[deliverable/linux.git] / crypto / asymmetric_keys / x509_public_key.c

/* 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 struct {
	struct asymmetric_key_id id;
	unsigned char data[10];
} cakey;

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 = &cakey.id;
		size_t hexlen = (strlen(str) - 3) / 2;
		int ret;

		if (hexlen == 0 || hexlen > sizeof(cakey.data)) {
			pr_err("Missing or invalid ca_keys id\n");
			return 1;
		}

		ret = __asymmetric_key_hex_to_key_id(str + 3, p, hexlen);
		if (ret < 0)
			pr_err("Unparsable ca_keys id hex string\n");
		else
			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.
 * @id: The issuer & serialNumber to look for or NULL.
 * @skid: The subjectKeyIdentifier to look for or NULL.
 * @partial: Use partial match if true, exact if false.
 *
 * Find a key in the given keyring by identifier.  The preferred identifier is
 * the issuer + serialNumber and the fallback identifier is the
 * subjectKeyIdentifier.  If both are given, the lookup is by the former, but
 * the latter must also match.
 */
struct key *x509_request_asymmetric_key(struct key *keyring,
					const struct asymmetric_key_id *id,
					const struct asymmetric_key_id *skid,
					bool partial)
{
	struct key *key;
	key_ref_t ref;
	const char *lookup;
	char *req, *p;
	int len;

	if (id) {
		lookup = id->data;
		len = id->len;
	} else {
		lookup = skid->data;
		len = skid->len;
	}
	
	/* Construct an identifier "id:<keyid>". */
	p = req = kmalloc(2 + 1 + len * 2 + 1, GFP_KERNEL);
	if (!req)
		return ERR_PTR(-ENOMEM);

	if (partial) {
		*p++ = 'i';
		*p++ = 'd';
	} else {
		*p++ = 'e';
		*p++ = 'x';
	}
	*p++ = ':';
	p = bin2hex(p, lookup, len);
	*p = 0;

	pr_debug("Look up: \"%s\"\n", req);

	ref = keyring_search(make_key_ref(keyring, 1),
			     &key_type_asymmetric, req);
	if (IS_ERR(ref))
		pr_debug("Request for key '%s' err %ld\n", req, PTR_ERR(ref));
	kfree(req);

	if (IS_ERR(ref)) {
		switch (PTR_ERR(ref)) {
			/* Hide some search errors */
		case -EACCES:
		case -ENOTDIR:
		case -EAGAIN:
			return ERR_PTR(-ENOKEY);
		default:
			return ERR_CAST(ref);
		}
	}

	key = key_ref_to_ptr(ref);
	if (id && skid) {
		const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
		if (!kids->id[1]) {
			pr_debug("issuer+serial match, but expected SKID missing\n");
			goto reject;
		}
		if (!asymmetric_key_id_same(skid, kids->id[1])) {
			pr_debug("issuer+serial match, but SKID does not\n");
			goto reject;
		}
	}
	
	pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key));
	return key;

reject:
	key_put(key);
	return ERR_PTR(-EKEYREJECTED);
}
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(ALIGN(digest_size, __alignof__(*desc)) + desc_size,
			 GFP_KERNEL);
	if (!digest)
		goto error;

	cert->sig.digest = digest;
	cert->sig.digest_size = digest_size;

	desc = PTR_ALIGN(digest + digest_size, __alignof__(*desc));
	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->akid_skid, ca_keyid))
		return -EPERM;

	key = x509_request_asymmetric_key(trust_keyring,
					  cert->akid_id, cert->akid_skid,
					  false);
	if (!IS_ERR(key))  {
		if (!use_builtin_keys
		    || test_bit(KEY_FLAG_BUILTIN, &key->flags))
			ret = x509_check_signature(key->payload.data[asym_crypto],
						   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 period: %lld-%lld\n", cert->valid_from, cert->valid_to);
	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->akid_skid && !cert->akid_id) ||
	    asymmetric_key_id_same(cert->skid, cert->akid_skid) ||
	    asymmetric_key_id_same(cert->id, cert->akid_id)) {
		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)
			ret = x509_validate_trust(cert, get_ima_mok_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;
	}

