From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2C6B8C433EF for ; Tue, 28 Jun 2022 03:16:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230095AbiF1DQF (ORCPT ); Mon, 27 Jun 2022 23:16:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38196 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229872AbiF1DQC (ORCPT ); Mon, 27 Jun 2022 23:16:02 -0400 Received: from out30-45.freemail.mail.aliyun.com (out30-45.freemail.mail.aliyun.com [115.124.30.45]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E73661706F; Mon, 27 Jun 2022 20:15:58 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R181e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045168;MF=tianjia.zhang@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0VHfHwgb_1656386154; Received: from 30.240.101.24(mailfrom:tianjia.zhang@linux.alibaba.com fp:SMTPD_---0VHfHwgb_1656386154) by smtp.aliyun-inc.com; Tue, 28 Jun 2022 11:15:55 +0800 Message-ID: Date: Tue, 28 Jun 2022 11:15:53 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH v2 RESEND] KEYS: asymmetric: enforce SM2 signature use pkey algo Content-Language: en-US To: Jarkko Sakkinen Cc: David Howells , Herbert Xu , "David S. Miller" , Gilad Ben-Yossef , Eric Biggers , keyrings@vger.kernel.org, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org References: <20220627092027.20858-1-tianjia.zhang@linux.alibaba.com> From: Tianjia Zhang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jarkko, On 6/28/22 7:14 AM, Jarkko Sakkinen wrote: > On Mon, Jun 27, 2022 at 05:20:27PM +0800, Tianjia Zhang wrote: >> The signature verification of SM2 needs to add the Za value and >> recalculate sig->digest, which requires the detection of the pkey_algo >> in public_key_verify_signature(). As Eric Biggers said, the pkey_algo >> field in sig is attacker-controlled and should be use pkey->pkey_algo >> instead of sig->pkey_algo, and secondly, if sig->pkey_algo is NULL, it >> will also cause signature verification failure. >> >> The software_key_determine_akcipher() already forces the algorithms >> are matched, so the SM3 algorithm is enforced in the SM2 signature, >> although this has been checked, we still avoid using any algorithm >> information in the signature as input. >> >> Fixes: 215525639631 ("X.509: support OSCCA SM2-with-SM3 certificate verification") >> Reported-by: Eric Biggers >> Cc: stable@vger.kernel.org # v5.10+ >> Signed-off-by: Tianjia Zhang >> --- >> crypto/asymmetric_keys/public_key.c | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/crypto/asymmetric_keys/public_key.c b/crypto/asymmetric_keys/public_key.c >> index 7c9e6be35c30..3f17ee860f89 100644 >> --- a/crypto/asymmetric_keys/public_key.c >> +++ b/crypto/asymmetric_keys/public_key.c >> @@ -309,7 +309,8 @@ static int cert_sig_digest_update(const struct public_key_signature *sig, >> if (ret) >> return ret; >> >> - tfm = crypto_alloc_shash(sig->hash_algo, 0, 0); >> + /* SM2 signatures always use the SM3 hash algorithm */ >> + tfm = crypto_alloc_shash("sm3", 0, 0); > > So, why this should not validate sig->hash_alog *to be* "sm3"? > > I.e. add instead guard before crypto_alloc_hash: > > if (strncmp(sig->hash_algo, "sm3") != 0) { > /* error */ > } > /* continue */ > Thanks, it's reasonable and I'll take your advice. Best regards, Tianjia