/*
generate a SPNEGO negTokenTarg packet, ready for a EXTENDED_SECURITY
kerberos session setup
*/
int spnego_gen_negTokenTarg(const char *principal, int time_offset,
DATA_BLOB *targ,
DATA_BLOB *session_key_krb5)
{
int retval;
DATA_BLOB tkt, tkt_wrapped;
const char *krb_mechs[] = {OID_KERBEROS5_OLD, OID_NTLMSSP, NULL};
/* get a kerberos ticket for the service and extract the session key */
retval = cli_krb5_get_ticket(principal, time_offset, &tkt, session_key_krb5);
if (retval)
return retval;
/* wrap that up in a nice GSS-API wrapping */
tkt_wrapped = spnego_gen_krb5_wrap(tkt, TOK_ID_KRB_AP_REQ);
/* and wrap that in a shiny SPNEGO wrapper */
*targ = gen_negTokenTarg(krb_mechs, tkt_wrapped);
data_blob_free(&tkt_wrapped);
data_blob_free(&tkt);
return retval;
}
/*
perform a LDAP/SASL/SPNEGO/GSSKRB5 bind
*/
static ADS_STATUS ads_sasl_spnego_gsskrb5_bind(ADS_STRUCT *ads, const gss_name_t serv_name)
{
ADS_STATUS status;
bool ok;
uint32 minor_status;
int gss_rc, rc;
gss_OID_desc krb5_mech_type =
{9, CONST_DISCARD(char *, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02") };
gss_OID mech_type = &krb5_mech_type;
gss_OID actual_mech_type = GSS_C_NULL_OID;
const char *spnego_mechs[] = {OID_KERBEROS5_OLD, OID_KERBEROS5, OID_NTLMSSP, NULL};
gss_ctx_id_t context_handle = GSS_C_NO_CONTEXT;
gss_buffer_desc input_token, output_token;
uint32 req_flags, ret_flags;
uint32 req_tmp, ret_tmp;
DATA_BLOB unwrapped;
DATA_BLOB wrapped;
struct berval cred, *scred = NULL;
input_token.value = NULL;
input_token.length = 0;
req_flags = GSS_C_MUTUAL_FLAG | GSS_C_REPLAY_FLAG;
switch (ads->ldap.wrap_type) {
case ADS_SASLWRAP_TYPE_SEAL:
req_flags |= GSS_C_INTEG_FLAG | GSS_C_CONF_FLAG;
break;
case ADS_SASLWRAP_TYPE_SIGN:
req_flags |= GSS_C_INTEG_FLAG;
break;
case ADS_SASLWRAP_TYPE_PLAIN:
break;
}
/* Note: here we explicit ask for the krb5 mech_type */
gss_rc = gss_init_sec_context(&minor_status,
GSS_C_NO_CREDENTIAL,
&context_handle,
serv_name,
mech_type,
req_flags,
0,
NULL,
&input_token,
&actual_mech_type,
&output_token,
&ret_flags,
NULL);
if (gss_rc && gss_rc != GSS_S_CONTINUE_NEEDED) {
status = ADS_ERROR_GSS(gss_rc, minor_status);
goto failed;
}
/*
* As some gssapi krb5 mech implementations
* automaticly add GSS_C_INTEG_FLAG and GSS_C_CONF_FLAG
* to req_flags internaly, it's not possible to
* use plain or signing only connection via
* the gssapi interface.
*
* Because of this we need to check it the ret_flags
* has more flags as req_flags and correct the value
* of ads->ldap.wrap_type.
*
* I ads->auth.flags has ADS_AUTH_SASL_FORCE
* we need to give an error.