	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->payload.data[asym_subtype] = &public_key_subtype;
	prep->payload.data[asym_key_ids] = kids;
	prep->payload.data[asym_crypto] = 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");
Commit	Line	Data
c26fd69f DH	1	/* Instantiate a public key crypto key from an X.509 Certificate
	2	*
	3	* Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public Licence
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the Licence, or (at your option) any later version.
	10	*/
	11
	12	#define pr_fmt(fmt) "X.509: "fmt
	13	#include <linux/module.h>
	14	#include <linux/kernel.h>
	15	#include <linux/slab.h>
	16	#include <linux/err.h>
	17	#include <linux/mpi.h>
	18	#include <linux/asn1_decoder.h>
	19	#include <keys/asymmetric-subtype.h>
	20	#include <keys/asymmetric-parser.h>
3be4beaf	21	#include <keys/system_keyring.h>
c26fd69f DH	22	#include <crypto/hash.h>
	23	#include "asymmetric_keys.h"
	24	#include "public_key.h"
	25	#include "x509_parser.h"
	26
32c4741c	27	static bool use_builtin_keys;
46963b77	28	static struct asymmetric_key_id *ca_keyid;
ffb70f61 DK	29
ffb70f61 DK	30	#ifndef MODULE
f2b3dee4 MZ	31	static struct {
	32	struct asymmetric_key_id id;
	33	unsigned char data[10];
	34	} cakey;
	35
ffb70f61 DK	36	static int __init ca_keys_setup(char *str)
	37	{
	38	if (!str) /* default system keyring */
	39	return 1;
	40
46963b77	41	if (strncmp(str, "id:", 3) == 0) {
f2b3dee4 MZ	42	struct asymmetric_key_id *p = &cakey.id;
	43	size_t hexlen = (strlen(str) - 3) / 2;
	44	int ret;
	45
	46	if (hexlen == 0 \|\| hexlen > sizeof(cakey.data)) {
	47	pr_err("Missing or invalid ca_keys id\n");
	48	return 1;
	49	}
	50
	51	ret = __asymmetric_key_hex_to_key_id(str + 3, p, hexlen);
	52	if (ret < 0)
	53	pr_err("Unparsable ca_keys id hex string\n");
	54	else
46963b77 DH	55	ca_keyid = p; /* owner key 'id:xxxxxx' */
46963b77 DH	56	} else if (strcmp(str, "builtin") == 0) {
32c4741c	57	use_builtin_keys = true;
46963b77	58	}
ffb70f61 DK	59
	60	return 1;
	61	}
	62	__setup("ca_keys=", ca_keys_setup);
	63	#endif
	64
5ce43ad2 DH	65	/**
	66	* x509_request_asymmetric_key - Request a key by X.509 certificate params.
	67	* @keyring: The keys to search.
4573b64a DH	68	* @id: The issuer & serialNumber to look for or NULL.
4573b64a DH	69	* @skid: The subjectKeyIdentifier to look for or NULL.
f1b731db	70	* @partial: Use partial match if true, exact if false.
5ce43ad2	71	*
4573b64a DH	72	* Find a key in the given keyring by identifier. The preferred identifier is
	73	* the issuer + serialNumber and the fallback identifier is the
	74	* subjectKeyIdentifier. If both are given, the lookup is by the former, but
	75	* the latter must also match.
3be4beaf	76	*/
5ce43ad2	77	struct key x509_request_asymmetric_key(struct key keyring,
4573b64a DH	78	const struct asymmetric_key_id *id,
4573b64a DH	79	const struct asymmetric_key_id *skid,
f1b731db	80	bool partial)
3be4beaf	81	{
4573b64a DH	82	struct key *key;
	83	key_ref_t ref;
	84	const char *lookup;
	85	char req, p;
	86	int len;
	87
	88	if (id) {
	89	lookup = id->data;
	90	len = id->len;
	91	} else {
	92	lookup = skid->data;
	93	len = skid->len;
	94	}
	95
46963b77	96	/* Construct an identifier "id:<keyid>". */
4573b64a DH	97	p = req = kmalloc(2 + 1 + len * 2 + 1, GFP_KERNEL);
4573b64a DH	98	if (!req)
3be4beaf MZ	99	return ERR_PTR(-ENOMEM);
