newgrp.c revision 1.1
1 /*- 2 * Copyright (c) 2007 The NetBSD Foundation, Inc. 3 * All rights reserved. 4 * 5 * This code is derived from software contributed to The NetBSD Foundation 6 * by Brian Ginsbach. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the NetBSD 19 * Foundation, Inc. and its contributors. 20 * 4. Neither the name of The NetBSD Foundation nor the names of its 21 * contributors may be used to endorse or promote products derived 22 * from this software without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 25 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 26 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 27 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 28 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 29 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 30 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 31 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 32 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 33 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 34 * POSSIBILITY OF SUCH DAMAGE. 35 */ 36 37 #include <sys/cdefs.h> 38 39 #ifndef lint 40 __RCSID("$NetBSD: newgrp.c,v 1.1 2007/06/21 14:09:24 ginsbach Exp $"); 41 #endif /* not lint */ 42 43 #include <sys/param.h> 44 #include <sys/types.h> 45 46 #include <err.h> 47 #include <grp.h> 48 #include <libgen.h> 49 #include <paths.h> 50 #include <pwd.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 #include <unistd.h> 55 56 #ifdef LOGIN_CAP 57 #include <login_cap.h> 58 #endif 59 60 int addgrp(gid_t); 61 gid_t newgrp(const char *, struct passwd *); 62 void usage(void); 63 64 int 65 main(int argc, char *argv[]) 66 { 67 extern char **environ; 68 struct passwd *pwd; 69 int c, lflag; 70 char *shell, sbuf[MAXPATHLEN + 2]; 71 uid_t uid; 72 #ifdef LOGIN_CAP 73 login_cap_t *lc; 74 u_int flags = LOGIN_SETUSER; 75 #endif 76 77 uid = getuid(); 78 pwd = getpwuid(uid); 79 if (pwd == NULL) 80 errx(1, "who are you?"); 81 82 #ifdef LOGIN_CAP 83 if ((lc = login_getclass(pwd->pw_class)) == NULL) 84 errx(1, "%s: unknown login class", pwd->pw_class); 85 #endif 86 87 lflag = 0; 88 while ((c = getopt(argc, argv, "-l")) != -1) { 89 switch (c) { 90 case '-': 91 case 'l': 92 if (lflag) 93 usage(); 94 lflag = 1; 95 break; 96 default: 97 usage(); 98 break; 99 } 100 } 101 102 argc -= optind; 103 argv += optind; 104 105 if (argc > 0) { 106 pwd->pw_gid = newgrp(*argv, pwd); 107 addgrp(pwd->pw_gid); 108 if (setgid(pwd->pw_gid) < 0) 109 err(1, "setgid"); 110 } else { 111 #ifdef LOGIN_CAP 112 flags |= LOGIN_SETGROUP; 113 #else 114 if (initgroups(pwd->pw_name, pwd->pw_gid) < 0) 115 err(1, "initgroups"); 116 if (setgid(pwd->pw_gid) < 0) 117 err(1, "setgid"); 118 #endif 119 } 120 121 #ifdef LOGIN_CAP 122 if (setusercontext(lc, pwd, uid, flags)) 123 err(1, "setusercontext"); 124 if (!lflag) 125 login_close(lc); 126 #else 127 if (setuid(pwd->pw_uid) < 0) 128 err(1, "setuid"); 129 #endif 130 131 if (*pwd->pw_shell == '\0') { 132 #ifdef TRUST_ENV_SHELL 133 shell = getenv("SHELL"); 134 if (shell != NULL) 135 pwd->pw_shell = shell; 136 else 137 #endif 138 pwd->pw_shell = _PATH_BSHELL; 139 } 140 141 shell = pwd->pw_shell; 142 143 if (lflag) { 144 char *term; 145 #ifdef KERBEROS 146 char *krbtkfile; 147 #endif 148 149 if (chdir(pwd->pw_dir) < 0) 150 warn("%s", pwd->pw_dir); 151 152 term = getenv("TERM"); 153 #ifdef KERBEROS 154 krbtkfile = getenv("KRBTKFILE"); 155 #endif 156 157 /* create an empty environment */ 158 if ((environ = malloc(sizeof(char *))) == NULL) 159 err(1, NULL); 160 environ[0] = NULL; 161 #ifdef LOGIN_CAP 162 if (setusercontext(lc, pwd, uid, LOGIN_SETENV|LOGIN_SETPATH)) 163 err(1, "setusercontext"); 164 login_close(lc); 165 #else 166 (void)setenv("PATH", _PATH_DEFPATH, 1); 167 #endif 168 if (term != NULL) 169 (void)setenv("TERM", term, 1); 170 #ifdef KERBEROS 171 if (krbtkfile != NULL) 172 (void)setenv("KRBTKFILE", krbtkfile, 1); 173 #endif 174 