1/*-
2 * Copyright (c) 2008 Doug Rabson
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28
29#include <gssapi/gssapi.h>
30#include <stdlib.h>
31#include <string.h>
32
33#include "utils.h"
34
35OM_uint32
36gss_encapsulate_token(const gss_buffer_t input_token, gss_OID oid,
37    gss_buffer_t output_token)
38{
39	unsigned char *p;
40	size_t len, inside_len;
41	size_t a, b;
42	int i;
43
44	_gss_buffer_zero(output_token);
45
46	/*
47	 * First time around, we calculate the size, second time, we
48	 * encode the token.
49	 */
50	p = NULL;
51	for (i = 0; i < 2; i++) {
52		len = 0;
53
54		/*
55		 * Token starts with [APPLICATION 0] SEQUENCE.
56		 */
57		if (p)
58			*p++ = 0x60;
59		len++;
60
61		/*
62		 * The length embedded in the token is the space
63		 * needed for the encapsulated oid plus the length of
64		 * the inner token.
65		 */
66		if (oid->length > 127)
67			return (GSS_S_DEFECTIVE_TOKEN);
68
69		inside_len = 2 + oid->length + input_token->length;
70
71		/*
72		 * Figure out how to encode the length
73		 */
74		if (inside_len < 128) {
75			if (p)
76				*p++ = inside_len;
77			len++;
78		} else {
79			b = 1;
80			if (inside_len >= 0x100)
81				b++;
82			if (inside_len >= 0x10000)
83				b++;
84			if (inside_len >= 0x1000000)
85				b++;
86			if (p)
87				*p++ = b | 0x80;
88			len++;
89			a = inside_len << 8*(4 - b);
90			while (b) {
91				if (p)
92					*p++ = (a >> 24);
93				a <<= 8;
94				len++;
95				b--;
96			}
97		}
98
99		/*
100		 * Encode the OID for the mechanism. Simplify life by
101		 * assuming that the OID length is less than 128 bytes.
102		 */
103		if (p)
104			*p++ = 0x06;
105		len++;
106		if (p)
107			*p++ = oid->length;
108		len++;
109		if (p) {
110			memcpy(p, oid->elements, oid->length);
111			p += oid->length;
112		}
113		len += oid->length;
114
115		if (p) {
116			memcpy(p, input_token->value, input_token->length);
117			p += input_token->length;
118		}
119		len += input_token->length;
120
121		if (i == 0) {
122			output_token->length = len;
123			output_token->value = malloc(len);
124			if (!output_token->value)
125				return (GSS_S_DEFECTIVE_TOKEN);
126			p = output_token->value;
127		}
128	}
129
130	return (GSS_S_COMPLETE);
131}
132