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wireshark/epan/dissectors/packet-spnego.c

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/* packet-spnego.c
* Routines for the simple and protected GSS-API negotiation mechanism
* as described in RFC 2478.
* Copyright 2002, Tim Potter <tpot@samba.org>
* Copyright 2002, Richard Sharpe <rsharpe@ns.aus.com>
* Copyright 2003, Richard Sharpe <rsharpe@richardsharpe.com>
* Copyright 2005, Ronnie Sahlberg (krb decryption)
*
* $Id$
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
* Copyright 1998 Gerald Combs
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
/* The heimdal code for decryption of GSSAPI wrappers using heimdal comes from
Heimdal 1.6 and has been modified for ethereal's requirements.
*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#include <string.h>
#include <glib.h>
#include <epan/packet.h>
#include <epan/asn1.h>
#include "format-oid.h"
#include "packet-ber.h"
#include "packet-dcerpc.h"
#include "packet-gssapi.h"
#include "packet-kerberos.h"
#include <epan/crypt-rc4.h>
#include <epan/conversation.h>
#include <epan/emem.h>
#define SPNEGO_negTokenInit 0
#define SPNEGO_negTokenTarg 1
#define SPNEGO_mechTypes 0
#define SPNEGO_reqFlags 1
#define SPNEGO_mechToken 2
#define SPNEGO_mechListMIC 3
#define SPNEGO_negResult 0
#define SPNEGO_supportedMech 1
#define SPNEGO_responseToken 2
#define SPNEGO_negResult_accept_completed 0
#define SPNEGO_negResult_accept_incomplete 1
#define SPNEGO_negResult_accept_reject 2
static int proto_spnego = -1;
static int proto_spnego_krb5 = -1;
static int hf_spnego = -1;
static int hf_spnego_mech = -1;
static int hf_spnego_this_mech = -1;
static int hf_spnego_negtokeninit = -1;
static int hf_spnego_negtokentarg = -1;
static int hf_spnego_mechtype = -1;
static int hf_spnego_mechtoken = -1;
static int hf_spnego_negtokentarg_negresult = -1;
static int hf_spnego_mechlistmic = -1;
static int hf_spnego_responsetoken = -1;
static int hf_spnego_reqflags = -1;
static int hf_spnego_wraptoken = -1;
static int hf_spnego_krb5 = -1;
static int hf_spnego_krb5_tok_id = -1;
static int hf_spnego_krb5_sgn_alg = -1;
static int hf_spnego_krb5_seal_alg = -1;
static int hf_spnego_krb5_snd_seq = -1;
static int hf_spnego_krb5_sgn_cksum = -1;
static int hf_spnego_krb5_confounder = -1;
static int hf_gssapi_reqflags_deleg = -1;
static int hf_gssapi_reqflags_mutual = -1;
static int hf_gssapi_reqflags_replay = -1;
static int hf_gssapi_reqflags_sequence = -1;
static int hf_gssapi_reqflags_anon = -1;
static int hf_gssapi_reqflags_conf = -1;
static int hf_gssapi_reqflags_integ = -1;
static gint ett_spnego = -1;
static gint ett_spnego_negtokeninit = -1;
static gint ett_spnego_negtokentarg = -1;
static gint ett_spnego_mechtype = -1;
static gint ett_spnego_mechtoken = -1;
static gint ett_spnego_mechlistmic = -1;
static gint ett_spnego_responsetoken = -1;
static gint ett_spnego_wraptoken = -1;
static gint ett_spnego_krb5 = -1;
static gint ett_spnego_reqflags = -1;
static const value_string spnego_negResult_vals[] = {
{ SPNEGO_negResult_accept_completed, "Accept Completed" },
{ SPNEGO_negResult_accept_incomplete, "Accept Incomplete" },
{ SPNEGO_negResult_accept_reject, "Accept Reject"},
{ 0, NULL}
};
/*
* These should be in the GSSAPI dissector ... XXX
*/
static const true_false_string tfs_reqflags_deleg = {
"Delegation Requested",
"Delegation NOT Requested"
};
static const true_false_string tfs_reqflags_mutual = {
"Mutual Authentication Requested",
"Mutual Authentication NOT Requested"
};
static const true_false_string tfs_reqflags_replay = {
"Replay Detection Requested",
"Replay Detection NOT Requested"
};
static const true_false_string tfs_reqflags_sequence = {
"Out-of-sequence Detection Requested",
"Out-of-sequence Detection NOT Requested"
};
static const true_false_string tfs_reqflags_anon = {
"Anonymous Authentication Requested",
"Anonymous Authentication NOT Requested"
};
static const true_false_string tfs_reqflags_conf = {
"Per-message Confidentiality Requested",
"Per-message Confidentiality NOT Requested"
};
static const true_false_string tfs_reqflags_integ = {
"Per-message Integrity Requested",
"Per-message Integrity NOT Requested"
};
/*
* This takes an OID in binary form, not an OID as a text string, as
* an argument.
*/
static gssapi_oid_value *
gssapi_lookup_oid(subid_t *oid, guint oid_len)
{
gchar *oid_key;
gchar *p;
unsigned int i;
int len;
gssapi_oid_value *value;
/*
* Convert the OID to a string, as text strings are used as
* keys in the OID hash table.
*/
oid_key = ep_alloc(oid_len * 22 + 1);
p = oid_key;
len = g_snprintf(p, oid_len * 22 + 1, "%lu", (unsigned long)oid[0]);
p += len;
for (i = 1; i < oid_len;i++) {
len = g_snprintf(p, oid_len * 22 + 1 -(p-oid_key),".%lu", (unsigned long)oid[i]);
p += len;
}
value = gssapi_lookup_oid_str(oid_key);
return value;
}
/* Display an ASN1 parse error. Taken from packet-snmp.c */
static dissector_handle_t data_handle;
static dissector_handle_t
gssapi_dissector_handle(gssapi_oid_value *next_level_value) {
if (next_level_value == NULL) {
return NULL;
}
return next_level_value->handle;
}
static void
dissect_parse_error(tvbuff_t *tvb, int offset, packet_info *pinfo,
proto_tree *tree, const char *field_name, int ret)
{
const char *errstr;
errstr = asn1_err_to_str(ret);
if (tree != NULL) {
proto_tree_add_text(tree, tvb, offset, 0,
"ERROR: Couldn't parse %s: %s", field_name, errstr);
call_dissector(data_handle,
tvb_new_subset(tvb, offset, -1, -1), pinfo, tree);
}
}
/*
* This is the SPNEGO KRB5 dissector. It is not true KRB5, but some ASN.1
* wrapped blob with an OID, USHORT token ID, and a Ticket, that is also
* ASN.1 wrapped by the looks of it. It conforms to RFC1964.
*/
#define KRB_TOKEN_AP_REQ 0x0001
#define KRB_TOKEN_AP_REP 0x0002
#define KRB_TOKEN_AP_ERR 0x0003
#define KRB_TOKEN_GETMIC 0x0101
#define KRB_TOKEN_WRAP 0x0102
#define KRB_TOKEN_DELETE_SEC_CONTEXT 0x0201
static const value_string spnego_krb5_tok_id_vals[] = {
{ KRB_TOKEN_AP_REQ, "KRB5_AP_REQ"},
{ KRB_TOKEN_AP_REP, "KRB5_AP_REP"},
{ KRB_TOKEN_AP_ERR, "KRB5_ERROR"},
{ KRB_TOKEN_GETMIC, "KRB5_GSS_GetMIC" },
{ KRB_TOKEN_WRAP, "KRB5_GSS_Wrap" },
{ KRB_TOKEN_DELETE_SEC_CONTEXT, "KRB5_GSS_Delete_sec_context" },
{ 0, NULL}
};
#define KRB_SGN_ALG_DES_MAC_MD5 0x0000
#define KRB_SGN_ALG_MD2_5 0x0001
#define KRB_SGN_ALG_DES_MAC 0x0002
#define KRB_SGN_ALG_HMAC 0x0011
static const value_string spnego_krb5_sgn_alg_vals[] = {
{ KRB_SGN_ALG_DES_MAC_MD5, "DES MAC MD5"},
{ KRB_SGN_ALG_MD2_5, "MD2.5"},
{ KRB_SGN_ALG_DES_MAC, "DES MAC"},
{ KRB_SGN_ALG_HMAC, "HMAC"},
{ 0, NULL}
};
#define KRB_SEAL_ALG_DES_CBC 0x0000
#define KRB_SEAL_ALG_RC4 0x0010
#define KRB_SEAL_ALG_NONE 0xffff
static const value_string spnego_krb5_seal_alg_vals[] = {
{ KRB_SEAL_ALG_DES_CBC, "DES CBC"},
{ KRB_SEAL_ALG_RC4, "RC4"},
{ KRB_SEAL_ALG_NONE, "None"},
{ 0, NULL}
};
/*
* XXX - is this for SPNEGO or just GSS-API?
