-/* $OpenBSD: doas.c,v 1.7 2015/07/18 00:19:38 doug Exp $ */
+/* $OpenBSD: doas.c,v 1.52 2016/04/28 04:48:56 tedu Exp $ */
/*
* Copyright (c) 2015 Ted Unangst <tedu@openbsd.org>
*
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
+#include "config.h"
+
#include <sys/types.h>
#include <sys/stat.h>
+#include <sys/ioctl.h>
#include <limits.h>
+#ifdef HAVE_LOGIN_CAP_H
#include <login_cap.h>
-#include <bsd_auth.h>
+#endif
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <pwd.h>
#include <grp.h>
#include <syslog.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <time.h>
+#include "openbsd.h"
#include "doas.h"
static void __dead
usage(void)
{
- fprintf(stderr, "usage: doas [-s] [-u user] command [args]\n");
+ fprintf(stderr, "usage: doas [-Lns] [-C config] [-u user]"
+ " command [args]\n");
exit(1);
}
-size_t
-arraylen(const char **arr)
-{
- size_t cnt = 0;
- while (*arr) {
- cnt++;
- arr++;
- }
- return cnt;
-}
-
static int
parseuid(const char *s, uid_t *uid)
{
if ((pw = getpwnam(s)) != NULL) {
*uid = pw->pw_uid;
+ if (*uid == UID_MAX)
+ return -1;
return 0;
}
- *uid = strtonum(s, 0, UID_MAX, &errstr);
+ *uid = strtonum(s, 0, UID_MAX - 1, &errstr);
if (errstr)
return -1;
return 0;
return 0;
}
-static gid_t
-strtogid(const char *s)
+static int
+parsegid(const char *s, gid_t *gid)
{
struct group *gr;
const char *errstr;
- gid_t gid;
- if ((gr = getgrnam(s)) != NULL)
- return gr->gr_gid;
- gid = strtonum(s, 0, GID_MAX, &errstr);
+ if ((gr = getgrnam(s)) != NULL) {
+ *gid = gr->gr_gid;
+ if (*gid == GID_MAX)
+ return -1;
+ return 0;
+ }
+ *gid = strtonum(s, 0, GID_MAX - 1, &errstr);
if (errstr)
return -1;
- return gid;
+ return 0;
}
static int
match(uid_t uid, gid_t *groups, int ngroups, uid_t target, const char *cmd,
- struct rule *r)
+ const char **cmdargs, struct rule *r)
{
int i;
if (r->ident[0] == ':') {
- gid_t rgid = strtogid(r->ident + 1);
- if (rgid == -1)
+ gid_t rgid;
+ if (parsegid(r->ident + 1, &rgid) == -1)
return 0;
for (i = 0; i < ngroups; i++) {
if (rgid == groups[i])
}
if (r->target && uidcheck(r->target, target) != 0)
return 0;
- if (r->cmd && strcmp(r->cmd, cmd) != 0)
- return 0;
+ if (r->cmd) {
+ if (strcmp(r->cmd, cmd))
+ return 0;
+ if (r->cmdargs) {
+ /* if arguments were given, they should match explicitly */
+ for (i = 0; r->cmdargs[i]; i++) {
+ if (!cmdargs[i])
+ return 0;
+ if (strcmp(r->cmdargs[i], cmdargs[i]))
+ return 0;
+ }
+ if (cmdargs[i])
+ return 0;
+ }
+ }
return 1;
}
static int
-permit(uid_t uid, gid_t *groups, int ngroups, struct rule **lastr,
- uid_t target, const char *cmd)
+permit(uid_t uid, gid_t *groups, int ngroups, const struct rule **lastr,
+ uid_t target, const char *cmd, const char **cmdargs)
{
- int i;
+ size_t i;
*lastr = NULL;
for (i = 0; i < nrules; i++) {
- if (match(uid, groups, ngroups, target, cmd, rules[i]))
+ if (match(uid, groups, ngroups, target, cmd,
+ cmdargs, rules[i]))
*lastr = rules[i];
}
if (!*lastr)
}
static void
-parseconfig(const char *filename)
+parseconfig(const char *filename, int checkperms)
{
extern FILE *yyfp;
extern int yyparse(void);
