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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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331
lib/gssapi/sanon/crypto.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
_gss_sanon_wrap(OM_uint32 *minor,
gss_const_ctx_id_t context_handle,
int conf_req_flag,
gss_qop_t qop_req,
const gss_buffer_t input_message_buffer,
int *conf_state,
gss_buffer_t output_message_buffer)
{
const sanon_ctx sc = (const sanon_ctx)context_handle;
if (sc->rfc4121 == GSS_C_NO_CONTEXT) {
*minor = GSS_KRB5_S_KG_CTX_INCOMPLETE;
return GSS_S_NO_CONTEXT;
}
return gss_wrap(minor, sc->rfc4121,
conf_req_flag, qop_req,
input_message_buffer, conf_state,
output_message_buffer);
}
OM_uint32 GSSAPI_CALLCONV
_gss_sanon_wrap_size_limit(OM_uint32 *minor,
gss_const_ctx_id_t context_handle,
int conf_req_flag,
gss_qop_t qop_req,
OM_uint32 req_output_size,
OM_uint32 *max_input_size)
{
const sanon_ctx sc = (const sanon_ctx)context_handle;
if (sc->rfc4121 == GSS_C_NO_CONTEXT) {
*minor = GSS_KRB5_S_KG_CTX_INCOMPLETE;
return GSS_S_NO_CONTEXT;
}
return gss_wrap_size_limit(minor, sc->rfc4121,
conf_req_flag, qop_req,
req_output_size, max_input_size);
}
OM_uint32 GSSAPI_CALLCONV
_gss_sanon_wrap_iov(OM_uint32 *minor,
gss_ctx_id_t context_handle,
int conf_req_flag,
gss_qop_t qop_req,
int *conf_state,
gss_iov_buffer_desc *iov,
int iov_count)
{
const sanon_ctx sc = (const sanon_ctx)context_handle;
if (sc->rfc4121 == GSS_C_NO_CONTEXT) {
*minor = GSS_KRB5_S_KG_CTX_INCOMPLETE;
return GSS_S_NO_CONTEXT;
}
return gss_wrap_iov(minor, sc->rfc4121,
conf_req_flag, qop_req,
conf_state, iov, iov_count);
}
OM_uint32 GSSAPI_CALLCONV
_gss_sanon_wrap_iov_length(OM_uint32 *minor,
gss_ctx_id_t context_handle,
int conf_req_flag,
gss_qop_t qop_req,
int *conf_state,
gss_iov_buffer_desc *iov,
int iov_count)
{
const sanon_ctx sc = (const sanon_ctx)context_handle;
if (sc->rfc4121 == GSS_C_NO_CONTEXT) {
*minor = GSS_KRB5_S_KG_CTX_INCOMPLETE;
return GSS_S_NO_CONTEXT;
}
return gss_wrap_iov_length(minor, sc->rfc4121,
conf_req_flag, qop_req,
conf_state, iov, iov_count);
}
OM_uint32 GSSAPI_CALLCONV
_gss_sanon_unwrap(OM_uint32 *minor,
gss_const_ctx_id_t context_handle,
const gss_buffer_t input_message_buffer,
gss_buffer_t output_message_buffer,
int *conf_state,
gss_qop_t * qop_state)
{
const sanon_ctx sc = (const sanon_ctx)context_handle;
if (sc->rfc4121 == GSS_C_NO_CONTEXT) {
*minor = GSS_KRB5_S_KG_CTX_INCOMPLETE;
return GSS_S_NO_CONTEXT;
}
return gss_unwrap(minor, sc->rfc4121,
input_message_buffer, output_message_buffer,
conf_state, qop_state);
}
OM_uint32 GSSAPI_CALLCONV
_gss_sanon_unwrap_iov(OM_uint32 *minor,
gss_ctx_id_t context_handle,
int *conf_state,
gss_qop_t *qop_state,
gss_iov_buffer_desc *iov,
int iov_count)
{
const sanon_ctx sc = (const sanon_ctx)context_handle;
if (sc->rfc4121 == GSS_C_NO_CONTEXT) {
*minor = GSS_KRB5_S_KG_CTX_INCOMPLETE;
return GSS_S_NO_CONTEXT;
}
return gss_unwrap_iov(minor, sc->rfc4121,
conf_state, qop_state,
iov, iov_count);
}
OM_uint32 GSSAPI_CALLCONV
_gss_sanon_get_mic(OM_uint32 *minor,
gss_const_ctx_id_t context_handle,
gss_qop_t qop_req,
const gss_buffer_t message_buffer,
gss_buffer_t message_token)
{
const sanon_ctx sc = (const sanon_ctx)context_handle;
if (sc->rfc4121 == GSS_C_NO_CONTEXT) {
*minor = GSS_KRB5_S_KG_CTX_INCOMPLETE;
return GSS_S_NO_CONTEXT;
}
return gss_get_mic(minor, sc->rfc4121,
qop_req, message_buffer,
message_token);
}
OM_uint32 GSSAPI_CALLCONV
_gss_sanon_verify_mic(OM_uint32 *minor,
gss_const_ctx_id_t context_handle,