* RFC 1964 is "The Kerberos Version 5 GSS-API Mechanism"; presumably one
* can directly designate Kerberos V5 as a mechanism in GSS-API, rather
* than designating SPNEGO as the mechanism, offering Kerberos V5, and
* getting it accepted.
*/
static int
dissect_spnego_krb5_getmic_base(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree);
static int
dissect_spnego_krb5_wrap_base(tvbuff_t *tvb, int offset, packet_info *pinfo, proto_tree *tree, guint16 token_id);
static void
dissect_spnego_krb5(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *item;
proto_tree *subtree;
int ret, offset = 0;
ASN1_SCK hnd;
gboolean def;
guint len1, cls, con, tag, oid_len, nbytes;
guint16 token_id;
subid_t *oid;
gchar *oid_string;
gssapi_oid_value *value;
tvbuff_t *krb5_tvb;
item = proto_tree_add_item(tree, hf_spnego_krb5, tvb, offset,
-1, FALSE);
subtree = proto_item_add_subtree(item, ett_spnego_krb5);
/*
* The KRB5 blob conforms to RFC1964:
* [APPLICATION 0] {
* OID,
* USHORT (0x0001 == AP-REQ, 0x0002 == AP-REP, 0x0003 == ERROR),
* OCTET STRING }
*
* However, for some protocols, the KRB5 blob starts at the SHORT
* and has no DER encoded header etc.
*
* It appears that for some other protocols the KRB5 blob is just
* a Kerberos message, with no [APPLICATION 0] header, no OID,
* and no USHORT.
*
* So:
*
* If we see an [APPLICATION 0] HEADER, we show the OID and
* the USHORT, and then dissect the rest as a Kerberos message.
*
* If we see an [APPLICATION 14] or [APPLICATION 15] header,
* we assume it's an AP-REQ or AP-REP message, and dissect
* it all as a Kerberos message.
*
* Otherwise, we show the USHORT, and then dissect the rest
* as a Kerberos message.
*/
asn1_open(&hnd, tvb, offset);
/*
* Get the first header ...
*/
ret = asn1_header_decode(&hnd, &cls, &con, &tag, &def, &len1);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, subtree,
"SPNEGO KRB5 Header", ret);
goto done;
}
if (cls == ASN1_APL && con == ASN1_CON) {
/*
* [APPLICATION <tag>]
*/
switch (tag) {
case 0:
/*
* [APPLICATION 0]
*/
offset = hnd.offset;
/* Next, the OID */
ret = asn1_oid_decode(&hnd, &oid, &oid_len, &nbytes);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, subtree,
"SPNEGO supportedMech token", ret);
goto done;
}
oid_string = format_oid(oid, oid_len);
value = gssapi_lookup_oid(oid, oid_len);
if (value)
proto_tree_add_text(subtree, tvb, offset, nbytes,
"OID: %s (%s)",
oid_string, value->comment);
else
proto_tree_add_text(subtree, tvb, offset, nbytes,
"OID: %s",
oid_string);
g_free(oid_string);
offset += nbytes;
/* Next, the token ID ... */
token_id = tvb_get_letohs(tvb, offset);
proto_tree_add_uint(subtree, hf_spnego_krb5_tok_id, tvb, offset, 2,
token_id);
hnd.offset += 2;
offset += 2;
break;
case 14: /* [APPLICATION 14] */
case 15: /* [APPLICATION 15] */
/*
* No token ID - just dissect as a Kerberos message and
* return.
*/
krb5_tvb = tvb_new_subset(tvb, offset, -1, -1);
offset = dissect_kerberos_main(krb5_tvb, pinfo, subtree, FALSE, NULL);
return;
default:
proto_tree_add_text(subtree, tvb, offset, 0,
"Unknown header (cls=%d, con=%d, tag=%d)",
cls, con, tag);
goto done;
}
} else {
/* Next, the token ID ... */
token_id = tvb_get_letohs(tvb, offset);
proto_tree_add_uint(subtree, hf_spnego_krb5_tok_id, tvb, offset, 2,
token_id);
hnd.offset += 2;
offset += 2;
}
switch (token_id) {
case KRB_TOKEN_AP_REQ:
case KRB_TOKEN_AP_REP:
case KRB_TOKEN_AP_ERR:
krb5_tvb = tvb_new_subset(tvb, offset, -1, -1);
offset = dissect_kerberos_main(krb5_tvb, pinfo, subtree, FALSE, NULL);
break;
case KRB_TOKEN_GETMIC:
offset = dissect_spnego_krb5_getmic_base(tvb, offset, pinfo, subtree);
break;
case KRB_TOKEN_WRAP:
offset = dissect_spnego_krb5_wrap_base(tvb, offset, pinfo, subtree, token_id);
break;
case KRB_TOKEN_DELETE_SEC_CONTEXT:
break;
default:
break;
}
done:
return;
}
#ifdef HAVE_KERBEROS
#include <epan/crypt-md5.h>
#ifndef KEYTYPE_ARCFOUR_56
# define KEYTYPE_ARCFOUR_56 24
#endif
/* XXX - We should probably do a configure-time check for this instead */
#ifndef KRB5_KU_USAGE_SEAL
# define KRB5_KU_USAGE_SEAL 22
#endif
static int
arcfour_mic_key(void *key_data, size_t key_size, int key_type,
void *cksum_data, size_t cksum_size,
void *key6_data)
{
guint8 k5_data[16];
guint8 T[4];
memset(T, 0, 4);
if (key_type == KEYTYPE_ARCFOUR_56) {
guint8 L40[14] = "fortybits";
memcpy(L40 + 10, T, sizeof(T));
md5_hmac(
L40, 14,
key_data,
key_size,
k5_data);
memset(&k5_data[7], 0xAB, 9);
} else {
md5_hmac(
T, 4,
key_data,
key_size,
k5_data);
}
md5_hmac(
cksum_data, cksum_size,
k5_data,
16,
key6_data);
return 0;
}
static int
usage2arcfour(int usage)
{
switch (usage) {
case 3: /*KRB5_KU_AS_REP_ENC_PART 3 */
case 9: /*KRB5_KU_TGS_REP_ENC_PART_SUB_KEY 9 */
return 8;
case 22: /*KRB5_KU_USAGE_SEAL 22 */
return 13;
case 23: /*KRB5_KU_USAGE_SIGN 23 */
return 15;
case 24: /*KRB5_KU_USAGE_SEQ 24 */
return 0;
default :
return 0;
}
}
static int
arcfour_mic_cksum(guint8 *key_data, int key_length,
unsigned usage,
u_char sgn_cksum[8],
const void *v1, size_t l1,
const void *v2, size_t l2,
const void *v3, size_t l3)
{
const guint8 signature[] = "signaturekey";
guint8 ksign_c[16];
unsigned char t[4];
md5_state_t ms;
unsigned char digest[16];
int rc4_usage;
guint8 cksum[16];
rc4_usage=usage2arcfour(usage);
md5_hmac(signature, sizeof(signature),
key_data, key_length,
ksign_c);
md5_init(&ms);
t[0] = (rc4_usage >> 0) & 0xFF;
t[1] = (rc4_usage >> 8) & 0xFF;
t[2] = (rc4_usage >> 16) & 0xFF;
t[3] = (rc4_usage >> 24) & 0xFF;
md5_append(&ms, t, 4);
md5_append(&ms, v1, l1);
md5_append(&ms, v2, l2);
md5_append(&ms, v3, l3);
md5_finish(&ms, digest);
md5_hmac(digest, 16, ksign_c, 16, cksum);
memcpy(sgn_cksum, cksum, 8);
return 0;
}
/*
* Verify padding of a gss wrapped message and return its length.
