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samba-mirror/source3/smbd/smb2_tcon.c
Ralph Wuerthner 5bba8c393d s3:smb2_tcon: Add check to prevent non-DFS clients from connecting to an msdfs proxy.
Signed-off-by: Ralph Wuerthner <ralph.wuerthner@de.ibm.com>
Reviewed-by: David Disseldorp <ddiss@samba.org>
Reviewed-by: Jeremy Allison <jra@samba.org>

Autobuild-User(master): Jeremy Allison <jra@samba.org>
Autobuild-Date(master): Sat Apr  7 05:05:22 CEST 2018 on sn-devel-144
2018-04-07 05:05:22 +02:00

667 lines
18 KiB
C

/*
Unix SMB/CIFS implementation.
Core SMB2 server
Copyright (C) Stefan Metzmacher 2009
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "smbd/smbd.h"
#include "smbd/globals.h"
#include "../libcli/smb/smb_common.h"
#include "../libcli/security/security.h"
#include "auth.h"
#include "lib/param/loadparm.h"
#include "../lib/util/tevent_ntstatus.h"
#undef DBGC_CLASS
#define DBGC_CLASS DBGC_SMB2
static struct tevent_req *smbd_smb2_tree_connect_send(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
struct smbd_smb2_request *smb2req,
const char *in_path);
static NTSTATUS smbd_smb2_tree_connect_recv(struct tevent_req *req,
uint8_t *out_share_type,
uint32_t *out_share_flags,
uint32_t *out_capabilities,
uint32_t *out_maximal_access,
uint32_t *out_tree_id,
bool *disconnect);
static void smbd_smb2_request_tcon_done(struct tevent_req *subreq);
NTSTATUS smbd_smb2_request_process_tcon(struct smbd_smb2_request *req)
{
const uint8_t *inbody;
uint16_t in_path_offset;
uint16_t in_path_length;
DATA_BLOB in_path_buffer;
char *in_path_string;
size_t in_path_string_size;
NTSTATUS status;
bool ok;
struct tevent_req *subreq;
status = smbd_smb2_request_verify_sizes(req, 0x09);
if (!NT_STATUS_IS_OK(status)) {
return smbd_smb2_request_error(req, status);
}
inbody = SMBD_SMB2_IN_BODY_PTR(req);
in_path_offset = SVAL(inbody, 0x04);
in_path_length = SVAL(inbody, 0x06);
if (in_path_offset != (SMB2_HDR_BODY + SMBD_SMB2_IN_BODY_LEN(req))) {
return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
}
if (in_path_length > SMBD_SMB2_IN_DYN_LEN(req)) {
return smbd_smb2_request_error(req, NT_STATUS_INVALID_PARAMETER);
}
in_path_buffer.data = SMBD_SMB2_IN_DYN_PTR(req);
in_path_buffer.length = in_path_length;
ok = convert_string_talloc(req, CH_UTF16, CH_UNIX,
in_path_buffer.data,
in_path_buffer.length,
&in_path_string,
&in_path_string_size);
if (!ok) {
return smbd_smb2_request_error(req, NT_STATUS_ILLEGAL_CHARACTER);
}
if (in_path_buffer.length == 0) {
in_path_string_size = 0;
}
if (strlen(in_path_string) != in_path_string_size) {
return smbd_smb2_request_error(req, NT_STATUS_BAD_NETWORK_NAME);
}
subreq = smbd_smb2_tree_connect_send(req,
req->sconn->ev_ctx,
req,
in_path_string);
if (subreq == NULL) {
return smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
}
tevent_req_set_callback(subreq, smbd_smb2_request_tcon_done, req);
return smbd_smb2_request_pending_queue(req, subreq, 500);
}
static void smbd_smb2_request_tcon_done(struct tevent_req *subreq)
{
struct smbd_smb2_request *req =
tevent_req_callback_data(subreq,
struct smbd_smb2_request);
uint8_t *outhdr;
DATA_BLOB outbody;
uint8_t out_share_type = 0;
uint32_t out_share_flags = 0;
