1 /*- 2 * Copyright (c) 2003 Mike Barcroft <mike@FreeBSD.org> 3 * Copyright (c) 2008 Bjoern A. Zeeb <bz@FreeBSD.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30 #include <sys/param.h> 31 #include <sys/jail.h> 32 #include <sys/sysctl.h> 33 34 #include <netinet/in.h> 35 36 #include <err.h> 37 #include <errno.h> 38 #include <login_cap.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <pwd.h> 43 #include <unistd.h> 44 45 static void usage(void); 46 47 #ifdef SUPPORT_OLD_XPRISON 48 static 49 char *lookup_xprison_v1(void *p, char *end, int *id) 50 { 51 struct xprison_v1 *xp; 52 53 if (id == NULL) 54 errx(1, "Internal error. Invalid ID pointer."); 55 56 if ((char *)p + sizeof(struct xprison_v1) > end) 57 errx(1, "Invalid length for jail"); 58 59 xp = (struct xprison_v1 *)p; 60 61 *id = xp->pr_id; 62 return ((char *)(xp + 1)); 63 } 64 #endif 65 66 static 67 char *lookup_xprison_v3(void *p, char *end, int *id, char *jailname) 68 { 69 struct xprison *xp; 70 char *q; 71 int ok; 72 73 if (id == NULL) 74 errx(1, "Internal error. Invalid ID pointer."); 75 76 if ((char *)p + sizeof(struct xprison) > end) 77 errx(1, "Invalid length for jail"); 78 79 xp = (struct xprison *)p; 80 ok = 1; 81 82 /* Jail state and name. */ 83 if (xp->pr_state < 0 || xp->pr_state >= 84 (int)((sizeof(prison_states) / sizeof(struct prison_state)))) 85 errx(1, "Invalid jail state."); 86 else if (xp->pr_state != PRISON_STATE_ALIVE) 87 ok = 0; 88 if (jailname != NULL) { 89 if (xp->pr_name[0] == '\0') 90 ok = 0; 91 else if (strcmp(jailname, xp->pr_name) != 0) 92 ok = 0; 93 } 94 95 q = (char *)(xp + 1); 96 /* IPv4 addresses. */ 97 q += (xp->pr_ip4s * sizeof(struct in_addr)); 98 if ((char *)q > end) 99 errx(1, "Invalid length for jail"); 100 /* IPv6 addresses. */ 101 q += (xp->pr_ip6s * sizeof(struct in6_addr)); 102 if ((char *)q > end) 103 errx(1, "Invalid length for jail"); 104 105 if (ok) 106 *id = xp->pr_id; 107 return (q); 108 } 109 110 static int 111 lookup_jail(int jid, char *jailname) 112 { 113 size_t i, j, len; 114 void *p, *q; 115 int version, id, xid, count; 116 117 if (sysctlbyname("security.jail.list", NULL, &len, NULL, 0) == -1) 118 err(1, "sysctlbyname(): security.jail.list"); 119 120 j = len; 121 for (i = 0; i < 4; i++) { 122 if (len == 0) 123 return (-1); 124 p = q = malloc(len); 125 if (p == NULL) 126 err(1, "malloc()"); 127 128 if (sysctlbyname("security.jail.list", q, &len, NULL, 0) == -1) { 129 if (errno == ENOMEM) { 130 free(p); 131 p = NULL; 132 len += j; 133 continue; 134 } 135 err(1, "sysctlbyname(): security.jail.list"); 136 } 137 break; 138 } 139 if (p == NULL) 140 err(1, "sysctlbyname(): security.jail.list"); 141 if (len < sizeof(int)) 142 errx(1, "This is no prison. Kernel and userland out of sync?"); 143 version = *(int *)p; 144 if (version > XPRISON_VERSION) 145 errx(1, "Sci-Fi prison. Kernel/userland out of sync?"); 146 147 count = 0; 148 xid = -1; 149 for (; q != NULL && (char *)q + sizeof(int) < (char *)p + len;) { 150 version = *(int *)q; 151 if (version > XPRISON_VERSION) 152 errx(1, "Sci-Fi prison. Kernel/userland out of sync?"); 153 id = -1; 154 switch (version) { 155 #ifdef SUPPORT_OLD_XPRISON 156 case 1: 