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samba-mirror/source/libsmb/clispnego.c
Andrew Bartlett f3bbc87b0d Changes all over the shop, but all towards:
- NTLM2 support in the server
 - KEY_EXCH support in the server
 - variable length session keys.

In detail:

 - NTLM2 is an extension of NTLMv1, that is compatible with existing
domain controllers (unlike NTLMv2, which requires a DC upgrade).

 * This is known as 'NTLMv2 session security' *

(This is not yet implemented on the RPC pipes however, so there may
well still be issues for PDC setups, particuarly around password
changes.  We do not fully understand the sign/seal implications of
NTLM2 on RPC pipes.)

This requires modifications to our authentication subsystem, as we
must handle the 'challege' input into the challenge-response algorithm
being changed.  This also needs to be turned off for
'security=server', which does not support this.

- KEY_EXCH is another 'security' mechanism, whereby the session key
actually used by the server is sent by the client, rather than being
the shared-secret directly or indirectly.

- As both these methods change the session key, the auth subsystem
needed to be changed, to 'override' session keys provided by the
backend.

- There has also been a major overhaul of the NTLMSSP subsystem, to merge the 'client' and 'server' functions, so they both operate on a single structure.  This should help the SPNEGO implementation.

- The 'names blob' in NTLMSSP is always in unicode - never in ascii.
Don't make an ascii version ever.

- The other big change is to allow variable length session keys.  We
have always assumed that session keys are 16 bytes long - and padded
to this length if shorter.  However, Kerberos session keys are 8 bytes
long, when the krb5 login uses DES.

 * This fix allows SMB signging on machines not yet running MIT KRB5 1.3.1. *

- Add better DEBUG() messages to ntlm_auth, warning administrators of
misconfigurations that prevent access to the privileged pipe.  This
should help reduce some of the 'it just doesn't work' issues.

- Fix data_blob_talloc() to behave the same way data_blob() does when
passed a NULL data pointer.  (just allocate)


REMEMBER to make clean after this commit - I have changed plenty of data structures...
-