3be4beaf MZ	100
f1b731db DK	101	if (partial) {
	102	*p++ = 'i';
	103	*p++ = 'd';
	104	} else {
	105	*p++ = 'e';
	106	*p++ = 'x';
	107	}
46963b77	108	*p++ = ':';
4573b64a	109	p = bin2hex(p, lookup, len);
46963b77	110	*p = 0;
3be4beaf	111
4573b64a	112	pr_debug("Look up: \"%s\"\n", req);
3be4beaf	113
4573b64a DH	114	ref = keyring_search(make_key_ref(keyring, 1),
	115	&key_type_asymmetric, req);
	116	if (IS_ERR(ref))
	117	pr_debug("Request for key '%s' err %ld\n", req, PTR_ERR(ref));
	118	kfree(req);
3be4beaf	119
4573b64a DH	120	if (IS_ERR(ref)) {
4573b64a DH	121	switch (PTR_ERR(ref)) {
3be4beaf MZ	122	/* Hide some search errors */
	123	case -EACCES:
	124	case -ENOTDIR:
	125	case -EAGAIN:
	126	return ERR_PTR(-ENOKEY);
	127	default:
4573b64a DH	128	return ERR_CAST(ref);
	129	}
	130	}
	131
	132	key = key_ref_to_ptr(ref);
	133	if (id && skid) {
	134	const struct asymmetric_key_ids *kids = asymmetric_key_ids(key);
	135	if (!kids->id[1]) {
	136	pr_debug("issuer+serial match, but expected SKID missing\n");
	137	goto reject;
	138	}
	139	if (!asymmetric_key_id_same(skid, kids->id[1])) {
	140	pr_debug("issuer+serial match, but SKID does not\n");
	141	goto reject;
3be4beaf MZ	142	}
3be4beaf MZ	143	}
4573b64a DH	144
	145	pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key));
	146	return key;
3be4beaf	147
4573b64a DH	148	reject:
	149	key_put(key);
	150	return ERR_PTR(-EKEYREJECTED);
3be4beaf	151	}
cf5b50fd	152	EXPORT_SYMBOL_GPL(x509_request_asymmetric_key);
3be4beaf	153
c26fd69f	154	/*
b426beb6 DH	155	* Set up the signature parameters in an X.509 certificate. This involves
b426beb6 DH	156	* digesting the signed data and extracting the signature.
c26fd69f	157	*/
b426beb6	158	int x509_get_sig_params(struct x509_certificate *cert)
c26fd69f	159	{
c26fd69f DH	160	struct crypto_shash *tfm;
	161	struct shash_desc *desc;
	162	size_t digest_size, desc_size;
b426beb6	163	void *digest;
c26fd69f DH	164	int ret;
	165
	166	pr_devel("==>%s()\n", __func__);
b426beb6	167
41559420 DH	168	if (cert->unsupported_crypto)
41559420 DH	169	return -ENOPKG;
b426beb6 DH	170	if (cert->sig.rsa.s)
	171	return 0;
	172
	173	cert->sig.rsa.s = mpi_read_raw_data(cert->raw_sig, cert->raw_sig_size);
	174	if (!cert->sig.rsa.s)
	175	return -ENOMEM;
	176	cert->sig.nr_mpi = 1;
	177
c26fd69f DH	178	/* Allocate the hashing algorithm we're going to need and find out how
	179	* big the hash operational data will be.
	180	*/
3fe78ca2	181	tfm = crypto_alloc_shash(hash_algo_name[cert->sig.pkey_hash_algo], 0, 0);
41559420 DH	182	if (IS_ERR(tfm)) {
	183	if (PTR_ERR(tfm) == -ENOENT) {
	184	cert->unsupported_crypto = true;
	185	return -ENOPKG;
	186	}
	187	return PTR_ERR(tfm);
	188	}
c26fd69f DH	189
	190	desc_size = crypto_shash_descsize(tfm) + sizeof(*desc);
	191	digest_size = crypto_shash_digestsize(tfm);
	192
b426beb6 DH	193	/* We allocate the hash operational data storage on the end of the
b426beb6 DH	194	* digest storage space.
c26fd69f DH	195	*/
c26fd69f DH	196	ret = -ENOMEM;
271817a3 SV	197	digest = kzalloc(ALIGN(digest_size, __alignof__(*desc)) + desc_size,
271817a3 SV	198	GFP_KERNEL);
b426beb6 DH	199	if (!digest)
b426beb6 DH	200	goto error;
c26fd69f	201
b426beb6 DH	202	cert->sig.digest = digest;
b426beb6 DH	203	cert->sig.digest_size = digest_size;
c26fd69f	204
271817a3	205	desc = PTR_ALIGN(digest + digest_size, __alignof__(*desc));
