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 the root user to be aware of other credentials by virtue 88 * of privilege. 89 */ 90 static int suser_privileged = 1; 91 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, suser_privileged, 92 CTLFLAG_RW, &suser_privileged, 0, "Make an exception for superuser"); 93 94 /* 95 * Exception: allow processes with a specific gid to be exempt from the 96 * policy. One sysctl enables this functionality; the other sets the 97 * exempt gid. 98 */ 99 static int specificgid_enabled = 0; 100 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid_enabled, 101 CTLFLAG_RW, &specificgid_enabled, 0, "Make an exception for credentials " 102 "with a specific gid as their real primary group id or group set"); 103 104 static gid_t specificgid = 0; 105 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid, CTLFLAG_RW, 106 &specificgid, 0, "Specific gid to be exempt from seeotheruids policy"); 107 108 static int 109 mac_seeotheruids_check(struct ucred *u1, struct ucred *u2) 110 { 111 112 if (!mac_seeotheruids_enabled) 113 return (0); 114 115 if (primarygroup_enabled) { 116 if (u1->cr_rgid == u2->cr_rgid) 117 return (0); 118 } 119 120 if (specificgid_enabled) { 121 if (u1->cr_rgid == specificgid || groupmember(specificgid, u1)) 122 return (0); 123 } 124 125 if (u1->cr_ruid == u2->cr_ruid) 126 return (0); 127 128 if (suser_privileged) { 129 if (suser_cred(u1, 0) == 0) 130 return (0); 131 } 132 133 return (ESRCH); 134 } 135 136 static int 137 mac_seeotheruids_check_cred_visible(struct ucred *u1, struct ucred *u2) 138 { 139 140 return (mac_seeotheruids_check(u1, u2)); 141 } 142 143 static int 144 mac_seeotheruids_check_proc_signal(struct ucred *cred, struct proc *proc, 145 int signum) 146 { 147 148 return (mac_seeotheruids_check(cred, proc->p_ucred)); 149 } 150 151 static int 152 mac_seeotheruids_check_proc_sched(struct ucred *cred, struct proc *proc) 153 { 154 155 return (mac_seeotheruids_check(cred, proc->p_ucred)); 156 } 157 158 static int 159 mac_seeotheruids_check_proc_debug(struct ucred *cred, struct proc *proc) 160 { 161 162 return (mac_seeotheruids_check(cred, proc->p_ucred)); 163 } 164 165 static int 166 mac_seeotheruids_check_socket_visible(struct ucred *cred, struct socket *socket, 167 struct label *socketlabel) 168 { 169 170 return (mac_seeotheruids_check(cred, socket->so_cred)); 171 } 172 173 static struct mac_policy_ops mac_seeotheruids_ops = 174 { 175 .mpo_check_cred_visible = mac_seeotheruids_check_cred_visible, 176 .mpo_check_proc_debug = mac_seeotheruids_check_proc_debug, 177 .mpo_check_proc_sched = mac_seeotheruids_check_proc_sched, 178 .mpo_check_proc_signal = mac_seeotheruids_check_proc_signal, 179 .mpo_check_socket_visible = mac_seeotheruids_check_socket_visible, 180 }; 181 182 MAC_POLICY_SET(&mac_seeotheruids_ops, mac_seeotheruids, 183 "TrustedBSD MAC/seeotheruids", MPC_LOADTIME_FLAG_UNLOADOK, NULL); 184