/*-
* Copyright (c) 2005 Doug Rabson
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*
* $FreeBSD: src/lib/libgssapi/gss_accept_sec_context.c,v 1.1 2005/12/29 14:40:20 dfr Exp $
*/
#include "mech_locl.h"
static OM_uint32
parse_header(const gss_buffer_t input_token, gss_OID mech_oid)
{
unsigned char *p = input_token->value;
size_t len = input_token->length;
size_t a, b;
/*
* Token must start with [APPLICATION 0] SEQUENCE.
* But if it doesn't assume it is DCE-STYLE Kerberos!
*/
if (len == 0)
return (GSS_S_DEFECTIVE_TOKEN);
p++;
len--;
/*
* Decode the length and make sure it agrees with the
* token length.
*/
if (len == 0)
return (GSS_S_DEFECTIVE_TOKEN);
if ((*p & 0x80) == 0) {
a = *p;
p++;
len--;
} else {
b = *p & 0x7f;
p++;
len--;
if (len < b)
return (GSS_S_DEFECTIVE_TOKEN);
a = 0;
while (b) {
a = (a << 8) | *p;
p++;
len--;
b--;
}
}
if (a != len)
return (GSS_S_DEFECTIVE_TOKEN);
/*
* Decode the OID for the mechanism. Simplify life by
* assuming that the OID length is less than 128 bytes.
*/
if (len < 2 || *p != 0x06)
return (GSS_S_DEFECTIVE_TOKEN);
if ((p[1] & 0x80) || p[1] > (len - 2))
return (GSS_S_DEFECTIVE_TOKEN);
mech_oid->length = p[1];
p += 2;
len -= 2;
mech_oid->elements = p;
return GSS_S_COMPLETE;
}
static gss_OID_desc krb5_mechanism =
{9, rk_UNCONST("\x2a\x86\x48\x86\xf7\x12\x01\x02\x02")};
static gss_OID_desc ntlm_mechanism =
{10, rk_UNCONST("\x2b\x06\x01\x04\x01\x82\x37\x02\x02\x0a")};
static gss_OID_desc spnego_mechanism =
{6, rk_UNCONST("\x2b\x06\x01\x05\x05\x02")};
static OM_uint32
choose_mech(const gss_buffer_t input, gss_OID mech_oid)
{
OM_uint32 status;
/*
* First try to parse the gssapi token header and see if it's a
* correct header, use that in the first hand.
*/
status = parse_header(input, mech_oid);
if (status == GSS_S_COMPLETE)
return GSS_S_COMPLETE;
/*
* Lets guess what mech is really is, callback function to mech ??
*/
if (input->length > 8 &&
memcmp((const char *)input->value, "NTLMSSP\x00", 8) == 0)
{
*mech_oid = ntlm_mechanism;
return GSS_S_COMPLETE;
} else if (input->length != 0 &&
((const char *)input->value)[0] == 0x6E)
{
/* Could be a raw AP-REQ (check for APPLICATION tag) */
*mech_oid = krb5_mechanism;
return GSS_S_COMPLETE;
} else if (input->length == 0) {
/*
* There is the a wierd mode of SPNEGO (in CIFS and
* SASL GSS-SPENGO where the first token is zero
* length and the acceptor returns a mech_list, lets
* hope that is what is happening now.
*
* http://msdn.microsoft.com/en-us/library/cc213114.aspx
* "NegTokenInit2 Variation for Server-Initiation"
*/
*mech_oid = spnego_mechanism;
return GSS_S_COMPLETE;
}
return status;
}
GSSAPI_LIB_FUNCTION OM_uint32 GSSAPI_LIB_CALL
gss_accept_sec_context(OM_uint32 *minor_status,
gss_ctx_id_t *context_handle,
const gss_cred_id_t acceptor_cred_handle,
const gss_buffer_t input_token,
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)
{
OM_uint32 major_status, mech_ret_flags, junk;
gssapi_mech_interface m;
struct _gss_context *ctx = (struct _gss_context *) *context_handle;
struct _gss_cred *cred = (struct _gss_cred *) acceptor_cred_handle;
struct _gss_mechanism_cred *mc;
gss_cred_id_t acceptor_mc, delegated_mc;
gss_name_t src_mn;
gss_OID mech_ret_type = NULL;
*minor_status = 0;
if (src_name)
*src_name = GSS_C_NO_NAME;
if (mech_type)
*mech_type = GSS_C_NO_OID;
if (ret_flags)
*ret_flags = 0;
if (time_rec)
*time_rec = 0;
if (delegated_cred_handle)
*delegated_cred_handle = GSS_C_NO_CREDENTIAL;
_mg_buffer_zero(output_token);
/*
* If this is the first call (*context_handle is NULL), we must
* parse the input token to figure out the mechanism to use.
