Re: [PATCH 1/2] crypto: lrw - Fix an error handling path in 'create()'

[Christophe JAILLET]

Le 09/10/2017 Ã 23:22, walter harms a ÃcritÂ:
> Am 08.10.2017 11:39, schrieb Christophe JAILLET:
> > All error handling paths 'goto err_drop_spawn' except this one.
> > In order to avoid some resources leak, we should do it as well here.
> >
> > Fixes: 700cb3f5fe75 ("crypto: lrw - Convert to skcipher")
> > Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
> > ---
> >   crypto/lrw.c | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/crypto/lrw.c b/crypto/lrw.c
> > index a8bfae4451bf..eb681e9fe574 100644
> > --- a/crypto/lrw.c
> > +++ b/crypto/lrw.c
> > @@ -610,8 +610,10 @@ static int create(struct crypto_template *tmpl, struct rtattr **tb)
> >   		ecb_name[len - 1] = 0;
> >   
> >   		if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
> > -			     "lrw(%s)", ecb_name) >= CRYPTO_MAX_ALG_NAME)
> 	this check can be done more easy,
> 	the length of ecb_name is len
> 	the length of inst->alg.base.cra_name is CRYPTO_MAX_ALG_NAME
> 	if CRYPTO_MAX_ALG_NAME-len < "lrw()" < 5
> 		no need to involve snprintf()
>
> 	just my 2 cents
> 	re,
>   		wh
It does not only check for the length, it also copies some data.
The test should be read: "If the copy succeeds (i.e if there is enough 
space for the copy to succeed)", and not "if the string is too long".
IMHO, the snprintf is just fine here.

CJ
> > -			return -ENAMETOOLONG;
> > +			     "lrw(%s)", ecb_name) >= CRYPTO_MAX_ALG_NAME) {
> > +			err = -ENAMETOOLONG;
> > +			goto err_drop_spawn;
> > +		}
> >   	}
> >   
> >   	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;