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/* vi: set sw=4 ts=4: */
/*
* Licensed under GPLv2 or later, see file LICENSE in this source tree.
*/
//config:config PASSWD
//config: bool "passwd (21 kb)"
//config: default y
//config: select FEATURE_SYSLOG
//config: help
//config: passwd changes passwords for user and group accounts. A normal user
//config: may only change the password for his/her own account, the super user
//config: may change the password for any account. The administrator of a group
//config: may change the password for the group.
//config:
//config: Note that busybox binary must be setuid root for this applet to
//config: work properly.
//config:
//config:config FEATURE_PASSWD_WEAK_CHECK
//config: bool "Check new passwords for weakness"
//config: default y
//config: depends on PASSWD
//config: help
//config: With this option passwd will refuse new passwords which are "weak".
//applet:/* Needs to be run by root or be suid root - needs to change /etc/{passwd,shadow}: */
//applet:IF_PASSWD(APPLET(passwd, BB_DIR_USR_BIN, BB_SUID_REQUIRE))
//kbuild:lib-$(CONFIG_PASSWD) += passwd.o
//usage:#define passwd_trivial_usage
//usage: "[OPTIONS] [USER]"
//usage:#define passwd_full_usage "\n\n"
//usage: "Change USER's password (default: current user)"
//usage: "\n"
//usage: "\n -a ALG "CRYPT_METHODS_HELP_STR
//usage: "\n -d Set password to ''"
//usage: "\n -l Lock (disable) account"
//usage: "\n -u Unlock (enable) account"
#include "libbb.h"
#include <syslog.h>
static char* new_password(const struct passwd *pw, uid_t myuid, const char *algo)
{
char salt[MAX_PW_SALT_LEN];
char *orig = NULL;
char *newp = NULL;
char *cp = NULL;
char *ret = NULL; /* failure so far */
if (myuid != 0 && pw->pw_passwd[0]) {
char *encrypted;
orig = bb_ask_noecho_stdin("Old password: "); /* returns malloced str */
if (!orig)
goto err_ret;
encrypted = pw_encrypt(orig, pw->pw_passwd, 1); /* returns malloced str */
if (strcmp(encrypted, pw->pw_passwd) != 0) {
syslog(LOG_WARNING, "incorrect password for %s", pw->pw_name);
bb_do_delay(LOGIN_FAIL_DELAY);
puts("Incorrect password");
goto err_ret;
}
if (ENABLE_FEATURE_CLEAN_UP)
free(encrypted);
}
newp = bb_ask_noecho_stdin("New password: "); /* returns malloced str */
if (!newp)
goto err_ret;
if (ENABLE_FEATURE_PASSWD_WEAK_CHECK
&& obscure(orig, newp, pw) /* NB: passing NULL orig is ok */
&& myuid != 0
) {
goto err_ret; /* non-root is not allowed to have weak passwd */
}
cp = bb_ask_noecho_stdin("Retype password: ");
if (!cp)
goto err_ret;
if (strcmp(cp, newp) != 0) {
puts("Passwords don't match");
goto err_ret;
}
crypt_make_pw_salt(salt, algo);
/* pw_encrypt returns malloced str */
ret = pw_encrypt(newp, salt, 1);
/* whee, success! */
err_ret:
nuke_str(orig);
if (ENABLE_FEATURE_CLEAN_UP) free(orig);
nuke_str(newp);
if (ENABLE_FEATURE_CLEAN_UP) free(newp);
nuke_str(cp);
if (ENABLE_FEATURE_CLEAN_UP) free(cp);
return ret;
}
int passwd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int passwd_main(int argc UNUSED_PARAM, char **argv)
{
enum {
OPT_algo = (1 << 0), /* -a - password algorithm */
OPT_lock = (1 << 1), /* -l - lock account */
OPT_unlock = (1 << 2), /* -u - unlock account */
OPT_delete = (1 << 3), /* -d - delete password */
OPT_lud = OPT_lock | OPT_unlock | OPT_delete,
};
unsigned opt;
int rc;
const char *opt_a = CONFIG_FEATURE_DEFAULT_PASSWD_ALGO;
const char *filename;
char *myname;
char *name;
char *newp;
struct passwd *pw;
uid_t myuid;
struct rlimit rlimit_fsize;
char c;
#if ENABLE_FEATURE_SHADOWPASSWDS
/* Using _r function to avoid pulling in static buffers */
struct spwd spw;
char buffer[256];
#endif
logmode = LOGMODE_BOTH;
openlog(applet_name, 0, LOG_AUTH);
opt = getopt32(argv, "a:lud", &opt_a);
//argc -= optind;
argv += optind;
myuid = getuid();
/* -l, -u, -d require root priv and username argument */
if ((opt & OPT_lud) && (myuid != 0 || !argv[0]))
bb_show_usage();
/* Will complain and die if username not found */
myname = xstrdup(xuid2uname(myuid));
name = argv[0] ? argv[0] : myname;
pw = xgetpwnam(name);
if (myuid != 0 && pw->pw_uid != myuid) {
/* LOGMODE_BOTH */
bb_error_msg_and_die("%s can't change password for %s", myname, name);
}
#if ENABLE_FEATURE_SHADOWPASSWDS
{
/* getspnam_r may return 0 yet set result to NULL.
