error out early on crypt() fail

[slock.git] / slock.c

diff --git a/slock.c b/slock.c
index df5c3fe..2d57e81 100644 (file)
--- a/slock.c
+++ b/slock.c
@@ -6,6 +6,7 @@
 
 #include <ctype.h>
 #include <errno.h>
 
 #include <ctype.h>
 #include <errno.h>

+#include <grp.h>

 #include <pwd.h>
 #include <stdarg.h>
 #include <stdlib.h>
 #include <pwd.h>
 #include <stdarg.h>
 #include <stdlib.h>


@@ -13,34 +14,37 @@
 #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>
 

-#if HAVE_BSD_AUTH
-#include <login_cap.h>
-#include <bsd_auth.h>
-#endif
+#include "arg.h"
+#include "util.h"
+
+char *argv0;

 
 enum {
        INIT,
        INPUT,
 
 enum {
        INIT,
        INPUT,

-       EMPTY,
+       FAILED,

        NUMCOLS
 };
 
 #include "config.h"
 
        NUMCOLS
 };
 
 #include "config.h"
 

-typedef struct {
+struct lock {

        int screen;
        Window root, win;
        Pixmap pmap;
        unsigned long colors[NUMCOLS];
        int screen;
        Window root, win;
        Pixmap pmap;
        unsigned long colors[NUMCOLS];

-} Lock;
+};

 
 

-static Lock **locks;
-static int nscreens;
-static Bool running = True;
+struct xrandr {
+       int active;
+       int evbase;
+       int errbase;
+};

 
 static void
 die(const char *errstr, ...)
 
 static void
 die(const char *errstr, ...)


@@ -55,71 +59,83 @@ die(const char *errstr, ...)
 
 #ifdef __linux__
 #include <fcntl.h>
 
 #ifdef __linux__
 #include <fcntl.h>

+#include <linux/oom.h>

 
 static void
 dontkillme(void)
 {
 
 static void
 dontkillme(void)
 {

-       int fd;
+       FILE *f;
+       const char oomfile[] = "/proc/self/oom_score_adj";

 
 

-       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)
-               die("cannot disable the out-of-memory killer for this process\n");
+       if (!(f = fopen(oomfile, "w"))) {
+               if (errno == ENOENT)
+                       return;
+               die("slock: fopen %s: %s\n", oomfile, strerror(errno));
+       }
+       fprintf(f, "%d", OOM_SCORE_ADJ_MIN);
+       if (fclose(f)) {
+               if (errno == EACCES)
+                       die("slock: unable to disable OOM killer. "
+                           "suid or sgid set?\n");
+               else
+                       die("slock: fclose %s: %s\n", oomfile,
+                           strerror(errno));
+       }

 }
 #endif
 
 }
 #endif
 

-#ifndef HAVE_BSD_AUTH
-/* only run as root */

 static const char *
 static const char *

-getpw(void)
+gethash(void)

 {
 {

-       const char *rval;
+       const char *hash;

        struct passwd *pw;
 
        struct passwd *pw;
 

+       /* Check if the current user has a password entry */

        errno = 0;
        errno = 0;

-       pw = getpwuid(getuid());
-       if (!pw) {
+       if (!(pw = getpwuid(getuid()))) {

                if (errno)
                        die("slock: getpwuid: %s\n", strerror(errno));
                else
                        die("slock: cannot retrieve password entry\n");
        }
                if (errno)
                        die("slock: getpwuid: %s\n", strerror(errno));
                else
                        die("slock: cannot retrieve password entry\n");
        }

-       rval =  pw->pw_passwd;
+       hash = pw->pw_passwd;

 
 #if HAVE_SHADOW_H
 
 #if HAVE_SHADOW_H

-       if (rval[0] == 'x' && rval[1] == '\0') {
+       if (hash[0] == 'x' && hash[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");
-               rval = sp->sp_pwdp;
+               if (!(sp = getspnam(pw->pw_name)))
+                       die("slock: getspnam: cannot retrieve shadow entry (make sure to suid or sgid slock)\n");
+               hash = sp->sp_pwdp;

