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Date:   Fri, 24 Mar 2023 17:48:45 +0800
From:   Herbert Xu <herbert@gondor.apana.org.au>
To:     Jia Jie Ho <jiajie.ho@starfivetech.com>
Cc:     "David S . Miller" <davem@davemloft.net>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Emil Renner Berthing <kernel@esmil.dk>,
        Conor Dooley <conor.dooley@microchip.com>,
        linux-crypto@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org
Subject: Re: [PATCH v3 4/4] crypto: starfive - Add hash and HMAC support
Message-ID: <ZB1x/bUdOSWzim+8@gondor.apana.org.au>
References: <20230313135646.2077707-1-jiajie.ho@starfivetech.com>
 <20230313135646.2077707-5-jiajie.ho@starfivetech.com>
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On Mon, Mar 13, 2023 at 09:56:46PM +0800, Jia Jie Ho wrote:
>
> +static int starfive_hash_copy_sgs(struct starfive_cryp_request_ctx *rctx)
> +{
> +	void *buf_in;
> +	int pages, total_in;
> +
> +	if (!starfive_hash_check_io_aligned(rctx)) {
> +		rctx->sgs_copied = 0;
> +		return 0;
> +	}
> +
> +	total_in = ALIGN(rctx->total, rctx->blksize);
> +	pages = total_in ? get_order(total_in) : 1;
> +	buf_in = (void *)__get_free_pages(GFP_ATOMIC, pages);

Please don't allocate the whole thing because it could be unlimited
in size (and triggered from user-space by untrusted users too).

If you have to copy, then just allocate a single page and copy
that, hash, and then repeat until it's all done.

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