-/* $OpenBSD: doas.c,v 1.1 2015/07/16 20:44:21 tedu Exp $ */
+/* $OpenBSD: doas.c,v 1.52 2016/04/28 04:48:56 tedu Exp $ */
/*
* Copyright (c) 2015 Ted Unangst <tedu@openbsd.org>
*
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
+
#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
#include <limits.h>
-#include <login_cap.h>
-#include <bsd_auth.h>
+#if __OpenBSD__
+# include <login_cap.h>
+# include <readpassphrase.h>
+#endif
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <pwd.h>
#include <grp.h>
#include <syslog.h>
+#include <errno.h>
+
+#include "includes.h"
#include "doas.h"
static void __dead
usage(void)
{
- fprintf(stderr, "usage: doas [-u user] command [args]\n");
+ fprintf(stderr, "usage: doas [-Lns] "
+#ifdef __OpenBSD__
+ "[-a style] "
+#endif
+ "[-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)
{
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;
+ return 0;
+ }
+ *gid = strtonum(s, 0, GID_MAX, &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;
*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);
}
+
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)
+#ifdef USE_BSD_AUTH
+static void
+authuser(char *myname, char *login_style, int persist)
{
- 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 *));
- for (i = 0; i < j; i++) {
- if (!(envp[i] = strdup(oldenvp[i])))
- err(1, "strdup");
- }
- envp[i] = NULL;
- return envp;
+ char *challenge = NULL, *response, rbuf[1024], cbuf[128];
+ auth_session_t *as;
+ int fd = -1;
+
+ if (persist)
+ fd = open("/dev/tty", O_RDWR);
+ if (fd != -1) {
+ if (ioctl(fd, TIOCCHKVERAUTH) == 0)
+ goto good;
}
- 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;
- }
- }
- }
+ if (!(as = auth_userchallenge(myname, login_style, "auth-doas",
+ &challenge)))
+ errx(1, "Authorization failed");
+ if (!challenge) {
+ char host[HOST_NAME_MAX + 1];
+ if (gethostname(host, sizeof(host)))
+ snprintf(host, sizeof(host), "?");
+ snprintf(cbuf, sizeof(cbuf),
+ "\rdoas (%.32s@%.32s) password: ", myname, host);
+ challenge = cbuf;
+ }
+ response = readpassphrase(challenge, rbuf, sizeof(rbuf),
+ RPP_REQUIRE_TTY);
+ if (response == NULL && errno == ENOTTY) {
+ syslog(LOG_AUTHPRIV | LOG_NOTICE,
+ "tty required for %s", myname);
+ errx(1, "a tty is required");
+ }
+ if (!auth_userresponse(as, response, 0)) {
+ explicit_bzero(rbuf, sizeof(rbuf));
+ syslog(LOG_AUTHPRIV | LOG_NOTICE,
+ "failed auth for %s", myname);
+ errx(1, "Authorization failed");
+ }
+ explicit_bzero(rbuf, sizeof(rbuf));
+good:
+ if (fd != -1) {
+ int secs = 5 * 60;
+ ioctl(fd, TIOCSETVERAUTH, &secs);
+ close(fd);
}
-
- 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;
-}
-
-static void __dead
-fail(void)
-{
- const char *msgs[] = {
- "No lollygagging!",
- "Better luck next time.",
- "PEBKAC detected.",
- "That's what happens when you're lazy.",
- "It is clear that this has not been thought through.",
- "That's the most ridiculous thing I've heard in the last two or three minutes!",
