crypto/krb5: use kfree_sensitive() for derived key buffers

[PATCH] crypto/krb5: use kfree_sensitive() for derived key buffers

Posted by Jan Sebastian Götte 1 month, 4 weeks ago

crypto_krb5_prepare_encryption() and crypto_krb5_prepare_checksum()
free the buffer holding the freshly derived keys with plain kfree(),
leaving the key material behind in the freed slab object.

Fixes: 3936f02bf2d3 ("crypto/krb5: Implement Kerberos crypto core")
Cc: stable@vger.kernel.org
Signed-off-by: Jan Sebastian Götte <linux@jaseg.de>
---
 crypto/krb5/krb5_api.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/crypto/krb5/krb5_api.c b/crypto/krb5/krb5_api.c
index 03395b89cc61..b377f4f7558d 100644
--- a/crypto/krb5/krb5_api.c
+++ b/crypto/krb5/krb5_api.c
@@ -263,10 +263,10 @@ struct crypto_aead *crypto_krb5_prepare_encryption(const struct krb5_enctype *kr
 		goto err;
 	}
 
-	kfree(keys.data);
+	kfree_sensitive(keys.data);
 	return ci;
 err:
-	kfree(keys.data);
+	kfree_sensitive(keys.data);
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL(crypto_krb5_prepare_encryption);
@@ -333,10 +333,10 @@ struct crypto_shash *crypto_krb5_prepare_checksum(const struct krb5_enctype *krb
 		goto err;
 	}
 
-	kfree(keys.data);
+	kfree_sensitive(keys.data);
 	return ci;
 err:
-	kfree(keys.data);
+	kfree_sensitive(keys.data);
 	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL(crypto_krb5_prepare_checksum);
-- 
2.53.0

Re: [PATCH] crypto/krb5: use kfree_sensitive() for derived key buffers

Posted by Herbert Xu 1 month, 2 weeks ago

On Mon, Aug 03, 2026 at 09:26:21PM +0200, Jan Sebastian Götte wrote:
> crypto_krb5_prepare_encryption() and crypto_krb5_prepare_checksum()
> free the buffer holding the freshly derived keys with plain kfree(),
> leaving the key material behind in the freed slab object.
> 
> Fixes: 3936f02bf2d3 ("crypto/krb5: Implement Kerberos crypto core")
> Cc: stable@vger.kernel.org
> Signed-off-by: Jan Sebastian Götte <linux@jaseg.de>
> ---
>  crypto/krb5/krb5_api.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt