progs/cookie.c: Constant-time MAC tag checking.

diff --git a/progs/cookie.c b/progs/cookie.c
index 56849e5..6239eb0 100644 (file)
--- a/progs/cookie.c
+++ b/progs/cookie.c
@@ -45,6 +45,7 @@
 #include <mLib/sub.h>
 
 #include "cc.h"
+#include "ct.h"
 #include "key.h"
 #include "gmac.h"
 #include "getdate.h"
@@ -485,7 +486,7 @@ static int cmd_verify(int argc, char *argv[])
     GH_HASH(h, argv[optind + 1], strlen(argv[optind + 1]));
   t = GH_DONE(h, 0);
 
-  if (memcmp(t, d.buf + COOKIE_SZ, cbits / 8) != 0) {
+  if (!ct_memeq(t, d.buf + COOKIE_SZ, cbits / 8)) {
     if (v) printf("FAIL bad authentication token\n");
     goto fail;
   }