From patchwork Tue Sep 29 10:58:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 263317 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=-13.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, 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 B0CCBC4727C for ; Tue, 29 Sep 2020 11:30:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64C3923D57 for ; Tue, 29 Sep 2020 11:30:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601379000; bh=d8LIBh664EMJWKVMgi4PoXqUWKA6nfR5sn8VKK1DXo8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=gW+T96p+H/XwbxVnlw6rfZ1PLaErYOcKHak4YElQOdaPpb4Js0RaPoCqasegHXOMu N9hiJnUdEQXRi6RWGzLk/LbONIss01ZX3k26Nrd9DChN1PUB6mk7cger35jymwGZ71 911jSpfVCdLWkuRVU+fpzcinQI6EATPuL3FxJ3yI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728256AbgI2L34 (ORCPT ); Tue, 29 Sep 2020 07:29:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:39526 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729315AbgI2L3J (ORCPT ); Tue, 29 Sep 2020 07:29:09 -0400 Received: from localhost (83-86-74-64.cable.dynamic.v4.ziggo.nl [83.86.74.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 235F121924; Tue, 29 Sep 2020 11:23:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601378599; bh=d8LIBh664EMJWKVMgi4PoXqUWKA6nfR5sn8VKK1DXo8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2u+ZoknmW+DAuYtHDAbHxb2DyrsLbdE6eioQQ9e7v7G5DJJAxe9/j8+uewC1kaGhv W/vDrMWSywMI0/ohh3H3Epr00PRPniTCV+jhaap2PNThGqjB3POv2GS9hQAm1P2Fgt WOG2bJWp3Z57lpnVPsF1pbSbCxp9/FvrcDJ0SyLI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Joe Perches , Dan Carpenter , Julia Lawall , Thomas Gleixner , Kees Cook , Andrew Morton , Linus Torvalds , Sasha Levin Subject: [PATCH 4.19 044/245] kernel/sys.c: avoid copying possible padding bytes in copy_to_user Date: Tue, 29 Sep 2020 12:58:15 +0200 Message-Id: <20200929105949.147438401@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929105946.978650816@linuxfoundation.org> References: <20200929105946.978650816@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Joe Perches [ Upstream commit 5e1aada08cd19ea652b2d32a250501d09b02ff2e ] Initialization is not guaranteed to zero padding bytes so use an explicit memset instead to avoid leaking any kernel content in any possible padding bytes. Link: http://lkml.kernel.org/r/dfa331c00881d61c8ee51577a082d8bebd61805c.camel@perches.com Signed-off-by: Joe Perches Cc: Dan Carpenter Cc: Julia Lawall Cc: Thomas Gleixner Cc: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- kernel/sys.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/sys.c b/kernel/sys.c index 096932a450466..baf60a3aa34b7 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1275,11 +1275,13 @@ SYSCALL_DEFINE1(uname, struct old_utsname __user *, name) SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name) { - struct oldold_utsname tmp = {}; + struct oldold_utsname tmp; if (!name) return -EFAULT; + memset(&tmp, 0, sizeof(tmp)); + down_read(&uts_sem); memcpy(&tmp.sysname, &utsname()->sysname, __OLD_UTS_LEN); memcpy(&tmp.nodename, &utsname()->nodename, __OLD_UTS_LEN);