/* this performs a SASL/gssapi bind
we avoid using cyrus-sasl to make Samba more robust. cyrus-sasl
is very dependent on correctly configured DNS whereas
this routine is much less fragile
see RFC2078 and RFC2222 for details
*/
static ADS_STATUS ads_sasl_gssapi_do_bind(ADS_STRUCT *ads, const gss_name_t serv_name)
{
uint32_t minor_status;
gss_cred_id_t gss_cred = GSS_C_NO_CREDENTIAL;
gss_ctx_id_t context_handle = GSS_C_NO_CONTEXT;
gss_OID mech_type = GSS_C_NULL_OID;
gss_buffer_desc output_token, input_token;
uint32_t req_flags, ret_flags;
int conf_state;
struct berval cred;
struct berval *scred = NULL;
int i=0;
int gss_rc, rc;
uint8_t *p;
uint32_t max_msg_size = ADS_SASL_WRAPPING_OUT_MAX_WRAPPED;
uint8_t wrap_type = ADS_SASLWRAP_TYPE_PLAIN;
ADS_STATUS status;
struct ads_saslwrap *wrap = &ads->ldap_wrap_data;
input_token.value = NULL;
input_token.length = 0;
status = ads_init_gssapi_cred(ads, &gss_cred);
if (!ADS_ERR_OK(status)) {
goto failed;
}
/*
* Note: here we always ask the gssapi for sign and seal
* as this is negotiated later after the mutal
* authentication
*/
req_flags = GSS_C_MUTUAL_FLAG | GSS_C_REPLAY_FLAG | GSS_C_INTEG_FLAG | GSS_C_CONF_FLAG;
for (i=0; i < MAX_GSS_PASSES; i++) {
gss_rc = gss_init_sec_context(&minor_status,
gss_cred,
&context_handle,
serv_name,
mech_type,
req_flags,
0,
NULL,
&input_token,
NULL,
&output_token,
&ret_flags,
NULL);
if (scred) {
ber_bvfree(scred);
scred = NULL;
}
if (gss_rc && gss_rc != GSS_S_CONTINUE_NEEDED) {
status = ADS_ERROR_GSS(gss_rc, minor_status);
goto failed;
}
cred.bv_val = (char *)output_token.value;
cred.bv_len = output_token.length;
rc = ldap_sasl_bind_s(ads->ldap.ld, NULL, "GSSAPI", &cred, NULL, NULL,
&scred);
if (rc != LDAP_SASL_BIND_IN_PROGRESS) {
status = ADS_ERROR(rc);
goto failed;
}
if (output_token.value) {
gss_release_buffer(&minor_status, &output_token);
}
if (scred) {
input_token.value = scred->bv_val;
input_token.length = scred->bv_len;
} else {
input_token.value = NULL;
input_token.length = 0;
}
if (gss_rc == 0) break;
}
gss_rc = gss_unwrap(&minor_status,context_handle,&input_token,&output_token,
&conf_state,NULL);
if (scred) {
ber_bvfree(scred);
scred = NULL;
}
if (gss_rc) {
status = ADS_ERROR_GSS(gss_rc, minor_status);
goto failed;
}
p = (uint8_t *)output_token.value;
#if 0
file_save("sasl_gssapi.dat", output_token.value, output_token.length);
#endif
if (p) {
wrap_type = CVAL(p,0);
SCVAL(p,0,0);
max_msg_size = RIVAL(p,0);
}
gss_release_buffer(&minor_status, &output_token);
if (!(wrap_type & wrap->wrap_type)) {
/*
* the server doesn't supports the wrap
* type we want :-(
*/
DEBUG(0,("The ldap sasl wrap type doesn't match wanted[%d] server[%d]\n",
wrap->wrap_type, wrap_type));
DEBUGADD(0,("You may want to set the 'client ldap sasl wrapping' option\n"));
status = ADS_ERROR_NT(NT_STATUS_NOT_SUPPORTED);
goto failed;
}
/* 0x58 is the minimum windows accepts */
if (max_msg_size < 0x58) {
max_msg_size = 0x58;
}
output_token.length = 4;
output_token.value = SMB_MALLOC(output_token.length);
if (!output_token.value) {
output_token.length = 0;
status = ADS_ERROR_NT(NT_STATUS_NO_MEMORY);
goto failed;
}
p = (uint8_t *)output_token.value;
RSIVAL(p,0,max_msg_size);
SCVAL(p,0,wrap->wrap_type);
/*
* we used to add sprintf("dn:%s", ads->config.bind_path) here.
* but using ads->config.bind_path is the wrong! It should be
* the DN of the user object!
*
* w2k3 gives an error when we send an incorrect DN, but sending nothing
* is ok and matches the information flow used in GSS-SPNEGO.
*/
gss_rc = gss_wrap(&minor_status, context_handle,0,GSS_C_QOP_DEFAULT,
&output_token, /* used as *input* here. */
&conf_state,
&input_token); /* Used as *output* here. */
if (gss_rc) {
status = ADS_ERROR_GSS(gss_rc, minor_status);
output_token.length = 0;
SAFE_FREE(output_token.value);
goto failed;
}
/* We've finished with output_token. */
SAFE_FREE(output_token.value);
output_token.length = 0;
cred.bv_val = (char *)input_token.value;
cred.bv_len = input_token.length;
rc = ldap_sasl_bind_s(ads->ldap.ld, NULL, "GSSAPI", &cred, NULL, NULL,
&scred);
gss_release_buffer(&minor_status, &input_token);
status = ADS_ERROR(rc);
if (!ADS_ERR_OK(status)) {
goto failed;
}
if (wrap->wrap_type > ADS_SASLWRAP_TYPE_PLAIN) {
gss_rc = gss_wrap_size_limit(&minor_status, context_handle,
(wrap->wrap_type == ADS_SASLWRAP_TYPE_SEAL),
GSS_C_QOP_DEFAULT,
max_msg_size, &wrap->out.max_unwrapped);
if (gss_rc) {
status = ADS_ERROR_GSS(gss_rc, minor_status);
goto failed;
}
wrap->out.sig_size = max_msg_size - wrap->out.max_unwrapped;
wrap->in.min_wrapped = 0x2C; /* taken from a capture with LDAP unbind */
wrap->in.max_wrapped = ADS_SASL_WRAPPING_IN_MAX_WRAPPED;
status = ads_setup_sasl_wrapping(wrap->wrap_private_data, ads->ldap.ld,
&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;
}
failed:
if (gss_cred != GSS_C_NO_CREDENTIAL)
gss_release_cred(&minor_status, &gss_cred);
if (context_handle != GSS_C_NO_CONTEXT)
gss_delete_sec_context(&minor_status, &context_handle, GSS_C_NO_BUFFER);
if(scred)
ber_bvfree(scred);
return status;
}
/*
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_cred_id_t gss_cred = GSS_C_NO_CREDENTIAL;
gss_OID_desc krb5_mech_type =
{9, discard_const_p(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;
status = ads_init_gssapi_cred(ads, &gss_cred);
if (!ADS_ERR_OK(status)) {
goto failed;
}
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_cred,
&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 = spnego_gen_negTokenInit(talloc_tos(),
spnego_mechs, &unwrapped, NULL);
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(talloc_tos(), 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_cred,
&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 (gss_cred != GSS_C_NO_CREDENTIAL)
gss_release_cred(&minor_status, &gss_cred);
if (context_handle != GSS_C_NO_CONTEXT)
gss_delete_sec_context(&minor_status, &context_handle, GSS_C_NO_BUFFER);
return status;
}