uint32_t out_capabilities = 0;
uint32_t out_maximal_access = 0;
uint32_t out_tree_id = 0;
bool disconnect = false;
NTSTATUS status;
NTSTATUS error;
status = smbd_smb2_tree_connect_recv(subreq,
&out_share_type,
&out_share_flags,
&out_capabilities,
&out_maximal_access,
&out_tree_id,
&disconnect);
TALLOC_FREE(subreq);
if (!NT_STATUS_IS_OK(status)) {
if (disconnect) {
smbd_server_connection_terminate(req->xconn,
nt_errstr(status));
return;
}
error = smbd_smb2_request_error(req, status);
if (!NT_STATUS_IS_OK(error)) {
smbd_server_connection_terminate(req->xconn,
nt_errstr(error));
return;
}
return;
}
outhdr = SMBD_SMB2_OUT_HDR_PTR(req);
outbody = smbd_smb2_generate_outbody(req, 0x10);
if (outbody.data == NULL) {
error = smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
if (!NT_STATUS_IS_OK(error)) {
smbd_server_connection_terminate(req->xconn,
nt_errstr(error));
return;
}
return;
}
SIVAL(outhdr, SMB2_HDR_TID, out_tree_id);
SSVAL(outbody.data, 0x00, 0x10); /* struct size */
SCVAL(outbody.data, 0x02,
out_share_type); /* share type */
SCVAL(outbody.data, 0x03, 0); /* reserved */
SIVAL(outbody.data, 0x04,
out_share_flags); /* share flags */
SIVAL(outbody.data, 0x08,
out_capabilities); /* capabilities */
SIVAL(outbody.data, 0x0C,
out_maximal_access); /* maximal access */
error = smbd_smb2_request_done(req, outbody, NULL);
if (!NT_STATUS_IS_OK(error)) {
smbd_server_connection_terminate(req->xconn,
nt_errstr(error));
return;
}
}
static NTSTATUS smbd_smb2_tree_connect(struct smbd_smb2_request *req,
const char *in_path,
uint8_t *out_share_type,
uint32_t *out_share_flags,
uint32_t *out_capabilities,
uint32_t *out_maximal_access,
uint32_t *out_tree_id,
bool *disconnect)
{
struct smbXsrv_connection *conn = req->xconn;
const char *share = in_path;
char *service = NULL;
int snum = -1;
struct smbXsrv_tcon *tcon;
NTTIME now = timeval_to_nttime(&req->request_time);
connection_struct *compat_conn = NULL;
struct user_struct *compat_vuser = req->session->compat;
NTSTATUS status;
bool encryption_desired = req->session->global->encryption_flags & SMBXSRV_ENCRYPTION_DESIRED;
bool encryption_required = req->session->global->encryption_flags & SMBXSRV_ENCRYPTION_REQUIRED;
bool guest_session = false;
bool require_signed_tcon = false;
*disconnect = false;
if (strncmp(share, "\\\\", 2) == 0) {
const char *p = strchr(share+2, '\\');
if (p) {
share = p + 1;
}
}
DEBUG(10,("smbd_smb2_tree_connect: path[%s] share[%s]\n",
in_path, share));
if (security_session_user_level(compat_vuser->session_info, NULL) < SECURITY_USER) {
guest_session = true;
}
if (conn->protocol >= PROTOCOL_SMB3_11 && !guest_session) {
require_signed_tcon = true;
}
if (require_signed_tcon && !req->do_encryption && !req->do_signing) {
DEBUG(1, ("smbd_smb2_tree_connect: reject request to share "
"[%s] as '%s\\%s' without encryption or signing. "
"Disconnecting.\n",
share,
req->session->global->auth_session_info->info->domain_name,
req->session->global->auth_session_info->info->account_name));
*disconnect = true;
return NT_STATUS_ACCESS_DENIED;
}
service = talloc_strdup(talloc_tos(), share);
if(!service) {
return NT_STATUS_NO_MEMORY;
}
if (!strlower_m(service)) {
DEBUG(2, ("strlower_m %s failed\n", service));
