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5447b81fb1c6ec72a4dede5284bf21edd98ba65d
heimdal/lib/hdb/hdb.c
Nicolas Williams 5447b81fb1 hdb: Move virtual principals into HDB layer 
This is a large commit that adds several features:

 - Revamps and moves virtual host-based service principal functionality
   from kdc/ to lib/hdb/ so that it may be automatically visible to
   lib/kadm5/, as well as kadmin(1)/kadmind(8) and ktutil(1).

   The changes are backwards-incompatible.

 - Completes support for documenting a service principal's supported
   enctypes in its HDB entry independently of its long-term keys.  This
   will reduce HDB bloat by not requiring that service principals have
   more long-term keys than they need just to document the service's
   supported enctypes.

 - Adds support for storing krb5.conf content in principals' HDB
   entries.  This may eventually be used for causing Heimdal KDC
   services to reconfigure primary/secondary roles automatically by
   discovering the configured primary in an HDB entry for the realm.

   For now this will be used to help reduce the amount of configuration
   needed by clients of an upcoming HTTP binding of the kadmin service.
2020-09-08 00:25:36 -05:00

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/*
* Copyright (c) 1997 - 2008 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Portions Copyright (c) 2009 Apple Inc. 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"
#ifdef HAVE_DLFCN_H
#include <dlfcn.h>
#endif
/*! @mainpage Heimdal database backend library
*
* @section intro Introduction
*
* Heimdal libhdb library provides the backend support for Heimdal kdc
* and kadmind. Its here where plugins for diffrent database engines
* can be pluged in and extend support for here Heimdal get the
* principal and policy data from.
*
* Example of Heimdal backend are:
* - Berkeley DB 1.85
* - Berkeley DB 3.0
* - Berkeley DB 4.0
* - New Berkeley DB
* - LDAP
*
*
* The project web page: http://www.h5l.org/
*
*/
const int hdb_interface_version = HDB_INTERFACE_VERSION;
static struct hdb_method methods[] = {
/* "db:" should be db3 if we have db3, or db1 if we have db1 */
#if HAVE_DB3
{ HDB_INTERFACE_VERSION, NULL, NULL, "db:", hdb_db3_create},
#elif HAVE_DB1
{ HDB_INTERFACE_VERSION, NULL, NULL, "db:", hdb_db1_create},
#endif
#if HAVE_DB1
{ HDB_INTERFACE_VERSION, NULL, NULL, "db1:", hdb_db1_create},
#endif
#if HAVE_DB3
{ HDB_INTERFACE_VERSION, NULL, NULL, "db3:", hdb_db3_create},
#endif
#if HAVE_DB1
{ HDB_INTERFACE_VERSION, NULL, NULL, "mit-db:", hdb_mitdb_create},
#endif
#if HAVE_LMDB
{ HDB_INTERFACE_VERSION, NULL, NULL, "mdb:", hdb_mdb_create},
{ HDB_INTERFACE_VERSION, NULL, NULL, "lmdb:", hdb_mdb_create},
#endif
#if HAVE_NDBM
{ HDB_INTERFACE_VERSION, NULL, NULL, "ndbm:", hdb_ndbm_create},
#endif
{ HDB_INTERFACE_VERSION, NULL, NULL, "keytab:", hdb_keytab_create},
#if defined(OPENLDAP) && !defined(OPENLDAP_MODULE)
{ HDB_INTERFACE_VERSION, NULL, NULL, "ldap:", hdb_ldap_create},
{ HDB_INTERFACE_VERSION, NULL, NULL, "ldapi:", hdb_ldapi_create},
#elif defined(OPENLDAP)
{ HDB_INTERFACE_VERSION, NULL, NULL, "ldap:", NULL},
{ HDB_INTERFACE_VERSION, NULL, NULL, "ldapi:", NULL},
#endif
#ifdef HAVE_SQLITE3
{ HDB_INTERFACE_VERSION, NULL, NULL, "sqlite:", hdb_sqlite_create},
#endif
{ 0, NULL, NULL, NULL, NULL}
};
/*
* It'd be nice if we could try opening an HDB with each supported
* backend until one works or all fail. It may not be possible for all
* flavors, but where it's possible we should.
