/lib/hdb/common.c

/*
 * Copyright (c) 1997-2002 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "krb5_locl.h"
#include "hdb_locl.h"

int
hdb_principal2key(krb5_context context, krb5_const_principal p, krb5_data *key)
{
    Principal new;
    size_t len = 0;
    int ret;

    ret = copy_Principal(p, &new);
    if(ret)
	return ret;
    new.name.name_type = 0;

    ASN1_MALLOC_ENCODE(Principal, key->data, key->length, &new, &len, ret);
    if (ret == 0 && key->length != len)
	krb5_abortx(context, "internal asn.1 encoder error");
    free_Principal(&new);
    return ret;
}

int
hdb_key2principal(krb5_context context, krb5_data *key, krb5_principal p)
{
    return decode_Principal(key->data, key->length, p, NULL);
}

int
hdb_entry2value(krb5_context context, const hdb_entry *ent, krb5_data *value)
{
    size_t len = 0;
    int ret;

    ASN1_MALLOC_ENCODE(hdb_entry, value->data, value->length, ent, &len, ret);
    if (ret == 0 && value->length != len)
	krb5_abortx(context, "internal asn.1 encoder error");
    return ret;
}

int
hdb_value2entry(krb5_context context, krb5_data *value, hdb_entry *ent)
{
    return decode_hdb_entry(value->data, value->length, ent, NULL);
}

int
hdb_entry_alias2value(krb5_context context,
		      const hdb_entry_alias *alias,
		      krb5_data *value)
{
    size_t len = 0;
    int ret;

    ASN1_MALLOC_ENCODE(hdb_entry_alias, value->data, value->length,
		       alias, &len, ret);
    if (ret == 0 && value->length != len)
	krb5_abortx(context, "internal asn.1 encoder error");
    return ret;
}

int
hdb_value2entry_alias(krb5_context context, krb5_data *value,
		      hdb_entry_alias *ent)
{
    return decode_hdb_entry_alias(value->data, value->length, ent, NULL);
}

/*
 * Some old databases may not have stored the salt with each key, which will
 * break clients when aliases or canonicalization are used. Generate a
 * default salt based on the real principal name in the entry to handle
 * this case.
 */
static krb5_error_code
add_default_salts(krb5_context context, HDB *db, hdb_entry *entry)
{
    krb5_error_code ret;
    size_t i;
    krb5_salt pwsalt;

    ret = krb5_get_pw_salt(context, entry->principal, &pwsalt);
    if (ret)
	return ret;

    for (i = 0; i < entry->keys.len; i++) {
	Key *key = &entry->keys.val[i];

	if (key->salt != NULL ||
	    _krb5_enctype_requires_random_salt(context, key->key.keytype))
	    continue;

	key->salt = calloc(1, sizeof(*key->salt));
	if (key->salt == NULL) {
	    ret = krb5_enomem(context);
	    break;
	}

	key->salt->type = KRB5_PADATA_PW_SALT;

	ret = krb5_data_copy(&key->salt->salt,
			     pwsalt.saltvalue.data,
			     pwsalt.saltvalue.length);
	if (ret)
	    break;
    }

    krb5_free_salt(context, pwsalt);

    return ret;
}

krb5_error_code
_hdb_fetch_kvno(krb5_context context, HDB *db, krb5_const_principal principal,
		unsigned flags, krb5_kvno kvno, hdb_entry_ex *entry)
{
    krb5_principal enterprise_principal = NULL;
    krb5_data key, value;
    krb5_error_code ret;

    if (principal->name.name_type == KRB5_NT_ENTERPRISE_PRINCIPAL) {
	if (principal->name.name_string.len != 1) {
	    ret = KRB5_PARSE_MALFORMED;
	    krb5_set_error_message(context, ret, "malformed principal: "
				   "enterprise name with %d name components",
				   principal->name.name_string.len);
	    return ret;
	}
	ret = krb5_parse_name(context, principal->name.name_string.val[0],
			      &enterprise_principal);
	if (ret)
	    return ret;
	principal = enterprise_principal;
    }

    hdb_principal2key(context, principal, &key);
    if (enterprise_principal)
	krb5_free_principal(context, enterprise_principal);
    ret = db->hdb__get(context, db, key, &value);
    krb5_data_free(&key);
    if(ret)
	return ret;
    ret = hdb_value2entry(context, &value, &entry->entry);
    /* HDB_F_GET_ANY indicates request originated from KDC (not kadmin) */
    if (ret == ASN1_BAD_ID && (flags & (HDB_F_CANON|HDB_F_GET_ANY)) == 0) {
	krb5_data_free(&value);
	return HDB_ERR_NOENTRY;
    } else if (ret == ASN1_BAD_ID) {
	hdb_entry_alias alias;

