From 8b1b47efd667ea3450681fa0c674045980e25360 Mon Sep 17 00:00:00 2001
From: Jonathan Bar Or <jonathanbaror@gmail.com>
Date: Mon, 7 Apr 2025 09:36:34 +0000
Subject: [PATCH] fix CVE-2024-56738

Reference:https://savannah.gnu.org/bugs/?66603
Conflict:NA

---
 grub-core/lib/crypto.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/grub-core/lib/crypto.c b/grub-core/lib/crypto.c
index d53ddbe..653aab7 100644
--- a/grub-core/lib/crypto.c
+++ b/grub-core/lib/crypto.c
@@ -440,16 +440,16 @@ grub_crypto_gcry_error (gcry_err_code_t in)
 int
 grub_crypto_memcmp (const void *a, const void *b, grub_size_t n)
 {
-  register grub_size_t counter = 0;
-  const grub_uint8_t *pa, *pb;
+  register grub_uint8_t indicator = 0;
+  const grub_uint8_t *pa = a, *pb = b;
+  grub_size_t i;
 
-  for (pa = a, pb = b; n; pa++, pb++, n--)
+  for (i = 0; i < n; i++)
     {
-      if (*pa != *pb)
-	counter++;
+	indicator |= (pa[i] ^ pb[i]);
     }
 
-  return !!counter;
+  return !!indicator;
 }
 
 #ifndef GRUB_UTIL
-- 
2.33.0

