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 * Prevent processes owned by a particular uid from seeing various transient 40 * kernel objects associated with other uids. 41 */ 42 43 #include <sys/param.h> 44 #include <sys/kernel.h> 45 #include <sys/module.h> 46 #include <sys/priv.h> 47 #include <sys/proc.h> 48 #include <sys/systm.h> 49 #include <sys/socketvar.h> 50 #include <sys/sysctl.h> 51 52 #include <security/mac/mac_policy.h> 53 54 SYSCTL_DECL(_security_mac); 55 56 SYSCTL_NODE(_security_mac, OID_AUTO, seeotheruids, CTLFLAG_RW, 0, 57 "TrustedBSD mac_seeotheruids policy controls"); 58 59 static int mac_seeotheruids_enabled = 1; 60 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, enabled, CTLFLAG_RW, 61 &mac_seeotheruids_enabled, 0, "Enforce seeotheruids policy"); 62 63 /* 64 * Exception: allow credentials to be aware of other credentials with the 65 * same primary gid. 66 */ 67 static int primarygroup_enabled = 0; 68 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, primarygroup_enabled, 69 CTLFLAG_RW, &primarygroup_enabled, 0, "Make an exception for credentials " 70 "with the same real primary group id"); 71 72 /* 73 * Exception: allow the root user to be aware of other credentials by virtue 74 * of privilege. 75 */ 76 static int suser_privileged = 1; 77 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, suser_privileged, 78 CTLFLAG_RW, &suser_privileged, 0, "Make an exception for superuser"); 79 80 /* 81 * Exception: allow processes with a specific gid to be exempt from the 82 * policy. One sysctl enables this functionality; the other sets the 83 * exempt gid. 84 */ 85 static int specificgid_enabled = 0; 86 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid_enabled, 87 CTLFLAG_RW, &specificgid_enabled, 0, "Make an exception for credentials " 88 "with a specific gid as their real primary group id or group set"); 89 90 static gid_t specificgid = 0; 91 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid, CTLFLAG_RW, 92 &specificgid, 0, "Specific gid to be exempt from seeotheruids policy"); 93 94 static int 95 mac_seeotheruids_check(struct ucred *u1, struct ucred *u2) 96 { 97 98 if (!mac_seeotheruids_enabled) 99 return (0); 100 101 if (primarygroup_enabled) { 102 if (u1->cr_rgid == u2->cr_rgid) 103 return (0); 104 } 105 106 if (specificgid_enabled) { 107 if (u1->cr_rgid == specificgid || groupmember(specificgid, u1)) 108 return (0); 109 } 110 111 if (u1->cr_ruid == u2->cr_ruid) 112 return (0); 113 114 if (suser_privileged) { 115 if (priv_check_cred(u1, PRIV_SEEOTHERUIDS, SUSER_ALLOWJAIL) 116 == 0) 117 return (0); 118 } 119 120 return (ESRCH); 121 } 122 123 static int 124 mac_seeotheruids_check_cred_visible(struct ucred *u1, struct ucred *u2) 125 { 126 127 return (mac_seeotheruids_check(u1, u2)); 128 } 129 130 static int 131 mac_seeotheruids_check_proc_signal(struct ucred *cred, struct proc *proc, 132 int signum) 133 { 134 135 return (mac_seeotheruids_check(cred, proc->p_ucred)); 136 } 137 138 static int 139 mac_seeotheruids_check_proc_sched(struct ucred *cred, struct proc *proc) 140 { 141 142 return (mac_seeotheruids_check(cred, proc->p_ucred)); 143 } 144 145 static int 146 mac_seeotheruids_check_proc_debug(struct ucred *cred, struct proc *proc) 147 { 148 149 return (mac_seeotheruids_check(cred, proc->p_ucred)); 150 } 151 152 static int 153 mac_seeotheruids_check_socket_visible(struct ucred *cred, struct socket *socket, 154 struct label *socketlabel) 155 { 156 157 return (mac_seeotheruids_check(cred, socket->so_cred)); 158 } 159 160 static struct mac_policy_ops mac_seeotheruids_ops = 161 { 162 .mpo_check_cred_visible = mac_seeotheruids_check_cred_visible, 163 .mpo_check_proc_debug = mac_seeotheruids_check_proc_debug, 164 .mpo_check_proc_sched = mac_seeotheruids_check_proc_sched, 165 .mpo_check_proc_signal = mac_seeotheruids_check_proc_signal, 166 .mpo_check_socket_visible = mac_seeotheruids_check_socket_visible, 167 }; 168 169 MAC_POLICY_SET(&mac_seeotheruids_ops, mac_seeotheruids, 170 "TrustedBSD MAC/seeotheruids", MPC_LOADTIME_FLAG_UNLOADOK, NULL); 171