linux-kernel - Re: [PATCH 2/2] crypto: chcr

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Date:   Thu, 13 Apr 2017 19:13:42 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     Harsh Jain <harshjain.prof@...il.com>
Cc:     Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Herbert Xu <herbert@...dor.apana.org.au>, davem@...emloft.net,
        harsh@...lsio.com, hariprasad@...lsio.com,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org
Subject: Re: [PATCH 2/2] crypto: chcr - Fix error checking

On Thu, Apr 13, 2017 at 08:37:50PM +0530, Harsh Jain wrote:
> On Thu, Apr 13, 2017 at 8:20 PM, Christophe JAILLET
> <christophe.jaillet@...adoo.fr> wrote:
> > Le 13/04/2017 à 16:04, Dan Carpenter a écrit :
> >>
> >> On Thu, Apr 13, 2017 at 02:14:30PM +0200, Christophe JAILLET wrote:
> >>>
> >>> If 'chcr_alloc_shash()' a few lines above fails, 'base_hash' can be an
> >>> error pointer when we 'goto out'.
> >>> So checking for NULL here is not enough because it is likely that
> >>> 'chcr_free_shash' will crash if we pass an error pointer.
> >>>
> >>> Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
> >>> ---
> >>> Another solution, amybe safer, would be to instrument 'chcr_free_shash'
> >>> or
> >>> 'crypto_free_shash' to accept an error pointer and return immediatelly in
> >>> such a case.
> >>> ---
> >>>   drivers/crypto/chelsio/chcr_algo.c | 2 +-
> >>>   1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/crypto/chelsio/chcr_algo.c
> >>> b/drivers/crypto/chelsio/chcr_algo.c
> >>> index f19590ac8775..41750b97f43c 100644
> >>> --- a/drivers/crypto/chelsio/chcr_algo.c
> >>> +++ b/drivers/crypto/chelsio/chcr_algo.c
> >>> @@ -2351,7 +2351,7 @@ static int chcr_authenc_setkey(struct crypto_aead
> >>> *authenc, const u8 *key,
> >>>         }
> >>>   out:
> >>>         aeadctx->enckey_len = 0;
> >>> -       if (base_hash)
> >>> +       if (!IS_ERR_OR_NULL(base_hash))
> >>>                 chcr_free_shash(base_hash);
> >>
> >> Ah...  Ok.  Fine, but redo the first patch anyway because it shouldn't
> >> ever be NULL.
> >>
> >> regards,
> >> dan carpenter
> >
> > Hi Dan,
> >
> > I will update the first patch as you proposed in order to:
> >    - teach 'chcr_alloc_shash' not to return NULL
> >    - initialize 'base_hash' with ERR_PTR(-EINVAL)
> >    - update the above test to !IS_ERR.
> > The 2 patches will be merged in only 1.
> >
> > Thanks for your suggestions.
> 
> Thanks for pointing the error. or You can simply return instead of
> goto. Just like that.
> 
>      1.3 @@ -2455,7 +2455,8 @@ static int chcr_authenc_setkey(struct cr
>      1.4   base_hash  = chcr_alloc_shash(max_authsize);
>      1.5   if (IS_ERR(base_hash)) {
>      1.6   pr_err("chcr : Base driver cannot be loaded\n");
>      1.7 - goto out;
>      1.8 + aeadctx->enckey_len = 0;
>      1.9 + return -EINVAL;

Don't do that.  There should be a goto.

regards,
dan carpenter