*/
req_tmp = req_flags & (GSS_C_INTEG_FLAG | GSS_C_CONF_FLAG);
ret_tmp = ret_flags & (GSS_C_INTEG_FLAG | GSS_C_CONF_FLAG);
if (req_tmp == ret_tmp) {
/* everythings fine... */
} else if (req_flags & GSS_C_CONF_FLAG) {
/*
* here we wanted sealing but didn't got it
* from the gssapi library
*/
status = ADS_ERROR_NT(NT_STATUS_NOT_SUPPORTED);
goto failed;
} else if ((req_flags & GSS_C_INTEG_FLAG) &&
!(ret_flags & GSS_C_INTEG_FLAG)) {
/*
* here we wanted siging but didn't got it
* from the gssapi library
*/
status = ADS_ERROR_NT(NT_STATUS_NOT_SUPPORTED);
goto failed;
} else if (ret_flags & GSS_C_CONF_FLAG) {
/*
* here we didn't want sealing
* but the gssapi library forces it
* so correct the needed wrap_type if
* the caller didn't forced siging only
*/
if (ads->auth.flags & ADS_AUTH_SASL_FORCE) {
status = ADS_ERROR_NT(NT_STATUS_NOT_SUPPORTED);
goto failed;
}
ads->ldap.wrap_type = ADS_SASLWRAP_TYPE_SEAL;
req_flags = ret_flags;
} else if (ret_flags & GSS_C_INTEG_FLAG) {
/*
* here we didn't want signing
* but the gssapi library forces it
* so correct the needed wrap_type if
* the caller didn't forced plain
*/
if (ads->auth.flags & ADS_AUTH_SASL_FORCE) {
status = ADS_ERROR_NT(NT_STATUS_NOT_SUPPORTED);
goto failed;
}
ads->ldap.wrap_type = ADS_SASLWRAP_TYPE_SIGN;
req_flags = ret_flags;
} else {
/*
* This could (should?) not happen
*/
status = ADS_ERROR_NT(NT_STATUS_INTERNAL_ERROR);
goto failed;
}
/* and wrap that in a shiny SPNEGO wrapper */
unwrapped = data_blob_const(output_token.value, output_token.length);
wrapped = gen_negTokenTarg(spnego_mechs, unwrapped);
gss_release_buffer(&minor_status, &output_token);
if (unwrapped.length > wrapped.length) {
status = ADS_ERROR_NT(NT_STATUS_NO_MEMORY);
goto failed;
}
cred.bv_val = (char *)wrapped.data;
cred.bv_len = wrapped.length;
rc = ldap_sasl_bind_s(ads->ldap.ld, NULL, "GSS-SPNEGO", &cred, NULL, NULL,
&scred);
data_blob_free(&wrapped);
if (rc != LDAP_SUCCESS) {
status = ADS_ERROR(rc);
goto failed;
}
if (scred) {
wrapped = data_blob_const(scred->bv_val, scred->bv_len);
} else {
wrapped = data_blob_null;
}
ok = spnego_parse_auth_response(wrapped, NT_STATUS_OK,
OID_KERBEROS5_OLD,
&unwrapped);
if (scred) ber_bvfree(scred);
if (!ok) {
status = ADS_ERROR_NT(NT_STATUS_INVALID_NETWORK_RESPONSE);
goto failed;
}
input_token.value = unwrapped.data;
input_token.length = unwrapped.length;
/*
* As we asked for mutal authentication
* we need to pass the servers response
* to gssapi
*/
gss_rc = gss_init_sec_context(&minor_status,
GSS_C_NO_CREDENTIAL,
&context_handle,
serv_name,
mech_type,
req_flags,
0,
NULL,
&input_token,
&actual_mech_type,
&output_token,
&ret_flags,
NULL);
data_blob_free(&unwrapped);
if (gss_rc) {
status = ADS_ERROR_GSS(gss_rc, minor_status);
goto failed;
}
gss_release_buffer(&minor_status, &output_token);
/*
* If we the sign and seal options
* doesn't match after getting the response
* from the server, we don't want to use the connection
*/
req_tmp = req_flags & (GSS_C_INTEG_FLAG | GSS_C_CONF_FLAG);
ret_tmp = ret_flags & (GSS_C_INTEG_FLAG | GSS_C_CONF_FLAG);
if (req_tmp != ret_tmp) {
/* everythings fine... */
status = ADS_ERROR_NT(NT_STATUS_INVALID_NETWORK_RESPONSE);
goto failed;
}
if (ads->ldap.wrap_type > ADS_SASLWRAP_TYPE_PLAIN) {
uint32 max_msg_size = ADS_SASL_WRAPPING_OUT_MAX_WRAPPED;
gss_rc = gss_wrap_size_limit(&minor_status, context_handle,
(ads->ldap.wrap_type == ADS_SASLWRAP_TYPE_SEAL),
GSS_C_QOP_DEFAULT,
max_msg_size, &ads->ldap.out.max_unwrapped);
if (gss_rc) {
status = ADS_ERROR_GSS(gss_rc, minor_status);
goto failed;
}
ads->ldap.out.sig_size = max_msg_size - ads->ldap.out.max_unwrapped;
ads->ldap.in.min_wrapped = 0x2C; /* taken from a capture with LDAP unbind */
ads->ldap.in.max_wrapped = max_msg_size;
status = ads_setup_sasl_wrapping(ads, &ads_sasl_gssapi_ops, context_handle);
if (!ADS_ERR_OK(status)) {
DEBUG(0, ("ads_setup_sasl_wrapping() failed: %s\n",
ads_errstr(status)));
goto failed;
}
/* make sure we don't free context_handle */
context_handle = GSS_C_NO_CONTEXT;
}
status = ADS_SUCCESS;
failed:
if (context_handle != GSS_C_NO_CONTEXT)
gss_delete_sec_context(&minor_status, &context_handle, GSS_C_NO_BUFFER);
return status;
}