-/* $OpenBSD$ */
+/* $OpenBSD: doas.c,v 1.33 2015/07/30 17:04:33 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 <limits.h>
#include <login_cap.h>
#include <pwd.h>
#include <grp.h>
#include <syslog.h>
+#include <errno.h>
#include "doas.h"
static void __dead
usage(void)
{
- fprintf(stderr, "usage: doas [-u user] command [args]\n");
+ fprintf(stderr, "usage: doas [-ns] [-C config] [-u user] command [args]\n");
exit(1);
}
arraylen(const char **arr)
{
size_t cnt = 0;
+
while (*arr) {
cnt++;
arr++;
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)
+ 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");
+ if (checkperms)
+ fprintf(stderr, "doas is not enabled.\n");
+ else
+ warn("could not open config file");
exit(1);
}
+
+ 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);
}
+/*
+ * Copy the environment variables in safeset from oldenvp to envp.
+ */
static int
-copyenvhelper(const char **oldenvp, const char **safeset, int nsafe, char **envp, int ei)
+copyenvhelper(const char **oldenvp, const char **safeset, int nsafe,
+ char **envp, int ei)
{
int i;
+
for (i = 0; i < nsafe; i++) {
const char **oe = oldenvp;
while (*oe) {
copyenv(const char **oldenvp, struct rule *rule)
{
const char *safeset[] = {
- "DISPLAY", "HOME", "LOGNAME", "MAIL", "SHELL",
+ "DISPLAY", "HOME", "LOGNAME", "MAIL",
"PATH", "TERM", "USER", "USERNAME",
- NULL,
+ NULL
+ };
+ const char *badset[] = {
+ "ENV",
+ NULL
};
- int nsafe;
- int nextras = 0;
char **envp;
const char **extra;
int ei;
- int i, j;
-
+ int nsafe, nbad;
+ int nextras = 0;
+
+ /* if there was no envvar whitelist, pass all except badset ones */
+ nbad = arraylen(badset);
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");
+ size_t iold, inew;
+ size_t oldlen = arraylen(oldenvp);
+ envp = reallocarray(NULL, oldlen + 1, sizeof(char *));
+ if (!envp)
+ err(1, "reallocarray");
+ for (inew = iold = 0; iold < oldlen; iold++) {
+ size_t ibad;
+ for (ibad = 0; ibad < nbad; ibad++) {
+ size_t len = strlen(badset[ibad]);
+ if (strncmp(oldenvp[iold], badset[ibad], len) == 0 &&
+ oldenvp[iold][len] == '=') {
+ break;
+ }
+ }
+ if (ibad == nbad) {
+ if (!(envp[inew] = strdup(oldenvp[iold])))
+ err(1, "strdup");
+ inew++;
+ }
}
- envp[i] = NULL;
+ envp[inew] = NULL;
return envp;
}
nsafe = arraylen(safeset);
if ((extra = rule->envlist)) {
+ size_t isafe;
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--];
+ for (isafe = 0; isafe < nsafe; isafe++) {
+ size_t iextras;
+ for (iextras = 0; iextras < nextras; iextras++) {
+ if (strcmp(extra[iextras], safeset[isafe]) == 0) {
+ nextras--;
+ extra[iextras] = extra[nextras];
extra[nextras] = NULL;
+ iextras--;
}
}
}
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, m);
- fprintf(stderr, "\n");
+ fprintf(stderr, "Permission denied\n");
exit(1);
}
+static void __dead
+checkconfig(const char *confpath, int argc, char **argv,
+ uid_t uid, gid_t *groups, int ngroups, uid_t target)
+{
+ struct rule *rule;
+
+ setresuid(uid, uid, uid);
+ 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);
+ }
+}
+
int
main(int argc, char **argv, char **envp)
{
- char cmdline[1024];
- char myname[32];
- uid_t uid, target = 0;
- gid_t groups[NGROUPS_MAX + 1];
- int ngroups;
+ 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];
+ char myname[_PW_NAME_LEN + 1];
struct passwd *pw;
struct rule *rule;
- const char *cmd;
+ uid_t uid;
+ uid_t target = 0;
+ gid_t groups[NGROUPS_MAX + 1];
+ int ngroups;
int i, ch;
- const char *safepath = "/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin";
+ int sflag = 0;
+ int nflag = 0;
- parseconfig("/etc/doas.conf");
+ uid = getuid();
- while ((ch = getopt(argc, argv, "u:")) != -1) {
+ while ((ch = getopt(argc, argv, "C:nsu:")) != -1) {
switch (ch) {
+ case 'C':
+ confpath = optarg;
+ break;
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));
- }
-
- uid = getuid();
pw = getpwuid(uid);
if (!pw)
err(1, "getpwuid failed");
- strlcpy(myname, pw->pw_name, sizeof(myname));
+ if (strlcpy(myname, pw->pw_name, sizeof(myname)) >= sizeof(myname))
+ errx(1, "pw_name too long");
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);
+ if (sflag) {
+ sh = getenv("SHELL");
+ if (sh == NULL || *sh == '\0')
+ shargv[0] = pw->pw_shell;
+ else
+ shargv[0] = sh;
+ argv = shargv;
+ argc = 1;
+ }
+
+ if (confpath) {
+ checkconfig(confpath, argc, argv, uid, groups, ngroups,
+ target);
+ exit(1); /* fail safe */
+ }
+
+ 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", myname, cmdline);
fail();
}
if (!(rule->options & NOPASS)) {
+ if (nflag)
+ errx(1, "Authorization required");
if (!auth_userokay(myname, NULL, NULL, NULL)) {
- syslog(LOG_AUTHPRIV | LOG_NOTICE, "failed password for %s", myname);
+ syslog(LOG_AUTHPRIV | LOG_NOTICE,
+ "failed password for %s", myname);
fail();
}
}
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);
+ syslog(LOG_AUTHPRIV | LOG_INFO, "%s ran command as %s: %s",
+ myname, pw->pw_name, cmdline);
+ 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);
}
projects / opendoas.git / blobdiff