linux-kernel - Re: [PATCH] crypto: hisilicon: Wipe entire pool on error

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Message-ID: <7c9e9870-2456-01af-177f-1af62a0055e3@huawei.com>
Date:   Sat, 7 Jan 2023 09:55:04 +0800
From:   Weili Qian <qianweili@...wei.com>
To:     Kees Cook <keescook@...omium.org>
CC:     Nathan Chancellor <nathan@...nel.org>,
        Zhou Wang <wangzhou1@...ilicon.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        <linux-crypto@...r.kernel.org>,
        Nick Desaulniers <ndesaulniers@...gle.com>,
        Tom Rix <trix@...hat.com>, <linux-kernel@...r.kernel.org>,
        <llvm@...ts.linux.dev>, <linux-hardening@...r.kernel.org>
Subject: Re: [PATCH] crypto: hisilicon: Wipe entire pool on error


On 2023/1/6 12:19, Kees Cook wrote:
> To work around a Clang __builtin_object_size bug that shows up under
> CONFIG_FORTIFY_SOURCE and UBSAN_BOUNDS, move the per-loop-iteration
> mem_block wipe into a single wipe of the entire pool structure after
> the loop.
> 
> Reported-by: Nathan Chancellor <nathan@...nel.org>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1780
> Cc: Weili Qian <qianweili@...wei.com>
> Cc: Zhou Wang <wangzhou1@...ilicon.com>
> Cc: Herbert Xu <herbert@...dor.apana.org.au>
> Cc: "David S. Miller" <davem@...emloft.net>
> Cc: linux-crypto@...r.kernel.org
> Signed-off-by: Kees Cook <keescook@...omium.org>
> ---
>  drivers/crypto/hisilicon/sgl.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/crypto/hisilicon/sgl.c b/drivers/crypto/hisilicon/sgl.c
> index 2b6f2281cfd6..0974b0041405 100644
> --- a/drivers/crypto/hisilicon/sgl.c
> +++ b/drivers/crypto/hisilicon/sgl.c
> @@ -124,9 +124,8 @@ struct hisi_acc_sgl_pool *hisi_acc_create_sgl_pool(struct device *dev,
>  	for (j = 0; j < i; j++) {
>  		dma_free_coherent(dev, block_size, block[j].sgl,
>  				  block[j].sgl_dma);
> -		memset(block + j, 0, sizeof(*block));
>  	}
> -	kfree(pool);
> +	kfree_sensitive(pool);
>  	return ERR_PTR(-ENOMEM);
>  }
>  EXPORT_SYMBOL_GPL(hisi_acc_create_sgl_pool);
> 
Thanks for your patch.

There is no sensitive data in the pool, so memset zero can be deleted directly.

Thanks,
Weili