spnego.c revision ddad35552931651426ad70912d29d9ab7d2a8d80
/*
* Copyright (C) 2006-2008 Internet Systems Consortium, Inc. ("ISC")
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: spnego.c,v 1.8 2008/04/03 06:09:04 tbox Exp $ */
/*! \file
* \brief
* Portable SPNEGO implementation.
*
* This is part of a portable implementation of the SPNEGO protocol
* (RFCs 2478 and 4178). This implementation uses the RFC 4178 ASN.1
* module but is not a full implementation of the RFC 4178 protocol;
* at the moment, we only support GSS-TSIG with Kerberos
* authentication, so we only need enough of the SPNEGO protocol to
* support that.
*
* The files that make up this portable SPNEGO implementation are:
* \li spnego.c (this file)
* \li spnego.h (API SPNEGO exports to the rest of lib/dns)
* \li spnego.asn1 (SPNEGO ASN.1 module)
* \li spnego_asn1.c (routines generated from spngo.asn1)
* \li spnego_asn1.pl (perl script to generate spnego_asn1.c)
*
* Everything but the functions exported in spnego.h is static, to
* avoid possible conflicts with other libraries (particularly Heimdal,
* since much of this code comes from Heimdal by way of mod_auth_kerb).
*
* spnego_asn1.c is shipped as part of lib/dns because generating it
* requires both Perl and the Heimdal ASN.1 compiler. See
* spnego_asn1.pl for further details. We've tried to eliminate all
* compiler warnings from the generated code, but you may see a few
* when using a compiler version we haven't tested yet.
*/
/*
* Portions of this code were derived from mod_auth_kerb and Heimdal.
* These packages are available from:
*
* http://modauthkerb.sourceforge.net/
* http://www.pdc.kth.se/heimdal/
*
* and were released under the following licenses:
*
* ----------------------------------------------------------------
*
* Copyright (c) 2004 Masarykova universita
* (Masaryk University, Brno, Czech Republic)
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the University nor the names of its contributors may
* be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* ----------------------------------------------------------------
*
* Copyright (c) 1997 - 2003 Kungliga Tekniska H�gskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* XXXSRA We should omit this file entirely in Makefile.in via autoconf,
* but this will keep it from generating errors until that's written.
*/
#ifdef GSSAPI
/*
* XXXSRA Some of the following files are almost certainly unnecessary,
* but using this list (borrowed from gssapictx.c) gets rid of some
* whacky compilation errors when building with MSVC and should be
* harmless in any case.
*/
#include <config.h>
#include <stdlib.h>
#include <errno.h>
#include <isc/buffer.h>
#include <isc/dir.h>
#include <isc/entropy.h>
#include <isc/lex.h>
#include <isc/mem.h>
#include <isc/once.h>
#include <isc/random.h>
#include <isc/string.h>
#include <isc/time.h>
#include <isc/util.h>
#include <dns/fixedname.h>
#include <dns/name.h>
#include <dns/rdata.h>
#include <dns/rdataclass.h>
#include <dns/result.h>
#include <dns/types.h>
#include <dns/keyvalues.h>
#include <dns/log.h>
#include <dst/gssapi.h>
#include <dst/result.h>
#include "dst_internal.h"
/*
* The API we export
*/
#include "spnego.h"
/* asn1_err.h */
/* Generated from ../../../lib/asn1/asn1_err.et */
typedef enum asn1_error_number {
ASN1_BAD_TIMEFORMAT = 1859794432,
ASN1_MISSING_FIELD = 1859794433,
ASN1_MISPLACED_FIELD = 1859794434,
ASN1_TYPE_MISMATCH = 1859794435,
ASN1_OVERFLOW = 1859794436,
ASN1_OVERRUN = 1859794437,
ASN1_BAD_ID = 1859794438,
ASN1_BAD_LENGTH = 1859794439,
ASN1_BAD_FORMAT = 1859794440,
ASN1_PARSE_ERROR = 1859794441
} asn1_error_number;
#define ERROR_TABLE_BASE_asn1 1859794432
#define __asn1_common_definitions__
typedef struct octet_string {
size_t length;
void *data;
} octet_string;
typedef char *general_string;
typedef char *utf8_string;
typedef struct oid {
size_t length;
unsigned *components;
} oid;
/* der.h */
typedef enum {
ASN1_C_UNIV = 0, ASN1_C_APPL = 1,
ASN1_C_CONTEXT = 2, ASN1_C_PRIVATE = 3
} Der_class;
typedef enum {