*/
if (*context_handle == GSS_C_NO_CONTEXT) {
gss_OID_desc mech_oid;
major_status = choose_mech(input_token, &mech_oid);
if (major_status != GSS_S_COMPLETE)
return major_status;
/*
* Now that we have a mechanism, we can find the
* implementation.
*/
ctx = malloc(sizeof(struct _gss_context));
if (!ctx) {
*minor_status = ENOMEM;
return (GSS_S_DEFECTIVE_TOKEN);
}
memset(ctx, 0, sizeof(struct _gss_context));
m = ctx->gc_mech = __gss_get_mechanism(&mech_oid);
if (!m) {
free(ctx);
return (GSS_S_BAD_MECH);
}
*context_handle = (gss_ctx_id_t) ctx;
} else {
m = ctx->gc_mech;
}
if (cred) {
HEIM_SLIST_FOREACH(mc, &cred->gc_mc, gmc_link)
if (mc->gmc_mech == m)
break;
if (!mc) {
gss_delete_sec_context(&junk, context_handle, NULL);
return (GSS_S_BAD_MECH);
}
acceptor_mc = mc->gmc_cred;
} else {
acceptor_mc = GSS_C_NO_CREDENTIAL;
}
delegated_mc = GSS_C_NO_CREDENTIAL;
mech_ret_flags = 0;
major_status = m->gm_accept_sec_context(minor_status,
&ctx->gc_ctx,
acceptor_mc,
input_token,
input_chan_bindings,
&src_mn,
&mech_ret_type,
output_token,
&mech_ret_flags,
time_rec,
&delegated_mc);
if (major_status != GSS_S_COMPLETE &&
major_status != GSS_S_CONTINUE_NEEDED)
{
_gss_mg_error(m, major_status, *minor_status);
gss_delete_sec_context(&junk, context_handle, NULL);
return (major_status);
}
if (mech_type)
*mech_type = mech_ret_type;
if (src_name && src_mn) {
/*
* Make a new name and mark it as an MN.
*/
struct _gss_name *name = _gss_make_name(m, src_mn);
if (!name) {
m->gm_release_name(minor_status, &src_mn);
gss_delete_sec_context(&junk, context_handle, NULL);
return (GSS_S_FAILURE);
}
*src_name = (gss_name_t) name;
} else if (src_mn) {
m->gm_release_name(minor_status, &src_mn);
}
if (mech_ret_flags & GSS_C_DELEG_FLAG) {
if (!delegated_cred_handle) {
m->gm_release_cred(minor_status, &delegated_mc);
mech_ret_flags &=
~(GSS_C_DELEG_FLAG|GSS_C_DELEG_POLICY_FLAG);
} else if (gss_oid_equal(mech_ret_type, &m->gm_mech_oid) == 0) {
/*
* If the returned mech_type is not the same
* as the mech, assume its pseudo mech type
* and the returned type is already a
* mech-glue object
*/
*delegated_cred_handle = delegated_mc;
} else if (delegated_mc) {
struct _gss_cred *dcred;
struct _gss_mechanism_cred *dmc;
dcred = malloc(sizeof(struct _gss_cred));
if (!dcred) {
*minor_status = ENOMEM;
gss_delete_sec_context(&junk, context_handle, NULL);
return (GSS_S_FAILURE);
}
HEIM_SLIST_INIT(&dcred->gc_mc);
dmc = malloc(sizeof(struct _gss_mechanism_cred));
if (!dmc) {
free(dcred);
*minor_status = ENOMEM;
gss_delete_sec_context(&junk, context_handle, NULL);
return (GSS_S_FAILURE);
}
dmc->gmc_mech = m;
dmc->gmc_mech_oid = &m->gm_mech_oid;
dmc->gmc_cred = delegated_mc;
HEIM_SLIST_INSERT_HEAD(&dcred->gc_mc, dmc, gmc_link);
*delegated_cred_handle = (gss_cred_id_t) dcred;
}
}
if (ret_flags)
*ret_flags = mech_ret_flags;
return (major_status);
}