Re: [PATCH] crypto: hisilicon/hpre - Fix a erroneous check after snprintf()

[Marion & Christophe JAILLET]

Le 05/09/2023 à 04:27, Herbert Xu a écrit :
> On Mon, Sep 04, 2023 at 10:17:29PM +0200, Christophe JAILLET wrote:
> > This error handling looks really strange.
> > Check if the string has been truncated instead.
> >
> > Fixes: 02ab994635eb ("crypto: hisilicon - Fixed some tiny bugs of HPRE")
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > ---
> >   drivers/crypto/hisilicon/hpre/hpre_main.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/crypto/hisilicon/hpre/hpre_main.c b/drivers/crypto/hisilicon/hpre/hpre_main.c
> > index 39297ce70f44..db44d889438a 100644
> > --- a/drivers/crypto/hisilicon/hpre/hpre_main.c
> > +++ b/drivers/crypto/hisilicon/hpre/hpre_main.c
> > @@ -1033,7 +1033,7 @@ static int hpre_cluster_debugfs_init(struct hisi_qm *qm)
> >   
> >   	for (i = 0; i < clusters_num; i++) {
> >   		ret = snprintf(buf, HPRE_DBGFS_VAL_MAX_LEN, "cluster%d", i);
> > -		if (ret < 0)
> > +		if (ret >= HPRE_DBGFS_VAL_MAX_LEN)
> >   			return -EINVAL;
> >   		tmp_d = debugfs_create_dir(buf, qm->debug.debug_root);
> Who is going to free the allocated memory in case of error?

Not sure to understand.

The memory is allocated with devm_kzalloc(), so it will be freed by the 
framework.

Some debugfs dir of file way be left around. Is it what your are talking 
about?

> The other snprintf in the same file also looks suspect.

It looks correct to me.

And HPRE_DBGFS_VAL_MAX_LEN being 20, it doesn't really matter. The 
string can't be truncated with just a "%u\n".

CJ

> Thanks,