1 /* $OpenBSD: doas.c,v 1.4 2015/07/16 21:57:54 deraadt Exp $ */
3 * Copyright (c) 2015 Ted Unangst <tedu@openbsd.org>
5 * Permission to use, copy, modify, and distribute this software for any
6 * purpose with or without fee is hereby granted, provided that the above
7 * copyright notice and this permission notice appear in all copies.
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 #include <sys/types.h>
20 #include <login_cap.h>
36 fprintf(stderr, "usage: doas [-u user] command [args]\n");
41 arraylen(const char **arr)
52 parseuid(const char *s, uid_t *uid)
57 if ((pw = getpwnam(s)) != NULL) {
61 *uid = strtonum(s, 0, UID_MAX, &errstr);
68 uidcheck(const char *s, uid_t desired)
72 if (parseuid(s, &uid) != 0)
80 strtogid(const char *s)
86 if ((gr = getgrnam(s)) != NULL)
88 gid = strtonum(s, 0, GID_MAX, &errstr);
95 match(uid_t uid, gid_t *groups, int ngroups, uid_t target, const char *cmd,
100 if (r->ident[0] == ':') {
101 gid_t rgid = strtogid(r->ident + 1);
104 for (i = 0; i < ngroups; i++) {
105 if (rgid == groups[i])
111 if (uidcheck(r->ident, uid) != 0)
114 if (r->target && uidcheck(r->target, target) != 0)
116 if (r->cmd && strcmp(r->cmd, cmd) != 0)
122 permit(uid_t uid, gid_t *groups, int ngroups, struct rule **lastr,
123 uid_t target, const char *cmd)
128 for (i = 0; i < nrules; i++) {
129 if (match(uid, groups, ngroups, target, cmd, rules[i]))
134 return (*lastr)->action == PERMIT;
138 parseconfig(const char *filename)
141 extern int yyparse(void);
143 yyfp = fopen(filename, "r");
145 fprintf(stderr, "doas is not enabled.\n");
153 copyenvhelper(const char **oldenvp, const char **safeset, int nsafe,
157 for (i = 0; i < nsafe; i++) {
158 const char **oe = oldenvp;
160 size_t len = strlen(safeset[i]);
161 if (strncmp(*oe, safeset[i], len) == 0 &&
163 if (!(envp[ei++] = strdup(*oe)))
174 copyenv(const char **oldenvp, struct rule *rule)
176 const char *safeset[] = {
177 "DISPLAY", "HOME", "LOGNAME", "MAIL", "SHELL",
178 "PATH", "TERM", "USER", "USERNAME",
188 if ((rule->options & KEEPENV) && !rule->envlist) {
189 j = arraylen(oldenvp);
190 envp = reallocarray(NULL, j + 1, sizeof(char *));
192 err(1, "reallocarray");
193 for (i = 0; i < j; i++) {
194 if (!(envp[i] = strdup(oldenvp[i])))
201 nsafe = arraylen(safeset);
202 if ((extra = rule->envlist)) {
203 nextras = arraylen(extra);
204 for (i = 0; i < nsafe; i++) {
205 for (j = 0; j < nextras; j++) {
206 if (strcmp(extra[j], safeset[i]) == 0) {
207 extra[j--] = extra[nextras--];
208 extra[nextras] = NULL;
214 envp = reallocarray(NULL, nsafe + nextras + 1, sizeof(char *));
216 err(1, "can't allocate new environment");
219 ei = copyenvhelper(oldenvp, safeset, nsafe, envp, ei);
220 ei = copyenvhelper(oldenvp, rule->envlist, nextras, envp, ei);
229 fprintf(stderr, "Permission denied\n");
234 main(int argc, char **argv, char **envp)
238 uid_t uid, target = 0;
239 gid_t groups[NGROUPS_MAX + 1];
245 const char *safepath = "/bin:/sbin:/usr/bin:/usr/sbin:"
246 "/usr/local/bin:/usr/local/sbin";
248 parseconfig("/etc/doas.conf");
250 while ((ch = getopt(argc, argv, "u:")) != -1) {
253 if (parseuid(optarg, &target) != 0)
254 errx(1, "unknown user");
268 strlcpy(cmdline, argv[0], sizeof(cmdline));
269 for (i = 1; i < argc; i++) {
270 strlcat(cmdline, " ", sizeof(cmdline));
271 strlcat(cmdline, argv[i], sizeof(cmdline));
277 err(1, "getpwuid failed");
278 strlcpy(myname, pw->pw_name, sizeof(myname));
279 ngroups = getgroups(NGROUPS_MAX, groups);
281 err(1, "can't get groups");
282 groups[ngroups++] = getgid();
284 if (!permit(uid, groups, ngroups, &rule, target, cmd)) {
285 syslog(LOG_AUTHPRIV | LOG_NOTICE,
286 "failed command for %s: %s", myname, cmdline);
290 if (!(rule->options & NOPASS)) {
291 if (!auth_userokay(myname, NULL, NULL, NULL)) {
292 syslog(LOG_AUTHPRIV | LOG_NOTICE,
293 "failed password for %s", myname);
297 envp = copyenv((const char **)envp, rule);
299 pw = getpwuid(target);
301 errx(1, "no passwd entry for target");
302 if (setusercontext(NULL, pw, target, LOGIN_SETGROUP |
303 LOGIN_SETPRIORITY | LOGIN_SETRESOURCES | LOGIN_SETUMASK |
305 errx(1, "failed to set user context for target");
307 syslog(LOG_AUTHPRIV | LOG_INFO, "%s ran command as %s: %s",
308 myname, pw->pw_name, cmdline);
309 setenv("PATH", safepath, 1);
310 execvpe(cmd, argv, envp);