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/*
Unix SMB/CIFS implementation.
simple kerberos5/SPNEGO routines
Copyright (C) Andrew Tridgell 2001
Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2002
Copyright (C) Luke Howard 2003
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 "../libcli/auth/spnego.h"
#include "smb_krb5.h"
/*
generate a negTokenInit packet given a list of supported
OIDs (the mechanisms) a blob, and a principal name string
*/
DATA_BLOB spnego_gen_negTokenInit(const char *OIDs[],
DATA_BLOB *psecblob,
const char *principal)
{
int i;
ASN1_DATA *data;
DATA_BLOB ret;
data = asn1_init(talloc_tos());
if (data == NULL) {
return data_blob_null;
}
asn1_push_tag(data,ASN1_APPLICATION(0));
asn1_write_OID(data,OID_SPNEGO);
asn1_push_tag(data,ASN1_CONTEXT(0));
asn1_push_tag(data,ASN1_SEQUENCE(0));
asn1_push_tag(data,ASN1_CONTEXT(0));
asn1_push_tag(data,ASN1_SEQUENCE(0));
for (i=0; OIDs[i]; i++) {
asn1_write_OID(data,OIDs[i]);
}
asn1_pop_tag(data);
asn1_pop_tag(data);
if (psecblob && psecblob->length && psecblob->data) {
asn1_push_tag(data, ASN1_CONTEXT(2));
asn1_write_OctetString(data,psecblob->data,
psecblob->length);
asn1_pop_tag(data);
}
if (principal) {
asn1_push_tag(data, ASN1_CONTEXT(3));
asn1_push_tag(data, ASN1_SEQUENCE(0));
asn1_push_tag(data, ASN1_CONTEXT(0));
asn1_write_GeneralString(data,principal);
asn1_pop_tag(data);
asn1_pop_tag(data);
asn1_pop_tag(data);
}
asn1_pop_tag(data);
asn1_pop_tag(data);
asn1_pop_tag(data);
if (data->has_error) {
DEBUG(1,("Failed to build negTokenInit at offset %d\n", (int)data->ofs));
}
ret = data_blob(data->data, data->length);
asn1_free(data);
return ret;
}
/*
parse a negTokenInit packet giving a GUID, a list of supported
OIDs (the mechanisms) and a principal name string
*/
bool spnego_parse_negTokenInit(DATA_BLOB blob,
char *OIDs[ASN1_MAX_OIDS],
char **principal,
DATA_BLOB *secblob)
{
int i;
bool ret;
ASN1_DATA *data;
data = asn1_init(talloc_tos());
if (data == NULL) {
return false;
}
asn1_load(data, blob);
asn1_start_tag(data,ASN1_APPLICATION(0));
asn1_check_OID(data,OID_SPNEGO);
/* negTokenInit [0] NegTokenInit */
asn1_start_tag(data,ASN1_CONTEXT(0));
asn1_start_tag(data,ASN1_SEQUENCE(0));
/* mechTypes [0] MechTypeList OPTIONAL */
/* Not really optional, we depend on this to decide
* what mechanisms we have to work with. */
asn1_start_tag(data,ASN1_CONTEXT(0));
asn1_start_tag(data,ASN1_SEQUENCE(0));
for (i=0; asn1_tag_remaining(data) > 0 && i < ASN1_MAX_OIDS-1; i++) {
const char *oid_str = NULL;
asn1_read_OID(data,talloc_autofree_context(),&oid_str);
OIDs[i] = CONST_DISCARD(char *, oid_str);
}
OIDs[i] = NULL;
asn1_end_tag(data);
asn1_end_tag(data);
if (principal) {
*principal = NULL;
}
if (secblob) {
*secblob = data_blob_null;
}
/*
Win7 + Live Sign-in Assistant attaches a mechToken
ASN1_CONTEXT(2) to the negTokenInit packet
which breaks our negotiation if we just assume
the next tag is ASN1_CONTEXT(3).