return NT_STATUS_INVALID_PARAMETER;
}
/* TODO: do more things... */
if (strequal(service,HOMES_NAME)) {
if (compat_vuser->homes_snum == -1) {
DEBUG(2, ("[homes] share not available for "
"user %s because it was not found "
"or created at session setup "
"time\n",
compat_vuser->session_info->unix_info->unix_name));
return NT_STATUS_BAD_NETWORK_NAME;
}
snum = compat_vuser->homes_snum;
} else if ((compat_vuser->homes_snum != -1)
&& strequal(service,
lp_servicename(talloc_tos(), compat_vuser->homes_snum))) {
snum = compat_vuser->homes_snum;
} else {
snum = find_service(talloc_tos(), service, &service);
if (!service) {
return NT_STATUS_NO_MEMORY;
}
}
if (snum < 0) {
DEBUG(3,("smbd_smb2_tree_connect: couldn't find service %s\n",
service));
return NT_STATUS_BAD_NETWORK_NAME;
}
/* Handle non-DFS clients attempting connections to msdfs proxy */
if (lp_host_msdfs()) {
char *proxy = lp_msdfs_proxy(talloc_tos(), snum);
if ((proxy != NULL) && (*proxy != '\0')) {
DBG_NOTICE("refusing connection to dfs proxy share "
"'%s' (pointing to %s)\n",
service,
proxy);
TALLOC_FREE(proxy);
return NT_STATUS_BAD_NETWORK_NAME;
}
TALLOC_FREE(proxy);
}
if ((lp_smb_encrypt(snum) >= SMB_SIGNING_DESIRED) &&
(conn->smb2.server.cipher != 0))
{
encryption_desired = true;
}
if (lp_smb_encrypt(snum) == SMB_SIGNING_REQUIRED) {
encryption_desired = true;
encryption_required = true;
}
if (guest_session && encryption_required) {
DEBUG(1,("reject guest as encryption is required for service %s\n",
service));
return NT_STATUS_ACCESS_DENIED;
}
if (conn->smb2.server.cipher == 0) {
if (encryption_required) {
DEBUG(1,("reject tcon with dialect[0x%04X] "
"as encryption is required for service %s\n",
conn->smb2.server.dialect, service));
return NT_STATUS_ACCESS_DENIED;
}
}
/* create a new tcon as child of the session */
status = smb2srv_tcon_create(req->session, now, &tcon);
if (!NT_STATUS_IS_OK(status)) {
return status;
}
if (encryption_desired) {
tcon->global->encryption_flags |= SMBXSRV_ENCRYPTION_DESIRED;
}
if (encryption_required) {
tcon->global->encryption_flags |= SMBXSRV_ENCRYPTION_REQUIRED;
}
compat_conn = make_connection_smb2(req,
tcon, snum,
req->session->compat,
"???",
&status);
if (compat_conn == NULL) {
TALLOC_FREE(tcon);
return status;
}
tcon->global->share_name = lp_servicename(tcon->global,
SNUM(compat_conn));
if (tcon->global->share_name == NULL) {
conn_free(compat_conn);
TALLOC_FREE(tcon);
return NT_STATUS_NO_MEMORY;
}
tcon->global->session_global_id =
req->session->global->session_global_id;
tcon->compat = talloc_move(tcon, &compat_conn);
tcon->status = NT_STATUS_OK;
status = smbXsrv_tcon_update(tcon);
if (!NT_STATUS_IS_OK(status)) {
TALLOC_FREE(tcon);
return status;
}
if (IS_PRINT(tcon->compat)) {
*out_share_type = SMB2_SHARE_TYPE_PRINT;
} else if (IS_IPC(tcon->compat)) {
*out_share_type = SMB2_SHARE_TYPE_PIPE;
} else {
*out_share_type = SMB2_SHARE_TYPE_DISK;
}
*out_share_flags = 0;
if (lp_msdfs_root(SNUM(tcon->compat)) && lp_host_msdfs()) {
*out_share_flags |= (SMB2_SHAREFLAG_DFS|SMB2_SHAREFLAG_DFS_ROOT);
*out_capabilities = SMB2_SHARE_CAP_DFS;
} else {
*out_capabilities = 0;
}
switch(lp_csc_policy(SNUM(tcon->compat))) {
