1 /* 2 * $FreeBSD$ 3 * 4 * Copyright (c) 2011-2013, 2015, 2019 Juniper Networks, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 22 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/buf.h> 33 #include <sys/conf.h> 34 #include <sys/errno.h> 35 #include <sys/fcntl.h> 36 #include <sys/file.h> 37 #include <sys/filedesc.h> 38 #include <sys/ioccom.h> 39 #include <sys/jail.h> 40 #include <sys/kernel.h> 41 #include <sys/lock.h> 42 #include <sys/malloc.h> 43 #include <sys/mdioctl.h> 44 #include <sys/mount.h> 45 #include <sys/mutex.h> 46 #include <sys/namei.h> 47 #include <sys/priv.h> 48 #include <sys/proc.h> 49 #include <sys/queue.h> 50 #include <sys/vnode.h> 51 52 #include <security/mac_veriexec/mac_veriexec.h> 53 #include <security/mac_veriexec/mac_veriexec_internal.h> 54 55 #include "veriexec_ioctl.h" 56 57 /* 58 * We need a mutex while updating lists etc. 59 */ 60 extern struct mtx ve_mutex; 61 62 /* 63 * Handle the ioctl for the device 64 */ 65 static int 66 verifiedexecioctl(struct cdev *dev __unused, u_long cmd, caddr_t data, 67 int flags, struct thread *td) 68 { 69 struct nameidata nid; 70 struct vattr vattr; 71 struct verified_exec_label_params *lparams; 72 struct verified_exec_params *params; 73 int error = 0; 74 75 /* 76 * These commands are considered safe requests for anyone who has 77 * permission to access to device node. 78 */ 79 switch (cmd) { 80 case VERIEXEC_GETSTATE: 81 { 82 int *ip = (int *)data; 83 84 if (ip) 85 *ip = mac_veriexec_get_state(); 86 else 87 error = EINVAL; 88 89 return (error); 90 } 91 break; 92 default: 93 break; 94 } 95 96 /* 97 * Anything beyond this point is considered dangerous, so we need to 98 * only allow processes that have kmem write privs to do them. 99 * 100 * MAC/veriexec will grant kmem write privs to "trusted" processes. 101 */ 102 error = priv_check(td, PRIV_KMEM_WRITE); 103 if (error) 104 return (error); 105 106 lparams = (struct verified_exec_label_params *)data; 107 if (cmd == VERIEXEC_LABEL_LOAD) 108 params = &lparams->params; 109 else 110 params = (struct verified_exec_params *)data; 111 112 switch (cmd) { 113 case VERIEXEC_ACTIVE: 114 mtx_lock(&ve_mutex); 115 if (mac_veriexec_in_state(VERIEXEC_STATE_LOADED)) 116 mac_veriexec_set_state(VERIEXEC_STATE_ACTIVE); 117 else 118 error = EINVAL; 119 mtx_unlock(&ve_mutex); 120 break; 121 case VERIEXEC_DEBUG_ON: 122 mtx_lock(&ve_mutex); 123 { 124 int *ip = (int *)data; 125 126 mac_veriexec_debug++; 127 if (ip) { 128 if (*ip > 0) 129 mac_veriexec_debug = *ip; 130 *ip = mac_veriexec_debug; 131 } 132 } 133 mtx_unlock(&ve_mutex); 134 break; 135 case VERIEXEC_DEBUG_OFF: 136 mac_veriexec_debug = 0; 137 break; 138 case VERIEXEC_ENFORCE: 139 mtx_lock(&ve_mutex); 140 if (mac_veriexec_in_state(VERIEXEC_STATE_LOADED)) 141 mac_veriexec_set_state(VERIEXEC_STATE_ACTIVE | 142 VERIEXEC_STATE_ENFORCE); 143 else 144 error = EINVAL; 145 mtx_unlock(&ve_mutex); 146 break; 147 case VERIEXEC_GETVERSION: 148 { 149 int *ip = (int *)data; 150 151 if (ip) 152 *ip = MAC_VERIEXEC_VERSION; 153 else 154 error = EINVAL; 155 } 156 break; 157 case VERIEXEC_LOCK: 158 mtx_lock(&ve_mutex); 159 mac_veriexec_set_state(VERIEXEC_STATE_LOCKED); 160 mtx_unlock(&ve_mutex); 161 break; 162 case VERIEXEC_LOAD: 163 if (prison0.pr_securelevel > 0) 164 return (EPERM); /* no updates when secure */ 165 166 /* FALLTHROUGH */ 167 case VERIEXEC_LABEL_LOAD: 168 case VERIEXEC_SIGNED_LOAD: 169 /* 170 * If we use a loader that will only use a 171 * digitally signed hash list - which it verifies. 