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slock/slock.c
Austen Adler b88329b66d
Fix spelling error
2016-08-21 01:54:32 -04:00

781 lines
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/* See LICENSE file for license details. */
#define _XOPEN_SOURCE 500
#if HAVE_SHADOW_H
#include <shadow.h>
#endif
#include <ctype.h>
#include <errno.h>
#include <pwd.h>
#include <stdarg.h>
#include <stdlib.h>
#define _GNU_SOURCE
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <X11/keysym.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/extensions/dpms.h>
#include <X11/Xatom.h>
#if HAVE_BSD_AUTH
#include <login_cap.h>
#include <bsd_auth.h>
#endif
#define CMD_LENGTH (500 * sizeof(char))
#define POWEROFF 0
#define TWILIO_SEND 0
#define WEBCAM_SHOT 0
#define IMGUR_UPLOAD 0
#define PLAY_AUDIO 0
#define TRANSPARENT 0
#if IMGUR_UPLOAD
#include "imgur.h"
#endif
#if TWILIO_SEND
#include "twilio.h"
#endif
typedef struct {
char *link;
char *deletehash;
} imgur_data;
char *g_pw = NULL;
int lock_tries = 0;
typedef struct {
int screen;
Window root, win;
Pixmap pmap;
unsigned long colors[2];
} Lock;
static Lock **locks;
static int nscreens;
static Bool running = True;
static void
die(const char *errstr, ...) {
va_list ap;
va_start(ap, errstr);
vfprintf(stderr, errstr, ap);
va_end(ap);
exit(EXIT_FAILURE);
}
#ifdef __linux__
#include <fcntl.h>
static void
dontkillme(void) {
int fd;
fd = open("/proc/self/oom_score_adj", O_WRONLY);
if (fd < 0 && errno == ENOENT)
return;
if (fd < 0 || write(fd, "-1000\n", 6) != 6 || close(fd) != 0)
fprintf(stderr, "cannot disable the out-of-memory killer for this process\n");
}
#endif
#ifndef HAVE_BSD_AUTH
static const char *
getpw(void) { /* only run as root */
const char *rval;
struct passwd *pw;
if(g_pw)
return g_pw;
errno = 0;
pw = getpwuid(getuid());
if (!pw) {
if (errno)
die("slock: getpwuid: %s\n", strerror(errno));
else
die("slock: cannot retrieve password entry (make sure to suid or sgid slock)\n");
}
endpwent();
rval = pw->pw_passwd;
#if HAVE_SHADOW_H
if (rval[0] == 'x' && rval[1] == '\0') {
struct spwd *sp;
sp = getspnam(getenv("USER"));
if(!sp)
die("slock: cannot retrieve shadow entry (make sure to suid or sgid slock)\n");
endspent();
rval = sp->sp_pwdp;
}
#endif
/* drop privileges */
if (geteuid() == 0
&& ((getegid() != pw->pw_gid && setgid(pw->pw_gid) < 0) || setuid(pw->pw_uid) < 0))
die("slock: cannot drop privileges\n");
return rval;
}
#endif
static char *
read_tfile(char *name) {
FILE *f = fopen(name, "r");
struct stat s;
if (stat(name, &s) == -1) goto error;
char *buf = malloc(s.st_size);
if (buf == NULL) goto error;
fread(buf, 1, s.st_size, f);
fclose(f);
int i = 0;
while (buf[i]) {
if (buf[i] == '\r' || buf[i] == '\n') {
buf[i] = '\0';
break;
}
i++;
}
return buf;
error:
fprintf(stderr, "Could not open: %s.\n", name);
return NULL;
}
// Disable alt+sysrq and crtl+alt+backspace - keeps the
// attacker from alt+sysrq+k'ing our process
static void
disable_kill(void) {
#if POWEROFF
// Needs sudo privileges - alter your /etc/sudoers file:
// [username] [hostname] =NOPASSWD: /usr/bin/tee /proc/sys/kernel/sysrq
system("echo 0 | sudo tee /proc/sys/kernel/sysrq > /dev/null &");
// Disable ctrl+alt+backspace
system("setxkbmap -option &");
#else
return;
#endif
}
// Poweroff if we're in danger.