case CSC_POLICY_MANUAL:
break;
case CSC_POLICY_DOCUMENTS:
*out_share_flags |= SMB2_SHAREFLAG_AUTO_CACHING;
break;
case CSC_POLICY_PROGRAMS:
*out_share_flags |= SMB2_SHAREFLAG_VDO_CACHING;
break;
case CSC_POLICY_DISABLE:
*out_share_flags |= SMB2_SHAREFLAG_NO_CACHING;
break;
default:
break;
}
if (lp_hide_unreadable(SNUM(tcon->compat)) ||
lp_hide_unwriteable_files(SNUM(tcon->compat))) {
*out_share_flags |= SMB2_SHAREFLAG_ACCESS_BASED_DIRECTORY_ENUM;
}
if (encryption_desired) {
*out_share_flags |= SMB2_SHAREFLAG_ENCRYPT_DATA;
}
*out_maximal_access = tcon->compat->share_access;
*out_tree_id = tcon->global->tcon_wire_id;
req->last_tid = tcon->global->tcon_wire_id;
return NT_STATUS_OK;
}
struct smbd_smb2_tree_connect_state {
const char *in_path;
uint8_t out_share_type;
uint32_t out_share_flags;
uint32_t out_capabilities;
uint32_t out_maximal_access;
uint32_t out_tree_id;
bool disconnect;
};
static struct tevent_req *smbd_smb2_tree_connect_send(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
struct smbd_smb2_request *smb2req,
const char *in_path)
{
struct tevent_req *req;
struct smbd_smb2_tree_connect_state *state;
NTSTATUS status;
req = tevent_req_create(mem_ctx, &state,
struct smbd_smb2_tree_connect_state);
if (req == NULL) {
return NULL;
}
state->in_path = in_path;
status = smbd_smb2_tree_connect(smb2req,
state->in_path,
&state->out_share_type,
&state->out_share_flags,
&state->out_capabilities,
&state->out_maximal_access,
&state->out_tree_id,
&state->disconnect);
if (tevent_req_nterror(req, status)) {
return tevent_req_post(req, ev);
}
tevent_req_done(req);
return tevent_req_post(req, ev);
}
static NTSTATUS smbd_smb2_tree_connect_recv(struct tevent_req *req,
uint8_t *out_share_type,
uint32_t *out_share_flags,
uint32_t *out_capabilities,
uint32_t *out_maximal_access,
uint32_t *out_tree_id,
bool *disconnect)
{
struct smbd_smb2_tree_connect_state *state =
tevent_req_data(req,
struct smbd_smb2_tree_connect_state);
NTSTATUS status;
if (tevent_req_is_nterror(req, &status)) {
tevent_req_received(req);
return status;
}
*out_share_type = state->out_share_type;
*out_share_flags = state->out_share_flags;
*out_capabilities = state->out_capabilities;
*out_maximal_access = state->out_maximal_access;
*out_tree_id = state->out_tree_id;
*disconnect = state->disconnect;
tevent_req_received(req);
return NT_STATUS_OK;
}
static struct tevent_req *smbd_smb2_tdis_send(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
struct smbd_smb2_request *smb2req);
static NTSTATUS smbd_smb2_tdis_recv(struct tevent_req *req);
static void smbd_smb2_request_tdis_done(struct tevent_req *subreq);
NTSTATUS smbd_smb2_request_process_tdis(struct smbd_smb2_request *req)
{
NTSTATUS status;
struct tevent_req *subreq = NULL;
status = smbd_smb2_request_verify_sizes(req, 0x04);
if (!NT_STATUS_IS_OK(status)) {
return smbd_smb2_request_error(req, status);
}
subreq = smbd_smb2_tdis_send(req, req->sconn->ev_ctx, req);
if (subreq == NULL) {
return smbd_smb2_request_error(req, NT_STATUS_NO_MEMORY);
}
tevent_req_set_callback(subreq, smbd_smb2_request_tdis_done, req);
/*
* Wait a long time before going async on this to allow
* requests we're waiting on to finish. Set timeout to 10 secs.
