loginutils/chpasswd.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * chpasswd.c
   4  *
   5  * Written for SLIND (from passwd.c) by Alexander Shishkin <virtuoso@slind.org>
   6  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   7  */
   8 //config:config CHPASSWD
   9 //config:       bool "chpasswd (18 kb)"
  10 //config:       default y
  11 //config:       help
  12 //config:       Reads a file of user name and password pairs from standard input
  13 //config:       and uses this information to update a group of existing users.
  14 //config:
  15 //config:config FEATURE_DEFAULT_PASSWD_ALGO
  16 //config:       string "Default encryption method (passwd -a, cryptpw -m, chpasswd -c ALG)"
  17 //config:       default "des"
  18 //config:       depends on PASSWD || CRYPTPW || CHPASSWD
  19 //config:       help
  20 //config:       Possible choices are "d[es]", "m[d5]", "s[ha256]" or "sha512".
  21
  22 //applet:IF_CHPASSWD(APPLET(chpasswd, BB_DIR_USR_SBIN, BB_SUID_DROP))
  23
  24 //kbuild:lib-$(CONFIG_CHPASSWD) += chpasswd.o
  25
  26 //usage:#define chpasswd_trivial_usage
  27 //usage:        IF_LONG_OPTS("[--md5|--encrypted|--crypt-method|--root]") IF_NOT_LONG_OPTS("[-m|-e|-c|-R]")
  28 //usage:#define chpasswd_full_usage "\n\n"
  29 //usage:       "Read user:password from stdin and update /etc/passwd\n"
  30 //usage:        IF_LONG_OPTS(
  31 //usage:     "\n        -e,--encrypted          Supplied passwords are in encrypted form"
  32 //usage:     "\n        -m,--md5                Encrypt using md5, not des"
  33 //usage:     "\n        -c,--crypt-method ALG   "CRYPT_METHODS_HELP_STR
  34 //usage:     "\n        -R,--root DIR           Directory to chroot into"
  35 //usage:        )
  36 //usage:        IF_NOT_LONG_OPTS(
  37 //usage:     "\n        -e      Supplied passwords are in encrypted form"
  38 //usage:     "\n        -m      Encrypt using md5, not des"
  39 //usage:     "\n        -c ALG  "CRYPT_METHODS_HELP_STR
  40 //usage:     "\n        -R DIR  Directory to chroot into"
  41 //usage:        )
  42
  43 #include "libbb.h"
  44
  45 #if ENABLE_LONG_OPTS
  46 static const char chpasswd_longopts[] ALIGN1 =
  47         "encrypted\0"    No_argument       "e"
  48         "md5\0"          No_argument       "m"
  49         "crypt-method\0" Required_argument "c"
  50         "root\0"         Required_argument "R"
  51         ;
  52 #endif
  53
  54 #define OPT_ENC  1
  55 #define OPT_MD5  2
  56
  57 int chpasswd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  58 int chpasswd_main(int argc UNUSED_PARAM, char **argv)
  59 {
  60         char *name;
  61         const char *algo = CONFIG_FEATURE_DEFAULT_PASSWD_ALGO;
  62         const char *root = NULL;
  63         int opt;
  64
  65         if (getuid() != 0)
  66                 bb_error_msg_and_die(bb_msg_perm_denied_are_you_root);
  67
  68         opt = getopt32long(argv, "^" "emc:R:" "\0" "m--ec:e--mc:c--em",
  69                         chpasswd_longopts,
  70                         &algo, &root
  71         );
  72
  73         if (root) {
  74                 xchroot(root);
  75         }
  76
  77         while ((name = xmalloc_fgetline(stdin)) != NULL) {
  78                 char *free_me;
  79                 char *pass;
  80                 int rc;
  81
  82                 pass = strchr(name, ':');
  83                 if (!pass)
  84                         bb_error_msg_and_die("missing new password");
  85                 *pass++ = '\0';
  86
  87                 xuname2uid(name); /* dies if there is no such user */
  88
  89                 free_me = NULL;
  90                 if (!(opt & OPT_ENC)) {
  91                         char salt[MAX_PW_SALT_LEN];
  92
  93                         if (opt & OPT_MD5) {
  94                                 /* Force MD5 if the -m flag is set */
  95                                 algo = "md5";
  96                         }
  97
  98                         crypt_make_pw_salt(salt, algo);
  99                         free_me = pass = pw_encrypt(pass, salt, 0);
 100                 }
 101
 102                 /* This is rather complex: if user is not found in /etc/shadow,
 103                  * we try to find & change his passwd in /etc/passwd */
 104 #if ENABLE_FEATURE_SHADOWPASSWDS
 105                 rc = update_passwd(bb_path_shadow_file, name, pass, NULL);
 106                 if (rc > 0) /* password in /etc/shadow was updated */
 107                         pass = (char*)"x";
 108                 if (rc >= 0)
 109                         /* 0 = /etc/shadow missing (not an error), >0 = passwd changed in /etc/shadow */
 110 #endif
 111                         rc = update_passwd(bb_path_passwd_file, name, pass, NULL);
 112                 /* LOGMODE_BOTH logs to syslog also */
 113                 logmode = LOGMODE_BOTH;
 114                 if (rc < 0)
 115                         bb_error_msg_and_die("an error occurred updating password for %s", name);
 116                 if (rc)
 117                         bb_error_msg("password for '%s' changed", name);
 118                 logmode = LOGMODE_STDIO;
 119                 free(name);
 120                 free(free_me);
 121         }
 122         return EXIT_SUCCESS;
 123 }