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1004
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1 /* su.c - switch user
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2 *
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3 * Copyright 2013 CE Strake <strake888@gmail.com>
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4 *
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5 * See http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/su.html
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6
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7 USE_SU(NEWTOY(su, "lmpc:s:", TOYFLAG_BIN))
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8
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9 config SU
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10 bool "su"
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11 default n
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12 help
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13 usage: su [-lmp] [-c cmd] [-s shell] [user [argu...]]
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14
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15 Switch to given user, or root if not given, and call a shell with the given arguments.
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16
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17 options:
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18 -s shell to call
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19 -c command to pass to shell with -c
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20
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21 flags:
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22 -l login shell
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23 -(m|p) preserve environment
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24 */
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25
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26 #define FOR_su
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27 #include "toys.h"
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28
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29 GLOBALS(
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30 char *sArgu;
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31 char *cArgu;
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32 )
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33
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34 extern char **environ;
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35
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36 static void deny () {
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37 printf ("Denied\n");
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38 xexit ();
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39 }
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40
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41 void su_main () {
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42 char *name, *passhash, **argu, **argv;
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43 struct passwd *up;
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44 struct spwd *shp;
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45 long ii;
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46
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47 if (toys.optc && strcmp ("-", toys.optargs[0]) == 0) {
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48 toys.optflags |= FLAG_l;
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49 toys.optc--; toys.optargs++;
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50 }
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51
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52 if (toys.optc) {
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53 name = toys.optargs[0];
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54 toys.optc--; toys.optargs++;
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55 }
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56 else name = "root";
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57 shp = getspnam (name);
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58 if (!shp) perror_exit ("failed to find password");
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59
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60 switch (shp -> sp_pwdp[0]) {
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61 case '!': deny ();
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62 case '$': break;
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63 default : error_exit ("bad password format");
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64 }
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65
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66 if (read_password (toybuf, sizeof (toybuf), "Password: ") != 0) perror_exit ("failed to read password");
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67
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68 passhash = crypt (toybuf, shp -> sp_pwdp);
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69 if (!passhash) perror_exit ("failed to compute password hash");
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70 for (ii = 0; toybuf[ii]; ii++) toybuf[ii] = 0;
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71
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72 if (strcmp (passhash, shp -> sp_pwdp) != 0) deny ();
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73
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74 up = getpwnam (name);
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75 if (!up) perror_exit ("failed to getpwnam");
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76
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77 if (setuid (up -> pw_uid) < 0) perror_exit ("failed to setuid");
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78 if (chdir (up -> pw_dir) < 0) perror_exit ("failed to chdir");
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79
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80 argu = xmalloc (sizeof (char *)*(toys.optc + 4));
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81 argv = argu;
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82 argv[0] = toys.optflags & FLAG_s ? TT.sArgu : up -> pw_shell;
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83 if (toys.optflags & FLAG_c) {
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84 argv[1] = toys.optflags & FLAG_l ? "-lc" : "-c";
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85 argv[2] = TT.cArgu;
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86 argv += 2;
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87 }
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88 else if (toys.optflags & FLAG_l) (argv++)[1] = "-l";
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89 for (ii = 0; ii < toys.optc; ii++) argv[ii + 1] = toys.optargs[ii];
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90 if (execve (argu[0], argu,
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91 toys.optflags & FLAG_l ? (char *[]){
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92 xmsprintf ( "HOME=%s", up -> pw_dir),
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93 xmsprintf ("SHELL=%s", up -> pw_shell),
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94 xmsprintf ( "USER=%s", up -> pw_name),
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95 xmsprintf ( "TERM=%s", getenv ("TERM")),
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96 0
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97 } : environ) < 0) perror_exit ("failed to exec %s", argu[0]);
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98 }
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