*/
static int
gssapi_verify_pad(unsigned char *wrapped_data, int wrapped_length,
size_t datalen,
size_t *padlen)
{
unsigned char *pad;
size_t padlength;
int i;
pad = wrapped_data + wrapped_length - 1;
padlength = *pad;
if (padlength > datalen)
return 1;
for (i = padlength; i > 0 && *pad == padlength; i--, pad--)
;
if (i != 0)
return 2;
*padlen = padlength;
return 0;
}
static int
decrypt_arcfour(packet_info *pinfo,
guint8 *input_message_buffer,
guint8 *output_message_buffer,
guint8 *key_value, int key_size, int key_type)
{
guint8 Klocaldata[16];
int ret;
gint32 seq_number;
size_t datalen;
guint8 k6_data[16], SND_SEQ[8], Confounder[8];
guint8 cksum_data[8];
int cmp;
int conf_flag;
size_t padlen = 0;
datalen = tvb_length(pinfo->gssapi_encrypted_tvb);
if(tvb_get_ntohs(pinfo->gssapi_wrap_tvb, 4)==0x1000){
conf_flag=1;
} else if (tvb_get_ntohs(pinfo->gssapi_wrap_tvb, 4)==0xffff){
conf_flag=0;
} else {
return -3;
}
if(tvb_get_ntohs(pinfo->gssapi_wrap_tvb, 6)!=0xffff){
return -4;
}
ret = arcfour_mic_key(key_value, key_size, key_type,
(void *)tvb_get_ptr(pinfo->gssapi_wrap_tvb, 16, 8),
8, /* SGN_CKSUM */
k6_data);
if (ret) {
return -5;
}
{
rc4_state_struct rc4_state;
crypt_rc4_init(&rc4_state, k6_data, sizeof(k6_data));
memcpy(SND_SEQ, (unsigned char *)tvb_get_ptr(pinfo->gssapi_wrap_tvb, 8, 8), 8);
crypt_rc4(&rc4_state, SND_SEQ, 8);
memset(k6_data, 0, sizeof(k6_data));
}
seq_number=g_ntohl(*((guint32 *)SND_SEQ));
cmp = memcmp(&SND_SEQ[4], "\xff\xff\xff\xff", 4);
if(cmp){
cmp = memcmp(&SND_SEQ[4], "\x00\x00\x00\x00", 4);
}
if (cmp != 0) {
return -6;
}
{
int i;
for (i = 0; i < 16; i++)
Klocaldata[i] = ((u_char *)key_value)[i] ^ 0xF0;
}
ret = arcfour_mic_key(Klocaldata,sizeof(Klocaldata),key_type,
SND_SEQ, 4,
k6_data);
memset(Klocaldata, 0, sizeof(Klocaldata));
if (ret) {
return -7;
}
if(conf_flag) {
rc4_state_struct rc4_state;
crypt_rc4_init(&rc4_state, k6_data, sizeof(k6_data));
memcpy(Confounder, (unsigned char *)tvb_get_ptr(pinfo->gssapi_wrap_tvb, 24, 8), 8);
crypt_rc4(&rc4_state, Confounder, 8);
memcpy(output_message_buffer, input_message_buffer, datalen);
crypt_rc4(&rc4_state, output_message_buffer, datalen);
} else {
memcpy(Confounder,
tvb_get_ptr(pinfo->gssapi_wrap_tvb, 24, 8),
8); /* Confounder */
memcpy(output_message_buffer,
input_message_buffer,
datalen);
}
memset(k6_data, 0, sizeof(k6_data));
/* only normal (i.e. non DCE style wrapping use padding ? */
if(pinfo->decrypt_gssapi_tvb==DECRYPT_GSSAPI_NORMAL){
ret = gssapi_verify_pad(output_message_buffer,datalen,datalen, &padlen);
if (ret) {
return -9;
}
datalen -= padlen;
}
/* dont know what the checksum looks like for dce style gssapi */
if(pinfo->decrypt_gssapi_tvb==DECRYPT_GSSAPI_NORMAL){
ret = arcfour_mic_cksum(key_value, key_size,
KRB5_KU_USAGE_SEAL,
cksum_data,
tvb_get_ptr(pinfo->gssapi_wrap_tvb, 0, 8), 8,
Confounder, sizeof(Confounder),
output_message_buffer,
datalen + padlen);
if (ret) {
return -10;
}
cmp = memcmp(cksum_data,
tvb_get_ptr(pinfo->gssapi_wrap_tvb, 16, 8),
8); /* SGN_CKSUM */
if (cmp) {
return -11;
}
}
return datalen;
}
#if defined(HAVE_HEIMDAL_KERBEROS) || defined(HAVE_MIT_KERBEROS)
static void
decrypt_gssapi_krb_arcfour_wrap(proto_tree *tree, packet_info *pinfo, tvbuff_t *tvb, int keytype)
{
int ret;
enc_key_t *ek;
int length;
const guint8 *original_data;
static int omb_index=0;
static guint8 *omb_arr[4]={NULL,NULL,NULL,NULL};
static guint8 *cryptocopy=NULL; /* workaround for pre-0.6.1 heimdal bug */
guint8 *output_message_buffer;
omb_index++;
if(omb_index>=4){
omb_index=0;
}
output_message_buffer=omb_arr[omb_index];
length=tvb_length(pinfo->gssapi_encrypted_tvb);
original_data=tvb_get_ptr(pinfo->gssapi_encrypted_tvb, 0, length);
/* dont do anything if we are not attempting to decrypt data */
/*
if(!krb_decrypt){
return;
}
*/
/* XXX we should only do this for first time, then store somewhere */
/* XXX We also need to re-read the keytab when the preference changes */
cryptocopy=ep_alloc(length);
if(output_message_buffer){
g_free(output_message_buffer);
output_message_buffer=NULL;
}
output_message_buffer=g_malloc(length);
for(ek=enc_key_list;ek;ek=ek->next){
/* shortcircuit and bail out if enctypes are not matching */
if(ek->keytype!=keytype){
continue;
}
/* pre-0.6.1 versions of Heimdal would sometimes change
the cryptotext data even when the decryption failed.
This would obviously not work since we iterate over the
keys. So just give it a copy of the crypto data instead.
This has been seen for RC4-HMAC blobs.
*/
memcpy(cryptocopy, original_data, length);
ret=decrypt_arcfour(pinfo,
cryptocopy,
output_message_buffer,
ek->keyvalue,
ek->keylength,
ek->keytype
);
if (ret >= 0) {
proto_tree_add_text(tree, NULL, 0, 0, "[Decrypted using: %s]", ek->key_origin);
pinfo->gssapi_decrypted_tvb=tvb_new_real_data(
output_message_buffer,
ret, ret);
tvb_set_child_real_data_tvbuff(tvb, pinfo->gssapi_decrypted_tvb);
add_new_data_source(pinfo, pinfo->gssapi_decrypted_tvb, "Decrypted GSS-Krb5");
return;
}
}
return;
}
#endif /* HAVE_HEIMDAL_KERBEROS || HAVE_MIT_KERBEROS */
#endif
/*
* XXX - This is for GSSAPI Wrap tokens ...