PRIM = 0, CONS = 1
} Der_type;
/* Universal tags */
enum {
UT_Boolean = 1,
UT_Integer = 2,
UT_BitString = 3,
UT_OctetString = 4,
UT_Null = 5,
UT_OID = 6,
UT_Enumerated = 10,
UT_Sequence = 16,
UT_Set = 17,
UT_PrintableString = 19,
UT_IA5String = 22,
UT_UTCTime = 23,
UT_GeneralizedTime = 24,
UT_VisibleString = 26,
UT_GeneralString = 27
};
#define ASN1_INDEFINITE 0xdce0deed
static int
der_get_length(const unsigned char *p, size_t len,
size_t * val, size_t * size);
static int
der_get_octet_string(const unsigned char *p, size_t len,
octet_string * data, size_t * size);
static int
der_get_oid(const unsigned char *p, size_t len,
oid * data, size_t * size);
static int
der_get_tag(const unsigned char *p, size_t len,
Der_class * class, Der_type * type,
int *tag, size_t * size);
static int
der_match_tag(const unsigned char *p, size_t len,
Der_class class, Der_type type,
int tag, size_t * size);
static int
der_match_tag_and_length(const unsigned char *p, size_t len,
Der_class class, Der_type type, int tag,
size_t * length_ret, size_t * size);
static int
decode_oid(const unsigned char *p, size_t len,
oid * k, size_t * size);
static int
decode_enumerated(const unsigned char *p, size_t len,
unsigned *num, size_t *size);
static int
decode_octet_string(const unsigned char *, size_t, octet_string *, size_t *);
static int
der_put_int(unsigned char *p, size_t len, int val, size_t *);
static int
der_put_length(unsigned char *p, size_t len, size_t val, size_t *);
static int
der_put_octet_string(unsigned char *p, size_t len,
const octet_string * data, size_t *);
static int
der_put_oid(unsigned char *p, size_t len,
const oid * data, size_t * size);
static int
der_put_tag(unsigned char *p, size_t len, Der_class class, Der_type type,
int tag, size_t *);
static int
der_put_length_and_tag(unsigned char *, size_t, size_t,
Der_class, Der_type, int, size_t *);
static int
encode_enumerated(unsigned char *p, size_t len,
const unsigned *data, size_t *);
static int
encode_octet_string(unsigned char *p, size_t len,
const octet_string * k, size_t *);
static int
encode_oid(unsigned char *p, size_t len,
const oid * k, size_t *);
static void
free_octet_string(octet_string * k);
static void
free_oid (oid * k);
static size_t
length_len(size_t len);
static int
fix_dce(size_t reallen, size_t * len);
/*
* Include stuff generated by the ASN.1 compiler.
*/
#include "spnego_asn1.c"
static unsigned char gss_krb5_mech_oid_bytes[] = {
0x2a, 0x86, 0x48, 0x86, 0xf7, 0x12, 0x01, 0x02, 0x02
};
static gss_OID_desc gss_krb5_mech_oid_desc = {
sizeof(gss_krb5_mech_oid_bytes),
gss_krb5_mech_oid_bytes
};
static gss_OID GSS_KRB5_MECH = &gss_krb5_mech_oid_desc;
static unsigned char gss_mskrb5_mech_oid_bytes[] = {
0x2a, 0x86, 0x48, 0x82, 0xf7, 0x12, 0x01, 0x02, 0x02
};
static gss_OID_desc gss_mskrb5_mech_oid_desc = {
sizeof(gss_mskrb5_mech_oid_bytes),
gss_mskrb5_mech_oid_bytes
};
static gss_OID GSS_MSKRB5_MECH = &gss_mskrb5_mech_oid_desc;
static unsigned char gss_spnego_mech_oid_bytes[] = {
0x2b, 0x06, 0x01, 0x05, 0x05, 0x02
};
static gss_OID_desc gss_spnego_mech_oid_desc = {
sizeof(gss_spnego_mech_oid_bytes),
gss_spnego_mech_oid_bytes
};
static gss_OID GSS_SPNEGO_MECH = &gss_spnego_mech_oid_desc;
/* spnegokrb5_locl.h */
static OM_uint32
gssapi_spnego_encapsulate(OM_uint32 *,
unsigned char *,
size_t,
gss_buffer_t,
const gss_OID);
static OM_uint32
gssapi_spnego_decapsulate(OM_uint32 *,
gss_buffer_t,
unsigned char **,
size_t *,
const gss_OID);
/* mod_auth_kerb.c */
static int
cmp_gss_type(gss_buffer_t token, gss_OID oid)
{
unsigned char *p;
size_t len;
if (token->length == 0)
return (GSS_S_DEFECTIVE_TOKEN);
p = token->value;
if (*p++ != 0x60)
return (GSS_S_DEFECTIVE_TOKEN);
len = *p++;
if (len & 0x80) {
if ((len & 0x7f) > 4)
return (GSS_S_DEFECTIVE_TOKEN);
p += len & 0x7f;
}
if (*p++ != 0x06)
return (GSS_S_DEFECTIVE_TOKEN);
if (((OM_uint32) *p++) != oid->length)
return (GSS_S_DEFECTIVE_TOKEN);
return (memcmp(p, oid->elements, oid->length));
}
/* accept_sec_context.c */
/*
