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6ee731caffec4b33df16f3999b424cfa0c8c9cd6
sudo/plugins/sudoers/sudoers.c
Todd C. Miller 6ee731caff Log when user-specified command line options are rejected by sudoers. 
We already audit those but in some cases they were not logged as well.
2020-09-23 08:02:43 -06:00

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/*
* SPDX-License-Identifier: ISC
*
* Copyright (c) 1993-1996, 1998-2020 Todd C. Miller <Todd.Miller@sudo.ws>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* Sponsored in part by the Defense Advanced Research Projects
* Agency (DARPA) and Air Force Research Laboratory, Air Force
* Materiel Command, USAF, under agreement number F39502-99-1-0512.
*/
/*
* This is an open source non-commercial project. Dear PVS-Studio, please check it.
* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
*/
#ifdef __TANDEM
# include <floss.h>
#endif
#include <config.h>
#include <sys/types.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <pwd.h>
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <netdb.h>
#ifdef HAVE_LOGIN_CAP_H
# include <login_cap.h>
# ifndef LOGIN_DEFROOTCLASS
# define LOGIN_DEFROOTCLASS "daemon"
# endif
# ifndef LOGIN_SETENV
# define LOGIN_SETENV 0
# endif
#endif
#ifdef HAVE_SELINUX
# include <selinux/selinux.h>
#endif
#include <ctype.h>
#ifndef HAVE_GETADDRINFO
# include "compat/getaddrinfo.h"
#endif
#include "sudoers.h"
#include "parse.h"
#include "auth/sudo_auth.h"
#include "sudo_iolog.h"
/*
* Prototypes
*/
static bool cb_fqdn(const union sudo_defs_val *);
static bool cb_runas_default(const union sudo_defs_val *);
static bool cb_tty_tickets(const union sudo_defs_val *);
static bool cb_umask(const union sudo_defs_val *);
static bool cb_runchroot(const union sudo_defs_val *);
static int set_cmnd(void);
static int create_admin_success_flag(void);
static bool init_vars(char * const *);
static bool set_loginclass(struct passwd *);
static bool set_runasgr(const char *, bool);
static bool set_runaspw(const char *, bool);
static bool tty_present(void);
/*
* Globals
*/
struct sudo_user sudo_user;
struct passwd *list_pw;
uid_t timestamp_uid;
gid_t timestamp_gid;
#ifdef HAVE_BSD_AUTH_H
char *login_style;
#endif /* HAVE_BSD_AUTH_H */
bool force_umask;
int sudo_mode;
static char *prev_user;
static char *runas_user;
static char *runas_group;
static struct sudo_nss_list *snl;
static bool unknown_runas_uid;
static bool unknown_runas_gid;
static int cmnd_status = -1;
#ifdef __linux__
static struct rlimit nproclimit;
#endif
/* XXX - must be extern for audit bits of sudo_auth.c */
int NewArgc;
char **NewArgv;
#ifdef SUDOERS_IOLOG_CLIENT
# define remote_iologs (!SLIST_EMPTY(&def_log_servers))
#else
# define remote_iologs 0
#endif
/*
* Unlimit the number of processes since Linux's setuid() will
* apply resource limits when changing uid and return EAGAIN if
* nproc would be exceeded by the uid switch.
*/
static void
unlimit_nproc(void)
{
#ifdef __linux__
struct rlimit rl;
debug_decl(unlimit_nproc, SUDOERS_DEBUG_UTIL);
if (getrlimit(RLIMIT_NPROC, &nproclimit) != 0)
sudo_warn("getrlimit(RLIMIT_NPROC)");
rl.rlim_cur = rl.rlim_max = RLIM_INFINITY;
if (setrlimit(RLIMIT_NPROC, &rl) != 0) {
rl.rlim_cur = rl.rlim_max = nproclimit.rlim_max;
if (setrlimit(RLIMIT_NPROC, &rl) != 0)
sudo_warn("setrlimit(RLIMIT_NPROC)");
}
debug_return;
#endif /* __linux__ */
}
/*
* Restore saved value of RLIMIT_NPROC.
*/
static void
restore_nproc(void)
{
#ifdef __linux__
debug_decl(restore_nproc, SUDOERS_DEBUG_UTIL);
if (setrlimit(RLIMIT_NPROC, &nproclimit) != 0)
sudo_warn("setrlimit(RLIMIT_NPROC)");
debug_return;
#endif /* __linux__ */
}
int
sudoers_init(void *info, char * const envp[])
{
struct sudo_nss *nss, *nss_next;
int oldlocale, sources = 0;
static int ret = -1;
debug_decl(sudoers_init, SUDOERS_DEBUG_PLUGIN);
if (ret == true)
debug_return_int(true);
bindtextdomain("sudoers", LOCALEDIR);
/* Register fatal/fatalx callback. */
sudo_fatal_callback_register(sudoers_cleanup);
/* Initialize environment functions (including replacements). */
if (!env_init(envp))
debug_return_int(-1);
/* Setup defaults data structures. */
if (!init_defaults()) {
sudo_warnx("%s", U_("unable to initialize sudoers default values"));
debug_return_int(-1);
}
/* Parse info from front-end. */
sudo_mode = sudoers_policy_deserialize_info(info, &runas_user, &runas_group);
if (ISSET(sudo_mode, MODE_ERROR))
debug_return_int(-1);
if (!init_vars(envp))
debug_return_int(-1);
/* Parse nsswitch.conf for sudoers order. */
snl = sudo_read_nss();
/* LDAP or NSS may modify the euid so we need to be root for the open. */
if (!set_perms(PERM_ROOT))
debug_return_int(-1);
/*
* Open and parse sudoers, set global defaults.
* Uses the C locale unless another is specified in sudoers.
*/
sudoers_setlocale(SUDOERS_LOCALE_SUDOERS, &oldlocale);
sudo_warn_set_locale_func(sudoers_warn_setlocale);
init_parser(sudoers_file, false, false);
TAILQ_FOREACH_SAFE(nss, snl, entries, nss_next) {
if (nss->open(nss) == -1 || (nss->parse_tree = nss->parse(nss)) == NULL) {
TAILQ_REMOVE(snl, nss, entries);
continue;
}
sources++;
if (nss->getdefs(nss) == -1 || !update_defaults(nss->parse_tree, NULL,
SETDEF_GENERIC|SETDEF_HOST|SETDEF_USER|SETDEF_RUNAS, false)) {
log_warningx(SLOG_SEND_MAIL|SLOG_NO_STDERR,
N_("problem with defaults entries"));
}
}
if (sources == 0) {
sudo_warnx("%s", U_("no valid sudoers sources found, quitting"));
goto cleanup;
}
/* Set login class if applicable (after sudoers is parsed). */
if (set_loginclass(runas_pw ? runas_pw : sudo_user.pw))
ret = true;
cleanup:
if (!restore_perms())
ret = -1;
/* Restore user's locale. */
sudo_warn_set_locale_func(NULL);
sudoers_setlocale(oldlocale, NULL);
debug_return_int(ret);
}
/*
* Expand I/O log dir and file into a full path.
* Returns the full I/O log path prefixed with "iolog_path=".
* Sets sudo_user.iolog_file as a side effect.
*/
static char *
format_iolog_path(void)
{
char dir[PATH_MAX], file[PATH_MAX];
char *iolog_path = NULL;
int oldlocale;
bool ok;
debug_decl(format_iolog_path, SUDOERS_DEBUG_PLUGIN);
/* Use sudoers locale for strftime() */
sudoers_setlocale(SUDOERS_LOCALE_SUDOERS, &oldlocale);
ok = expand_iolog_path(def_iolog_dir, dir, sizeof(dir),
&sudoers_iolog_path_escapes[1], NULL);
if (ok) {
ok = expand_iolog_path(def_iolog_file, file, sizeof(file),
&sudoers_iolog_path_escapes[0], dir);
}
sudoers_setlocale(oldlocale, NULL);
if (!ok)
goto done;
if (asprintf(&iolog_path, "iolog_path=%s/%s", dir, file) == -1) {
iolog_path = NULL;
goto done;
}
/* Stash pointer to the I/O log file for use when logging. */
sudo_user.iolog_file =
iolog_path + sizeof("iolog_path=") - 1 + strlen(dir) + 1;
done:
debug_return_str(iolog_path);
}
static int
check_user_runchroot(void)
{
debug_decl(check_user_runchroot, SUDOERS_DEBUG_PLUGIN);
if (user_runchroot == NULL)
debug_return_bool(true);
sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
"def_runchroot %s, user_runchroot %s",
def_runchroot ? def_runchroot : "none",
user_runchroot ? user_runchroot : "none");
if (def_runchroot == NULL || (strcmp(def_runchroot, "*") != 0 &&
strcmp(def_runchroot, user_runchroot) != 0)) {
audit_failure(NewArgv,
N_("user not allowed to change root directory to %s"),
user_runchroot);
log_warningx(SLOG_NO_STDERR,
N_("user not allowed to change root directory to %s"),
user_runchroot);
sudo_warnx(U_("you are not permitted to use the -R option with %s"),
user_cmnd);
debug_return_bool(false);
}
free(def_runchroot);
if ((def_runchroot = strdup(user_runchroot)) == NULL) {
sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
debug_return_bool(-1);
}
debug_return_bool(true);
}
static int
check_user_runcwd(void)
{
debug_decl(check_user_runcwd, SUDOERS_DEBUG_PLUGIN);
sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
"def_runcwd %s, user_runcwd %s, user_cwd %s",
def_runcwd ? def_runcwd : "none", user_runcwd ? user_runcwd : "none",
user_cwd ? user_cwd : "none");
if (strcmp(user_cwd, user_runcwd) != 0) {
if (def_runcwd == NULL || strcmp(def_runcwd, "*") != 0) {
audit_failure(NewArgv,
N_("user not allowed to change directory to %s"), user_runcwd);
log_warningx(SLOG_NO_STDERR,
N_("user not allowed to change directory to %s"), user_runcwd);
sudo_warnx(U_("you are not permitted to use the -D option with %s"),
user_cmnd);
debug_return_bool(false);
}
free(def_runcwd);
if ((def_runcwd = strdup(user_runcwd)) == NULL) {
sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
debug_return_int(-1);
}
}
debug_return_bool(true);
}
int
sudoers_policy_main(int argc, char * const argv[], int pwflag, char *env_add[],
bool verbose, void *closure)
{
char *iolog_path = NULL;
mode_t cmnd_umask = ACCESSPERMS;
struct sudo_nss *nss;
int oldlocale, validated, ret = -1;
debug_decl(sudoers_policy_main, SUDOERS_DEBUG_PLUGIN);
sudo_warn_set_locale_func(sudoers_warn_setlocale);
unlimit_nproc();
/* Is root even allowed to run sudo? */
if (user_uid == 0 && !def_root_sudo) {
/* Not an audit event (should it be?). */
sudo_warnx("%s",
U_("sudoers specifies that root is not allowed to sudo"));
goto bad;
}
if (!set_perms(PERM_INITIAL))
goto bad;
/* Environment variables specified on the command line. */
if (env_add != NULL && env_add[0] != NULL)
sudo_user.env_vars = env_add;
/*
* Make a local copy of argc/argv, with special handling
* for pseudo-commands and the '-i' option.