*/
static int
dissect_spnego_krb5_wrap_base(tvbuff_t *tvb, int offset, packet_info *pinfo
#ifndef HAVE_KERBEROS
_U_
#endif
, proto_tree *tree, guint16 token_id
#ifndef HAVE_KERBEROS
_U_
#endif
)
{
guint16 sgn_alg, seal_alg;
#ifdef HAVE_KERBEROS
int start_offset=offset;
#endif
/*
* The KRB5 blob conforms to RFC1964:
* USHORT (0x0102 == GSS_Wrap)
* and so on }
*/
/* Now, the sign and seal algorithms ... */
sgn_alg = tvb_get_letohs(tvb, offset);
proto_tree_add_uint(tree, hf_spnego_krb5_sgn_alg, tvb, offset, 2,
sgn_alg);
offset += 2;
seal_alg = tvb_get_letohs(tvb, offset);
proto_tree_add_uint(tree, hf_spnego_krb5_seal_alg, tvb, offset, 2,
seal_alg);
offset += 2;
/* Skip the filler */
offset += 2;
/* Encrypted sequence number */
proto_tree_add_item(tree, hf_spnego_krb5_snd_seq, tvb, offset, 8,
TRUE);
offset += 8;
/* Checksum of plaintext padded data */
proto_tree_add_item(tree, hf_spnego_krb5_sgn_cksum, tvb, offset, 8,
TRUE);
offset += 8;
/*
* At least according to draft-brezak-win2k-krb-rc4-hmac-04,
* if the signing algorithm is KRB_SGN_ALG_HMAC, there's an
* extra 8 bytes of "Random confounder" after the checksum.
* It certainly confounds code expecting all Kerberos 5
* GSS_Wrap() tokens to look the same....
*/
if (sgn_alg == KRB_SGN_ALG_HMAC) {
proto_tree_add_item(tree, hf_spnego_krb5_confounder, tvb, offset, 8,
TRUE);
offset += 8;
}
/* Is the data encrypted? */
pinfo->gssapi_data_encrypted=(seal_alg!=KRB_SEAL_ALG_NONE);
#ifdef HAVE_KERBEROS
#define GSS_ARCFOUR_WRAP_TOKEN_SIZE 32
if(pinfo->decrypt_gssapi_tvb){
/* if the caller did not provide a tvb, then we just use
whatever is left of our current tvb.
*/
if(!pinfo->gssapi_encrypted_tvb){
int len;
len=tvb_reported_length_remaining(tvb,offset);
if(len>tvb_length_remaining(tvb, offset)){
/* no point in trying to decrypt,
we dont have the full pdu.
*/
return offset;
}
pinfo->gssapi_encrypted_tvb = tvb_new_subset(
tvb, offset, len, len);
}
/* if this is KRB5 wrapped rc4-hmac */
if((token_id==KRB_TOKEN_WRAP)
&&(sgn_alg==KRB_SGN_ALG_HMAC)
&&(seal_alg==KRB_SEAL_ALG_RC4)){
/* do we need to create a tvb for the wrapper
as well ?
*/
if(!pinfo->gssapi_wrap_tvb){
pinfo->gssapi_wrap_tvb = tvb_new_subset(
tvb, start_offset-2,
GSS_ARCFOUR_WRAP_TOKEN_SIZE,
GSS_ARCFOUR_WRAP_TOKEN_SIZE);
}
#if defined(HAVE_HEIMDAL_KERBEROS) || defined(HAVE_MIT_KERBEROS)
decrypt_gssapi_krb_arcfour_wrap(tree,
pinfo,
tvb,
23 /* rc4-hmac */);
#endif /* HAVE_HEIMDAL_KERBEROS || HAVE_MIT_KERBEROS */
}
}
#endif
/*
* Return the offset past the checksum, so that we know where
* the data we're wrapped around starts. Also, set the length
* of our top-level item to that offset, so it doesn't cover
* the data we're wrapped around.
*
* Note that for DCERPC the GSSAPI blobs comes after the data it wraps,
* not before.
*/
return offset;
}
/*
* XXX - This is for GSSAPI GetMIC tokens ...
*/
static int
dissect_spnego_krb5_getmic_base(tvbuff_t *tvb, int offset, packet_info *pinfo _U_, proto_tree *tree)
{
guint16 sgn_alg;
/*
* The KRB5 blob conforms to RFC1964:
* USHORT (0x0101 == GSS_GetMIC)
* and so on }
*/
/* Now, the sign algorithm ... */
sgn_alg = tvb_get_letohs(tvb, offset);
proto_tree_add_uint(tree, hf_spnego_krb5_sgn_alg, tvb, offset, 2,
sgn_alg);
offset += 2;
/* Skip the filler */
offset += 4;
/* Encrypted sequence number */
proto_tree_add_item(tree, hf_spnego_krb5_snd_seq, tvb, offset, 8,
TRUE);
offset += 8;
/* Checksum of plaintext padded data */
proto_tree_add_item(tree, hf_spnego_krb5_sgn_cksum, tvb, offset, 8,
TRUE);
offset += 8;
/*
* At least according to draft-brezak-win2k-krb-rc4-hmac-04,
* if the signing algorithm is KRB_SGN_ALG_HMAC, there's an
* extra 8 bytes of "Random confounder" after the checksum.
* It certainly confounds code expecting all Kerberos 5
* GSS_Wrap() tokens to look the same....
*/
if (sgn_alg == KRB_SGN_ALG_HMAC) {
proto_tree_add_item(tree, hf_spnego_krb5_confounder, tvb, offset, 8,
TRUE);
offset += 8;
}
/*
* Return the offset past the checksum, so that we know where
* the data we're wrapped around starts. Also, set the length
* of our top-level item to that offset, so it doesn't cover
* the data we're wrapped around.
*/
return offset;
}
/*
* XXX - is this for SPNEGO or just GSS-API?
* RFC 1964 is "The Kerberos Version 5 GSS-API Mechanism"; presumably one
* can directly designate Kerberos V5 as a mechanism in GSS-API, rather
* than designating SPNEGO as the mechanism, offering Kerberos V5, and
* getting it accepted.
*/
static int
dissect_spnego_krb5_wrap(tvbuff_t *tvb, packet_info *pinfo _U_, proto_tree *tree)
{
proto_item *item;
proto_tree *subtree;
int offset = 0;
guint16 token_id;
item = proto_tree_add_item(tree, hf_spnego_krb5, tvb, 0, -1, FALSE);
subtree = proto_item_add_subtree(item, ett_spnego_krb5);
/*
* The KRB5 blob conforms to RFC1964:
* USHORT (0x0102 == GSS_Wrap)
* and so on }
*/
/* First, the token ID ... */
token_id = tvb_get_letohs(tvb, offset);
proto_tree_add_uint(subtree, hf_spnego_krb5_tok_id, tvb, offset, 2,
token_id);
offset += 2;
offset = dissect_spnego_krb5_wrap_base(tvb, offset, pinfo, subtree, token_id);
/*
* Return the offset past the checksum, so that we know where
* the data we're wrapped around starts. Also, set the length
* of our top-level item to that offset, so it doesn't cover
* the data we're wrapped around.
*/
proto_item_set_len(item, offset);
return offset;
}
/* Spnego stuff from here */
static int
dissect_spnego_mechTypes(tvbuff_t *tvb, int offset, packet_info *pinfo,
proto_tree *tree,
gssapi_oid_value **next_level_value_p)
{
proto_item *item = NULL;
proto_tree *subtree = NULL;
gboolean saw_mechanism = FALSE;
int start_offset, start_oid_offset, end_oid_offset;
gint8 class;
gboolean pc, ind_field;
gint32 tag;
guint32 len1;
gchar oid[MAX_OID_STR_LEN];
start_offset=offset;
/*
* MechTypeList ::= SEQUENCE OF MechType
*/
offset = get_ber_identifier(tvb, offset, &class, &pc, &tag);
offset = get_ber_length(tree, tvb, offset, &len1, &ind_field);
if (!(class == BER_CLASS_UNI && pc && tag == BER_UNI_TAG_SEQUENCE)) {
proto_tree_add_text(
tree, tvb, offset, 0,
"Unknown header (class=%d, pc=%d, tag=%d)",
class, pc, tag);
goto done;
}
item = proto_tree_add_item(tree, hf_spnego_mechtype, tvb,
start_offset, len1, FALSE);
subtree = proto_item_add_subtree(item, ett_spnego_mechtype);
/*
* Now, the object IDs ...
