/*
Unix SMB/CIFS implementation.
SMB Transport encryption (sealing) code - server code.
Copyright (C) Jeremy Allison 2007.
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 .
*/
#include "includes.h"
#include "smbd/smbd.h"
#include "smbd/globals.h"
#include "../libcli/auth/spnego.h"
#include "../libcli/smb/smb_seal.h"
#include "../lib/util/asn1.h"
#include "auth.h"
#include "libsmb/libsmb.h"
#include "../lib/tsocket/tsocket.h"
#include "auth/gensec/gensec.h"
/******************************************************************************
Server side encryption.
******************************************************************************/
/******************************************************************************
Return global enc context - this must change if we ever do multiple contexts.
******************************************************************************/
static uint16_t srv_enc_ctx(const struct smb_trans_enc_state *es)
{
return es->enc_ctx_num;
}
/******************************************************************************
Is this an incoming encrypted packet ?
******************************************************************************/
bool is_encrypted_packet(struct smbd_server_connection *sconn,
const uint8_t *inbuf)
{
NTSTATUS status;
uint16_t enc_num;
/* Ignore non-session messages or non 0xFF'E' messages. */
if(CVAL(inbuf,0)
|| (smb_len(inbuf) < 8)
|| !(inbuf[4] == 0xFF && inbuf[5] == 'E')) {
return false;
}
status = get_enc_ctx_num(inbuf, &enc_num);
if (!NT_STATUS_IS_OK(status)) {
return false;
}
/* Encrypted messages are 0xFF'E' */
if (srv_trans_enc_ctx && enc_num == srv_enc_ctx(srv_trans_enc_ctx)) {
return true;
}
return false;
}
/******************************************************************************
Create an gensec_security and ensure pointer copy is correct.
******************************************************************************/
static NTSTATUS make_auth_gensec(const struct tsocket_address *remote_address,
struct smb_trans_enc_state *es, const char *oid)
{
struct gensec_security *gensec_security;
NTSTATUS status = auth_generic_prepare(NULL, remote_address,
&gensec_security);
if (!NT_STATUS_IS_OK(status)) {
return nt_status_squash(status);
}
gensec_want_feature(gensec_security, GENSEC_FEATURE_SEAL);
/*
* We could be accessing the secrets.tdb or krb5.keytab file here.
* ensure we have permissions to do so.
*/
become_root();
status = gensec_start_mech_by_oid(gensec_security, oid);
unbecome_root();
if (!NT_STATUS_IS_OK(status)) {
TALLOC_FREE(gensec_security);
return nt_status_squash(status);
}
es->s.gensec_security = gensec_security;
return status;
}
/******************************************************************************
Shutdown a server encryption context.
******************************************************************************/
static void srv_free_encryption_context(struct smb_trans_enc_state **pp_es)
{
struct smb_trans_enc_state *es = *pp_es;
if (!es) {
return;
}
common_free_encryption_state(&es);
SAFE_FREE(es);
*pp_es = NULL;
}
/******************************************************************************
Create a server encryption context.
******************************************************************************/
static NTSTATUS make_srv_encryption_context(const struct tsocket_address *remote_address,
enum smb_trans_enc_type smb_enc_type,
struct smb_trans_enc_state **pp_es)
{
NTSTATUS status;
const char *oid;
struct smb_trans_enc_state *es;
*pp_es = NULL;
ZERO_STRUCTP(partial_srv_trans_enc_ctx);
es = SMB_MALLOC_P(struct smb_trans_enc_state);
if (!es) {
return NT_STATUS_NO_MEMORY;
}
ZERO_STRUCTP(es);
es->smb_enc_type = smb_enc_type;
switch (smb_enc_type) {
case SMB_TRANS_ENC_NTLM:
oid = GENSEC_OID_NTLMSSP;
break;
case SMB_TRANS_ENC_GSS:
oid = GENSEC_OID_KERBEROS5;
break;
default:
srv_free_encryption_context(&es);
return NT_STATUS_INVALID_PARAMETER;
}
status = make_auth_gensec(remote_address,
es, oid);
if (!NT_STATUS_IS_OK(status)) {
srv_free_encryption_context(&es);
return status;
}
*pp_es = es;
return NT_STATUS_OK;
}
/******************************************************************************
Free an encryption-allocated buffer.
******************************************************************************/
void srv_free_enc_buffer(struct smbd_server_connection *sconn, char *buf)
{
/* We know this is an smb buffer, and we
* didn't malloc, only copy, for a keepalive,
* so ignore non-session messages. */
if(CVAL(buf,0)) {
return;
}
if (srv_trans_enc_ctx) {
common_free_enc_buffer(srv_trans_enc_ctx, buf);
}
}
/******************************************************************************
Decrypt an incoming buffer.
