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

[shenyang (M)]

On 2020/9/4 15:40, Herbert Xu wrote:
> 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,

Here 'HZIP_BUF_SIZE' is 22, so the buf is enough for the string.

The check for the return is really unnecessary, I will remove it in the
next version.

Thanks,
Yang