*/
start_oid_offset=offset;
end_oid_offset = start_oid_offset+len1;
while (offset<end_oid_offset) {
gssapi_oid_value *value;
offset=dissect_ber_object_identifier(FALSE, pinfo, subtree, tvb, offset, hf_spnego_mech, oid);
value = gssapi_lookup_oid_str(oid);
/*
* Tell our caller the first mechanism we see, so that if
* this is a negTokenInit with a mechToken, it can interpret
* the mechToken according to the first mechType. (There
* might not have been any indication of the mechType
* in prior frames, so we can't necessarily use the
* mechanism from the conversation; i.e., a negTokenInit
* can contain the initial security token for the desired
* mechanism of the initiator - that's the first mechanism
* in the list.)
*/
if (!saw_mechanism) {
if (value)
*next_level_value_p = value;
saw_mechanism = TRUE;
}
}
done:
return offset;
}
static int
dissect_spnego_reqFlags(tvbuff_t *tvb, int offset, packet_info *pinfo _U_,
proto_tree *tree, ASN1_SCK *hnd)
{
gboolean def;
guint len1, cls, con, tag, flags;
int ret;
proto_item *item;
proto_tree *subtree;
ret = asn1_header_decode(hnd, &cls, &con, &tag, &def, &len1);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, tree,
"SPNEGO reqFlags header", ret);
goto done;
}
if (!(cls == ASN1_UNI && con == ASN1_PRI && tag == ASN1_BTS)) {
proto_tree_add_text(
tree, tvb, offset, 0,
"Unknown header (cls=%d, con=%d, tag=%d)",
cls, con, tag);
goto done;
}
/* We must have a Bit String ... insert it */
offset = hnd->offset;
flags = tvb_get_guint8(tvb, offset);
item = proto_tree_add_item(tree, hf_spnego_reqflags, tvb, offset, len1,
FALSE);
subtree = proto_item_add_subtree(item, ett_spnego_reqflags);
/*
* Now, the bits. XXX: Assume 8 bits. FIXME.
*/
proto_tree_add_boolean(subtree, hf_gssapi_reqflags_deleg, tvb, offset, len1, flags);
proto_tree_add_boolean(subtree, hf_gssapi_reqflags_mutual, tvb, offset, len1, flags);
proto_tree_add_boolean(subtree, hf_gssapi_reqflags_replay, tvb, offset, len1, flags);
proto_tree_add_boolean(subtree, hf_gssapi_reqflags_sequence, tvb, offset, len1, flags);
proto_tree_add_boolean(subtree, hf_gssapi_reqflags_anon, tvb, offset, len1, flags);
proto_tree_add_boolean(subtree, hf_gssapi_reqflags_conf, tvb, offset, len1, flags);
proto_tree_add_boolean(subtree, hf_gssapi_reqflags_integ, tvb, offset, len1, flags);
hnd->offset += len1;
done:
return offset + len1;
}
static int
dissect_spnego_mechToken(tvbuff_t *tvb, int offset, packet_info *pinfo _U_,
proto_tree *tree, ASN1_SCK *hnd,
dissector_handle_t next_level_dissector)
{
proto_item *item;
proto_tree *subtree;
gboolean def;
int ret;
guint cls, con, tag, nbytes = 0;
gint length_remaining, reported_length_remaining;
tvbuff_t *token_tvb;
/*
* This appears to be a simple octet string ...
*/
ret = asn1_header_decode(hnd, &cls, &con, &tag, &def, &nbytes);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, tree,
"SPNEGO sequence header", ret);
goto done;
}
if (!(cls == ASN1_UNI && con == ASN1_PRI && tag == ASN1_OTS)) {
proto_tree_add_text(
tree, tvb, offset, 0,
"Unknown header (cls=%d, con=%d, tag=%d)",
cls, con, tag);
goto done;
}
offset = hnd->offset;
/* Dont try to create an item with more bytes than remains in the
* frame or we will not even attempt to dissect those bytes we
* do have. (since there will be an exception)
*
* We use "tvb_ensure_length_remaining()" so that we throw
* an exception if there's nothing to dissect.
*/
length_remaining = tvb_ensure_length_remaining(tvb,offset);
reported_length_remaining = tvb_reported_length_remaining(tvb,offset);
if ((guint)length_remaining > nbytes)
length_remaining = nbytes;
if ((guint)reported_length_remaining > nbytes)
reported_length_remaining = nbytes;
item = proto_tree_add_item(tree, hf_spnego_mechtoken, tvb, offset,
length_remaining, FALSE);
subtree = proto_item_add_subtree(item, ett_spnego_mechtoken);
/*
* Now, we should be able to dispatch after creating a new TVB.
*/
token_tvb = tvb_new_subset(tvb, offset, length_remaining,
reported_length_remaining);
if (next_level_dissector)
call_dissector(next_level_dissector, token_tvb, pinfo, subtree);
hnd->offset += nbytes; /* Update this ... */
done:
return offset + nbytes;
}
static int
dissect_spnego_mechListMIC(tvbuff_t *tvb, int offset, packet_info *pinfo _U_,
proto_tree *tree, ASN1_SCK *hnd,
dissector_handle_t next_level_dissector)
{
guint len1, cls, con, tag;
int ret;
gboolean def;
proto_tree *subtree = NULL;
/*
* Add the mechListMIC [3] Octet String or General String ...
*/
ret = asn1_header_decode(hnd, &cls, &con, &tag, &def, &len1);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, subtree,
"SPNEGO sequence header", ret);
goto done;
}
offset = hnd->offset;
if (cls == ASN1_UNI && con == ASN1_CON && tag == ASN1_SEQ) {
/*
* There seems to be two different forms this can take
* One as an Octet string, and one as a general string in a
* sequence ... We will have to dissect this later
*/
proto_tree_add_text(tree, tvb, offset + 4, len1 - 4,
"mechListMIC: %s",
tvb_format_text(tvb, offset + 4, len1 - 4));
/* Naughty ... but we have to adjust for what we never took */
hnd->offset += len1;
offset += len1;
}
else if (cls == ASN1_UNI && con == ASN1_PRI && tag == ASN1_OTS) {
tvbuff_t *token_tvb;
proto_item *item;
proto_tree *subtree;
item = proto_tree_add_item(tree, hf_spnego_mechlistmic, tvb, offset,
len1, FALSE);
subtree = proto_item_add_subtree(item, ett_spnego_mechlistmic);
/*
* Now, we should be able to dispatch after creating a new TVB.
*/
token_tvb = tvb_new_subset(tvb, offset, len1, -1);
if (next_level_dissector)
call_dissector(next_level_dissector, token_tvb, pinfo, subtree);
hnd->offset += len1; /* Update this ... */
offset += len1;
}
else {
proto_tree_add_text(subtree, tvb, offset, 0,
"Unknown header (cls=%d, con=%d, tag=%d)",
cls, con, tag);
goto done;
}
done:
return offset;
}
static int
dissect_spnego_negTokenInit(tvbuff_t *tvb, int offset, packet_info *pinfo _U_,
proto_tree *tree, ASN1_SCK *hnd,
gssapi_oid_value **next_level_value_p)
{
proto_item *item;
proto_tree *subtree;
gboolean def;
guint len1, len, cls, con, tag;
int ret;
item = proto_tree_add_item( tree, hf_spnego_negtokeninit, tvb, offset,
-1, FALSE);
subtree = proto_item_add_subtree(item, ett_spnego_negtokeninit);
/*
* Here is what we need to get ...