*/
#if defined(HAVE_LMDB)
static struct hdb_method default_dbmethod =
{ HDB_INTERFACE_VERSION, NULL, NULL, "", hdb_mdb_create };
#elif defined(HAVE_DB3)
static struct hdb_method default_dbmethod =
{ HDB_INTERFACE_VERSION, NULL, NULL, "", hdb_db3_create };
#elif defined(HAVE_DB1)
static struct hdb_method default_dbmethod =
{ HDB_INTERFACE_VERSION, NULL, NULL, "", hdb_db1_create };
#elif defined(HAVE_NDBM)
static struct hdb_method default_dbmethod =
{ HDB_INTERFACE_VERSION, NULL, NULL, "", hdb_ndbm_create };
#endif
/**
* Returns the Keys of `e' for `kvno', or NULL if not found. The Keys will
* remain valid provided that the entry is not mutated.
*
* @param context Context
* @param e The HDB entry
* @param kvno The kvno
*
* @return A pointer to the Keys for the requested kvno.
*/
const Keys *
hdb_kvno2keys(krb5_context context,
const hdb_entry *e,
krb5_kvno kvno)
{
HDB_Ext_KeySet *hist_keys;
HDB_extension *extp;
size_t i;
if (kvno == 0 || e->kvno == kvno)
return &e->keys;
extp = hdb_find_extension(e, choice_HDB_extension_data_hist_keys);
if (extp == NULL)
return 0;
hist_keys = &extp->data.u.hist_keys;
for (i = 0; i < hist_keys->len; i++) {
if (hist_keys->val[i].kvno == kvno)
return &hist_keys->val[i].keys;
}
return NULL;
}
/* Based on remove_HDB_Ext_KeySet(), generated by the ASN.1 compiler */
static int
dequeue_HDB_Ext_KeySet(HDB_Ext_KeySet *data, unsigned int element, hdb_keyset *ks)
{
if (element >= data->len) {
ks->kvno = 0;
ks->keys.len = 0;
ks->keys.val = 0;
ks->set_time = 0;
return ASN1_OVERRUN;
}
*ks = data->val[element];
data->len--;
/* Swap instead of memmove()... changes the order of elements */
if (element < data->len)
data->val[element] = data->val[data->len];
if (data->len == 0) {
free(data->val);
data->val = 0;
}
return 0;
}
/**
* Removes from `e' and optionally outputs the keyset for the requested `kvno'.
*
* @param context Context
* @param e The HDB entry
* @param kvno The key version number
* @param ks A pointer to a variable of type hdb_keyset (may be NULL)
*
* @return Zero on success, an error code otherwise.
*/
krb5_error_code
hdb_remove_keys(krb5_context context,
hdb_entry *e,
krb5_kvno kvno,
hdb_keyset *ks)
{
HDB_Ext_KeySet *hist_keys;
HDB_extension *extp;
size_t i;
if (kvno == 0 || e->kvno == kvno) {
if (ks) {
KerberosTime t;
(void) hdb_entry_get_pw_change_time(e, &t);
if (t) {
if ((ks->set_time = malloc(sizeof(*ks->set_time))) == NULL)
return krb5_enomem(context);
*ks->set_time = t;
}
ks->kvno = e->kvno;
ks->keys = e->keys;
e->keys.len = 0;
e->keys.val = NULL;
e->kvno = 0;
} else {
free_Keys(&e->keys);
}
return 0;
}
if (ks) {
ks->kvno = 0;
ks->keys.len = 0;
ks->keys.val = 0;
ks->set_time = 0;
}
extp = hdb_find_extension(e, choice_HDB_extension_data_hist_keys);
if (extp == NULL)
return 0;
hist_keys = &extp->data.u.hist_keys;
for (i = 0; i < hist_keys->len; i++) {
if (hist_keys->val[i].kvno != kvno)
continue;
if (ks)
return dequeue_HDB_Ext_KeySet(hist_keys, i, ks);
return remove_HDB_Ext_KeySet(hist_keys, i);
}
return HDB_ERR_NOENTRY;
}
/**
* Removes from `e' and outputs all the base keys for virtual principal and/or
* key derivation.