struct stat sb;
yyfp = fopen(filename, "r");
- if (!yyfp) {
- fprintf(stderr, "doas is not enabled.\n");
- exit(1);
+ if (!yyfp)
+ err(1, checkperms ? "doas is not enabled, %s" :
+ "could not open config file %s", filename);
+
+ if (checkperms) {
+ if (fstat(fileno(yyfp), &sb) != 0)
+ err(1, "fstat(\"%s\")", filename);
+ if ((sb.st_mode & (S_IWGRP|S_IWOTH)) != 0)
+ errx(1, "%s is writable by group or other", filename);
+ if (sb.st_uid != 0)
+ errx(1, "%s is not owned by root", filename);
}
- if (fstat(fileno(yyfp), &sb) != 0)
- err(1, "fstat(\"%s\")", filename);
- if ((sb.st_mode & (S_IWGRP|S_IWOTH)) != 0)
- errx(1, "%s is writable by group or other", filename);
- if (sb.st_uid != 0)
- errx(1, "%s is not owned by root", filename);
-
yyparse();
fclose(yyfp);
+ if (parse_errors)
+ exit(1);
}
-static int
-copyenvhelper(const char **oldenvp, const char **safeset, int nsafe,
- char **envp, int ei)
+static void __dead
+checkconfig(const char *confpath, int argc, char **argv,
+ uid_t uid, gid_t *groups, int ngroups, uid_t target)
{
- int i;
- for (i = 0; i < nsafe; i++) {
- const char **oe = oldenvp;
- while (*oe) {
- size_t len = strlen(safeset[i]);
- if (strncmp(*oe, safeset[i], len) == 0 &&
- (*oe)[len] == '=') {
- if (!(envp[ei++] = strdup(*oe)))
- err(1, "strdup");
- break;
- }
- oe++;
- }
+ const struct rule *rule;
+
+ if (setresuid(uid, uid, uid) != 0)
+ err(1, "setresuid");
+
+ parseconfig(confpath, 0);
+ if (!argc)
+ exit(0);
+
+ if (permit(uid, groups, ngroups, &rule, target, argv[0],
+ (const char **)argv + 1)) {
+ printf("permit%s\n", (rule->options & NOPASS) ? " nopass" : "");
+ exit(0);
+ } else {
+ printf("deny\n");
+ exit(1);
}
- return ei;
}
-static char **
-copyenv(const char **oldenvp, struct rule *rule)
+int
+mygetpwuid_r(uid_t uid, struct passwd *pwd, struct passwd **result)
{
- const char *safeset[] = {
- "DISPLAY", "HOME", "LOGNAME", "MAIL", "SHELL",
- "PATH", "TERM", "USER", "USERNAME",
- NULL,
- };
- int nsafe;
- int nextras = 0;
- char **envp;
- const char **extra;
- int ei;
- int i, j;
-
- if ((rule->options & KEEPENV) && !rule->envlist) {
- j = arraylen(oldenvp);
- envp = reallocarray(NULL, j + 1, sizeof(char *));
- if (!envp)
- err(1, "reallocarray");
- for (i = 0; i < j; i++) {
- if (!(envp[i] = strdup(oldenvp[i])))
- err(1, "strdup");
- }
- envp[i] = NULL;
- return envp;
- }
-
- nsafe = arraylen(safeset);
- if ((extra = rule->envlist)) {
- nextras = arraylen(extra);
- for (i = 0; i < nsafe; i++) {
- for (j = 0; j < nextras; j++) {
- if (strcmp(extra[j], safeset[i]) == 0) {
- extra[j--] = extra[nextras--];
- extra[nextras] = NULL;
- }
- }
- }
+ int rv;
+ char *buf;
+ static long pwsz = 0;
+ size_t buflen;
+
+ *result = NULL;
+
+ if (pwsz == 0)
+ pwsz = sysconf(_SC_GETPW_R_SIZE_MAX);
+
+ buflen = pwsz > 0 ? pwsz : 1024;
+
+ buf = malloc(buflen);
+ if (buf == NULL)
+ return errno;
+
+ while ((rv = getpwuid_r(uid, pwd, buf, buflen, result)) == ERANGE) {
+ size_t newsz;
+ newsz = buflen * 2;
+ if (newsz < buflen)
+ return rv;
+ buflen = newsz;
+ buf = realloc(buf, buflen);
+ if (buf == NULL)
