LXR toybox/toys/lsb/su.c

   1/* su.c - switch user
   2 *
   3 * Copyright 2013 CE Strake <strake888@gmail.com>
   4 *
   5 * See http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/su.html
   6 * TODO: log su attempts
   7 * TODO: suid support
   8 * Supports undocumented compatibility options: -m synonym for -p, - for -l
   9
  10USE_SU(NEWTOY(su, "^lmpu:g:c:s:[!lmp]", TOYFLAG_BIN|TOYFLAG_ROOTONLY))
  11
  12config SU
  13  bool "su"
  14  default y
  15  depends on TOYBOX_SHADOW
  16  help
  17    usage: su [-lp] [-u UID] [-g GID,...] [-s SHELL] [-c CMD] [USER [COMMAND...]]
  18
  19    Switch user, prompting for password of new user when not run as root.
  20
  21    With one argument, switch to USER and run user's shell from /etc/passwd.
  22    With no arguments, USER is root. If COMMAND line provided after USER,
  23    exec() it as new USER (bypasing shell). If -u or -g specified, first
  24    argument (if any) isn't USER (it's COMMAND).
  25
  26    first argument is USER name to switch to (which must exist).
  27    Non-root users are prompted for new user's password.
  28
  29    -s  Shell to use (default is user's shell from /etc/passwd)
  30    -c  Command line to pass to -s shell (ala sh -c "CMD")
  31    -l  Reset environment as if new login.
  32    -u  Switch to UID instead of USER
  33    -g  Switch to GID (only root allowed, can be comma separated list)
  34    -p  Preserve environment (except for $PATH and $IFS)
  35*/
  36
  37#define FOR_su
  38#include "toys.h"
  39
  40GLOBALS(
  41  char *s;
  42  char *c;
  43)
  44
  45void su_main()
  46{
  47  char *name, *passhash = 0, **argu, **argv;
  48  struct passwd *up;
  49  struct spwd *shp;
  50
  51  if (*toys.optargs && !strcmp("-", *toys.optargs)) {
  52    toys.optflags |= FLAG_l;
  53    toys.optargs++;
  54  }
  55
  56  if (*toys.optargs) name = *(toys.optargs++);
  57  else name = "root";
  58
  59  loggit(LOG_NOTICE, "%s->%s", getusername(getuid()), name);
  60
  61  if (!(shp = getspnam(name))) perror_exit("no '%s'", name);
  62  if (getuid()) {
  63    if (*shp->sp_pwdp != '$') goto deny;
  64    if (read_password(toybuf, sizeof(toybuf), "Password: ")) goto deny;
  65    passhash = crypt(toybuf, shp->sp_pwdp);
  66    memset(toybuf, 0, sizeof(toybuf));
  67    if (!passhash || strcmp(passhash, shp->sp_pwdp)) goto deny;
  68  }
  69  closelog();
  70
  71  xsetuser(up = xgetpwnam(name));
  72
  73  if (FLAG(m)||FLAG(p)) {
  74    unsetenv("IFS");
  75    setenv("PATH", _PATH_DEFPATH, 1);
  76  } else reset_env(up, FLAG(l));
  77
  78  argv = argu = xmalloc(sizeof(char *)*(toys.optc + 4));
  79  *(argv++) = TT.s ? TT.s : up->pw_shell;
  80  loggit(LOG_NOTICE, "run %s", *argu);
  81
  82  if (FLAG(l)) *(argv++) = "-l";
  83  if (FLAG(c)) {
  84    *(argv++) = "-c";
  85    *(argv++) = TT.c;
  86  }
  87  while ((*(argv++) = *(toys.optargs++)));
  88  xexec(argu);
  89
  90deny:
  91  syslog(LOG_NOTICE, "No.");
  92  puts("No.");
  93  toys.exitval = 1;
  94}
  95