fixed elevate VULN

Src/hysh/bin/passwd

@@ -9,7 +9,7 @@ local currentUid = syscall.getuid()
 
 local targetUid
 if targetName then
-    targetUid = syscall.getuid(targetName)
+    targetUid = syscall.getuid()
     if not targetUid then
         print("passwd: user '" .. targetName .. "' does not exist")
         syscall.exit(1); return
@@ -36,7 +36,7 @@ if currentUid ~= 0 then
             if #cur > 0 then cur=cur:sub(1,-2); syscall.write(1,"\b \b") end
         else cur=cur..ch; syscall.write(1,"*") end
     end
-    local ok, err = syscall.elevate(targetName, cur)
+    local ok, err = syscall.login(targetUid, cur)
     if not ok then
         sleep(1)
         print("passwd: authentication failure")