- "No sane people allowed here. Go home.",
- "I would explain, but I am too drunk.",
- "You're not allowed to have an opinion.",
- "Complaint forms are handled in another department.",
- };
- const char *m;
-
- m = msgs[arc4random_uniform(sizeof(msgs) / sizeof(msgs[0]))];
- fprintf(stderr, "%s\n", m);
- exit(1);
}
+#endif
int
-main(int argc, char **argv, char **envp)
+main(int argc, char **argv)
{
- char cmdline[1024];
- char myname[32];
- uid_t uid, target = 0;
+ const char *safepath = "/bin:/sbin:/usr/bin:/usr/sbin:"
+ "/usr/local/bin:/usr/local/sbin";
+ const char *confpath = NULL;
+ char *shargv[] = { NULL, NULL };
+ char *sh;
+ const char *cmd;
+ char cmdline[LINE_MAX];
+#ifdef __OpenBSD__
+ char mypwbuf[_PW_BUF_LEN], targpwbuf[_PW_BUF_LEN];
+#else
+ char *mypwbuf = NULL, *targpwbuf = NULL;
+#endif
+ 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;
- 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 i, ch, rv;
+ int sflag = 0;
+ int nflag = 0;
+ char cwdpath[PATH_MAX];
+ const char *cwd;
+ char **envp;
+#ifdef USE_BSD_AUTH
+ char *login_style = NULL;
+#endif
+
+ setprogname("doas");
+
+ closefrom(STDERR_FILENO + 1);
+
+ uid = getuid();
- parseconfig("/etc/doas.conf");
+#ifdef USE_BSD_AUTH
+# define OPTSTRING "a:C:Lnsu:"
+#else
+# define OPTSTRING "+C:Lnsu:"
+#endif
- while ((ch = getopt(argc, argv, "u:")) != -1) {
+ while ((ch = getopt(argc, argv, OPTSTRING)) != -1) {
switch (ch) {
+#ifdef USE_BSD_AUTH
+ case 'a':
+ login_style = optarg;
+ break;
+#endif
+ case 'C':
+ confpath = optarg;
+ break;
+ case 'L':
+#if defined(USE_BSD_AUTH)
+ i = open("/dev/tty", O_RDWR);
+ if (i != -1)
+ ioctl(i, TIOCCLRVERAUTH);
+ exit(i == -1);
+#elif 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;
default:
usage();
break;
argv += optind;
argc -= optind;
- if (!argc)
+ if (confpath) {
+ if (sflag)
+ usage();
+ } else if ((!sflag && !argc) || (sflag && argc))
usage();
- cmd = argv[0];
- strlcpy(cmdline, argv[0], sizeof(cmdline));
- for (i = 1; i < argc; i++) {
- strlcat(cmdline, " ", sizeof(cmdline));
- strlcat(cmdline, argv[i], sizeof(cmdline));
+#ifdef __OpenBSD__
+ rv = getpwuid_r(uid, &mypwstore, mypwbuf, sizeof(mypwbuf), &mypw);
+ if (rv != 0)
+ err(1, "getpwuid_r failed");
+#else
+ for (size_t sz = 1024; sz <= 16*1024; sz *= 2) {
+ mypwbuf = reallocarray(mypwbuf, sz, sizeof (char));
+ if (mypwbuf == NULL)
+ errx(1, "can't allocate mypwbuf");
+ rv = getpwuid_r(uid, &mypwstore, mypwbuf, sz, &mypw);
+ if (rv != ERANGE)
+ break;
}
-
- uid = getuid();
- pw = getpwuid(uid);
- if (!pw)
- err(1, "getpwuid failed");
- strlcpy(myname, pw->pw_name, sizeof(myname));
+ if (rv != 0)
+ err(1, "getpwuid_r failed");
+#endif
+ if (mypw == NULL)
+ errx(1, "no passwd entry for self");
ngroups = getgroups(NGROUPS_MAX, groups);
if (ngroups == -1)
err(1, "can't get groups");
groups[ngroups++] = getgid();
- if (!permit(uid, groups, ngroups, &rule, target, cmd)) {
- syslog(LOG_AUTHPRIV | LOG_NOTICE, "failed command for %s: %s", myname, cmdline);
