Files
heimdal/lib/hdb/db.c
Roland C. Dowdeswell 1f63d6e4dc Fix locking issues in DB1 HDB backend.
Multiple concurrent writers would cause the HDB to become corrupted
as the locking was not sufficient to prevent these sorts of issues
from occurring.  We have changed the locking to obtain the appropriate
kind of lock on database open and to hold that lock until the
database closes.  We need to do this as Berkeley DB 1.85 will cache
information from the database in memory and if if this information
is updated without our knowledge then our later writes will corrupt
the database.  We speculate that there would be issues with a single
writer and reader but did not reproduce them.
2012-05-18 12:39:08 +01:00

361 lines
8.9 KiB
C

/*
* Copyright (c) 1997 - 2001 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 "hdb_locl.h"
#if HAVE_DB1
#if defined(HAVE_DB_185_H)
#include <db_185.h>
#elif defined(HAVE_DB_H)
#include <db.h>
#endif
typedef struct {
HDB hdb; /* generic members */
int lock_fd; /* DB-specific */
} DB1_HDB;
static krb5_error_code
DB_close(krb5_context context, HDB *db)
{
DB1_HDB *db1 = (DB1_HDB *)db;
DB *d = (DB*)db->hdb_db;
heim_assert(d != 0, "Closing already closed HDB");
(*d->close)(d);
db->hdb_db = 0;
if (db1->lock_fd >= 0) {
close(db1->lock_fd);
db1->lock_fd = -1;
}
return 0;
}
static krb5_error_code
DB_destroy(krb5_context context, HDB *db)
{
krb5_error_code ret;
ret = hdb_clear_master_key (context, db);
free(db->hdb_name);
free(db);
return ret;
}
static krb5_error_code
DB_lock(krb5_context context, HDB *db, int operation)
{
return 0;
}
static krb5_error_code
DB_unlock(krb5_context context, HDB *db)
{
return 0;
}
static krb5_error_code
DB_seq(krb5_context context, HDB *db,
unsigned flags, hdb_entry_ex *entry, int flag)
{
DB *d = (DB*)db->hdb_db;
DBT key, value;
krb5_data key_data, data;
int code;
code = (*d->seq)(d, &key, &value, flag);
if(code == -1) {
code = errno;
krb5_set_error_message(context, code, "Database %s seq error: %s",
db->hdb_name, strerror(code));
return code;
}
if(code == 1) {
krb5_clear_error_message(context);
return HDB_ERR_NOENTRY;
}
key_data.data = key.data;
key_data.length = key.size;
data.data = value.data;
data.length = value.size;
memset(entry, 0, sizeof(*entry));
if (hdb_value2entry(context, &data, &entry->entry))
return DB_seq(context, db, flags, entry, R_NEXT);
if (db->hdb_master_key_set && (flags & HDB_F_DECRYPT)) {
code = hdb_unseal_keys (context, db, &entry->entry);
if (code)
hdb_free_entry (context, entry);
}
if (code == 0 && entry->entry.principal == NULL) {
entry->entry.principal = malloc(sizeof(*entry->entry.principal));
if (entry->entry.principal == NULL) {
code = ENOMEM;
krb5_set_error_message(context, code, "malloc: out of memory");
hdb_free_entry (context, entry);
} else {
hdb_key2principal(context, &key_data, entry->entry.principal);
}
}
return code;
}
static krb5_error_code
DB_firstkey(krb5_context context, HDB *db, unsigned flags, hdb_entry_ex *entry)
{
return DB_seq(context, db, flags, entry, R_FIRST);
}
static krb5_error_code
DB_nextkey(krb5_context context, HDB *db, unsigned flags, hdb_entry_ex *entry)
{
return DB_seq(context, db, flags, entry, R_NEXT);
}
static krb5_error_code
DB_rename(krb5_context context, HDB *db, const char *new_name)
{
int ret;
char *old, *new;
asprintf(&old, "%s.db", db->hdb_name);
asprintf(&new, "%s.db", new_name);
ret = rename(old, new);
free(old);
free(new);
if(ret)
return errno;
free(db->hdb_name);
db->hdb_name = strdup(new_name);
return 0;
}
static krb5_error_code
DB__get(krb5_context context, HDB *db, krb5_data key, krb5_data *reply)
{
DB *d = (DB*)db->hdb_db;
DBT k, v;
int code;
k.data = key.data;
k.size = key.length;
code = (*d->get)(d, &k, &v, 0);
if(code < 0) {
code = errno;
