Subject: Re: [PATCH] crypto: nx: fix nx_crypto_ctx_exit argument

From: Eric Biggers <[email-masked]>
Date: Fri, 22 May 2026 13:44:03 -0500

On Fri, May 22, 2026 at 07:01:42PM +0100, Sam James wrote:
> nx_crypto_ctx_shash_exit calls nx_crypto_ctx_exit with crypto_shash_ctx(...)
> but crypto_shash_ctx gives a nx_crypto_ctx *, not a crypto_tfm *.
> 
> Fix the type in nx_crypto_ctx_exit and drop the bogus crypto_tfm_ctx
> call.
> 
> This fixes the following oops:
> 
>   BUG: Unable to handle kernel data access at 0xc0403effffffffc8
>   Faulting instruction address: 0xc000000000396cb4
>   Oops: Kernel access of bad area, sig: 11 [#15]
>   Call Trace:
>    nx_crypto_ctx_shash_exit+0x24/0x60
>    crypto_shash_exit_tfm+0x28/0x40
>    crypto_destroy_tfm+0x98/0x140
>    crypto_exit_ahash_using_shash+0x20/0x40
>    crypto_destroy_tfm+0x98/0x140
>    hash_release+0x1c/0x30
>    alg_sock_destruct+0x38/0x60
>    __sk_destruct+0x48/0x2b0
>    af_alg_release+0x58/0xb0
>    __sock_release+0x68/0x150
>    sock_close+0x20/0x40
>    __fput+0x110/0x3a0
>    sys_close+0x48/0xa0
>    system_call_exception+0x140/0x2d0
>    system_call_common+0xf4/0x258
> 
> .. which came from hardlink(1) opportunistically using AF_ALG.
> 
> The same problem exists with nx_crypto_ctx_skcipher_exit getting a context
> it wasn't expecting, but apparently nobody hit that for years.
> 
> Cc: Eric Biggers <[email-masked]>
> Fixes: bfd9efddf990 ("crypto: nx - convert AES-ECB to skcipher API")
> Fixes: 9420e628e7d8 ("crypto: nx - Use API partial block handling")

Add:

    Cc: [email-masked]

> diff --git a/drivers/crypto/nx/nx.c b/drivers/crypto/nx/nx.c
> index 78135fb13f5c..101e7fc7c1af 100644
> --- a/drivers/crypto/nx/nx.c
> +++ b/drivers/crypto/nx/nx.c
> @@ -719,10 +719,8 @@ int nx_crypto_ctx_aes_xcbc_init(struct crypto_shash *tfm)
>   * @tfm: the crypto transform pointer for the context
>   *
>   * As crypto API contexts are destroyed, this exit hook is called to free the
>   * memory associated with it.
>   */
> -void nx_crypto_ctx_exit(struct crypto_tfm *tfm)
> +void nx_crypto_ctx_exit(struct nx_crypto_ctx *nx_ctx)

The part of the comment that documents @tfm needs to be updated.

Otherwise this looks good.  Really there's a good chance this driver is
no longer useful (if it ever was) and should just be deleted, but that
would be a separate effort.

Reviewed-by: Eric Biggers <[email-masked]>

- Eric