1/*
2 * Copyright (c) 2005, PADL Software Pty Ltd.
3 * All rights reserved.
4 *
5 * Portions Copyright (c) 2009 Apple Inc. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 *
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 *
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 *
18 * 3. Neither the name of PADL Software nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY PADL SOFTWARE AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL PADL SOFTWARE OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35#include "kcm_locl.h"
36
37krb5_error_code
38kcm_access(krb5_context context,
39	   kcm_client *client,
40	   kcm_operation opcode,
41	   kcm_ccache ccache)
42{
43    int read_p = 0;
44    int write_p = 0;
45    uint16_t mask;
46    krb5_error_code ret;
47
48    KCM_ASSERT_VALID(ccache);
49
50    switch (opcode) {
51    case KCM_OP_INITIALIZE:
52    case KCM_OP_DESTROY:
53    case KCM_OP_STORE:
54    case KCM_OP_REMOVE_CRED:
55    case KCM_OP_SET_FLAGS:
56    case KCM_OP_CHOWN:
57    case KCM_OP_CHMOD:
58    case KCM_OP_GET_INITIAL_TICKET:
59    case KCM_OP_GET_TICKET:
60    case KCM_OP_MOVE_CACHE:
61    case KCM_OP_SET_DEFAULT_CACHE:
62    case KCM_OP_SET_KDC_OFFSET:
63	write_p = 1;
64	read_p = 0;
65	break;
66    case KCM_OP_NOOP:
67    case KCM_OP_GET_NAME:
68    case KCM_OP_RESOLVE:
69    case KCM_OP_GEN_NEW:
70    case KCM_OP_RETRIEVE:
71    case KCM_OP_GET_PRINCIPAL:
72    case KCM_OP_GET_CRED_UUID_LIST:
73    case KCM_OP_GET_CRED_BY_UUID:
74    case KCM_OP_GET_CACHE_UUID_LIST:
75    case KCM_OP_GET_CACHE_BY_UUID:
76    case KCM_OP_GET_DEFAULT_CACHE:
77    case KCM_OP_GET_KDC_OFFSET:
78	write_p = 0;
79	read_p = 1;
80	break;
81    default:
82	ret = KRB5_FCC_PERM;
83	goto out;
84    }
85
86    if (ccache->flags & KCM_FLAGS_OWNER_IS_SYSTEM) {
87	/* System caches cannot be reinitialized or destroyed by users */
88	if (opcode == KCM_OP_INITIALIZE ||
89	    opcode == KCM_OP_DESTROY ||
90	    opcode == KCM_OP_REMOVE_CRED ||
91	    opcode == KCM_OP_MOVE_CACHE) {
92	    ret = KRB5_FCC_PERM;
93	    goto out;
94	}
95
96	/* Let root always read system caches */
97	if (CLIENT_IS_ROOT(client)) {
98	    ret = 0;
99	    goto out;
100	}
101    }
102
103    /* start out with "other" mask */
104    mask = S_IROTH|S_IWOTH;
105
106    /* root can do anything */
107    if (CLIENT_IS_ROOT(client)) {
108	if (read_p)
109	    mask |= S_IRUSR|S_IRGRP|S_IROTH;
110	if (write_p)
111	    mask |= S_IWUSR|S_IWGRP|S_IWOTH;
112    }
113    /* same session same as owner */
114    if (kcm_is_same_session(client, ccache->uid, ccache->session)) {
115	if (read_p)
116	    mask |= S_IROTH;
117	if (write_p)
118	    mask |= S_IWOTH;
119    }
120    /* owner */
121    if (client->uid == ccache->uid) {
122	if (read_p)
123	    mask |= S_IRUSR;
124	if (write_p)
125	    mask |= S_IWUSR;
126    }
127    /* group */
128    if (client->gid == ccache->gid) {
129	if (read_p)
130	    mask |= S_IRGRP;
131	if (write_p)
132	    mask |= S_IWGRP;
133    }
134
135    ret = (ccache->mode & mask) ? 0 : KRB5_FCC_PERM;
136
137out:
138    if (ret) {
139	kcm_log(2, "Process %d is not permitted to call %s on cache %s",
140		client->pid, kcm_op2string(opcode), ccache->name);
141    }
142
143    return ret;
144}
145
146krb5_error_code
147kcm_chmod(krb5_context context,
148	  kcm_client *client,
149	  kcm_ccache ccache,
150	  uint16_t mode)
151{
152    KCM_ASSERT_VALID(ccache);
153
154    /* System cache mode can only be set at startup */
155    if (ccache->flags & KCM_FLAGS_OWNER_IS_SYSTEM)
156	return KRB5_FCC_PERM;
157
158    if (ccache->uid != client->uid)
159	return KRB5_FCC_PERM;
160
161    if (ccache->gid != client->gid)
162	return KRB5_FCC_PERM;
163
164    HEIMDAL_MUTEX_lock(&ccache->mutex);
165
166    ccache->mode = mode;
167
168    HEIMDAL_MUTEX_unlock(&ccache->mutex);
169
170    return 0;
171}
172
173krb5_error_code
174kcm_chown(krb5_context context,
175	  kcm_client *client,
176	  kcm_ccache ccache,
177	  uid_t uid,
178	  gid_t gid)
179{
180    KCM_ASSERT_VALID(ccache);
181
182    /* System cache owner can only be set at startup */
183    if (ccache->flags & KCM_FLAGS_OWNER_IS_SYSTEM)
184	return KRB5_FCC_PERM;
185
186    if (ccache->uid != client->uid)
187	return KRB5_FCC_PERM;
188
189    if (ccache->gid != client->gid)
190	return KRB5_FCC_PERM;
191
192    HEIMDAL_MUTEX_lock(&ccache->mutex);
193
194    ccache->uid = uid;
195    ccache->gid = gid;
196
197    HEIMDAL_MUTEX_unlock(&ccache->mutex);
198
199    return 0;
200}
201
202