******************************************************************************/
NTSTATUS srv_decrypt_buffer(struct smbd_server_connection *sconn, char *buf)
{
/* Ignore non-session messages. */
if(CVAL(buf,0)) {
return NT_STATUS_OK;
}
if (srv_trans_enc_ctx) {
return common_decrypt_buffer(srv_trans_enc_ctx, buf);
}
return NT_STATUS_OK;
}
/******************************************************************************
Encrypt an outgoing buffer. Return the encrypted pointer in buf_out.
******************************************************************************/
NTSTATUS srv_encrypt_buffer(struct smbd_server_connection *sconn, char *buf,
char **buf_out)
{
*buf_out = buf;
/* Ignore non-session messages. */
if(CVAL(buf,0)) {
return NT_STATUS_OK;
}
if (srv_trans_enc_ctx) {
return common_encrypt_buffer(srv_trans_enc_ctx, buf, buf_out);
}
/* Not encrypting. */
return NT_STATUS_OK;
}
/******************************************************************************
Do the gss encryption negotiation. Parameters are in/out.
Until success we do everything on the partial enc ctx.
******************************************************************************/
static NTSTATUS srv_enc_spnego_gss_negotiate(const struct tsocket_address *remote_address,
unsigned char **ppdata,
size_t *p_data_size,
DATA_BLOB secblob)
{
NTSTATUS status;
DATA_BLOB unwrapped_response = data_blob_null;
DATA_BLOB response = data_blob_null;
status = make_srv_encryption_context(remote_address,
SMB_TRANS_ENC_GSS,
&partial_srv_trans_enc_ctx);
if (!NT_STATUS_IS_OK(status)) {
return status;
}
become_root();
status = gensec_update(partial_srv_trans_enc_ctx->s.gensec_security,
talloc_tos(), NULL,
secblob, &unwrapped_response);
unbecome_root();
/* status here should be NT_STATUS_MORE_PROCESSING_REQUIRED
* for success ... */
response = spnego_gen_auth_response(talloc_tos(), &unwrapped_response, status, OID_KERBEROS5);
data_blob_free(&unwrapped_response);
SAFE_FREE(*ppdata);
*ppdata = (unsigned char *)memdup(response.data, response.length);
if ((*ppdata) == NULL && response.length > 0) {
status = NT_STATUS_NO_MEMORY;
}
*p_data_size = response.length;
data_blob_free(&response);
return status;
}
/******************************************************************************
Do the NTLM SPNEGO (or raw) encryption negotiation. Parameters are in/out.
Until success we do everything on the partial enc ctx.
******************************************************************************/
static NTSTATUS srv_enc_ntlm_negotiate(const struct tsocket_address *remote_address,
unsigned char **ppdata,
size_t *p_data_size,
DATA_BLOB secblob,
bool spnego_wrap)
{
NTSTATUS status;
DATA_BLOB chal = data_blob_null;
DATA_BLOB response = data_blob_null;
status = make_srv_encryption_context(remote_address,
SMB_TRANS_ENC_NTLM,
&partial_srv_trans_enc_ctx);
if (!NT_STATUS_IS_OK(status)) {
return status;
}
status = gensec_update(partial_srv_trans_enc_ctx->s.gensec_security,
talloc_tos(), NULL,
secblob, &chal);
/* status here should be NT_STATUS_MORE_PROCESSING_REQUIRED
* for success ... */
if (spnego_wrap) {
response = spnego_gen_auth_response(talloc_tos(), &chal, status, OID_NTLMSSP);
data_blob_free(&chal);
} else {
/* Return the raw blob. */
response = chal;
}
SAFE_FREE(*ppdata);
*ppdata = (unsigned char *)memdup(response.data, response.length);
if ((*ppdata) == NULL && response.length > 0) {
status = NT_STATUS_NO_MEMORY;
}
*p_data_size = response.length;
data_blob_free(&response);
return status;
}
/******************************************************************************
Do the SPNEGO encryption negotiation. Parameters are in/out.
Based off code in smbd/sesssionsetup.c
Until success we do everything on the partial enc ctx.