157 if (jailname != NULL) 158 errx(1, "Version 1 prisons did not " 159 "support jail names."); 160 q = lookup_xprison_v1(q, (char *)p + len, &id); 161 break; 162 case 2: 163 errx(1, "Version 2 was used by multi-IPv4 jail " 164 "implementations that never made it into the " 165 "official kernel."); 166 /* NOTREACHED */ 167 break; 168 #endif 169 case 3: 170 q = lookup_xprison_v3(q, (char *)p + len, &id, jailname); 171 break; 172 default: 173 errx(1, "Prison unknown. Kernel/userland out of sync?"); 174 /* NOTREACHED */ 175 break; 176 } 177 /* Possible match; see if we have a jail ID to match as well. */ 178 if (id > 0 && (jid <= 0 || id == jid)) { 179 xid = id; 180 count++; 181 } 182 } 183 184 free(p); 185 186 if (count == 1) 187 return (xid); 188 else if (count > 1) 189 errx(1, "Could not uniquely identify the jail."); 190 else 191 return (-1); 192 } 193 194 #define GET_USER_INFO do { \ 195 pwd = getpwnam(username); \ 196 if (pwd == NULL) { \ 197 if (errno) \ 198 err(1, "getpwnam: %s", username); \ 199 else \ 200 errx(1, "%s: no such user", username); \ 201 } \ 202 lcap = login_getpwclass(pwd); \ 203 if (lcap == NULL) \ 204 err(1, "getpwclass: %s", username); \ 205 ngroups = NGROUPS; \ 206 if (getgrouplist(username, pwd->pw_gid, groups, &ngroups) != 0) \ 207 err(1, "getgrouplist: %s", username); \ 208 } while (0) 209 210 int 211 main(int argc, char *argv[]) 212 { 213 int jid; 214 login_cap_t *lcap = NULL; 215 struct passwd *pwd = NULL; 216 gid_t groups[NGROUPS]; 217 int ch, ngroups, uflag, Uflag; 218 char *jailname, *username; 219 220 ch = uflag = Uflag = 0; 221 jailname = username = NULL; 222 jid = -1; 223 224 while ((ch = getopt(argc, argv, "i:n:u:U:")) != -1) { 225 switch (ch) { 226 case 'n': 227 jailname = optarg; 228 break; 229 case 'u': 230 username = optarg; 231 uflag = 1; 232 break; 233 case 'U': 234 username = optarg; 235 Uflag = 1; 236 break; 237 default: 238 usage(); 239 } 240 } 241 argc -= optind; 242 argv += optind; 243 if (argc < 2) 244 usage(); 245 if (strlen(argv[0]) > 0) { 246 jid = (int)strtol(argv[0], NULL, 10); 247 if (errno) 248 err(1, "Unable to parse jail ID."); 249 } 250 if (jid <= 0 && jailname == NULL) { 251 fprintf(stderr, "Neither jail ID nor jail name given.\n"); 252 usage(); 253 } 254 if (uflag && Uflag) 255 usage(); 256 if (uflag) 257 GET_USER_INFO; 258 jid = lookup_jail(jid, jailname); 259 if (jid <= 0) 260 errx(1, "Cannot identify jail."); 261 if (jail_attach(jid) == -1) 262 err(1, "jail_attach(): %d", jid); 263 if (chdir("/") == -1) 264 err(1, "chdir(): /"); 265 if (username != NULL) { 266 if (Uflag) 267 GET_USER_INFO; 268 if (setgroups(ngroups, groups) != 0) 269 err(1, "setgroups"); 270 if (setgid(pwd->pw_gid) != 0) 271 err(1, "setgid"); 272 if (setusercontext(lcap, pwd, pwd->pw_uid, 273 LOGIN_SETALL & ~LOGIN_SETGROUP & ~LOGIN_SETLOGIN) != 0) 274 err(1, "setusercontext"); 275 login_close(lcap); 276 } 277 if (execvp(argv[1], argv + 1) == -1) 278 err(1, "execvp(): %s", argv[1]); 279 exit(0); 280 } 281 282 static void 283 usage(void) 284 { 285 286 fprintf(stderr, "%s%s\n", 287 "usage: jexec [-u username | -U username]", 288 " [-n jailname] jid command ..."); 289 exit(1); 290 } 291