xref: /freebsd/sys/security/mac_priority/mac_priority.c (revision f81cdf24ba5436367377f7c8e8f51f6df2a75ca7)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2021 Florian Walpen <dev@submerge.ch>
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  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25  * SUCH DAMAGE.
26  */
27 
28 #include <sys/param.h>
29 #include <sys/conf.h>
30 #include <sys/kernel.h>
31 #include <sys/module.h>
32 #include <sys/priv.h>
33 #include <sys/sysctl.h>
34 #include <sys/ucred.h>
35 
36 #include <security/mac/mac_policy.h>
37 
38 SYSCTL_DECL(_security_mac);
39 
40 static SYSCTL_NODE(_security_mac, OID_AUTO, priority,
41     CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
42     "mac_priority policy controls");
43 
44 static int realtime_enabled = 1;
45 SYSCTL_INT(_security_mac_priority, OID_AUTO, realtime, CTLFLAG_RWTUN,
46     &realtime_enabled, 0,
47     "Enable realtime priority scheduling for group realtime_gid");
48 
49 static int realtime_gid = GID_RT_PRIO;
50 SYSCTL_INT(_security_mac_priority, OID_AUTO, realtime_gid, CTLFLAG_RWTUN,
51     &realtime_gid, 0,
52     "Group id of the realtime privilege group");
53 
54 static int idletime_enabled = 1;
55 SYSCTL_INT(_security_mac_priority, OID_AUTO, idletime, CTLFLAG_RWTUN,
56     &idletime_enabled, 0,
57     "Enable idle priority scheduling for group idletime_gid");
58 
59 static int idletime_gid = GID_ID_PRIO;
60 SYSCTL_INT(_security_mac_priority, OID_AUTO, idletime_gid, CTLFLAG_RWTUN,
61     &idletime_gid, 0,
62     "Group id of the idletime privilege group");
63 
64 static int
65 priority_priv_grant(struct ucred *cred, int priv)
66 {
67 	if ((priv == PRIV_SCHED_RTPRIO || priv == PRIV_SCHED_SETPOLICY) &&
68 	    realtime_enabled && groupmember(realtime_gid, cred))
69 		return (0);
70 
71 	if (priv == PRIV_SCHED_IDPRIO && idletime_enabled &&
72 	    groupmember(idletime_gid, cred))
73 		return (0);
74 
75 	return (EPERM);
76 }
77 
78 static struct mac_policy_ops priority_ops = {
79 	.mpo_priv_grant = priority_priv_grant,
80 };
81 
82 MAC_POLICY_SET(&priority_ops, mac_priority, "MAC/priority",
83     MPC_LOADTIME_FLAG_UNLOADOK, NULL);
84