******************************************************************************/
static NTSTATUS srv_enc_spnego_negotiate(connection_struct *conn,
unsigned char **ppdata,
size_t *p_data_size,
unsigned char **pparam,
size_t *p_param_size)
{
NTSTATUS status;
DATA_BLOB blob = data_blob_null;
DATA_BLOB secblob = data_blob_null;
char *kerb_mech = NULL;
blob = data_blob_const(*ppdata, *p_data_size);
status = parse_spnego_mechanisms(talloc_tos(), blob, &secblob, &kerb_mech);
if (!NT_STATUS_IS_OK(status)) {
return nt_status_squash(status);
}
/* We should have no partial context at this point. */
srv_free_encryption_context(&partial_srv_trans_enc_ctx);
if (kerb_mech) {
TALLOC_FREE(kerb_mech);
status = srv_enc_spnego_gss_negotiate(conn->sconn->remote_address,
ppdata,
p_data_size,
secblob);
} else {
status = srv_enc_ntlm_negotiate(conn->sconn->remote_address,
ppdata,
p_data_size,
secblob,
true);
}
data_blob_free(&secblob);
if (!NT_STATUS_EQUAL(status,NT_STATUS_MORE_PROCESSING_REQUIRED) && !NT_STATUS_IS_OK(status)) {
srv_free_encryption_context(&partial_srv_trans_enc_ctx);
return nt_status_squash(status);
}
if (NT_STATUS_IS_OK(status)) {
/* Return the context we're using for this encryption state. */
if (!(*pparam = SMB_MALLOC_ARRAY(unsigned char, 2))) {
return NT_STATUS_NO_MEMORY;
}
SSVAL(*pparam,0,partial_srv_trans_enc_ctx->enc_ctx_num);
*p_param_size = 2;
}
return status;
}
/******************************************************************************
Complete a SPNEGO encryption negotiation. Parameters are in/out.
We only get this for a NTLM auth second stage.
******************************************************************************/
static NTSTATUS srv_enc_spnego_ntlm_auth(connection_struct *conn,
unsigned char **ppdata,
size_t *p_data_size,
unsigned char **pparam,
size_t *p_param_size)
{
NTSTATUS status;
DATA_BLOB blob = data_blob_null;
DATA_BLOB auth = data_blob_null;
DATA_BLOB auth_reply = data_blob_null;
DATA_BLOB response = data_blob_null;
struct smb_trans_enc_state *es = partial_srv_trans_enc_ctx;
/* We must have a partial context here. */
if (!es || es->s.gensec_security == NULL || es->smb_enc_type != SMB_TRANS_ENC_NTLM) {
srv_free_encryption_context(&partial_srv_trans_enc_ctx);
return NT_STATUS_INVALID_PARAMETER;
}
blob = data_blob_const(*ppdata, *p_data_size);
if (!spnego_parse_auth(talloc_tos(), blob, &auth)) {
srv_free_encryption_context(&partial_srv_trans_enc_ctx);
return NT_STATUS_INVALID_PARAMETER;
}
status = gensec_update(es->s.gensec_security, talloc_tos(), NULL, auth, &auth_reply);
data_blob_free(&auth);
/* From RFC4178.
*
* supportedMech
*
* This field SHALL only be present in the first reply from the
* target.
* So set mechOID to NULL here.
*/
response = spnego_gen_auth_response(talloc_tos(), &auth_reply, status, NULL);
data_blob_free(&auth_reply);
if (NT_STATUS_IS_OK(status)) {
/* Return the context we're using for this encryption state. */
if (!(*pparam = SMB_MALLOC_ARRAY(unsigned char, 2))) {
return NT_STATUS_NO_MEMORY;
}
SSVAL(*pparam,0,es->enc_ctx_num);
*p_param_size = 2;
}
SAFE_FREE(*ppdata);
*ppdata = (unsigned char *)memdup(response.data, response.length);
if ((*ppdata) == NULL && response.length > 0)
return NT_STATUS_NO_MEMORY;
*p_data_size = response.length;
data_blob_free(&response);
return status;
}
/******************************************************************************
Raw NTLM encryption negotiation. Parameters are in/out.
This function does both steps.