*/
if (asn1_tag_remaining(data) > 0) {
if (asn1_peek_tag(data, ASN1_CONTEXT(1))) {
uint8 flags;
/* reqFlags [1] ContextFlags OPTIONAL */
asn1_start_tag(data, ASN1_CONTEXT(1));
asn1_start_tag(data, ASN1_BIT_STRING);
while (asn1_tag_remaining(data) > 0) {
asn1_read_uint8(data, &flags);
}
asn1_end_tag(data);
asn1_end_tag(data);
}
}
if (asn1_tag_remaining(data) > 0) {
if (asn1_peek_tag(data, ASN1_CONTEXT(2))) {
DATA_BLOB sblob = data_blob_null;
/* mechToken [2] OCTET STRING OPTIONAL */
asn1_start_tag(data, ASN1_CONTEXT(2));
asn1_read_OctetString(data, talloc_autofree_context(),
&sblob);
asn1_end_tag(data);
if (secblob) {
*secblob = sblob;
}
}
}
if (asn1_tag_remaining(data) > 0) {
if (asn1_peek_tag(data, ASN1_CONTEXT(3))) {
char *princ = NULL;
/* mechListMIC [3] OCTET STRING OPTIONAL */
asn1_start_tag(data, ASN1_CONTEXT(3));
asn1_start_tag(data, ASN1_SEQUENCE(0));
asn1_start_tag(data, ASN1_CONTEXT(0));
asn1_read_GeneralString(data,talloc_autofree_context(),
&princ);
asn1_end_tag(data);
asn1_end_tag(data);
asn1_end_tag(data);
if (principal) {
*principal = princ;
}
}
}
asn1_end_tag(data);
asn1_end_tag(data);
asn1_end_tag(data);
ret = !data->has_error;
if (data->has_error) {
int j;
if (principal) {
TALLOC_FREE(*principal);
}
if (secblob) {
data_blob_free(secblob);
}
for(j = 0; j < i && j < ASN1_MAX_OIDS-1; j++) {
TALLOC_FREE(OIDs[j]);
}
}
asn1_free(data);
return ret;
}
/*
generate a negTokenTarg packet given a list of OIDs and a security blob
*/
DATA_BLOB gen_negTokenTarg(const char *OIDs[], DATA_BLOB blob)
{
int i;
ASN1_DATA *data;
DATA_BLOB ret;
data = asn1_init(talloc_tos());
if (data == NULL) {
return data_blob_null;
}
asn1_push_tag(data, ASN1_APPLICATION(0));
asn1_write_OID(data,OID_SPNEGO);
asn1_push_tag(data, ASN1_CONTEXT(0));
asn1_push_tag(data, ASN1_SEQUENCE(0));
asn1_push_tag(data, ASN1_CONTEXT(0));
asn1_push_tag(data, ASN1_SEQUENCE(0));
for (i=0; OIDs[i]; i++) {
asn1_write_OID(data,OIDs[i]);
}
asn1_pop_tag(data);
asn1_pop_tag(data);
asn1_push_tag(data, ASN1_CONTEXT(2));
asn1_write_OctetString(data,blob.data,blob.length);
asn1_pop_tag(data);
asn1_pop_tag(data);
asn1_pop_tag(data);
asn1_pop_tag(data);
if (data->has_error) {
DEBUG(1,("Failed to build negTokenTarg at offset %d\n", (int)data->ofs));
}
ret = data_blob(data->data, data->length);
asn1_free(data);
return ret;
}
/*
generate a krb5 GSS-API wrapper packet given a ticket
*/
DATA_BLOB spnego_gen_krb5_wrap(const DATA_BLOB ticket, const uint8 tok_id[2])
{
ASN1_DATA *data;
DATA_BLOB ret;
data = asn1_init(talloc_tos());
if (data == NULL) {
return data_blob_null;
}
asn1_push_tag(data, ASN1_APPLICATION(0));
asn1_write_OID(data, OID_KERBEROS5);
asn1_write(data, tok_id, 2);
asn1_write(data, ticket.data, ticket.length);
asn1_pop_tag(data);
if (data->has_error) {
DEBUG(1,("Failed to build krb5 wrapper at offset %d\n", (int)data->ofs));
}
ret = data_blob(data->data, data->length);
asn1_free(data);
return ret;
}
/*
parse a krb5 GSS-API wrapper packet giving a ticket
*/
bool spnego_parse_krb5_wrap(DATA_BLOB blob, DATA_BLOB *ticket, uint8 tok_id[2])
{
bool ret;
ASN1_DATA *data;
int data_remaining;
data = asn1_init(talloc_tos());
if (data == NULL) {