* SPNEGO wrapper for Kerberos5 GSS-API kouril@ics.muni.cz, 2003 (mostly
* based on Heimdal code)
*/
static OM_uint32
code_NegTokenArg(OM_uint32 * minor_status,
const NegTokenResp * resp,
unsigned char **outbuf,
size_t * outbuf_size)
{
OM_uint32 ret;
u_char *buf;
size_t buf_size, buf_len;
buf_size = 1024;
buf = malloc(buf_size);
if (buf == NULL) {
*minor_status = ENOMEM;
return (GSS_S_FAILURE);
}
do {
ret = encode_NegTokenResp(buf + buf_size - 1,
buf_size,
resp, &buf_len);
if (ret == 0) {
size_t tmp;
ret = der_put_length_and_tag(buf + buf_size - buf_len - 1,
buf_size - buf_len,
buf_len,
ASN1_C_CONTEXT,
CONS,
1,
&tmp);
if (ret == 0)
buf_len += tmp;
}
if (ret) {
if (ret == ASN1_OVERFLOW) {
u_char *tmp;
buf_size *= 2;
tmp = realloc(buf, buf_size);
if (tmp == NULL) {
*minor_status = ENOMEM;
free(buf);
return (GSS_S_FAILURE);
}
buf = tmp;
} else {
*minor_status = ret;
free(buf);
return (GSS_S_FAILURE);
}
}
} while (ret == ASN1_OVERFLOW);
*outbuf = malloc(buf_len);
if (*outbuf == NULL) {
*minor_status = ENOMEM;
free(buf);
return (GSS_S_FAILURE);
}
memcpy(*outbuf, buf + buf_size - buf_len, buf_len);
*outbuf_size = buf_len;
free(buf);
return (GSS_S_COMPLETE);
}
static OM_uint32
send_reject(OM_uint32 * minor_status,
gss_buffer_t output_token)
{
NegTokenResp resp;
OM_uint32 ret;
resp.negState = malloc(sizeof(*resp.negState));
if (resp.negState == NULL) {
*minor_status = ENOMEM;
return (GSS_S_FAILURE);
}
*(resp.negState) = reject;
resp.supportedMech = NULL;
resp.responseToken = NULL;
resp.mechListMIC = NULL;
ret = code_NegTokenArg(minor_status, &resp,
(unsigned char **)&output_token->value,
&output_token->length);
free_NegTokenResp(&resp);
if (ret)
return (ret);
return (GSS_S_BAD_MECH);
}
static OM_uint32
send_accept(OM_uint32 * minor_status,
gss_buffer_t output_token,
gss_buffer_t mech_token,
const gss_OID pref)
{
NegTokenResp resp;
OM_uint32 ret;
memset(&resp, 0, sizeof(resp));
resp.negState = malloc(sizeof(*resp.negState));
if (resp.negState == NULL) {
*minor_status = ENOMEM;
return (GSS_S_FAILURE);
}
*(resp.negState) = accept_completed;
resp.supportedMech = malloc(sizeof(*resp.supportedMech));
if (resp.supportedMech == NULL) {
free_NegTokenResp(&resp);
*minor_status = ENOMEM;
return (GSS_S_FAILURE);
}
ret = der_get_oid(pref->elements,
pref->length,
resp.supportedMech,
NULL);
if (ret) {
free_NegTokenResp(&resp);
*minor_status = ENOMEM;
return (GSS_S_FAILURE);
}
if (mech_token != NULL && mech_token->length != 0) {
resp.responseToken = malloc(sizeof(*resp.responseToken));
if (resp.responseToken == NULL) {
free_NegTokenResp(&resp);
*minor_status = ENOMEM;
return (GSS_S_FAILURE);
}
resp.responseToken->length = mech_token->length;
resp.responseToken->data = mech_token->value;
}
ret = code_NegTokenArg(minor_status, &resp,
(unsigned char **)&output_token->value,
&output_token->length);
if (resp.responseToken != NULL) {
free(resp.responseToken);
resp.responseToken = NULL;
}
free_NegTokenResp(&resp);
if (ret)
return (ret);
return (GSS_S_COMPLETE);
}
OM_uint32
gss_accept_sec_context_spnego(OM_uint32 *minor_status,
gss_ctx_id_t *context_handle,
const gss_cred_id_t acceptor_cred_handle,
const gss_buffer_t input_token_buffer,
const gss_channel_bindings_t input_chan_bindings,
gss_name_t *src_name,
gss_OID *mech_type,
gss_buffer_t output_token,
OM_uint32 *ret_flags,
OM_uint32 *time_rec,
gss_cred_id_t *delegated_cred_handle)
{
NegTokenInit init_token;
OM_uint32 major_status;
OM_uint32 minor_status2;
gss_buffer_desc ibuf, obuf;
gss_buffer_t ot = NULL;
gss_OID pref = GSS_KRB5_MECH;
unsigned char *buf;
size_t buf_size;
size_t len, taglen, ni_len;
int found = 0;
int ret;
unsigned i;
/*
* Before doing anything else, see whether this is a SPNEGO
* PDU. If not, dispatch to the GSSAPI library and get out.
*/
if (cmp_gss_type(input_token_buffer, GSS_SPNEGO_MECH))
return (gss_accept_sec_context(minor_status,
context_handle,
acceptor_cred_handle,
input_token_buffer,
input_chan_bindings,
src_name,
mech_type,
output_token,
ret_flags,
time_rec,
delegated_cred_handle));
/*
* If we get here, it's SPNEGO.