*/
if (argc == 0) {
NewArgc = 1;
NewArgv = reallocarray(NULL, NewArgc + 1, sizeof(char *));
if (NewArgv == NULL) {
sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
goto done;
}
sudoers_gc_add(GC_VECTOR, NewArgv);
NewArgv[0] = user_cmnd;
NewArgv[1] = NULL;
} else {
/* Must leave an extra slot before NewArgv for bash's --login */
NewArgc = argc;
NewArgv = reallocarray(NULL, NewArgc + 2, sizeof(char *));
if (NewArgv == NULL) {
sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
goto done;
}
sudoers_gc_add(GC_VECTOR, NewArgv);
NewArgv++; /* reserve an extra slot for --login */
memcpy(NewArgv, argv, argc * sizeof(char *));
NewArgv[NewArgc] = NULL;
if (ISSET(sudo_mode, MODE_LOGIN_SHELL) && runas_pw != NULL) {
NewArgv[0] = strdup(runas_pw->pw_shell);
if (NewArgv[0] == NULL) {
sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
goto done;
}
sudoers_gc_add(GC_PTR, NewArgv[0]);
}
}
/* If given the -P option, set the "preserve_groups" flag. */
if (ISSET(sudo_mode, MODE_PRESERVE_GROUPS))
def_preserve_groups = true;
/* Find command in path and apply per-command Defaults. */
cmnd_status = set_cmnd();
if (cmnd_status == NOT_FOUND_ERROR)
goto done;
/* Check for -C overriding def_closefrom. */
if (user_closefrom >= 0 && user_closefrom != def_closefrom) {
if (!def_closefrom_override) {
audit_failure(NewArgv,
N_("user not allowed to override closefrom limit"));
log_warningx(SLOG_NO_STDERR,
N_("user not allowed to override closefrom limit"));
sudo_warnx("%s", U_("you are not permitted to use the -C option"));
goto bad;
}
def_closefrom = user_closefrom;
}
/*
* Check sudoers sources, using the locale specified in sudoers.
*/
sudoers_setlocale(SUDOERS_LOCALE_SUDOERS, &oldlocale);
validated = sudoers_lookup(snl, sudo_user.pw, &cmnd_status, pwflag);
if (ISSET(validated, VALIDATE_ERROR)) {
/* The lookup function should have printed an error. */
goto done;
}
/* Restore user's locale. */
sudoers_setlocale(oldlocale, NULL);
if (safe_cmnd == NULL) {
if ((safe_cmnd = strdup(user_cmnd)) == NULL) {
sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
goto done;
}
}
/* Defer uid/gid checks until after defaults have been updated. */
if (unknown_runas_uid && !def_runas_allow_unknown_id) {
audit_failure(NewArgv, N_("unknown user: %s"), runas_pw->pw_name);
log_warningx(0, N_("unknown user: %s"), runas_pw->pw_name);
goto done;
}
if (runas_gr != NULL) {
if (unknown_runas_gid && !def_runas_allow_unknown_id) {
audit_failure(NewArgv, N_("unknown group: %s"), runas_gr->gr_name);
log_warningx(0, N_("unknown group: %s"), runas_gr->gr_name);
goto done;
}
}
/*
* Look up the timestamp dir owner if one is specified.
*/
if (def_timestampowner) {
struct passwd *pw = NULL;
if (*def_timestampowner == '#') {
const char *errstr;
uid_t uid = sudo_strtoid(def_timestampowner + 1, &errstr);
if (errstr == NULL)
pw = sudo_getpwuid(uid);
}
if (pw == NULL)
pw = sudo_getpwnam(def_timestampowner);
if (pw != NULL) {
timestamp_uid = pw->pw_uid;
timestamp_gid = pw->pw_gid;
sudo_pw_delref(pw);
} else {
/* XXX - audit too? */
log_warningx(SLOG_SEND_MAIL,
N_("timestamp owner (%s): No such user"), def_timestampowner);
timestamp_uid = ROOT_UID;
timestamp_gid = ROOT_GID;
}
}
/* If no command line args and "shell_noargs" is not set, error out. */
if (ISSET(sudo_mode, MODE_IMPLIED_SHELL) && !def_shell_noargs) {
/* Not an audit event. */
ret = -2; /* usage error */
goto done;
}
/* Bail if a tty is required and we don't have one. */
if (def_requiretty && !tty_present()) {
audit_failure(NewArgv, N_("no tty"));
log_warningx(SLOG_NO_STDERR, N_("no tty"));
sudo_warnx("%s", U_("sorry, you must have a tty to run sudo"));
goto bad;
}
/* Check runas user's shell. */
if (!check_user_shell(runas_pw)) {
audit_failure(NewArgv, N_("invalid shell for user %s: %s"),
runas_pw->pw_name, runas_pw->pw_shell);
log_warningx(SLOG_RAW_MSG, N_("invalid shell for user %s: %s"),
runas_pw->pw_name, runas_pw->pw_shell);
goto bad;
}
/*
* We don't reset the environment for sudoedit or if the user
* specified the -E command line flag and they have setenv privs.