return false;
}
asn1_load(data, blob);
asn1_start_tag(data, ASN1_APPLICATION(0));
asn1_check_OID(data, OID_KERBEROS5);
data_remaining = asn1_tag_remaining(data);
if (data_remaining < 3) {
data->has_error = True;
} else {
asn1_read(data, tok_id, 2);
data_remaining -= 2;
*ticket = data_blob(NULL, data_remaining);
asn1_read(data, ticket->data, ticket->length);
}
asn1_end_tag(data);
ret = !data->has_error;
if (data->has_error) {
data_blob_free(ticket);
}
asn1_free(data);
return ret;
}
/*
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, uint32 extra_ap_opts,
time_t *expire_time)
{
int retval;
DATA_BLOB tkt, tkt_wrapped;
const char *krb_mechs[] = {OID_KERBEROS5_OLD, OID_KERBEROS5, 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, extra_ap_opts, NULL,
expire_time, NULL);
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;
}
/*
parse a spnego NTLMSSP challenge packet giving two security blobs
*/
bool spnego_parse_challenge(const DATA_BLOB blob,
DATA_BLOB *chal1, DATA_BLOB *chal2)
{
bool ret;
ASN1_DATA *data;
ZERO_STRUCTP(chal1);
ZERO_STRUCTP(chal2);
data = asn1_init(talloc_tos());
if (data == NULL) {
return false;
}
asn1_load(data, blob);
asn1_start_tag(data,ASN1_CONTEXT(1));
asn1_start_tag(data,ASN1_SEQUENCE(0));
asn1_start_tag(data,ASN1_CONTEXT(0));
asn1_check_enumerated(data,1);
asn1_end_tag(data);
asn1_start_tag(data,ASN1_CONTEXT(1));
asn1_check_OID(data, OID_NTLMSSP);
asn1_end_tag(data);
asn1_start_tag(data,ASN1_CONTEXT(2));
asn1_read_OctetString(data, talloc_autofree_context(), chal1);
asn1_end_tag(data);
/* the second challenge is optional (XP doesn't send it) */
if (asn1_tag_remaining(data)) {
asn1_start_tag(data,ASN1_CONTEXT(3));
asn1_read_OctetString(data, talloc_autofree_context(), chal2);
asn1_end_tag(data);
}
asn1_end_tag(data);
asn1_end_tag(data);
ret = !data->has_error;
if (data->has_error) {
data_blob_free(chal1);
data_blob_free(chal2);
}
asn1_free(data);
return ret;
}
/*
generate a SPNEGO auth packet. This will contain the encrypted passwords
*/
DATA_BLOB spnego_gen_auth(DATA_BLOB blob)
{
ASN1_DATA *data;
DATA_BLOB ret;
data = asn1_init(talloc_tos());
if (data == NULL) {
return data_blob_null;
}
asn1_push_tag(data, ASN1_CONTEXT(1));
asn1_push_tag(data, ASN1_SEQUENCE(0));
asn1_push_tag(data, ASN1_CONTEXT(2));
asn1_write_OctetString(data,blob.data,blob.length);
asn1_pop_tag(data);
asn1_pop_tag(data);
asn1_pop_tag(data);
ret = data_blob(data->data, data->length);
asn1_free(data);
return ret;
}
/*
parse a SPNEGO auth packet. This contains the encrypted passwords
*/
bool spnego_parse_auth(DATA_BLOB blob, DATA_BLOB *auth)
{
ssize_t len;
struct spnego_data token;
len = spnego_read_data(talloc_tos(), blob, &token);
if (len == -1) {
DEBUG(3,("spnego_parse_auth: spnego_read_data failed\n"));
return false;
}
if (token.type != SPNEGO_NEG_TOKEN_TARG) {
DEBUG(3,("spnego_parse_auth: wrong token type: %d\n",
token.type));
spnego_free_data(&token);
return false;
}
*auth = data_blob_talloc(talloc_tos(),
token.negTokenTarg.responseToken.data,
token.negTokenTarg.responseToken.length);
spnego_free_data(&token);
return true;
}
/*
generate a minimal SPNEGO response packet. Doesn't contain much.
