1/*	$NetBSD: sequence.c,v 1.1.1.1 2011/04/13 18:14:45 elric Exp $	*/
2
3/*
4 * Copyright (c) 2003 - 2006 Kungliga Tekniska Högskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include "gsskrb5_locl.h"
37
38#define DEFAULT_JITTER_WINDOW 20
39
40struct gss_msg_order {
41    OM_uint32 flags;
42    OM_uint32 start;
43    OM_uint32 length;
44    OM_uint32 jitter_window;
45    OM_uint32 first_seq;
46    OM_uint32 elem[1];
47};
48
49
50/*
51 *
52 */
53
54static OM_uint32
55msg_order_alloc(OM_uint32 *minor_status,
56		struct gss_msg_order **o,
57		OM_uint32 jitter_window)
58{
59    size_t len;
60
61    len = jitter_window * sizeof((*o)->elem[0]);
62    len += sizeof(**o);
63    len -= sizeof((*o)->elem[0]);
64
65    *o = calloc(1, len);
66    if (*o == NULL) {
67	*minor_status = ENOMEM;
68	return GSS_S_FAILURE;
69    }
70
71    *minor_status = 0;
72    return GSS_S_COMPLETE;
73}
74
75/*
76 *
77 */
78
79OM_uint32
80_gssapi_msg_order_create(OM_uint32 *minor_status,
81			 struct gss_msg_order **o,
82			 OM_uint32 flags,
83			 OM_uint32 seq_num,
84			 OM_uint32 jitter_window,
85			 int use_64)
86{
87    OM_uint32 ret;
88
89    if (jitter_window == 0)
90	jitter_window = DEFAULT_JITTER_WINDOW;
91
92    ret = msg_order_alloc(minor_status, o, jitter_window);
93    if(ret != GSS_S_COMPLETE)
94        return ret;
95
96    (*o)->flags = flags;
97    (*o)->length = 0;
98    (*o)->first_seq = seq_num;
99    (*o)->jitter_window = jitter_window;
100    (*o)->elem[0] = seq_num - 1;
101
102    *minor_status = 0;
103    return GSS_S_COMPLETE;
104}
105
106OM_uint32
107_gssapi_msg_order_destroy(struct gss_msg_order **m)
108{
109    free(*m);
110    *m = NULL;
111    return GSS_S_COMPLETE;
112}
113
114static void
115elem_set(struct gss_msg_order *o, unsigned int slot, OM_uint32 val)
116{
117    o->elem[slot % o->jitter_window] = val;
118}
119
120static void
121elem_insert(struct gss_msg_order *o,
122	    unsigned int after_slot,
123	    OM_uint32 seq_num)
124{
125    assert(o->jitter_window > after_slot);
126
127    if (o->length > after_slot)
128	memmove(&o->elem[after_slot + 1], &o->elem[after_slot],
129		(o->length - after_slot - 1) * sizeof(o->elem[0]));
130
131    elem_set(o, after_slot, seq_num);
132
133    if (o->length < o->jitter_window)
134	o->length++;
135}
136
137/* rule 1: expected sequence number */
138/* rule 2: > expected sequence number */
139/* rule 3: seqnum < seqnum(first) */
140/* rule 4+5: seqnum in [seqnum(first),seqnum(last)]  */
141
142OM_uint32
143_gssapi_msg_order_check(struct gss_msg_order *o, OM_uint32 seq_num)
144{
145    OM_uint32 r;
146    int i;
147
148    if (o == NULL)
149	return GSS_S_COMPLETE;
150
151    if ((o->flags & (GSS_C_REPLAY_FLAG|GSS_C_SEQUENCE_FLAG)) == 0)
152	return GSS_S_COMPLETE;
153
154    /* check if the packet is the next in order */
155    if (o->elem[0] == seq_num - 1) {
156	elem_insert(o, 0, seq_num);
157	return GSS_S_COMPLETE;
158    }
159
160    r = (o->flags & (GSS_C_REPLAY_FLAG|GSS_C_SEQUENCE_FLAG))==GSS_C_REPLAY_FLAG;
161
162    /* sequence number larger then largest sequence number
163     * or smaller then the first sequence number */
164    if (seq_num > o->elem[0]
