37 lines
1.2 KiB
Diff
37 lines
1.2 KiB
Diff
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From 64494ffc442a5de05b237ad48d27c70d22849a44 Mon Sep 17 00:00:00 2001
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From: Gary Lin <glin@suse.com>
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Date: Thu, 3 Aug 2023 15:52:52 +0800
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Subject: [PATCH 3/4] cryptodisk: wipe out the cached keys from protectors
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An attacker may insert a malicious disk with the same crypto UUID and
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trick grub2 to mount the fake root. Even though the key from the key
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protector fails to unlock the fake root, it's not wiped out cleanly so
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the attacker could dump the memory to retrieve the secret key. To defend
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such attack, wipe out the cached key when we don't need it.
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Signed-off-by: Gary Lin <glin@suse.com>
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---
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grub-core/disk/cryptodisk.c | 6 +++++-
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1 file changed, 5 insertions(+), 1 deletion(-)
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diff --git a/grub-core/disk/cryptodisk.c b/grub-core/disk/cryptodisk.c
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index cf37a0934..f42437f4e 100644
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--- a/grub-core/disk/cryptodisk.c
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+++ b/grub-core/disk/cryptodisk.c
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@@ -1348,7 +1348,11 @@ grub_cryptodisk_clear_key_cache (struct grub_cryptomount_args *cargs)
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return;
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for (i = 0; cargs->protectors[i]; i++)
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- grub_free (cargs->key_cache[i].key);
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+ {
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+ if (cargs->key_cache[i].key)
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+ grub_memset (cargs->key_cache[i].key, 0, cargs->key_cache[i].key_len);
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+ grub_free (cargs->key_cache[i].key);
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+ }
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grub_free (cargs->key_cache);
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}
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--
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2.35.3
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