175 (void)setenv("LOGNAME", pwd->pw_name, 1); 176 (void)setenv("USER", pwd->pw_name, 1); 177 (void)setenv("HOME", pwd->pw_dir, 1); 178 (void)setenv("SHELL", pwd->pw_shell, 1); 179 180 sbuf[0] = '-'; 181 (void)strlcpy(sbuf + 1, basename(pwd->pw_shell), 182 sizeof(sbuf) - 1); 183 shell = sbuf; 184 } 185 186 execl(pwd->pw_shell, shell, NULL); 187 err(1, "%s", pwd->pw_shell); 188 } 189 190 gid_t 191 newgrp(const char *group, struct passwd *pwd) 192 { 193 struct group *grp; 194 char *ep, **p; 195 gid_t gid; 196 197 grp = getgrnam(group); 198 if (grp == NULL) { 199 if (*group != '-') { 200 gid = (gid_t)strtol(group, &ep, 10); 201 if (*ep == '\0') 202 grp = getgrgid(gid); 203 } 204 } 205 206 if (grp == NULL) { 207 warnx("%s: unknown group", group); 208 return getgid(); 209 } 210 211 if (pwd->pw_gid == grp->gr_gid || getuid() == 0) 212 return grp->gr_gid; 213 214 for (p = grp->gr_mem; *p == NULL; p++) 215 if (strcmp(*p, pwd->pw_name) == 0) 216 return grp->gr_gid; 217 218 if (*grp->gr_passwd != '\0') { 219 ep = getpass("Password:"); 220 if (strcmp(grp->gr_passwd, crypt(ep, grp->gr_passwd)) == 0) { 221 memset(p, '\0', _PASSWORD_LEN); 222 return grp->gr_gid; 223 } 224 memset(ep, '\0', _PASSWORD_LEN); 225 } 226 227 warnx("Sorry"); 228 return getgid(); 229 } 230 231 int 232 addgrp(gid_t group) 233 { 234 int i, ngroups, ngroupsmax, rval; 235 gid_t *groups; 236 237 rval = 0; 238 239 ngroupsmax = (int)sysconf(_SC_NGROUPS_MAX); 240 if (ngroupsmax < 0) 241 ngroupsmax = NGROUPS_MAX; 242 243 groups = malloc(ngroupsmax * sizeof(*groups)); 244 if (groups == NULL) 245 return -1; 246 247 ngroups = getgroups(ngroupsmax, groups); 248 if (ngroups < 0) { 249 free(groups); 250 err(1, "getgroups"); 251 return -1; 252 } 253 254 /* 255 * BSD based systems normally have the egid in the supplemental 256 * group list. 257 */ 258 #if (defined(BSD) && BSD >= 199306) 259 /* 260 * According to POSIX/XPG6: 261 * On system where the egid is normally in the supplemental group list 262 * (or whenever the old egid actually is in the supplemental group 263 * list): 264 * o If the new egid is in the supplemental group list, 265 * just change the egid. 266 * o If the new egid is not in the supplemental group list, 267 * add the new egid to the list if there is room. 268 */ 269 270 /* search for new egid in supplemental group list */ 271 for (i = 0; i < ngroups && groups[i] != group; i++) 272 continue; 273 274 /* add the new egid to the supplemental group list */ 275 if (i == ngroups && ngroups < ngroupsmax) { 276 groups[ngroups++] = group; 277 if (setgroups(ngroups, groups) < 0) { 278 warn("setgroups"); 279 rval = -1; 280 } 281 } 282 #else 283 /* 284 * According to POSIX/XPG6: 285 * On systems where the egid is not normally in the supplemental group 286 * list (or whenever the old egid is not in the supplemental group 287 * list): 288 * o If the new egid is in the supplemental group list, delete 289 * it from the list. 290 * o If the old egid is not in the supplemental group list, 291 * add the old egid to the list if there is room. 292 */ 293 294 /* search for new egid in supplemental group list */ 295 for (i = 0; i < ngroups && group[i] != group; i++) 296 continue; 297 298 /* remove new egid from supplemental group list */ 299 if (i != ngroup) { 300 for (--ngroups; i < ngroups; i++) 301 groups[i] = groups[i + 1]; 302 } 303 304 /* search for old egid in supplemental group list */ 305 for (i = 0; i < ngroups && groups[i] != egid; i++) 306 continue; 307 308 /* add old egid from supplemental group list */ 309 if (i == ngroups && ngroups < maxngroups) { 310 groups[ngroups++] = egid; 311 if (setgroups(ngroups, groups) < 0) { 312 warn("setgroups"); 313 rval = -1; 314 } 315 } 316 #endif 317 318 free(groups); 319 return rval; 320 } 321 322 void 323 usage() 324 { 325 326 (void)fprintf(stderr, "usage: %s [-l] [group]\n", getprogname()); 327 exit(1); 328 } 329
Indexes created Fri Oct 03 15:10:06 GMT 2025