	ret = hdb_value2entry_alias(context, &value, &alias);
	if (ret) {
	    krb5_data_free(&value);
	    return ret;
	}
	hdb_principal2key(context, alias.principal, &key);
	krb5_data_free(&value);
	free_hdb_entry_alias(&alias);

	ret = db->hdb__get(context, db, key, &value);
	krb5_data_free(&key);
	if (ret)
	    return ret;
	ret = hdb_value2entry(context, &value, &entry->entry);
	if (ret) {
	    krb5_data_free(&value);
	    return ret;
	}
    }
    krb5_data_free(&value);
    if ((flags & HDB_F_DECRYPT) && (flags & HDB_F_ALL_KVNOS)) {
	/* Decrypt the current keys */
	ret = hdb_unseal_keys(context, db, &entry->entry);
	if (ret) {
	    hdb_free_entry(context, entry);
	    return ret;
	}
	/* Decrypt the key history too */
	ret = hdb_unseal_keys_kvno(context, db, 0, flags, &entry->entry);
	if (ret) {
	    hdb_free_entry(context, entry);
	    return ret;
	}
    } else if ((flags & HDB_F_DECRYPT)) {
	if ((flags & HDB_F_KVNO_SPECIFIED) == 0 || kvno == entry->entry.kvno) {
	    /* Decrypt the current keys */
	    ret = hdb_unseal_keys(context, db, &entry->entry);
	    if (ret) {
		hdb_free_entry(context, entry);
		return ret;
	    }
	} else {
	    if ((flags & HDB_F_ALL_KVNOS))
		kvno = 0;
	    /*
	     * Find and decrypt the keys from the history that we want,
	     * and swap them with the current keys
	     */
	    ret = hdb_unseal_keys_kvno(context, db, kvno, flags, &entry->entry);
	    if (ret) {
		hdb_free_entry(context, entry);
		return ret;
	    }
	}
    }
    if ((flags & HDB_F_FOR_AS_REQ) && (flags & HDB_F_GET_CLIENT)) {
	/*
	 * Generate default salt for any principals missing one; note such
	 * principals could include those for which a random (non-password)
	 * key was generated, but given the salt will be ignored by a keytab
	 * client it doesn't hurt to include the default salt.
	 */
	ret = add_default_salts(context, db, &entry->entry);
	if (ret) {
	    hdb_free_entry(context, entry);
	    return ret;
	}
    }
    if (enterprise_principal) {
	/*
	 * Whilst Windows does not canonicalize enterprise principal names if
	 * the canonicalize flag is unset, the original specification in
	 * draft-ietf-krb-wg-kerberos-referrals-03.txt says we should.
	 */
	entry->entry.flags.force_canonicalize = 1;
    }

    return 0;
}

static krb5_error_code
hdb_remove_aliases(krb5_context context, HDB *db, krb5_data *key)
{
    const HDB_Ext_Aliases *aliases;
    krb5_error_code code;
    hdb_entry oldentry;
    krb5_data value;
    size_t i;

    code = db->hdb__get(context, db, *key, &value);
    if (code == HDB_ERR_NOENTRY)
	return 0;
    else if (code)
	return code;

    code = hdb_value2entry(context, &value, &oldentry);
    krb5_data_free(&value);
    if (code)
	return code;

    code = hdb_entry_get_aliases(&oldentry, &aliases);
    if (code || aliases == NULL) {
	free_hdb_entry(&oldentry);
	return code;
    }
    for (i = 0; i < aliases->aliases.len; i++) {
	krb5_data akey;

	code = hdb_principal2key(context, &aliases->aliases.val[i], &akey);
        if (code == 0) {
            code = db->hdb__del(context, db, akey);
            krb5_data_free(&akey);
        }
	if (code) {
	    free_hdb_entry(&oldentry);
	    return code;
	}
    }
    free_hdb_entry(&oldentry);
    return 0;
}

static krb5_error_code
hdb_add_aliases(krb5_context context, HDB *db,
		unsigned flags, hdb_entry_ex *entry)
{
    const HDB_Ext_Aliases *aliases;
    krb5_error_code code;
    krb5_data key, value;
    size_t i;

    code = hdb_entry_get_aliases(&entry->entry, &aliases);
    if (code || aliases == NULL)
	return code;

    for (i = 0; i < aliases->aliases.len; i++) {
	hdb_entry_alias entryalias;
	entryalias.principal = entry->entry.principal;

	code = hdb_entry_alias2value(context, &entryalias, &value);
	if (code)
	    return code;

	code = hdb_principal2key(context, &aliases->aliases.val[i], &key);
        if (code == 0) {
            code = db->hdb__put(context, db, flags, key, value);
            krb5_data_free(&key);
        }
	krb5_data_free(&value);
	if (code)
	    return code;
    }
    return 0;
}

static krb5_error_code
hdb_check_aliases(krb5_context context, HDB *db, hdb_entry_ex *entry)
{
    const HDB_Ext_Aliases *aliases;
    int code;
    size_t i;

