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/*
Unix SMB/Netbios implementation.
Version 3.0
simple kerberos5/SPNEGO routines
Copyright (C) Andrew Tridgell 2001
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 principle name string
*/
DATA_BLOB spnego_gen_negTokenInit(uint8 guid[16],
const char *OIDs[],
const char *principle)
{
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,principle);
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;
}
/*
parse a negTokenInit packet giving a GUID, a list of supported
OIDs (the mechanisms) and a principle name string
*/
BOOL spnego_parse_negTokenInit(DATA_BLOB blob,
uint8 guid[16],
char *OIDs[ASN1_MAX_OIDS],
char **principle)
{
int i;
BOOL ret;
ASN1_DATA data;
asn1_load(&data, blob);
asn1_read(&data, guid, 16);
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,principle);
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
*/
static DATA_BLOB spnego_gen_krb5_wrap(DATA_BLOB ticket)
{
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_BOOLEAN(&data, 0);
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)
{
BOOL ret;
ASN1_DATA data;
asn1_load(&data, blob);
asn1_start_tag(&data, ASN1_APPLICATION(0));
asn1_check_OID(&data, OID_KERBEROS5);
asn1_check_BOOLEAN(&data, 0);
*ticket = data_blob(data.data, asn1_tag_remaining(&data));
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(struct cli_state *cli, char *principle)
{
char *p;
fstring service;
char *realm;
DATA_BLOB tkt, tkt_wrapped, targ;
const char *krb_mechs[] = {OID_KERBEROS5_OLD, OID_NTLMSSP, NULL};
fstrcpy(service, principle);
p = strchr_m(service, '@');
if (!p) {
DEBUG(1,("Malformed principle [%s] in spnego_gen_negTokenTarg\n",
principle));
return data_blob(NULL, 0);
}
*p = 0;
realm = p+1;
/* get a kerberos ticket for the service */
tkt = krb5_get_ticket(service, realm);
/* wrap that up in a nice GSS-API wrapping */
tkt_wrapped = spnego_gen_krb5_wrap(tkt);
/* 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(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 NTLMSSP challenge packet given two security blobs
The second challenge is optional
*/
BOOL spnego_gen_challenge(DATA_BLOB *blob,
DATA_BLOB *chal1, DATA_BLOB *chal2)
{
ASN1_DATA data;
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,1);
asn1_pop_tag(&data);
asn1_push_tag(&data,ASN1_CONTEXT(1));
asn1_write_OID(&data, OID_NTLMSSP);
asn1_pop_tag(&data);
asn1_push_tag(&data,ASN1_CONTEXT(2));
asn1_write_OctetString(&data, chal1->data, chal1->length);
asn1_pop_tag(&data);
/* the second challenge is optional (XP doesn't send it) */
if (chal2) {
asn1_push_tag(&data,ASN1_CONTEXT(3));
asn1_write_OctetString(&data, chal2->data, chal2->length);
asn1_pop_tag(&data);
}
asn1_pop_tag(&data);
asn1_pop_tag(&data);
if (data.has_error) {
return False;
}
*blob = data_blob(data.data, data.length);
asn1_free(&data);
return True;
}
/*
generate a SPNEGO NTLMSSP 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 NTLMSSP 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;
}
/*
this is a tiny msrpc packet generator. I am only using this to
avoid tying this code to a particular varient of our rpc code. This
generator is not general enough for all our rpc needs, its just
enough for the spnego/ntlmssp code
format specifiers are:
U = unicode string (input is unix string)
B = data blob (pointer + length)
b = data blob in header (pointer + length)
d = word (4 bytes)
C = constant ascii string
*/
BOOL msrpc_gen(DATA_BLOB *blob,
const char *format, ...)
