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From:   David Laight <David.Laight@ACULAB.COM>
To:     'Yang Shen' <shenyang39@huawei.com>,
        "herbert@gondor.apana.org.au" <herbert@gondor.apana.org.au>,
        "davem@davemloft.net" <davem@davemloft.net>
CC:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
        "xuzaibo@huawei.com" <xuzaibo@huawei.com>,
        "wangzhou1@hisilicon.com" <wangzhou1@hisilicon.com>
Subject: RE: [PATCH RESEND 04/10] crypto: hisilicon/zip - replace 'sprintf'
 with 'scnprintf'
Thread-Topic: [PATCH RESEND 04/10] crypto: hisilicon/zip - replace 'sprintf'
 with 'scnprintf'
Thread-Index: AQHWecS3Jx83/+rMLUuKUpSHllsCl6lG7Xzg
Date:   Mon, 24 Aug 2020 08:29:36 +0000
Message-ID: <d1102aca2bdc4df4acc31d8b082cacce@AcuMS.aculab.com>
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 <1598238709-58699-5-git-send-email-shenyang39@huawei.com>
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From: Yang Shen
> Sent: 24 August 2020 04:12
> 
> Replace 'sprintf' with 'scnprintf' to avoid overrun.
> 
> Signed-off-by: Yang Shen <shenyang39@huawei.com>
> Reviewed-by: Zhou Wang <wangzhou1@hisilicon.com>
> ---
>  drivers/crypto/hisilicon/zip/zip_main.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/crypto/hisilicon/zip/zip_main.c b/drivers/crypto/hisilicon/zip/zip_main.c
> index df1a16f..1883d1b 100644
> --- a/drivers/crypto/hisilicon/zip/zip_main.c
> +++ b/drivers/crypto/hisilicon/zip/zip_main.c
> @@ -428,7 +428,7 @@ static ssize_t hisi_zip_ctrl_debug_read(struct file *filp, char __user *buf,
>  		return -EINVAL;
>  	}
>  	spin_unlock_irq(&file->lock);
> -	ret = sprintf(tbuf, "%u\n", val);
> +	ret = scnprintf(tbuf, HZIP_BUF_SIZE, "%u\n", val);

Should that be sizeof (tbuf).

>  	return simple_read_from_buffer(buf, count, pos, tbuf, ret);
>  }
> 
> @@ -514,13 +514,16 @@ static int hisi_zip_core_debug_init(struct hisi_qm *qm)
>  	struct debugfs_regset32 *regset;
>  	struct dentry *tmp_d;
>  	char buf[HZIP_BUF_SIZE];
> -	int i;
> +	int i, ret;
> 
>  	for (i = 0; i < HZIP_CORE_NUM; i++) {
>  		if (i < HZIP_COMP_CORE_NUM)
> -			sprintf(buf, "comp_core%d", i);
> +			ret = scnprintf(buf, HZIP_BUF_SIZE, "comp_core%d", i);
>  		else
> -			sprintf(buf, "decomp_core%d", i - HZIP_COMP_CORE_NUM);
> +			ret = scnprintf(buf, HZIP_BUF_SIZE, "decomp_core%d",
> +					i - HZIP_COMP_CORE_NUM);
> +		if (!ret)
> +			return -ENOMEM;

and that is just so wrong - did you even try to test
the 'buffer too small' code path?

	David

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