- fail();
+ if (sflag) {
+ sh = getenv("SHELL");
+ if (sh == NULL || *sh == '\0') {
+ shargv[0] = mypw->pw_shell;
+ } else
+ shargv[0] = sh;
+ argv = shargv;
+ argc = 1;
}
+ if (confpath) {
+ checkconfig(confpath, argc, argv, uid, groups, ngroups,
+ target);
+ exit(1); /* fail safe */
+ }
+
+ if (geteuid())
+ errx(1, "not installed setuid");
+
+ parseconfig("/etc/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))
+ break;
+ if (strlcat(cmdline, argv[i], sizeof(cmdline)) >= sizeof(cmdline))
+ break;
+ }
+
+ 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", mypw->pw_name, cmdline);
+ errc(1, EPERM, NULL);
+ }
+
+#if defined(__OpenBSD__) || defined(USE_SHADOW)
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, "Authorization required");
+
+# ifdef __OpenBSD__
+ authuser(mypw->pw_name, login_style, rule->options & PERSIST);
+# else
+ shadowauth(mypw->pw_name, rule->options & PERSIST);
+# endif
+ }
+
+# ifdef __OpenBSD__
+ if (pledge("stdio rpath getpw exec id", NULL) == -1)
+ err(1, "pledge");
+# endif
+
+#elif !defined(USE_PAM)
+ (void) nflag;
+ if (!(rule->options & NOPASS)) {
+ errx(1, "Authorization required");
}
- envp = copyenv((const char **)envp, rule);
+#endif /* !(__OpenBSD__ || USE_SHADOW) && !USE_PAM */
- pw = getpwuid(target);
- if (!pw)
+#ifdef __OpenBSD__
+ rv = getpwuid_r(target, &targpwstore, targpwbuf, sizeof(targpwbuf), &targpw);
+ if (rv != 0)
errx(1, "no passwd entry for target");
- if (setusercontext(NULL, pw, target, LOGIN_SETGROUP |
+#else
+ for (size_t sz = 1024; sz <= 16*1024; sz *= 2) {
+ targpwbuf = reallocarray(targpwbuf, sz, sizeof (char));
+ if (targpwbuf == NULL)
+ errx(1, "can't allocate targpwbuf");
+ rv = getpwuid_r(target, &targpwstore, targpwbuf, sz, &targpw);
+ if (rv != ERANGE)
+ break;
+ }
+ if (rv != 0)
+ err(1, "getpwuid_r failed");
+#endif
+ if (targpw == NULL)
+ err(1, "getpwuid_r failed");
+
+#if defined(USE_PAM)
+ pamauth(targpw->pw_name, mypw->pw_name, !nflag, rule->options & NOPASS,
+ rule->options & PERSIST);
+#endif
+
+#ifdef HAVE_SETUSERCONTEXT
+ if (setusercontext(NULL, targpw, target, LOGIN_SETGROUP |
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);
- setenv("PATH", safepath, 1);
+#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");
+#endif
+
+#ifdef __OpenBSD__
+ if (pledge("stdio rpath exec", NULL) == -1)
+ err(1, "pledge");
+#endif
+
+ if (getcwd(cwdpath, sizeof(cwdpath)) == NULL)
+ cwd = "(failed)";
+ else
+ cwd = cwdpath;
+
+#ifdef __OpenBSD__
+ if (pledge("stdio exec", NULL) == -1)
+ err(1, "pledge");
+#endif
+
+ syslog(LOG_AUTHPRIV | LOG_INFO, "%s ran command %s as %s from %s",
+ mypw->pw_name, cmdline, targpw->pw_name, cwd);
+
+ envp = prepenv(rule);
+
+ if (rule->cmd) {
+ if (setenv("PATH", safepath, 1) == -1)
+ err(1, "failed to set PATH '%s'", safepath);
+ }
execvpe(cmd, argv, envp);
+ if (errno == ENOENT)
+ errx(1, "%s: command not found", cmd);
err(1, "%s", cmd);
}
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