* NegTokenInit ::= SEQUENCE {
* mechTypes [0] MechTypeList OPTIONAL,
* reqFlags [1] ContextFlags OPTIONAL,
* mechToken [2] OCTET STRING OPTIONAL,
* mechListMIC [3] OCTET STRING OPTIONAL }
*/
ret = asn1_header_decode(hnd, &cls, &con, &tag, &def, &len1);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, subtree,
"SPNEGO sequence header", ret);
goto done;
}
if (!(cls == ASN1_UNI && con == ASN1_CON && tag == ASN1_SEQ)) {
proto_tree_add_text(
subtree, tvb, offset, 0,
"Unknown header (cls=%d, con=%d, tag=%d)",
cls, con, tag);
goto done;
}
offset = hnd->offset;
while (len1) {
int hdr_ofs;
hdr_ofs = hnd->offset;
ret = asn1_header_decode(hnd, &cls, &con, &tag, &def, &len);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, subtree,
"SPNEGO context header", ret);
goto done;
}
if (!(cls == ASN1_CTX && con == ASN1_CON)) {
proto_tree_add_text(subtree, tvb, offset, 0,
"Unknown header (cls=%d, con=%d, tag=%d)",
cls, con, tag);
goto done;
}
/* Adjust for the length of the header */
len1 -= (hnd->offset - hdr_ofs);
/* Should be one of the fields */
switch (tag) {
case SPNEGO_mechTypes:
offset = dissect_spnego_mechTypes(tvb, hnd->offset, pinfo,
subtree,
next_level_value_p);
hnd->offset=offset;
break;
case SPNEGO_reqFlags:
offset = dissect_spnego_reqFlags(tvb, offset, pinfo, subtree, hnd);
break;
case SPNEGO_mechToken:
offset = dissect_spnego_mechToken(tvb, offset, pinfo, subtree,
hnd, gssapi_dissector_handle(*next_level_value_p));
break;
case SPNEGO_mechListMIC:
offset = dissect_spnego_mechListMIC(tvb, offset, pinfo, subtree,
hnd, gssapi_dissector_handle(*next_level_value_p));
break;
default:
break;
}
len1 -= len;
}
done:
return offset; /* Not sure this is right */
}
static int
dissect_spnego_negResult(tvbuff_t *tvb, int offset, packet_info *pinfo _U_,
proto_tree *tree, ASN1_SCK *hnd)
{
gboolean def;
int ret;
guint len, cls, con, tag, val;
ret = asn1_header_decode(hnd, &cls, &con, &tag, &def, &len);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, tree,
"SPNEGO context header", ret);
goto done;
}
if (!(cls == ASN1_UNI && con == ASN1_PRI && tag == ASN1_ENUM)) {
proto_tree_add_text(
tree, tvb, offset, 0,
"Unknown header (cls=%d, con=%d, tag=%d) xxx",
cls, con, tag);
goto done;
}
offset = hnd->offset;
/* Now, get the value */
ret = asn1_uint32_value_decode(hnd, len, &val);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, tree,
"SPNEGO negResult value", ret);
goto done;
}
proto_tree_add_item(tree, hf_spnego_negtokentarg_negresult, tvb,
offset, 1, FALSE);
offset = hnd->offset;
done:
return offset;
}
static int
dissect_spnego_supportedMech(tvbuff_t *tvb, int offset, packet_info *pinfo _U_,
proto_tree *tree, ASN1_SCK *hnd,
gssapi_oid_value **next_level_value_p)
{
int ret;
guint oid_len, nbytes;
subid_t *oid;
gchar *oid_string;
gssapi_oid_value *value;
conversation_t *conversation;
/*
* Now, get the OID, and find the handle, if any
*/
offset = hnd->offset;
ret = asn1_oid_decode(hnd, &oid, &oid_len, &nbytes);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, tree,
"SPNEGO supportedMech token", ret);
goto done;
}
oid_string = format_oid(oid, oid_len);
value = gssapi_lookup_oid(oid, oid_len);
if (value)
proto_tree_add_text(tree, tvb, offset, nbytes,
"supportedMech: %s (%s)",
oid_string, value->comment);
else
proto_tree_add_text(tree, tvb, offset, nbytes, "supportedMech: %s",
oid_string);
g_free(oid_string);
offset += nbytes;
/* Should check for an unrecognized OID ... */
if (value)
*next_level_value_p = value;
/*
* Now, we need to save this in per proto info in the
* conversation if it exists. We also should create a
* conversation if one does not exist. FIXME!
* Hmmm, might need to be smarter, because there can be
* multiple mechTypes in a negTokenInit with one being the
* default used in the Token if present. Then the negTokenTarg
* could override that. :-(
*/
if ((conversation = find_conversation(pinfo->fd->num, &pinfo->src, &pinfo->dst,
pinfo->ptype, pinfo->srcport,
pinfo->destport, 0))) {
conversation_add_proto_data(conversation, proto_spnego,
*next_level_value_p);
}
else {
}
done:
return offset;
}
static int
dissect_spnego_responseToken(tvbuff_t *tvb, int offset, packet_info *pinfo _U_,
proto_tree *tree, ASN1_SCK *hnd,
dissector_handle_t next_level_dissector)
{
gboolean def;
int ret;
guint cls, con, tag, nbytes;
tvbuff_t *token_tvb;
proto_item *item;
proto_tree *subtree;
ret = asn1_header_decode(hnd, &cls, &con, &tag, &def, &nbytes);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, tree,
"SPNEGO sequence header", ret);
goto done;
}
if (!(cls == ASN1_UNI && con == ASN1_PRI && tag == ASN1_OTS)) {
proto_tree_add_text(
tree, tvb, offset, 0,
"Unknown header (cls=%d, con=%d, tag=%d)",
cls, con, tag);
goto done;
}
offset = hnd->offset;
item = proto_tree_add_item(tree, hf_spnego_responsetoken, tvb, offset -2 ,
nbytes + 2, FALSE);
subtree = proto_item_add_subtree(item, ett_spnego_responsetoken);
/*
* Now, we should be able to dispatch after creating a new TVB.
* However, we should make sure that there is something in the
* response token ...
*/
if (nbytes) {
token_tvb = tvb_new_subset(tvb, offset, nbytes, -1);
if (next_level_dissector)
call_dissector(next_level_dissector, token_tvb, pinfo, subtree);
}
else {
proto_tree_add_text(subtree, tvb, offset-2, 2, "<Empty String>");
}
hnd->offset += nbytes; /* Update this ... */
done:
return offset + nbytes;
}
static int
dissect_spnego_negTokenTarg(tvbuff_t *tvb, int offset, packet_info *pinfo _U_,
proto_tree *tree, ASN1_SCK *hnd,
gssapi_oid_value **next_level_value_p)
{
proto_item *item;
proto_tree *subtree;
gboolean def;
int ret;
guint len1, len, cls, con, tag;
item = proto_tree_add_item( tree, hf_spnego_negtokentarg, tvb, offset,
-1, FALSE);
subtree = proto_item_add_subtree(item, ett_spnego_negtokentarg);
/*
* Here is what we need to get ...
* NegTokenTarg ::= SEQUENCE {
* negResult [0] ENUMERATED {
* accept_completed (0),
* accept_incomplete (1),
* reject (2) } OPTIONAL,
* supportedMech [1] MechType OPTIONAL,
* responseToken [2] OCTET STRING OPTIONAL,
* mechListMIC [3] OCTET STRING OPTIONAL }
*/
ret = asn1_header_decode(hnd, &cls, &con, &tag, &def, &len1);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, subtree,
"SPNEGO sequence header", ret);
goto done;
}
if (!(cls == ASN1_UNI && con == ASN1_CON && tag == ASN1_SEQ)) {
proto_tree_add_text(
subtree, tvb, offset, 0,
"Unknown header (cls=%d, con=%d, tag=%d)",
cls, con, tag);
goto done;
}
offset = hnd->offset;
while (len1) {
int hdr_ofs;
hdr_ofs = hnd->offset;
ret = asn1_header_decode(hnd, &cls, &con, &tag, &def, &len);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, subtree,
"SPNEGO context header", ret);
goto done;
}
if (!(cls == ASN1_CTX && con == ASN1_CON)) {
proto_tree_add_text(
subtree, tvb, offset, 0,
"Unknown header (cls=%d, con=%d, tag=%d)",
cls, con, tag);
goto done;
}
/* Adjust for the length of the header */
len1 -= (hnd->offset - hdr_ofs);
/* Should be one of the fields */
switch (tag) {
case SPNEGO_negResult:
offset = dissect_spnego_negResult(tvb, offset, pinfo, subtree,
hnd);
break;
case SPNEGO_supportedMech:
offset = dissect_spnego_supportedMech(tvb, offset, pinfo, subtree,
hnd, next_level_value_p);
break;
case SPNEGO_responseToken:
offset = dissect_spnego_responseToken(tvb, offset, pinfo, subtree,
hnd, gssapi_dissector_handle(*next_level_value_p));
break;
case SPNEGO_mechListMIC:
offset = dissect_spnego_mechListMIC(tvb, offset, pinfo, subtree,
hnd, gssapi_dissector_handle(*next_level_value_p));
break;
default:
break;
}
len1 -= len;
}
done:
return offset;
}
static void
dissect_spnego(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *item;
proto_tree *subtree;
int ret, offset = 0;
ASN1_SCK hnd;
gboolean def;
guint len1, cls, con, tag;
conversation_t *conversation;
gssapi_oid_value *next_level_value;
/*
* We need this later, so lets get it now ...
