crypto: improve robustness of LUKS metadata validation

[PATCH 04/11] crypto: validate that LUKS payload doesn't overlap with header

Posted by Daniel P. Berrangé 3 years, 5 months ago

We already validate that LUKS keyslots don't overlap with the
header, or with each other. This closes the remain hole in
validation of LUKS file regions.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 crypto/block-luks.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/crypto/block-luks.c b/crypto/block-luks.c
index 6ef9a89ffa..f22bc63e54 100644
--- a/crypto/block-luks.c
+++ b/crypto/block-luks.c
@@ -572,6 +572,13 @@ qcrypto_block_luks_check_header(const QCryptoBlockLUKS *luks, Error **errp)
         return -1;
     }
 
+    if (luks->header.payload_offset_sector <
+        DIV_ROUND_UP(QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET,
+                     QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) {
+        error_setg(errp, "LUKS payload is overlapping with the header");
+        return -1;
+    }
+
     /* Check all keyslots for corruption  */
     for (i = 0 ; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS ; i++) {
 
-- 
2.37.2

Re: [PATCH 04/11] crypto: validate that LUKS payload doesn't overlap with header

Posted by Richard W.M. Jones 3 years, 5 months ago

On Tue, Sep 06, 2022 at 09:41:40AM +0100, Daniel P. Berrangé wrote:
> We already validate that LUKS keyslots don't overlap with the
> header, or with each other. This closes the remain hole in

remain -> remaining

> validation of LUKS file regions.
> 
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
>  crypto/block-luks.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/crypto/block-luks.c b/crypto/block-luks.c
> index 6ef9a89ffa..f22bc63e54 100644
> --- a/crypto/block-luks.c
> +++ b/crypto/block-luks.c
> @@ -572,6 +572,13 @@ qcrypto_block_luks_check_header(const QCryptoBlockLUKS *luks, Error **errp)
>          return -1;
>      }
>  
> +    if (luks->header.payload_offset_sector <
> +        DIV_ROUND_UP(QCRYPTO_BLOCK_LUKS_KEY_SLOT_OFFSET,
> +                     QCRYPTO_BLOCK_LUKS_SECTOR_SIZE)) {
> +        error_setg(errp, "LUKS payload is overlapping with the header");
> +        return -1;
> +    }
> +
>      /* Check all keyslots for corruption  */
>      for (i = 0 ; i < QCRYPTO_BLOCK_LUKS_NUM_KEY_SLOTS ; i++) {
>  
> -- 
> 2.37.2

-- 
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