Initial commit

crypto/asymmetric_keys/.gitignore

@@ -0,0 +1 @@
+*-asn1.[ch]

crypto/asymmetric_keys/Kconfig

@@ -0,0 +1,38 @@
+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
+	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"
+	depends on ASYMMETRIC_PUBLIC_KEY_SUBTYPE
+	select MPILIB_EXTRA
+	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 procides 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.
+
+endif # ASYMMETRIC_KEY_TYPE

crypto/asymmetric_keys/Makefile

@@ -0,0 +1,27 @@
+#
+# 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

crypto/asymmetric_keys/asymmetric_keys.h

@@ -0,0 +1,15 @@
+/* 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.
+ */
+
+static inline const char *asymmetric_key_id(const struct key *key)
+{
+	return key->type_data.p[1];
+}

crypto/asymmetric_keys/asymmetric_type.c

@@ -0,0 +1,274 @@
+/* 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 "asymmetric_keys.h"
+
+MODULE_LICENSE("GPL");
+
+static LIST_HEAD(asymmetric_key_parsers);
+static DECLARE_RWSEM(asymmetric_key_parsers_sem);
+
+/*
+ * Match asymmetric keys on (part of) their name
+ * We have some shorthand methods for matching keys.  We allow:
+ *
+ *	"<desc>"	- request a key by description
+ *	"id:<id>"	- request a key matching the ID
+ *	"<subtype>:<id>" - request a key of a subtype
+ */
+static int asymmetric_key_match(const struct key *key, const void *description)
+{
+	const struct asymmetric_key_subtype *subtype = asymmetric_key_subtype(key);
+	const char *spec = description;
+	const char *id, *kid;
+	ptrdiff_t speclen;
+	size_t idlen, kidlen;
+
+	if (!subtype || !spec || !*spec)
+		return 0;
+
+	/* See if the full key description matches as is */
+	if (key->description && strcmp(key->description, description) == 0)
+		return 1;
+
+	/* All tests from here on break the criterion description into a
+	 * specifier, a colon and then an identifier.
+	 */
+	id = strchr(spec, ':');
+	if (!id)
+		return 0;
+
+	speclen = id - spec;
+	id++;
+
+	/* Anything after here requires a partial match on the ID string */
+	kid = asymmetric_key_id(key);
+	if (!kid)
+		return 0;
+
+	idlen = strlen(id);
+	kidlen = strlen(kid);
+	if (idlen > kidlen)
+		return 0;
+
+	kid += kidlen - idlen;
+	if (strcasecmp(id, kid) != 0)
+		return 0;
+
+	if (speclen == 2 &&
+	    memcmp(spec, "id", 2) == 0)
+		return 1;
+
+	if (speclen == subtype->name_len &&
+	    memcmp(spec, subtype->name, speclen) == 0)
+		return 1;
+
+	return 0;
+}
+
+/*
+ * 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 char *kid = asymmetric_key_id(key);
+	size_t n;
+
+	seq_puts(m, key->description);
+
+	if (subtype) {
+		seq_puts(m, ": ");
+		subtype->describe(key, m);
+
+		if (kid) {
+			seq_putc(m, ' ');
+			n = strlen(kid);
+			if (n <= 8)
+				seq_puts(m, kid);
+			else
+				seq_puts(m, kid + n - 8);
+		}
+
+		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];
+
+	pr_devel("==>%s()\n", __func__);
+
+	if (subtype) {
+		subtype->destroy(prep->payload);
+		module_put(subtype->owner);
+	}
+	kfree(prep->type_data[1]);
+	kfree(prep->description);
+}
+
+/*
+ * Instantiate a asymmetric_key defined key.  The key was preparsed, so we just
+ * have to transfer the data here.
+ */
+static int asymmetric_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
+{
+	int ret;
+
+	pr_devel("==>%s()\n", __func__);
+
+	ret = key_payload_reserve(key, prep->quotalen);
+	if (ret == 0) {
+		key->type_data.p[0] = prep->type_data[0];
+		key->type_data.p[1] = prep->type_data[1];
+		key->payload.data = prep->payload;
+		prep->type_data[0] = NULL;
+		prep->type_data[1] = NULL;
+		prep->payload = NULL;
+	}
+	pr_devel("<==%s() = %d\n", __func__, ret);
+	return ret;
+}
+
+/*
+ * 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);
+	if (subtype) {
+		subtype->destroy(key->payload.data);
+		module_put(subtype->owner);
+		key->type_data.p[0] = NULL;
+	}
+	kfree(key->type_data.p[1]);
+	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	= asymmetric_key_instantiate,
+	.match		= asymmetric_key_match,
+	.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/public_key.c

