fix CVE-2016-6866

1 files changed, 8 insertions, 2 deletions

diff --git a/slock.c b/slock.c
index 847b328..8ed59ca 100644
--- 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;
@@ -159,7 +159,11 @@ readpw(Display *dpy, const char *pws)
 #ifdef HAVE_BSD_AUTH
                                 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);
@@ -312,6 +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)))