/* See LICENSE file for license details. */

#define _XOPEN_SOURCE 500

#if HAVE_SHADOW_H

#include <shadow.h>

#endif

#include <ctype.h>

#include <pwd.h>

#include <stdarg.h>

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <unistd.h>

#include <sys/types.h>

#include <sys/ioctl.h>

#include <linux/vt.h>

#include <fcntl.h>

#include <errno.h>

#include <termios.h>

#include <X11/keysym.h>

#include <X11/Xlib.h>

#include <X11/Xutil.h>

#include <X11/extensions/dpms.h>

#if HAVE_BSD_AUTH

#include <login_cap.h>

#include <bsd_auth.h>

#endif

static void

die(const char *errstr, ...) {

va_list ap;

va_start(ap, errstr);

vfprintf(stderr, errstr, ap);

va_end(ap);

exit(EXIT_FAILURE);

}

#ifndef HAVE_BSD_AUTH

static const char *

get_password() { /* only run as root */

const char *rval;

struct passwd *pw;

if(geteuid() != 0)

die("sflock: cannot retrieve password entry (make sure to suid sflock)\n");

pw = getpwuid(getuid());

endpwent();

rval = pw->pw_passwd;

#if HAVE_SHADOW_H

{

struct spwd *sp;

sp = getspnam(getenv("USER"));

endspent();

rval = sp->sp_pwdp;

}

#endif

/* drop privileges temporarily */

if (setreuid(0, pw->pw_uid) == -1)

die("sflock: cannot drop privileges\n");

return rval;

}

#endif

int

main(int argc, char **argv) {

char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};

char buf[32], passwd[256], passdisp[256];

int num, screen, width, height, update, sleepmode, term, pid;

#ifndef HAVE_BSD_AUTH

const char *pws;

#endif

unsigned int len;

Bool running = True;

Cursor invisible;

Display *dpy;

KeySym ksym;

Pixmap pmap;

Window root, w;

XColor black, red, dummy;

XEvent ev;

XSetWindowAttributes wa;

XFontStruct* font;

GC gc;

XGCValues values;

// defaults

char* passchar = "*";

char* fontname = "-*-dejavu sans-bold-r-*-*-*-420-100-100-*-*-iso8859-1";

char* username = "";

int showline = 1;

int xshift = 0;

for (int i = 0; i < argc; i++) {

if (!strcmp(argv[i], "-c")) {

if (i + 1 < argc)

passchar = argv[i + 1];

else

die("error: no password character given.\n");

} else

if (!strcmp(argv[i], "-f")) {

if (i + 1 < argc)

fontname = argv[i + 1];

else

die("error: font not specified.\n");

}

else

if (!strcmp(argv[i], "-v"))

die("sflock-"VERSION", © 2015 Ben Ruijl\n");

else

if (!strcmp(argv[i], "-h"))

showline = 0;

else

if (!strcmp(argv[i], "-xshift"))

xshift = atoi(argv[i + 1]);

else

if (!strcmp(argv[i], "?"))

die("usage: sflock [-v] [-c passchars] [-f fontname] [-xshift horizontal shift]\n");

}

// fill with password characters

for (int i = 0; i < sizeof passdisp; i+= strlen(passchar))

for (int j = 0; j < strlen(passchar) && i + j < sizeof passdisp; j++)

passdisp[i + j] = passchar[j];

/* disable tty switching */

if ((term = open("/dev/console", O_RDWR)) == -1) {

perror("error opening console");

}

if ((ioctl(term, VT_LOCKSWITCH)) == -1) {

perror("error locking console");

}

/* deamonize */

pid = fork();

if (pid < 0)

die("Could not fork sflock.");

if (pid > 0)

exit(0); // exit parent

#ifndef HAVE_BSD_AUTH

pws = get_password();

username = getpwuid(geteuid())->pw_name;

#else

username = getlogin();

#endif

if(!(dpy = XOpenDisplay(0)))

die("sflock: cannot open dpy\n");

screen = DefaultScreen(dpy);

root = RootWindow(dpy, screen);

width = DisplayWidth(dpy, screen);

height = DisplayHeight(dpy, screen);

wa.override_redirect = 1;

wa.background_pixel = XBlackPixel(dpy, screen);

w = XCreateWindow(dpy, root, 0, 0, width, height,

0, DefaultDepth(dpy, screen), CopyFromParent,

DefaultVisual(dpy, screen), CWOverrideRedirect | CWBackPixel, &wa);