*/
memset(&init_token, 0, sizeof(init_token));
ret = gssapi_spnego_decapsulate(minor_status, input_token_buffer,
&buf, &buf_size, GSS_SPNEGO_MECH);
if (ret)
return (ret);
ret = der_match_tag_and_length(buf, buf_size, ASN1_C_CONTEXT, CONS,
0, &len, &taglen);
if (ret)
return (ret);
ret = decode_NegTokenInit(buf + taglen, len, &init_token, &ni_len);
if (ret) {
*minor_status = EINVAL; /* XXX */
return (GSS_S_DEFECTIVE_TOKEN);
}
for (i = 0; !found && i < init_token.mechTypes.len; ++i) {
char mechbuf[17];
size_t mech_len;
ret = der_put_oid(mechbuf + sizeof(mechbuf) - 1,
sizeof(mechbuf),
&init_token.mechTypes.val[i],
&mech_len);
if (ret)
return (GSS_S_DEFECTIVE_TOKEN);
if (mech_len == GSS_KRB5_MECH->length &&
memcmp(GSS_KRB5_MECH->elements,
mechbuf + sizeof(mechbuf) - mech_len,
mech_len) == 0) {
found = 1;
break;
}
if (mech_len == GSS_MSKRB5_MECH->length &&
memcmp(GSS_MSKRB5_MECH->elements,
mechbuf + sizeof(mechbuf) - mech_len,
mech_len) == 0) {
found = 1;
if (i == 0)
pref = GSS_MSKRB5_MECH;
break;
}
}
if (!found)
return (send_reject(minor_status, output_token));
if (i == 0 && init_token.mechToken != NULL) {
ibuf.length = init_token.mechToken->length;
ibuf.value = init_token.mechToken->data;
major_status = gss_accept_sec_context(minor_status,
context_handle,
acceptor_cred_handle,
&ibuf,
input_chan_bindings,
src_name,
mech_type,
&obuf,
ret_flags,
time_rec,
delegated_cred_handle);
if (GSS_ERROR(major_status)) {
send_reject(&minor_status2, output_token);
return (major_status);
}
ot = &obuf;
}
ret = send_accept(&minor_status2, output_token, ot, pref);
if (ot != NULL && ot->length != 0)
gss_release_buffer(&minor_status2, ot);
return (ret);
}
/* decapsulate.c */
static OM_uint32
gssapi_verify_mech_header(u_char ** str,
size_t total_len,
const gss_OID mech)
{
size_t len, len_len, mech_len, foo;
int e;
u_char *p = *str;
if (total_len < 1)
return (GSS_S_DEFECTIVE_TOKEN);
if (*p++ != 0x60)
return (GSS_S_DEFECTIVE_TOKEN);
e = der_get_length(p, total_len - 1, &len, &len_len);
if (e || 1 + len_len + len != total_len)
return (GSS_S_DEFECTIVE_TOKEN);
p += len_len;
if (*p++ != 0x06)
return (GSS_S_DEFECTIVE_TOKEN);
e = der_get_length(p, total_len - 1 - len_len - 1,
&mech_len, &foo);
if (e)
return (GSS_S_DEFECTIVE_TOKEN);
p += foo;
if (mech_len != mech->length)
return (GSS_S_BAD_MECH);
if (memcmp(p, mech->elements, mech->length) != 0)
return (GSS_S_BAD_MECH);
p += mech_len;
*str = p;
return (GSS_S_COMPLETE);
}
/*
* Remove the GSS-API wrapping from `in_token' giving `buf and buf_size' Does
* not copy data, so just free `in_token'.
*/
static OM_uint32
gssapi_spnego_decapsulate(OM_uint32 *minor_status,
gss_buffer_t input_token_buffer,
unsigned char **buf,
size_t *buf_len,
const gss_OID mech)
{
u_char *p;
OM_uint32 ret;
p = input_token_buffer->value;
ret = gssapi_verify_mech_header(&p,
input_token_buffer->length,
mech);
if (ret) {
*minor_status = ret;
return (GSS_S_FAILURE);
}
*buf_len = input_token_buffer->length -
(p - (u_char *) input_token_buffer->value);
*buf = p;
return (GSS_S_COMPLETE);
}
/* der_free.c */
static void
free_octet_string(octet_string *k)
{
free(k->data);
k->data = NULL;
}
static void
free_oid(oid *k)
{
free(k->components);
k->components = NULL;
}
/* der_get.c */
/*
* All decoding functions take a pointer `p' to first position in which to
* read, from the left, `len' which means the maximum number of characters we
* are able to read, `ret' were the value will be returned and `size' where
* the number of used bytes is stored. Either 0 or an error code is returned.
*/
static int
der_get_unsigned(const unsigned char *p, size_t len,
unsigned *ret, size_t *size)
{
unsigned val = 0;
size_t oldlen = len;
while (len--)
val = val * 256 + *p++;
*ret = val;
if (size)
*size = oldlen;
return (0);
}
static int
der_get_int(const unsigned char *p, size_t len,
int *ret, size_t *size)
{
int val = 0;
size_t oldlen = len;
if (len > 0) {
val = (signed char)*p++;
while (--len)
val = val * 256 + *p++;
}
*ret = val;
if (size)
*size = oldlen;
return (0);
}
static int
der_get_length(const unsigned char *p, size_t len,
size_t *val, size_t *size)
{
size_t v;
if (len <= 0)
return (ASN1_OVERRUN);
--len;
v = *p++;
if (v < 128) {
*val = v;
if (size)
*size = 1;
} else {
int e;
size_t l;
unsigned tmp;
if (v == 0x80) {
*val = ASN1_INDEFINITE;
if (size)
*size = 1;
return (0);
}
v &= 0x7F;
if (len < v)
