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