1 /*- 2 * Copyright (c) 1999-2002, 2007 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 * 40 * Prevent processes owned by a particular uid from seeing various transient 41 * kernel objects associated with other uids. 42 */ 43 44 #include <sys/param.h> 45 #include <sys/kernel.h> 46 #include <sys/module.h> 47 #include <sys/priv.h> 48 #include <sys/proc.h> 49 #include <sys/systm.h> 50 #include <sys/socketvar.h> 51 #include <sys/sysctl.h> 52 53 #include <security/mac/mac_policy.h> 54 55 SYSCTL_DECL(_security_mac); 56 57 SYSCTL_NODE(_security_mac, OID_AUTO, seeotheruids, CTLFLAG_RW, 0, 58 "TrustedBSD mac_seeotheruids policy controls"); 59 60 static int mac_seeotheruids_enabled = 1; 61 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, enabled, CTLFLAG_RW, 62 &mac_seeotheruids_enabled, 0, "Enforce seeotheruids policy"); 63 64 /* 65 * Exception: allow credentials to be aware of other credentials with the 66 * same primary gid. 67 */ 68 static int primarygroup_enabled = 0; 69 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, primarygroup_enabled, 70 CTLFLAG_RW, &primarygroup_enabled, 0, "Make an exception for credentials " 71 "with the same real primary group id"); 72 73 /* 74 * Exception: allow the root user to be aware of other credentials by virtue 75 * of privilege. 76 */ 77 static int suser_privileged = 1; 78 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, suser_privileged, 79 CTLFLAG_RW, &suser_privileged, 0, "Make an exception for superuser"); 80 81 /* 82 * Exception: allow processes with a specific gid to be exempt from the 83 * policy. One sysctl enables this functionality; the other sets the 84 * exempt gid. 85 */ 86 static int specificgid_enabled = 0; 87 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid_enabled, 88 CTLFLAG_RW, &specificgid_enabled, 0, "Make an exception for credentials " 89 "with a specific gid as their real primary group id or group set"); 90 91 static gid_t specificgid = 0; 92 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid, CTLFLAG_RW, 93 &specificgid, 0, "Specific gid to be exempt from seeotheruids policy"); 94 95 static int 96 mac_seeotheruids_check(struct ucred *cr1, struct ucred *cr2) 97 { 98 99 if (!mac_seeotheruids_enabled) 100 return (0); 101 102 if (primarygroup_enabled) { 103 if (cr1->cr_rgid == cr2->cr_rgid) 104 return (0); 105 } 106 107 if (specificgid_enabled) { 108 if (cr1->cr_rgid == specificgid || 109 groupmember(specificgid, cr1)) 110 return (0); 111 } 112 113 if (cr1->cr_ruid == cr2->cr_ruid) 114 return (0); 115 116 if (suser_privileged) { 117 if (priv_check_cred(cr1, PRIV_SEEOTHERUIDS, 0) == 0) 118 return (0); 119 } 120 121 return (ESRCH); 122 } 123 124 static int 125 mac_seeotheruids_check_cred_visible(struct ucred *cr1, struct ucred *cr2) 126 { 127 128 return (mac_seeotheruids_check(cr1, cr2)); 129 } 130 131 static int 132 mac_seeotheruids_check_proc_signal(struct ucred *cred, struct proc *p, 133 int signum) 134 { 135 136 return (mac_seeotheruids_check(cred, p->p_ucred)); 137 } 138 139 static int 140 mac_seeotheruids_check_proc_sched(struct ucred *cred, struct proc *p) 141 { 142 143 return (mac_seeotheruids_check(cred, p->p_ucred)); 144 } 145 146 static int 147 mac_seeotheruids_check_proc_debug(struct ucred *cred, struct proc *p) 148 { 149 150 return (mac_seeotheruids_check(cred, p->p_ucred)); 151 } 152 153 static int 154 mac_seeotheruids_check_socket_visible(struct ucred *cred, struct socket *so, 155 struct label *solabel) 156 { 157 158 return (mac_seeotheruids_check(cred, so->so_cred)); 159 } 160 161 static struct mac_policy_ops mac_seeotheruids_ops = 162 { 163 .mpo_check_cred_visible = mac_seeotheruids_check_cred_visible, 164 .mpo_check_proc_debug = mac_seeotheruids_check_proc_debug, 165 .mpo_check_proc_sched = mac_seeotheruids_check_proc_sched, 166 .mpo_check_proc_signal = mac_seeotheruids_check_proc_signal, 167 .mpo_check_socket_visible = mac_seeotheruids_check_socket_visible, 168 }; 169 170 MAC_POLICY_SET(&mac_seeotheruids_ops, mac_seeotheruids, 171 "TrustedBSD MAC/seeotheruids", MPC_LOADTIME_FLAG_UNLOADOK, NULL); 172