* It has to be per-frame as there can be more than one GSS-API
* negotiation in a conversation.
*/
next_level_value = p_get_proto_data(pinfo->fd, proto_spnego);
if (!next_level_value && !pinfo->fd->flags.visited) {
/*
* No handle attached to this frame, but it's the first
* pass, so it'd be attached to the conversation.
* If we have a conversation, try to get the handle,
* and if we get one, attach it to the frame.
*/
conversation = find_conversation(pinfo->fd->num, &pinfo->src, &pinfo->dst,
pinfo->ptype, pinfo->srcport,
pinfo->destport, 0);
if (conversation) {
next_level_value = conversation_get_proto_data(conversation,
proto_spnego);
if (next_level_value)
p_add_proto_data(pinfo->fd, proto_spnego, next_level_value);
}
}
item = proto_tree_add_item(tree, hf_spnego, tvb, offset,
-1, FALSE);
subtree = proto_item_add_subtree(item, ett_spnego);
/*
* The TVB contains a [0] header and a sequence that consists of an
* object ID and a blob containing the data ...
* Actually, it contains, according to RFC2478:
* NegotiationToken ::= CHOICE {
* negTokenInit [0] NegTokenInit,
* negTokenTarg [1] NegTokenTarg }
* NegTokenInit ::= SEQUENCE {
* mechTypes [0] MechTypeList OPTIONAL,
* reqFlags [1] ContextFlags OPTIONAL,
* mechToken [2] OCTET STRING OPTIONAL,
* mechListMIC [3] OCTET STRING OPTIONAL }
* NegTokenTarg ::= SEQUENCE {
* negResult [0] ENUMERATED {
* accept_completed (0),
* accept_incomplete (1),
* reject (2) } OPTIONAL,
* supportedMech [1] MechType OPTIONAL,
* responseToken [2] OCTET STRING OPTIONAL,
* mechListMIC [3] OCTET STRING OPTIONAL }
*
* Windows typically includes mechTypes and mechListMic ('NONE'
* in the case of NTLMSSP only).
* It seems to duplicate the responseToken into the mechListMic field
* as well. Naughty, naughty.
*
*/
asn1_open(&hnd, tvb, offset);
/*
* Get the first header ...
*/
ret = asn1_header_decode(&hnd, &cls, &con, &tag, &def, &len1);
if (ret != ASN1_ERR_NOERROR) {
dissect_parse_error(tvb, offset, pinfo, subtree,
"SPNEGO context header", ret);
goto done;
}
if (!(cls == ASN1_CTX && con == ASN1_CON)) {
proto_tree_add_text(
subtree, tvb, offset, 0,
"Unknown header (cls=%d, con=%d, tag=%d)",
cls, con, tag);
goto done;
}
offset = hnd.offset;
/*
* The Tag is one of negTokenInit or negTokenTarg
*/
switch (tag) {
case SPNEGO_negTokenInit:
offset = dissect_spnego_negTokenInit(tvb, offset, pinfo,
subtree, &hnd,
&next_level_value);
break;
case SPNEGO_negTokenTarg:
offset = dissect_spnego_negTokenTarg(tvb, offset, pinfo,
subtree, &hnd,
&next_level_value);
break;
default: /* Broken, what to do? */
break;
}
done:
asn1_close(&hnd, &offset);
}
static int
dissect_spnego_wrap(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
proto_item *item;
proto_tree *subtree;
int return_offset;
conversation_t *conversation;
gssapi_oid_value *next_level_value;
tvbuff_t *token_tvb;
int len, offset, start_offset;
gint8 class;
gboolean pc, ind_field;
gint32 tag;
guint32 len1;
gchar oid[MAX_OID_STR_LEN];
start_offset=0;
offset=start_offset;
/*
* We need this later, so lets get it now ...
* It has to be per-frame as there can be more than one GSS-API
* negotiation in a conversation.
*/
next_level_value = p_get_proto_data(pinfo->fd, proto_spnego);
if (!next_level_value && !pinfo->fd->flags.visited) {
/*
* No handle attached to this frame, but it's the first
* pass, so it'd be attached to the conversation.
* If we have a conversation, try to get the handle,
* and if we get one, attach it to the frame.
*/
conversation = find_conversation(pinfo->fd->num, &pinfo->src, &pinfo->dst,
pinfo->ptype, pinfo->srcport,
pinfo->destport, 0);
if (conversation) {
next_level_value = conversation_get_proto_data(conversation,
proto_spnego);
if (next_level_value)
p_add_proto_data(pinfo->fd, proto_spnego, next_level_value);
}
}
item = proto_tree_add_item(tree, hf_spnego, tvb, offset,
-1, FALSE);
subtree = proto_item_add_subtree(item, ett_spnego);
/*
* The TVB contains a [0] header and a sequence that consists of an
* object ID and a blob containing the data ...
* XXX - is this RFC 2743's "Mechanism-Independent Token Format",
* with the "optional" "use in non-initial tokens" being chosen.
*/
/*
* Get the first header ...
*/
offset = get_ber_identifier(tvb, offset, &class, &pc, &tag);
offset = get_ber_length(tree, tvb, offset, &len1, &ind_field);
if (!(class == BER_CLASS_APP && pc && tag == 0)) {
proto_tree_add_text(
subtree, tvb, start_offset, 0,
"Unknown header (class=%d, pc=%d, tag=%d)",
class, pc, tag);
return_offset = tvb_length(tvb);
goto done;
}
/*
* Get the OID, and find the handle, if any
*
* XXX - what should we do if this OID doesn't match the value
* attached to the frame or conversation? (That would be
* bogus, but that's not impossible - some broken implementation
* might negotiate some security mechanism but put the OID
* for some other security mechanism in GSS_Wrap tokens.)
*/
offset=dissect_ber_object_identifier(FALSE, pinfo, subtree, tvb, offset, hf_spnego_this_mech, oid);
next_level_value = gssapi_lookup_oid_str(oid);
/*
* Now dissect the GSS_Wrap token; it's assumed to be in the
* rest of the tvbuff.
*/
item = proto_tree_add_item(tree, hf_spnego_wraptoken, tvb, offset,
-1, FALSE);
subtree = proto_item_add_subtree(item, ett_spnego_wraptoken);
/*
* Now, we should be able to dispatch after creating a new TVB.
* The subdissector must return the length of the part of the
* token it dissected, so we can return the length of the part
* we (and it) dissected.
