[PATCH v2 3/6] net/tcp-ao: clear the aes_cmac_key when done

[PATCH v2 3/6] net/tcp-ao: clear the aes_cmac_key when done

[Thomas Huth]

From: Thomas Huth <thuth@redhat.com>

Clear the local aes_cmac_key structure via __cleanup() function
when we're done with it to avoid that sensitive data could leak on
the stack.

Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 net/ipv4/tcp_ao.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/tcp_ao.c b/net/ipv4/tcp_ao.c
index e4ec60a334963..0626cbf60620c 100644
--- a/net/ipv4/tcp_ao.c
+++ b/net/ipv4/tcp_ao.c
@@ -141,7 +141,7 @@ void tcp_ao_calc_traffic_key(const struct tcp_ao_key *mkt, u8 *traffic_key,
 					traffic_key);
 		return;
 	case TCP_AO_ALGO_AES_128_CMAC: {
-		struct aes_cmac_key k;
+		struct aes_cmac_key k __cleanup(aes_cmac_zeroize_key);
 
 		aes_cmac_preparekey(&k, mkt->key, AES_KEYSIZE_128);
 		aes_cmac(&k, input, input_len, traffic_key);
-- 
2.55.0

Re: [PATCH v2 3/6] net/tcp-ao: clear the aes_cmac_key when done

[Jakub Kicinski]

On Fri,  7 Aug 2026 14:58:40 +0200 Thomas Huth wrote:
> -		struct aes_cmac_key k;
> +		struct aes_cmac_key k __cleanup(aes_cmac_zeroize_key);

Nak, we don't like the auto-cleanup stuff in networking.
If y'all need a garbage collector there're jobs programming in Java.

Re: [PATCH v2 3/6] net/tcp-ao: clear the aes_cmac_key when done

[Thomas Huth]

On 08/08/2026 00.22, Jakub Kicinski wrote:
> On Fri,  7 Aug 2026 14:58:40 +0200 Thomas Huth wrote:
>> -		struct aes_cmac_key k;
>> +		struct aes_cmac_key k __cleanup(aes_cmac_zeroize_key);
> 
> Nak, we don't like the auto-cleanup stuff in networking.

Ok, if you don't like it, then let's drop this patch.

> If y'all need a garbage collector there're jobs programming in Java.
No need for derogatory statements, Jakub. That's really inappropriate.

  Thomas