1 /* $OpenBSD: doas.c,v 1.8 2015/07/18 06:33:23 nicm 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.
18 #include <sys/types.h>
22 #include <login_cap.h>
38 fprintf(stderr, "usage: doas [-s] [-u user] command [args]\n");
43 arraylen(const char **arr)
55 parseuid(const char *s, uid_t *uid)
60 if ((pw = getpwnam(s)) != NULL) {
64 *uid = strtonum(s, 0, UID_MAX, &errstr);
71 uidcheck(const char *s, uid_t desired)
75 if (parseuid(s, &uid) != 0)
83 strtogid(const char *s)
89 if ((gr = getgrnam(s)) != NULL)
91 gid = strtonum(s, 0, GID_MAX, &errstr);
98 match(uid_t uid, gid_t *groups, int ngroups, uid_t target, const char *cmd,
103 if (r->ident[0] == ':') {
104 gid_t rgid = strtogid(r->ident + 1);
107 for (i = 0; i < ngroups; i++) {
108 if (rgid == groups[i])
114 if (uidcheck(r->ident, uid) != 0)
117 if (r->target && uidcheck(r->target, target) != 0)
119 if (r->cmd && strcmp(r->cmd, cmd) != 0)
125 permit(uid_t uid, gid_t *groups, int ngroups, struct rule **lastr,
126 uid_t target, const char *cmd)
131 for (i = 0; i < nrules; i++) {
132 if (match(uid, groups, ngroups, target, cmd, rules[i]))
137 return (*lastr)->action == PERMIT;
141 parseconfig(const char *filename)
144 extern int yyparse(void);
147 yyfp = fopen(filename, "r");
149 fprintf(stderr, "doas is not enabled.\n");
153 if (fstat(fileno(yyfp), &sb) != 0)
154 err(1, "fstat(\"%s\")", filename);
155 if ((sb.st_mode & (S_IWGRP|S_IWOTH)) != 0)
156 errx(1, "%s is writable by group or other", filename);
158 errx(1, "%s is not owned by root", filename);
165 copyenvhelper(const char **oldenvp, const char **safeset, int nsafe,
170 for (i = 0; i < nsafe; i++) {
171 const char **oe = oldenvp;
173 size_t len = strlen(safeset[i]);
174 if (strncmp(*oe, safeset[i], len) == 0 &&
176 if (!(envp[ei++] = strdup(*oe)))
187 copyenv(const char **oldenvp, struct rule *rule)
189 const char *safeset[] = {
190 "DISPLAY", "HOME", "LOGNAME", "MAIL", "SHELL",
191 "PATH", "TERM", "USER", "USERNAME",
201 if ((rule->options & KEEPENV) && !rule->envlist) {
202 j = arraylen(oldenvp);
203 envp = reallocarray(NULL, j + 1, sizeof(char *));
205 err(1, "reallocarray");
206 for (i = 0; i < j; i++) {
207 if (!(envp[i] = strdup(oldenvp[i])))
214 nsafe = arraylen(safeset);
215 if ((extra = rule->envlist)) {
216 nextras = arraylen(extra);
217 for (i = 0; i < nsafe; i++) {
218 for (j = 0; j < nextras; j++) {
219 if (strcmp(extra[j], safeset[i]) == 0) {
220 extra[j--] = extra[nextras--];
221 extra[nextras] = NULL;
227 envp = reallocarray(NULL, nsafe + nextras + 1, sizeof(char *));
229 err(1, "can't allocate new environment");
232 ei = copyenvhelper(oldenvp, safeset, nsafe, envp, ei);
233 ei = copyenvhelper(oldenvp, rule->envlist, nextras, envp, ei);
242 fprintf(stderr, "Permission denied\n");
247 main(int argc, char **argv, char **envp)
249 const char *safepath = "/bin:/sbin:/usr/bin:/usr/sbin:"
250 "/usr/local/bin:/usr/local/sbin";
251 char *shargv[] = { NULL, NULL };
254 char cmdline[LINE_MAX];
255 char myname[_PW_NAME_LEN + 1];
260 gid_t groups[NGROUPS_MAX + 1];
265 parseconfig("/etc/doas.conf");
267 while ((ch = getopt(argc, argv, "su:")) != -1) {
270 if (parseuid(optarg, &target) != 0)
271 errx(1, "unknown user");
284 if ((!sflag && !argc) || (sflag && argc))
290 err(1, "getpwuid failed");
291 if (strlcpy(myname, pw->pw_name, sizeof(myname)) >= sizeof(myname))
292 errx(1, "pw_name too long");
293 ngroups = getgroups(NGROUPS_MAX, groups);
295 err(1, "can't get groups");
296 groups[ngroups++] = getgid();
299 sh = getenv("SHELL");
300 if (sh == NULL || *sh == '\0')
301 shargv[0] = pw->pw_shell;
309 if (strlcpy(cmdline, argv[0], sizeof(cmdline)) >= sizeof(cmdline))
310 errx(1, "command line too long");
311 for (i = 1; i < argc; i++) {
312 if (strlcat(cmdline, " ", sizeof(cmdline)) >= sizeof(cmdline))
313 errx(1, "command line too long");
314 if (strlcat(cmdline, argv[i], sizeof(cmdline)) >= sizeof(cmdline))
315 errx(1, "command line too long");
318 if (!permit(uid, groups, ngroups, &rule, target, cmd)) {
319 syslog(LOG_AUTHPRIV | LOG_NOTICE,
320 "failed command for %s: %s", myname, cmdline);
324 if (!(rule->options & NOPASS)) {
325 if (!auth_userokay(myname, NULL, NULL, NULL)) {
326 syslog(LOG_AUTHPRIV | LOG_NOTICE,
327 "failed password for %s", myname);
331 envp = copyenv((const char **)envp, rule);
333 pw = getpwuid(target);
335 errx(1, "no passwd entry for target");
336 if (setusercontext(NULL, pw, target, LOGIN_SETGROUP |
337 LOGIN_SETPRIORITY | LOGIN_SETRESOURCES | LOGIN_SETUMASK |
339 errx(1, "failed to set user context for target");
341 syslog(LOG_AUTHPRIV | LOG_INFO, "%s ran command as %s: %s",
342 myname, pw->pw_name, cmdline);
343 if (setenv("PATH", safepath, 1) == -1)
344 err(1, "failed to set PATH '%s'", safepath);
345 execvpe(cmd, argv, envp);