Re: [PATCH 2/2] crypto: chcr - Fix error checking

[Christophe JAILLET]

Le 13/04/2017 à 18:13, Dan Carpenter a écrit :
> 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@xxxxxxxxxx> 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@xxxxxxxxxx>
> > > > > ---
> > > > > 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
Agreed.

Having direct return after some other gotos statement puzzles my 
coccinelle scripts and are spurious (at least IMHO).

best regards,
CJ