From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E2D3E15EB6 for ; Mon, 2 Oct 2023 16:44:59 +0000 (UTC) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4RzmyS5506z6K6gc; Tue, 3 Oct 2023 00:44:48 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Mon, 2 Oct 2023 17:44:55 +0100 Date: Mon, 2 Oct 2023 17:44:54 +0100 From: Jonathan Cameron To: Lukas Wunner CC: Bjorn Helgaas , David Howells , David Woodhouse , Herbert Xu , "David S. Miller" , Alex Williamson , , , , , , , , David Box , Dan Williams , Dave Jiang , "Li, Ming" , Zhi Wang , Alistair Francis , Wilfred Mallawa , Alexey Kardashevskiy , Tom Lendacky , Sean Christopherson , Alexander Graf Subject: Re: [PATCH 03/12] X.509: Move certificate length retrieval into new helper Message-ID: <20231002174454.000025c5@Huawei.com> In-Reply-To: <16c06528d13b2c0081229a45cacd4b1b9cdff738.1695921657.git.lukas@wunner.de> References: <16c06528d13b2c0081229a45cacd4b1b9cdff738.1695921657.git.lukas@wunner.de> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-coco@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml100005.china.huawei.com (7.191.160.25) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected On Thu, 28 Sep 2023 19:32:32 +0200 Lukas Wunner wrote: > The upcoming in-kernel SPDM library (Security Protocol and Data Model, > https://www.dmtf.org/dsp/DSP0274) needs to retrieve the length from > ASN.1 DER-encoded X.509 certificates. > > Such code already exists in x509_load_certificate_list(), so move it > into a new helper for reuse by SPDM. > > No functional change intended. > > Signed-off-by: Lukas Wunner Good find :) I vaguely remember carrying a hack for this so good to do something more general + save on the duplication. Reviewed-by: Jonathan Cameron > --- > crypto/asymmetric_keys/x509_loader.c | 38 +++++++++++++++++++--------- > include/keys/asymmetric-type.h | 2 ++ > 2 files changed, 28 insertions(+), 12 deletions(-) > > diff --git a/crypto/asymmetric_keys/x509_loader.c b/crypto/asymmetric_keys/x509_loader.c > index a41741326998..121460a0de46 100644 > --- a/crypto/asymmetric_keys/x509_loader.c > +++ b/crypto/asymmetric_keys/x509_loader.c > @@ -4,28 +4,42 @@ > #include > #include > > +int x509_get_certificate_length(const u8 *p, unsigned long buflen) > +{ > + int plen; > + > + /* Each cert begins with an ASN.1 SEQUENCE tag and must be more > + * than 256 bytes in size. > + */ > + if (buflen < 4) > + return -EINVAL; > + > + if (p[0] != 0x30 && > + p[1] != 0x82) > + return -EINVAL; > + > + plen = (p[2] << 8) | p[3]; > + plen += 4; > + if (plen > buflen) > + return -EINVAL; > + > + return plen; > +} > +EXPORT_SYMBOL_GPL(x509_get_certificate_length); > + > int x509_load_certificate_list(const u8 cert_list[], > const unsigned long list_size, > const struct key *keyring) > { > key_ref_t key; > const u8 *p, *end; > - size_t plen; > + int plen; > > p = cert_list; > end = p + list_size; > while (p < end) { > - /* Each cert begins with an ASN.1 SEQUENCE tag and must be more > - * than 256 bytes in size. > - */ > - if (end - p < 4) > - goto dodgy_cert; > - if (p[0] != 0x30 && > - p[1] != 0x82) > - goto dodgy_cert; > - plen = (p[2] << 8) | p[3]; > - plen += 4; > - if (plen > end - p) > + plen = x509_get_certificate_length(p, end - p); > + if (plen < 0) > goto dodgy_cert; > > key = key_create_or_update(make_key_ref(keyring, 1), > diff --git a/include/keys/asymmetric-type.h b/include/keys/asymmetric-type.h > index 69a13e1e5b2e..6705cfde25b9 100644 > --- a/include/keys/asymmetric-type.h > +++ b/include/keys/asymmetric-type.h > @@ -84,6 +84,8 @@ extern struct key *find_asymmetric_key(struct key *keyring, > const struct asymmetric_key_id *id_2, > bool partial); > > +int x509_get_certificate_length(const u8 *p, unsigned long buflen); > + > int x509_load_certificate_list(const u8 cert_list[], const unsigned long list_size, > const struct key *keyring); >