*/
token_tvb = tvb_new_subset(tvb, offset, -1, -1);
if (next_level_value->wrap_handle) {
len = call_dissector(next_level_value->wrap_handle, token_tvb, pinfo, subtree);
if (len == 0)
return_offset = tvb_length(tvb);
else
return_offset = offset + len;
} else
return_offset = tvb_length(tvb);
done:
return return_offset;
}
void
proto_register_spnego(void)
{
static hf_register_info hf[] = {
{ &hf_spnego,
{ "SPNEGO", "spnego", FT_NONE, BASE_NONE, NULL, 0x0,
"SPNEGO", HFILL }},
{ &hf_spnego_mech, {
"Mech", "spnego.mech", FT_STRING, BASE_NONE,
NULL, 0, "This is a SPNEGO Object Identifier", HFILL }},
{ &hf_spnego_this_mech, {
"thisMech", "spnego.this_mech", FT_STRING, BASE_NONE,
NULL, 0, "This is a SPNEGO Object Identifier", HFILL }},
{ &hf_spnego_negtokeninit,
{ "negTokenInit", "spnego.negtokeninit", FT_NONE, BASE_NONE,
NULL, 0x0, "SPNEGO negTokenInit", HFILL}},
{ &hf_spnego_negtokentarg,
{ "negTokenTarg", "spnego.negtokentarg", FT_NONE, BASE_NONE,
NULL, 0x0, "SPNEGO negTokenTarg", HFILL}},
{ &hf_spnego_mechtype,
{ "mechType", "spnego.negtokeninit.mechtype", FT_NONE,
BASE_NONE, NULL, 0x0, "SPNEGO negTokenInit mechTypes", HFILL}},
{ &hf_spnego_mechtoken,
{ "mechToken", "spnego.negtokeninit.mechtoken", FT_NONE,
BASE_NONE, NULL, 0x0, "SPNEGO negTokenInit mechToken", HFILL}},
{ &hf_spnego_mechlistmic,
{ "mechListMIC", "spnego.mechlistmic", FT_NONE,
BASE_NONE, NULL, 0x0, "SPNEGO mechListMIC", HFILL}},
{ &hf_spnego_responsetoken,
{ "responseToken", "spnego.negtokentarg.responsetoken",
FT_NONE, BASE_NONE, NULL, 0x0, "SPNEGO responseToken",
HFILL}},
{ &hf_spnego_negtokentarg_negresult,
{ "negResult", "spnego.negtokeninit.negresult", FT_UINT16,
BASE_HEX, VALS(spnego_negResult_vals), 0, "negResult", HFILL}},
{ &hf_spnego_reqflags,
{ "reqFlags", "spnego.negtokeninit.reqflags", FT_BYTES,
BASE_HEX, NULL, 0, "reqFlags", HFILL }},
{ &hf_gssapi_reqflags_deleg,
{ "Delegation", "gssapi.reqflags.deleg", FT_BOOLEAN, 8,
TFS(&tfs_reqflags_deleg), 0x01, "Delegation", HFILL }},
{ &hf_gssapi_reqflags_mutual,
{ "Mutual Authentication", "gssapi.reqflags.mutual", FT_BOOLEAN,
8, TFS(&tfs_reqflags_mutual), 0x02, "Mutual Authentication", HFILL}},
{ &hf_gssapi_reqflags_replay,
{ "Replay Detection", "gssapi.reqflags.replay", FT_BOOLEAN,
8, TFS(&tfs_reqflags_replay), 0x04, "Replay Detection", HFILL}},
{ &hf_gssapi_reqflags_sequence,
{ "Out-of-sequence Detection", "gssapi.reqflags.sequence",
FT_BOOLEAN, 8, TFS(&tfs_reqflags_sequence), 0x08,
"Out-of-sequence Detection", HFILL}},
{ &hf_gssapi_reqflags_anon,
{ "Anonymous Authentication", "gssapi.reqflags.anon",
FT_BOOLEAN, 8, TFS(&tfs_reqflags_anon), 0x10,
"Anonymous Authentication", HFILL}},
{ &hf_gssapi_reqflags_conf,
{ "Per-message Confidentiality", "gssapi.reqflags.conf",
FT_BOOLEAN, 8, TFS(&tfs_reqflags_conf), 0x20,
"Per-message Confidentiality", HFILL}},
{ &hf_gssapi_reqflags_integ,
{ "Per-message Integrity", "gssapi.reqflags.integ",
FT_BOOLEAN, 8, TFS(&tfs_reqflags_integ), 0x40,
"Per-message Integrity", HFILL}},
{ &hf_spnego_wraptoken,
{ "wrapToken", "spnego.wraptoken",
FT_NONE, BASE_NONE, NULL, 0x0, "SPNEGO wrapToken",
HFILL}},
{ &hf_spnego_krb5,
{ "krb5_blob", "spnego.krb5.blob", FT_BYTES,
BASE_NONE, NULL, 0, "krb5_blob", HFILL }},
{ &hf_spnego_krb5_tok_id,
{ "krb5_tok_id", "spnego.krb5.tok_id", FT_UINT16, BASE_HEX,
VALS(spnego_krb5_tok_id_vals), 0, "KRB5 Token Id", HFILL}},
{ &hf_spnego_krb5_sgn_alg,
{ "krb5_sgn_alg", "spnego.krb5.sgn_alg", FT_UINT16, BASE_HEX,
VALS(spnego_krb5_sgn_alg_vals), 0, "KRB5 Signing Algorithm", HFILL}},
{ &hf_spnego_krb5_seal_alg,
{ "krb5_seal_alg", "spnego.krb5.seal_alg", FT_UINT16, BASE_HEX,
VALS(spnego_krb5_seal_alg_vals), 0, "KRB5 Sealing Algorithm", HFILL}},
{ &hf_spnego_krb5_snd_seq,
{ "krb5_snd_seq", "spnego.krb5.snd_seq", FT_BYTES, BASE_NONE,
NULL, 0, "KRB5 Encrypted Sequence Number", HFILL}},
{ &hf_spnego_krb5_sgn_cksum,
{ "krb5_sgn_cksum", "spnego.krb5.sgn_cksum", FT_BYTES, BASE_NONE,
NULL, 0, "KRB5 Data Checksum", HFILL}},
{ &hf_spnego_krb5_confounder,
{ "krb5_confounder", "spnego.krb5.confounder", FT_BYTES, BASE_NONE,
NULL, 0, "KRB5 Confounder", HFILL}},
};
static gint *ett[] = {
&ett_spnego,
&ett_spnego_negtokeninit,
&ett_spnego_negtokentarg,
&ett_spnego_mechtype,
&ett_spnego_mechtoken,
&ett_spnego_mechlistmic,
&ett_spnego_responsetoken,
&ett_spnego_wraptoken,
&ett_spnego_krb5,
};
proto_spnego = proto_register_protocol(
"Spnego", "Spnego", "spnego");
proto_spnego_krb5 = proto_register_protocol("SPNEGO-KRB5",
"SPNEGO-KRB5",
"spnego-krb5");
proto_register_field_array(proto_spnego, hf, array_length(hf));
proto_register_subtree_array(ett, array_length(ett));
}
void
proto_reg_handoff_spnego(void)
{
dissector_handle_t spnego_handle, spnego_wrap_handle;
dissector_handle_t spnego_krb5_handle, spnego_krb5_wrap_handle;
/* Register protocol with GSS-API module */
spnego_handle = create_dissector_handle(dissect_spnego, proto_spnego);
spnego_wrap_handle = new_create_dissector_handle(dissect_spnego_wrap,
proto_spnego);
gssapi_init_oid("1.3.6.1.5.5.2", proto_spnego, ett_spnego,
spnego_handle, spnego_wrap_handle,
"SPNEGO - Simple Protected Negotiation");
/* Register both the one MS created and the real one */
/*
* Thanks to Jean-Baptiste Marchand and Richard B Ward, the
* mystery of the MS KRB5 OID is cleared up. It was due to a library
* that did not handle OID components greater than 16 bits, and was
* fixed in Win2K SP2 as well as WinXP.
* See the archive of <ietf-krb-wg@anl.gov> for the thread topic
* SPNEGO implementation issues. 3-Dec-2002.
*/
spnego_krb5_handle = create_dissector_handle(dissect_spnego_krb5,
proto_spnego_krb5);
spnego_krb5_wrap_handle = new_create_dissector_handle(dissect_spnego_krb5_wrap,
proto_spnego_krb5);
gssapi_init_oid("1.2.840.48018.1.2.2", proto_spnego_krb5, ett_spnego_krb5,
spnego_krb5_handle, spnego_krb5_wrap_handle,
"MS KRB5 - Microsoft Kerberos 5");
gssapi_init_oid("1.2.840.113554.1.2.2", proto_spnego_krb5, ett_spnego_krb5,
spnego_krb5_handle, spnego_krb5_wrap_handle,
"KRB5 - Kerberos 5");
gssapi_init_oid("1.2.840.113554.1.2.2.3", proto_spnego_krb5, ett_spnego_krb5,
spnego_krb5_handle, spnego_krb5_wrap_handle,
"KRB5 - Kerberos 5 - User to User");
/*
* Find the data handle for some calls
*/
data_handle = find_dissector("data");
}
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