@@ -0,0 +1,108 @@
+/* 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[PKEY_ALGO__LAST] = {
+	[PKEY_ALGO_DSA]		= "DSA",
+	[PKEY_ALGO_RSA]		= "RSA",
+};
+EXPORT_SYMBOL_GPL(pkey_algo);
+
+const char *const pkey_hash_algo[PKEY_HASH__LAST] = {
+	[PKEY_HASH_MD4]		= "md4",
+	[PKEY_HASH_MD5]		= "md5",
+	[PKEY_HASH_SHA1]	= "sha1",
+	[PKEY_HASH_RIPE_MD_160]	= "rmd160",
+	[PKEY_HASH_SHA256]	= "sha256",
+	[PKEY_HASH_SHA384]	= "sha384",
+	[PKEY_HASH_SHA512]	= "sha512",
+	[PKEY_HASH_SHA224]	= "sha224",
+};
+EXPORT_SYMBOL_GPL(pkey_hash_algo);
+
+const char *const pkey_id_type[PKEY_ID_TYPE__LAST] = {
+	[PKEY_ID_PGP]		= "PGP",
+	[PKEY_ID_X509]		= "X509",
+};
+EXPORT_SYMBOL_GPL(pkey_id_type);
+
+/*
+ * 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[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.
+ */
+static int public_key_verify_signature(const struct key *key,
+				       const struct public_key_signature *sig)
+{
+	const struct public_key *pk = key->payload.data;
+
+	if (!pk->algo->verify_signature)
+		return -ENOTSUPP;
+
+	if (sig->nr_mpi != pk->algo->n_sig_mpi) {
+		pr_debug("Signature has %u MPI not %u\n",
+			 sig->nr_mpi, pk->algo->n_sig_mpi);
+		return -EINVAL;
+	}
+
+	return pk->algo->verify_signature(pk, sig);
+}
+
+/*
+ * Public key algorithm asymmetric key subtype
+ */
+struct asymmetric_key_subtype public_key_subtype = {
+	.owner			= THIS_MODULE,
+	.name			= "public_key",
+	.describe		= public_key_describe,
+	.destroy		= public_key_destroy,
+	.verify_signature	= public_key_verify_signature,
+};
+EXPORT_SYMBOL_GPL(public_key_subtype);

crypto/asymmetric_keys/public_key.h

@@ -0,0 +1,30 @@
+/* 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;

