1
0
mirror of https://github.com/samba-team/samba.git synced 2024-12-27 03:21:53 +03:00
samba-mirror/source3/smbd/seal.c

762 lines
22 KiB
C

/*
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 <http://www.gnu.org/licenses/>.
*/
#include "includes.h"
#include "smbd/globals.h"
#include "../libcli/auth/spnego.h"
#include "../libcli/auth/ntlmssp.h"
#include "ntlmssp_wrap.h"
/******************************************************************************
Server side encryption.
******************************************************************************/
/******************************************************************************
Global server state.
******************************************************************************/
struct smb_srv_trans_enc_ctx {
struct smb_trans_enc_state *es;
struct auth_ntlmssp_state *auth_ntlmssp_state; /* Must be kept in sync with pointer in ec->ntlmssp_state. */
};
/******************************************************************************
Return global enc context - this must change if we ever do multiple contexts.
******************************************************************************/
uint16_t srv_enc_ctx(void)
{
return srv_trans_enc_ctx->es->enc_ctx_num;
}
/******************************************************************************
Is this an incoming encrypted packet ?
******************************************************************************/
bool is_encrypted_packet(const uint8_t *inbuf)
{
NTSTATUS status;
uint16_t enc_num;
/* Ignore non-session messages or non 0xFF'E' messages. */
if(CVAL(inbuf,0) || !(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'<ctx> */
if (srv_trans_enc_ctx && enc_num == srv_enc_ctx()) {
return true;
}
return false;
}
/******************************************************************************
Create an auth_ntlmssp_state and ensure pointer copy is correct.
******************************************************************************/
static NTSTATUS make_auth_ntlmssp(struct smb_srv_trans_enc_ctx *ec)
{
NTSTATUS status = auth_ntlmssp_start(&ec->auth_ntlmssp_state);
if (!NT_STATUS_IS_OK(status)) {
return nt_status_squash(status);
}
/*
* We must remember to update the pointer copy for the common
* functions after any auth_ntlmssp_start/auth_ntlmssp_end.
*/
ec->es->s.ntlmssp_state = auth_ntlmssp_get_ntlmssp_state(ec->auth_ntlmssp_state);
return status;
}
/******************************************************************************
Destroy an auth_ntlmssp_state and ensure pointer copy is correct.
******************************************************************************/
static void destroy_auth_ntlmssp(struct smb_srv_trans_enc_ctx *ec)
{
/*
* We must remember to update the pointer copy for the common
* functions after any auth_ntlmssp_start/auth_ntlmssp_end.
*/
if (ec->auth_ntlmssp_state) {
TALLOC_FREE(ec->auth_ntlmssp_state);
/* The auth_ntlmssp_end killed this already. */
ec->es->s.ntlmssp_state = NULL;
}
}
#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
/******************************************************************************
Import a name.
******************************************************************************/
static NTSTATUS get_srv_gss_creds(const char *service,
const char *name,
gss_cred_usage_t cred_type,
gss_cred_id_t *p_srv_cred)
{
OM_uint32 ret;
OM_uint32 min;
gss_name_t srv_name;
gss_buffer_desc input_name;
char *host_princ_s = NULL;
NTSTATUS status = NT_STATUS_OK;
gss_OID_desc nt_hostbased_service =
{10, CONST_DISCARD(char *,"\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x04")};
if (asprintf(&host_princ_s, "%s@%s", service, name) == -1) {
return NT_STATUS_NO_MEMORY;
}
input_name.value = host_princ_s;
input_name.length = strlen(host_princ_s) + 1;
ret = gss_import_name(&min,
&input_name,
&nt_hostbased_service,
&srv_name);
DEBUG(10,("get_srv_gss_creds: imported name %s\n",
host_princ_s ));
if (ret != GSS_S_COMPLETE) {
SAFE_FREE(host_princ_s);
return map_nt_error_from_gss(ret, min);
}
/*
* We're accessing the krb5.keytab file here.
* ensure we have permissions to do so.
*/
become_root();
ret = gss_acquire_cred(&min,
srv_name,
GSS_C_INDEFINITE,
GSS_C_NULL_OID_SET,
cred_type,
p_srv_cred,
NULL,
NULL);
unbecome_root();
if (ret != GSS_S_COMPLETE) {
ADS_STATUS adss = ADS_ERROR_GSS(ret, min);
DEBUG(10,("get_srv_gss_creds: gss_acquire_cred failed with %s\n",
ads_errstr(adss)));
status = map_nt_error_from_gss(ret, min);
}
SAFE_FREE(host_princ_s);
gss_release_name(&min, &srv_name);
return status;
}
/******************************************************************************
Create a gss state.
