linux/fs/ksmbd/server.c
Steve French e44fd5081c ksmbd: log that server is experimental at module load
While we are working through detailed security reviews
of ksmbd server code we should remind users that it is an
experimental module by adding a warning when the module
loads.  Currently the module shows as experimental
in Kconfig and is disabled by default, but we don't want
to confuse users.

Although ksmbd passes a wide variety of the
important functional tests (since initial focus had
been largely on functional testing such as smbtorture,
xfstests etc.), and ksmbd has added key security
features (e.g. GCM256 encryption, Kerberos support),
there are ongoing detailed reviews of the code base
for path processing and network buffer decoding, and
this patch reminds users that the module should be
considered "experimental."

Reviewed-by: Namjae Jeon <linkinjeon@kernel.org>
Reviewed-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
2021-09-21 12:35:20 -05:00

637 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2016 Namjae Jeon <linkinjeon@kernel.org>
* Copyright (C) 2018 Samsung Electronics Co., Ltd.
*/
#include "glob.h"
#include "oplock.h"
#include "misc.h"
#include <linux/sched/signal.h>
#include <linux/workqueue.h>
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include "server.h"
#include "smb_common.h"
#include "smbstatus.h"
#include "connection.h"
#include "transport_ipc.h"
#include "mgmt/user_session.h"
#include "crypto_ctx.h"
#include "auth.h"
int ksmbd_debug_types;
struct ksmbd_server_config server_conf;
enum SERVER_CTRL_TYPE {
SERVER_CTRL_TYPE_INIT,
SERVER_CTRL_TYPE_RESET,
};
struct server_ctrl_struct {
int type;
struct work_struct ctrl_work;
};
static DEFINE_MUTEX(ctrl_lock);
static int ___server_conf_set(int idx, char *val)
{
if (idx >= ARRAY_SIZE(server_conf.conf))
return -EINVAL;
if (!val || val[0] == 0x00)
return -EINVAL;
kfree(server_conf.conf[idx]);
server_conf.conf[idx] = kstrdup(val, GFP_KERNEL);
if (!server_conf.conf[idx])
return -ENOMEM;
return 0;
}
int ksmbd_set_netbios_name(char *v)
{
return ___server_conf_set(SERVER_CONF_NETBIOS_NAME, v);
}
int ksmbd_set_server_string(char *v)
{
return ___server_conf_set(SERVER_CONF_SERVER_STRING, v);
}
int ksmbd_set_work_group(char *v)
{
return ___server_conf_set(SERVER_CONF_WORK_GROUP, v);
}
char *ksmbd_netbios_name(void)
{
return server_conf.conf[SERVER_CONF_NETBIOS_NAME];
}
char *ksmbd_server_string(void)
{
return server_conf.conf[SERVER_CONF_SERVER_STRING];
}
char *ksmbd_work_group(void)
{
return server_conf.conf[SERVER_CONF_WORK_GROUP];
}
/**
* check_conn_state() - check state of server thread connection
* @work: smb work containing server thread information
*
* Return: 0 on valid connection, otherwise 1 to reconnect
*/
static inline int check_conn_state(struct ksmbd_work *work)
{
struct smb_hdr *rsp_hdr;
if (ksmbd_conn_exiting(work) || ksmbd_conn_need_reconnect(work)) {
rsp_hdr = work->response_buf;
rsp_hdr->Status.CifsError = STATUS_CONNECTION_DISCONNECTED;
return 1;
}
return 0;
}
#define SERVER_HANDLER_CONTINUE 0
#define SERVER_HANDLER_ABORT 1
static int __process_request(struct ksmbd_work *work, struct ksmbd_conn *conn,
u16 *cmd)
{
struct smb_version_cmds *cmds;
u16 command;
int ret;
if (check_conn_state(work))
return SERVER_HANDLER_CONTINUE;
if (ksmbd_verify_smb_message(work))
return SERVER_HANDLER_ABORT;
command = conn->ops->get_cmd_val(work);
*cmd = command;