crypto/asymmetric_keys/rsa.c

@@ -0,0 +1,277 @@
+/* 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 "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) }
+	[PKEY_HASH_MD5]		= _(MD5),
+	[PKEY_HASH_SHA1]	= _(SHA1),
+	[PKEY_HASH_RIPE_MD_160]	= _(RIPE_MD_160),
+	[PKEY_HASH_SHA256]	= _(SHA256),
+	[PKEY_HASH_SHA384]	= _(SHA384),
+	[PKEY_HASH_SHA512]	= _(SHA512),
+	[PKEY_HASH_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 (memcmp(asn1_template, EM + T_offset, asn1_size) != 0) {
+		kleave(" = -EBADMSG [EM[T] ASN.1 mismatch]");
+		return -EBADMSG;
+	}
+
+	if (memcmp(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 +1,49 @@
+/* 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.
+ */
+
+#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/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,
+	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 +1,535 @@
+/* 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/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->fingerprint);
+		kfree(cert->authority);
+		kfree(cert);
+	}
+}
+
+/*
+ * 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;
+	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;
+
+	kfree(ctx);
+	return cert;
+
+error_decode:
+	kfree(ctx);
+error_no_ctx:
+	x509_free_certificate(cert);
+error_no_cert:
+	return ERR_PTR(ret);
+}
+
+/*
+ * 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_hash_algo = PKEY_HASH_MD5;
+		ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
+		break;
+
+	case OID_sha1WithRSAEncryption:
+		ctx->cert->sig_hash_algo = PKEY_HASH_SHA1;
+		ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
+		break;
+
+	case OID_sha256WithRSAEncryption:
+		ctx->cert->sig_hash_algo = PKEY_HASH_SHA256;
+		ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
+		break;
+
+	case OID_sha384WithRSAEncryption:
+		ctx->cert->sig_hash_algo = PKEY_HASH_SHA384;
+		ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
+		break;
+
+	case OID_sha512WithRSAEncryption:
+		ctx->cert->sig_hash_algo = PKEY_HASH_SHA512;
+		ctx->cert->sig_pkey_algo = PKEY_ALGO_RSA;
+		break;
+
+	case OID_sha224WithRSAEncryption:
+		ctx->cert->sig_hash_algo = PKEY_HASH_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->sig = value;
+	ctx->cert->sig_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;
+	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;
+	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;
+
+	/* There seems to be an extraneous 0 byte on the front of the data */
+	ctx->cert->pkey_algo = PKEY_ALGO_RSA;
+	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;
+	const unsigned char *v = value;
+	char *f;
+	int i;
+
+	pr_debug("Extension: %u\n", ctx->last_oid);
+
+	if (ctx->last_oid == OID_subjectKeyIdentifier) {
+		/* Get hold of the key fingerprint */
+		if (vlen < 3)
+			return -EBADMSG;
+		if (v[0] != ASN1_OTS || v[1] != vlen - 2)
+			return -EBADMSG;
+		v += 2;
+		vlen -= 2;
+
+		f = kmalloc(vlen * 2 + 1, GFP_KERNEL);
+		if (!f)
+			return -ENOMEM;
+		for (i = 0; i < vlen; i++)
+			sprintf(f + i * 2, "%02x", v[i]);
+		pr_debug("fingerprint %s\n", f);
+		ctx->cert->fingerprint = f;
+		return 0;
+	}
+
+	if (ctx->last_oid == OID_authorityKeyIdentifier) {
+		size_t key_len;
+
+		/* Get hold of the CA key fingerprint */
+		if (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;
+
+			key_len = 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;
+
+			key_len = v[sub + 1];
+			v += (sub + 2);
+		}
+
+		f = kmalloc(key_len * 2 + 1, GFP_KERNEL);
+		if (!f)
+			return -ENOMEM;
+		for (i = 0; i < key_len; i++)
+			sprintf(f + i * 2, "%02x", v[i]);
+		pr_debug("authority   %s\n", f);
+		ctx->cert->authority = f;
+		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 +1,36 @@
+/* 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 <crypto/public_key.h>
+
+struct x509_certificate {
+	struct x509_certificate *next;
+	struct public_key *pub;			/* Public key details */
+	char		*issuer;		/* Name of certificate issuer */
+	char		*subject;		/* Name of certificate subject */
+	char		*fingerprint;		/* Key fingerprint as hex */
+	char		*authority;		/* Authority key fingerprint as hex */
+	struct tm	valid_from;
+	struct tm	valid_to;
+	enum pkey_algo	pkey_algo : 8;		/* Public key algorithm */
+	enum pkey_algo	sig_pkey_algo : 8;	/* Signature public key algorithm */
+	enum pkey_hash_algo sig_hash_algo : 8;	/* Signature hash algorithm */
+	const void	*tbs;			/* Signed data */
+	size_t		tbs_size;		/* Size of signed data */
+	const void	*sig;			/* Signature data */
+	size_t		sig_size;		/* Size of sigature */
+};
+
+/*
+ * 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);

