ubase/su.c
2014-06-02 17:15:41 +01:00

182 lines
3.8 KiB
C

/* See LICENSE file for copyright and license details. */
#define _XOPEN_SOURCE
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#include <pwd.h>
#include <grp.h>
#include <shadow.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <time.h>
#include "config.h"
#include "util.h"
extern char **environ;
static const char *randreply(void);
static char *msetenv(const char *, const char *);
static void dologin(struct passwd *);
static void
usage(void)
{
eprintf("usage: %s [-lp] [user]\n", argv0);
}
static int lflag = 0;
static int pflag = 0;
int
main(int argc, char *argv[])
{
char *usr = "root", *pass, *cryptpass;
char * const *newargv;
struct spwd *spw;
struct passwd *pw;
uid_t uid;
ARGBEGIN {
case 'l':
lflag = 1;
break;
case 'p':
pflag = 1;
break;
default:
usage();
} ARGEND;
if (argc < 1)
;
else if (argc == 1)
usr = argv[0];
else
usage();
srand(time(NULL));
errno = 0;
spw = getspnam(usr);
if (errno)
eprintf("getspnam: %s:", usr);
else if (!spw)
eprintf("who are you?\n");
switch (spw->sp_pwdp[0]) {
case '!':
case '*':
eprintf("denied\n");
}
uid = getuid();
if (uid) {
pass = getpass("Password: ");
if (!pass)
eprintf("getpass:");
cryptpass = crypt(pass, spw->sp_pwdp);
explicit_bzero(pass, strlen(pass));
if (!cryptpass)
eprintf("crypt:");
if (strcmp(cryptpass, spw->sp_pwdp) != 0)
eprintf(randreply());
explicit_bzero(cryptpass, strlen(cryptpass));
explicit_bzero(spw, sizeof *spw);
}
errno = 0;
pw = getpwnam(usr);
if (errno)
eprintf("getpwnam: %s", usr);
else if (!pw)
eprintf("who are you?\n");
if (initgroups(usr, pw->pw_gid) < 0)
eprintf("initgroups:");
if (setgid(pw->pw_gid) < 0)
eprintf("setgid:");
if (setuid(pw->pw_uid) < 0)
eprintf("setuid:");
if (lflag) {
dologin(pw);
} else {
newargv = (char *const[]){pw->pw_shell, NULL};
if (!pflag) {
setenv("HOME", pw->pw_dir, 1);
setenv("SHELL", pw->pw_shell, 1);
if (strcmp(pw->pw_name, "root") != 0) {
setenv("USER", pw->pw_name, 1);
setenv("LOGNAME", pw->pw_name, 1);
}
}
if (strcmp(pw->pw_name, "root") == 0)
setenv("PATH", ENV_SUPATH, 1);
else
setenv("PATH", ENV_PATH, 1);
execve(pflag ? getenv("SHELL") : pw->pw_shell,
newargv, environ);
}
return (errno == ENOENT) ? 127 : 126;
}
static const char *
randreply(void)
{
static const char *replies[] = {
"Time flies like an arrow, fruit flies like a banana.\n",
"Denied.\n",
"You type like a dairy farmer.\n",
"CChheecckk yyoouurr dduupplleexx sswwiittcchh..\n",
"I met a girl with 12 nipples, it sounds weird dozen tit?\n",
"Here I am, brain the size of a planet and they ask me to keep hashing rubbish.\n",
"Clones are people two.\n",
"Your mom is an interesting su response.\n",
"no.\n",
"Your mom forgot to null-terminate???B?33??Abort (core dumped)\n",
"A fool-proof method for sculpting an elephant: first, get a huge block of marble; then you chip away everything that doesn't look like an elephant.\n",
"Bloating .data for fun and profit.\n",
};
return replies[rand() % LEN(replies)];
}
static char *
msetenv(const char *name, const char *value)
{
char *buf;
size_t sz;
sz = strlen(name) + strlen(value) + 2;
buf = emalloc(sz);
snprintf(buf, sz, "%s=%s", name, value);
return buf;
}
static void
dologin(struct passwd *pw)
{
char shbuf[strlen(pw->pw_shell) + 1];
char * const *newargv;
char * const *newenv;
strcpy(shbuf, pw->pw_shell);
newargv = (char *const[]){shbuf, NULL};
newenv = (char *const[]){
msetenv("HOME", pw->pw_dir),
msetenv("SHELL", pw->pw_shell),
msetenv("USER", pw->pw_name),
msetenv("LOGNAME", pw->pw_name),
msetenv("TERM", getenv("TERM")),
msetenv("PATH",
strcmp(pw->pw_name, "root") == 0 ?
ENV_SUPATH : ENV_PATH),
NULL
};
if (chdir(pw->pw_dir) < 0)
eprintf("chdir %s:", pw->pw_dir);
execve(pw->pw_shell, newargv, newenv);
}