andx_again:
if (command >= conn->max_cmds) {
conn->ops->set_rsp_status(work, STATUS_INVALID_PARAMETER);
return SERVER_HANDLER_CONTINUE;
}
cmds = &conn->cmds[command];
if (!cmds->proc) {
ksmbd_debug(SMB, "*** not implemented yet cmd = %x\n", command);
conn->ops->set_rsp_status(work, STATUS_NOT_IMPLEMENTED);
return SERVER_HANDLER_CONTINUE;
}
if (work->sess && conn->ops->is_sign_req(work, command)) {
ret = conn->ops->check_sign_req(work);
if (!ret) {
conn->ops->set_rsp_status(work, STATUS_ACCESS_DENIED);
return SERVER_HANDLER_CONTINUE;
}
}
ret = cmds->proc(work);
if (ret < 0)
ksmbd_debug(CONN, "Failed to process %u [%d]\n", command, ret);
/* AndX commands - chained request can return positive values */
else if (ret > 0) {
command = ret;
*cmd = command;
goto andx_again;
}
if (work->send_no_response)
return SERVER_HANDLER_ABORT;
return SERVER_HANDLER_CONTINUE;
}
static void __handle_ksmbd_work(struct ksmbd_work *work,
struct ksmbd_conn *conn)
{
u16 command = 0;
int rc;
if (conn->ops->allocate_rsp_buf(work))
return;
if (conn->ops->is_transform_hdr &&
conn->ops->is_transform_hdr(work->request_buf)) {
rc = conn->ops->decrypt_req(work);
if (rc < 0) {
conn->ops->set_rsp_status(work, STATUS_DATA_ERROR);
goto send;
}
work->encrypted = true;
}
rc = conn->ops->init_rsp_hdr(work);
if (rc) {
/* either uid or tid is not correct */
conn->ops->set_rsp_status(work, STATUS_INVALID_HANDLE);
goto send;
}
if (conn->ops->check_user_session) {
rc = conn->ops->check_user_session(work);
if (rc < 0) {
command = conn->ops->get_cmd_val(work);
conn->ops->set_rsp_status(work,
STATUS_USER_SESSION_DELETED);
goto send;
} else if (rc > 0) {
rc = conn->ops->get_ksmbd_tcon(work);
if (rc < 0) {
conn->ops->set_rsp_status(work,
STATUS_NETWORK_NAME_DELETED);
goto send;
}
}
}
do {
rc = __process_request(work, conn, &command);
if (rc == SERVER_HANDLER_ABORT)
break;
/*
* Call smb2_set_rsp_credits() function to set number of credits
* granted in hdr of smb2 response.
*/
if (conn->ops->set_rsp_credits) {
spin_lock(&conn->credits_lock);
rc = conn->ops->set_rsp_credits(work);
spin_unlock(&conn->credits_lock);
if (rc < 0) {
conn->ops->set_rsp_status(work,
STATUS_INVALID_PARAMETER);
goto send;
}
}
if (work->sess &&
(work->sess->sign || smb3_11_final_sess_setup_resp(work) ||
conn->ops->is_sign_req(work, command)))
conn->ops->set_sign_rsp(work);
} while (is_chained_smb2_message(work));
if (work->send_no_response)
return;
send:
smb3_preauth_hash_rsp(work);
if (work->sess && work->sess->enc && work->encrypted &&
conn->ops->encrypt_resp) {
rc = conn->ops->encrypt_resp(work);
if (rc < 0) {
conn->ops->set_rsp_status(work, STATUS_DATA_ERROR);
goto send;
}
}
ksmbd_conn_write(work);
}
/**
* handle_ksmbd_work() - process pending smb work requests
* @wk: smb work containing request command buffer
*
* called by kworker threads to processing remaining smb work requests
*/
static void handle_ksmbd_work(struct work_struct *wk)
{
struct ksmbd_work *work = container_of(wk, struct ksmbd_work, work);
struct ksmbd_conn *conn = work->conn;
atomic64_inc(&conn->stats.request_served);
__handle_ksmbd_work(work, conn);
ksmbd_conn_try_dequeue_request(work);
ksmbd_free_work_struct(work);
atomic_dec(&conn->r_count);
}
/**
* queue_ksmbd_work() - queue a smb request to worker thread queue
* for proccessing smb command and sending response
* @conn: connection instance
*
* read remaining data from socket create and submit work.
