From: Herbert Xu <herbert@gondor.apana.org.au>
To: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Cc: "David S. Miller" <davem@davemloft.net>,
linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RESEND] SHASH_DESC_ON_STACK macro
Date: Tue, 27 Mar 2018 18:07:09 +0800 [thread overview]
Message-ID: <20180327100709.GA12961@gondor.apana.org.au> (raw)
In-Reply-To: <bda66faa-f52d-215d-f21b-763593b30f91@embeddedor.com>
On Fri, Mar 23, 2018 at 02:09:46PM -0500, Gustavo A. R. Silva wrote:
>
> Hi Herbert,
>
> There is an ongoing effort to remove all VLAs from the code base [1] and
> while working on that I came across the following macro at
> include/crypto/hash.h:154:
>
> #define SHASH_DESC_ON_STACK(shash, ctx) \
> char __##shash##_desc[sizeof(struct shash_desc) + \
> crypto_shash_descsize(ctx)] CRYPTO_MINALIGN_ATTR; \
> struct shash_desc *shash = (struct shash_desc *)__##shash##_desc
>
>
> Currently, this macro is being used in 46 different places.
>
> I wonder how big can tfm->descsize can get?
descsize is capped at PAGE_SIZE / 8.
Cheers,
--
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
next prev parent reply other threads:[~2018-03-27 10:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-21 15:07 [RFC] SHASH_DESC_ON_STACK macro Gustavo A. R. Silva
2018-03-23 19:09 ` [RESEND] " Gustavo A. R. Silva
2018-03-27 10:07 ` Herbert Xu [this message]
2018-04-05 8:26 ` Gustavo A. R. Silva
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