clear passwords with explicit_bzero

[slock.git] / slock.c

diff --git a/slock.c b/slock.c
index d150009..a00fbb9 100644 (file)
--- a/slock.c
+++ b/slock.c
@@ -13,6 +13,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <string.h>
 #include <unistd.h>
 #include <sys/types.h>

+#include <X11/extensions/Xrandr.h>

 #include <X11/keysym.h>
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 #include <X11/keysym.h>
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>


@@ -22,54 +23,93 @@
 #include <bsd_auth.h>
 #endif
 
 #include <bsd_auth.h>
 #endif
 

-struct st_lock {
+#include "util.h"
+
+enum {
+       INIT,
+       INPUT,
+       FAILED,
+       NUMCOLS
+};
+
+#include "config.h"
+
+typedef struct {

        int screen;
        int screen;

-       Window root, w;
+       Window root, win;

        Pixmap pmap;
        Pixmap pmap;

-};
+       unsigned long colors[NUMCOLS];
+} Lock;

 
 

-extern const char *__progname;
+static Lock **locks;
+static int nscreens;
+static Bool running = True;
+static Bool failure = False;
+static Bool rr;
+static int rrevbase;
+static int rrerrbase;

 
 static void
 
 static void

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

        va_list ap;
 
        va_list ap;
 

-       fprintf(stderr, "%s: ", __progname);
+       fputs("slock: ", stderr);

        va_start(ap, errstr);
        vfprintf(stderr, errstr, ap);
        va_end(ap);
        va_start(ap, errstr);
        vfprintf(stderr, errstr, ap);
        va_end(ap);

-       fprintf(stderr, "\n");
-       fflush(stderr);
+       exit(1);
+}

 
 

-       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", (sizeof("-1000\n") - 1)) !=
+           (sizeof("-1000\n") - 1) || close(fd) != 0) {
+               die("can't tame the oom-killer. is suid or sgid set?\n");
+       }

 }
 }

+#endif

 
 #ifndef HAVE_BSD_AUTH
 
 #ifndef HAVE_BSD_AUTH

+/* only run as root */

 static const char *
 static const char *

-getpw(void) { /* only run as root */
+getpw(void)
+{

        const char *rval;
        struct passwd *pw;
 
        const char *rval;
        struct passwd *pw;
 

-       pw = getpwuid(getuid());
-       if(!pw)
-               die("cannot retrieve password entry (make sure to suid or sgid slock)");
-       endpwent();
-       rval =  pw->pw_passwd;
+       errno = 0;
+       if (!(pw = getpwuid(getuid()))) {
+               if (errno)
+                       die("getpwuid: %s\n", strerror(errno));
+               else
+                       die("cannot retrieve password entry\n");
+       }
+       rval = pw->pw_passwd;

 
 #if HAVE_SHADOW_H
 
 #if HAVE_SHADOW_H

-       {
+       if (rval[0] == 'x' && rval[1] == '\0') {

                struct spwd *sp;
                struct spwd *sp;

-               sp = getspnam(getenv("USER"));
-               if(!sp)
-                       die("slock: cannot retrieve shadow entry (make sure to suid or sgid slock)\n");
-               endspent();
+               if (!(sp = getspnam(getenv("USER"))))
+                       die("cannot retrieve shadow entry (make sure to suid or sgid slock)\n");

                rval = sp->sp_pwdp;
        }
 #endif
 
        /* drop privileges */
                rval = sp->sp_pwdp;
        }
 #endif
 
        /* drop privileges */

-       if(setgid(pw->pw_gid) < 0 || setuid(pw->pw_uid) < 0)
-               die("cannot drop privileges");
+       if (geteuid() == 0 &&
+           ((getegid() != pw->pw_gid && setgid(pw->pw_gid) < 0) || setuid(pw->pw_uid) < 0))
+               die("cannot drop privileges\n");

        return rval;
 }
 #endif
        return rval;
 }
 #endif


@@ -82,12 +122,11 @@ readpw(Display *dpy, const char *pws)
 #endif
 {
        char buf[32], passwd[256];
 #endif
 {
        char buf[32], passwd[256];

-       int num;
-
-       unsigned int len;
-       Bool running = True;
+       int num, screen;
+       unsigned int len, color;

        KeySym ksym;
        XEvent ev;
        KeySym ksym;
        XEvent ev;