*/
static int queue_ksmbd_work(struct ksmbd_conn *conn)
{
struct ksmbd_work *work;
work = ksmbd_alloc_work_struct();
if (!work) {
pr_err("allocation for work failed\n");
return -ENOMEM;
}
work->conn = conn;
work->request_buf = conn->request_buf;
conn->request_buf = NULL;
if (ksmbd_init_smb_server(work)) {
ksmbd_free_work_struct(work);
return -EINVAL;
}
ksmbd_conn_enqueue_request(work);
atomic_inc(&conn->r_count);
/* update activity on connection */
conn->last_active = jiffies;
INIT_WORK(&work->work, handle_ksmbd_work);
ksmbd_queue_work(work);
return 0;
}
static int ksmbd_server_process_request(struct ksmbd_conn *conn)
{
return queue_ksmbd_work(conn);
}
static int ksmbd_server_terminate_conn(struct ksmbd_conn *conn)
{
ksmbd_sessions_deregister(conn);
destroy_lease_table(conn);
return 0;
}
static void ksmbd_server_tcp_callbacks_init(void)
{
struct ksmbd_conn_ops ops;
ops.process_fn = ksmbd_server_process_request;
ops.terminate_fn = ksmbd_server_terminate_conn;
ksmbd_conn_init_server_callbacks(&ops);
}
static void server_conf_free(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(server_conf.conf); i++) {
kfree(server_conf.conf[i]);
server_conf.conf[i] = NULL;
}
}
static int server_conf_init(void)
{
WRITE_ONCE(server_conf.state, SERVER_STATE_STARTING_UP);
server_conf.enforced_signing = 0;
server_conf.min_protocol = ksmbd_min_protocol();
server_conf.max_protocol = ksmbd_max_protocol();
server_conf.auth_mechs = KSMBD_AUTH_NTLMSSP;
#ifdef CONFIG_SMB_SERVER_KERBEROS5
server_conf.auth_mechs |= KSMBD_AUTH_KRB5 |
KSMBD_AUTH_MSKRB5;
#endif
return 0;
}
static void server_ctrl_handle_init(struct server_ctrl_struct *ctrl)
{
int ret;
ret = ksmbd_conn_transport_init();
if (ret) {
server_queue_ctrl_reset_work();
return;
}
WRITE_ONCE(server_conf.state, SERVER_STATE_RUNNING);
}
static void server_ctrl_handle_reset(struct server_ctrl_struct *ctrl)
{
ksmbd_ipc_soft_reset();
ksmbd_conn_transport_destroy();
server_conf_free();
server_conf_init();
WRITE_ONCE(server_conf.state, SERVER_STATE_STARTING_UP);
}
static void server_ctrl_handle_work(struct work_struct *work)
{
struct server_ctrl_struct *ctrl;
ctrl = container_of(work, struct server_ctrl_struct, ctrl_work);
mutex_lock(&ctrl_lock);
switch (ctrl->type) {
case SERVER_CTRL_TYPE_INIT:
server_ctrl_handle_init(ctrl);
break;
case SERVER_CTRL_TYPE_RESET:
server_ctrl_handle_reset(ctrl);
break;
default:
pr_err("Unknown server work type: %d\n", ctrl->type);
}
mutex_unlock(&ctrl_lock);
kfree(ctrl);
module_put(THIS_MODULE);
}
static int __queue_ctrl_work(int type)
{
struct server_ctrl_struct *ctrl;
ctrl = kmalloc(sizeof(struct server_ctrl_struct), GFP_KERNEL);
if (!ctrl)
return -ENOMEM;
__module_get(THIS_MODULE);
ctrl->type = type;
INIT_WORK(&ctrl->ctrl_work, server_ctrl_handle_work);
queue_work(system_long_wq, &ctrl->ctrl_work);
return 0;
}
int server_queue_ctrl_init_work(void)
{
return __queue_ctrl_work(SERVER_CTRL_TYPE_INIT);
}
int server_queue_ctrl_reset_work(void)
{
return __queue_ctrl_work(SERVER_CTRL_TYPE_RESET);
}
static ssize_t stats_show(struct class *class, struct class_attribute *attr,
char *buf)
{
/*
* Inc this each time you change stats output format,
* so user space will know what to do.
*/
static int stats_version = 2;
static const char * const state[] = {
"startup",
"running",
"reset",
"shutdown"
};
ssize_t sz = scnprintf(buf, PAGE_SIZE, "%d %s %d %lu\n", stats_version,
state[server_conf.state], server_conf.tcp_port,
server_conf.ipc_last_active / HZ);
return sz;
}
static ssize_t kill_server_store(struct class *class,
struct class_attribute *attr, const char *buf,
size_t len)
{
if (!sysfs_streq(buf, "hard"))
return len;
pr_info("kill command received\n");
mutex_lock(&ctrl_lock);
WRITE_ONCE(server_conf.state, SERVER_STATE_RESETTING);
__module_get(THIS_MODULE);
server_ctrl_handle_reset(NULL);
module_put(THIS_MODULE);