static void
poweroff(void) {
#if POWEROFF
// Needs sudo privileges - alter your /etc/sudoers file:
// systemd: [username] [hostname] =NOPASSWD: /usr/bin/systemctl poweroff
// sysvinit: [username] [hostname] =NOPASSWD: /usr/bin/shutdown -h now
char *args[] = { "sudo", "shutdown", "-h", "now", NULL };
execvp(args[0], args);
fprintf(stderr, "Error: cannot shutdown. Check your /etc/sudoers file.\n");
// Needs sudo privileges - alter your /etc/sudoers file:
// [username] [hostname] =NOPASSWD: /usr/bin/tee /proc/sys/kernel/sysrq,/usr/bin/tee /proc/sysrq-trigger
// system("echo 1 | sudo tee /proc/sys/kernel/sysrq > /dev/null");
// system("echo o | sudo tee /proc/sysrq-trigger > /dev/null");
#else
return;
#endif
}
// Take a screenshot of whoever is at the keyboard.
static int
webcam_shot(int async) {
#if WEBCAM_SHOT
char *cmd = (char *)malloc(CMD_LENGTH);
int r = snprintf(cmd, CMD_LENGTH,
"ffmpeg -y -loglevel quiet -f video4linux2 -i /dev/video0"
" -frames:v 1 -f image2 %s/slock.jpg%s",
getenv("HOME"), async ? " &" : "");
if (r > 0) {
system(cmd);
r = 0;
} else {
r = -1;
}
free(cmd);
return r;
#else
return 0;
#endif
}
static int
twilio_send(const char *msg, imgur_data *idata, int async) {
#if TWILIO_SEND
char *cmd = (char *)malloc(CMD_LENGTH);
// Send the SMS/MMS via Twilio
int r = snprintf(cmd, CMD_LENGTH,
"curl -s -A '' -X POST https://api.twilio.com/2010-04-01/Accounts/"
TWILIO_ACCOUNT "/SMS/Messages.json"
" -u " TWILIO_AUTH
" --data-urlencode 'From=" TWILIO_FROM "'"
" --data-urlencode 'To=" TWILIO_TO "'"
" --data-urlencode 'Body=%s'"
" --data-urlencode 'MediaUrl=%s' > /dev/null"
"%s", msg, idata ? idata->link : "", async ? " &" : "");
if (r > 0) {
system(cmd);
r = 0;
} else {
r = -1;
}
free(cmd);
return r;
#else
return 0;
#endif
}
static imgur_data *
imgur_upload(void) {
#if IMGUR_UPLOAD
char *buf = (char *)malloc(CMD_LENGTH);
imgur_data *idata = (imgur_data *)malloc(sizeof(imgur_data));
memset(idata, 0, sizeof(imgur_data));
int r;
// Upload the imgur image:
r = snprintf(buf, CMD_LENGTH,
"curl -s -A '' -X POST"
" -H 'Authorization: Client-ID " IMGUR_CLIENT "'"
" -F 'image=@%s/slock.jpg'"
" 'https://api.imgur.com/3/image' > %s/slock_imgur.curl",
getenv("HOME"), getenv("HOME"));
if (r > 0) {
system(buf);
r = 0;
} else {
r = -1;
}
if (r == -1) return NULL;
// Get the link:
r = snprintf(buf, CMD_LENGTH,
"cat %s/slock_imgur.curl"
" | grep -o '\"link\":\"[^\"]\\+'"
" | sed 's/\\\\//g'"
" | grep -o '[^\"]\\+$'"
" > %s/slock_imgur.link",
getenv("HOME"), getenv("HOME"));
if (r > 0) {
system(buf);
r = 0;
} else {
r = -1;
}
if (r == -1) return NULL;
// Get the deletehash:
r = snprintf(buf, CMD_LENGTH,
"cat %s/slock_imgur.curl"
" | grep -o '\"deletehash\":\"[^\"]\\+'"