+       static int oldc = INIT;

 
        len = 0;
        running = True;
 
        len = 0;
        running = True;


@@ -96,128 +135,153 @@ readpw(Display *dpy, const char *pws)
         * 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. */
         * 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(ev.type == KeyPress) {
-                       buf[0] = 0;
-                       num = XLookupString(&ev.xkey, buf, sizeof buf, &ksym, 0);
-                       if(IsKeypadKey(ksym)) {
-                               if(ksym == XK_KP_Enter)
+       while (running && !XNextEvent(dpy, &ev)) {
+               if (ev.type == KeyPress) {
+                       explicit_bzero(&buf, sizeof(buf));
+                       num = XLookupString(&ev.xkey, buf, sizeof(buf), &ksym, 0);
+                       if (IsKeypadKey(ksym)) {
+                               if (ksym == XK_KP_Enter)

                                        ksym = XK_Return;
                                        ksym = XK_Return;

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

                                        ksym = (ksym - XK_KP_0) + XK_0;
                        }
                                        ksym = (ksym - XK_KP_0) + XK_0;
                        }

-                       if(IsFunctionKey(ksym) || IsKeypadKey(ksym)
-                                       || IsMiscFunctionKey(ksym) || IsPFKey(ksym)
-                                       || IsPrivateKeypadKey(ksym))
+                       if (IsFunctionKey(ksym) ||
+                           IsKeypadKey(ksym) ||
+                           IsMiscFunctionKey(ksym) ||
+                           IsPFKey(ksym) ||
+                           IsPrivateKeypadKey(ksym))

                                continue;
                                continue;

-                       switch(ksym) {
+                       switch (ksym) {

                        case XK_Return:
                                passwd[len] = 0;
 #ifdef HAVE_BSD_AUTH
                                running = !auth_userokay(getlogin(), NULL, "auth-xlock", passwd);
 #else
                        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);
+                               running = !!strcmp(crypt(passwd, pws), pws);

 #endif
 #endif

-                               if (running != 0)
+                               if (running) {

                                        XBell(dpy, 100);
                                        XBell(dpy, 100);

+                                       failure = True;
+                               }
+                               explicit_bzero(&passwd, sizeof(passwd));

                                len = 0;
                                break;
                        case XK_Escape:
                                len = 0;
                                break;
                        case XK_Escape:

+                               explicit_bzero(&passwd, sizeof(passwd));

                                len = 0;
                                break;
                        case XK_BackSpace:
                                len = 0;
                                break;
                        case XK_BackSpace:

-                               if(len)
-                                       --len;
+                               if (len)
+                                       passwd[len--] = 0;

                                break;
                        default:
                                break;
                        default:

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

                                        memcpy(passwd + len, buf, num);
                                        len += num;
                                }
                                break;
                        }
                                        memcpy(passwd + len, buf, num);
                                        len += num;
                                }
                                break;
                        }

-               }
+                       color = len ? INPUT : (failure || failonclear ? FAILED : INIT);
+                       if (running && oldc != color) {
+                               for (screen = 0; screen < nscreens; screen++) {
+                                       XSetWindowBackground(dpy, locks[screen]->win, locks[screen]->colors[color]);
+                                       XClearWindow(dpy, locks[screen]->win);
+                               }
+                               oldc = color;
+                       }
+               } else if (rr && ev.type == rrevbase + RRScreenChangeNotify) {
+                       XRRScreenChangeNotifyEvent *rre = (XRRScreenChangeNotifyEvent*)&ev;
+                       for (screen = 0; screen < nscreens; screen++) {
+                               if (locks[screen]->win == rre->window) {
+                                       XResizeWindow(dpy, locks[screen]->win, rre->width, rre->height);
+                                       XClearWindow(dpy, locks[screen]->win);
+                               }
+                       }
+               } else for (screen = 0; screen < nscreens; screen++)
+                       XRaiseWindow(dpy, locks[screen]->win);

        }
 }
 
 static void
        }
 }
 
 static void

-unlockscreen(Display *dpy, struct st_lock *lock) {
-       if (dpy == NULL || lock == NULL)
+unlockscreen(Display *dpy, Lock *lock)
+{
+       if(dpy == NULL || lock == NULL)

                return;
 
        XUngrabPointer(dpy, CurrentTime);
                return;
 
