fix CVE-2016-6866

[slock.git] / slock.c

diff --git a/slock.c b/slock.c
index 210d5c8..8ed59ca 100644 (file)
--- a/slock.c
+++ b/slock.c
@@ -123,7 +123,7 @@ readpw(Display *dpy)
 readpw(Display *dpy, const char *pws)
 #endif
 {
-       char buf[32], passwd[256];
+       char buf[32], passwd[256], *encrypted;
        int num, screen;
        unsigned int len, color;
        KeySym ksym;
@@ -157,9 +157,13 @@ readpw(Display *dpy, const char *pws)
                        case XK_Return:
                                passwd[len] = 0;
 #ifdef HAVE_BSD_AUTH
-                               running = !auth_userokay(getlogin(), NULL, "auth-xlock", passwd);
+                               running = !auth_userokay(getlogin(), NULL, "auth-slock", passwd);
 #else
-                               running = !!strcmp(crypt(passwd, pws), pws);
+                               errno = 0;
+                               if (!(encrypted = crypt(passwd, pws)))
+                                       fprintf(stderr, "slock: crypt: %s\n", strerror(errno));
+                               else
+                                       running = !!strcmp(encrypted, pws);
 #endif
                                if (running) {
                                        XBell(dpy, 100);
@@ -222,7 +226,6 @@ static Lock *
 lockscreen(Display *dpy, int screen)
 {
        char curs[] = {0, 0, 0, 0, 0, 0, 0, 0};
-       unsigned int len;
        int i;
        Lock *lock;
        XColor color, dummy;
@@ -249,34 +252,31 @@ lockscreen(Display *dpy, int screen)
        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);
-       }
-       if (!len) {
+       if (XGrabPointer(dpy, lock->root, False, ButtonPressMask |
+           ButtonReleaseMask | PointerMotionMask, GrabModeAsync, GrabModeAsync,
+           None, invisible, CurrentTime) != GrabSuccess) {
                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);
-               }
+               running = 0;
+               unlockscreen(dpy, lock);
+               return NULL;
+       }
+
+       if (XGrabKeyboard(dpy, lock->root, True, GrabModeAsync, GrabModeAsync,
+           CurrentTime) != GrabSuccess) {
                fprintf(stderr, "slock: unable to grab keyboard for screen %d\n", screen);
+               running = 0;
+               unlockscreen(dpy, lock);
+               return NULL;
        }
-       /* grabbing one of the inputs failed */
-       running = 0;
-       unlockscreen(dpy, lock);
-       return NULL;
+
+       XMapRaised(dpy, lock->win);
+       if (rr)
+               XRRSelectInput(dpy, lock->win, RRScreenChangeNotifyMask);
+
+       XSelectInput(dpy, lock->root, SubstructureNotifyMask);
+       return lock;
 }
 
 static void
@@ -316,6 +316,8 @@ main(int argc, char **argv) {
 
 #ifndef HAVE_BSD_AUTH
        pws = getpw();
+       if (strlen(pws) < 2)
+               die("slock: failed to get user password hash.\n");
 #endif
 
        if (!(dpy = XOpenDisplay(NULL)))