*/
if (ISSET(sudo_mode, MODE_EDIT) ||
(ISSET(sudo_mode, MODE_PRESERVE_ENV) && def_setenv))
def_env_reset = false;
/* Build a new environment that avoids any nasty bits. */
if (!rebuild_env())
goto bad;
/* Require a password if sudoers says so. */
switch (check_user(validated, sudo_mode)) {
case true:
/* user authenticated successfully. */
break;
case false:
/* Note: log_denial() calls audit for us. */
if (!ISSET(validated, VALIDATE_SUCCESS)) {
/* Only display a denial message if no password was read. */
if (!log_denial(validated, def_passwd_tries <= 0))
goto done;
}
goto bad;
default:
/* some other error, ret is -1. */
goto done;
}
/* Check whether user_runchroot is permitted (if specified). */
switch (check_user_runchroot()) {
case true:
break;
case false:
goto bad;
default:
goto done;
}
/* Check whether user_runcwd is permitted (if specified). */
switch (check_user_runcwd()) {
case true:
break;
case false:
goto bad;
default:
goto done;
}
/* If run as root with SUDO_USER set, set sudo_user.pw to that user. */
/* XXX - causes confusion when root is not listed in sudoers */
if (sudo_mode & (MODE_RUN | MODE_EDIT) && prev_user != NULL) {
if (user_uid == 0 && strcmp(prev_user, "root") != 0) {
struct passwd *pw;
if ((pw = sudo_getpwnam(prev_user)) != NULL) {
if (sudo_user.pw != NULL)
sudo_pw_delref(sudo_user.pw);
sudo_user.pw = pw;
}
}
}
/* If the user was not allowed to run the command we are done. */
if (!ISSET(validated, VALIDATE_SUCCESS)) {
/* Note: log_failure() calls audit for us. */
if (!log_failure(validated, cmnd_status))
goto done;
goto bad;
}
/* Create Ubuntu-style dot file to indicate sudo was successful. */
if (create_admin_success_flag() == -1)
goto done;
/* Finally tell the user if the command did not exist. */
if (cmnd_status == NOT_FOUND_DOT) {
audit_failure(NewArgv, N_("command in current directory"));
sudo_warnx(U_("ignoring \"%s\" found in '.'\nUse \"sudo ./%s\" if this is the \"%s\" you wish to run."), user_cmnd, user_cmnd, user_cmnd);
goto bad;
} else if (cmnd_status == NOT_FOUND) {
if (ISSET(sudo_mode, MODE_CHECK)) {
audit_failure(NewArgv, N_("%s: command not found"),
NewArgv[0]);
sudo_warnx(U_("%s: command not found"), NewArgv[0]);
} else {
audit_failure(NewArgv, N_("%s: command not found"),
user_cmnd);
sudo_warnx(U_("%s: command not found"), user_cmnd);
}
goto bad;
}
/* If user specified a timeout make sure sudoers allows it. */
if (!def_user_command_timeouts && user_timeout > 0) {
audit_failure(NewArgv, N_("user not allowed to set a command timeout"));
log_warningx(SLOG_NO_STDERR,
N_("user not allowed to set a command timeout"));
sudo_warnx("%s",
U_("sorry, you are not allowed set a command timeout"));
goto bad;
}
/* If user specified env vars make sure sudoers allows it. */
if (ISSET(sudo_mode, MODE_RUN) && !def_setenv) {
if (ISSET(sudo_mode, MODE_PRESERVE_ENV)) {
audit_failure(NewArgv,
N_("user not allowed to preserve the environment"));
log_warningx(SLOG_NO_STDERR,
N_("user not allowed to preserve the environment"));
sudo_warnx("%s",
U_("sorry, you are not allowed to preserve the environment"));
goto bad;
} else {
if (!validate_env_vars(sudo_user.env_vars))
goto bad;
}
}
if (ISSET(sudo_mode, (MODE_RUN | MODE_EDIT)) && !remote_iologs) {
if ((def_log_input || def_log_output) && def_iolog_file && def_iolog_dir) {
if ((iolog_path = format_iolog_path()) == NULL) {
if (!def_ignore_iolog_errors)
goto done;
/* Unable to expand I/O log path, disable I/O logging. */
def_log_input = false;
def_log_output = false;
}
}
}
switch (sudo_mode & MODE_MASK) {
case MODE_CHECK:
ret = display_cmnd(snl, list_pw ? list_pw : sudo_user.pw);
break;
case MODE_LIST:
ret = display_privs(snl, list_pw ? list_pw : sudo_user.pw, verbose);
break;
case MODE_VALIDATE:
case MODE_RUN:
case MODE_EDIT:
/* ret may be overridden by "goto bad" later */
ret = true;
break;
default:
/* Should not happen. */
sudo_warnx("internal error, unexpected sudo mode 0x%x", sudo_mode);
goto done;
}
/* Cleanup sudoers sources */
TAILQ_FOREACH(nss, snl, entries) {
nss->close(nss);
}
if (def_group_plugin)
group_plugin_unload();
init_parser(NULL, false, false);
if (ISSET(sudo_mode, (MODE_VALIDATE|MODE_CHECK|MODE_LIST))) {
/* ret already set appropriately */
goto done;
}
/*
* Set umask based on sudoers.
* If user's umask is more restrictive, OR in those bits too
* unless umask_override is set.
*/
if (def_umask != ACCESSPERMS) {
cmnd_umask = def_umask;
if (!def_umask_override)
cmnd_umask |= user_umask;
}
if (ISSET(sudo_mode, MODE_LOGIN_SHELL)) {
char *p;
/* Convert /bin/sh -> -sh so shell knows it is a login shell */
if ((p = strrchr(NewArgv[0], '/')) == NULL)
p = NewArgv[0];
*p = '-';
NewArgv[0] = p;
/*
* Newer versions of bash require the --login option to be used
* in conjunction with the -c option even if the shell name starts
* with a '-'. Unfortunately, bash 1.x uses -login, not --login
* so this will cause an error for that.
*/
if (NewArgc > 1 && strcmp(NewArgv[0], "-bash") == 0 &&
strcmp(NewArgv[1], "-c") == 0) {
/* Use the extra slot before NewArgv so we can store --login. */
NewArgv--;
NewArgc++;
NewArgv[0] = NewArgv[1];
NewArgv[1] = "--login";
}
#if defined(_AIX) || (defined(__linux__) && !defined(HAVE_PAM))
/* Insert system-wide environment variables. */
if (!read_env_file(_PATH_ENVIRONMENT, true, false))
sudo_warn("%s", _PATH_ENVIRONMENT);
#endif
#ifdef HAVE_LOGIN_CAP_H
/* Set environment based on login class. */
if (login_class) {
login_cap_t *lc = login_getclass(login_class);
if (lc != NULL) {
setusercontext(lc, runas_pw, runas_pw->pw_uid, LOGIN_SETPATH|LOGIN_SETENV);
login_close(lc);
}
}
#endif /* HAVE_LOGIN_CAP_H */
}
/* Insert system-wide environment variables. */
if (def_restricted_env_file) {
if (!read_env_file(def_restricted_env_file, false, true))
sudo_warn("%s", def_restricted_env_file);
}
if (def_env_file) {
if (!read_env_file(def_env_file, false, false))
sudo_warn("%s", def_env_file);
}
/* Insert user-specified environment variables. */
if (!insert_env_vars(sudo_user.env_vars))
goto done;
/* Note: must call audit before uid change. */
if (ISSET(sudo_mode, MODE_EDIT)) {
char **edit_argv;
int edit_argc;
const char *env_editor;
free(safe_cmnd);
safe_cmnd = find_editor(NewArgc - 1, NewArgv + 1, &edit_argc,
&edit_argv, NULL, &env_editor, false);
if (safe_cmnd == NULL) {
if (errno != ENOENT)
goto done;
audit_failure(NewArgv, N_("%s: command not found"),
env_editor ? env_editor : def_editor);
sudo_warnx(U_("%s: command not found"),
env_editor ? env_editor : def_editor);
goto bad;
}
sudoers_gc_add(GC_VECTOR, edit_argv);
NewArgv = edit_argv;
NewArgc = edit_argc;
/* We want to run the editor with the unmodified environment. */
env_swap_old();
}
goto done;
bad:
ret = false;
done:
/* Setup execution environment to pass back to front-end. */
if (ret != -1) {
if (!sudoers_policy_exec_setup(NewArgv, env_get(), cmnd_umask,
iolog_path, closure))
ret = -1;
}
/* Zero out stashed copy of environment, it is owned by the front-end. */
(void)env_init(NULL);
if (!rewind_perms())
ret = -1;
restore_nproc();
/* Destroy the password and group caches and free the contents. */
sudo_freepwcache();
sudo_freegrcache();
sudo_warn_set_locale_func(NULL);
debug_return_int(ret);
}
/*
* Initialize timezone and fill in sudo_user struct.