return (ASN1_OVERRUN);
e = der_get_unsigned(p, v, &tmp, &l);
if (e)
return (e);
*val = tmp;
if (size)
*size = l + 1;
}
return (0);
}
static int
der_get_octet_string(const unsigned char *p, size_t len,
octet_string *data, size_t *size)
{
data->length = len;
data->data = malloc(len);
if (data->data == NULL && data->length != 0)
return (ENOMEM);
memcpy(data->data, p, len);
if (size)
*size = len;
return (0);
}
static int
der_get_oid(const unsigned char *p, size_t len,
oid *data, size_t *size)
{
int n;
size_t oldlen = len;
if (len < 1)
return (ASN1_OVERRUN);
data->components = malloc(len * sizeof(*data->components));
if (data->components == NULL && len != 0)
return (ENOMEM);
data->components[0] = (*p) / 40;
data->components[1] = (*p) % 40;
--len;
++p;
for (n = 2; len > 0; ++n) {
unsigned u = 0;
do {
--len;
u = u * 128 + (*p++ % 128);
} while (len > 0 && p[-1] & 0x80);
data->components[n] = u;
}
if (p[-1] & 0x80) {
free_oid(data);
return (ASN1_OVERRUN);
}
data->length = n;
if (size)
*size = oldlen;
return (0);
}
static int
der_get_tag(const unsigned char *p, size_t len,
Der_class *class, Der_type *type,
int *tag, size_t *size)
{
if (len < 1)
return (ASN1_OVERRUN);
*class = (Der_class) (((*p) >> 6) & 0x03);
*type = (Der_type) (((*p) >> 5) & 0x01);
*tag = (*p) & 0x1F;
if (size)
*size = 1;
return (0);
}
static int
der_match_tag(const unsigned char *p, size_t len,
Der_class class, Der_type type,
int tag, size_t *size)
{
size_t l;
Der_class thisclass;
Der_type thistype;
int thistag;
int e;
e = der_get_tag(p, len, &thisclass, &thistype, &thistag, &l);
if (e)
return (e);
if (class != thisclass || type != thistype)
return (ASN1_BAD_ID);
if (tag > thistag)
return (ASN1_MISPLACED_FIELD);
if (tag < thistag)
return (ASN1_MISSING_FIELD);
if (size)
*size = l;
return (0);
}
static int
der_match_tag_and_length(const unsigned char *p, size_t len,
Der_class class, Der_type type, int tag,
size_t *length_ret, size_t *size)
{
size_t l, ret = 0;
int e;
e = der_match_tag(p, len, class, type, tag, &l);
if (e)
return (e);
p += l;
len -= l;
ret += l;
e = der_get_length(p, len, length_ret, &l);
if (e)
return (e);
p += l;
len -= l;
ret += l;
if (size)
*size = ret;
return (0);
}
static int
decode_enumerated(const unsigned char *p, size_t len,
unsigned *num, size_t *size)
{
size_t ret = 0;
size_t l, reallen;
int e;
e = der_match_tag(p, len, ASN1_C_UNIV, PRIM, UT_Enumerated, &l);
if (e)
return (e);
p += l;
len -= l;
ret += l;
e = der_get_length(p, len, &reallen, &l);
if (e)
return (e);
p += l;
len -= l;
ret += l;
e = der_get_int(p, reallen, num, &l);
if (e)
return (e);
p += l;
len -= l;
ret += l;
if (size)
*size = ret;
return (0);
}
static int
decode_octet_string(const unsigned char *p, size_t len,
octet_string *k, size_t *size)
{
size_t ret = 0;
size_t l;
int e;
size_t slen;
e = der_match_tag(p, len, ASN1_C_UNIV, PRIM, UT_OctetString, &l);
if (e)
return (e);
p += l;
len -= l;
ret += l;
e = der_get_length(p, len, &slen, &l);
if (e)
return (e);
p += l;
len -= l;
ret += l;
if (len < slen)
return (ASN1_OVERRUN);
e = der_get_octet_string(p, slen, k, &l);
if (e)
return (e);
p += l;
len -= l;
ret += l;
if (size)
*size = ret;
return (0);
}
static int
decode_oid(const unsigned char *p, size_t len,
oid *k, size_t *size)
{
size_t ret = 0;
size_t l;
int e;
size_t slen;
e = der_match_tag(p, len, ASN1_C_UNIV, PRIM, UT_OID, &l);
if (e)
return (e);
p += l;
len -= l;
ret += l;
e = der_get_length(p, len, &slen, &l);
if (e)
return (e);
p += l;
len -= l;
ret += l;
if (len < slen)
return (ASN1_OVERRUN);
e = der_get_oid(p, slen, k, &l);
if (e)
return (e);
p += l;
len -= l;
ret += l;
if (size)
*size = ret;
return (0);
}
static int
fix_dce(size_t reallen, size_t *len)
{
if (reallen == ASN1_INDEFINITE)
return (1);
if (*len < reallen)
return (-1);
*len = reallen;
return (0);
}
/* der_length.c */
static size_t
len_unsigned(unsigned val)
{
size_t ret = 0;
do {
++ret;
val /= 256;
} while (val);
return (ret);
}
static size_t
length_len(size_t len)
{
if (len < 128)
return (1);
else
return (len_unsigned(len) + 1);
}
/* der_put.c */
/*
* All encoding functions take a pointer `p' to first position in which to
* write, from the right, `len' which means the maximum number of characters
* we are able to write. The function returns the number of characters
* written in `size' (if non-NULL). The return value is 0 or an error.
