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Subject: Re: [PATCH 2/6] security/keys/encrypted: Clean up
 request_trusted_key()
From:   Mimi Zohar <zohar@linux.ibm.com>
To:     Dan Williams <dan.j.williams@intel.com>
Cc:     keyrings@vger.kernel.org, James Bottomley <jejb@linux.ibm.com>,
        David Howells <dhowells@redhat.com>,
        Vishal L Verma <vishal.l.verma@intel.com>,
        linux-nvdimm <linux-nvdimm@lists.01.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Date:   Tue, 19 Mar 2019 22:35:31 -0400
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On Tue, 2019-03-19 at 17:20 -0700, Dan Williams wrote:
> On Tue, Mar 19, 2019 at 5:07 PM Mimi Zohar <zohar@linux.ibm.com> wrote:
> >
> > On Mon, 2019-03-18 at 23:06 -0700, Dan Williams wrote:
> >
> > < snip >
> >
> > > +/*
> > > + * request_trusted_key - request the trusted key
> > > + *
> > > + * Trusted keys are sealed to PCRs and other metadata. Although userspace
> > > + * manages both trusted/encrypted key-types, like the encrypted key type
> > > + * data, trusted key type data is not visible decrypted from userspace.
> > > + */
> > > +static struct key *request_trusted_key(const char *trusted_desc,
> > > +                             const u8 **master_key, size_t *master_keylen)
> > > +{
> > > +     struct trusted_key_payload *tpayload;
> > > +     struct key_type *type;
> > > +     struct key *tkey;
> > > +
> > > +     type = key_type_lookup("trusted");
> >
> > The associated key_type_put() will need to be called.
> 
> Yes.

I don't know if defining a key_type_lookup() wrapper, perhaps named
is_key_type_available(), would help.  Both key_type_lookup() and
key_type_put() would be called.  The existing code could then remain
the same.

Mimi

> 
> >
> > > +     if (IS_ERR(type)) {
> > > +             tkey = (struct key *)type;
> > > +             goto error;
> > > +     }
> > > +     tkey = request_key(type, trusted_desc, NULL);
> > > +     if (IS_ERR(tkey))
> > > +             goto error;
> > > +
> > > +     down_read(&tkey->sem);
> > > +     tpayload = tkey->payload.data[0];
> > > +     *master_key = tpayload->key;
> > > +     *master_keylen = tpayload->key_len;
> > > +error:
> > > +     return tkey;
> > > +}
> > > +
> >