From patchwork Wed Aug 4 16:18:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jonathan Cameron X-Patchwork-Id: 12419421 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0D2BC432BE for ; Wed, 4 Aug 2021 16:22:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8FE5960F94 for ; Wed, 4 Aug 2021 16:22:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234482AbhHDQWf (ORCPT ); Wed, 4 Aug 2021 12:22:35 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:3578 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236749AbhHDQWf (ORCPT ); Wed, 4 Aug 2021 12:22:35 -0400 Received: from fraeml737-chm.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4GfxpR4JZWz6F80H; Thu, 5 Aug 2021 00:22:07 +0800 (CST) Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by fraeml737-chm.china.huawei.com (10.206.15.218) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Wed, 4 Aug 2021 18:22:20 +0200 Received: from localhost.localdomain (10.123.41.22) by lhreml710-chm.china.huawei.com (10.201.108.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Wed, 4 Aug 2021 17:22:20 +0100 From: Jonathan Cameron To: , CC: , , Chris Browy , , Lorenzo Pieralisi , Bjorn Helgaas , Jeremy Kerr , Jonathan Cameron Subject: [RFC PATCH 1/4] lib/asn1_encoder: Add a function to encode many byte integer values. Date: Thu, 5 Aug 2021 00:18:36 +0800 Message-ID: <20210804161839.3492053-2-Jonathan.Cameron@huawei.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20210804161839.3492053-1-Jonathan.Cameron@huawei.com> References: <20210804161839.3492053-1-Jonathan.Cameron@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.123.41.22] X-ClientProxiedBy: lhreml754-chm.china.huawei.com (10.201.108.204) To lhreml710-chm.china.huawei.com (10.201.108.61) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org An example is the encoding of ECC signatures used by the ECDSA signature verification code. A user is the new SPDM support where raw signatures are returned by the responder. These can then be encoded so that we can pass them to signature_verify() Signed-off-by: Jonathan Cameron --- Needs considerably more testing with crafted examples to hit the corner cases. For now it's enough to show how this 'might' fit together. include/linux/asn1_encoder.h | 3 ++ lib/asn1_encoder.c | 54 ++++++++++++++++++++++++++++++++++++ 2 files changed, 57 insertions(+) diff --git a/include/linux/asn1_encoder.h b/include/linux/asn1_encoder.h index 08cd0c2ad34f..30c3ebacd46c 100644 --- a/include/linux/asn1_encoder.h +++ b/include/linux/asn1_encoder.h @@ -19,6 +19,9 @@ unsigned char * asn1_encode_tag(unsigned char *data, const unsigned char *end_data, u32 tag, const unsigned char *string, int len); unsigned char * +asn1_encode_integer_large_positive(unsigned char *data, const unsigned char *end_data, + u32 tag, const unsigned char *integer, int len); +unsigned char * asn1_encode_octet_string(unsigned char *data, const unsigned char *end_data, const unsigned char *string, u32 len); diff --git a/lib/asn1_encoder.c b/lib/asn1_encoder.c index 41e71aae3ef6..135c5cf2d77e 100644 --- a/lib/asn1_encoder.c +++ b/lib/asn1_encoder.c @@ -317,6 +317,60 @@ asn1_encode_tag(unsigned char *data, const unsigned char *end_data, } EXPORT_SYMBOL_GPL(asn1_encode_tag); +unsigned char * +asn1_encode_integer_large_positive(unsigned char *data, const unsigned char *end_data, + u32 tag, const unsigned char *integer, int len) +{ + int data_len = end_data - data; + unsigned char *d = &data[2]; + bool found = false; + int i; + + if (WARN(tag > 30, "ASN.1 tag can't be > 30")) + return ERR_PTR(-EINVAL); + + if (!integer && WARN(len > 127, + "BUG: recode tag is too big (>127)")) + return ERR_PTR(-EINVAL); + + if (IS_ERR(data)) + return data; + + if (data_len < 3) + return ERR_PTR(-EINVAL); + + + data[0] = _tagn(UNIV, PRIM, tag); + /* Leave space for length */ + data_len -= 2; + + for (i = 0; i < len; i++) { + int byte = integer[i]; + + if (!found && byte == 0) + continue; + + /* + * as per encode_integer + */ + if (!found && (byte & 0x80)) { + *d++ = 0; + data_len--; + } + found = true; + if (data_len == 0) + return ERR_PTR(-EINVAL); + + *d++ = byte; + data_len--; + } + + data[1] = d - data - 2; + + return d; +} +EXPORT_SYMBOL_GPL(asn1_encode_integer_large_positive); + /** * asn1_encode_octet_string() - encode an ASN.1 OCTET STRING * @data: pointer to encode at