+ return errno;
}
- envp = reallocarray(NULL, nsafe + nextras + 1, sizeof(char *));
- if (!envp)
- err(1, "can't allocate new environment");
-
- ei = 0;
- ei = copyenvhelper(oldenvp, safeset, nsafe, envp, ei);
- ei = copyenvhelper(oldenvp, rule->envlist, nextras, envp, ei);
- envp[ei] = NULL;
-
- return envp;
+ return rv;
}
-static void __dead
-fail(void)
+void
+authfail(int opt)
{
- fprintf(stderr, "Permission denied\n");
- exit(1);
+
+#ifdef DOAS_INSULTS
+ if (opt)
+ printf("%s\n", getinsult());
+#endif
+
+ errx(1, "Authentication failed");
}
int
-main(int argc, char **argv, char **envp)
+main(int argc, char **argv)
{
- char cmdline[LINE_MAX];
- char myname[_PW_NAME_LEN + 1];
- uid_t uid, target = 0;
- gid_t groups[NGROUPS_MAX + 1];
- int ngroups;
- struct passwd *pw;
- struct rule *rule;
- const char *cmd;
- int i, ch;
const char *safepath = "/bin:/sbin:/usr/bin:/usr/sbin:"
"/usr/local/bin:/usr/local/sbin";
- int sflag = 0;
+ const char *confpath = NULL;
char *shargv[] = { NULL, NULL };
char *sh;
+ const char *p;
+ const char *cmd;
+ char cmdline[LINE_MAX];
+ struct passwd mypwstore, targpwstore;
+ struct passwd *mypw, *targpw;
+ const struct rule *rule;
+ uid_t uid;
+ uid_t target = 0;
+ gid_t groups[NGROUPS_MAX + 1];
+ int ngroups;
+ int i, ch, rv;
+ int sflag = 0;
+ int nflag = 0;
+ char cwdpath[PATH_MAX];
+ const char *cwd;
+ char **envp;
- parseconfig("/etc/doas.conf");
+ if (argc <= 0 || argv == NULL || argv[0] == NULL) {
+ fprintf(stderr, "doas: executed without argv\n");
+ exit(1);
+ }
+
+ setprogname("doas");
+
+ closefrom(STDERR_FILENO + 1);
+
+ uid = getuid();
- while ((ch = getopt(argc, argv, "su:")) != -1) {
+ while ((ch = getopt(argc, argv, "+C:Lnsu:")) != -1) {
switch (ch) {
+ case 'C':
+ confpath = optarg;
+ break;
+ case 'L':
+#if defined(USE_TIMESTAMP)
+ exit(timestamp_clear() == -1);
+#else
+ exit(0);
+#endif
case 'u':
if (parseuid(optarg, &target) != 0)
errx(1, "unknown user");
break;
+ case 'n':
+ nflag = 1;
+ break;
case 's':
sflag = 1;
break;
argv += optind;
argc -= optind;
- if ((!sflag && !argc) || (sflag && argc))
+ if (confpath) {
+ if (sflag)
+ usage();
+ } else if ((!sflag && !argc) || (sflag && argc))
usage();
- uid = getuid();
- pw = getpwuid(uid);
- if (!pw)
- err(1, "getpwuid failed");
- if (strlcpy(myname, pw->pw_name, sizeof(myname)) >= sizeof(myname))
- errx(1, "pw_name too long");
+ rv = mygetpwuid_r(uid, &mypwstore, &mypw);
+ if (rv != 0)
+ err(1, "getpwuid_r failed");
+ if (mypw == NULL)
+ errx(1, "no passwd entry for self");
ngroups = getgroups(NGROUPS_MAX, groups);
if (ngroups == -1)
err(1, "can't get groups");
if (sflag) {
sh = getenv("SHELL");
- if (sh == NULL || *sh == '\0')
- shargv[0] = pw->pw_shell;
- else
+ if (sh == NULL || *sh == '\0') {
+ shargv[0] = mypw->pw_shell;
+ } else
shargv[0] = sh;
argv = shargv;
argc = 1;
}
- cmd = argv[0];
- if (strlcpy(cmdline, argv[0], sizeof(cmdline)) >= sizeof(cmdline))
- errx(1, "command line too long");
+ if (confpath) {
+ checkconfig(confpath, argc, argv, uid, groups, ngroups,
+ target);
+ exit(1); /* fail safe */
+ }
+
+ if (geteuid())