const gss_buffer_t message_buffer,
const gss_buffer_t token_buffer,
gss_qop_t *qop_state)
{
const sanon_ctx sc = (const sanon_ctx)context_handle;
if (sc->rfc4121 == GSS_C_NO_CONTEXT) {
*minor = GSS_KRB5_S_KG_CTX_INCOMPLETE;
return GSS_S_NO_CONTEXT;
}
return gss_verify_mic(minor, sc->rfc4121,
message_buffer, token_buffer,
qop_state);
}
OM_uint32 GSSAPI_CALLCONV
_gss_sanon_pseudo_random(OM_uint32 *minor,
gss_ctx_id_t context_handle,
int prf_key,
const gss_buffer_t prf_in,
ssize_t desired_output_len,
gss_buffer_t prf_out)
{
const sanon_ctx sc = (const sanon_ctx)context_handle;
if (sc->rfc4121 == GSS_C_NO_CONTEXT) {
*minor = GSS_KRB5_S_KG_CTX_INCOMPLETE;
return GSS_S_NO_CONTEXT;
}
return gss_pseudo_random(minor, sc->rfc4121,
prf_key, prf_in, desired_output_len,
prf_out);
}
/*
* Generate a curve25519 secret and public key
*/
OM_uint32
_gss_sanon_curve25519_base(OM_uint32 *minor, sanon_ctx sc)
{
krb5_generate_random_block(sc->sk, crypto_scalarmult_curve25519_BYTES);
if (crypto_scalarmult_curve25519_base(sc->pk, sc->sk) != 0) {
*minor = EINVAL;
return GSS_S_FAILURE;
}
return GSS_S_COMPLETE;
}
/*
* Derive the context session key using SP800-108 KDF in HMAC mode
* and the public keys and channel binding data.
*/
OM_uint32
_gss_sanon_curve25519(OM_uint32 *minor,
sanon_ctx sc,
gss_buffer_t pk,
const gss_channel_bindings_t input_chan_bindings,
gss_buffer_t session_key)
{
uint8_t shared[crypto_scalarmult_curve25519_BYTES], *p;
krb5_error_code ret;
krb5_context context;
krb5_data kdf_K1, kdf_label, kdf_context, keydata;
_mg_buffer_zero(session_key);
if (pk == GSS_C_NO_BUFFER || pk->length != crypto_scalarmult_curve25519_BYTES)
return GSS_S_DEFECTIVE_TOKEN;
if (crypto_scalarmult_curve25519(shared, sc->sk, pk->value) != 0)
return GSS_S_FAILURE;
ret = krb5_init_context(&context);
if (ret != 0) {
*minor = ret;
return GSS_S_FAILURE;
}
kdf_K1.data = shared;
kdf_K1.length = sizeof(shared);
kdf_label.data = "sanon-x25519";
kdf_label.length = sizeof("sanon-x25519") - 1;
ret = krb5_data_alloc(&kdf_context,
2 * crypto_scalarmult_curve25519_BYTES +
(input_chan_bindings ? input_chan_bindings->application_data.length : 0));
if (ret != 0) {
krb5_free_context(context);
*minor = ret;
return GSS_S_FAILURE;
}
p = kdf_context.data;
if (sc->flags & SANON_FLAG_INITIATOR) {
memcpy(p, sc->pk, sizeof(sc->pk));
memcpy(&p[pk->length], pk->value, pk->length);
} else {
memcpy(p, pk->value, pk->length);
memcpy(&p[sizeof(sc->pk)], sc->pk, sizeof(sc->pk));
}
if (input_chan_bindings != GSS_C_NO_CHANNEL_BINDINGS &&
input_chan_bindings->application_data.value != NULL) {
memcpy(&p[2 * crypto_scalarmult_curve25519_BYTES],
input_chan_bindings->application_data.value,
input_chan_bindings->application_data.length);
}
ret = krb5_data_alloc(&keydata, 16);
if (ret == 0) {
ret = _krb5_SP800_108_HMAC_KDF(context, &kdf_K1, &kdf_label,
&kdf_context, EVP_sha256(), &keydata);
session_key->length = keydata.length;
session_key->value = keydata.data;
} else {
krb5_data_free(&keydata);
}
memset_s(kdf_context.data, kdf_context.length, 0, kdf_context.length);
krb5_data_free(&kdf_context);
memset_s(shared, sizeof(shared), 0, sizeof(shared));
krb5_free_context(context);
*minor = ret;
return ret != 0 ? GSS_S_FAILURE : GSS_S_COMPLETE;
}
OM_uint32
_gss_sanon_import_rfc4121_context(OM_uint32 *minor,
sanon_ctx sc,
OM_uint32 flags,
gss_const_buffer_t session_key)
{
return _gss_mg_import_rfc4121_context(minor,
!!(sc->flags & SANON_FLAG_INITIATOR),
flags,
KRB5_ENCTYPE_AES128_CTS_HMAC_SHA256_128,
session_key,
&sc->rfc4121);
}