{
int i, n;
va_list ap;
char *s;
uint8 *b;
int head_size=0, data_size=0;
int head_ofs, data_ofs;
/* first scan the format to work out the header and body size */
va_start(ap, format);
for (i=0; format[i]; i++) {
switch (format[i]) {
case 'U':
s = va_arg(ap, char *);
head_size += 8;
data_size += str_charnum(s) * 2;
break;
case 'B':
b = va_arg(ap, uint8 *);
head_size += 8;
data_size += va_arg(ap, int);
break;
case 'b':
b = va_arg(ap, uint8 *);
head_size += va_arg(ap, int);
break;
case 'd':
n = va_arg(ap, int);
head_size += 4;
break;
case 'C':
s = va_arg(ap, char *);
head_size += str_charnum(s) + 1;
break;
}
}
va_end(ap);
/* allocate the space, then scan the format again to fill in the values */
blob->data = malloc(head_size + data_size);
blob->length = head_size + data_size;
if (!blob->data) return False;
head_ofs = 0;
data_ofs = head_size;
va_start(ap, format);
for (i=0; format[i]; i++) {
switch (format[i]) {
case 'U':
s = va_arg(ap, char *);
n = str_charnum(s);
SSVAL(blob->data, head_ofs, n*2); head_ofs += 2;
SSVAL(blob->data, head_ofs, n*2); head_ofs += 2;
SIVAL(blob->data, head_ofs, data_ofs); head_ofs += 4;
push_string(NULL, blob->data+data_ofs, s, n*2, STR_UNICODE|STR_NOALIGN);
data_ofs += n*2;
break;
case 'B':
b = va_arg(ap, uint8 *);
n = va_arg(ap, int);
SSVAL(blob->data, head_ofs, n); head_ofs += 2;
SSVAL(blob->data, head_ofs, n); head_ofs += 2;
SIVAL(blob->data, head_ofs, data_ofs); head_ofs += 4;
memcpy(blob->data+data_ofs, b, n);
data_ofs += n;
break;
case 'd':
n = va_arg(ap, int);
SIVAL(blob->data, head_ofs, n); head_ofs += 4;
break;
case 'b':
b = va_arg(ap, uint8 *);
n = va_arg(ap, int);
memcpy(blob->data + head_ofs, b, n);
head_ofs += n;
break;
case 'C':
s = va_arg(ap, char *);
head_ofs += push_string(NULL, blob->data+head_ofs, s, -1,
STR_ASCII|STR_TERMINATE);
break;
}
}
va_end(ap);
return True;
}
/*
this is a tiny msrpc packet parser. This the the partner of msrpc_gen
format specifiers are:
U = unicode string (input is unix string)
B = data blob
b = data blob in header
d = word (4 bytes)
C = constant ascii string
*/
BOOL msrpc_parse(DATA_BLOB *blob,
const char *format, ...)
{
int i;
va_list ap;
char **ps, *s;
DATA_BLOB *b;
int head_ofs = 0;
uint16 len1, len2;
uint32 ptr;
uint32 *v;
pstring p;
va_start(ap, format);
for (i=0; format[i]; i++) {
switch (format[i]) {
case 'U':
len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
ptr = IVAL(blob->data, head_ofs); head_ofs += 4;
/* make sure its in the right format - be strict */
if (len1 != len2 || (len1&1) || ptr + len1 > blob->length) {
return False;
}
ps = va_arg(ap, char **);
pull_string(NULL, p, blob->data + ptr, -1, len1,
STR_UNICODE|STR_NOALIGN);
(*ps) = strdup(p);
break;
case 'B':
len1 = SVAL(blob->data, head_ofs); head_ofs += 2;
len2 = SVAL(blob->data, head_ofs); head_ofs += 2;
ptr = IVAL(blob->data, head_ofs); head_ofs += 4;
/* make sure its in the right format - be strict */
if (len1 != len2 || ptr + len1 > blob->length) {
return False;
}
b = (DATA_BLOB *)va_arg(ap, void *);
*b = data_blob(blob->data + ptr, len1);
break;
case 'b':
b = (DATA_BLOB *)va_arg(ap, void *);
len1 = va_arg(ap, unsigned);
*b = data_blob(blob->data + head_ofs, len1);
head_ofs += len1;
break;
case 'd':
v = va_arg(ap, uint32 *);
*v = IVAL(blob->data, head_ofs); head_ofs += 4;
break;
case 'C':
s = va_arg(ap, char *);
head_ofs += pull_string(NULL, p, blob->data+head_ofs, -1,
blob->length - head_ofs,
STR_ASCII|STR_TERMINATE);
if (strcmp(s, p) != 0) {
return False;
}
break;
}
}
va_end(ap);
return True;
}
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