        }
        }

-#endif
+#else
+       if (hash[0] == '*' && hash[1] == '\0') {
+#ifdef __OpenBSD__
+               if (!(pw = getpwuid_shadow(getuid())))
+                       die("slock: getpwnam_shadow: cannot retrieve shadow entry (make sure to suid or sgid slock)\n");
+               hash = pw->pw_passwd;
+#else
+               die("slock: getpwuid: cannot retrieve shadow entry (make sure to suid or sgid slock)\n");
+#endif /* __OpenBSD__ */
+       }
+#endif /* HAVE_SHADOW_H */

 
 

-       /* 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;
+       return hash;

 }
 }

-#endif

 
 static void
 
 static void

-#ifdef HAVE_BSD_AUTH
-readpw(Display *dpy)
-#else
-readpw(Display *dpy, const char *pws)
-#endif
+readpw(Display *dpy, struct xrandr *rr, struct lock **locks, int nscreens,
+       const char *hash)

 {
 {

-       char buf[32], passwd[256];
-       int num, screen;
-       unsigned int len, llen;
+       char buf[32], passwd[256], *inputhash;
+       int num, screen, running, failure;
+       unsigned int len, color;

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

+       static int oldc = INIT;

 
 

-       len = llen = 0;
-       running = True;
+       len = 0;
+       running = 1;
+       failure = 0;

 
        /* As "slock" stands for "Simple X display locker", the DPMS settings
         * had been removed and you can set it with "xset" or some other
 
        /* As "slock" stands for "Simple X display locker", the DPMS settings
         * had been removed and you can set it with "xset" or some other


@@ -127,8 +143,8 @@ readpw(Display *dpy, const char *pws)
         * timeout. */
        while (running && !XNextEvent(dpy, &ev)) {
                if (ev.type == KeyPress) {
         * timeout. */
        while (running && !XNextEvent(dpy, &ev)) {
                if (ev.type == KeyPress) {

-                       buf[0] = 0;
-                       num = XLookupString(&ev.xkey, buf, sizeof buf, &ksym, 0);
+                       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;
                        if (IsKeypadKey(ksym)) {
                                if (ksym == XK_KP_Enter)
                                        ksym = XK_Return;


@@ -144,81 +160,68 @@ readpw(Display *dpy, const char *pws)
                        switch (ksym) {
                        case XK_Return:
                                passwd[len] = 0;
                        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)
+                               errno = 0;
+                               if (!(inputhash = crypt(passwd, hash)))
+                                       fprintf(stderr, "slock: crypt: %s\n", strerror(errno));
+                               else
+                                       running = !!strcmp(inputhash, hash);
+                               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:
                                if (len)
                                len = 0;
                                break;
                        case XK_BackSpace:
                                if (len)

-                                       --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;
                        }

-                       if (llen == 0 && len != 0) {
+                       color = len ? INPUT : (failure || failonclear ? FAILED : INIT);
+                       if (running && oldc != color) {

                                for (screen = 0; screen < nscreens; screen++) {
                                for (screen = 0; screen < nscreens; screen++) {

-                                       XSetWindowBackground(dpy, locks[screen]->win, locks[screen]->colors[INPUT]);
+                                       XSetWindowBackground(dpy, locks[screen]->win, locks[screen]->colors[color]);

                                        XClearWindow(dpy, locks[screen]->win);
                                }
                                        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[EMPTY]);
+                               oldc = color;
+                       }
+               } else if (rr->active && ev.type == rr->evbase + 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);
                                }
                        }
                                        XClearWindow(dpy, locks[screen]->win);
                                }
                        }

-                       llen = len;
-               }
-               else for (screen = 0; screen < nscreens; screen++)
+               } else for (screen = 0; screen < nscreens; screen++)

