/*
* Copyright (c) 2011, PADL Software Pty Ltd.
* 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 PADL Software 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 PADL SOFTWARE 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 PADL SOFTWARE 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 1993 by OpenVision Technologies, Inc.
*
* Permission to use, copy, modify, distribute, and sell this software
* and its documentation for any purpose is hereby granted without fee,
* provided that the above copyright notice appears in all copies and
* that both that copyright notice and this permission notice appear in
* supporting documentation, and that the name of OpenVision not be used
* in advertising or publicity pertaining to distribution of the software
* without specific, written prior permission. OpenVision makes no
* representations about the suitability of this software for any
* purpose. It is provided "as is" without express or implied warranty.
*
* OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
* EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, 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.
*/
#include <config.h>
#include <string.h>
#include <stdlib.h>
#include "gs2_token.h"
#ifndef HAVE_GSS_ENCAPSULATE_TOKEN
/* XXXX this code currently makes the assumption that a mech oid will
never be longer than 127 bytes. This assumption is not inherent in
the interfaces, so the code can be fixed if the OSI namespace
balloons unexpectedly. */
/*
* Each token looks like this:
* 0x60 tag for APPLICATION 0, SEQUENCE
* (constructed, definite-length)
* <length> possible multiple bytes, need to parse/generate
* 0x06 tag for OBJECT IDENTIFIER
* <moid_length> compile-time constant string (assume 1 byte)
* <moid_bytes> compile-time constant string
* <inner_bytes> the ANY containing the application token
* bytes 0,1 are the token type
* bytes 2,n are the token data
*
* Note that the token type field is a feature of RFC 1964 mechanisms and
* is not used by other GSSAPI mechanisms. As such, a token type of -1
* is interpreted to mean that no token type should be expected or
* generated.
*
* For the purposes of this abstraction, the token "header" consists of
* the sequence tag and length octets, the mech OID DER encoding, and the
* first two inner bytes, which indicate the token type. The token
* "body" consists of everything else.
*/
static size_t
der_length_size(size_t length)
{
if (length < (1<<7))
return 1;
else if (length < (1<<8))
return 2;
#if INT_MAX == 0x7fff
else
return 3;
#else
else if (length < (1<<16))
return 3;
else if (length < (1<<24))
return 4;
else
return 5;
#endif
}
static void
der_write_length(unsigned char **buf, size_t length)
{
if (length < (1<<7)) {
*(*buf)++ = (unsigned char)length;
} else {
*(*buf)++ = (unsigned char)(der_length_size(length)+127);
#if INT_MAX > 0x7fff
if (length >= (1<<24))
*(*buf)++ = (unsigned char)(length>>24);
if (length >= (1<<16))
*(*buf)++ = (unsigned char)((length>>16)&0xff);
#endif
if (length >= (1<<8))
*(*buf)++ = (unsigned char)((length>>8)&0xff);
*(*buf)++ = (unsigned char)(length&0xff);
}
}
/* returns the length of a token, given the mech oid and the body size */
static size_t
token_size(const gss_OID_desc *mech, size_t body_size)
{
/* set body_size to sequence contents size */
body_size += 2 + (size_t) mech->length; /* NEED overflow check */
return 1 + der_length_size(body_size) + body_size;
}
/* fills in a buffer with the token header. The buffer is assumed to
be the right size. buf is advanced past the token header */
static void
make_token_header(
const gss_OID_desc *mech,
