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=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, 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 11C19C43381 for ; Mon, 11 Jan 2021 13:53:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CE28C22287 for ; Mon, 11 Jan 2021 13:53:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387940AbhAKNxA (ORCPT ); Mon, 11 Jan 2021 08:53:00 -0500 Received: from mail.kernel.org ([198.145.29.99]:56080 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730593AbhAKNIl (ORCPT ); Mon, 11 Jan 2021 08:08:41 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id F38E82253A; Mon, 11 Jan 2021 13:07:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1610370480; bh=qUziF+x+vkE7l0Qc0ydsWSwZ/md35vyMtcMMyR3TadA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GWvq5gxpartWd8v0X87xQT9Os6Wp4MqGtaKdcnW9b5J61K0xGi4wT7k+Ye0ZOZNPy URTfsyUCxKaMZWpDBBRBlraiOoeSVpbNG2rli/ilSNHycmavW6RSJ7ro/OSsvS0wPK UjPEZrjdtTlu2rm7SsQhKqcfJsKftt/yInUPJnh0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Pavel Machek , Ard Biesheuvel , Herbert Xu Subject: [PATCH 4.19 41/77] crypto: ecdh - avoid buffer overflow in ecdh_set_secret() Date: Mon, 11 Jan 2021 14:01:50 +0100 Message-Id: <20210111130038.382400278@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210111130036.414620026@linuxfoundation.org> References: <20210111130036.414620026@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ard Biesheuvel commit 0aa171e9b267ce7c52d3a3df7bc9c1fc0203dec5 upstream. Pavel reports that commit 17858b140bf4 ("crypto: ecdh - avoid unaligned accesses in ecdh_set_secret()") fixes one problem but introduces another: the unconditional memcpy() introduced by that commit may overflow the target buffer if the source data is invalid, which could be the result of intentional tampering. So check params.key_size explicitly against the size of the target buffer before validating the key further. Fixes: 17858b140bf4 ("crypto: ecdh - avoid unaligned accesses in ecdh_set_secret()") Reported-by: Pavel Machek Cc: Signed-off-by: Ard Biesheuvel Signed-off-by: Herbert Xu Signed-off-by: Greg Kroah-Hartman --- crypto/ecdh.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/crypto/ecdh.c +++ b/crypto/ecdh.c @@ -43,7 +43,8 @@ static int ecdh_set_secret(struct crypto struct ecdh params; unsigned int ndigits; - if (crypto_ecdh_decode_key(buf, len, ¶ms) < 0) + if (crypto_ecdh_decode_key(buf, len, ¶ms) < 0 || + params.key_size > sizeof(ctx->private_key)) return -EINVAL; ndigits = ecdh_supported_curve(params.curve_id);