*/
static int
der_put_unsigned(unsigned char *p, size_t len, unsigned val, size_t *size)
{
unsigned char *base = p;
if (val) {
while (len > 0 && val) {
*p-- = val % 256;
val /= 256;
--len;
}
if (val != 0)
return (ASN1_OVERFLOW);
else {
*size = base - p;
return (0);
}
} else if (len < 1)
return (ASN1_OVERFLOW);
else {
*p = 0;
*size = 1;
return (0);
}
}
static int
der_put_int(unsigned char *p, size_t len, int val, size_t *size)
{
unsigned char *base = p;
if (val >= 0) {
do {
if (len < 1)
return (ASN1_OVERFLOW);
*p-- = val % 256;
len--;
val /= 256;
} while (val);
if (p[1] >= 128) {
if (len < 1)
return (ASN1_OVERFLOW);
*p-- = 0;
len--;
}
} else {
val = ~val;
do {
if (len < 1)
return (ASN1_OVERFLOW);
*p-- = ~(val % 256);
len--;
val /= 256;
} while (val);
if (p[1] < 128) {
if (len < 1)
return (ASN1_OVERFLOW);
*p-- = 0xff;
len--;
}
}
*size = base - p;
return (0);
}
static int
der_put_length(unsigned char *p, size_t len, size_t val, size_t *size)
{
if (len < 1)
return (ASN1_OVERFLOW);
if (val < 128) {
*p = val;
*size = 1;
return (0);
} else {
size_t l;
int e;
e = der_put_unsigned(p, len - 1, val, &l);
if (e)
return (e);
p -= l;
*p = 0x80 | l;
*size = l + 1;
return (0);
}
}
static int
der_put_octet_string(unsigned char *p, size_t len,
const octet_string *data, size_t *size)
{
if (len < data->length)
return (ASN1_OVERFLOW);
p -= data->length;
len -= data->length;
memcpy(p + 1, data->data, data->length);
*size = data->length;
return (0);
}
static int
der_put_oid(unsigned char *p, size_t len,
const oid *data, size_t *size)
{
unsigned char *base = p;
int n;
for (n = data->length - 1; n >= 2; --n) {
unsigned u = data->components[n];
if (len < 1)
return (ASN1_OVERFLOW);
*p-- = u % 128;
u /= 128;
--len;
while (u > 0) {
if (len < 1)
return (ASN1_OVERFLOW);
*p-- = 128 + u % 128;
u /= 128;
--len;
}
}
if (len < 1)
return (ASN1_OVERFLOW);
*p-- = 40 * data->components[0] + data->components[1];
*size = base - p;
return (0);
}
static int
der_put_tag(unsigned char *p, size_t len, Der_class class, Der_type type,
int tag, size_t *size)
{
if (len < 1)
return (ASN1_OVERFLOW);
*p = (class << 6) | (type << 5) | tag; /* XXX */
*size = 1;
return (0);
}
static int
der_put_length_and_tag(unsigned char *p, size_t len, size_t len_val,
Der_class class, Der_type type, int tag, size_t *size)
{
size_t ret = 0;
size_t l;
int e;
e = der_put_length(p, len, len_val, &l);
if (e)
return (e);
p -= l;
len -= l;
ret += l;
e = der_put_tag(p, len, class, type, tag, &l);
if (e)
return (e);
p -= l;
len -= l;
ret += l;
*size = ret;
return (0);
}
static int
encode_enumerated(unsigned char *p, size_t len, const unsigned *data,
size_t *size)
{
unsigned num = *data;
size_t ret = 0;
size_t l;
int e;
e = der_put_int(p, len, num, &l);
if (e)
return (e);
p -= l;
len -= l;
ret += l;
e = der_put_length_and_tag(p, len, l, ASN1_C_UNIV, PRIM, UT_Enumerated, &l);
if (e)
return (e);
p -= l;
len -= l;
ret += l;
*size = ret;
return (0);
}
static int
encode_octet_string(unsigned char *p, size_t len,
const octet_string *k, size_t *size)
{
size_t ret = 0;
size_t l;
int e;
e = der_put_octet_string(p, len, k, &l);
if (e)
return (e);
p -= l;
len -= l;
ret += l;
e = der_put_length_and_tag(p, len, l, ASN1_C_UNIV, PRIM, UT_OctetString, &l);
if (e)
return (e);
p -= l;
len -= l;
ret += l;
*size = ret;
return (0);
}
static int
encode_oid(unsigned char *p, size_t len,
const oid *k, size_t *size)
{
size_t ret = 0;
size_t l;
int e;
e = der_put_oid(p, len, k, &l);
if (e)
return (e);
p -= l;
len -= l;
ret += l;
e = der_put_length_and_tag(p, len, l, ASN1_C_UNIV, PRIM, UT_OID, &l);
if (e)
return (e);
p -= l;
len -= l;
ret += l;
*size = ret;
return (0);
}
/* encapsulate.c */
static void
gssapi_encap_length(size_t data_len,
size_t *len,
size_t *total_len,
const gss_OID mech)
{
size_t len_len;
*len = 1 + 1 + mech->length + data_len;
len_len = length_len(*len);
*total_len = 1 + len_len + *len;
}
static u_char *
gssapi_mech_make_header(u_char *p,
size_t len,
const gss_OID mech)
{
int e;
size_t len_len, foo;
*p++ = 0x60;
len_len = length_len(len);
e = der_put_length(p + len_len - 1, len_len, len, &foo);
if (e || foo != len_len)
return (NULL);
p += len_len;
*p++ = 0x06;
*p++ = mech->length;
memcpy(p, mech->elements, mech->length);
p += mech->length;
return (p);
}
/*
* Give it a krb5_data and it will encapsulate with extra GSS-API wrappings.
