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From: Vitaly Chikunov <vt@altlinux.org>
To: David Howells <dhowells@redhat.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
	Mimi Zohar <zohar@linux.ibm.com>,
	linux-integrity@vger.kernel.org, keyrings@vger.kernel.org,
	linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 04/10] crypto: akcipher - new verify API for public key algorithms
Date: Thu, 28 Feb 2019 21:39:23 +0300	[thread overview]
Message-ID: <20190228183923.5klzwli5zmeew54j@altlinux.org> (raw)
In-Reply-To: <14843.1551377934@warthog.procyon.org.uk>

David,

On Thu, Feb 28, 2019 at 06:18:54PM +0000, David Howells wrote:
> Vitaly Chikunov <vt@altlinux.org> wrote:
> 
> > +	digest = kmemdup(sig->digest, sig->digest_size, GFP_KERNEL);
> > +	if (!digest)
> 
> You shouldn't need to copy the digest.  It's being passed in to the crypto
> algorithm, not extracted out.

That's how Herbert suggested to do it. Quoting FYI:

| On Fri, Feb 01, 2019 at 02:26:55PM +0800, Herbert Xu wrote:
| > On Fri, Jan 25, 2019 at 09:01:16PM +0300, Vitaly Chikunov wrote:
| > >
| > > @@ -781,36 +780,17 @@ static int tpm_key_verify_signature(const struct key *key,
| > >     if (!req)
| > >             goto error_free_tfm;
| > >
| > > -   ret = -ENOMEM;
| > > -   outlen = crypto_akcipher_maxsize(tfm);
| > > -   output = kmalloc(outlen, GFP_KERNEL);
| > > -   if (!output)
| > > -           goto error_free_req;
| > > -
| > > -   sg_init_one(&sig_sg, sig->s, sig->s_size);
| > > -   sg_init_one(&digest_sg, output, outlen);
| > > -   akcipher_request_set_crypt(req, &sig_sg, &digest_sg, sig->s_size,
| > > -                              outlen);
| > > +   sg_init_table(&src_sg, 2);
| > > +   sg_set_buf(&src_sg[0], sig->s, sig->s_size);
| > > +   sg_set_buf(&src_sg[1], sig->digest, sig->digest_size);
| > > +   akcipher_request_set_crypt(req, &src_sg, NULL, sig->s_size,
| > > +                              sig->digest_size);
| >
| > It's not clear that sig->digest is guaranteed to be kmalloc memory.
| > In any case, it's best not to mix unrelated changes in a single
| > patch.  So please keep the kmalloc on output and then copy
| > sig->digest into it and put output into the SG list.


> > +		if (memcmp(c, outbuf_enc, c_size)) {
> 
> Please use == 0 and != 0 with memcmp() and strcmp().  Their return values are
> kind of inverted in sense if you treat them as boolean.

OK.

Thanks!


  reply	other threads:[~2019-02-28 18:39 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-24  6:08 [PATCH v5 00/10] crypto: add EC-RDSA (GOST 34.10) algorithm Vitaly Chikunov
2019-02-24  6:08 ` [PATCH v5 01/10] KEYS: report to keyctl only actually supported key ops Vitaly Chikunov
2019-02-24  6:08 ` [PATCH v5 02/10] crypto: akcipher - check the presence of callback before the call Vitaly Chikunov
2019-02-24  6:08 ` [PATCH v5 03/10] crypto: rsa - unimplement sign/verify for raw RSA backends Vitaly Chikunov
2019-02-24  6:08 ` [PATCH v5 04/10] crypto: akcipher - new verify API for public key algorithms Vitaly Chikunov
2019-02-27 23:28   ` Mimi Zohar
2019-02-28  5:37     ` Vitaly Chikunov
2019-02-24  6:08 ` [PATCH v5 05/10] X.509: parse public key parameters from x509 for akcipher Vitaly Chikunov
2019-02-24  6:08 ` [PATCH v5 06/10] crypto: Kconfig - create Public-key cryptography section Vitaly Chikunov
2019-02-24  6:08 ` [PATCH v5 07/10] crypto: ecc - make ecc into separate module Vitaly Chikunov
2019-02-24  6:08 ` [PATCH v5 08/10] crypto: ecrdsa - add EC-RDSA (GOST 34.10) algorithm Vitaly Chikunov
2019-02-24  6:08 ` [PATCH v5 09/10] crypto: ecrdsa - add EC-RDSA test vectors to testmgr Vitaly Chikunov
2019-02-24  6:08 ` [PATCH v5 10/10] integrity: support EC-RDSA signatures for asymmetric_verify Vitaly Chikunov
2019-02-25 21:20   ` Thiago Jung Bauermann
2019-02-26  4:25     ` Vitaly Chikunov
2019-02-26 12:07       ` Mimi Zohar
2019-02-28 18:18 ` [PATCH v5 04/10] crypto: akcipher - new verify API for public key algorithms David Howells
2019-02-28 18:39   ` Vitaly Chikunov [this message]
2019-02-28 19:02   ` David Howells
2019-02-28 19:07     ` Vitaly Chikunov
2019-03-01  2:34       ` Herbert Xu

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