Try and get the cifs/server@realm principal first, then fall back to
host/server@realm.
******************************************************************************/
static NTSTATUS make_auth_gss(struct smb_srv_trans_enc_ctx *ec)
{
NTSTATUS status;
gss_cred_id_t srv_cred;
fstring fqdn;
name_to_fqdn(fqdn, global_myname());
strlower_m(fqdn);
status = get_srv_gss_creds("cifs", fqdn, GSS_C_ACCEPT, &srv_cred);
if (!NT_STATUS_IS_OK(status)) {
status = get_srv_gss_creds("host", fqdn, GSS_C_ACCEPT, &srv_cred);
if (!NT_STATUS_IS_OK(status)) {
return nt_status_squash(status);
}
}
ec->es->s.gss_state = SMB_MALLOC_P(struct smb_tran_enc_state_gss);
if (!ec->es->s.gss_state) {
OM_uint32 min;
gss_release_cred(&min, &srv_cred);
return NT_STATUS_NO_MEMORY;
}
ZERO_STRUCTP(ec->es->s.gss_state);
ec->es->s.gss_state->creds = srv_cred;
/* No context yet. */
ec->es->s.gss_state->gss_ctx = GSS_C_NO_CONTEXT;
return NT_STATUS_OK;
}
#endif
/******************************************************************************
Shutdown a server encryption context.
******************************************************************************/
static void srv_free_encryption_context(struct smb_srv_trans_enc_ctx **pp_ec)
{
struct smb_srv_trans_enc_ctx *ec = *pp_ec;
if (!ec) {
return;
}
if (ec->es) {
switch (ec->es->smb_enc_type) {
case SMB_TRANS_ENC_NTLM:
destroy_auth_ntlmssp(ec);
break;
#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
case SMB_TRANS_ENC_GSS:
break;
#endif
}
common_free_encryption_state(&ec->es);
}
SAFE_FREE(ec);
*pp_ec = NULL;
}
/******************************************************************************
Create a server encryption context.
******************************************************************************/
static NTSTATUS make_srv_encryption_context(enum smb_trans_enc_type smb_enc_type, struct smb_srv_trans_enc_ctx **pp_ec)
{
struct smb_srv_trans_enc_ctx *ec;
*pp_ec = NULL;
ec = SMB_MALLOC_P(struct smb_srv_trans_enc_ctx);
if (!ec) {
return NT_STATUS_NO_MEMORY;
}
ZERO_STRUCTP(partial_srv_trans_enc_ctx);
ec->es = SMB_MALLOC_P(struct smb_trans_enc_state);
if (!ec->es) {
SAFE_FREE(ec);
return NT_STATUS_NO_MEMORY;
}
ZERO_STRUCTP(ec->es);
ec->es->smb_enc_type = smb_enc_type;
switch (smb_enc_type) {
case SMB_TRANS_ENC_NTLM:
{
NTSTATUS status = make_auth_ntlmssp(ec);
if (!NT_STATUS_IS_OK(status)) {
srv_free_encryption_context(&ec);
return status;
}
}
break;
#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
case SMB_TRANS_ENC_GSS:
/* Acquire our credentials by calling gss_acquire_cred here. */
{
NTSTATUS status = make_auth_gss(ec);
if (!NT_STATUS_IS_OK(status)) {
srv_free_encryption_context(&ec);
return status;
}
}
break;
#endif
default:
srv_free_encryption_context(&ec);
return NT_STATUS_INVALID_PARAMETER;
}
*pp_ec = ec;
return NT_STATUS_OK;
}
/******************************************************************************
Free an encryption-allocated buffer.
******************************************************************************/
void srv_free_enc_buffer(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->es, buf);
}
}
/******************************************************************************
Decrypt an incoming buffer.
******************************************************************************/
NTSTATUS srv_decrypt_buffer(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->es, buf);
}
return NT_STATUS_OK;
}
/******************************************************************************
Encrypt an outgoing buffer. Return the encrypted pointer in buf_out.
******************************************************************************/
NTSTATUS srv_encrypt_buffer(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->es, 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.