" | grep -o '[^\"]\\+$'"
" > %s/slock_imgur.deletehash",
getenv("HOME"), getenv("HOME"));
if (r > 0) {
system(buf);
r = 0;
} else {
r = -1;
}
if (r == -1) return NULL;
r = snprintf(buf, CMD_LENGTH, "%s/slock_imgur.curl", getenv("HOME"));
if (r > 0) {
unlink(buf);
}
r = snprintf(buf, CMD_LENGTH, "%s/slock_imgur.link", getenv("HOME"));
if (r > 0) {
idata->link = read_tfile(buf);
unlink(buf);
}
r = snprintf(buf, CMD_LENGTH, "%s/slock_imgur.deletehash", getenv("HOME"));
if (r > 0) {
idata->deletehash = read_tfile(buf);
unlink(buf);
}
free(buf);
if (idata->link == NULL
|| !strlen(idata->link)
|| idata->deletehash == NULL
|| !strlen(idata->deletehash)) {
return NULL;
}
return idata;
#else
return NULL;
#endif
}
static int
imgur_delete(imgur_data *idata) {
#if IMGUR_UPLOAD
char *cmd = (char *)malloc(CMD_LENGTH);
// Delete the imgur image:
int r = snprintf(cmd, CMD_LENGTH,
"curl -s -A '' -X DELETE"
" -H 'Authorization: Client-ID " IMGUR_CLIENT "'"
" 'https://api.imgur.com/3/image/%s'", idata->deletehash);
// Wait for Twilio to do its request:
sleep(5);
if (r > 0) {
system(cmd);
r = 0;
} else {
r = -1;
}
free(cmd);
free(idata->link);
free(idata->deletehash);
free(idata);
return r;
#else
return 0;
#endif
}
static void
play_beep(int async) {
#if PLAY_AUDIO
char snd[255] = {0};
snprintf(snd, sizeof(snd), "aplay %s/slock/beep.wav 2> /dev/null%s",
getenv("HOME"), async ? " &" : "");
system(snd);
#else
return;
#endif
}
static void
play_alarm(int async) {
#if PLAY_AUDIO
char snd[255] = {0};
snprintf(snd, sizeof(snd), "aplay %s/slock/police.wav 2> /dev/null%s",
getenv("HOME"), async ? " &" : "");
system(snd);
#else
return;
#endif
}
static void
#ifdef HAVE_BSD_AUTH
readpw(Display *dpy)
#else
readpw(Display *dpy, const char *pws)
#endif
{
char buf[32], passwd[256];
int num, screen;
#if !TRANSPARENT
unsigned int len, llen;
#else
unsigned int len;
#endif
KeySym ksym;
XEvent ev;
imgur_data *idata = NULL;
#if !TRANSPARENT
len = llen = 0;
#else
len = 0;
#endif
running = True;
/* As "slock" stands for "Simple X display locker", the DPMS settings
* had been removed and you can set it with "xset" or some other
* utility. This way the user can easily set a customized DPMS
* timeout. */
while(running && !XNextEvent(dpy, &ev)) {
if(len == 0 && DPMSCapable(dpy)) {
DPMSEnable(dpy);
DPMSForceLevel(dpy, DPMSModeOff);
}
if(ev.type == KeyPress) {
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;
if(g_pw) {
running = !!strcmp(passwd, g_pw);
} else {
#ifdef HAVE_BSD_AUTH
running = !auth_userokay(getlogin(), NULL, "auth-xlock", passwd);
#else
running = !!strcmp(crypt(passwd, pws), pws);
#endif
}
if(running) {
XBell(dpy, 100);
lock_tries++;
// Poweroff if there are more than 5 bad attempts.