krb5_set_error_message(context, code, "Database %s get error: %s",
db->hdb_name, strerror(code));
return code;
}
if(code == 1) {
krb5_clear_error_message(context);
return HDB_ERR_NOENTRY;
}
krb5_data_copy(reply, v.data, v.size);
return 0;
}
static krb5_error_code
DB__put(krb5_context context, HDB *db, int replace,
krb5_data key, krb5_data value)
{
DB *d = (DB*)db->hdb_db;
DBT k, v;
int code;
k.data = key.data;
k.size = key.length;
v.data = value.data;
v.size = value.length;
code = (*d->put)(d, &k, &v, replace ? 0 : R_NOOVERWRITE);
if(code < 0) {
code = errno;
krb5_set_error_message(context, code, "Database %s put error: %s",
db->hdb_name, strerror(code));
return code;
}
if(code == 1) {
krb5_clear_error_message(context);
return HDB_ERR_EXISTS;
}
return 0;
}
static krb5_error_code
DB__del(krb5_context context, HDB *db, krb5_data key)
{
DB *d = (DB*)db->hdb_db;
DBT k;
krb5_error_code code;
k.data = key.data;
k.size = key.length;
code = (*d->del)(d, &k, 0);
if(code == 1) {
code = errno;
krb5_set_error_message(context, code, "Database %s put error: %s",
db->hdb_name, strerror(code));
return code;
}
if(code < 0)
return errno;
return 0;
}
static DB *
_open_db(char *fn, int flags, int mode, int *fd)
{
#ifndef O_EXLOCK
int op;
int ret;
*fd = open(fn, flags, mode);
if (*fd == -1)
return NULL;
if ((flags & O_ACCMODE) == O_RDONLY)
op = LOCK_SH;
else
op = LOCK_EX;
ret = flock(*fd, op);
if (ret == -1) {
int saved_errno;
saved_errno = errno;
close(*fd);
errno = saved_errno;
return NULL;
}
#else
if ((flags & O_ACCMODE) == O_RDONLY)
flags |= O_SHLOCK;
else
flags |= O_EXLOCK;
#endif
return dbopen(fn, flags, mode, DB_BTREE, NULL);
}
static krb5_error_code
DB_open(krb5_context context, HDB *db, int flags, mode_t mode)
{
DB1_HDB *db1 = (DB1_HDB *)db;
char *fn;
krb5_error_code ret;
asprintf(&fn, "%s.db", db->hdb_name);
if (fn == NULL) {
krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
return ENOMEM;
}
db->hdb_db = _open_db(fn, flags, mode, &db1->lock_fd);
free(fn);
/* try to open without .db extension */
if(db->hdb_db == NULL && errno == ENOENT)
db->hdb_db = _open_db(db->hdb_name, flags, mode, &db1->lock_fd);
if(db->hdb_db == NULL) {
krb5_set_error_message(context, errno, "dbopen (%s): %s",
db->hdb_name, strerror(errno));
return errno;
}
if((flags & O_ACCMODE) == O_RDONLY)
ret = hdb_check_db_format(context, db);
else
ret = hdb_init_db(context, db);
if(ret == HDB_ERR_NOENTRY) {
krb5_clear_error_message(context);
return 0;
}
if (ret) {
DB_close(context, db);
krb5_set_error_message(context, ret, "hdb_open: failed %s database %s",
(flags & O_ACCMODE) == O_RDONLY ?
"checking format of" : "initialize",
db->hdb_name);
}
return ret;
}
krb5_error_code
hdb_db_create(krb5_context context, HDB **db,
const char *filename)
{
DB1_HDB **db1 = (DB1_HDB **)db;
*db = calloc(1, sizeof(**db1)); /* Allocate space for the larger db3 */
if (*db == NULL) {
krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
return ENOMEM;
}
(*db)->hdb_db = NULL;
(*db)->hdb_name = strdup(filename);
if ((*db)->hdb_name == NULL) {
free(*db);
*db = NULL;
krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
return ENOMEM;
}
(*db)->hdb_master_key_set = 0;
(*db)->hdb_openp = 0;
(*db)->hdb_capability_flags = HDB_CAP_F_HANDLE_ENTERPRISE_PRINCIPAL;
(*db)->hdb_open = DB_open;
(*db)->hdb_close = DB_close;
(*db)->hdb_fetch_kvno = _hdb_fetch_kvno;
(*db)->hdb_store = _hdb_store;
(*db)->hdb_remove = _hdb_remove;
(*db)->hdb_firstkey = DB_firstkey;
(*db)->hdb_nextkey= DB_nextkey;
(*db)->hdb_lock = DB_lock;
(*db)->hdb_unlock = DB_unlock;
(*db)->hdb_rename = DB_rename;
(*db)->hdb__get = DB__get;
(*db)->hdb__put = DB__put;
(*db)->hdb__del = DB__del;
(*db)->hdb_destroy = DB_destroy;
(*db1)->lock_fd = -1;
return 0;
}
#endif /* HAVE_DB1 */