                        XRaiseWindow(dpy, locks[screen]->win);
        }
 }
 
                        XRaiseWindow(dpy, locks[screen]->win);
        }
 }
 

-static void
-unlockscreen(Display *dpy, Lock *lock)
-{
-       if(dpy == NULL || lock == NULL)
-               return;
-
-       XUngrabPointer(dpy, CurrentTime);
-       XFreeColors(dpy, DefaultColormap(dpy, lock->screen), lock->colors, NUMCOLS, 0);
-       XFreePixmap(dpy, lock->pmap);
-       XDestroyWindow(dpy, lock->win);
-
-       free(lock);
-}
-
-static Lock *
-lockscreen(Display *dpy, int screen)
+static struct lock *
+lockscreen(Display *dpy, struct xrandr *rr, int screen)

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

-       unsigned int len;
-       int i;
-       Lock *lock;
+       int i, ptgrab, kbgrab;
+       struct lock *lock;

        XColor color, dummy;
        XSetWindowAttributes wa;
        Cursor invisible;
 
        XColor color, dummy;
        XSetWindowAttributes wa;
        Cursor invisible;
 

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

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

-

        lock->root = RootWindow(dpy, lock->screen);
 
        for (i = 0; i < NUMCOLS; i++) {
        lock->root = RootWindow(dpy, lock->screen);
 
        for (i = 0; i < NUMCOLS; i++) {


@@ -235,98 +238,140 @@ 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);
        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);
-       for (len = 1000; len; len--) {
-               if (XGrabPointer(dpy, lock->root, False, ButtonPressMask | ButtonReleaseMask | PointerMotionMask,
-                   GrabModeAsync, GrabModeAsync, None, invisible, CurrentTime) == GrabSuccess)
-                       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);
+
+       /* Try to grab mouse pointer *and* keyboard for 600ms, else fail the lock */
+       for (i = 0, ptgrab = kbgrab = -1; i < 6; i++) {
+               if (ptgrab != GrabSuccess) {
+                       ptgrab = XGrabPointer(dpy, lock->root, False,
+                                ButtonPressMask | ButtonReleaseMask |
+                                PointerMotionMask, GrabModeAsync,
+                                GrabModeAsync, None, invisible, CurrentTime);
+               }
+               if (kbgrab != GrabSuccess) {
+                       kbgrab = XGrabKeyboard(dpy, lock->root, True,
+                                GrabModeAsync, GrabModeAsync, CurrentTime);

                }
                }

-       }

 
 

-       running &= (len > 0);
-       if (!running) {
-               unlockscreen(dpy, lock);
-               lock = NULL;
-       }
-       else {
-               XSelectInput(dpy, lock->root, SubstructureNotifyMask);
+               /* input is grabbed: we can lock the screen */
+               if (ptgrab == GrabSuccess && kbgrab == GrabSuccess) {
+                       XMapRaised(dpy, lock->win);
+                       if (rr->active)
+                               XRRSelectInput(dpy, lock->win, RRScreenChangeNotifyMask);
+
+                       XSelectInput(dpy, lock->root, SubstructureNotifyMask);
+                       return lock;
+               }
+
+               /* retry on AlreadyGrabbed but fail on other errors */
+               if ((ptgrab != AlreadyGrabbed && ptgrab != GrabSuccess) ||
+                   (kbgrab != AlreadyGrabbed && kbgrab != GrabSuccess))
+                       break;
+
+               usleep(100000);

        }
 
        }
 

-       return lock;
+       /* we couldn't grab all input: fail out */
+       if (ptgrab != GrabSuccess)
+               fprintf(stderr, "slock: unable to grab mouse pointer for screen %d\n", screen);
+       if (kbgrab != GrabSuccess)
+               fprintf(stderr, "slock: unable to grab keyboard for screen %d\n", screen);
+       return NULL;

 }
 
 static void
 usage(void)
 {
 }
 
 static void
 usage(void)
 {

-       fprintf(stderr, "usage: slock [-v]\n");
-       exit(1);
+       die("usage: slock [-v] [cmd [arg ...]]\n");

