swaylock: don't memset memory that has been freed

swaylock is randomly crashing because we write to password that has already been
freed in pam_authenticate().

1 files changed, 4 insertions, 5 deletions

diff --git a/swaylock/main.c b/swaylock/main.c
index e6095d35..9530b6dc 100644
--- a/swaylock/main.c
+++ b/swaylock/main.c
@@ -75,7 +75,7 @@ int function_conversation(int num_msg, const struct pam_message **msg,
 /**
  * password will be zeroed out.
  */
-bool verify_password(char *password) {
+bool verify_password() {
         struct passwd *passwd = getpwuid(getuid());
         char *username = passwd->pw_name;
 
@@ -86,14 +86,11 @@ bool verify_password(char *password) {
                 sway_abort("PAM returned %d\n", pam_err);
         }
         if ((pam_err = pam_authenticate(local_auth_handle, 0)) != PAM_SUCCESS) {
-                memset(password, 0, strlen(password));
                 return false;
         }
         if ((pam_err = pam_end(local_auth_handle, pam_err)) != PAM_SUCCESS) {
-                memset(password, 0, strlen(password));
                 return false;
         }
-        memset(password, 0, strlen(password));
         return true;
 }
 
@@ -101,9 +98,11 @@ void notify_key(enum wl_keyboard_key_state state, xkb_keysym_t sym, uint32_t cod
         if (state == WL_KEYBOARD_KEY_STATE_PRESSED) {
                 switch (sym) {
                 case XKB_KEY_Return:
-                        if (verify_password(password)) {
+                        if (verify_password()) {
                                 exit(0);
                         }
+                        password = malloc(1024); // TODO: Let this grow
+                        password[0] = '\0';
                         break;
                 default:
                         {