*/
static OM_uint32
gssapi_spnego_encapsulate(OM_uint32 * minor_status,
unsigned char *buf,
size_t buf_size,
gss_buffer_t output_token,
const gss_OID mech)
{
size_t len, outer_len;
u_char *p;
gssapi_encap_length(buf_size, &len, &outer_len, mech);
output_token->length = outer_len;
output_token->value = malloc(outer_len);
if (output_token->value == NULL) {
*minor_status = ENOMEM;
return (GSS_S_FAILURE);
}
p = gssapi_mech_make_header(output_token->value, len, mech);
if (p == NULL) {
if (output_token->length != 0)
gss_release_buffer(minor_status, output_token);
return (GSS_S_FAILURE);
}
memcpy(p, buf, buf_size);
return (GSS_S_COMPLETE);
}
/* init_sec_context.c */
/*
* SPNEGO wrapper for Kerberos5 GSS-API kouril@ics.muni.cz, 2003 (mostly
* based on Heimdal code)
*/
static int
add_mech(MechTypeList * mech_list, gss_OID mech)
{
MechType *tmp;
int ret;
tmp = realloc(mech_list->val, (mech_list->len + 1) * sizeof(*tmp));
if (tmp == NULL)
return (ENOMEM);
mech_list->val = tmp;
ret = der_get_oid(mech->elements, mech->length,
&mech_list->val[mech_list->len], NULL);
if (ret)
return (ret);
mech_list->len++;
return (0);
}
/*
* return the length of the mechanism in token or -1
* (which implies that the token was bad - GSS_S_DEFECTIVE_TOKEN
*/
static ssize_t
gssapi_krb5_get_mech(const u_char *ptr,
size_t total_len,
const u_char **mech_ret)
{
size_t len, len_len, mech_len, foo;
const u_char *p = ptr;
int e;
if (total_len < 1)
return (-1);
if (*p++ != 0x60)
return (-1);
e = der_get_length (p, total_len - 1, &len, &len_len);
if (e || 1 + len_len + len != total_len)
return (-1);
p += len_len;
if (*p++ != 0x06)
return (-1);
e = der_get_length (p, total_len - 1 - len_len - 1,
&mech_len, &foo);
if (e)
return (-1);
p += foo;
*mech_ret = p;
return (mech_len);
}
static OM_uint32
spnego_initial(OM_uint32 *minor_status,
const gss_cred_id_t initiator_cred_handle,
gss_ctx_id_t *context_handle,
const gss_name_t target_name,
const gss_OID mech_type,
OM_uint32 req_flags,
OM_uint32 time_req,
const gss_channel_bindings_t input_chan_bindings,
const gss_buffer_t input_token,
gss_OID *actual_mech_type,
gss_buffer_t output_token,
OM_uint32 *ret_flags,
OM_uint32 *time_rec)
{
NegTokenInit token_init;
OM_uint32 major_status, minor_status2;
gss_buffer_desc krb5_output_token = GSS_C_EMPTY_BUFFER;
unsigned char *buf = NULL;
size_t buf_size;
size_t len;
int ret;
(void)mech_type;
memset(&token_init, 0, sizeof(token_init));
ret = add_mech(&token_init.mechTypes, GSS_KRB5_MECH);
if (ret) {
*minor_status = ret;
ret = GSS_S_FAILURE;
goto end;
}
major_status = gss_init_sec_context(minor_status,
initiator_cred_handle,
context_handle,
target_name,
GSS_KRB5_MECH,
req_flags,
time_req,
input_chan_bindings,
input_token,
actual_mech_type,
&krb5_output_token,
ret_flags,
time_rec);
if (GSS_ERROR(major_status)) {
ret = major_status;
goto end;
}
if (krb5_output_token.length > 0) {
token_init.mechToken = malloc(sizeof(*token_init.mechToken));
if (token_init.mechToken == NULL) {
*minor_status = ENOMEM;
ret = GSS_S_FAILURE;
goto end;
}
token_init.mechToken->data = krb5_output_token.value;
token_init.mechToken->length = krb5_output_token.length;
}
/*
* The MS implementation of SPNEGO seems to not like the mechListMIC
* field, so we omit it (it's optional anyway)
*/
buf_size = 1024;
buf = malloc(buf_size);
do {
ret = encode_NegTokenInit(buf + buf_size - 1,
buf_size,
&token_init, &len);
if (ret == 0) {
size_t tmp;
ret = der_put_length_and_tag(buf + buf_size - len - 1,
buf_size - len,
len,
ASN1_C_CONTEXT,
CONS,
0,
&tmp);
if (ret == 0)
len += tmp;
}
if (ret) {
if (ret == ASN1_OVERFLOW) {
u_char *tmp;
buf_size *= 2;
tmp = realloc(buf, buf_size);
if (tmp == NULL) {
*minor_status = ENOMEM;
ret = GSS_S_FAILURE;
goto end;
}
buf = tmp;
} else {
*minor_status = ret;
ret = GSS_S_FAILURE;
goto end;
}
}
} while (ret == ASN1_OVERFLOW);
ret = gssapi_spnego_encapsulate(minor_status,
buf + buf_size - len, len,
output_token, GSS_SPNEGO_MECH);
if (ret == GSS_S_COMPLETE)
ret = major_status;
end:
if (token_init.mechToken != NULL) {
free(token_init.mechToken);
token_init.mechToken = NULL;
}
free_NegTokenInit(&token_init);
if (krb5_output_token.length != 0)
gss_release_buffer(&minor_status2, &krb5_output_token);
if (buf)
free(buf);
return (ret);
}
static OM_uint32
spnego_reply(OM_uint32 *minor_status,
const gss_cred_id_t initiator_cred_handle,
gss_ctx_id_t *context_handle,
const gss_name_t target_name,
const gss_OID mech_type,
OM_uint32 req_flags,
OM_uint32 time_req,
const gss_channel_bindings_t input_chan_bindings,
const gss_buffer_t input_token,
gss_OID *actual_mech_type,
gss_buffer_t output_token,
OM_uint32 *ret_flags,
OM_uint32 *time_rec)
{
OM_uint32 ret;
NegTokenResp resp;
unsigned char *buf;
size_t buf_size;
u_char oidbuf[17];
size_t oidlen;
gss_buffer_desc sub_token;
ssize_t mech_len;
const u_char *p;
size_t len, taglen;
(void)mech_type;
output_token->length = 0;
output_token->value = NULL;
/*
* SPNEGO doesn't include gss wrapping on SubsequentContextToken
* like the Kerberos 5 mech does. But lets check for it anyway.