*/
return smbd_smb2_request_pending_queue(req, subreq, 10000000);
}
static void smbd_smb2_request_tdis_done(struct tevent_req *subreq)
{
struct smbd_smb2_request *smb2req =
tevent_req_callback_data(subreq,
struct smbd_smb2_request);
DATA_BLOB outbody;
NTSTATUS status;
NTSTATUS error;
status = smbd_smb2_tdis_recv(subreq);
TALLOC_FREE(subreq);
if (!NT_STATUS_IS_OK(status)) {
error = smbd_smb2_request_error(smb2req, status);
if (!NT_STATUS_IS_OK(error)) {
smbd_server_connection_terminate(smb2req->xconn,
nt_errstr(error));
return;
}
return;
}
outbody = smbd_smb2_generate_outbody(smb2req, 0x04);
if (outbody.data == NULL) {
error = smbd_smb2_request_error(smb2req, NT_STATUS_NO_MEMORY);
if (!NT_STATUS_IS_OK(error)) {
smbd_server_connection_terminate(smb2req->xconn,
nt_errstr(error));
return;
}
return;
}
SSVAL(outbody.data, 0x00, 0x04); /* struct size */
SSVAL(outbody.data, 0x02, 0); /* reserved */
error = smbd_smb2_request_done(smb2req, outbody, NULL);
if (!NT_STATUS_IS_OK(error)) {
smbd_server_connection_terminate(smb2req->xconn,
nt_errstr(error));
return;
}
}
struct smbd_smb2_tdis_state {
struct smbd_smb2_request *smb2req;
struct tevent_queue *wait_queue;
};
static void smbd_smb2_tdis_wait_done(struct tevent_req *subreq);
static struct tevent_req *smbd_smb2_tdis_send(TALLOC_CTX *mem_ctx,
struct tevent_context *ev,
struct smbd_smb2_request *smb2req)
{
struct tevent_req *req;
struct smbd_smb2_tdis_state *state;
struct tevent_req *subreq;
struct smbXsrv_connection *xconn = NULL;
req = tevent_req_create(mem_ctx, &state,
struct smbd_smb2_tdis_state);
if (req == NULL) {
return NULL;
}
state->smb2req = smb2req;
state->wait_queue = tevent_queue_create(state, "tdis_wait_queue");
if (tevent_req_nomem(state->wait_queue, req)) {
return tevent_req_post(req, ev);
}
/*
* Make sure that no new request will be able to use this tcon.
*/
smb2req->tcon->status = NT_STATUS_NETWORK_NAME_DELETED;
xconn = smb2req->xconn->client->connections;
for (; xconn != NULL; xconn = xconn->next) {
struct smbd_smb2_request *preq;
for (preq = xconn->smb2.requests; preq != NULL; preq = preq->next) {
if (preq == smb2req) {
/* Can't cancel current request. */
continue;
}
if (preq->tcon != smb2req->tcon) {
/* Request on different tcon. */
continue;
}
/*
* Never cancel anything in a compound
* request. Way too hard to deal with
* the result.
*/
if (!preq->compound_related && preq->subreq != NULL) {
tevent_req_cancel(preq->subreq);
}
/*
* Now wait until the request is finished.
*
* We don't set a callback, as we just want to block the
* wait queue and the talloc_free() of the request will
* remove the item from the wait queue.
*/
subreq = tevent_queue_wait_send(preq, ev, state->wait_queue);
if (tevent_req_nomem(subreq, req)) {
return tevent_req_post(req, ev);
}
}
}
/*
* Now we add our own waiter to the end of the queue,
* this way we get notified when all pending requests are finished
* and send to the socket.
*/
subreq = tevent_queue_wait_send(state, ev, state->wait_queue);
if (tevent_req_nomem(subreq, req)) {
return tevent_req_post(req, ev);
}
tevent_req_set_callback(subreq, smbd_smb2_tdis_wait_done, req);
return req;
}
static void smbd_smb2_tdis_wait_done(struct tevent_req *subreq)
{
struct tevent_req *req = tevent_req_callback_data(
subreq, struct tevent_req);
struct smbd_smb2_tdis_state *state = tevent_req_data(
req, struct smbd_smb2_tdis_state);
NTSTATUS status;
tevent_queue_wait_recv(subreq);
TALLOC_FREE(subreq);
/*
* As we've been awoken, we may have changed
* uid in the meantime. Ensure we're still
* root (SMB2_OP_TDIS has .as_root = true).
*/
change_to_root_user();
status = smbXsrv_tcon_disconnect(state->smb2req->tcon,
state->smb2req->tcon->compat->vuid);
if (tevent_req_nterror(req, status)) {
return;
}
/* We did tear down the tcon. */
TALLOC_FREE(state->smb2req->tcon);
tevent_req_done(req);
}
static NTSTATUS smbd_smb2_tdis_recv(struct tevent_req *req)
{
return tevent_req_simple_recv_ntstatus(req);
}