mutex_unlock(&ctrl_lock);
return len;
}
static const char * const debug_type_strings[] = {"smb", "auth", "vfs",
"oplock", "ipc", "conn",
"rdma"};
static ssize_t debug_show(struct class *class, struct class_attribute *attr,
char *buf)
{
ssize_t sz = 0;
int i, pos = 0;
for (i = 0; i < ARRAY_SIZE(debug_type_strings); i++) {
if ((ksmbd_debug_types >> i) & 1) {
pos = scnprintf(buf + sz,
PAGE_SIZE - sz,
"[%s] ",
debug_type_strings[i]);
} else {
pos = scnprintf(buf + sz,
PAGE_SIZE - sz,
"%s ",
debug_type_strings[i]);
}
sz += pos;
}
sz += scnprintf(buf + sz, PAGE_SIZE - sz, "\n");
return sz;
}
static ssize_t debug_store(struct class *class, struct class_attribute *attr,
const char *buf, size_t len)
{
int i;
for (i = 0; i < ARRAY_SIZE(debug_type_strings); i++) {
if (sysfs_streq(buf, "all")) {
if (ksmbd_debug_types == KSMBD_DEBUG_ALL)
ksmbd_debug_types = 0;
else
ksmbd_debug_types = KSMBD_DEBUG_ALL;
break;
}
if (sysfs_streq(buf, debug_type_strings[i])) {
if (ksmbd_debug_types & (1 << i))
ksmbd_debug_types &= ~(1 << i);
else
ksmbd_debug_types |= (1 << i);
break;
}
}
return len;
}
static CLASS_ATTR_RO(stats);
static CLASS_ATTR_WO(kill_server);
static CLASS_ATTR_RW(debug);
static struct attribute *ksmbd_control_class_attrs[] = {
&class_attr_stats.attr,
&class_attr_kill_server.attr,
&class_attr_debug.attr,
NULL,
};
ATTRIBUTE_GROUPS(ksmbd_control_class);
static struct class ksmbd_control_class = {
.name = "ksmbd-control",
.owner = THIS_MODULE,
.class_groups = ksmbd_control_class_groups,
};
static int ksmbd_server_shutdown(void)
{
WRITE_ONCE(server_conf.state, SERVER_STATE_SHUTTING_DOWN);
class_unregister(&ksmbd_control_class);
ksmbd_workqueue_destroy();
ksmbd_ipc_release();
ksmbd_conn_transport_destroy();
ksmbd_crypto_destroy();
ksmbd_free_global_file_table();
destroy_lease_table(NULL);
ksmbd_work_pool_destroy();
ksmbd_exit_file_cache();
server_conf_free();
return 0;
}
static int __init ksmbd_server_init(void)
{
int ret;
ret = class_register(&ksmbd_control_class);
if (ret) {
pr_err("Unable to register ksmbd-control class\n");
return ret;
}
ksmbd_server_tcp_callbacks_init();
ret = server_conf_init();
if (ret)
goto err_unregister;
ret = ksmbd_work_pool_init();
if (ret)
goto err_unregister;
ret = ksmbd_init_file_cache();
if (ret)
goto err_destroy_work_pools;
ret = ksmbd_ipc_init();
if (ret)
goto err_exit_file_cache;
ret = ksmbd_init_global_file_table();
if (ret)
goto err_ipc_release;
ret = ksmbd_inode_hash_init();
if (ret)
goto err_destroy_file_table;
ret = ksmbd_crypto_create();
if (ret)
goto err_release_inode_hash;
ret = ksmbd_workqueue_init();
if (ret)
goto err_crypto_destroy;
pr_warn_once("The ksmbd server is experimental, use at your own risk.\n");
return 0;
err_crypto_destroy:
ksmbd_crypto_destroy();
err_release_inode_hash:
ksmbd_release_inode_hash();
err_destroy_file_table:
ksmbd_free_global_file_table();
err_ipc_release:
ksmbd_ipc_release();
err_exit_file_cache:
ksmbd_exit_file_cache();
err_destroy_work_pools:
ksmbd_work_pool_destroy();
err_unregister:
class_unregister(&ksmbd_control_class);
return ret;
}
/**
* ksmbd_server_exit() - shutdown forker thread and free memory at module exit
*/
static void __exit ksmbd_server_exit(void)
{
ksmbd_server_shutdown();
ksmbd_release_inode_hash();
}
MODULE_AUTHOR("Namjae Jeon <linkinjeon@kernel.org>");
MODULE_VERSION(KSMBD_VERSION);
MODULE_DESCRIPTION("Linux kernel CIFS/SMB SERVER");
MODULE_LICENSE("GPL");
MODULE_SOFTDEP("pre: ecb");
MODULE_SOFTDEP("pre: hmac");
MODULE_SOFTDEP("pre: md4");
MODULE_SOFTDEP("pre: md5");
MODULE_SOFTDEP("pre: nls");
MODULE_SOFTDEP("pre: aes");
MODULE_SOFTDEP("pre: cmac");
MODULE_SOFTDEP("pre: sha256");
MODULE_SOFTDEP("pre: sha512");
MODULE_SOFTDEP("pre: aead2");
MODULE_SOFTDEP("pre: ccm");
MODULE_SOFTDEP("pre: gcm");
module_init(ksmbd_server_init)
module_exit(ksmbd_server_exit)