if(lock_tries > 5) {
// Disable alt+sysrq and crtl+alt+backspace
disable_kill();
// Take a webcam shot of whoever is tampering with our machine:
webcam_shot(0);
// Upload the image:
idata = imgur_upload();
// Send an SMS/MMS via twilio:
twilio_send("Bad screenlock password.", idata, 0);
// Delete the image from imgur:
imgur_delete(idata);
// Immediately poweroff:
poweroff();
// If we failed, simply resume:
len = 0;
break;
} else {
// Take a webcam shot of whoever is tampering with our machine:
webcam_shot(1);
// Send an SMS via twilio:
twilio_send("Bad screenlock password.", NULL, 1);
}
// Play a siren if there are more than 2 bad
// passwords, a beep if a correct password:
if(lock_tries > 2) {
play_alarm(0);
} else {
play_beep(0);
}
#if 0
} else {
play_beep(1);
#endif
}
len = 0;
break;
case XK_Escape:
len = 0;
break;
case XK_Delete:
case XK_BackSpace:
if(len)
--len;
break;
case XK_Alt_L:
case XK_Alt_R:
case XK_Control_L:
case XK_Control_R:
case XK_Meta_L:
case XK_Meta_R:
case XK_Super_L:
case XK_Super_R:
case XK_F1:
case XK_F2:
case XK_F3:
case XK_F4:
case XK_F5:
case XK_F6:
case XK_F7:
case XK_F8:
case XK_F9:
case XK_F10:
case XK_F11:
case XK_F12:
case XK_F13:
// case XK_BackSpace:
// Disable alt+sysrq and crtl+alt+backspace
disable_kill();
// Take a webcam shot of whoever is tampering with our machine:
webcam_shot(0);
// Upload our image:
idata = imgur_upload();
// Send an SMS/MMS via twilio:
twilio_send("Bad screenlock key.", idata, 0);
// Delete the image from imgur:
imgur_delete(idata);
// Immediately poweroff:
poweroff();
; // fall-through if we fail
default:
if(num && !iscntrl((int) buf[0]) && (len + num < sizeof passwd)) {
memcpy(passwd + len, buf, num);
len += num;
}
break;
}
#if !TRANSPARENT
if(llen == 0 && len != 0) {
for(screen = 0; screen < nscreens; screen++) {
XSetWindowBackground(dpy, locks[screen]->win, locks[screen]->colors[1]);
XClearWindow(dpy, locks[screen]->win);
}
} else if(llen != 0 && len == 0) {
for(screen = 0; screen < nscreens; screen++) {
XSetWindowBackground(dpy, locks[screen]->win, locks[screen]->colors[0]);
XClearWindow(dpy, locks[screen]->win);
}
}
llen = len;
#endif
}
else for(screen = 0; screen < nscreens; screen++)
XRaiseWindow(dpy, locks[screen]->win);
}
}
static void
unlockscreen(Display *dpy, Lock *lock) {
if(dpy == NULL || lock == NULL)
return;
XUngrabPointer(dpy, CurrentTime);
#if !TRANSPARENT
XFreeColors(dpy, DefaultColormap(dpy, lock->screen), lock->colors, 2, 0);
XFreePixmap(dpy, lock->pmap);
#endif
XDestroyWindow(dpy, lock->win);
free(lock);
}
static Lock *
lockscreen(Display *dpy, int screen) {
#if !TRANSPARENT
char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
#endif
unsigned int len;
Lock *lock;
#if !TRANSPARENT
XColor color, dummy;
#endif
XSetWindowAttributes wa;
#if !TRANSPARENT
Cursor invisible;
#endif
#if TRANSPARENT
XVisualInfo vi;
#endif
if(dpy == NULL || screen < 0)
return NULL;
lock = malloc(sizeof(Lock));
if(lock == NULL)
return NULL;
lock->screen = screen;
lock->root = RootWindow(dpy, lock->screen);
#if TRANSPARENT
XMatchVisualInfo(dpy, DefaultScreen(dpy), 32, TrueColor, &vi);
wa.colormap = XCreateColormap(dpy, DefaultRootWindow(dpy), vi.visual, AllocNone);
#endif
/* init */
wa.override_redirect = 1;
#if !TRANSPARENT
wa.background_pixel = BlackPixel(dpy, lock->screen);
#else
wa.border_pixel = 0;
wa.background_pixel = 0xaa000000;
#endif
lock->win = XCreateWindow(dpy, lock->root, 0, 0, DisplayWidth(dpy, lock->screen), DisplayHeight(dpy, lock->screen),
#if !TRANSPARENT