XAllocNamedColor(dpy, DefaultColormap(dpy, screen), "orange red", &red, &dummy);

XAllocNamedColor(dpy, DefaultColormap(dpy, screen), "black", &black, &dummy);

pmap = XCreateBitmapFromData(dpy, w, curs, 8, 8);

invisible = XCreatePixmapCursor(dpy, pmap, pmap, &black, &black, 0, 0);

XDefineCursor(dpy, w, invisible);

XMapRaised(dpy, w);

font = XLoadQueryFont(dpy, fontname);

if (font == 0) {

die("error: could not find font. Try using a full description.\n");

}

gc = XCreateGC(dpy, w, (unsigned long)0, &values);

XSetFont(dpy, gc, font->fid);

XSetForeground(dpy, gc, XWhitePixel(dpy, screen));

for(len = 1000; len; len--) {

if(XGrabPointer(dpy, root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,

GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)

break;

usleep(1000);

}

if((running = running && (len > 0))) {

for(len = 1000; len; len--) {

if(XGrabKeyboard(dpy, root, True, GrabModeAsync, GrabModeAsync, CurrentTime)

== GrabSuccess)

break;

usleep(1000);

}

running = (len > 0);

}

len = 0;

XSync(dpy, False);

update = True;

sleepmode = False;

/* main event loop */

while(running && !XNextEvent(dpy, &ev)) {

if (sleepmode) {

DPMSEnable(dpy);

DPMSForceLevel(dpy, DPMSModeOff);

XFlush(dpy);

}

if (update) {

int x, y, dir, ascent, descent;

XCharStruct overall;

XClearWindow(dpy, w);

XTextExtents (font, passdisp, len, &dir, &ascent, &descent, &overall);

x = (width - overall.width) / 2;

y = (height + ascent - descent) / 2;

XDrawString(dpy,w,gc, (width - XTextWidth(font, username, strlen(username))) / 2 + xshift, y - ascent - 20, username, strlen(username));

if (showline)

XDrawLine(dpy, w, gc, width * 3 / 8 + xshift, y - ascent - 10, width * 5 / 8 + xshift, y - ascent - 10);

XDrawString(dpy,w,gc, x + xshift, y, passdisp, len);

update = False;

}

if (ev.type == MotionNotify) {

sleepmode = False;

}

if(ev.type == KeyPress) {

sleepmode = False;

buf[0] = 0;

num = XLookupString(&ev.xkey, buf, sizeof buf, &ksym, 0);

if(IsKeypadKey(ksym)) {

if(ksym == XK_KP_Enter)

ksym = XK_Return;

else if(ksym >= XK_KP_0 && ksym <= XK_KP_9)

ksym = (ksym - XK_KP_0) + XK_0;

}

if(IsFunctionKey(ksym) || IsKeypadKey(ksym)

|| IsMiscFunctionKey(ksym) || IsPFKey(ksym)

|| IsPrivateKeypadKey(ksym))

continue;

switch(ksym) {

case XK_Return:

passwd[len] = 0;

#ifdef HAVE_BSD_AUTH

running = !auth_userokay(getlogin(), NULL, "auth-xlock", passwd);

#else

running = strcmp(crypt(passwd, pws), pws);

#endif

if (running != 0)

// change background on wrong password

XSetWindowBackground(dpy, w, red.pixel);

len = 0;

break;

case XK_Escape:

len = 0;

if (DPMSCapable(dpy)) {

sleepmode = True;

}

break;

case XK_BackSpace:

if(len)

--len;

break;

default:

if(num && !iscntrl((int) buf[0]) && (len + num < sizeof passwd)) {

memcpy(passwd + len, buf, num);

len += num;

}

break;

}

update = True; // show changes

}

}

/* free and unlock */

setreuid(geteuid(), 0);

if ((ioctl(term, VT_UNLOCKSWITCH)) == -1) {

perror("error unlocking console");

}

close(term);

setuid(getuid()); // drop rights permanently

XUngrabPointer(dpy, CurrentTime);

XFreePixmap(dpy, pmap);

XFreeFont(dpy, font);

XFreeGC(dpy, gc);

XDestroyWindow(dpy, w);

XCloseDisplay(dpy);

return 0;

}