*
* @param context Context
* @param e The HDB entry
* @param ks A pointer to a variable of type HDB_Ext_KeySet
*
* @return Zero on success, an error code otherwise.
*/
krb5_error_code
hdb_remove_base_keys(krb5_context context,
hdb_entry *e,
HDB_Ext_KeySet *base_keys)
{
krb5_error_code ret;
const HDB_Ext_KeyRotation *ckr;
HDB_Ext_KeyRotation kr;
size_t i, k;
ret = hdb_entry_get_key_rotation(context, e, &ckr);
if (ret == 0) {
/*
* Changing the entry's extensions invalidates extensions obtained
* before the change.
*/
ret = copy_HDB_Ext_KeyRotation(ckr, &kr);
ckr = NULL;
}
base_keys->len = 0;
if (ret == 0 &&
(base_keys->val = calloc(kr.len, sizeof(base_keys->val[0]))) == NULL)
ret = krb5_enomem(context);
for (k = i = 0; ret == 0 && i < kr.len; i++) {
const KeyRotation *krp = &kr.val[i];
/*
* WARNING: O(N * M) where M is number of keysets and N is the number
* of base keysets.
*
* In practice N will never be > 3 because the ASN.1 module imposes
* that as a constraint, and M will generally be the same as N, so this
* will be O(1) after all.
*/
ret = hdb_remove_keys(context, e, krp->base_key_kvno,
&base_keys->val[k]);
if (ret == 0)
k++;
else if (ret == HDB_ERR_NOENTRY)
ret = 0;
}
if (ret == 0)
base_keys->len = k;
else
free_HDB_Ext_KeySet(base_keys);
free_HDB_Ext_KeyRotation(&kr);
return 0;
}
/**
* Removes from `e' and outputs all the base keys for virtual principal and/or
* key derivation.
*
* @param context Context
* @param e The HDB entry
* @param is_current_keyset Whether to make the keys the current keys for `e'
* @param ks A pointer to an hdb_keyset containing the keys to set
*
* @return Zero on success, an error code otherwise.
*/
krb5_error_code
hdb_install_keyset(krb5_context context,
hdb_entry *e,
int is_current_keyset,
const hdb_keyset *ks)
{
krb5_error_code ret = 0;
if (is_current_keyset) {
if (e->keys.len &&
(ret = hdb_add_current_keys_to_history(context, e)))
return ret;
free_Keys(&e->keys);
if (ret == 0)
ret = copy_Keys(&ks->keys, &e->keys);
e->kvno = ks->kvno;
if (ks->set_time)
return hdb_entry_set_pw_change_time(context, e, *ks->set_time);
return 0;
}
return hdb_add_history_keyset(context, e, ks);
}
krb5_error_code
hdb_next_enctype2key(krb5_context context,
const hdb_entry *e,
const Keys *keyset,
krb5_enctype enctype,
Key **key)
{
const Keys *keys = keyset ? keyset : &e->keys;
Key *k;
for (k = *key ? (*key) + 1 : keys->val; k < keys->val + keys->len; k++) {
if(k->key.keytype == enctype){
*key = k;
return 0;
}
}
krb5_set_error_message(context, KRB5_PROG_ETYPE_NOSUPP,
"No next enctype %d for hdb-entry",
(int)enctype);
return KRB5_PROG_ETYPE_NOSUPP; /* XXX */
}
krb5_error_code
hdb_enctype2key(krb5_context context,
hdb_entry *e,
const Keys *keyset,
krb5_enctype enctype,
Key **key)
{
*key = NULL;