******************************************************************************/
#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
static NTSTATUS srv_enc_spnego_gss_negotiate(unsigned char **ppdata, size_t *p_data_size, DATA_BLOB secblob)
{
OM_uint32 ret;
OM_uint32 min;
OM_uint32 flags = 0;
gss_buffer_desc in_buf, out_buf;
struct smb_tran_enc_state_gss *gss_state;
DATA_BLOB auth_reply = data_blob_null;
DATA_BLOB response = data_blob_null;
NTSTATUS status;
if (!partial_srv_trans_enc_ctx) {
status = make_srv_encryption_context(SMB_TRANS_ENC_GSS, &partial_srv_trans_enc_ctx);
if (!NT_STATUS_IS_OK(status)) {
return status;
}
}
gss_state = partial_srv_trans_enc_ctx->es->s.gss_state;
in_buf.value = secblob.data;
in_buf.length = secblob.length;
out_buf.value = NULL;
out_buf.length = 0;
become_root();
ret = gss_accept_sec_context(&min,
&gss_state->gss_ctx,
gss_state->creds,
&in_buf,
GSS_C_NO_CHANNEL_BINDINGS,
NULL,
NULL, /* Ignore oids. */
&out_buf, /* To return. */
&flags,
NULL, /* Ingore time. */
NULL); /* Ignore delegated creds. */
unbecome_root();
status = gss_err_to_ntstatus(ret, min);
if (ret != GSS_S_COMPLETE && ret != GSS_S_CONTINUE_NEEDED) {
return status;
}
/* Ensure we've got sign+seal available. */
if (ret == GSS_S_COMPLETE) {
if ((flags & (GSS_C_INTEG_FLAG|GSS_C_CONF_FLAG|GSS_C_REPLAY_FLAG|GSS_C_SEQUENCE_FLAG)) !=
(GSS_C_INTEG_FLAG|GSS_C_CONF_FLAG|GSS_C_REPLAY_FLAG|GSS_C_SEQUENCE_FLAG)) {
DEBUG(0,("srv_enc_spnego_gss_negotiate: quality of service not good enough "
"for SMB sealing.\n"));
gss_release_buffer(&min, &out_buf);
return NT_STATUS_ACCESS_DENIED;
}
}
auth_reply = data_blob(out_buf.value, out_buf.length);
gss_release_buffer(&min, &out_buf);
/* Wrap in SPNEGO. */
response = spnego_gen_auth_response(talloc_tos(), &auth_reply, status, OID_KERBEROS5);
data_blob_free(&auth_reply);
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;
}
#endif
/******************************************************************************
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(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(SMB_TRANS_ENC_NTLM, &partial_srv_trans_enc_ctx);
if (!NT_STATUS_IS_OK(status)) {
return status;
}
status = auth_ntlmssp_update(partial_srv_trans_enc_ctx->auth_ntlmssp_state, 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);
#if defined(HAVE_GSSAPI) && defined(HAVE_KRB5)
status = srv_enc_spnego_gss_negotiate(ppdata, p_data_size, secblob);
#else
/* Currently we don't SPNEGO negotiate
* back to NTLMSSP as we do in sessionsetupX. We should... */
return NT_STATUS_LOGON_FAILURE;
#endif
} else {
status = srv_enc_ntlm_negotiate(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->es->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_srv_trans_enc_ctx *ec = partial_srv_trans_enc_ctx;
/* We must have a partial context here. */
if (!ec || !ec->es || ec->auth_ntlmssp_state == NULL || ec->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 = auth_ntlmssp_update(ec->auth_ntlmssp_state, 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,ec->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_srv_trans_enc_ctx *ec;
if (!partial_srv_trans_enc_ctx) {
/* This is the initial step. */
status = srv_enc_ntlm_negotiate(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;
}
ec = partial_srv_trans_enc_ctx;
if (!ec || !ec->es || ec->auth_ntlmssp_state == NULL || ec->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 = auth_ntlmssp_update(partial_srv_trans_enc_ctx->auth_ntlmssp_state, 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,ec->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_srv_trans_enc_ctx *ec)
{
if (!ec || !ec->es) {
return NT_STATUS_LOGON_FAILURE;
}
if (ec->es->smb_enc_type == SMB_TRANS_ENC_NTLM) {
if (!auth_ntlmssp_negotiated_sign((ec->auth_ntlmssp_state))) {
return NT_STATUS_INVALID_PARAMETER;
}
if (!auth_ntlmssp_negotiated_seal((ec->auth_ntlmssp_state))) {
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->es->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(void)
{
srv_free_encryption_context(&partial_srv_trans_enc_ctx);
srv_free_encryption_context(&srv_trans_enc_ctx);
}