172 * We can load fingerprints provided veriexec is not locked. 173 */ 174 if (prison0.pr_securelevel > 0 && 175 !mac_veriexec_in_state(VERIEXEC_STATE_LOADED)) { 176 /* 177 * If securelevel has been raised and we 178 * do not have any fingerprints loaded, 179 * it would dangerous to do so now. 180 */ 181 return (EPERM); 182 } 183 if (mac_veriexec_in_state(VERIEXEC_STATE_LOCKED)) 184 error = EPERM; 185 else { 186 size_t labellen = 0; 187 int flags = FREAD; 188 int override = (cmd != VERIEXEC_LOAD); 189 190 /* 191 * Get the attributes for the file name passed 192 * stash the file's device id and inode number 193 * along with it's fingerprint in a list for 194 * exec to use later. 195 */ 196 /* 197 * FreeBSD seems to copy the args to kernel space 198 */ 199 NDINIT(&nid, LOOKUP, FOLLOW, UIO_SYSSPACE, 200 params->file, td); 201 if ((error = vn_open(&nid, &flags, 0, NULL)) != 0) 202 return (error); 203 204 error = VOP_GETATTR(nid.ni_vp, &vattr, td->td_ucred); 205 if (error != 0) { 206 mac_veriexec_set_fingerprint_status(nid.ni_vp, 207 FINGERPRINT_INVALID); 208 VOP_UNLOCK(nid.ni_vp); 209 (void) vn_close(nid.ni_vp, FREAD, td->td_ucred, 210 td); 211 return (error); 212 } 213 if (override) { 214 /* 215 * If the file is on a "verified" filesystem 216 * someone may be playing games. 217 */ 218 if ((nid.ni_vp->v_mount->mnt_flag & 219 MNT_VERIFIED) != 0) 220 override = 0; 221 } 222 223 /* 224 * invalidate the node fingerprint status 225 * which will have been set in the vn_open 226 * and would always be FINGERPRINT_NOTFOUND 227 */ 228 mac_veriexec_set_fingerprint_status(nid.ni_vp, 229 FINGERPRINT_INVALID); 230 VOP_UNLOCK(nid.ni_vp); 231 (void) vn_close(nid.ni_vp, FREAD, td->td_ucred, td); 232 if (params->flags & VERIEXEC_LABEL) 233 labellen = strnlen(lparams->label, 234 sizeof(lparams->label) - 1) + 1; 235 236 mtx_lock(&ve_mutex); 237 error = mac_veriexec_metadata_add_file( 238 ((params->flags & VERIEXEC_FILE) != 0), 239 vattr.va_fsid, vattr.va_fileid, vattr.va_gen, 240 params->fingerprint, 241 (params->flags & VERIEXEC_LABEL) ? 242 lparams->label : NULL, labellen, 243 params->flags, params->fp_type, override); 244 245 mac_veriexec_set_state(VERIEXEC_STATE_LOADED); 246 mtx_unlock(&ve_mutex); 247 } 248 break; 249 default: 250 error = ENODEV; 251 } 252 return (error); 253 } 254 255 struct cdevsw veriexec_cdevsw = { 256 .d_version = D_VERSION, 257 .d_ioctl = verifiedexecioctl, 258 .d_name = "veriexec", 259 }; 260 261 static void 262 veriexec_drvinit(void *unused __unused) 263 { 264 265 make_dev(&veriexec_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600, "veriexec"); 266 } 267 268 SYSINIT(veriexec, SI_SUB_PSEUDO, SI_ORDER_ANY, veriexec_drvinit, NULL); 269 MODULE_DEPEND(veriexec, mac_veriexec, 1, 1, 1); 270