b426beb6 DH	206	desc->tfm = tfm;
b426beb6 DH	207	desc->flags = CRYPTO_TFM_REQ_MAY_SLEEP;
c26fd69f DH	208
	209	ret = crypto_shash_init(desc);
	210	if (ret < 0)
	211	goto error;
b426beb6 DH	212	might_sleep();
	213	ret = crypto_shash_finup(desc, cert->tbs, cert->tbs_size, digest);
	214	error:
	215	crypto_free_shash(tfm);
	216	pr_devel("<==%s() = %d\n", __func__, ret);
	217	return ret;
	218	}
	219	EXPORT_SYMBOL_GPL(x509_get_sig_params);
c26fd69f	220
b426beb6 DH	221	/*
	222	* Check the signature on a certificate using the provided public key
	223	*/
	224	int x509_check_signature(const struct public_key *pub,
	225	struct x509_certificate *cert)
	226	{
	227	int ret;
c26fd69f	228
b426beb6	229	pr_devel("==>%s()\n", __func__);
c26fd69f	230
b426beb6 DH	231	ret = x509_get_sig_params(cert);
	232	if (ret < 0)
	233	return ret;
c26fd69f	234
b426beb6	235	ret = public_key_verify_signature(pub, &cert->sig);
41559420 DH	236	if (ret == -ENOPKG)
41559420 DH	237	cert->unsupported_crypto = true;
c26fd69f	238	pr_debug("Cert Verification: %d\n", ret);
c26fd69f DH	239	return ret;
c26fd69f DH	240	}
b426beb6	241	EXPORT_SYMBOL_GPL(x509_check_signature);
c26fd69f	242
3be4beaf MZ	243	/*
	244	* Check the new certificate against the ones in the trust keyring. If one of
	245	* those is the signing key and validates the new certificate, then mark the
	246	* new certificate as being trusted.
	247	*
	248	* Return 0 if the new certificate was successfully validated, 1 if we couldn't
	249	* find a matching parent certificate in the trusted list and an error if there
	250	* is a matching certificate but the signature check fails.
	251	*/
	252	static int x509_validate_trust(struct x509_certificate *cert,
	253	struct key *trust_keyring)
	254	{
3be4beaf MZ	255	struct key *key;
	256	int ret = 1;
	257
	258	if (!trust_keyring)
	259	return -EOPNOTSUPP;
	260
b92e6570	261	if (ca_keyid && !asymmetric_key_id_partial(cert->akid_skid, ca_keyid))
ffb70f61 DK	262	return -EPERM;
ffb70f61 DK	263
4573b64a DH	264	key = x509_request_asymmetric_key(trust_keyring,
4573b64a DH	265	cert->akid_id, cert->akid_skid,
f1b731db	266	false);
3be4beaf	267	if (!IS_ERR(key)) {
32c4741c DK	268	if (!use_builtin_keys
32c4741c DK	269	\|\| test_bit(KEY_FLAG_BUILTIN, &key->flags))
146aa8b1 DH	270	ret = x509_check_signature(key->payload.data[asym_crypto],
146aa8b1 DH	271	cert);
3be4beaf MZ	272	key_put(key);
	273	}
	274	return ret;
	275	}
	276
c26fd69f DH	277	/*
	278	* Attempt to parse a data blob for a key as an X509 certificate.
	279	*/
	280	static int x509_key_preparse(struct key_preparsed_payload *prep)
	281	{
46963b77	282	struct asymmetric_key_ids *kids;
c26fd69f	283	struct x509_certificate *cert;
46963b77	284	const char *q;
c26fd69f	285	size_t srlen, sulen;
46963b77	286	char desc = NULL, p;
c26fd69f DH	287	int ret;
	288
	289	cert = x509_cert_parse(prep->data, prep->datalen);
	290	if (IS_ERR(cert))
	291	return PTR_ERR(cert);
	292
	293	pr_devel("Cert Issuer: %s\n", cert->issuer);
	294	pr_devel("Cert Subject: %s\n", cert->subject);
2ecdb23b DH	295
	296	if (cert->pub->pkey_algo >= PKEY_ALGO__LAST \|\|
	297	cert->sig.pkey_algo >= PKEY_ALGO__LAST \|\|
	298	cert->sig.pkey_hash_algo >= PKEY_HASH__LAST \|\|
	299	!pkey_algo[cert->pub->pkey_algo] \|\|
	300	!pkey_algo[cert->sig.pkey_algo] \|\|
3fe78ca2	301	!hash_algo_name[cert->sig.pkey_hash_algo]) {
2ecdb23b DH	302	ret = -ENOPKG;
	303	goto error_free_cert;
	304	}
	305
67f7d60b	306	pr_devel("Cert Key Algo: %s\n", pkey_algo_name[cert->pub->pkey_algo]);
fd19a3d1	307	pr_devel("Cert Valid period: %lld-%lld\n", cert->valid_from, cert->valid_to);
c7c8bb23 DK	308	pr_devel("Cert Signature: %s + %s\n",
c7c8bb23 DK	309	pkey_algo_name[cert->sig.pkey_algo],
3fe78ca2	310	hash_algo_name[cert->sig.pkey_hash_algo]);
c26fd69f	311
67f7d60b	312	cert->pub->algo = pkey_algo[cert->pub->pkey_algo];
c26fd69f DH	313	cert->pub->id_type = PKEY_ID_X509;
c26fd69f DH	314
17334cab	315	/* Check the signature on the key if it appears to be self-signed */
4573b64a DH	316	if ((!cert->akid_skid && !cert->akid_id) \|\|
	317	asymmetric_key_id_same(cert->skid, cert->akid_skid) \|\|
	318	asymmetric_key_id_same(cert->id, cert->akid_id)) {
3be4beaf	319	ret = x509_check_signature(cert->pub, cert); /* self-signed */
c26fd69f DH	320	if (ret < 0)
c26fd69f DH	321	goto error_free_cert;
3be4beaf MZ	322	} else if (!prep->trusted) {
3be4beaf MZ	323	ret = x509_validate_trust(cert, get_system_trusted_keyring());
41c89b64 PM	324	if (ret)
41c89b64 PM	325	ret = x509_validate_trust(cert, get_ima_mok_keyring());
3be4beaf MZ	326	if (!ret)
3be4beaf MZ	327	prep->trusted = 1;
c26fd69f DH	328	}
	329
	330	/* Propose a description */
	331	sulen = strlen(cert->subject);
dd2f6c44 DH	332	if (cert->raw_skid) {
	333	srlen = cert->raw_skid_size;
	334	q = cert->raw_skid;
	335	} else {
	336	srlen = cert->raw_serial_size;
	337	q = cert->raw_serial;
	338	}
46963b77	339
c26fd69f	340	ret = -ENOMEM;
46963b77	341	desc = kmalloc(sulen + 2 + srlen * 2 + 1, GFP_KERNEL);
c26fd69f DH	342	if (!desc)
c26fd69f DH	343	goto error_free_cert;
46963b77 DH	344	p = memcpy(desc, cert->subject, sulen);
	345	p += sulen;
	346	*p++ = ':';
	347	*p++ = ' ';
	348	p = bin2hex(p, q, srlen);
	349	*p = 0;
	350
	351	kids = kmalloc(sizeof(struct asymmetric_key_ids), GFP_KERNEL);
	352	if (!kids)
	353	goto error_free_desc;
	354	kids->id[0] = cert->id;
	355	kids->id[1] = cert->skid;
c26fd69f DH	356
	357	/* We're pinning the module by being linked against it */
	358	__module_get(public_key_subtype.owner);
146aa8b1 DH	359	prep->payload.data[asym_subtype] = &public_key_subtype;
	360	prep->payload.data[asym_key_ids] = kids;
	361	prep->payload.data[asym_crypto] = cert->pub;
c26fd69f DH	362	prep->description = desc;
	363	prep->quotalen = 100;
	364
	365	/* We've finished with the certificate */
	366	cert->pub = NULL;
46963b77 DH	367	cert->id = NULL;
46963b77 DH	368	cert->skid = NULL;
c26fd69f DH	369	desc = NULL;
	370	ret = 0;
	371
46963b77 DH	372	error_free_desc:
46963b77 DH	373	kfree(desc);
c26fd69f DH	374	error_free_cert:
	375	x509_free_certificate(cert);
	376	return ret;
	377	}
	378
	379	static struct asymmetric_key_parser x509_key_parser = {
	380	.owner = THIS_MODULE,
	381	.name = "x509",
	382	.parse = x509_key_preparse,
	383	};
	384
	385	/*
	386	* Module stuff
	387	*/
	388	static int __init x509_key_init(void)
	389	{
	390	return register_asymmetric_key_parser(&x509_key_parser);
	391	}
	392
	393	static void __exit x509_key_exit(void)
	394	{
	395	unregister_asymmetric_key_parser(&x509_key_parser);
	396	}
	397
	398	module_init(x509_key_init);
	399	module_exit(x509_key_exit);
e19aaa7d KK	400
	401	MODULE_DESCRIPTION("X.509 certificate parser");
	402	MODULE_LICENSE("GPL");