| /* 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 |
| help |
| usage: passwd [-a ALGO] [-d] [-l] [-u] <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 |
| */ |
| |
| #define FOR_passwd |
| #include "toys.h" |
| #include <time.h> |
| |
| GLOBALS( |
| char *algo; |
| ) |
| |
| #define MAX_SALT_LEN 20 //3 for id, 16 for key, 1 for '\0' |
| #define URANDOM_PATH "/dev/urandom" |
| |
| #ifndef _GNU_SOURCE |
| char *strcasestr(const char *haystack, const char *needle); |
| #endif |
| |
| unsigned int random_number_generator(int fd) |
| { |
| unsigned int randnum; |
| xreadall(fd, &randnum, sizeof(randnum)); |
| return randnum; |
| } |
| |
| char inttoc(int i) |
| { |
| // salt value uses 64 chracters in "./0-9a-zA-Z" |
| const char character_set[]="./0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"; |
| i &= 0x3f; // masking for using 10 bits only |
| return character_set[i]; |
| } |
| |
| int get_salt(char *salt) |
| { |
| int i, salt_length = 0; |
| int randfd; |
| if(!strncmp(TT.algo,"des",3)){ |
| // 2 bytes salt value is used in des |
| salt_length = 2; |
| } else { |
| *salt++ = '$'; |
| if(!strncmp(TT.algo,"md5",3)){ |
| *salt++ = '1'; |
| // 8 bytes salt value is used in md5 |
| salt_length = 8; |
| } else if(!strncmp(TT.algo,"sha256",6)){ |
| *salt++ = '5'; |
| // 16 bytes salt value is used in sha256 |
| salt_length = 16; |
| } else if(!strncmp(TT.algo,"sha512",6)){ |
| *salt++ = '6'; |
| // 16 bytes salt value is used in sha512 |
| salt_length = 16; |
| } else return 1; |
| |
| *salt++ = '$'; |
| } |
| |
| randfd = xopen(URANDOM_PATH, O_RDONLY); |
| for(i=0; i<salt_length; i++) |
| salt[i] = inttoc(random_number_generator(randfd)); |
| salt[salt_length+1] = '\0'; |
| xclose(randfd); |
| |
| return 0; |
| } |
| |
| static int str_check(char *s, char *p) |
| { |
| if((strcasestr(s, p) != NULL) || (strcasestr(p, s) != NULL)) |
| return 1; |
| return 0; |
| } |
| |
| 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 != NULL && strcmp(pass, pwd)==0) |
| 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); |
| 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) == 0) |
| 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; |
| char *pass = NULL, *encrypted = NULL, *newp = NULL; |
| char *orig = (char *)""; |
| char salt[MAX_SALT_LEN]; |
| int ret = -1; |
| |
| myuid = getuid(); |
| if((myuid != 0) && (toys.optflags & (FLAG_l | FLAG_u | FLAG_d))) |
| error_exit("You need to be root to do these actions\n"); |
| |
| pw = getpwuid(myuid); |
| |
| if(!pw) |
| error_exit("Unknown uid '%u'",myuid); |
| |
| if(toys.optargs[0]) |
| name = toys.optargs[0]; |
| else |
| name = xstrdup(pw->pw_name); |
| |
| pw = getpwnam(name); |
| if(!pw) error_exit("Unknown user '%s'",name); |
| |
| if(myuid != 0 && (myuid != pw->pw_uid)) |
| error_exit("You need to be root to change '%s' password\n", name); |
| |
| 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))) { |
| printf("Changing password for %s\n",name); |
| if(pass[0] == '!') |
| error_exit("Can't change, password is locked for %s",name); |
| if(myuid != 0) { |
| /*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. |
| } |
| |
| /*Encrypt the passwd */ |
| if(!(toys.optflags & FLAG_a)) TT.algo = "des"; |
| |
| if(get_salt(salt)) |
| error_exit("Error: Unkown encryption algorithm\n"); |
| |
| 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 = xmsprintf("!%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 = (char*)xzalloc(sizeof(char)*2); //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"); |
| } |