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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
* TODO: log su attempts
* TODO: suid support
* Supports undocumented compatibility options: -m synonym for -p, - for -l
USE_SU(NEWTOY(su, "^lmpu:g:c:s:[!lmp]", TOYFLAG_BIN|TOYFLAG_ROOTONLY))
config SU
bool "su"
default y
depends on TOYBOX_SHADOW
help
usage: su [-lp] [-u UID] [-g GID,...] [-s SHELL] [-c CMD] [USER [COMMAND...]]
Switch user, prompting for password of new user when not run as root.
With one argument, switch to USER and run user's shell from /etc/passwd.
With no arguments, USER is root. If COMMAND line provided after USER,
exec() it as new USER (bypassing shell). If -u or -g specified, first
argument (if any) isn't USER (it's COMMAND).
first argument is USER name to switch to (which must exist).
Non-root users are prompted for new user's password.
-s Shell to use (default is user's shell from /etc/passwd)
-c Command line to pass to -s shell (ala sh -c "CMD")
-l Reset environment as if new login.
-u Switch to UID instead of USER
-g Switch to GID (only root allowed, can be comma separated list)
-p Preserve environment (except for $PATH and $IFS)
*/
#define FOR_su
#include "toys.h"
GLOBALS(
char *s;
char *c;
)
void su_main()
{
char *name, *passhash = 0, **argu, **argv;
struct passwd *up;
struct spwd *shp;
if (*toys.optargs && !strcmp("-", *toys.optargs)) {
toys.optflags |= FLAG_l;
toys.optargs++;
}
if (*toys.optargs) name = *(toys.optargs++);
else name = "root";
loggit(LOG_NOTICE, "%s->%s", getusername(getuid()), name);
if (!(shp = getspnam(name))) perror_exit("no '%s'", name);
if (getuid()) {
if (*shp->sp_pwdp != '$') goto deny;
if (read_password(toybuf, sizeof(toybuf), "Password: ")) goto deny;
passhash = crypt(toybuf, shp->sp_pwdp);
memset(toybuf, 0, sizeof(toybuf));
if (!passhash || strcmp(passhash, shp->sp_pwdp)) goto deny;
}
closelog();
xsetuser(up = xgetpwnam(name));
if (FLAG(m)||FLAG(p)) {
unsetenv("IFS");
setenv("PATH", _PATH_DEFPATH, 1);
} else reset_env(up, FLAG(l));
argv = argu = xmalloc(sizeof(char *)*(toys.optc + 4));
*(argv++) = TT.s ? TT.s : up->pw_shell;
loggit(LOG_NOTICE, "run %s", *argu);
if (FLAG(l)) *(argv++) = "-l";
if (FLAG(c)) {
*(argv++) = "-c";
*(argv++) = TT.c;
}
while ((*(argv++) = *(toys.optargs++)));
xexec(argu);
deny:
syslog(LOG_NOTICE, "No.");
puts("No.");
toys.exitval = 1;
}