linux-kernel - Re: [PATCH 1/3 v2] crypto: introduce the flag CRYPTO_ALG_ALLOCATES

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Date:   Sun, 28 Jun 2020 12:46:39 -0700
From:   Eric Biggers <ebiggers@...nel.org>
To:     Mikulas Patocka <mpatocka@...hat.com>
Cc:     Herbert Xu <herbert@...dor.apana.org.au>,
        Mike Snitzer <msnitzer@...hat.com>,
        linux-kernel@...r.kernel.org, dm-devel@...hat.com,
        linux-crypto@...r.kernel.org,
        "David S. Miller" <davem@...emloft.net>,
        Milan Broz <mbroz@...hat.com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        George Cherian <gcherian@...vell.com>,
        Wei Xu <xuwei5@...ilicon.com>, Zaibo Xu <xuzaibo@...wei.com>
Subject: Re: [PATCH 1/3 v2] crypto: introduce the flag
 CRYPTO_ALG_ALLOCATES_MEMORY

On Sun, Jun 28, 2020 at 03:04:22PM -0400, Mikulas Patocka wrote:
> > > Index: linux-2.6/crypto/authenc.c
> > > ===================================================================
> > > --- linux-2.6.orig/crypto/authenc.c	2020-06-26 17:24:03.566417000 +0200
> > > +++ linux-2.6/crypto/authenc.c	2020-06-26 17:24:03.566417000 +0200
> > > @@ -388,7 +388,8 @@ static int crypto_authenc_create(struct
> > >  	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
> > >  		return -EINVAL;
> > >  
> > > -	mask = crypto_requires_sync(algt->type, algt->mask);
> > > +	mask = crypto_requires_sync(algt->type, algt->mask) |
> > > +	       crypto_requires_nomem(algt->type, algt->mask);
> > 
> > As I suggested earlier, shouldn't there be a function that returns the mask for
> > all inherited flags, rather than handling each flag individually?
> 
> Yes - I've created crypto_requires_inherited for this purpose.

Since all callers pass in 'struct crypto_attr_type', a better helper might be:

static inline int crypto_algt_inherited_mask(struct crypto_attr_type *algt)
{
	return crypto_requires_off(algt->type, algt->mask,
				   CRYPTO_ALG_INHERITED_FLAGS);
}

> > > @@ -424,7 +425,7 @@ static int crypto_authenc_create(struct
> > >  		goto err_free_inst;
> > >  
> > >  	inst->alg.base.cra_flags = (auth_base->cra_flags |
> > > -				    enc->base.cra_flags) & CRYPTO_ALG_ASYNC;
> > > +			enc->base.cra_flags) & CRYPTO_ALG_INHERITED_FLAGS;
> > 
> > Strange indentation here.  Likewise in most of the other files.
> 
> I was told that the code should be 80-characters wide.

You could use:

	inst->alg.base.cra_flags =
		(auth_base->cra_flags | enc->base.cra_flags) &
		CRYPTO_ALG_INHERITED_FLAGS;

Just a suggestion, it's not a big deal...  Your indentation of the continuation
line just seems weird.

> > > --- linux-2.6.orig/crypto/xts.c	2020-06-26 17:24:03.566417000 +0200
> > > +++ linux-2.6/crypto/xts.c	2020-06-26 17:24:03.566417000 +0200
> > > @@ -415,7 +415,7 @@ static int create(struct crypto_template
> > >  	} else
> > >  		goto err_free_inst;
> > >  
> > > -	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
> > > +	inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_INHERITED_FLAGS;
> > >  	inst->alg.base.cra_priority = alg->base.cra_priority;
> > >  	inst->alg.base.cra_blocksize = XTS_BLOCK_SIZE;
> > >  	inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
> > 
> > Need to set the mask correctly in this file.
> 
> I don't know what do you mean.

I mean that the CRYPTO_ALG_ALLOCATES_MEMORY flag is not handled when the 'mask'
variable is assigned to earlier in this function.

It should use your new helper function, like all the other places in this patch.

- Eric