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 X-Spam-Level: X-Spam-Status: No, score=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 11B66C07E9B for ; Mon, 5 Jul 2021 05:09:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EC23D613DD for ; Mon, 5 Jul 2021 05:09:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229744AbhGEFMD (ORCPT ); Mon, 5 Jul 2021 01:12:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:44136 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229447AbhGEFMD (ORCPT ); Mon, 5 Jul 2021 01:12:03 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 789E36135C; Mon, 5 Jul 2021 05:09:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625461767; bh=pn2qvBXexeI0yzGA82WBWM4m6Tz6lzaW+hkbRfk99nI=; h=From:To:Cc:Subject:Date:From; b=r48oGfBwMgOHlRA3epCFe9xWwKhm03kkAFhotYy8soa0ZVj/GoEgD6dyDMskVEKKH gQY6pft89OGrzJ9P/Ih3koXcV/Rb8qiYoJTH9LSwj5GtnFAChAJThY18NmkTB7qQYQ 0rgDNzSr5CF8KarYSuFPY9p/4dS03sQqgOwo8YzDQ3enqCW80ACFic2Av08aO+ajOP x2kf/bjhHnhh7/ZmCjDEy6Wkv6oiy0ahJIqUOQkY3EsnwqvfdV7HGU5WtWf6E6piXd YvEhFXLTazHR7tlI62EL/cl9QpYRudxd52oBywOtJ04VJmAPBuYBTYGmOIQEdGtTPt YXixRBfb2YU7A== From: Jarkko Sakkinen To: Shuah Khan Cc: linux-kselftest@vger.kernel.org, linux-sgx@vger.kernel.org, Reinette Chatre , Borislav Petkov , Tianjia Zhang , Jarkko Sakkinen , Dave Hansen , linux-kernel@vger.kernel.org Subject: [PATCH v2] selftests/sgx: Fix Q1 and Q2 calculation in sigstruct.c Date: Mon, 5 Jul 2021 08:09:21 +0300 Message-Id: <20210705050922.63710-1-jarkko@kernel.org> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Tianjia Zhang Q1 and Q2 are numbers with *maximum* length of 384 bytes. If the calculated length of Q1 and Q2 is less than 384 bytes, things will go wrong. E.g. if Q2 is 383 bytes, then 1. The bytes of q2 are copied to sigstruct->q2 in calc_q1q2(). 2. The entire sigstruct->q2 is reversed, which results it being 256 * Q2, given that the last byte of sigstruct->q2 is added to before the bytes given by calc_q1q2(). Either change in key or measurement can trigger the bug. E.g. an unmeasured heap could cause a devastating change in Q1 or Q2. Reverse exactly the bytes of Q1 and Q2 in calc_q1q2() before returning to the caller. Fixes: dedde2634570 ("selftests/sgx: Trigger the reclaimer in the selftests") Link: https://lore.kernel.org/linux-sgx/20210301051836.30738-1-tianjia.zhang@linux.alibaba.com/ Signed-off-by: Tianjia Zhang Signed-off-by: Jarkko Sakkinen --- The original patch did a bad job explaining the code change but it turned out making sense. I wrote a new description. v2: - Added a fixes tag. tools/testing/selftests/sgx/sigstruct.c | 41 +++++++++++++------------ 1 file changed, 21 insertions(+), 20 deletions(-) diff --git a/tools/testing/selftests/sgx/sigstruct.c b/tools/testing/selftests/sgx/sigstruct.c index dee7a3d6c5a5..92bbc5a15c39 100644 --- a/tools/testing/selftests/sgx/sigstruct.c +++ b/tools/testing/selftests/sgx/sigstruct.c @@ -55,10 +55,27 @@ static bool alloc_q1q2_ctx(const uint8_t *s, const uint8_t *m, return true; } +static void reverse_bytes(void *data, int length) +{ + int i = 0; + int j = length - 1; + uint8_t temp; + uint8_t *ptr = data; + + while (i < j) { + temp = ptr[i]; + ptr[i] = ptr[j]; + ptr[j] = temp; + i++; + j--; + } +} + static bool calc_q1q2(const uint8_t *s, const uint8_t *m, uint8_t *q1, uint8_t *q2) { struct q1q2_ctx ctx; + int len; if (!alloc_q1q2_ctx(s, m, &ctx)) { fprintf(stderr, "Not enough memory for Q1Q2 calculation\n"); @@ -89,8 +106,10 @@ static bool calc_q1q2(const uint8_t *s, const uint8_t *m, uint8_t *q1, goto out; } - BN_bn2bin(ctx.q1, q1); - BN_bn2bin(ctx.q2, q2); + len = BN_bn2bin(ctx.q1, q1); + reverse_bytes(q1, len); + len = BN_bn2bin(ctx.q2, q2); + reverse_bytes(q2, len); free_q1q2_ctx(&ctx); return true; @@ -152,22 +171,6 @@ static RSA *gen_sign_key(void) return key; } -static void reverse_bytes(void *data, int length) -{ - int i = 0; - int j = length - 1; - uint8_t temp; - uint8_t *ptr = data; - - while (i < j) { - temp = ptr[i]; - ptr[i] = ptr[j]; - ptr[j] = temp; - i++; - j--; - } -} - enum mrtags { MRECREATE = 0x0045544145524345, MREADD = 0x0000000044444145, @@ -367,8 +370,6 @@ bool encl_measure(struct encl *encl) /* BE -> LE */ reverse_bytes(sigstruct->signature, SGX_MODULUS_SIZE); reverse_bytes(sigstruct->modulus, SGX_MODULUS_SIZE); - reverse_bytes(sigstruct->q1, SGX_MODULUS_SIZE); - reverse_bytes(sigstruct->q2, SGX_MODULUS_SIZE); EVP_MD_CTX_destroy(ctx); RSA_free(key); -- 2.32.0