Re: [PATCH RESEND 04/10] crypto: hisilicon/zip - replace 'sprintf' with 'scnprintf'

From: Herbert Xu <herbert@gondor.apana.org.au>
To: "shenyang (M)" <shenyang39@huawei.com>
Cc: David Laight <David.Laight@ACULAB.COM>,
	"davem@davemloft.net" <davem@davemloft.net>,
	"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'
Date: Fri, 4 Sep 2020 17:40:04 +1000	[thread overview]
Message-ID: <20200904074004.GA24815@gondor.apana.org.au> (raw)
In-Reply-To: <abc0c78e-3232-9081-c330-3d5b8db9e683@huawei.com>

On Wed, Aug 26, 2020 at 04:56:40PM +0800, shenyang (M) wrote:
>
> > > @@ -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?
> 
> Do you means the check is unnecessary?

No he's saying that your patch does the wrong thing when the string
is truncated.

Also ENOMEM is a strange error for that case.

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