crypto/asymmetric_keys/x509_public_key.c

@@ -0,0 +1,201 @@
+/* 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 <crypto/hash.h>
+#include "asymmetric_keys.h"
+#include "public_key.h"
+#include "x509_parser.h"
+
+static const
+struct public_key_algorithm *x509_public_key_algorithms[PKEY_ALGO__LAST] = {
+	[PKEY_ALGO_DSA]		= NULL,
+#if defined(CONFIG_PUBLIC_KEY_ALGO_RSA) || \
+	defined(CONFIG_PUBLIC_KEY_ALGO_RSA_MODULE)
+	[PKEY_ALGO_RSA]		= &RSA_public_key_algorithm,
+#endif
+};
+
+/*
+ * Check the signature on a certificate using the provided public key
+ */
+static int x509_check_signature(const struct public_key *pub,
+				const struct x509_certificate *cert)
+{
+	struct public_key_signature *sig;
+	struct crypto_shash *tfm;
+	struct shash_desc *desc;
+	size_t digest_size, desc_size;
+	int ret;
+
+	pr_devel("==>%s()\n", __func__);
+	
+	/* Allocate the hashing algorithm we're going to need and find out how
+	 * big the hash operational data will be.
+	 */
+	tfm = crypto_alloc_shash(pkey_hash_algo[cert->sig_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);
+	digest_size = crypto_shash_digestsize(tfm);
+
+	/* We allocate the hash operational data storage on the end of our
+	 * context data.
+	 */
+	ret = -ENOMEM;
+	sig = kzalloc(sizeof(*sig) + desc_size + digest_size, GFP_KERNEL);
+	if (!sig)
+		goto error_no_sig;
+
+	sig->pkey_hash_algo	= cert->sig_hash_algo;
+	sig->digest		= (u8 *)sig + sizeof(*sig) + desc_size;
+	sig->digest_size	= digest_size;
+
+	desc = (void *)sig + sizeof(*sig);
+	desc->tfm	= tfm;
+	desc->flags	= CRYPTO_TFM_REQ_MAY_SLEEP;
+
+	ret = crypto_shash_init(desc);
+	if (ret < 0)
+		goto error;
+
+	ret = -ENOMEM;
+	sig->rsa.s = mpi_read_raw_data(cert->sig, cert->sig_size);
+	if (!sig->rsa.s)
+		goto error;
+
+	ret = crypto_shash_finup(desc, cert->tbs, cert->tbs_size, sig->digest);
+	if (ret < 0)
+		goto error_mpi;
+
+	ret = pub->algo->verify_signature(pub, sig);
+
+	pr_debug("Cert Verification: %d\n", ret);
+
+error_mpi:
+	mpi_free(sig->rsa.s);
+error:
+	kfree(sig);
+error_no_sig:
+	crypto_free_shash(tfm);
+
+	pr_devel("<==%s() = %d\n", __func__, ret);
+	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 x509_certificate *cert;
+	size_t srlen, sulen;
+	char *desc = NULL;
+	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);
+	pr_devel("Cert Key Algo: %s\n", pkey_algo[cert->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[cert->sig_pkey_algo],
+		 pkey_hash_algo[cert->sig_hash_algo]);
+
+	if (!cert->fingerprint || !cert->authority) {
+		pr_warn("Cert for '%s' must have SubjKeyId and AuthKeyId extensions\n",
+			cert->subject);
+		ret = -EKEYREJECTED;
+		goto error_free_cert;
+	}
+
+	cert->pub->algo = x509_public_key_algorithms[cert->pkey_algo];
+	cert->pub->id_type = PKEY_ID_X509;
+
+	/* Check the signature on the key */
+	if (strcmp(cert->fingerprint, cert->authority) == 0) {
+		ret = x509_check_signature(cert->pub, cert);
+		if (ret < 0)
+			goto error_free_cert;
+	}
+
+	/* Propose a description */
+	sulen = strlen(cert->subject);
+	srlen = strlen(cert->fingerprint);
+	ret = -ENOMEM;
+	desc = kmalloc(sulen + 2 + srlen + 1, GFP_KERNEL);
+	if (!desc)
+		goto error_free_cert;
+	memcpy(desc, cert->subject, sulen);
+	desc[sulen] = ':';
+	desc[sulen + 1] = ' ';
+	memcpy(desc + sulen + 2, cert->fingerprint, srlen);
+	desc[sulen + 2 + srlen] = 0;
+
+	/* 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] = cert->fingerprint;
+	prep->payload = cert->pub;
+	prep->description = desc;
+	prep->quotalen = 100;
+
+	/* We've finished with the certificate */
+	cert->pub = NULL;
+	cert->fingerprint = NULL;
+	desc = NULL;
+	ret = 0;
+
+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);

crypto/asymmetric_keys/x509_rsakey.asn1

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