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/* passwd.c - Program to update user password.
*
* Copyright 2012 Ashwini Kumar <ak.ashwini@gmail.com>
* Modified 2012 Jason Kyungwan Han <asura321@gmail.com>
*
* http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/passwd.html
USE_PASSWD(NEWTOY(passwd, ">1a:dlu", TOYFLAG_STAYROOT|TOYFLAG_USR|TOYFLAG_BIN))
config PASSWD
bool "passwd"
default y
depends on TOYBOX_SHADOW
help
usage: passwd [-a ALGO] [-dlu] <account name>
update user's authentication tokens. Default : current user
-a ALGO Encryption method (des, md5, sha256, sha512) default: des
-d Set password to ''
-l Lock (disable) account
-u Unlock (enable) account
config PASSWD_SAD
bool "Add sad password checking heuristics"
default n
depends on PASSWD
help
Password changes are checked to make sure they don't include the entire
username (but not a subset of it), and the entire previous password
(but changing password1, password2, password3 is fine). This heuristic
accepts "aaaaaa" as a password.
*/
#define FOR_passwd
#include "toys.h"
GLOBALS(
char *algo;
)
static int str_check(char *s, char *p)
{
if (strnstr(s, p) || strnstr(p, s)) return 1;
return 0;
}
// Insane heuristic won't find password1 password2 password3...?
static void strength_check(char *newp, char *oldp, char *user)
{
char *msg = NULL;
if (strlen(newp) < 6) { //Min passwd len
msg = "too short";
xprintf("BAD PASSWORD: %s\n",msg);
}
if (!newp[0]) return; //passwd is empty
if (str_check(newp, user)) {
msg = "user based password";
xprintf("BAD PASSWORD: %s\n",msg);
}
if (oldp[0] && str_check(newp, oldp)) {
msg = "based on old passwd";
xprintf("BAD PASSWORD: %s\n",msg);
}
}
static int verify_passwd(char * pwd)
{
char * pass;
if (!pwd) return 1;
if (pwd[0] == '!' || pwd[0] == '*') return 1;
pass = crypt(toybuf, pwd);
if (pass && !strcmp(pass, pwd)) return 0;
return 1;
}
static char *new_password(char *oldp, char *user)
{
char *newp = NULL;
if (read_password(toybuf, sizeof(toybuf), "New password:"))
return NULL; //may be due to Ctrl-C
newp = xstrdup(toybuf);
if (CFG_PASSWD_SAD) strength_check(newp, oldp, user);
if (read_password(toybuf, sizeof(toybuf), "Retype password:")) {
free(newp);
return NULL; //may be due to Ctrl-C
}
if (!strcmp(newp, toybuf)) return newp;
else error_msg("Passwords do not match.\n");
// Failure Case
free(newp);
return NULL;
}
void passwd_main(void)
{
uid_t myuid;
struct passwd *pw;
struct spwd *sp;
char *name = NULL, *pass = NULL, *encrypted = NULL, *newp = NULL,
*orig = (char *)"", salt[MAX_SALT_LEN];
int ret = -1;
myuid = getuid();
if (myuid && (toys.optflags & (FLAG_l | FLAG_u | FLAG_d)))
error_exit("Not root");
pw = xgetpwuid(myuid);
if (*toys.optargs) name = toys.optargs[0];
else name = xstrdup(pw->pw_name);
pw = xgetpwnam(name);
if (myuid && (myuid != pw->pw_uid)) error_exit("Not root");
pass = pw->pw_passwd;
if (pw->pw_passwd[0] == 'x') {
//get shadow passwd
sp = getspnam(name);
if (sp) pass = sp->sp_pwdp;
}
if (!(toys.optflags & (FLAG_l | FLAG_u | FLAG_d))) {
if (!(toys.optflags & FLAG_a)) TT.algo = "des";
if (get_salt(salt, TT.algo) == -1)
error_exit("Error: Unkown encryption algorithm\n");
printf("Changing password for %s\n",name);
if (myuid && pass[0] == '!')
error_exit("Can't change, password is locked for %s",name);
if (myuid) {
//Validate user
if (read_password(toybuf, sizeof(toybuf), "Origial password:")) {
if (!toys.optargs[0]) free(name);
return;
}
orig = toybuf;
if (verify_passwd(pass)) error_exit("Authentication failed\n");
}
orig = xstrdup(orig);
// Get new password
newp = new_password(orig, name);
if (!newp) {
free(orig);
if (!toys.optargs[0]) free(name);
return; //new password is not set well.
}
encrypted = crypt(newp, salt);
free(newp);
free(orig);
} else if (toys.optflags & FLAG_l) {
if (pass[0] == '!') error_exit("password is already locked for %s",name);
printf("Locking password for %s\n",name);
encrypted = xmprintf("!%s",pass);
} else if (toys.optflags & FLAG_u) {
if (pass[0] != '!') error_exit("password is already unlocked for %s",name);
printf("Unlocking password for %s\n",name);
encrypted = xstrdup(&pass[1]);
} else if (toys.optflags & FLAG_d) {
printf("Deleting password for %s\n",name);
encrypted = xstrdup(""); //1 = "", 2 = '\0'
}
// Update the passwd
if (pw->pw_passwd[0] == 'x')
ret = update_password("/etc/shadow", name, encrypted);
else ret = update_password("/etc/passwd", name, encrypted);
if ((toys.optflags & (FLAG_l | FLAG_u | FLAG_d))) free(encrypted);
if (!toys.optargs[0]) free(name);
if (!ret) error_msg("Success");
else error_msg("Failure");
}
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