*/
DATA_BLOB spnego_gen_auth_response(DATA_BLOB *reply, NTSTATUS nt_status,
const char *mechOID)
{
ASN1_DATA *data;
DATA_BLOB ret;
uint8 negResult;
if (NT_STATUS_IS_OK(nt_status)) {
negResult = SPNEGO_ACCEPT_COMPLETED;
} else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
negResult = SPNEGO_ACCEPT_INCOMPLETE;
} else {
negResult = SPNEGO_REJECT;
}
data = asn1_init(talloc_tos());
if (data == NULL) {
return data_blob_null;
}
asn1_push_tag(data, ASN1_CONTEXT(1));
asn1_push_tag(data, ASN1_SEQUENCE(0));
asn1_push_tag(data, ASN1_CONTEXT(0));
asn1_write_enumerated(data, negResult);
asn1_pop_tag(data);
if (mechOID) {
asn1_push_tag(data,ASN1_CONTEXT(1));
asn1_write_OID(data, mechOID);
asn1_pop_tag(data);
}
if (reply && reply->data != NULL) {
asn1_push_tag(data,ASN1_CONTEXT(2));
asn1_write_OctetString(data, reply->data, reply->length);
asn1_pop_tag(data);
}
asn1_pop_tag(data);
asn1_pop_tag(data);
ret = data_blob(data->data, data->length);
asn1_free(data);
return ret;
}
/*
parse a SPNEGO auth packet. This contains the encrypted passwords
*/
bool spnego_parse_auth_response(DATA_BLOB blob, NTSTATUS nt_status,
const char *mechOID,
DATA_BLOB *auth)
{
ASN1_DATA *data;
uint8 negResult;
if (NT_STATUS_IS_OK(nt_status)) {
negResult = SPNEGO_ACCEPT_COMPLETED;
} else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
negResult = SPNEGO_ACCEPT_INCOMPLETE;
} else {
negResult = SPNEGO_REJECT;
}
data = asn1_init(talloc_tos());
if (data == NULL) {
return false;
}
asn1_load(data, blob);
asn1_start_tag(data, ASN1_CONTEXT(1));
asn1_start_tag(data, ASN1_SEQUENCE(0));
asn1_start_tag(data, ASN1_CONTEXT(0));
asn1_check_enumerated(data, negResult);
asn1_end_tag(data);
*auth = data_blob_null;
if (asn1_tag_remaining(data)) {
asn1_start_tag(data,ASN1_CONTEXT(1));
asn1_check_OID(data, mechOID);
asn1_end_tag(data);
if (asn1_tag_remaining(data)) {
asn1_start_tag(data,ASN1_CONTEXT(2));
asn1_read_OctetString(data, talloc_autofree_context(), auth);
asn1_end_tag(data);
}
} else if (negResult == SPNEGO_ACCEPT_INCOMPLETE) {
data->has_error = 1;
}
/* Binding against Win2K DC returns a duplicate of the responseToken in
* the optional mechListMIC field. This is a bug in Win2K. We ignore
* this field if it exists. Win2K8 may return a proper mechListMIC at
* which point we need to implement the integrity checking. */
if (asn1_tag_remaining(data)) {
DATA_BLOB mechList = data_blob_null;
asn1_start_tag(data, ASN1_CONTEXT(3));
asn1_read_OctetString(data, talloc_autofree_context(), &mechList);
asn1_end_tag(data);
data_blob_free(&mechList);
DEBUG(5,("spnego_parse_auth_response received mechListMIC, "
"ignoring.\n"));
}
asn1_end_tag(data);
asn1_end_tag(data);
if (data->has_error) {
DEBUG(3,("spnego_parse_auth_response failed at %d\n", (int)data->ofs));
asn1_free(data);
data_blob_free(auth);
return False;
}
asn1_free(data);
return True;
}
|