1 /*- 2 * Copyright (c) 1999-2002, 2007 Robert N. M. Watson 3 * Copyright (c) 2001-2002 Networks Associates Technology, Inc. 4 * Copyright (c) 2006 SPARTA, Inc. 5 * All rights reserved. 6 * 7 * This software was developed by Robert Watson for the TrustedBSD Project. 8 * 9 * This software was developed for the FreeBSD Project in part by Network 10 * Associates Laboratories, the Security Research Division of Network 11 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), 12 * as part of the DARPA CHATS research program. 13 * 14 * This software was enhanced by SPARTA ISSO under SPAWAR contract 15 * N66001-04-C-6019 ("SEFOS"). 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notice, this list of conditions and the following disclaimer. 22 * 2. Redistributions in binary form must reproduce the above copyright 23 * notice, this list of conditions and the following disclaimer in the 24 * documentation and/or other materials provided with the distribution. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 /* 40 * Developed by the TrustedBSD Project. 41 * 42 * Prevent processes owned by a particular uid from seeing various transient 43 * kernel objects associated with other uids. 44 */ 45 46 #include <sys/param.h> 47 #include <sys/kernel.h> 48 #include <sys/module.h> 49 #include <sys/priv.h> 50 #include <sys/proc.h> 51 #include <sys/systm.h> 52 #include <sys/socket.h> 53 #include <sys/socketvar.h> 54 #include <sys/sysctl.h> 55 56 #include <net/route.h> 57 #include <netinet/in.h> 58 #include <netinet/in_pcb.h> 59 60 #include <security/mac/mac_policy.h> 61 62 static SYSCTL_NODE(_security_mac, OID_AUTO, seeotheruids, 63 CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 64 "TrustedBSD mac_seeotheruids policy controls"); 65 66 static int seeotheruids_enabled = 1; 67 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, enabled, CTLFLAG_RW, 68 &seeotheruids_enabled, 0, "Enforce seeotheruids policy"); 69 70 /* 71 * Exception: allow credentials to be aware of other credentials with the 72 * same primary gid. 73 */ 74 static int primarygroup_enabled = 0; 75 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, primarygroup_enabled, 76 CTLFLAG_RW, &primarygroup_enabled, 0, "Make an exception for credentials " 77 "with the same real primary group id"); 78 79 /* 80 * Exception: allow the root user to be aware of other credentials by virtue 81 * of privilege. 82 */ 83 static int suser_privileged = 1; 84 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, suser_privileged, 85 CTLFLAG_RW, &suser_privileged, 0, "Make an exception for superuser"); 86 87 /* 88 * Exception: allow processes with a specific gid to be exempt from the 89 * policy. One sysctl enables this functionality; the other sets the 90 * exempt gid. 91 */ 92 static int specificgid_enabled = 0; 93 SYSCTL_INT(_security_mac_seeotheruids, OID_AUTO, specificgid_enabled, 94 CTLFLAG_RW, &specificgid_enabled, 0, "Make an exception for credentials " 95 "with a specific gid as their real primary group id or group set"); 96 97 static gid_t specificgid = 0; 98 SYSCTL_UINT(_security_mac_seeotheruids, OID_AUTO, specificgid, CTLFLAG_RW, 99 &specificgid, 0, "Specific gid to be exempt from seeotheruids policy"); 100 101 static int 102 seeotheruids_check(struct ucred *cr1, struct ucred *cr2) 103 { 104 105 if (!seeotheruids_enabled) 106 return (0); 107 108 if (primarygroup_enabled) { 109 if (cr1->cr_rgid == cr2->cr_rgid) 110 return (0); 111 } 112 113 if (specificgid_enabled) { 114 if (cr1->cr_rgid == specificgid || 115 groupmember(specificgid, cr1)) 116 return (0); 117 } 118 119 if (cr1->cr_ruid == cr2->cr_ruid) 120 return (0); 121 122 if (suser_privileged) { 123 if (priv_check_cred(cr1, PRIV_SEEOTHERUIDS) == 0) 124 return (0); 125 } 126 127 return (ESRCH); 128 } 129 130 static int 131 seeotheruids_proc_check_debug(struct ucred *cred, struct proc *p) 132 { 133 134 return (seeotheruids_check(cred, p->p_ucred)); 135 } 136 137 static int 138 seeotheruids_proc_check_sched(struct ucred *cred, struct proc *p) 139 { 140 141 return (seeotheruids_check(cred, p->p_ucred)); 142 } 143 144 static int 145 seeotheruids_proc_check_signal(struct ucred *cred, struct proc *p, 146 int signum) 147 { 148 149 return (seeotheruids_check(cred, p->p_ucred)); 150 } 151 152 static int 153 seeotheruids_cred_check_visible(struct ucred *cr1, struct ucred *cr2) 154 { 155 156 return (seeotheruids_check(cr1, cr2)); 157 } 158 159 static int 160 seeotheruids_inpcb_check_visible(struct ucred *cred, struct inpcb *inp, 161 struct label *inplabel) 162 { 163 164 return (seeotheruids_check(cred, inp->inp_cred)); 165 } 166 167 static int 168 seeotheruids_socket_check_visible(struct ucred *cred, struct socket *so, 169 struct label *solabel) 170 { 171 172 return (seeotheruids_check(cred, so->so_cred)); 173 } 174 175 static struct mac_policy_ops seeotheruids_ops = 176 { 177 .mpo_proc_check_debug = seeotheruids_proc_check_debug, 178 .mpo_proc_check_sched = seeotheruids_proc_check_sched, 179 .mpo_proc_check_signal = seeotheruids_proc_check_signal, 180 .mpo_cred_check_visible = seeotheruids_cred_check_visible, 181 .mpo_inpcb_check_visible = seeotheruids_inpcb_check_visible, 182 .mpo_socket_check_visible = seeotheruids_socket_check_visible, 183 }; 184 185 MAC_POLICY_SET(&seeotheruids_ops, mac_seeotheruids, 186 "TrustedBSD MAC/seeotheruids", MPC_LOADTIME_FLAG_UNLOADOK, NULL); 187