        XUngrabPointer(dpy, CurrentTime);

+       XFreeColors(dpy, DefaultColormap(dpy, lock->screen), lock->colors, NUMCOLS, 0);

        XFreePixmap(dpy, lock->pmap);
        XFreePixmap(dpy, lock->pmap);

-       XDestroyWindow(dpy, lock->w);
+       XDestroyWindow(dpy, lock->win);

 
        free(lock);
 }
 
 
        free(lock);
 }
 

-static struct st_lock *
-lockscreen(Display *dpy, int screen) {
+static Lock *
+lockscreen(Display *dpy, int screen)
+{

        char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
        unsigned int len;
        char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
        unsigned int len;

-       struct st_lock *lock;
-       Bool running = True;
-       XColor black, dummy;
+       int i;
+       Lock *lock;
+       XColor color, dummy;

        XSetWindowAttributes wa;
        Cursor invisible;
 
        XSetWindowAttributes wa;
        Cursor invisible;
 

-       if (dpy == NULL || screen < 0)
-               return NULL;
-
-       lock = malloc(sizeof(struct st_lock));
-       if (lock == NULL)
+       if (!running || dpy == NULL || screen < 0 || !(lock = malloc(sizeof(Lock))))

                return NULL;
 
        lock->screen = screen;
                return NULL;
 
        lock->screen = screen;

-

        lock->root = RootWindow(dpy, lock->screen);
 
        lock->root = RootWindow(dpy, lock->screen);
 

+       for (i = 0; i < NUMCOLS; i++) {
+               XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), colorname[i], &color, &dummy);
+               lock->colors[i] = color.pixel;
+       }
+

        /* init */
        wa.override_redirect = 1;
        /* init */
        wa.override_redirect = 1;

-       wa.background_pixel = BlackPixel(dpy, lock->screen);
-       lock->w = XCreateWindow(dpy, lock->root, 0, 0, DisplayWidth(dpy, lock->screen), DisplayHeight(dpy, lock->screen),
-                       0, DefaultDepth(dpy, lock->screen), CopyFromParent,
-                       DefaultVisual(dpy, lock->screen), CWOverrideRedirect | CWBackPixel, &wa);
-       XAllocNamedColor(dpy, DefaultColormap(dpy, lock->screen), "black", &black, &dummy);
-       lock->pmap = XCreateBitmapFromData(dpy, lock->w, curs, 8, 8);
-       invisible = XCreatePixmapCursor(dpy, lock->pmap, lock->pmap, &black, &black, 0, 0);
-       XDefineCursor(dpy, lock->w, invisible);
-       XMapRaised(dpy, lock->w);
-       for(len = 1000; len; len--) {
-               if(XGrabPointer(dpy, lock->root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
-                       GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)
+       wa.background_pixel = lock->colors[INIT];
+       lock->win = XCreateWindow(dpy, lock->root, 0, 0, DisplayWidth(dpy, lock->screen), DisplayHeight(dpy, lock->screen),
+                                 0, DefaultDepth(dpy, lock->screen), CopyFromParent,
+                                 DefaultVisual(dpy, lock->screen), CWOverrideRedirect | CWBackPixel, &wa);
+       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);
+       XMapRaised(dpy, lock->win);
+       if (rr)
+               XRRSelectInput(dpy, lock->win, RRScreenChangeNotifyMask);
+
+       /* Try to grab mouse pointer *and* keyboard, else fail the lock */
+       for (len = 1000; len; len--) {
+               if (XGrabPointer(dpy, lock->root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
+                   GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)

                        break;
                usleep(1000);
        }
                        break;
                usleep(1000);
        }

-       if((running = running && (len > 0))) {
-               for(len = 1000; len; len--) {
-                       if(XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync, CurrentTime)
-                               == GrabSuccess)
-                               break;
+       if (!len) {
+               fprintf(stderr, "slock: unable to grab mouse pointer for screen %d\n", screen);
+       } else {
+               for (len = 1000; len; len--) {
+                       if (XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync, CurrentTime) == GrabSuccess) {
+                               /* everything fine, we grabbed both inputs */
+                               XSelectInput(dpy, lock->root, SubstructureNotifyMask);
+                               return lock;
+                       }

                        usleep(1000);
                }
                        usleep(1000);
                }

