Re: [PATCH v2 11/11] crypto: skcipher: Remove VLA usage for SKCIPHER_REQUEST_ON_STACK

Herbert Xu
2018-06-26T09:21:07Z

On Mon, Jun 25, 2018 at 02:10:26PM -0700, Kees Cook wrote:
> In the quest to remove all stack VLA usage from the kernel[1], this
> caps the skcipher request size similar to other limits and adds a
> sanity check at registration. In a manual review of the callers of
> crypto_skcipher_set_reqsize(), the largest was 384:
>
> 4 sun4i_cipher_req_ctx
> 6 safexcel_cipher_req
> 8 cryptd_skcipher_request_ctx
> 80 cipher_req_ctx
> 80 skcipher_request
> 96 crypto_rfc3686_req_ctx
> 104 nitrox_kcrypt_request
> 144 mv_cesa_skcipher_std_req
> 384 rctx
>
> [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
>
> Cc: Herbert Xu <herbert@gondor.apana.org.au>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: linux-crypto@vger.kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>

This has the same issue as the ahash reqsize patch.

Cheers,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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