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/* su.c - switch user
*
* Copyright 2013 CE Strake <strake888@gmail.com>
*
* See http://refspecs.linuxfoundation.org/LSB_4.1.0/LSB-Core-generic/LSB-Core-generic/su.html
USE_SU(NEWTOY(su, "lmpc:s:", TOYFLAG_BIN))
config SU
bool "su"
default n
help
usage: su [-lmp] [-c cmd] [-s shell] [user [argu...]]
Switch to given user, or root if not given, and call a shell with the given arguments.
options:
-s shell to call
-c command to pass to shell with -c
flags:
-l login shell
-(m|p) preserve environment
*/
#define FOR_su
#include "toys.h"
GLOBALS(
char *sArgu;
char *cArgu;
)
extern char **environ;
static void deny () {
printf ("Denied\n");
xexit ();
}
void su_main () {
char *name, *passhash, **argu, **argv;
struct passwd *up;
struct spwd *shp;
long ii;
if (toys.optc && strcmp ("-", toys.optargs[0]) == 0) {
toys.optflags |= FLAG_l;
toys.optc--; toys.optargs++;
}
if (toys.optc) {
name = toys.optargs[0];
toys.optc--; toys.optargs++;
}
else name = "root";
shp = getspnam (name);
if (!shp) perror_exit ("failed to find password");
switch (shp -> sp_pwdp[0]) {
case '!': deny ();
case '$': break;
default : error_exit ("bad password format");
}
if (read_password (toybuf, sizeof (toybuf), "Password: ") != 0) perror_exit ("failed to read password");
passhash = crypt (toybuf, shp -> sp_pwdp);
if (!passhash) perror_exit ("failed to compute password hash");
for (ii = 0; toybuf[ii]; ii++) toybuf[ii] = 0;
if (strcmp (passhash, shp -> sp_pwdp) != 0) deny ();
up = getpwnam (name);
if (!up) perror_exit ("failed to getpwnam");
if (setuid (up -> pw_uid) < 0) perror_exit ("failed to setuid");
if (chdir (up -> pw_dir) < 0) perror_exit ("failed to chdir");
argu = xmalloc (sizeof (char *)*(toys.optc + 4));
argv = argu;
argv[0] = toys.optflags & FLAG_s ? TT.sArgu : up -> pw_shell;
if (toys.optflags & FLAG_c) {
argv[1] = toys.optflags & FLAG_l ? "-lc" : "-c";
argv[2] = TT.cArgu;
argv += 2;
}
else if (toys.optflags & FLAG_l) (argv++)[1] = "-l";
for (ii = 0; ii < toys.optc; ii++) argv[ii + 1] = toys.optargs[ii];
if (execve (argu[0], argu,
toys.optflags & FLAG_l ? (char *[]){
xmsprintf ( "HOME=%s", up -> pw_dir),
xmsprintf ("SHELL=%s", up -> pw_shell),
xmsprintf ( "USER=%s", up -> pw_name),
xmsprintf ( "TERM=%s", getenv ("TERM")),
0
} : environ) < 0) perror_exit ("failed to exec %s", argu[0]);
}
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