0, DefaultDepth(dpy, lock->screen), CopyFromParent,
DefaultVisual(dpy, lock->screen), CWOverrideRedirect | CWBackPixel, &wa);
#else
0, vi.depth, CopyFromParent,
vi.visual, CWOverrideRedirect | CWBackPixel | CWColormap | CWBorderPixel, &wa);
#endif
Atom name_atom = XA_WM_NAME;
XTextProperty name_prop = { "slock", name_atom, 8, 5 };
XSetWMName(dpy, lock->win, &name_prop);
// Atom name_ewmh_atom = XInternAtom(dpy, "_NET_WM_NAME", False);
// XTextProperty name_ewmh_prop = { "slock", name_ewmh_atom, 8, 5 };
// XSetTextProperty(dpy, lock->win, &name_ewmh_prop, name_ewmh_atom);
// XSetWMName(dpy, lock->win, &name_ewmh_prop);
XClassHint *hint = XAllocClassHint();
if (hint) {
hint->res_name = "slock";
hint->res_class = "slock";
XSetClassHint(dpy, lock->win, hint);
XFree(hint);
}
#if !TRANSPARENT
XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), COLOR2, &color, &dummy);
lock->colors[1] = color.pixel;
XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), COLOR1, &color, &dummy);
lock->colors[0] = color.pixel;
lock->pmap = XCreateBitmapFromData(dpy, lock->win, curs, 8, 8);
invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap, &color, &color, 0, 0);
XDefineCursor(dpy, lock->win, invisible);
#endif
XMapRaised(dpy, lock->win);
for(len = 1000; len; len--) {
if(XGrabPointer(dpy, lock->root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
#if !TRANSPARENT
GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)
#else
GrabModeAsync, GrabModeAsync, None, None, CurrentTime) == GrabSuccess)
#endif
break;
usleep(1000);
}
if(running && (len > 0)) {
for(len = 1000; len; len--) {
if(XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync, CurrentTime)
== GrabSuccess)
break;
usleep(1000);
}
}
running &= (len > 0);
if(!running) {
unlockscreen(dpy, lock);
lock = NULL;
}
else
XSelectInput(dpy, lock->root, SubstructureNotifyMask);
return lock;
}
static void
usage(void) {
fprintf(stderr, "usage: slock [-v]\n");
exit(EXIT_FAILURE);
}
int
main(int argc, char **argv) {
#ifndef HAVE_BSD_AUTH
const char *pws;
#endif
Display *dpy;
int screen;
#ifdef SLOCK_QUIET
freopen("/dev/null", "a", stdout);
freopen("/dev/null", "a", stderr);
#endif
char buf[255] = {0};
snprintf(buf, sizeof(buf), "%s/.slock_passwd", getenv("HOME"));
g_pw = read_tfile(buf);
if((argc >= 2) && !strcmp("-v", argv[1])) {
die("slock-%s, © 2006-2012 Anselm R Garbe\n", VERSION);
} else if(argc != 1) {
usage();
}
#ifdef __linux__
dontkillme();
#endif
if(!g_pw && !getpwuid(getuid()))
die("slock: no passwd entry for you\n");
#ifndef HAVE_BSD_AUTH
pws = getpw();
if (strlen(pws) < 2) {
die("This user has no password set.\n");
}
#endif
if(!(dpy = XOpenDisplay(0)))
die("slock: cannot open display\n");
/* Get the number of screens in display "dpy" and blank them all. */
nscreens = ScreenCount(dpy);
locks = malloc(sizeof(Lock *) * nscreens);
if(locks == NULL)
die("slock: malloc: %s\n", strerror(errno));
int nlocks = 0;
for(screen = 0; screen < nscreens; screen++) {
if ( (locks[screen] = lockscreen(dpy, screen)) != NULL)
nlocks++;
}
XSync(dpy, False);
/* Did we actually manage to lock something? */
if (nlocks == 0) { // nothing to protect
free(locks);
XCloseDisplay(dpy);
return 1;
}
/* Everything is now blank. Now wait for the correct password. */
#ifdef HAVE_BSD_AUTH
readpw(dpy);
#else
readpw(dpy, pws);
#endif
/* Password ok, unlock everything and quit. */
for(screen = 0; screen < nscreens; screen++)
unlockscreen(dpy, locks[screen]);
free(locks);
XCloseDisplay(dpy);
return 0;
}
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