[dm-devel] [PATCH v2 11/11] crypto: skcipher: Remove VLA usage for SKCIPHER_REQUEST_ON_STACK

[Herbert Xu]

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 at gondor.apana.org.au>
> Cc: "David S. Miller" <davem at davemloft.net>
> Cc: linux-crypto at vger.kernel.org
> Signed-off-by: Kees Cook <keescook at chromium.org>

This has the same issue as the ahash reqsize patch.

Cheers,
-- 
Email: Herbert Xu <herbert at gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt