From patchwork Tue Sep 29 10:56:41 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: 290908 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 086DDC4727C for ; Tue, 29 Sep 2020 12:14:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A8EDD20759 for ; Tue, 29 Sep 2020 12:14:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601381650; bh=7OB6RWjA1q5chzgCBY94D09Hb0OdN7JRaoGvy11b7iw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=TwguQVfdOCruswj6bDBZufErZiiRh4VEyN+Cg8eYo/ithtHfuwwPDZA8HmPYopCzL FXnHNtscRmuCeRJi8KlaHfGO/MoS3tggcdPtXDexmX7zAvCHVWqPT5cYogZOlggOCx G0cOXMS/YIimOt4trN6qWPxlUHiYTs5Dr3j4jEjk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732181AbgI2MOJ (ORCPT ); Tue, 29 Sep 2020 08:14:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:54448 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730107AbgI2Lh2 (ORCPT ); Tue, 29 Sep 2020 07:37:28 -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 EFC6A23B23; Tue, 29 Sep 2020 11:33:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1601379228; bh=7OB6RWjA1q5chzgCBY94D09Hb0OdN7JRaoGvy11b7iw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IV9/MImZmtAVW74dqAikx0SgF3F8k9z3+jXSLmMDYF+0qxZDJrSsfo3+1Ypi+LKzL 2K35V2NgdVyz7GZc2DJY+u96B6mJEUsAejKowTX26ytCx1L8Nnb38N9w5dCzvruBx/ Yohh56biYRfugmv2NLVEUO4J0ej25Tu3DFYWodow= 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 5.4 070/388] kernel/sys.c: avoid copying possible padding bytes in copy_to_user Date: Tue, 29 Sep 2020 12:56:41 +0200 Message-Id: <20200929110013.885898127@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200929110010.467764689@linuxfoundation.org> References: <20200929110010.467764689@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 a611d1d58c7d0..3459a5ce0da01 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1279,11 +1279,13 @@ 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);