*/
mech_len = gssapi_krb5_get_mech(input_token->value,
input_token->length,
&p);
if (mech_len < 0) {
buf = input_token->value;
buf_size = input_token->length;
} else if ((size_t)mech_len == GSS_KRB5_MECH->length &&
memcmp(GSS_KRB5_MECH->elements, p, mech_len) == 0)
return (gss_init_sec_context(minor_status,
initiator_cred_handle,
context_handle,
target_name,
GSS_KRB5_MECH,
req_flags,
time_req,
input_chan_bindings,
input_token,
actual_mech_type,
output_token,
ret_flags,
time_rec));
else if ((size_t)mech_len == GSS_SPNEGO_MECH->length &&
memcmp(GSS_SPNEGO_MECH->elements, p, mech_len) == 0) {
ret = gssapi_spnego_decapsulate(minor_status,
input_token,
&buf,
&buf_size,
GSS_SPNEGO_MECH);
if (ret)
return (ret);
} else
return (GSS_S_BAD_MECH);
ret = der_match_tag_and_length(buf, buf_size,
ASN1_C_CONTEXT, CONS, 1, &len, &taglen);
if (ret)
return (ret);
if(len > buf_size - taglen)
return (ASN1_OVERRUN);
ret = decode_NegTokenResp(buf + taglen, len, &resp, NULL);
if (ret) {
*minor_status = ENOMEM;
return (GSS_S_FAILURE);
}
if (resp.negState == NULL ||
*(resp.negState) == reject ||
resp.supportedMech == NULL) {
free_NegTokenResp(&resp);
return (GSS_S_BAD_MECH);
}
ret = der_put_oid(oidbuf + sizeof(oidbuf) - 1,
sizeof(oidbuf),
resp.supportedMech,
&oidlen);
if (ret || oidlen != GSS_KRB5_MECH->length ||
memcmp(oidbuf + sizeof(oidbuf) - oidlen,
GSS_KRB5_MECH->elements,
oidlen) != 0) {
free_NegTokenResp(&resp);
return GSS_S_BAD_MECH;
}
if (resp.responseToken != NULL) {
sub_token.length = resp.responseToken->length;
sub_token.value = resp.responseToken->data;
} else {
sub_token.length = 0;
sub_token.value = NULL;
}
ret = gss_init_sec_context(minor_status,
initiator_cred_handle,
context_handle,
target_name,
GSS_KRB5_MECH,
req_flags,
time_req,
input_chan_bindings,
&sub_token,
actual_mech_type,
output_token,
ret_flags,
time_rec);
if (ret) {
free_NegTokenResp(&resp);
return (ret);
}
/*
* XXXSRA I don't think this limited implementation ever needs
* to check the MIC -- our preferred mechanism (Kerberos)
* authenticates its own messages and is the only mechanism
* we'll accept, so if the mechanism negotiation completes
* sucessfully, we don't need the MIC. See RFC 4178.
*/
free_NegTokenResp(&resp);
return (ret);
}
OM_uint32
gss_init_sec_context_spnego(OM_uint32 *minor_status,
const gss_cred_id_t initiator_cred_handle,
gss_ctx_id_t *context_handle,
const gss_name_t target_name,
const gss_OID mech_type,
OM_uint32 req_flags,
OM_uint32 time_req,
const gss_channel_bindings_t input_chan_bindings,
const gss_buffer_t input_token,
gss_OID *actual_mech_type,
gss_buffer_t output_token,
OM_uint32 *ret_flags,
OM_uint32 *time_rec)
{
/* Dirty trick to suppress compiler warnings */
/* Figure out whether we're starting over or processing a reply */
if (input_token == GSS_C_NO_BUFFER || input_token->length == 0)
return (spnego_initial(minor_status,
initiator_cred_handle,
context_handle,
target_name,
mech_type,
req_flags,
time_req,
input_chan_bindings,
input_token,
actual_mech_type,
output_token,
ret_flags,
time_rec));
else
return (spnego_reply(minor_status,
initiator_cred_handle,
context_handle,
target_name,
mech_type,
req_flags,
time_req,
input_chan_bindings,
input_token,
actual_mech_type,
output_token,
ret_flags,
time_rec));
}
#endif /* GSSAPI */