*/
static bool
init_vars(char * const envp[])
{
char * const * ep;
bool unknown_user = false;
debug_decl(init_vars, SUDOERS_DEBUG_PLUGIN);
if (!sudoers_initlocale(setlocale(LC_ALL, NULL), def_sudoers_locale)) {
sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
debug_return_bool(false);
}
#define MATCHES(s, v) \
(strncmp((s), (v), sizeof(v) - 1) == 0 && (s)[sizeof(v) - 1] != '\0')
for (ep = envp; *ep; ep++) {
switch (**ep) {
case 'K':
if (MATCHES(*ep, "KRB5CCNAME="))
user_ccname = *ep + sizeof("KRB5CCNAME=") - 1;
break;
case 'P':
if (MATCHES(*ep, "PATH="))
user_path = *ep + sizeof("PATH=") - 1;
break;
case 'S':
if (MATCHES(*ep, "SUDO_PROMPT=")) {
/* Don't override "sudo -p prompt" */
if (user_prompt == NULL)
user_prompt = *ep + sizeof("SUDO_PROMPT=") - 1;
break;
}
if (MATCHES(*ep, "SUDO_USER="))
prev_user = *ep + sizeof("SUDO_USER=") - 1;
break;
}
}
#undef MATCHES
/*
* Get a local copy of the user's passwd struct and group list if we
* don't already have them.
*/
if (sudo_user.pw == NULL) {
if ((sudo_user.pw = sudo_getpwnam(user_name)) == NULL) {
/*
* It is not unusual for users to place "sudo -k" in a .logout
* file which can cause sudo to be run during reboot after the
* YP/NIS/NIS+/LDAP/etc daemon has died.
*/
if (sudo_mode == MODE_KILL || sudo_mode == MODE_INVALIDATE) {
sudo_warnx(U_("unknown uid: %u"), (unsigned int) user_uid);
debug_return_bool(false);
}
/* Need to make a fake struct passwd for the call to log_warningx(). */
sudo_user.pw = sudo_mkpwent(user_name, user_uid, user_gid, NULL, NULL);
unknown_user = true;
}
}
if (user_gid_list == NULL)
user_gid_list = sudo_get_gidlist(sudo_user.pw, ENTRY_TYPE_ANY);
/* Store initialize permissions so we can restore them later. */
if (!set_perms(PERM_INITIAL))
debug_return_bool(false);
/* Set fqdn callback. */
sudo_defs_table[I_FQDN].callback = cb_fqdn;
/* Set group_plugin callback. */
sudo_defs_table[I_GROUP_PLUGIN].callback = cb_group_plugin;
/* Set runas callback. */
sudo_defs_table[I_RUNAS_DEFAULT].callback = cb_runas_default;
/* Set locale callback. */
sudo_defs_table[I_SUDOERS_LOCALE].callback = sudoers_locale_callback;
/* Set maxseq callback. */
sudo_defs_table[I_MAXSEQ].callback = cb_maxseq;
/* Set iolog_user callback. */
sudo_defs_table[I_IOLOG_USER].callback = cb_iolog_user;
/* Set iolog_group callback. */
sudo_defs_table[I_IOLOG_GROUP].callback = cb_iolog_group;
/* Set iolog_mode callback. */
sudo_defs_table[I_IOLOG_MODE].callback = cb_iolog_mode;
/* Set tty_tickets callback. */
sudo_defs_table[I_TTY_TICKETS].callback = cb_tty_tickets;
/* Set umask callback. */
sudo_defs_table[I_UMASK].callback = cb_umask;
/* Set runchroot callback. */
sudo_defs_table[I_RUNCHROOT].callback = cb_runchroot;
/* It is now safe to use log_warningx() and set_perms() */
if (unknown_user) {
log_warningx(SLOG_SEND_MAIL, N_("unknown uid: %u"),
(unsigned int) user_uid);
debug_return_bool(false);
}
/*
* Set runas passwd/group entries based on command line or sudoers.
* Note that if runas_group was specified without runas_user we
* run the command as the invoking user.
*/
if (runas_group != NULL) {
if (!set_runasgr(runas_group, false))
debug_return_bool(false);
if (!set_runaspw(runas_user ? runas_user : user_name, false))
debug_return_bool(false);
} else {
if (!set_runaspw(runas_user ? runas_user : def_runas_default, false))
debug_return_bool(false);
}
debug_return_bool(true);
}
/*
* Fill in user_cmnd and user_stat variables.
* Does not fill in user_base.
