release/src/router/busybox/libbb/die_if_bad_username.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Check user and group names for illegal characters
   4  *
   5  * Copyright (C) 2008 Tito Ragusa <farmatito@tiscali.it>
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8  */
   9
  10 #include "libbb.h"
  11
  12 /* To avoid problems, the username should consist only of
  13  * letters, digits, underscores, periods, at signs and dashes,
  14  * and not start with a dash (as defined by IEEE Std 1003.1-2001).
  15  * For compatibility with Samba machine accounts $ is also supported
  16  * at the end of the username.
  17  */
  18
  19 void FAST_FUNC die_if_bad_username(const char *name)
  20 {
  21         /* 1st char being dash or dot isn't valid: */
  22         goto skip;
  23         /* For example, name like ".." can make adduser
  24          * chown "/home/.." recursively - NOT GOOD
  25          */
  26
  27         do {
  28                 if (*name == '-' || *name == '.')
  29                         continue;
  30  skip:
  31                 if (isalnum(*name)
  32                  || *name == '_'
  33                  || *name == '@'
  34                  || (*name == '$' && !name[1])
  35                 ) {
  36                         continue;
  37                 }
  38                 bb_error_msg_and_die("illegal character '%c'", *name);
  39         } while (*++name);
  40 }