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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 996F7C43616 for ; Mon, 10 May 2021 11:20:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7605961041 for ; Mon, 10 May 2021 11:20:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234452AbhEJLM5 (ORCPT ); Mon, 10 May 2021 07:12:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:41768 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233528AbhEJKuM (ORCPT ); Mon, 10 May 2021 06:50:12 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7A00F61A0F; Mon, 10 May 2021 10:39:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620643168; bh=zdyythD21HvJgoFCj/9ADYkiuDf0zulSgc++zqebsM8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=q+ALVM29J+YGmloPRGI1UJvhZtcVfzkXNy9XKlD/ZL+UGqPWOCBYWZC6L9J3YxTat tPZT3HeS+ehVcrwT/YTzSsBnZfXhlt5crtSgYXlZsw9hpy59Y8kpmJprOVsR7+Z1ZK Y5x4Erz8b2WdVaOesOP4bx6fcaPFNQEdwtm0myOU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sven Schnelle , Harald Freudenberger , Heiko Carstens , Sasha Levin Subject: [PATCH 5.10 206/299] s390/archrandom: add parameter check for s390_arch_random_generate Date: Mon, 10 May 2021 12:20:03 +0200 Message-Id: <20210510102011.748799311@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210510102004.821838356@linuxfoundation.org> References: <20210510102004.821838356@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: Harald Freudenberger [ Upstream commit 28096067686c5a5cbd4c35b079749bd805df5010 ] A review of the code showed, that this function which is exposed within the whole kernel should do a parameter check for the amount of bytes requested. If this requested bytes is too high an unsigned int overflow could happen causing this function to try to memcpy a really big memory chunk. This is not a security issue as there are only two invocations of this function from arch/s390/include/asm/archrandom.h and both are not exposed to userland. Reported-by: Sven Schnelle Signed-off-by: Harald Freudenberger Signed-off-by: Heiko Carstens Signed-off-by: Sasha Levin --- arch/s390/crypto/arch_random.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/s390/crypto/arch_random.c b/arch/s390/crypto/arch_random.c index dd95cdbd22ce..4cbb4b6d85a8 100644 --- a/arch/s390/crypto/arch_random.c +++ b/arch/s390/crypto/arch_random.c @@ -53,6 +53,10 @@ static DECLARE_DELAYED_WORK(arch_rng_work, arch_rng_refill_buffer); bool s390_arch_random_generate(u8 *buf, unsigned int nbytes) { + /* max hunk is ARCH_RNG_BUF_SIZE */ + if (nbytes > ARCH_RNG_BUF_SIZE) + return false; + /* lock rng buffer */ if (!spin_trylock(&arch_rng_lock)) return false; -- 2.30.2