******************************************************************************/
static NTSTATUS srv_enc_raw_ntlm_auth(connection_struct *conn,
unsigned char **ppdata,
size_t *p_data_size,
unsigned char **pparam,
size_t *p_param_size)
{
NTSTATUS status;
DATA_BLOB blob = data_blob_const(*ppdata, *p_data_size);
DATA_BLOB response = data_blob_null;
struct smb_trans_enc_state *es;
if (!partial_srv_trans_enc_ctx) {
/* This is the initial step. */
status = srv_enc_ntlm_negotiate(conn->sconn->remote_address,
ppdata,
p_data_size,
blob,
false);
if (!NT_STATUS_EQUAL(status,NT_STATUS_MORE_PROCESSING_REQUIRED) && !NT_STATUS_IS_OK(status)) {
srv_free_encryption_context(&partial_srv_trans_enc_ctx);
return nt_status_squash(status);
}
return status;
}
es = partial_srv_trans_enc_ctx;
if (!es || es->s.gensec_security == NULL || es->smb_enc_type != SMB_TRANS_ENC_NTLM) {
srv_free_encryption_context(&partial_srv_trans_enc_ctx);
return NT_STATUS_INVALID_PARAMETER;
}
/* Second step. */
status = gensec_update(partial_srv_trans_enc_ctx->s.gensec_security,
talloc_tos(), NULL,
blob, &response);
if (NT_STATUS_IS_OK(status)) {
/* Return the context we're using for this encryption state. */
if (!(*pparam = SMB_MALLOC_ARRAY(unsigned char, 2))) {
return NT_STATUS_NO_MEMORY;
}
SSVAL(*pparam, 0, es->enc_ctx_num);
*p_param_size = 2;
}
/* Return the raw blob. */
SAFE_FREE(*ppdata);
*ppdata = (unsigned char *)memdup(response.data, response.length);
if ((*ppdata) == NULL && response.length > 0)
return NT_STATUS_NO_MEMORY;
*p_data_size = response.length;
data_blob_free(&response);
return status;
}
/******************************************************************************
Do the SPNEGO encryption negotiation. Parameters are in/out.
******************************************************************************/
NTSTATUS srv_request_encryption_setup(connection_struct *conn,
unsigned char **ppdata,
size_t *p_data_size,
unsigned char **pparam,
size_t *p_param_size)
{
unsigned char *pdata = *ppdata;
SAFE_FREE(*pparam);
*p_param_size = 0;
if (*p_data_size < 1) {
return NT_STATUS_INVALID_PARAMETER;
}
if (pdata[0] == ASN1_APPLICATION(0)) {
/* its a negTokenTarg packet */
return srv_enc_spnego_negotiate(conn, ppdata, p_data_size, pparam, p_param_size);
}
if (pdata[0] == ASN1_CONTEXT(1)) {
/* It's an auth packet */
return srv_enc_spnego_ntlm_auth(conn, ppdata, p_data_size, pparam, p_param_size);
}
/* Maybe it's a raw unwrapped auth ? */
if (*p_data_size < 7) {
return NT_STATUS_INVALID_PARAMETER;
}
if (strncmp((char *)pdata, "NTLMSSP", 7) == 0) {
return srv_enc_raw_ntlm_auth(conn, ppdata, p_data_size, pparam, p_param_size);
}
DEBUG(1,("srv_request_encryption_setup: Unknown packet\n"));
return NT_STATUS_LOGON_FAILURE;
}
/******************************************************************************
Negotiation was successful - turn on server-side encryption.
******************************************************************************/
static NTSTATUS check_enc_good(struct smb_trans_enc_state *es)
{
if (!es) {
return NT_STATUS_LOGON_FAILURE;
}
if (es->smb_enc_type == SMB_TRANS_ENC_NTLM) {
if (!gensec_have_feature(es->s.gensec_security, GENSEC_FEATURE_SIGN)) {
return NT_STATUS_INVALID_PARAMETER;
}
if (!gensec_have_feature(es->s.gensec_security, GENSEC_FEATURE_SEAL)) {
return NT_STATUS_INVALID_PARAMETER;
}
}
/* Todo - check gssapi case. */
return NT_STATUS_OK;
}
/******************************************************************************
Negotiation was successful - turn on server-side encryption.
******************************************************************************/
NTSTATUS srv_encryption_start(connection_struct *conn)
{
NTSTATUS status;
/* Check that we are really doing sign+seal. */
status = check_enc_good(partial_srv_trans_enc_ctx);
if (!NT_STATUS_IS_OK(status)) {
return status;
}
/* Throw away the context we're using currently (if any). */
srv_free_encryption_context(&srv_trans_enc_ctx);
/* Steal the partial pointer. Deliberate shallow copy. */
srv_trans_enc_ctx = partial_srv_trans_enc_ctx;
srv_trans_enc_ctx->enc_on = true;
partial_srv_trans_enc_ctx = NULL;
DEBUG(1,("srv_encryption_start: context negotiated\n"));
return NT_STATUS_OK;
}
/******************************************************************************
Shutdown all server contexts.
******************************************************************************/
void server_encryption_shutdown(struct smbd_server_connection *sconn)
{
srv_free_encryption_context(&partial_srv_trans_enc_ctx);
srv_free_encryption_context(&srv_trans_enc_ctx);
}