return hdb_next_enctype2key(context, e, keyset, enctype, key);
}
void
hdb_free_key(Key *key)
{
memset(key->key.keyvalue.data,
0,
key->key.keyvalue.length);
free_Key(key);
free(key);
}
krb5_error_code
hdb_lock(int fd, int operation)
{
int i, code = 0;
for(i = 0; i < 3; i++){
code = flock(fd, (operation == HDB_RLOCK ? LOCK_SH : LOCK_EX) | LOCK_NB);
if(code == 0 || errno != EWOULDBLOCK)
break;
sleep(1);
}
if(code == 0)
return 0;
if(errno == EWOULDBLOCK)
return HDB_ERR_DB_INUSE;
return HDB_ERR_CANT_LOCK_DB;
}
krb5_error_code
hdb_unlock(int fd)
{
int code;
code = flock(fd, LOCK_UN);
if(code)
return 4711 /* XXX */;
return 0;
}
void
hdb_free_entry(krb5_context context, hdb_entry_ex *ent)
{
Key *k;
size_t i;
if (ent->free_entry)
(*ent->free_entry)(context, ent);
for(i = 0; i < ent->entry.keys.len; i++) {
k = &ent->entry.keys.val[i];
memset (k->key.keyvalue.data, 0, k->key.keyvalue.length);
}
free_hdb_entry(&ent->entry);
}
krb5_error_code
hdb_foreach(krb5_context context,
HDB *db,
unsigned flags,
hdb_foreach_func_t func,
void *data)
{
krb5_error_code ret;
hdb_entry_ex entry;
ret = db->hdb_firstkey(context, db, flags, &entry);
if (ret == 0)
krb5_clear_error_message(context);
while(ret == 0){
ret = (*func)(context, db, &entry, data);
hdb_free_entry(context, &entry);
if(ret == 0)
ret = db->hdb_nextkey(context, db, flags, &entry);
}
if(ret == HDB_ERR_NOENTRY)
ret = 0;
return ret;
}
krb5_error_code
hdb_check_db_format(krb5_context context, HDB *db)
{
krb5_data tag;
krb5_data version;
krb5_error_code ret, ret2;
unsigned ver;
int foo;
ret = db->hdb_lock(context, db, HDB_RLOCK);
if (ret)
return ret;
tag.data = (void *)(intptr_t)HDB_DB_FORMAT_ENTRY;
tag.length = strlen(tag.data);
ret = (*db->hdb__get)(context, db, tag, &version);
ret2 = db->hdb_unlock(context, db);
if(ret)
return ret;
if (ret2)
return ret2;
foo = sscanf(version.data, "%u", &ver);
krb5_data_free (&version);
if (foo != 1)
return HDB_ERR_BADVERSION;
if(ver != HDB_DB_FORMAT)
return HDB_ERR_BADVERSION;
return 0;
}
krb5_error_code
hdb_init_db(krb5_context context, HDB *db)
{
krb5_error_code ret, ret2;
krb5_data tag;
krb5_data version;
char ver[32];
ret = hdb_check_db_format(context, db);
if(ret != HDB_ERR_NOENTRY)
return ret;
ret = db->hdb_lock(context, db, HDB_WLOCK);
if (ret)
return ret;
tag.data = (void *)(intptr_t)HDB_DB_FORMAT_ENTRY;
tag.length = strlen(tag.data);
snprintf(ver, sizeof(ver), "%u", HDB_DB_FORMAT);
version.data = ver;
version.length = strlen(version.data) + 1; /* zero terminated */
ret = (*db->hdb__put)(context, db, 0, tag, version);
ret2 = db->hdb_unlock(context, db);
if (ret) {
if (ret2)
krb5_clear_error_message(context);
return ret;
}
return ret2;
}
/*
* find the relevant method for `filename', returning a pointer to the
* rest in `rest'.