*/
int
set_cmnd_path(const char *runchroot)
{
char *path = user_path;
int ret;
debug_decl(set_cmnd_path, SUDOERS_DEBUG_PLUGIN);
if (def_secure_path && !user_is_exempt())
path = def_secure_path;
if (!set_perms(PERM_RUNAS))
debug_return_int(NOT_FOUND_ERROR);
ret = find_path(NewArgv[0], &user_cmnd, user_stat, path,
runchroot, def_ignore_dot, NULL);
if (!restore_perms())
debug_return_int(NOT_FOUND_ERROR);
if (ret == NOT_FOUND) {
/* Failed as root, try as invoking user. */
if (!set_perms(PERM_USER))
debug_return_int(false);
ret = find_path(NewArgv[0], &user_cmnd, user_stat, path,
runchroot, def_ignore_dot, NULL);
if (!restore_perms())
debug_return_int(NOT_FOUND_ERROR);
}
debug_return_int(ret);
}
/*
* Fill in user_cmnd, user_args, user_base and user_stat variables
* and apply any command-specific defaults entries.
*/
static int
set_cmnd(void)
{
struct sudo_nss *nss;
int ret = FOUND;
debug_decl(set_cmnd, SUDOERS_DEBUG_PLUGIN);
/* Allocate user_stat for find_path() and match functions. */
user_stat = calloc(1, sizeof(struct stat));
if (user_stat == NULL) {
sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
debug_return_int(NOT_FOUND_ERROR);
}
/* Default value for cmnd, overridden below. */
if (user_cmnd == NULL)
user_cmnd = NewArgv[0];
if (sudo_mode & (MODE_RUN | MODE_EDIT | MODE_CHECK)) {
if (ISSET(sudo_mode, MODE_RUN | MODE_CHECK)) {
const char *runchroot = user_runchroot;
if (runchroot == NULL && def_runchroot != NULL &&
strcmp(def_runchroot, "*") != 0)
runchroot = def_runchroot;
ret = set_cmnd_path(runchroot);
if (ret == NOT_FOUND_ERROR) {
if (errno == ENAMETOOLONG) {
audit_failure(NewArgv, N_("command too long"));
}
log_warning(0, "%s", NewArgv[0]);
debug_return_int(ret);
}
}
/* set user_args */
if (NewArgc > 1) {
char *to, *from, **av;
size_t size, n;
/* Alloc and build up user_args. */
for (size = 0, av = NewArgv + 1; *av; av++)
size += strlen(*av) + 1;
if (size == 0 || (user_args = malloc(size)) == NULL) {
sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
debug_return_int(NOT_FOUND_ERROR);
}
if (ISSET(sudo_mode, MODE_SHELL|MODE_LOGIN_SHELL)) {
/*
* When running a command via a shell, the sudo front-end
* escapes potential meta chars. We unescape non-spaces
* for sudoers matching and logging purposes.
*/
for (to = user_args, av = NewArgv + 1; (from = *av); av++) {
while (*from) {
if (from[0] == '\\' && !isspace((unsigned char)from[1]))
from++;
*to++ = *from++;
}
*to++ = ' ';
}
*--to = '\0';
} else {
for (to = user_args, av = NewArgv + 1; *av; av++) {
n = strlcpy(to, *av, size - (to - user_args));
if (n >= size - (to - user_args)) {
sudo_warnx(U_("internal error, %s overflow"), __func__);
debug_return_int(NOT_FOUND_ERROR);
}
to += n;
*to++ = ' ';
}
*--to = '\0';
}
}
}
if ((user_base = strrchr(user_cmnd, '/')) != NULL)
user_base++;
else
user_base = user_cmnd;
/* Convert "sudo sudoedit" -> "sudoedit" */
if (ISSET(sudo_mode, MODE_RUN) && strcmp(user_base, "sudoedit") == 0) {
CLR(sudo_mode, MODE_RUN);
SET(sudo_mode, MODE_EDIT);
sudo_warnx("%s", U_("sudoedit doesn't need to be run via sudo"));
user_base = user_cmnd = "sudoedit";
}
TAILQ_FOREACH(nss, snl, entries) {
if (!update_defaults(nss->parse_tree, NULL, SETDEF_CMND, false)) {
log_warningx(SLOG_SEND_MAIL|SLOG_NO_STDERR,
N_("problem with defaults entries"));
}
}
debug_return_int(ret);
}
/*
* Open sudoers and sanity check mode/owner/type.
* Returns a handle to the sudoers file or NULL on error.
*/
FILE *
open_sudoers(const char *sudoers, bool doedit, bool *keepopen)
{
struct stat sb;
FILE *fp = NULL;
bool perm_root = false;
debug_decl(open_sudoers, SUDOERS_DEBUG_PLUGIN);
if (!set_perms(PERM_SUDOERS))
debug_return_ptr(NULL);
again:
switch (sudo_secure_file(sudoers, sudoers_uid, sudoers_gid, &sb)) {
case SUDO_PATH_SECURE:
/*
* If we are expecting sudoers to be group readable by
* SUDOERS_GID but it is not, we must open the file as root,
* not uid 1.
*/
if (sudoers_uid == ROOT_UID && ISSET(sudoers_mode, S_IRGRP)) {
if (!ISSET(sb.st_mode, S_IRGRP) || sb.st_gid != SUDOERS_GID) {
if (!perm_root) {
if (!restore_perms() || !set_perms(PERM_ROOT))
debug_return_ptr(NULL);
}
}
}
/*
* Open sudoers and make sure we can read it so we can present
* the user with a reasonable error message (unlike the lexer).
*/
if ((fp = fopen(sudoers, "r")) == NULL) {
log_warning(SLOG_SEND_MAIL, N_("unable to open %s"), sudoers);
} else {
if (sb.st_size != 0 && fgetc(fp) == EOF) {
log_warning(SLOG_SEND_MAIL,
N_("unable to read %s"), sudoers);
fclose(fp);
fp = NULL;
} else {
/* Rewind fp and set close on exec flag. */
rewind(fp);
(void) fcntl(fileno(fp), F_SETFD, 1);
}
}
break;
case SUDO_PATH_MISSING:
/*
* If we tried to stat() sudoers as non-root but got EACCES,
* try again as root.
