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gss: SAnon - the Simple Anonymous GSS-API mechanism

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Add support for SAnon, a simple key agreement protocol that provides no
authentication of initiator or acceptor using x25519 ECDH key exchange.
See doc/standardization/draft-howard-gss-sanon-xx.txt for a protocol
description.
This commit is contained in:
Luke Howard
2019-12-30 21:07:04 +11:00
committed by Nicolas Williams
parent beda11a079
commit 4a7eb74374
53 changed files with 3634 additions and 29 deletions
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199
lib/gssapi/sanon/negoex.c Normal file
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/*
* Copyright (c) 2019-2020, AuriStor, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - 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.
*
* 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 HOLDER 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.
*
*/
#include "sanon_locl.h"
OM_uint32 GSSAPI_CALLCONV
_gssspi_sanon_query_mechanism_info(OM_uint32 *minor,
gss_const_OID mech_oid,
unsigned char auth_scheme[16])
{
heim_assert(gss_oid_equal(mech_oid, GSS_SANON_X25519_MECHANISM),
"Invalid mechanism OID passed to query_mechanism_info");
*minor = 0;
/* {DEE384FF-1086-4E86-BE78-B94170BFD376} */
memcpy(auth_scheme,
"\xff\x84\xe3\xde\x86\x10\x86\x4e\xbe\x78\xb9\x41\x70\xbf\xd3\x76", 16);
return GSS_S_COMPLETE;
}
OM_uint32
_gss_sanon_inquire_negoex_key(OM_uint32 *minor,
const sanon_ctx sc,
gss_const_OID desired_object,
gss_buffer_set_t *data_set)
{
OM_uint32 major, tmpMinor;
int initiator_key;
uint8_t typebytes[4];
gss_buffer_desc salt, keyvalue = GSS_C_EMPTY_BUFFER, keytype;
if (sc->rfc4121 == GSS_C_NO_CONTEXT) {
*minor = KRB5KRB_AP_ERR_NOKEY;
return GSS_S_UNAVAILABLE;
}
initiator_key = !!(sc->flags & SANON_FLAG_INITIATOR);
if (gss_oid_equal(desired_object, GSS_C_INQ_NEGOEX_VERIFY_KEY))
initiator_key ^= 1;
else if (!gss_oid_equal(desired_object, GSS_C_INQ_NEGOEX_KEY))
return GSS_S_UNAVAILABLE;
if (initiator_key) {
salt.length = sizeof("sanon-x25519-initiator-negoex-key") - 1;
salt.value = "sanon-x25519-initiator-negoex-key";
} else {
salt.length = sizeof("sanon-x25519-acceptor-negoex-key") - 1;
salt.value = "sanon-x25519-acceptor-negoex-key";
}
_gss_mg_encode_le_uint32(KRB5_ENCTYPE_AES128_CTS_HMAC_SHA256_128, typebytes);
keytype.length = sizeof(typebytes);
keytype.value = typebytes;
major = gss_pseudo_random(minor, sc->rfc4121,
GSS_C_PRF_KEY_FULL, &salt,
16, &keyvalue);
if (major == GSS_S_COMPLETE)
major = gss_add_buffer_set_member(minor, &keyvalue, data_set);
if (major == GSS_S_COMPLETE)
major = gss_add_buffer_set_member(minor, &keytype, data_set);
_gss_secure_release_buffer(&tmpMinor, &keyvalue);
return major;
}
static OM_uint32
make_flags_meta_data(OM_uint32 *minor,
OM_uint32 flags,
gss_buffer_t meta_data)
{
uint8_t data[4];
gss_buffer_desc buffer = { sizeof(data), data };
_gss_mg_encode_le_uint32(flags, data);
return _gss_copy_buffer(minor, &buffer, meta_data);
}
OM_uint32 GSSAPI_CALLCONV
_gssspi_sanon_query_meta_data(OM_uint32 *minor,
gss_const_OID mech_oid,
gss_cred_id_t cred_handle,
gss_ctx_id_t *context_handle,
gss_const_name_t targ_name,
OM_uint32 req_flags,
gss_buffer_t meta_data)
{
OM_uint32 major;
int local = (targ_name != GSS_C_NO_NAME);
*minor = 0;
if (local) {
if (!_gss_sanon_available_p(cred_handle, targ_name, req_flags))
return GSS_S_UNAVAILABLE;
/*
* Obscure Windows interoperability hack: use metadata to convey
* RFC4757 extended flags from initiator to acceptor.
*/
req_flags &= (GSS_C_DCE_STYLE | GSS_C_IDENTIFY_FLAG | GSS_C_EXTENDED_ERROR_FLAG);
if (req_flags) {
major = make_flags_meta_data(minor, req_flags, meta_data);
if (major != GSS_S_COMPLETE)
return major;
}
}
return GSS_S_COMPLETE;
}
static OM_uint32
parse_flags_meta_data(OM_uint32 *minor,
gss_const_buffer_t meta_data,
OM_uint32 *flags)
{
*minor = 0;
*flags = 0;
if (meta_data->length == 0)
return GSS_S_COMPLETE;
if (meta_data->length < 4)
return GSS_S_DEFECTIVE_TOKEN;
_gss_mg_decode_le_uint32(meta_data->value, flags);
return GSS_S_COMPLETE;
}
OM_uint32 GSSAPI_CALLCONV
_gssspi_sanon_exchange_meta_data(OM_uint32 *minor,
gss_const_OID mech_oid,
gss_cred_id_t cred_handle,
gss_ctx_id_t *context_handle,
gss_const_name_t targ_name,
OM_uint32 req_flags,
gss_const_buffer_t meta_data)
{
sanon_ctx sc = (sanon_ctx)*context_handle;
int local = (targ_name != GSS_C_NO_NAME);
OM_uint32 major, init_flags;
*minor = 0;
if (local)
return GSS_S_COMPLETE;
if (sc == NULL) {
sc = calloc(1, sizeof(*sc));
if (sc == NULL) {
*minor = ENOMEM;
return GSS_S_FAILURE;
}
*context_handle = (gss_ctx_id_t)sc;
}
major = parse_flags_meta_data(minor, meta_data, &init_flags);
if (major != GSS_S_COMPLETE)
return major;
sc->flags |= rfc4757_to_sanon_flags(init_flags);
return GSS_S_COMPLETE;
}