* return NULL if there's no such method.
*/
static const struct hdb_method *
find_method (const char *filename, const char **rest)
{
const struct hdb_method *h;
for (h = methods; h->prefix != NULL; ++h) {
if (strncmp (filename, h->prefix, strlen(h->prefix)) == 0) {
*rest = filename + strlen(h->prefix);
return h;
}
}
#if defined(HAVE_DB1) || defined(HAVE_DB3) || defined(HAVE_LMDB) || defined(HAVE_NDBM)
if (strncmp(filename, "/", sizeof("/") - 1) == 0
|| strncmp(filename, "./", sizeof("./") - 1) == 0
|| strncmp(filename, "../", sizeof("../") - 1) == 0
#ifdef WIN32
|| strncmp(filename, "\\\\", sizeof("\\\\") - 1)
|| (isalpha(filename[0]) && filename[1] == ':')
#endif
)
{
*rest = filename;
return &default_dbmethod;
}
#endif
return NULL;
}
struct cb_s {
const char *residual;
const char *filename;
const struct hdb_method *h;
};
static krb5_error_code KRB5_LIB_CALL
callback(krb5_context context, const void *plug, void *plugctx, void *userctx)
{
const struct hdb_method *h = (const struct hdb_method *)plug;
struct cb_s *cb_ctx = (struct cb_s *)userctx;
if (strncmp(cb_ctx->filename, h->prefix, strlen(h->prefix)) == 0) {
cb_ctx->residual = cb_ctx->filename + strlen(h->prefix) + 1;
cb_ctx->h = h;
return 0;
}
return KRB5_PLUGIN_NO_HANDLE;
}
static char *
make_sym(const char *prefix)
{
char *s, *sym;
errno = 0;
if (prefix == NULL || prefix[0] == '\0')
return NULL;
if ((s = strdup(prefix)) == NULL)
return NULL;
if (strchr(s, ':') != NULL)
*strchr(s, ':') = '\0';
if (asprintf(&sym, "hdb_%s_interface", s) == -1)
sym = NULL;
free(s);
return sym;
}
static const char *hdb_plugin_deps[] = { "hdb", "krb5", NULL };
krb5_error_code
hdb_list_builtin(krb5_context context, char **list)
{
const struct hdb_method *h;
size_t len = 0;
char *buf = NULL;
for (h = methods; h->prefix != NULL; ++h) {
if (h->prefix[0] == '\0')
continue;
len += strlen(h->prefix) + 2;
}
len += 1;
buf = malloc(len);
if (buf == NULL) {
return krb5_enomem(context);
}
buf[0] = '\0';
for (h = methods; h->prefix != NULL; ++h) {
if (h->create == NULL) {
struct cb_s cb_ctx;
char *f;
struct heim_plugin_data hdb_plugin_data;
hdb_plugin_data.module = "krb5";
hdb_plugin_data.min_version = HDB_INTERFACE_VERSION;
hdb_plugin_data.deps = hdb_plugin_deps;
hdb_plugin_data.get_instance = hdb_get_instance;
/* Try loading the plugin */
if (asprintf(&f, "%sfoo", h->prefix) == -1)
f = NULL;
if ((hdb_plugin_data.name = make_sym(h->prefix)) == NULL) {
free(buf);
free(f);
return krb5_enomem(context);
}
cb_ctx.filename = f;
cb_ctx.residual = NULL;
cb_ctx.h = NULL;
(void)_krb5_plugin_run_f(context, &hdb_plugin_data, 0,
&cb_ctx, callback);
free(f);
free(rk_UNCONST(hdb_plugin_data.name));
if (cb_ctx.h == NULL || cb_ctx.h->create == NULL)
continue;
}
if (h != methods)
strlcat(buf, ", ", len);
strlcat(buf, h->prefix, len);
}
*list = buf;
return 0;
}
krb5_error_code
_hdb_keytab2hdb_entry(krb5_context context,
const krb5_keytab_entry *ktentry,
hdb_entry_ex *entry)
{
entry->entry.kvno = ktentry->vno;
entry->entry.created_by.time = ktentry->timestamp;
entry->entry.keys.val = calloc(1, sizeof(entry->entry.keys.val[0]));
if (entry->entry.keys.val == NULL)
return ENOMEM;
entry->entry.keys.len = 1;
entry->entry.keys.val[0].mkvno = NULL;
entry->entry.keys.val[0].salt = NULL;
return krb5_copy_keyblock_contents(context,
&ktentry->keyblock,
&entry->entry.keys.val[0].key);
}
/**
* Create a handle for a Kerberos database
*
* Create a handle for a Kerberos database backend specified by a
* filename. Doesn't create a file if its doesn't exists, you have to
* use O_CREAT to tell the backend to create the file.
