1 /*-
2 * Copyright (c) 1999-2002 Robert N. M. Watson
3 * Copyright (c) 2001-2002 Networks Associates Technology, Inc.
4 * All rights reserved.
5 *
6 * This software was developed by Robert Watson for the TrustedBSD Project.
7 *
8 * This software was developed for the FreeBSD Project in part by Network
9 * Associates Laboratories, the Security Research Division of Network
10 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"),
11 * as part of the DARPA CHATS research program.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 THE AUTHOR 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 * $FreeBSD$
35 */
36
37 /*
38 * Developed by the TrustedBSD Project.
39 * Prevent processes owned by a particular uid from seeing various transient
40 * kernel objects associated with other uids.
41 */
42
43 #include <sys/types.h>
44 #include <sys/param.h>
45 #include <sys/conf.h>
46 #include <sys/kernel.h>
47 #include <sys/mac.h>
48 #include <sys/mount.h>
49 #include <sys/proc.h>
50 #include <sys/systm.h>
51 #include <sys/sysproto.h>
52 #include <sys/sysent.h>
53 #include <sys/vnode.h>
54 #include <sys/file.h>
55 #include <sys/socket.h>
56 #include <sys/socketvar.h>
57 #include <sys/sysctl.h>
58
59 #include <net/bpfdesc.h>
60 #include <net/if.h>
61 #include <net/if_types.h>
62 #include <net/if_var.h>
63
64 #include <vm/vm.h>
65
66 #include <sys/mac_policy.h>
67
68 SYSCTL_DECL(_security_mac);
69
70 SYSCTL_NODE(_security_mac, OID_AUTO, seeotheruids, CTLFLAG_RW, 0,
71 "TrustedBSD mac_seeotheruids policy controls");
72
73 static int mac_seeotheruids_enabled = 1;
74 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, enabled, CTLFLAG_RW,
75 &mac_seeotheruids_enabled, 0, "Enforce seeotheruids policy");
76
77 /*
78 * Exception: allow credentials to be aware of other credentials with the
79 * same primary gid.
80 */
81 static int primarygroup_enabled = 0;
82 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, primarygroup_enabled,
83 CTLFLAG_RW, &primarygroup_enabled, 0, "Make an exception for credentials "
84 "with the same real primary group id");
85
86 /*
87 * Exception: allow processes with a specific gid to be exempt from the
88 * policy. One sysctl enables this functionality; the other sets the
89 * exempt gid.
90 */
91 static int specificgid_enabled = 0;
92 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid_enabled,
93 CTLFLAG_RW, &specificgid_enabled, 0, "Make an exception for credentials "
94 "with a specific gid as their real primary group id or group set");
95
96 static gid_t specificgid = 0;
97 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid, CTLFLAG_RW,
98 &specificgid, 0, "Specific gid to be exempt from seeotheruids policy");
99
100 static int
101 mac_seeotheruids_check(struct ucred *u1, struct ucred *u2)
102 {
103
104 if (!mac_seeotheruids_enabled)
105 return (0);
106
107 if (primarygroup_enabled) {
108 if (u1->cr_rgid == u2->cr_rgid)
109 return (0);
110 }
111
112 if (specificgid_enabled) {
113 if (u1->cr_rgid == specificgid || groupmember(specificgid, u1))
114 return (0);
115 }
116
117 if (u1->cr_ruid == u2->cr_ruid)
118 return (0);
119
120 if (suser_cred(u1, SUSER_ALLOWJAIL) == 0)
121 return (0);
122
123 return (ESRCH);
124 }
125
126 static int
127 mac_seeotheruids_check_cred_visible(struct ucred *u1, struct ucred *u2)
128 {
129
130 return (mac_seeotheruids_check(u1, u2));
131 }
132
133 static int
134 mac_seeotheruids_check_proc_signal(struct ucred *cred, struct proc *proc,
135 int signum)
136 {
137
138 return (mac_seeotheruids_check(cred, proc->p_ucred));
139 }
140
141 static int
142 mac_seeotheruids_check_proc_sched(struct ucred *cred, struct proc *proc)
143 {
144
145 return (mac_seeotheruids_check(cred, proc->p_ucred));
146 }
147
148 static int
149 mac_seeotheruids_check_proc_debug(struct ucred *cred, struct proc *proc)
150 {
151
152 return (mac_seeotheruids_check(cred, proc->p_ucred));
153 }
154
155 static int
156 mac_seeotheruids_check_socket_visible(struct ucred *cred, struct socket *socket,
157 struct label *socketlabel)
158 {
159
160 return (mac_seeotheruids_check(cred, socket->so_cred));
161 }
162
163 static struct mac_policy_ops mac_seeotheruids_ops =
164 {
165 .mpo_check_cred_visible = mac_seeotheruids_check_cred_visible,
166 .mpo_check_proc_debug = mac_seeotheruids_check_proc_debug,
167 .mpo_check_proc_sched = mac_seeotheruids_check_proc_sched,
168 .mpo_check_proc_signal = mac_seeotheruids_check_proc_signal,
169 .mpo_check_socket_visible = mac_seeotheruids_check_socket_visible,
170 };
171
172 MAC_POLICY_SET(&mac_seeotheruids_ops, mac_seeotheruids,
173 "TrustedBSD MAC/seeotheruids", MPC_LOADTIME_FLAG_UNLOADOK, NULL);
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