X-Git-Url: https://git.xinqibao.xyz/slock.git/blobdiff_plain/a6dc051e3744ce5b14c54d2d246d3e8258207e76..2d85c5baed4c4b4ecc19f7934fac1fc6a5b5c410:/slock.c

diff --git a/slock.c b/slock.c
index 4531f95..c81f5dd 100644
--- a/slock.c
+++ b/slock.c
@@ -6,6 +6,7 @@
 
 #include <ctype.h>
 #include <errno.h>
+#include <grp.h>
 #include <pwd.h>
 #include <stdarg.h>
 #include <stdlib.h>
@@ -18,10 +19,10 @@
 #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,
@@ -32,20 +33,18 @@ enum {
 
 #include "config.h"
 
-typedef struct {
+struct lock {
 	int screen;
 	Window root, win;
 	Pixmap pmap;
 	unsigned long colors[NUMCOLS];
-} Lock;
+};
 
-static Lock **locks;
-static int nscreens;
-static Bool running = True;
-static Bool failure = False;
-static Bool rr;
-static int rrevbase;
-static int rrerrbase;
+struct xrandr {
+	int active;
+	int evbase;
+	int errbase;
+};
 
 static void
 die(const char *errstr, ...)
@@ -60,31 +59,38 @@ die(const char *errstr, ...)
 
 #ifdef __linux__
 #include <fcntl.h>
+#include <linux/oom.h>
 
 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 (!(f = fopen(oomfile, "w"))) {
+		if (errno == ENOENT)
+			return;
+		die("slock: fopen %s: %s\n", oomfile, strerror(errno));
 	}
-	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");
+	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
 
-#ifndef HAVE_BSD_AUTH
-/* only run as root */
 static const char *
-getpw(void)
+gethash(void)
 {
-	const char *rval;
+	const char *hash;
 	struct passwd *pw;
 
+	/* Check if the current user has a password entry */
 	errno = 0;
 	if (!(pw = getpwuid(getuid()))) {
 		if (errno)
@@ -92,49 +98,48 @@ getpw(void)
 		else
 			die("slock: cannot retrieve password entry\n");
 	}
-	rval = pw->pw_passwd;
+	hash = pw->pw_passwd;
 
 #if HAVE_SHADOW_H
-	if (rval[0] == 'x' && rval[1] == '\0') {
+	if (hash[0] == 'x' && hash[1] == '\0') {
 		struct spwd *sp;
-		if (!(sp = getspnam(getenv("USER"))))
-			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
-#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;
+	char buf[32], passwd[256], *inputhash;
+	int num, screen, running, failure;
 	unsigned int len, color;
 	KeySym ksym;
 	XEvent ev;
 	static int oldc = INIT;
 
 	len = 0;
-	running = True;
+	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
-	 * utility. This way the user can easily set a customized DPMS
-	 * timeout. */
 	while (running && !XNextEvent(dpy, &ev)) {
 		if (ev.type == KeyPress) {
-			buf[0] = 0;
+			explicit_bzero(&buf, sizeof(buf));
 			num = XLookupString(&ev.xkey, buf, sizeof(buf), &ksym, 0);
 			if (IsKeypadKey(ksym)) {
 				if (ksym == XK_KP_Enter)
@@ -151,23 +156,25 @@ readpw(Display *dpy, const char *pws)
 			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
+				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);
 					failure = True;
 				}
+				explicit_bzero(&passwd, sizeof(passwd));
 				len = 0;
 				break;
 			case XK_Escape:
+				explicit_bzero(&passwd, sizeof(passwd));
 				len = 0;
 				break;
 			case XK_BackSpace:
 				if (len)
-					--len;
+					passwd[len--] = 0;
 				break;
 			default:
 				if (num && !iscntrl((int)buf[0]) && (len + num < sizeof(passwd))) {
@@ -184,7 +191,7 @@ readpw(Display *dpy, const char *pws)
 				}
 				oldc = color;
 			}
-		} else if (rr && ev.type == rrevbase + RRScreenChangeNotify) {
+		} 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) {
@@ -197,32 +204,17 @@ readpw(Display *dpy, const char *pws)
 	}
 }
 
-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};
-	unsigned int len;
-	int i;
-	Lock *lock;
+	int i, ptgrab, kbgrab;
+	struct lock *lock;
 	XColor color, dummy;
 	XSetWindowAttributes wa;
 	Cursor invisible;
 
-	if (!running || dpy == NULL || screen < 0 || !(lock = malloc(sizeof(Lock))))
+	if (dpy == NULL || screen < 0 || !(lock = malloc(sizeof(struct lock))))
 		return NULL;
 
 	lock->screen = screen;
@@ -242,97 +234,140 @@ 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);
-	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)
+
+	/* 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);
+		}
+
+		/* 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(1000);
+
+		usleep(100000);
 	}
-	if (!len) {
+
+	/* we couldn't grab all input: fail out */
+	if (ptgrab != 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);
-		}
+	if (kbgrab != GrabSuccess)
 		fprintf(stderr, "slock: unable to grab keyboard for screen %d\n", screen);
-	}
-	/* grabbing one of the inputs failed */
-	running = 0;
-	unlockscreen(dpy, lock);
 	return NULL;
 }
 
-int
-main(int argc, char **argv)
+static void
+usage(void)
 {
-#ifndef HAVE_BSD_AUTH
-	const char *pws;
-#endif
+	die("usage: slock [-v] [cmd [arg ...]]\n");
+}
+
+int
+main(int argc, char **argv) {
+	struct xrandr rr;
+	struct lock **locks;
+	struct passwd *pwd;
+	struct group *grp;
+	uid_t duid;
+	gid_t dgid;
+	const char *hash;
 	Display *dpy;
-	int screen;
+	int s, nlocks, nscreens;
+
+	ARGBEGIN {
+	case 'v':
+		fprintf(stderr, "slock-"VERSION"\n");
+		return 0;
+	default:
+		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
 
-	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");
-	rr = XRRQueryExtension(dpy, &rrevbase, &rrerrbase);
-	/* 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);
-	if (!(locks = malloc(sizeof(Lock*) * nscreens)))
-		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++;
+		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;
-	}
 
-	if (argc >= 2 && fork() == 0) {
-		if (dpy)
-			close(ConnectionNumber(dpy));
-		execvp(argv[1], argv+1);
-		die("slock: execvp %s failed: %s\n", argv[1], strerror(errno));
+	/* 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);
+		}
 	}
 
-	/* 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);
+	/* everything is now blank. Wait for the correct password */
+	readpw(dpy, &rr, locks, nscreens, hash);
 
 	return 0;
 }