From patchwork Thu May 20 09:17:22 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 445780 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=-19.1 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=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 703E8C433ED for ; Thu, 20 May 2021 09:44:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 508A561984 for ; Thu, 20 May 2021 09:44:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233687AbhETJqJ (ORCPT ); Thu, 20 May 2021 05:46:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:47526 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233704AbhETJoF (ORCPT ); Thu, 20 May 2021 05:44:05 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 8FC286144B; Thu, 20 May 2021 09:33:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1621503184; bh=zdyythD21HvJgoFCj/9ADYkiuDf0zulSgc++zqebsM8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=KqkhobQpQDyEtpu5kW0ER1/QoSJ+Yb+dTtI5IuHM4aVSPTV4yb3rbm08n1kgTxKVD axCSdVo0l9RTQwg4QgAjerC8lJZkIGSEYJkUWUYwm21TEsDSpnik5agj1Mt2ntx+RF ozwKJi3helgbU97E5AlwSeSJhdQihW8XrVk7lTM8= 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 4.19 073/425] s390/archrandom: add parameter check for s390_arch_random_generate Date: Thu, 20 May 2021 11:17:22 +0200 Message-Id: <20210520092133.851267903@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210520092131.308959589@linuxfoundation.org> References: <20210520092131.308959589@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@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;