-               running = (len > 0);
-       }
-
-       if (!running) {
-               unlockscreen(dpy, lock);
-               lock = NULL;
+               fprintf(stderr, "slock: unable to grab keyboard for screen %d\n", screen);

        }
        }

-
-       return lock;
+       /* grabbing one of the inputs failed */
+       running = 0;
+       unlockscreen(dpy, lock);
+       return NULL;

 }
 
 static void
 }
 
 static void

-usage(void) {
-       fprintf(stderr, "usage: %s -v", __progname);
-       exit(EXIT_FAILURE);
-}
-
-static int
-xerrordummy(Display *dpy, XErrorEvent *ee) {
-       return 0;
+usage(void)
+{
+       fprintf(stderr, "usage: slock [-v|POST_LOCK_CMD]\n");
+       exit(1);

 }
 
 int
 }
 
 int


@@ -226,36 +290,53 @@ main(int argc, char **argv) {
        const char *pws;
 #endif
        Display *dpy;
        const char *pws;
 #endif
        Display *dpy;

-       int nscreens, screen;
+       int screen;

 
 

-       struct st_lock **locks;
+       if ((argc >= 2) && !strcmp("-v", argv[1]))
+               die("version %s, © 2006-2016 slock engineers\n", VERSION);

 
 

-       if((argc == 2) && !strcmp("-v", argv[1]))
-               die("slock-%s, © 2006-2012 Anselm R Garbe", VERSION);
-       else if(argc != 1)
+       /* treat first argument starting with a '-' as option */
+       if ((argc >= 2) && argv[1][0] == '-')

                usage();
 
                usage();
 

-       if(!getpwuid(getuid()))
-               die("no passwd entry for you");
+#ifdef __linux__
+       dontkillme();
+#endif
+
+       if (!getpwuid(getuid()))
+               die("no passwd entry for you\n");

 
 #ifndef HAVE_BSD_AUTH
        pws = getpw();
 #endif
 
 
 #ifndef HAVE_BSD_AUTH
        pws = getpw();
 #endif
 

-       if(!(dpy = XOpenDisplay(0)))
-               die("cannot open display");
-       /* prevent default error handler to take over */
-       XSetErrorHandler(xerrordummy);
+       if (!(dpy = XOpenDisplay(0)))
+               die("cannot open display\n");
+       rr = XRRQueryExtension(dpy, &rrevbase, &rrerrbase);

        /* Get the number of screens in display "dpy" and blank them all. */
        nscreens = ScreenCount(dpy);
        /* Get the number of screens in display "dpy" and blank them all. */
        nscreens = ScreenCount(dpy);

-       locks = malloc(sizeof(struct st_lock *) * nscreens);
-       if (locks == NULL)
-               die("malloc: %s", strerror(errno));
+       if (!(locks = malloc(sizeof(Lock*) * nscreens)))
+               die("Out of memory.\n");
+       int nlocks = 0;
+       for (screen = 0; screen < nscreens; screen++) {
+               if ((locks[screen] = lockscreen(dpy, screen)) != NULL)
+                       nlocks++;
+       }
+       XSync(dpy, False);

 
 

-       for (screen = 0; screen < nscreens; screen++)
-               locks[screen] = lockscreen(dpy, screen);
+       /* Did we actually manage to lock something? */
+       if (nlocks == 0) { /* nothing to protect */
+               free(locks);
+               XCloseDisplay(dpy);
+               return 1;
+       }

 
 

-       XSync(dpy, False);
+       if (argc >= 2 && fork() == 0) {
+               if (dpy)
+                       close(ConnectionNumber(dpy));
+               execvp(argv[1], argv+1);
+               die("execvp %s failed: %s\n", argv[1], strerror(errno));
+       }

 
        /* Everything is now blank. Now wait for the correct password. */
 #ifdef HAVE_BSD_AUTH
 
        /* Everything is now blank. Now wait for the correct password. */
 #ifdef HAVE_BSD_AUTH


@@ -269,7 +350,6 @@ main(int argc, char **argv) {
                unlockscreen(dpy, locks[screen]);
 
        free(locks);
                unlockscreen(dpy, locks[screen]);
 
        free(locks);

-

        XCloseDisplay(dpy);
 
        return 0;
        XCloseDisplay(dpy);
 
        return 0;