File 0003-cryptodisk-wipe-out-the-cached-keys-from-p... of Package grub2

Overview Repositories Revisions Requests Users Attributes Meta

File 0003-cryptodisk-wipe-out-the-cached-keys-from-protectors.patch of Package grub2 (Revision df352a0829b66c7e2161e27c03912ec0)

Currently displaying revision df352a0829b66c7e2161e27c03912ec0 , Show latest

From 64494ffc442a5de05b237ad48d27c70d22849a44 Mon Sep 17 00:00:00 2001
From: Gary Lin <glin@suse.com>
Date: Thu, 3 Aug 2023 15:52:52 +0800
Subject: [PATCH 3/4] cryptodisk: wipe out the cached keys from protectors

An attacker may insert a malicious disk with the same crypto UUID and
trick grub2 to mount the fake root. Even though the key from the key
protector fails to unlock the fake root, it's not wiped out cleanly so
the attacker could dump the memory to retrieve the secret key. To defend
such attack, wipe out the cached key when we don't need it.

Signed-off-by: Gary Lin <glin@suse.com>
---
 grub-core/disk/cryptodisk.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c
index cf37a0934..f42437f4e 100644
--- a/grub-core/disk/cryptodisk.c
+++ b/grub-core/disk/cryptodisk.c
@@ -1348,7 +1348,11 @@ grub_cryptodisk_clear_key_cache (struct grub_cryptomount_args *cargs)
     return;
 
   for (i = 0; cargs->protectors[i]; i++)
-    grub_free (cargs->key_cache[i].key);
+    {
+      if (cargs->key_cache[i].key)
+	grub_memset (cargs->key_cache[i].key, 0, cargs->key_cache[i].key_len);
+      grub_free (cargs->key_cache[i].key);
+    }
 
   grub_free (cargs->key_cache);
 }
-- 
2.35.3

Places

File 0003-cryptodisk-wipe-out-the-cached-keys-from-protectors.patch of Package grub2 (Revision df352a0829b66c7e2161e27c03912ec0)

Places