size_t body_size,
unsigned char **buf)
{
*(*buf)++ = 0x60;
der_write_length(buf, 2 + mech->length + body_size);
*(*buf)++ = 0x06;
*(*buf)++ = (unsigned char)mech->length;
memcpy(*buf, mech->elements, mech->length);
*buf += mech->length;
}
OM_uint32
gs2_encapsulate_token(const gss_buffer_t input_token,
const gss_OID token_oid,
gss_buffer_t output_token)
{
size_t tokenSize;
unsigned char *buf;
if (input_token == GSS_C_NO_BUFFER || token_oid == GSS_C_NO_OID)
return GSS_S_CALL_INACCESSIBLE_READ;
if (output_token == GSS_C_NO_BUFFER)
return GSS_S_CALL_INACCESSIBLE_WRITE;
tokenSize = token_size(token_oid, input_token->length);
output_token->value = malloc(tokenSize);
if (output_token->value == NULL)
return GSS_S_FAILURE;
buf = output_token->value;
make_token_header(token_oid, input_token->length, &buf);
memcpy(buf, input_token->value, input_token->length);
output_token->length = tokenSize;
return GSS_S_COMPLETE;
}
#endif
#ifndef HAVE_GSS_DECAPSULATE_TOKEN
/* returns decoded length, or < 0 on failure. Advances buf and
decrements bufsize */
static int
der_read_length(unsigned char **buf, ssize_t *bufsize)
{
unsigned char sf;
int ret;
if (*bufsize < 1)
return -1;
sf = *(*buf)++;
(*bufsize)--;
if (sf & 0x80) {
if ((sf &= 0x7f) > ((*bufsize)-1))
return -1;
if (sf > sizeof(int))
return -1;
ret = 0;
for (; sf; sf--) {
ret = (ret<<8) + (*(*buf)++);
(*bufsize)--;
}
} else {
ret = sf;
}
return ret;
}
/*
* Given a buffer containing a token, reads and verifies the token,
* leaving buf advanced past the token header, and setting body_size
* to the number of remaining bytes. Returns 0 on success,
* G_BAD_TOK_HEADER for a variety of errors, and G_WRONG_MECH if the
* mechanism in the token does not match the mech argument. buf and
* *body_size are left unmodified on error.
*/
static OM_uint32
verify_token_header(OM_uint32 *minor,
const gss_OID mech,
size_t *body_size,
unsigned char **buf_in,
size_t toksize_in)
{
unsigned char *buf = *buf_in;
ssize_t seqsize;
gss_OID_desc toid;
ssize_t toksize = (ssize_t)toksize_in;
*minor = 0;
if ((toksize -= 1) < 0)
return GSS_S_DEFECTIVE_TOKEN;
if (*buf++ != 0x60)
return GSS_S_DEFECTIVE_TOKEN;
seqsize = der_read_length(&buf, &toksize);
if (seqsize < 0)
return GSS_S_DEFECTIVE_TOKEN;
if (seqsize != toksize)
return GSS_S_DEFECTIVE_TOKEN;
if ((toksize -= 1) < 0)
return GSS_S_DEFECTIVE_TOKEN;
if (*buf++ != 0x06)
return GSS_S_DEFECTIVE_TOKEN;
if ((toksize -= 1) < 0)
return GSS_S_DEFECTIVE_TOKEN;
toid.length = *buf++;
if ((toksize -= toid.length) < 0)
return GSS_S_DEFECTIVE_TOKEN;
toid.elements = buf;
buf += toid.length;
if (!gss_oid_equal(&toid, mech))
return GSS_S_DEFECTIVE_TOKEN;
*buf_in = buf;
*body_size = toksize;
return GSS_S_COMPLETE;
}
OM_uint32
gs2_decapsulate_token(const gss_buffer_t input_token,
const gss_OID token_oid,
gss_buffer_t output_token)
{
OM_uint32 major, minor;
size_t body_size = 0;
unsigned char *buf_in;
if (input_token == GSS_C_NO_BUFFER || token_oid == GSS_C_NO_OID)
return GSS_S_CALL_INACCESSIBLE_READ;
if (output_token == GSS_C_NO_BUFFER)
return GSS_S_CALL_INACCESSIBLE_WRITE;
buf_in = input_token->value;
major = verify_token_header(&minor, token_oid, &body_size, &buf_in,
input_token->length);
if (minor != 0)
return GSS_S_DEFECTIVE_TOKEN;
output_token->value = malloc(body_size);
if (output_token->value == NULL)
return GSS_S_FAILURE;
memcpy(output_token->value, buf_in, body_size);
output_token->length = body_size;
return GSS_S_COMPLETE;
}
#endif
#ifndef HAVE_GSS_OID_EQUAL
int
gs2_oid_equal(const gss_OID o1, const gss_OID o2)
{
return o1->length == o2->length &&
(memcmp(o1->elements, o2->elements, o1->length) == 0);
}
#endif