*/
if (errno == EACCES && geteuid() != ROOT_UID) {
int serrno = errno;
if (restore_perms()) {
if (!set_perms(PERM_ROOT))
debug_return_ptr(NULL);
perm_root = true;
goto again;
}
errno = serrno;
}
log_warning(SLOG_SEND_MAIL, N_("unable to stat %s"), sudoers);
break;
case SUDO_PATH_BAD_TYPE:
log_warningx(SLOG_SEND_MAIL,
N_("%s is not a regular file"), sudoers);
break;
case SUDO_PATH_WRONG_OWNER:
log_warningx(SLOG_SEND_MAIL,
N_("%s is owned by uid %u, should be %u"), sudoers,
(unsigned int) sb.st_uid, (unsigned int) sudoers_uid);
break;
case SUDO_PATH_WORLD_WRITABLE:
log_warningx(SLOG_SEND_MAIL, N_("%s is world writable"), sudoers);
break;
case SUDO_PATH_GROUP_WRITABLE:
log_warningx(SLOG_SEND_MAIL,
N_("%s is owned by gid %u, should be %u"), sudoers,
(unsigned int) sb.st_gid, (unsigned int) sudoers_gid);
break;
default:
/* NOTREACHED */
break;
}
if (!restore_perms()) {
/* unable to change back to root */
if (fp != NULL) {
fclose(fp);
fp = NULL;
}
}
debug_return_ptr(fp);
}
#ifdef HAVE_LOGIN_CAP_H
static bool
set_loginclass(struct passwd *pw)
{
const int errflags = SLOG_RAW_MSG;
login_cap_t *lc;
bool ret = true;
debug_decl(set_loginclass, SUDOERS_DEBUG_PLUGIN);
if (!def_use_loginclass)
goto done;
if (login_class && strcmp(login_class, "-") != 0) {
if (user_uid != 0 && pw->pw_uid != 0) {
sudo_warnx(U_("only root can use \"-c %s\""), login_class);
ret = false;
goto done;
}
} else {
login_class = pw->pw_class;
if (!login_class || !*login_class)
login_class =
(pw->pw_uid == 0) ? LOGIN_DEFROOTCLASS : LOGIN_DEFCLASS;
}
/* Make sure specified login class is valid. */
lc = login_getclass(login_class);
if (!lc || !lc->lc_class || strcmp(lc->lc_class, login_class) != 0) {
/*
* Don't make it an error if the user didn't specify the login
* class themselves. We do this because if login.conf gets
* corrupted we want the admin to be able to use sudo to fix it.
*/
log_warningx(errflags, N_("unknown login class: %s"), login_class);
def_use_loginclass = false;
if (login_class)
ret = false;
}
login_close(lc);
done:
debug_return_bool(ret);
}
#else
static bool
set_loginclass(struct passwd *pw)
{
return true;
}
#endif /* HAVE_LOGIN_CAP_H */
#ifndef AI_FQDN
# define AI_FQDN AI_CANONNAME
#endif
/*
* Look up the fully qualified domain name of host.
* Use AI_FQDN if available since "canonical" is not always the same as fqdn.
* Returns true on success, setting longp and shortp.
* Returns false on failure, longp and shortp are unchanged.
*/
static int
resolve_host(const char *host, char **longp, char **shortp)
{
struct addrinfo *res0, hint;
char *cp, *lname, *sname;
int ret;
debug_decl(resolve_host, SUDOERS_DEBUG_PLUGIN);
memset(&hint, 0, sizeof(hint));
hint.ai_family = PF_UNSPEC;
hint.ai_flags = AI_FQDN;
if ((ret = getaddrinfo(host, NULL, &hint, &res0)) != 0)
debug_return_int(ret);
if ((lname = strdup(res0->ai_canonname)) == NULL) {
freeaddrinfo(res0);
debug_return_int(EAI_MEMORY);
}
if ((cp = strchr(lname, '.')) != NULL) {
sname = strndup(lname, (size_t)(cp - lname));
if (sname == NULL) {
free(lname);
freeaddrinfo(res0);
debug_return_int(EAI_MEMORY);
}
} else {
sname = lname;
}
freeaddrinfo(res0);
*longp = lname;
*shortp = sname;
debug_return_int(0);
}
/*
* Look up the fully qualified domain name of user_host and user_runhost.
* Sets user_host, user_shost, user_runhost and user_srunhost.
*/
static bool
cb_fqdn(const union sudo_defs_val *sd_un)
{
bool remote;
int rc;
char *lhost, *shost;
debug_decl(cb_fqdn, SUDOERS_DEBUG_PLUGIN);
/* Nothing to do if fqdn flag is disabled. */
if (sd_un != NULL && !sd_un->flag)
debug_return_bool(true);
/* If the -h flag was given we need to resolve both host and runhost. */
remote = strcmp(user_runhost, user_host) != 0;
/* First resolve user_host, setting user_host and user_shost. */
if (resolve_host(user_host, &lhost, &shost) != 0) {
if ((rc = resolve_host(user_runhost, &lhost, &shost)) != 0) {
gai_log_warning(SLOG_SEND_MAIL|SLOG_RAW_MSG, rc,
N_("unable to resolve host %s"), user_host);
debug_return_bool(false);
}
}
if (user_shost != user_host)
free(user_shost);
free(user_host);
user_host = lhost;
user_shost = shost;
/* Next resolve user_runhost, setting user_runhost and user_srunhost. */
lhost = shost = NULL;
if (remote) {
if ((rc = resolve_host(user_runhost, &lhost, &shost)) != 0) {
gai_log_warning(SLOG_NO_LOG|SLOG_RAW_MSG, rc,
N_("unable to resolve host %s"), user_runhost);
debug_return_bool(false);
}
} else {
/* Not remote, just use user_host. */
if ((lhost = strdup(user_host)) != NULL) {
if (user_shost != user_host)
shost = strdup(user_shost);
else
shost = lhost;
}
if (lhost == NULL || shost == NULL) {
free(lhost);
if (lhost != shost)
free(shost);
sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
debug_return_bool(false);
}
}
if (lhost != NULL && shost != NULL) {
if (user_srunhost != user_runhost)
free(user_srunhost);
free(user_runhost);
user_runhost = lhost;
user_srunhost = shost;
}
sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
"host %s, shost %s, runhost %s, srunhost %s",
user_host, user_shost, user_runhost, user_srunhost);
debug_return_bool(true);
}
/*
* Get passwd entry for the user we are going to run commands as
* and store it in runas_pw. By default, commands run as "root".