*/
krb5_error_code
hdb_create(krb5_context context, HDB **db, const char *filename)
{
krb5_error_code ret;
struct cb_s cb_ctx;
*db = NULL;
if (filename == NULL)
filename = HDB_DEFAULT_DB;
cb_ctx.h = find_method (filename, &cb_ctx.residual);
cb_ctx.filename = filename;
if (cb_ctx.h == NULL || cb_ctx.h->create == NULL) {
struct heim_plugin_data hdb_plugin_data;
hdb_plugin_data.module = "krb5";
hdb_plugin_data.min_version = HDB_INTERFACE_VERSION;
hdb_plugin_data.deps = hdb_plugin_deps;
hdb_plugin_data.get_instance = hdb_get_instance;
if ((hdb_plugin_data.name = make_sym(filename)) == NULL)
return krb5_enomem(context);
(void)_krb5_plugin_run_f(context, &hdb_plugin_data,
0, &cb_ctx, callback);
free(rk_UNCONST(hdb_plugin_data.name));
}
/* XXX krb5_errx()?! */
if (cb_ctx.h == NULL)
krb5_errx(context, 1, "No database support for %s", cb_ctx.filename);
ret = (*cb_ctx.h->create)(context, db, cb_ctx.residual);
if (ret == 0 && *db) {
(*db)->enable_virtual_hostbased_princs =
krb5_config_get_bool_default(context, NULL, FALSE, "hdb",
"enable_virtual_hostbased_princs",
NULL);
(*db)->virtual_hostbased_princ_ndots =
krb5_config_get_int_default(context, NULL, 1, "hdb",
"virtual_hostbased_princ_mindots",
NULL);
(*db)->virtual_hostbased_princ_maxdots =
krb5_config_get_int_default(context, NULL, 0, "hdb",
"virtual_hostbased_princ_maxdots",
NULL);
(*db)->new_service_key_delay =
krb5_config_get_time_default(context, NULL, 0, "hdb",
"new_service_key_delay", NULL);
/*
* XXX Needs freeing in the HDB backends because we don't have a
* first-class hdb_close() :(
*/
(*db)->virtual_hostbased_princ_svcs =
krb5_config_get_strings(context, NULL, "hdb",
"virtual_hostbased_princ_svcs", NULL);
/* Check for ENOMEM */
if ((*db)->virtual_hostbased_princ_svcs == NULL
&& krb5_config_get_string(context, NULL, "hdb",
"virtual_hostbased_princ_svcs", NULL)) {
(*db)->hdb_destroy(context, *db);
*db = NULL;
ret = krb5_enomem(context);
}
}
return ret;
}
uintptr_t KRB5_CALLCONV
hdb_get_instance(const char *libname)
{
static const char *instance = "libhdb";
if (strcmp(libname, "hdb") == 0)
return (uintptr_t)instance;
else if (strcmp(libname, "krb5") == 0)
return krb5_get_instance(libname);
return 0;
}
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