537 lines
12 KiB
C

/*
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 2 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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "includes.h"
/*
generate a negTokenInit packet given a GUID, a list of supported
OIDs (the mechanisms) and a principal name string
*/
DATA_BLOB spnego_gen_negTokenInit(uint8 guid[16],
const char *OIDs[],
const char *principal)
{
int i;
ASN1_DATA data;
DATA_BLOB ret;
memset(&data, 0, sizeof(data));
asn1_write(&data, guid, 16);
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(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));
asn1_free(&data);
}
ret = data_blob(data.data, data.length);
asn1_free(&data);
return ret;
}
/*
Generate a negTokenInit as used by the client side ... It has a mechType
(OID), and a mechToken (a security blob) ...
Really, we need to break out the NTLMSSP stuff as well, because it could be
raw in the packets!
*/
DATA_BLOB gen_negTokenInit(const char *OID, DATA_BLOB blob)
{
ASN1_DATA data;
DATA_BLOB ret;
memset(&data, 0, sizeof(data));
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));
asn1_write_OID(&data, OID);
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 negTokenInit at offset %d\n", (int)data.ofs));
asn1_free(&data);
}
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)
{
int i;
BOOL ret;
ASN1_DATA data;
asn1_load(&data, blob);
asn1_start_tag(&data,ASN1_APPLICATION(0));
asn1_check_OID(&data,OID_SPNEGO);
asn1_start_tag(&data,ASN1_CONTEXT(0));
asn1_start_tag(&data,ASN1_SEQUENCE(0));
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; i++) {
char *oid = NULL;
asn1_read_OID(&data,&oid);
OIDs[i] = oid;
}
OIDs[i] = NULL;
asn1_end_tag(&data);
asn1_end_tag(&data);
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,principal);
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_end_tag(&data);
ret = !data.has_error;
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;
memset(&data, 0, sizeof(data));
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));
asn1_free(&data);
}
ret = data_blob(data.data, data.length);
asn1_free(&data);
return ret;
}
/*
parse a negTokenTarg packet giving a list of OIDs and a security blob
*/
BOOL parse_negTokenTarg(DATA_BLOB blob, char *OIDs[ASN1_MAX_OIDS], DATA_BLOB *secblob)
{
int i;
ASN1_DATA data;
asn1_load(&data, blob);
asn1_start_tag(&data, ASN1_APPLICATION(0));
asn1_check_OID(&data,OID_SPNEGO);
asn1_start_tag(&data, ASN1_CONTEXT(0));
asn1_start_tag(&data, ASN1_SEQUENCE(0));
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; i++) {
char *oid = NULL;
asn1_read_OID(&data,&oid);
OIDs[i] = oid;
}
OIDs[i] = NULL;
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_start_tag(&data, ASN1_CONTEXT(2));
asn1_read_OctetString(&data,secblob);
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_end_tag(&data);
if (data.has_error) {
DEBUG(1,("Failed to parse negTokenTarg at offset %d\n", (int)data.ofs));
asn1_free(&data);
return False;
}
asn1_free(&data);
return True;
}
/*
generate a krb5 GSS-API wrapper packet given a ticket
*/
DATA_BLOB spnego_gen_krb5_wrap(DATA_BLOB ticket, const uint8 tok_id[2])
{
ASN1_DATA data;
DATA_BLOB ret;
memset(&data, 0, sizeof(data));
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));
asn1_free(&data);
}
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;
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;
asn1_free(&data);
return ret;
}
/*
generate a SPNEGO negTokenTarg packet, ready for a EXTENDED_SECURITY
kerberos session setup
*/
DATA_BLOB spnego_gen_negTokenTarg(const char *principal, int time_offset, DATA_BLOB *session_key_krb5)
{
DATA_BLOB tkt, tkt_wrapped, targ;
const char *krb_mechs[] = {OID_KERBEROS5_OLD, OID_NTLMSSP, NULL};
/* get a kerberos ticket for the service and extract the session key */
tkt = cli_krb5_get_ticket(principal, time_offset, session_key_krb5);
if (tkt.data == NULL)
return tkt;
/* 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 targ;
}
/*
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);
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, 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, chal2);
asn1_end_tag(&data);
}
asn1_end_tag(&data);
asn1_end_tag(&data);
ret = !data.has_error;
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;
memset(&data, 0, sizeof(data));
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)
{
ASN1_DATA data;
asn1_load(&data, blob);
asn1_start_tag(&data, ASN1_CONTEXT(1));
asn1_start_tag(&data, ASN1_SEQUENCE(0));
asn1_start_tag(&data, ASN1_CONTEXT(2));
asn1_read_OctetString(&data,auth);
asn1_end_tag(&data);
asn1_end_tag(&data);
asn1_end_tag(&data);
if (data.has_error) {
DEBUG(3,("spnego_parse_auth failed at %d\n", (int)data.ofs));
asn1_free(&data);
return False;
}
asn1_free(&data);
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_NEG_RESULT_ACCEPT;
} else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
negResult = SPNEGO_NEG_RESULT_INCOMPLETE;
} else {
negResult = SPNEGO_NEG_RESULT_REJECT;
}
ZERO_STRUCT(data);
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 (reply->data != NULL) {
asn1_push_tag(&data,ASN1_CONTEXT(1));
asn1_write_OID(&data, mechOID);
asn1_pop_tag(&data);
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 NTLMSSP auth packet. This contains the encrypted passwords
*/
BOOL spnego_parse_auth_response(DATA_BLOB blob, NTSTATUS nt_status,
DATA_BLOB *auth)
{
ASN1_DATA data;
uint8 negResult;
if (NT_STATUS_IS_OK(nt_status)) {
negResult = SPNEGO_NEG_RESULT_ACCEPT;
} else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
negResult = SPNEGO_NEG_RESULT_INCOMPLETE;
} else {
negResult = SPNEGO_NEG_RESULT_REJECT;
}
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);
if (negResult == SPNEGO_NEG_RESULT_INCOMPLETE) {
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, auth);
asn1_end_tag(&data);
}
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;
}