From patchwork Mon Feb 8 15:00:37 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 379273 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=-19.3 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, URIBL_BLOCKED, 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 11B51C433DB for ; Mon, 8 Feb 2021 15:05:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C373A64EC5 for ; Mon, 8 Feb 2021 15:05:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231137AbhBHPF2 (ORCPT ); Mon, 8 Feb 2021 10:05:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:52060 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232876AbhBHPD5 (ORCPT ); Mon, 8 Feb 2021 10:03:57 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 58E7F64EB7; Mon, 8 Feb 2021 15:03:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1612796606; bh=5n1+5pAYKydUCiYwImBD9lr7EVtVsDVK+XpcP8nmQNU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=kmvpBhnPW7osq9RSpeWmaGTnObtvBCAOAjz4Mm2tRei4w6gvevo8KXmX6EsZj75p/ ws1YATvSLdGKYEull7SYQBMRTyS8UdKgj9hvLwNb6o/FXBVVc12bVf2gZ8YeCCMdgD Da21R9Lz1uu6YO4mZIKRDzAlg632Jbcd/VLlNqZQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sasha Levin Subject: [PATCH 4.4 15/38] stable: clamp SUBLEVEL in 4.4 and 4.9 Date: Mon, 8 Feb 2021 16:00:37 +0100 Message-Id: <20210208145805.898658055@linuxfoundation.org> X-Mailer: git-send-email 2.30.0 In-Reply-To: <20210208145805.279815326@linuxfoundation.org> References: <20210208145805.279815326@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Right now SUBLEVEL is overflowing, and some userspace may start treating 4.9.256 as 4.10. While out of tree modules have different ways of extracting the version number (and we're generally ok with breaking them), we do care about breaking userspace and it would appear that this overflow might do just that. Our rules around userspace ABI in the stable kernel are pretty simple: we don't break it. Thus, while userspace may be checking major/minor, it shouldn't be doing anything with sublevel. This patch applies a big band-aid to the 4.9 and 4.4 kernels in the form of clamping their sublevel to 255. The clamp is done for the purpose of LINUX_VERSION_CODE only, and extracting the version number from the Makefile or "make kernelversion" will continue to work as intended. We might need to do it later in newer trees, but maybe we'll have a better solution by then, so I'm ignoring that problem for now. Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/Makefile +++ b/Makefile @@ -1068,7 +1068,7 @@ endef define filechk_version.h (echo \#define LINUX_VERSION_CODE $(shell \ - expr $(VERSION) \* 65536 + 0$(PATCHLEVEL) \* 256 + 0$(SUBLEVEL)); \ + expr $(VERSION) \* 65536 + 0$(PATCHLEVEL) \* 256 + 255); \ echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + (c))';) endef