* At least glibc 2.4 does this. Be extra paranoid here. */
struct spwd *result = NULL;
errno = 0;
if (getspnam_r(pw->pw_name, &spw, buffer, sizeof(buffer), &result) != 0
|| !result /* no error, but no record found either */
|| strcmp(result->sp_namp, pw->pw_name) != 0 /* paranoia */
) {
if (errno != ENOENT) {
/* LOGMODE_BOTH */
bb_perror_msg("no record of %s in %s, using %s",
name, bb_path_shadow_file,
bb_path_passwd_file);
}
/* else: /etc/shadow does not exist,
* apparently we are on a shadow-less system,
* no surprise there */
} else {
pw->pw_passwd = result->sp_pwdp;
}
}
#endif
/* Decide what the new password will be */
newp = NULL;
c = pw->pw_passwd[0] - '!';
if (!(opt & OPT_lud)) {
if (myuid != 0 && !c) { /* passwd starts with '!' */
/* LOGMODE_BOTH */
bb_error_msg_and_die("can't change "
"locked password for %s", name);
}
printf("Changing password for %s\n", name);
newp = new_password(pw, myuid, opt_a);
if (!newp) {
logmode = LOGMODE_STDIO;
bb_error_msg_and_die("password for %s is unchanged", name);
}
} else if (opt & OPT_lock) {
if (!c)
goto skip; /* passwd starts with '!' */
newp = xasprintf("!%s", pw->pw_passwd);
} else if (opt & OPT_unlock) {
if (c)
goto skip; /* not '!' */
/* pw->pw_passwd points to static storage,
* strdup'ing to avoid nasty surprizes */
newp = xstrdup(&pw->pw_passwd[1]);
} else if (opt & OPT_delete) {
newp = (char*)"";
}
rlimit_fsize.rlim_cur = rlimit_fsize.rlim_max = 512L * 30000;
setrlimit(RLIMIT_FSIZE, &rlimit_fsize);
bb_signals(0
+ (1 << SIGHUP)
+ (1 << SIGINT)
+ (1 << SIGQUIT)
, SIG_IGN);
umask(077);
xsetuid(0);
#if ENABLE_FEATURE_SHADOWPASSWDS
filename = bb_path_shadow_file;
rc = update_passwd(bb_path_shadow_file, name, newp, NULL);
if (rc > 0)
/* password in /etc/shadow was updated */
newp = (char*) "x";
if (rc >= 0)
/* 0 = /etc/shadow missing (not an error), >0 = passwd changed in /etc/shadow */
#endif
{
filename = bb_path_passwd_file;
rc = update_passwd(bb_path_passwd_file, name, newp, NULL);
}
/* LOGMODE_BOTH */
if (rc < 0)
bb_error_msg_and_die("can't update password file %s", filename);
bb_error_msg("password for %s changed by %s", name, myname);
/*if (ENABLE_FEATURE_CLEAN_UP) free(newp); - can't, it may be non-malloced */
skip:
if (!newp) {
bb_error_msg_and_die("password for %s is already %slocked",
name, (opt & OPT_unlock) ? "un" : "");
}
if (ENABLE_FEATURE_CLEAN_UP)
free(myname);
return 0;
}
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