (!prep->trusted) {
+		ret = x509_validate_trust(cert, get_system_trusted_keyring());
+		if (!ret)
+			prep->trusted = 1;
+	}
+
+	/* Propose a description */
+	sulen = strlen(cert->subject);
+	if (cert->raw_skid) {
+		srlen = cert->raw_skid_size;
+		q = cert->raw_skid;
+	} else {
+		srlen = cert->raw_serial_size;
+		q = cert->raw_serial;
+	}
+	if (srlen > 1 && *q == 0) {
+		srlen--;
+		q++;
+	}
+
+	ret = -ENOMEM;
+	desc = kmalloc(sulen + 2 + srlen * 2 + 1, GFP_KERNEL);
+	if (!desc)
+		goto error_free_cert;
+	p = memcpy(desc, cert->subject, sulen);
+	p += sulen;
+	*p++ = ':';
+	*p++ = ' ';
+	p = bin2hex(p, q, srlen);
+	*p = 0;
+
+	kids = kmalloc(sizeof(struct asymmetric_key_ids), GFP_KERNEL);
+	if (!kids)
+		goto error_free_desc;
+	kids->id[0] = cert->id;
+	kids->id[1] = cert->skid;
+
+	/* We're pinning the module by being linked against it */
+	__module_get(public_key_subtype.owner);
+	prep->type_data[0] = &public_key_subtype;
+	prep->type_data[1] = kids;
+	prep->payload[0] = cert->pub;
+	prep->description = desc;
+	prep->quotalen = 100;
+
+	/* We've finished with the certificate */
+	cert->pub = NULL;
+	cert->id = NULL;
+	cert->skid = NULL;
+	desc = NULL;
+	ret = 0;
+
+error_free_desc:
+	kfree(desc);
+error_free_cert:
+	x509_free_certificate(cert);
+	return ret;
+}
+
+static struct asymmetric_key_parser x509_key_parser = {
+	.owner	= THIS_MODULE,
+	.name	= "x509",
+	.parse	= x509_key_preparse,
+};
+
+/*
+ * Module stuff
+ */
+static int __init x509_key_init(void)
+{
+	return register_asymmetric_key_parser(&x509_key_parser);
+}
+
+static void __exit x509_key_exit(void)
+{
+	unregister_asymmetric_key_parser(&x509_key_parser);
+}
+
+module_init(x509_key_init);
+module_exit(x509_key_exit);
+
+MODULE_DESCRIPTION("X.509 certificate parser");
+MODULE_LICENSE("GPL");

crypto/asymmetric_keys/x509_rsakey.asn1

@@ -0,0 +1,4 @@
+RSAPublicKey ::= SEQUENCE {
+	modulus			INTEGER ({ rsa_extract_mpi }),	-- n
+	publicExponent		INTEGER ({ rsa_extract_mpi })	-- e
+	}