165	|| seq_num < o->first_seq
166	|| o->length == 0)
167    {
168	elem_insert(o, 0, seq_num);
169	if (r) {
170	    return GSS_S_COMPLETE;
171	} else {
172	    return GSS_S_GAP_TOKEN;
173	}
174    }
175
176    assert(o->length > 0);
177
178    /* sequence number smaller the first sequence number */
179    if (seq_num < o->elem[o->length - 1]) {
180	if (r)
181	    return(GSS_S_OLD_TOKEN);
182	else
183	    return(GSS_S_UNSEQ_TOKEN);
184    }
185
186    if (seq_num == o->elem[o->length - 1]) {
187	return GSS_S_DUPLICATE_TOKEN;
188    }
189
190    for (i = 0; i < o->length - 1; i++) {
191	if (o->elem[i] == seq_num)
192	    return GSS_S_DUPLICATE_TOKEN;
193	if (o->elem[i + 1] < seq_num && o->elem[i] < seq_num) {
194	    elem_insert(o, i, seq_num);
195	    if (r)
196		return GSS_S_COMPLETE;
197	    else
198		return GSS_S_UNSEQ_TOKEN;
199	}
200    }
201
202    return GSS_S_FAILURE;
203}
204
205OM_uint32
206_gssapi_msg_order_f(OM_uint32 flags)
207{
208    return flags & (GSS_C_SEQUENCE_FLAG|GSS_C_REPLAY_FLAG);
209}
210
211/*
212 * Translate `o` into inter-process format and export in to `sp'.
213 */
214
215krb5_error_code
216_gssapi_msg_order_export(krb5_storage *sp, struct gss_msg_order *o)
217{
218    krb5_error_code kret;
219    OM_uint32 i;
220
221    kret = krb5_store_int32(sp, o->flags);
222    if (kret)
223        return kret;
224    kret = krb5_store_int32(sp, o->start);
225    if (kret)
226        return kret;
227    kret = krb5_store_int32(sp, o->length);
228    if (kret)
229        return kret;
230    kret = krb5_store_int32(sp, o->jitter_window);
231    if (kret)
232        return kret;
233    kret = krb5_store_int32(sp, o->first_seq);
234    if (kret)
235        return kret;
236
237    for (i = 0; i < o->jitter_window; i++) {
238        kret = krb5_store_int32(sp, o->elem[i]);
239	if (kret)
240	    return kret;
241    }
242
243    return 0;
244}
245
246OM_uint32
247_gssapi_msg_order_import(OM_uint32 *minor_status,
248			 krb5_storage *sp,
249			 struct gss_msg_order **o)
250{
251    OM_uint32 ret;
252    krb5_error_code kret;
253    int32_t i, flags, start, length, jitter_window, first_seq;
254
255    kret = krb5_ret_int32(sp, &flags);
256    if (kret)
257	goto failed;
258    kret = krb5_ret_int32(sp, &start);
259    if (kret)
260	goto failed;
261    kret = krb5_ret_int32(sp, &length);
262    if (kret)
263	goto failed;
264    kret = krb5_ret_int32(sp, &jitter_window);
265    if (kret)
266	goto failed;
267    kret = krb5_ret_int32(sp, &first_seq);
268    if (kret)
269	goto failed;
270
271    ret = msg_order_alloc(minor_status, o, jitter_window);
272    if (ret != GSS_S_COMPLETE)
273        return ret;
274
275    (*o)->flags = flags;
276    (*o)->start = start;
277    (*o)->length = length;
278    (*o)->jitter_window = jitter_window;
279    (*o)->first_seq = first_seq;
280
281    for( i = 0; i < jitter_window; i++ ) {
282        kret = krb5_ret_int32(sp, (int32_t*)&((*o)->elem[i]));
283	if (kret)
284	    goto failed;
285    }
286
287    *minor_status = 0;
288    return GSS_S_COMPLETE;
289
290failed:
291    _gssapi_msg_order_destroy(o);
292    *minor_status = kret;
293    return GSS_S_FAILURE;
294}
295