*/
static bool
set_runaspw(const char *user, bool quiet)
{
struct passwd *pw = NULL;
debug_decl(set_runaspw, SUDOERS_DEBUG_PLUGIN);
unknown_runas_uid = false;
if (*user == '#') {
const char *errstr;
uid_t uid = sudo_strtoid(user + 1, &errstr);
if (errstr == NULL) {
if ((pw = sudo_getpwuid(uid)) == NULL) {
unknown_runas_uid = true;
pw = sudo_fakepwnam(user, user_gid);
}
}
}
if (pw == NULL) {
if ((pw = sudo_getpwnam(user)) == NULL) {
if (!quiet)
log_warningx(SLOG_RAW_MSG, N_("unknown user: %s"), user);
debug_return_bool(false);
}
}
if (runas_pw != NULL)
sudo_pw_delref(runas_pw);
runas_pw = pw;
debug_return_bool(true);
}
/*
* Get group entry for the group we are going to run commands as
* and store it in runas_gr.
*/
static bool
set_runasgr(const char *group, bool quiet)
{
struct group *gr = NULL;
debug_decl(set_runasgr, SUDOERS_DEBUG_PLUGIN);
unknown_runas_gid = false;
if (*group == '#') {
const char *errstr;
gid_t gid = sudo_strtoid(group + 1, &errstr);
if (errstr == NULL) {
if ((gr = sudo_getgrgid(gid)) == NULL) {
unknown_runas_gid = true;
gr = sudo_fakegrnam(group);
}
}
}
if (gr == NULL) {
if ((gr = sudo_getgrnam(group)) == NULL) {
if (!quiet)
log_warningx(SLOG_RAW_MSG, N_("unknown group: %s"), group);
debug_return_bool(false);
}
}
if (runas_gr != NULL)
sudo_gr_delref(runas_gr);
runas_gr = gr;
debug_return_bool(true);
}
/*
* Callback for runas_default sudoers setting.
*/
static bool
cb_runas_default(const union sudo_defs_val *sd_un)
{
debug_decl(cb_runas_default, SUDOERS_DEBUG_PLUGIN);
/* Only reset runaspw if user didn't specify one. */
if (!runas_user && !runas_group)
debug_return_bool(set_runaspw(sd_un->str, true));
debug_return_bool(true);
}
/*
* Callback for tty_tickets sudoers setting.
*/
static bool
cb_tty_tickets(const union sudo_defs_val *sd_un)
{
debug_decl(cb_tty_tickets, SUDOERS_DEBUG_PLUGIN);
/* Convert tty_tickets -> timestamp_type */
if (sd_un->flag)
def_timestamp_type = tty;
else
def_timestamp_type = global;
debug_return_bool(true);
}
/*
* Callback for umask sudoers setting.
*/
static bool
cb_umask(const union sudo_defs_val *sd_un)
{
debug_decl(cb_umask, SUDOERS_DEBUG_PLUGIN);
/* Force umask if explicitly set in sudoers. */
force_umask = sd_un->mode != ACCESSPERMS;
debug_return_bool(true);
}
/*
* Callback for runchroot sudoers setting.
*/
static bool
cb_runchroot(const union sudo_defs_val *sd_un)
{
debug_decl(cb_runchroot, SUDOERS_DEBUG_PLUGIN);
sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
"def_runchroot now %s", sd_un->str);
if (user_cmnd != NULL) {
/* Update user_cmnd based on the new chroot. */
cmnd_status = set_cmnd_path(sd_un->str);
sudo_debug_printf(SUDO_DEBUG_INFO|SUDO_DEBUG_LINENO,
"user_cmnd now %s", user_cmnd);
}
debug_return_bool(true);
}
/*
* Cleanup hook for sudo_fatal()/sudo_fatalx()
*/
void
sudoers_cleanup(void)
{
struct sudo_nss *nss;
debug_decl(sudoers_cleanup, SUDOERS_DEBUG_PLUGIN);
if (snl != NULL) {
TAILQ_FOREACH(nss, snl, entries) {
nss->close(nss);
}
}
if (def_group_plugin)
group_plugin_unload();
sudo_freepwcache();
sudo_freegrcache();
debug_return;
}
#ifdef USE_ADMIN_FLAG
static int
create_admin_success_flag(void)
{
char flagfile[PATH_MAX];
int len, ret = -1;
debug_decl(create_admin_success_flag, SUDOERS_DEBUG_PLUGIN);
/* Check whether the user is in the sudo or admin group. */
if (!user_in_group(sudo_user.pw, "sudo") &&
!user_in_group(sudo_user.pw, "admin"))
debug_return_int(true);
/* Build path to flag file. */
len = snprintf(flagfile, sizeof(flagfile), "%s/.sudo_as_admin_successful",
user_dir);
if (len < 0 || len >= ssizeof(flagfile))
debug_return_int(false);
/* Create admin flag file if it doesn't already exist. */
if (set_perms(PERM_USER)) {
int fd = open(flagfile, O_CREAT|O_WRONLY|O_NONBLOCK|O_EXCL, 0644);
ret = fd != -1 || errno == EEXIST;
if (fd != -1)
close(fd);
if (!restore_perms())
ret = -1;
}
debug_return_int(ret);
}
#else /* !USE_ADMIN_FLAG */
static int
create_admin_success_flag(void)
{
/* STUB */
return true;
}
#endif /* USE_ADMIN_FLAG */
static bool
tty_present(void)
{
debug_decl(tty_present, SUDOERS_DEBUG_PLUGIN);
if (user_ttypath == NULL) {
int fd = open(_PATH_TTY, O_RDWR);
if (fd == -1)
debug_return_bool(false);
close(fd);
}
debug_return_bool(true);
}
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