crypto: xilinx - clear AES key buffer before freeing it

[PATCH] crypto: xilinx - clear AES key buffer before freeing it

Posted by Thorsten Blum 2 weeks, 3 days ago

In xilinx_aes_aead_exit(), the AES key buffer is freed without being
cleared, which allows key material to remain in memory. Use
kfree_sensitive() to clear the buffer before freeing it.

Fixes: c315cb0005be ("crypto: xilinx - Change coherent DMA to streaming DMA API")
Cc: stable@vger.kernel.org
Signed-off-by: Thorsten Blum <blum@kernel.org>
---
 drivers/crypto/xilinx/zynqmp-aes-gcm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/crypto/xilinx/zynqmp-aes-gcm.c b/drivers/crypto/xilinx/zynqmp-aes-gcm.c
index d54c268dfe34..ebee37dddb1f 100644
--- a/drivers/crypto/xilinx/zynqmp-aes-gcm.c
+++ b/drivers/crypto/xilinx/zynqmp-aes-gcm.c
@@ -766,7 +766,7 @@ static void xilinx_aes_aead_exit(struct crypto_aead *aead)
 	struct xilinx_aead_tfm_ctx *tfm_ctx = crypto_tfm_ctx(tfm);
 
 	dma_unmap_single(tfm_ctx->dev, tfm_ctx->key_dma_addr, AES_KEYSIZE_256, DMA_TO_DEVICE);
-	kfree(tfm_ctx->key);
+	kfree_sensitive(tfm_ctx->key);
 	if (tfm_ctx->fbk_cipher) {
 		crypto_free_aead(tfm_ctx->fbk_cipher);
 		tfm_ctx->fbk_cipher = NULL;

Re: [PATCH] crypto: xilinx - clear AES key buffer before freeing it

Posted by Herbert Xu 1 week ago

On Tue, Sep 08, 2026 at 09:16:06PM +0200, Thorsten Blum wrote:
> In xilinx_aes_aead_exit(), the AES key buffer is freed without being
> cleared, which allows key material to remain in memory. Use
> kfree_sensitive() to clear the buffer before freeing it.
> 
> Fixes: c315cb0005be ("crypto: xilinx - Change coherent DMA to streaming DMA API")
> Cc: stable@vger.kernel.org
> Signed-off-by: Thorsten Blum <blum@kernel.org>
> ---
>  drivers/crypto/xilinx/zynqmp-aes-gcm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

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

Re: [PATCH] crypto: xilinx - clear AES key buffer before freeing it

Posted by Thomas Huth 2 weeks, 2 days ago

On 08/09/2026 21.16, Thorsten Blum wrote:
> In xilinx_aes_aead_exit(), the AES key buffer is freed without being
> cleared, which allows key material to remain in memory. Use
> kfree_sensitive() to clear the buffer before freeing it.
> 
> Fixes: c315cb0005be ("crypto: xilinx - Change coherent DMA to streaming DMA API")
> Cc: stable@vger.kernel.org
> Signed-off-by: Thorsten Blum <blum@kernel.org>
> ---
>   drivers/crypto/xilinx/zynqmp-aes-gcm.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/crypto/xilinx/zynqmp-aes-gcm.c b/drivers/crypto/xilinx/zynqmp-aes-gcm.c
> index d54c268dfe34..ebee37dddb1f 100644
> --- a/drivers/crypto/xilinx/zynqmp-aes-gcm.c
> +++ b/drivers/crypto/xilinx/zynqmp-aes-gcm.c
> @@ -766,7 +766,7 @@ static void xilinx_aes_aead_exit(struct crypto_aead *aead)
>   	struct xilinx_aead_tfm_ctx *tfm_ctx = crypto_tfm_ctx(tfm);
>   
>   	dma_unmap_single(tfm_ctx->dev, tfm_ctx->key_dma_addr, AES_KEYSIZE_256, DMA_TO_DEVICE);
> -	kfree(tfm_ctx->key);
> +	kfree_sensitive(tfm_ctx->key);
>   	if (tfm_ctx->fbk_cipher) {
>   		crypto_free_aead(tfm_ctx->fbk_cipher);
>   		tfm_ctx->fbk_cipher = NULL;
Reviewed-by: Thomas Huth <thuth@redhat.com>