    /* check if new aliases already is used */

    code = hdb_entry_get_aliases(&entry->entry, &aliases);
    if (code)
	return code;

    for (i = 0; aliases && i < aliases->aliases.len; i++) {
	hdb_entry_alias alias;
	krb5_data akey, value;

	code = hdb_principal2key(context, &aliases->aliases.val[i], &akey);
        if (code == 0) {
            code = db->hdb__get(context, db, akey, &value);
            krb5_data_free(&akey);
        }
	if (code == HDB_ERR_NOENTRY)
	    continue;
	else if (code)
	    return code;

	code = hdb_value2entry_alias(context, &value, &alias);
	krb5_data_free(&value);

	if (code == ASN1_BAD_ID)
	    return HDB_ERR_EXISTS;
	else if (code)
	    return code;

	code = krb5_principal_compare(context, alias.principal,
				      entry->entry.principal);
	free_hdb_entry_alias(&alias);
	if (code == 0)
	    return HDB_ERR_EXISTS;
    }
    return 0;
}

krb5_error_code
_hdb_store(krb5_context context, HDB *db, unsigned flags, hdb_entry_ex *entry)
{
    krb5_data key, value;
    int code;

    if (entry->entry.flags.do_not_store ||
	entry->entry.flags.force_canonicalize)
	return HDB_ERR_MISUSE;
    /* check if new aliases already is used */
    code = hdb_check_aliases(context, db, entry);
    if (code)
	return code;

    if ((flags & HDB_F_PRECHECK) && (flags & HDB_F_REPLACE))
        return 0;

    if ((flags & HDB_F_PRECHECK)) {
        code = hdb_principal2key(context, entry->entry.principal, &key);
        if (code)
            return code;
        code = db->hdb__get(context, db, key, &value);
        krb5_data_free(&key);
        if (code == 0)
            krb5_data_free(&value);
        if (code == HDB_ERR_NOENTRY)
            return 0;
        return code ? code : HDB_ERR_EXISTS;
    }

    if(entry->entry.generation == NULL) {
	struct timeval t;
	entry->entry.generation = malloc(sizeof(*entry->entry.generation));
	if(entry->entry.generation == NULL) {
	    krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
	    return ENOMEM;
	}
	gettimeofday(&t, NULL);
	entry->entry.generation->time = t.tv_sec;
	entry->entry.generation->usec = t.tv_usec;
	entry->entry.generation->gen = 0;
    } else
	entry->entry.generation->gen++;

    code = hdb_seal_keys(context, db, &entry->entry);
    if (code)
	return code;

    hdb_principal2key(context, entry->entry.principal, &key);

    /* remove aliases */
    code = hdb_remove_aliases(context, db, &key);
    if (code) {
	krb5_data_free(&key);
	return code;
    }
    hdb_entry2value(context, &entry->entry, &value);
    code = db->hdb__put(context, db, flags & HDB_F_REPLACE, key, value);
    krb5_data_free(&value);
    krb5_data_free(&key);
    if (code)
	return code;

    code = hdb_add_aliases(context, db, flags, entry);

    return code;
}

krb5_error_code
_hdb_remove(krb5_context context, HDB *db,
            unsigned flags, krb5_const_principal principal)
{
    krb5_data key, value;
    int code;

    hdb_principal2key(context, principal, &key);

    if ((flags & HDB_F_PRECHECK)) {
        /*
         * We don't check that we can delete the aliases because we
         * assume that the DB is consistent.  If we did check for alias
         * consistency we'd also have to provide a way to fsck the DB,
         * otherwise admins would have no way to recover -- papering
         * over this here is less work, but we really ought to provide
         * an HDB fsck.
         */
        code = db->hdb__get(context, db, key, &value);
        krb5_data_free(&key);
        if (code == 0) {
            krb5_data_free(&value);
            return 0;
        }
        return code;
    }

    code = hdb_remove_aliases(context, db, &key);
    if (code) {
	krb5_data_free(&key);
	return code;
    }
    code = db->hdb__del(context, db, key);
    krb5_data_free(&key);
    return code;
}