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.
Cc: Fabian Vogt <fv...@suse.com>
Signed-off-by: Gary Lin <g...@suse.com>
Reviewed-by: Stefan Berger <stef...@linux.ibm.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 8f00f22a8..3b19f2d2d 100644
--- a/grub-core/disk/cryptodisk.c
+++ b/grub-core/disk/cryptodisk.c
@@ -1349,7 +1349,11 @@ 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
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