 }
 
 int
 main(int argc, char **argv) {
 }
 
 int
 main(int argc, char **argv) {

-#ifndef HAVE_BSD_AUTH
-       const char *pws;
-#endif
+       struct xrandr rr;
+       struct lock **locks;
+       struct passwd *pwd;
+       struct group *grp;
+       uid_t duid;
+       gid_t dgid;
+       const char *hash;

        Display *dpy;
        Display *dpy;

-       int screen;
+       int s, nlocks, nscreens;

 
 

-       if ((argc == 2) && !strcmp("-v", argv[1]))
-               die("slock-%s, © 2006-2015 slock engineers\n", VERSION);
-       else if (argc != 1)
+       ARGBEGIN {
+       case 'v':
+               fprintf(stderr, "slock-"VERSION"\n");
+               return 0;
+       default:

                usage();
                usage();

+       } ARGEND
+
+       /* validate drop-user and -group */
+       errno = 0;
+       if (!(pwd = getpwnam(user)))
+               die("slock: getpwnam %s: %s\n", user, errno ?
+                   strerror(errno) : "user entry not found");
+       duid = pwd->pw_uid;
+       errno = 0;
+       if (!(grp = getgrnam(group)))
+               die("slock: getgrnam %s: %s\n", group, errno ?
+                   strerror(errno) : "group entry not found");
+       dgid = grp->gr_gid;

 
 #ifdef __linux__
        dontkillme();
 #endif
 
 
 #ifdef __linux__
        dontkillme();
 #endif
 

-       if (!getpwuid(getuid()))
-               die("slock: no passwd entry for you\n");
-
-#ifndef HAVE_BSD_AUTH
-       pws = getpw();
-#endif
+       hash = gethash();
+       errno = 0;
+       if (!crypt("", hash))
+               die("slock: crypt: %s\n", strerror(errno));

 
 

-       if (!(dpy = XOpenDisplay(0)))
+       if (!(dpy = XOpenDisplay(NULL)))

                die("slock: cannot open display\n");
                die("slock: cannot open display\n");

-       /* Get the number of screens in display "dpy" and blank them all. */
+
+       /* drop privileges */
+       if (setgroups(0, NULL) < 0)
+               die("slock: setgroups: %s\n", strerror(errno));
+       if (setgid(dgid) < 0)
+               die("slock: setgid: %s\n", strerror(errno));
+       if (setuid(duid) < 0)
+               die("slock: setuid: %s\n", strerror(errno));
+
+       /* check for Xrandr support */
+       rr.active = XRRQueryExtension(dpy, &rr.evbase, &rr.errbase);
+
+       /* get number of screens in display "dpy" and blank them */

        nscreens = ScreenCount(dpy);
        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)
+       if (!(locks = calloc(nscreens, sizeof(struct lock *))))
+               die("slock: out of memory\n");
+       for (nlocks = 0, s = 0; s < nscreens; s++) {
+               if ((locks[s] = lockscreen(dpy, &rr, s)) != NULL)

                        nlocks++;
                        nlocks++;

+               else
+                       break;

        }
        }

-       XSync(dpy, False);
+       XSync(dpy, 0);

 
 

-       /* Did we actually manage to lock something? */
-       if (nlocks == 0) { /* nothing to protect */
-               free(locks);
-               XCloseDisplay(dpy);
+       /* did we manage to lock everything? */
+       if (nlocks != nscreens)

                return 1;
                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]);
+       /* run post-lock command */
+       if (argc > 0) {
+               switch (fork()) {
+               case -1:
+                       die("slock: fork failed: %s\n", strerror(errno));
+               case 0:
+                       if (close(ConnectionNumber(dpy)) < 0)
+                               die("slock: close: %s\n", strerror(errno));
+                       execvp(argv[0], argv);
+                       fprintf(stderr, "slock: execvp %s: %s\n", argv[0],
+                               strerror(errno));
+                       _exit(1);
+               }
+       }

 
 

-       free(locks);
-       XCloseDisplay(dpy);
+       /* everything is now blank. Wait for the correct password */
+       readpw(dpy, &rr, locks, nscreens, hash);

 
        return 0;
 }
 
        return 0;
 }