+ errx(1, "not installed setuid");
+
+ parseconfig(DOAS_CONF, 1);
+
+ /* cmdline is used only for logging, no need to abort on truncate */
+ (void)strlcpy(cmdline, argv[0], sizeof(cmdline));
for (i = 1; i < argc; i++) {
if (strlcat(cmdline, " ", sizeof(cmdline)) >= sizeof(cmdline))
- errx(1, "command line too long");
+ break;
if (strlcat(cmdline, argv[i], sizeof(cmdline)) >= sizeof(cmdline))
- errx(1, "command line too long");
+ break;
}
- if (!permit(uid, groups, ngroups, &rule, target, cmd)) {
+ cmd = argv[0];
+ if (!permit(uid, groups, ngroups, &rule, target, cmd,
+ (const char **)argv + 1)) {
syslog(LOG_AUTHPRIV | LOG_NOTICE,
- "failed command for %s: %s", myname, cmdline);
- fail();
+ "command not permitted for %s: %s", mypw->pw_name, cmdline);
+ errc(1, EPERM, NULL);
}
if (!(rule->options & NOPASS)) {
- if (!auth_userokay(myname, NULL, NULL, NULL)) {
- syslog(LOG_AUTHPRIV | LOG_NOTICE,
- "failed password for %s", myname);
- fail();
- }
+ if (nflag)
+ errx(1, "Authentication required");
+
+ int ret = shadowauth(mypw->pw_name, rule->options & PERSIST);
+ if (ret == 5)
+ authfail(rule->options & INSULT);
}
- envp = copyenv((const char **)envp, rule);
- pw = getpwuid(target);
- if (!pw)
+ if ((p = getenv("PATH")) != NULL)
+ formerpath = strdup(p);
+ if (formerpath == NULL)
+ formerpath = "";
+
+ if (rule->cmd) {
+ if (setenv("PATH", safepath, 1) == -1)
+ err(1, "failed to set PATH '%s'", safepath);
+ }
+
+ rv = mygetpwuid_r(target, &targpwstore, &targpw);
+ if (rv != 0)
+ err(1, "getpwuid_r failed");
+ if (targpw == NULL)
errx(1, "no passwd entry for target");
- if (setusercontext(NULL, pw, target, LOGIN_SETGROUP |
+
+#ifdef HAVE_LOGIN_CAP_H
+ if (setusercontext(NULL, targpw, target, LOGIN_SETGROUP |
+ LOGIN_SETPATH |
LOGIN_SETPRIORITY | LOGIN_SETRESOURCES | LOGIN_SETUMASK |
LOGIN_SETUSER) != 0)
errx(1, "failed to set user context for target");
-
- syslog(LOG_AUTHPRIV | LOG_INFO, "%s ran command as %s: %s",
- myname, pw->pw_name, cmdline);
+#else
+ if (setresgid(targpw->pw_gid, targpw->pw_gid, targpw->pw_gid) != 0)
+ err(1, "setresgid");
+ if (initgroups(targpw->pw_name, targpw->pw_gid) != 0)
+ err(1, "initgroups");
+ if (setresuid(target, target, target) != 0)
+ err(1, "setresuid");
if (setenv("PATH", safepath, 1) == -1)
err(1, "failed to set PATH '%s'", safepath);
+#endif
+
+ if (getcwd(cwdpath, sizeof(cwdpath)) == NULL)
+ cwd = "(failed)";
+ else
+ cwd = cwdpath;
+
+ if (!(rule->options & NOLOG)) {
+ syslog(LOG_AUTHPRIV | LOG_INFO,
+ "%s ran command %s as %s from %s",
+ mypw->pw_name, cmdline, targpw->pw_name, cwd);
+ }
+
+ envp = prepenv(rule, mypw, targpw);
+
+ /* setusercontext set path for the next process, so reset it for us */
+ if (rule->cmd) {
+ if (setenv("PATH", safepath, 1) == -1)
+ err(1, "failed to set PATH '%s'", safepath);
+ } else {
+ if (setenv("PATH", formerpath, 1) == -1)
+ err(1, "failed to set PATH '%s'", formerpath);
+ }
execvpe(cmd, argv, envp);
+ if (errno == ENOENT)
+ errx(1, "%s: command not found", cmd);
err(1, "%s", cmd);
}
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